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libpcap-1.10.4
gencode.c
9 993 строки
257 KB
Francois-Xavier Le Bail
Fix spaces before tabs in indentation
15 фев 2023, 22:48
15 фев 2023, 22:48
8355c90
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/* * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that: (1) source code distributions * retain the above copyright notice and this paragraph in its entirety, (2) * distributions including binary code include the above copyright notice and * this paragraph in its entirety in the documentation or other materials * provided with the distribution, and (3) all advertising materials mentioning * features or use of this software display the following acknowledgement: * ``This product includes software developed by the University of California, * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of * the University nor the names of its contributors may be used to endorse * or promote products derived from this software without specific prior * written permission. * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. */ #ifdef HAVE_CONFIG_H #include <config.h> #endif #ifdef _WIN32 #include <ws2tcpip.h> #else #include <sys/socket.h> #ifdef __NetBSD__ #include <sys/param.h> #endif #include <netinet/in.h> #include <arpa/inet.h> #endif /* _WIN32 */ #include <stdlib.h> #include <string.h> #include <memory.h> #include <setjmp.h> #include <stdarg.h> #include <stdio.h> #ifdef MSDOS #include "pcap-dos.h" #endif #include "pcap-int.h" #include "extract.h" #include "ethertype.h" #include "nlpid.h" #include "llc.h" #include "gencode.h" #include "ieee80211.h" #include "atmuni31.h" #include "sunatmpos.h" #include "pflog.h" #include "ppp.h" #include "pcap/sll.h" #include "pcap/ipnet.h" #include "arcnet.h" #include "diag-control.h" #include "scanner.h" #if defined(linux) #include <linux/types.h> #include <linux/if_packet.h> #include <linux/filter.h> #endif #ifndef offsetof #define offsetof(s, e) ((size_t)&((s *)0)->e) #endif #ifdef _WIN32 #ifdef INET6 #if defined(__MINGW32__) && defined(DEFINE_ADDITIONAL_IPV6_STUFF) /* IPv6 address */ struct in6_addr { union { uint8_t u6_addr8[16]; uint16_t u6_addr16[8]; uint32_t u6_addr32[4]; } in6_u; #define s6_addr in6_u.u6_addr8 #define s6_addr16 in6_u.u6_addr16 #define s6_addr32 in6_u.u6_addr32 #define s6_addr64 in6_u.u6_addr64 }; typedef unsigned short sa_family_t; #define __SOCKADDR_COMMON(sa_prefix) \ sa_family_t sa_prefix##family /* Ditto, for IPv6. */ struct sockaddr_in6 { __SOCKADDR_COMMON (sin6_); uint16_t sin6_port; /* Transport layer port # */ uint32_t sin6_flowinfo; /* IPv6 flow information */ struct in6_addr sin6_addr; /* IPv6 address */ }; #ifndef EAI_ADDRFAMILY struct addrinfo { int ai_flags; /* AI_PASSIVE, AI_CANONNAME */ int ai_family; /* PF_xxx */ int ai_socktype; /* SOCK_xxx */ int ai_protocol; /* 0 or IPPROTO_xxx for IPv4 and IPv6 */ size_t ai_addrlen; /* length of ai_addr */ char *ai_canonname; /* canonical name for hostname */ struct sockaddr *ai_addr; /* binary address */ struct addrinfo *ai_next; /* next structure in linked list */ }; #endif /* EAI_ADDRFAMILY */ #endif /* defined(__MINGW32__) && defined(DEFINE_ADDITIONAL_IPV6_STUFF) */ #endif /* INET6 */ #else /* _WIN32 */ #include <netdb.h> /* for "struct addrinfo" */ #endif /* _WIN32 */ #include <pcap/namedb.h> #include "nametoaddr.h" #define ETHERMTU 1500 #ifndef IPPROTO_HOPOPTS #define IPPROTO_HOPOPTS 0 #endif #ifndef IPPROTO_ROUTING #define IPPROTO_ROUTING 43 #endif #ifndef IPPROTO_FRAGMENT #define IPPROTO_FRAGMENT 44 #endif #ifndef IPPROTO_DSTOPTS #define IPPROTO_DSTOPTS 60 #endif #ifndef IPPROTO_SCTP #define IPPROTO_SCTP 132 #endif #define GENEVE_PORT 6081 #ifdef HAVE_OS_PROTO_H #include "os-proto.h" #endif #define JMP(c) ((c)|BPF_JMP|BPF_K) /* * "Push" the current value of the link-layer header type and link-layer * header offset onto a "stack", and set a new value. (It's not a * full-blown stack; we keep only the top two items.) */ #define PUSH_LINKHDR(cs, new_linktype, new_is_variable, new_constant_part, new_reg) \ { \ (cs)->prevlinktype = (cs)->linktype; \ (cs)->off_prevlinkhdr = (cs)->off_linkhdr; \ (cs)->linktype = (new_linktype); \ (cs)->off_linkhdr.is_variable = (new_is_variable); \ (cs)->off_linkhdr.constant_part = (new_constant_part); \ (cs)->off_linkhdr.reg = (new_reg); \ (cs)->is_geneve = 0; \ } /* * Offset "not set" value. */ #define OFFSET_NOT_SET 0xffffffffU /* * Absolute offsets, which are offsets from the beginning of the raw * packet data, are, in the general case, the sum of a variable value * and a constant value; the variable value may be absent, in which * case the offset is only the constant value, and the constant value * may be zero, in which case the offset is only the variable value. * * bpf_abs_offset is a structure containing all that information: * * is_variable is 1 if there's a variable part. * * constant_part is the constant part of the value, possibly zero; * * if is_variable is 1, reg is the register number for a register * containing the variable value if the register has been assigned, * and -1 otherwise. */ typedef struct { int is_variable; u_int constant_part; int reg; } bpf_abs_offset; /* * Value passed to gen_load_a() to indicate what the offset argument * is relative to the beginning of. */ enum e_offrel { OR_PACKET, /* full packet data */ OR_LINKHDR, /* link-layer header */ OR_PREVLINKHDR, /* previous link-layer header */ OR_LLC, /* 802.2 LLC header */ OR_PREVMPLSHDR, /* previous MPLS header */ OR_LINKTYPE, /* link-layer type */ OR_LINKPL, /* link-layer payload */ OR_LINKPL_NOSNAP, /* link-layer payload, with no SNAP header at the link layer */ OR_TRAN_IPV4, /* transport-layer header, with IPv4 network layer */ OR_TRAN_IPV6 /* transport-layer header, with IPv6 network layer */ }; /* * We divy out chunks of memory rather than call malloc each time so * we don't have to worry about leaking memory. It's probably * not a big deal if all this memory was wasted but if this ever * goes into a library that would probably not be a good idea. * * XXX - this *is* in a library.... */ #define NCHUNKS 16 #define CHUNK0SIZE 1024 struct chunk { size_t n_left; void *m; }; /* Code generator state */ struct _compiler_state { jmp_buf top_ctx; pcap_t *bpf_pcap; int error_set; struct icode ic; int snaplen; int linktype; int prevlinktype; int outermostlinktype; bpf_u_int32 netmask; int no_optimize; /* Hack for handling VLAN and MPLS stacks. */ u_int label_stack_depth; u_int vlan_stack_depth; /* XXX */ u_int pcap_fddipad; /* * As errors are handled by a longjmp, anything allocated must * be freed in the longjmp handler, so it must be reachable * from that handler. * * One thing that's allocated is the result of pcap_nametoaddrinfo(); * it must be freed with freeaddrinfo(). This variable points to * any addrinfo structure that would need to be freed. */ struct addrinfo *ai; /* * Another thing that's allocated is the result of pcap_ether_aton(); * it must be freed with free(). This variable points to any * address that would need to be freed. */ u_char *e; /* * Various code constructs need to know the layout of the packet. * These values give the necessary offsets from the beginning * of the packet data. */ /* * Absolute offset of the beginning of the link-layer header. */ bpf_abs_offset off_linkhdr; /* * If we're checking a link-layer header for a packet encapsulated * in another protocol layer, this is the equivalent information * for the previous layers' link-layer header from the beginning * of the raw packet data. */ bpf_abs_offset off_prevlinkhdr; /* * This is the equivalent information for the outermost layers' * link-layer header. */ bpf_abs_offset off_outermostlinkhdr; /* * Absolute offset of the beginning of the link-layer payload. */ bpf_abs_offset off_linkpl; /* * "off_linktype" is the offset to information in the link-layer * header giving the packet type. This is an absolute offset * from the beginning of the packet. * * For Ethernet, it's the offset of the Ethernet type field; this * means that it must have a value that skips VLAN tags. * * For link-layer types that always use 802.2 headers, it's the * offset of the LLC header; this means that it must have a value * that skips VLAN tags. * * For PPP, it's the offset of the PPP type field. * * For Cisco HDLC, it's the offset of the CHDLC type field. * * For BSD loopback, it's the offset of the AF_ value. * * For Linux cooked sockets, it's the offset of the type field. * * off_linktype.constant_part is set to OFFSET_NOT_SET for no * encapsulation, in which case, IP is assumed. */ bpf_abs_offset off_linktype; /* * TRUE if the link layer includes an ATM pseudo-header. */ int is_atm; /* * TRUE if "geneve" appeared in the filter; it causes us to * generate code that checks for a Geneve header and assume * that later filters apply to the encapsulated payload. */ int is_geneve; /* * TRUE if we need variable length part of VLAN offset */ int is_vlan_vloffset; /* * These are offsets for the ATM pseudo-header. */ u_int off_vpi; u_int off_vci; u_int off_proto; /* * These are offsets for the MTP2 fields. */ u_int off_li; u_int off_li_hsl; /* * These are offsets for the MTP3 fields. */ u_int off_sio; u_int off_opc; u_int off_dpc; u_int off_sls; /* * This is the offset of the first byte after the ATM pseudo_header, * or -1 if there is no ATM pseudo-header. */ u_int off_payload; /* * These are offsets to the beginning of the network-layer header. * They are relative to the beginning of the link-layer payload * (i.e., they don't include off_linkhdr.constant_part or * off_linkpl.constant_part). * * If the link layer never uses 802.2 LLC: * * "off_nl" and "off_nl_nosnap" are the same. * * If the link layer always uses 802.2 LLC: * * "off_nl" is the offset if there's a SNAP header following * the 802.2 header; * * "off_nl_nosnap" is the offset if there's no SNAP header. * * If the link layer is Ethernet: * * "off_nl" is the offset if the packet is an Ethernet II packet * (we assume no 802.3+802.2+SNAP); * * "off_nl_nosnap" is the offset if the packet is an 802.3 packet * with an 802.2 header following it. */ u_int off_nl; u_int off_nl_nosnap; /* * Here we handle simple allocation of the scratch registers. * If too many registers are alloc'd, the allocator punts. */ int regused[BPF_MEMWORDS]; int curreg; /* * Memory chunks. */ struct chunk chunks[NCHUNKS]; int cur_chunk; }; /* * For use by routines outside this file. */ /* VARARGS */ void bpf_set_error(compiler_state_t *cstate, const char *fmt, ...) { va_list ap; /* * If we've already set an error, don't override it. * The lexical analyzer reports some errors by setting * the error and then returning a LEX_ERROR token, which * is not recognized by any grammar rule, and thus forces * the parse to stop. We don't want the error reported * by the lexical analyzer to be overwritten by the syntax * error. */ if (!cstate->error_set) { va_start(ap, fmt); (void)vsnprintf(cstate->bpf_pcap->errbuf, PCAP_ERRBUF_SIZE, fmt, ap); va_end(ap); cstate->error_set = 1; } } /* * For use *ONLY* in routines in this file. */ static void PCAP_NORETURN bpf_error(compiler_state_t *, const char *, ...) PCAP_PRINTFLIKE(2, 3); /* VARARGS */ static void PCAP_NORETURN bpf_error(compiler_state_t *cstate, const char *fmt, ...) { va_list ap; va_start(ap, fmt); (void)vsnprintf(cstate->bpf_pcap->errbuf, PCAP_ERRBUF_SIZE, fmt, ap); va_end(ap); longjmp(cstate->top_ctx, 1); /*NOTREACHED*/ #ifdef _AIX PCAP_UNREACHABLE #endif /* _AIX */ } static int init_linktype(compiler_state_t *, pcap_t *); static void init_regs(compiler_state_t *); static int alloc_reg(compiler_state_t *); static void free_reg(compiler_state_t *, int); static void initchunks(compiler_state_t *cstate); static void *newchunk_nolongjmp(compiler_state_t *cstate, size_t); static void *newchunk(compiler_state_t *cstate, size_t); static void freechunks(compiler_state_t *cstate); static inline struct block *new_block(compiler_state_t *cstate, int); static inline struct slist *new_stmt(compiler_state_t *cstate, int); static struct block *gen_retblk(compiler_state_t *cstate, int); static inline void syntax(compiler_state_t *cstate); static void backpatch(struct block *, struct block *); static void merge(struct block *, struct block *); static struct block *gen_cmp(compiler_state_t *, enum e_offrel, u_int, u_int, bpf_u_int32); static struct block *gen_cmp_gt(compiler_state_t *, enum e_offrel, u_int, u_int, bpf_u_int32); static struct block *gen_cmp_ge(compiler_state_t *, enum e_offrel, u_int, u_int, bpf_u_int32); static struct block *gen_cmp_lt(compiler_state_t *, enum e_offrel, u_int, u_int, bpf_u_int32); static struct block *gen_cmp_le(compiler_state_t *, enum e_offrel, u_int, u_int, bpf_u_int32); static struct block *gen_mcmp(compiler_state_t *, enum e_offrel, u_int, u_int, bpf_u_int32, bpf_u_int32); static struct block *gen_bcmp(compiler_state_t *, enum e_offrel, u_int, u_int, const u_char *); static struct block *gen_ncmp(compiler_state_t *, enum e_offrel, u_int, u_int, bpf_u_int32, int, int, bpf_u_int32); static struct slist *gen_load_absoffsetrel(compiler_state_t *, bpf_abs_offset *, u_int, u_int); static struct slist *gen_load_a(compiler_state_t *, enum e_offrel, u_int, u_int); static struct slist *gen_loadx_iphdrlen(compiler_state_t *); static struct block *gen_uncond(compiler_state_t *, int); static inline struct block *gen_true(compiler_state_t *); static inline struct block *gen_false(compiler_state_t *); static struct block *gen_ether_linktype(compiler_state_t *, bpf_u_int32); static struct block *gen_ipnet_linktype(compiler_state_t *, bpf_u_int32); static struct block *gen_linux_sll_linktype(compiler_state_t *, bpf_u_int32); static struct slist *gen_load_pflog_llprefixlen(compiler_state_t *); static struct slist *gen_load_prism_llprefixlen(compiler_state_t *); static struct slist *gen_load_avs_llprefixlen(compiler_state_t *); static struct slist *gen_load_radiotap_llprefixlen(compiler_state_t *); static struct slist *gen_load_ppi_llprefixlen(compiler_state_t *); static void insert_compute_vloffsets(compiler_state_t *, struct block *); static struct slist *gen_abs_offset_varpart(compiler_state_t *, bpf_abs_offset *); static bpf_u_int32 ethertype_to_ppptype(bpf_u_int32); static struct block *gen_linktype(compiler_state_t *, bpf_u_int32); static struct block *gen_snap(compiler_state_t *, bpf_u_int32, bpf_u_int32); static struct block *gen_llc_linktype(compiler_state_t *, bpf_u_int32); static struct block *gen_hostop(compiler_state_t *, bpf_u_int32, bpf_u_int32, int, bpf_u_int32, u_int, u_int); #ifdef INET6 static struct block *gen_hostop6(compiler_state_t *, struct in6_addr *, struct in6_addr *, int, bpf_u_int32, u_int, u_int); #endif static struct block *gen_ahostop(compiler_state_t *, const u_char *, int); static struct block *gen_ehostop(compiler_state_t *, const u_char *, int); static struct block *gen_fhostop(compiler_state_t *, const u_char *, int); static struct block *gen_thostop(compiler_state_t *, const u_char *, int); static struct block *gen_wlanhostop(compiler_state_t *, const u_char *, int); static struct block *gen_ipfchostop(compiler_state_t *, const u_char *, int); static struct block *gen_dnhostop(compiler_state_t *, bpf_u_int32, int); static struct block *gen_mpls_linktype(compiler_state_t *, bpf_u_int32); static struct block *gen_host(compiler_state_t *, bpf_u_int32, bpf_u_int32, int, int, int); #ifdef INET6 static struct block *gen_host6(compiler_state_t *, struct in6_addr *, struct in6_addr *, int, int, int); #endif #ifndef INET6 static struct block *gen_gateway(compiler_state_t *, const u_char *, struct addrinfo *, int, int); #endif static struct block *gen_ipfrag(compiler_state_t *); static struct block *gen_portatom(compiler_state_t *, int, bpf_u_int32); static struct block *gen_portrangeatom(compiler_state_t *, u_int, bpf_u_int32, bpf_u_int32); static struct block *gen_portatom6(compiler_state_t *, int, bpf_u_int32); static struct block *gen_portrangeatom6(compiler_state_t *, u_int, bpf_u_int32, bpf_u_int32); static struct block *gen_portop(compiler_state_t *, u_int, u_int, int); static struct block *gen_port(compiler_state_t *, u_int, int, int); static struct block *gen_portrangeop(compiler_state_t *, u_int, u_int, bpf_u_int32, int); static struct block *gen_portrange(compiler_state_t *, u_int, u_int, int, int); struct block *gen_portop6(compiler_state_t *, u_int, u_int, int); static struct block *gen_port6(compiler_state_t *, u_int, int, int); static struct block *gen_portrangeop6(compiler_state_t *, u_int, u_int, bpf_u_int32, int); static struct block *gen_portrange6(compiler_state_t *, u_int, u_int, int, int); static int lookup_proto(compiler_state_t *, const char *, int); #if !defined(NO_PROTOCHAIN) static struct block *gen_protochain(compiler_state_t *, bpf_u_int32, int); #endif /* !defined(NO_PROTOCHAIN) */ static struct block *gen_proto(compiler_state_t *, bpf_u_int32, int, int); static struct slist *xfer_to_x(compiler_state_t *, struct arth *); static struct slist *xfer_to_a(compiler_state_t *, struct arth *); static struct block *gen_mac_multicast(compiler_state_t *, int); static struct block *gen_len(compiler_state_t *, int, int); static struct block *gen_check_802_11_data_frame(compiler_state_t *); static struct block *gen_geneve_ll_check(compiler_state_t *cstate); static struct block *gen_ppi_dlt_check(compiler_state_t *); static struct block *gen_atmfield_code_internal(compiler_state_t *, int, bpf_u_int32, int, int); static struct block *gen_atmtype_llc(compiler_state_t *); static struct block *gen_msg_abbrev(compiler_state_t *, int type); static void initchunks(compiler_state_t *cstate) { int i; for (i = 0; i < NCHUNKS; i++) { cstate->chunks[i].n_left = 0; cstate->chunks[i].m = NULL; } cstate->cur_chunk = 0; } static void * newchunk_nolongjmp(compiler_state_t *cstate, size_t n) { struct chunk *cp; int k; size_t size; #ifndef __NetBSD__ /* XXX Round up to nearest long. */ n = (n + sizeof(long) - 1) & ~(sizeof(long) - 1); #else /* XXX Round up to structure boundary. */ n = ALIGN(n); #endif cp = &cstate->chunks[cstate->cur_chunk]; if (n > cp->n_left) { ++cp; k = ++cstate->cur_chunk; if (k >= NCHUNKS) { bpf_set_error(cstate, "out of memory"); return (NULL); } size = CHUNK0SIZE << k; cp->m = (void *)malloc(size); if (cp->m == NULL) { bpf_set_error(cstate, "out of memory"); return (NULL); } memset((char *)cp->m, 0, size); cp->n_left = size; if (n > size) { bpf_set_error(cstate, "out of memory"); return (NULL); } } cp->n_left -= n; return (void *)((char *)cp->m + cp->n_left); } static void * newchunk(compiler_state_t *cstate, size_t n) { void *p; p = newchunk_nolongjmp(cstate, n); if (p == NULL) { longjmp(cstate->top_ctx, 1); /*NOTREACHED*/ } return (p); } static void freechunks(compiler_state_t *cstate) { int i; for (i = 0; i < NCHUNKS; ++i) if (cstate->chunks[i].m != NULL) free(cstate->chunks[i].m); } /* * A strdup whose allocations are freed after code generation is over. * This is used by the lexical analyzer, so it can't longjmp; it just * returns NULL on an allocation error, and the callers must check * for it. */ char * sdup(compiler_state_t *cstate, const char *s) { size_t n = strlen(s) + 1; char *cp = newchunk_nolongjmp(cstate, n); if (cp == NULL) return (NULL); pcap_strlcpy(cp, s, n); return (cp); } static inline struct block * new_block(compiler_state_t *cstate, int code) { struct block *p; p = (struct block *)newchunk(cstate, sizeof(*p)); p->s.code = code; p->head = p; return p; } static inline struct slist * new_stmt(compiler_state_t *cstate, int code) { struct slist *p; p = (struct slist *)newchunk(cstate, sizeof(*p)); p->s.code = code; return p; } static struct block * gen_retblk(compiler_state_t *cstate, int v) { struct block *b = new_block(cstate, BPF_RET|BPF_K); b->s.k = v; return b; } static inline PCAP_NORETURN_DEF void syntax(compiler_state_t *cstate) { bpf_error(cstate, "syntax error in filter expression"); } int pcap_compile(pcap_t *p, struct bpf_program *program, const char *buf, int optimize, bpf_u_int32 mask) { #ifdef _WIN32 static int done = 0; #endif compiler_state_t cstate; const char * volatile xbuf = buf; yyscan_t scanner = NULL; volatile YY_BUFFER_STATE in_buffer = NULL; u_int len; int rc; /* * If this pcap_t hasn't been activated, it doesn't have a * link-layer type, so we can't use it. */ if (!p->activated) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "not-yet-activated pcap_t passed to pcap_compile"); return (PCAP_ERROR); } #ifdef _WIN32 if (!done) pcap_wsockinit(); done = 1; #endif #ifdef ENABLE_REMOTE /* * If the device on which we're capturing need to be notified * that a new filter is being compiled, do so. * * This allows them to save a copy of it, in case, for example, * they're implementing a form of remote packet capture, and * want the remote machine to filter out the packets in which * it's sending the packets it's captured. * * XXX - the fact that we happen to be compiling a filter * doesn't necessarily mean we'll be installing it as the * filter for this pcap_t; we might be running it from userland * on captured packets to do packet classification. We really * need a better way of handling this, but this is all that * the WinPcap remote capture code did. */ if (p->save_current_filter_op != NULL) (p->save_current_filter_op)(p, buf); #endif initchunks(&cstate); cstate.no_optimize = 0; #ifdef INET6 cstate.ai = NULL; #endif cstate.e = NULL; cstate.ic.root = NULL; cstate.ic.cur_mark = 0; cstate.bpf_pcap = p; cstate.error_set = 0; init_regs(&cstate); cstate.netmask = mask; cstate.snaplen = pcap_snapshot(p); if (cstate.snaplen == 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "snaplen of 0 rejects all packets"); rc = PCAP_ERROR; goto quit; } if (pcap_lex_init(&scanner) != 0) pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE, errno, "can't initialize scanner"); in_buffer = pcap__scan_string(xbuf ? xbuf : "", scanner); /* * Associate the compiler state with the lexical analyzer * state. */ pcap_set_extra(&cstate, scanner); if (init_linktype(&cstate, p) == -1) { rc = PCAP_ERROR; goto quit; } if (pcap_parse(scanner, &cstate) != 0) { #ifdef INET6 if (cstate.ai != NULL) freeaddrinfo(cstate.ai); #endif if (cstate.e != NULL) free(cstate.e); rc = PCAP_ERROR; goto quit; } if (cstate.ic.root == NULL) { /* * Catch errors reported by gen_retblk(). */ if (setjmp(cstate.top_ctx)) { rc = PCAP_ERROR; goto quit; } cstate.ic.root = gen_retblk(&cstate, cstate.snaplen); } if (optimize && !cstate.no_optimize) { if (bpf_optimize(&cstate.ic, p->errbuf) == -1) { /* Failure */ rc = PCAP_ERROR; goto quit; } if (cstate.ic.root == NULL || (cstate.ic.root->s.code == (BPF_RET|BPF_K) && cstate.ic.root->s.k == 0)) { (void)snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "expression rejects all packets"); rc = PCAP_ERROR; goto quit; } } program->bf_insns = icode_to_fcode(&cstate.ic, cstate.ic.root, &len, p->errbuf); if (program->bf_insns == NULL) { /* Failure */ rc = PCAP_ERROR; goto quit; } program->bf_len = len; rc = 0; /* We're all okay */ quit: /* * Clean up everything for the lexical analyzer. */ if (in_buffer != NULL) pcap__delete_buffer(in_buffer, scanner); if (scanner != NULL) pcap_lex_destroy(scanner); /* * Clean up our own allocated memory. */ freechunks(&cstate); return (rc); } /* * entry point for using the compiler with no pcap open * pass in all the stuff that is needed explicitly instead. */ int pcap_compile_nopcap(int snaplen_arg, int linktype_arg, struct bpf_program *program, const char *buf, int optimize, bpf_u_int32 mask) { pcap_t *p; int ret; p = pcap_open_dead(linktype_arg, snaplen_arg); if (p == NULL) return (PCAP_ERROR); ret = pcap_compile(p, program, buf, optimize, mask); pcap_close(p); return (ret); } /* * Clean up a "struct bpf_program" by freeing all the memory allocated * in it. */ void pcap_freecode(struct bpf_program *program) { program->bf_len = 0; if (program->bf_insns != NULL) { free((char *)program->bf_insns); program->bf_insns = NULL; } } /* * Backpatch the blocks in 'list' to 'target'. The 'sense' field indicates * which of the jt and jf fields has been resolved and which is a pointer * back to another unresolved block (or nil). At least one of the fields * in each block is already resolved. */ static void backpatch(struct block *list, struct block *target) { struct block *next; while (list) { if (!list->sense) { next = JT(list); JT(list) = target; } else { next = JF(list); JF(list) = target; } list = next; } } /* * Merge the lists in b0 and b1, using the 'sense' field to indicate * which of jt and jf is the link. */ static void merge(struct block *b0, struct block *b1) { register struct block **p = &b0; /* Find end of list. */ while (*p) p = !((*p)->sense) ? &JT(*p) : &JF(*p); /* Concatenate the lists. */ *p = b1; } int finish_parse(compiler_state_t *cstate, struct block *p) { struct block *ppi_dlt_check; /* * Catch errors reported by us and routines below us, and return -1 * on an error. */ if (setjmp(cstate->top_ctx)) return (-1); /* * Insert before the statements of the first (root) block any * statements needed to load the lengths of any variable-length * headers into registers. * * XXX - a fancier strategy would be to insert those before the * statements of all blocks that use those lengths and that * have no predecessors that use them, so that we only compute * the lengths if we need them. There might be even better * approaches than that. * * However, those strategies would be more complicated, and * as we don't generate code to compute a length if the * program has no tests that use the length, and as most * tests will probably use those lengths, we would just * postpone computing the lengths so that it's not done * for tests that fail early, and it's not clear that's * worth the effort. */ insert_compute_vloffsets(cstate, p->head); /* * For DLT_PPI captures, generate a check of the per-packet * DLT value to make sure it's DLT_IEEE802_11. * * XXX - TurboCap cards use DLT_PPI for Ethernet. * Can we just define some DLT_ETHERNET_WITH_PHDR pseudo-header * with appropriate Ethernet information and use that rather * than using something such as DLT_PPI where you don't know * the link-layer header type until runtime, which, in the * general case, would force us to generate both Ethernet *and* * 802.11 code (*and* anything else for which PPI is used) * and choose between them early in the BPF program? */ ppi_dlt_check = gen_ppi_dlt_check(cstate); if (ppi_dlt_check != NULL) gen_and(ppi_dlt_check, p); backpatch(p, gen_retblk(cstate, cstate->snaplen)); p->sense = !p->sense; backpatch(p, gen_retblk(cstate, 0)); cstate->ic.root = p->head; return (0); } void gen_and(struct block *b0, struct block *b1) { backpatch(b0, b1->head); b0->sense = !b0->sense; b1->sense = !b1->sense; merge(b1, b0); b1->sense = !b1->sense; b1->head = b0->head; } void gen_or(struct block *b0, struct block *b1) { b0->sense = !b0->sense; backpatch(b0, b1->head); b0->sense = !b0->sense; merge(b1, b0); b1->head = b0->head; } void gen_not(struct block *b) { b->sense = !b->sense; } static struct block * gen_cmp(compiler_state_t *cstate, enum e_offrel offrel, u_int offset, u_int size, bpf_u_int32 v) { return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JEQ, 0, v); } static struct block * gen_cmp_gt(compiler_state_t *cstate, enum e_offrel offrel, u_int offset, u_int size, bpf_u_int32 v) { return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGT, 0, v); } static struct block * gen_cmp_ge(compiler_state_t *cstate, enum e_offrel offrel, u_int offset, u_int size, bpf_u_int32 v) { return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGE, 0, v); } static struct block * gen_cmp_lt(compiler_state_t *cstate, enum e_offrel offrel, u_int offset, u_int size, bpf_u_int32 v) { return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGE, 1, v); } static struct block * gen_cmp_le(compiler_state_t *cstate, enum e_offrel offrel, u_int offset, u_int size, bpf_u_int32 v) { return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGT, 1, v); } static struct block * gen_mcmp(compiler_state_t *cstate, enum e_offrel offrel, u_int offset, u_int size, bpf_u_int32 v, bpf_u_int32 mask) { return gen_ncmp(cstate, offrel, offset, size, mask, BPF_JEQ, 0, v); } static struct block * gen_bcmp(compiler_state_t *cstate, enum e_offrel offrel, u_int offset, u_int size, const u_char *v) { register struct block *b, *tmp; b = NULL; while (size >= 4) { register const u_char *p = &v[size - 4]; tmp = gen_cmp(cstate, offrel, offset + size - 4, BPF_W, EXTRACT_BE_U_4(p)); if (b != NULL) gen_and(b, tmp); b = tmp; size -= 4; } while (size >= 2) { register const u_char *p = &v[size - 2]; tmp = gen_cmp(cstate, offrel, offset + size - 2, BPF_H, EXTRACT_BE_U_2(p)); if (b != NULL) gen_and(b, tmp); b = tmp; size -= 2; } if (size > 0) { tmp = gen_cmp(cstate, offrel, offset, BPF_B, v[0]); if (b != NULL) gen_and(b, tmp); b = tmp; } return b; } /* * AND the field of size "size" at offset "offset" relative to the header * specified by "offrel" with "mask", and compare it with the value "v" * with the test specified by "jtype"; if "reverse" is true, the test * should test the opposite of "jtype". */ static struct block * gen_ncmp(compiler_state_t *cstate, enum e_offrel offrel, u_int offset, u_int size, bpf_u_int32 mask, int jtype, int reverse, bpf_u_int32 v) { struct slist *s, *s2; struct block *b; s = gen_load_a(cstate, offrel, offset, size); if (mask != 0xffffffff) { s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K); s2->s.k = mask; sappend(s, s2); } b = new_block(cstate, JMP(jtype)); b->stmts = s; b->s.k = v; if (reverse && (jtype == BPF_JGT || jtype == BPF_JGE)) gen_not(b); return b; } static int init_linktype(compiler_state_t *cstate, pcap_t *p) { cstate->pcap_fddipad = p->fddipad; /* * We start out with only one link-layer header. */ cstate->outermostlinktype = pcap_datalink(p); cstate->off_outermostlinkhdr.constant_part = 0; cstate->off_outermostlinkhdr.is_variable = 0; cstate->off_outermostlinkhdr.reg = -1; cstate->prevlinktype = cstate->outermostlinktype; cstate->off_prevlinkhdr.constant_part = 0; cstate->off_prevlinkhdr.is_variable = 0; cstate->off_prevlinkhdr.reg = -1; cstate->linktype = cstate->outermostlinktype; cstate->off_linkhdr.constant_part = 0; cstate->off_linkhdr.is_variable = 0; cstate->off_linkhdr.reg = -1; /* * XXX */ cstate->off_linkpl.constant_part = 0; cstate->off_linkpl.is_variable = 0; cstate->off_linkpl.reg = -1; cstate->off_linktype.constant_part = 0; cstate->off_linktype.is_variable = 0; cstate->off_linktype.reg = -1; /* * Assume it's not raw ATM with a pseudo-header, for now. */ cstate->is_atm = 0; cstate->off_vpi = OFFSET_NOT_SET; cstate->off_vci = OFFSET_NOT_SET; cstate->off_proto = OFFSET_NOT_SET; cstate->off_payload = OFFSET_NOT_SET; /* * And not Geneve. */ cstate->is_geneve = 0; /* * No variable length VLAN offset by default */ cstate->is_vlan_vloffset = 0; /* * And assume we're not doing SS7. */ cstate->off_li = OFFSET_NOT_SET; cstate->off_li_hsl = OFFSET_NOT_SET; cstate->off_sio = OFFSET_NOT_SET; cstate->off_opc = OFFSET_NOT_SET; cstate->off_dpc = OFFSET_NOT_SET; cstate->off_sls = OFFSET_NOT_SET; cstate->label_stack_depth = 0; cstate->vlan_stack_depth = 0; switch (cstate->linktype) { case DLT_ARCNET: cstate->off_linktype.constant_part = 2; cstate->off_linkpl.constant_part = 6; cstate->off_nl = 0; /* XXX in reality, variable! */ cstate->off_nl_nosnap = 0; /* no 802.2 LLC */ break; case DLT_ARCNET_LINUX: cstate->off_linktype.constant_part = 4; cstate->off_linkpl.constant_part = 8; cstate->off_nl = 0; /* XXX in reality, variable! */ cstate->off_nl_nosnap = 0; /* no 802.2 LLC */ break; case DLT_EN10MB: cstate->off_linktype.constant_part = 12; cstate->off_linkpl.constant_part = 14; /* Ethernet header length */ cstate->off_nl = 0; /* Ethernet II */ cstate->off_nl_nosnap = 3; /* 802.3+802.2 */ break; case DLT_SLIP: /* * SLIP doesn't have a link level type. The 16 byte * header is hacked into our SLIP driver. */ cstate->off_linktype.constant_part = OFFSET_NOT_SET; cstate->off_linkpl.constant_part = 16; cstate->off_nl = 0; cstate->off_nl_nosnap = 0; /* no 802.2 LLC */ break; case DLT_SLIP_BSDOS: /* XXX this may be the same as the DLT_PPP_BSDOS case */ cstate->off_linktype.constant_part = OFFSET_NOT_SET; /* XXX end */ cstate->off_linkpl.constant_part = 24; cstate->off_nl = 0; cstate->off_nl_nosnap = 0; /* no 802.2 LLC */ break; case DLT_NULL: case DLT_LOOP: cstate->off_linktype.constant_part = 0; cstate->off_linkpl.constant_part = 4; cstate->off_nl = 0; cstate->off_nl_nosnap = 0; /* no 802.2 LLC */ break; case DLT_ENC: cstate->off_linktype.constant_part = 0; cstate->off_linkpl.constant_part = 12; cstate->off_nl = 0; cstate->off_nl_nosnap = 0; /* no 802.2 LLC */ break; case DLT_PPP: case DLT_PPP_PPPD: case DLT_C_HDLC: /* BSD/OS Cisco HDLC */ case DLT_HDLC: /* NetBSD (Cisco) HDLC */ case DLT_PPP_SERIAL: /* NetBSD sync/async serial PPP */ cstate->off_linktype.constant_part = 2; /* skip HDLC-like framing */ cstate->off_linkpl.constant_part = 4; /* skip HDLC-like framing and protocol field */ cstate->off_nl = 0; cstate->off_nl_nosnap = 0; /* no 802.2 LLC */ break; case DLT_PPP_ETHER: /* * This does no include the Ethernet header, and * only covers session state. */ cstate->off_linktype.constant_part = 6; cstate->off_linkpl.constant_part = 8; cstate->off_nl = 0; cstate->off_nl_nosnap = 0; /* no 802.2 LLC */ break; case DLT_PPP_BSDOS: cstate->off_linktype.constant_part = 5; cstate->off_linkpl.constant_part = 24; cstate->off_nl = 0; cstate->off_nl_nosnap = 0; /* no 802.2 LLC */ break; case DLT_FDDI: /* * FDDI doesn't really have a link-level type field. * We set "off_linktype" to the offset of the LLC header. * * To check for Ethernet types, we assume that SSAP = SNAP * is being used and pick out the encapsulated Ethernet type. * XXX - should we generate code to check for SNAP? */ cstate->off_linktype.constant_part = 13; cstate->off_linktype.constant_part += cstate->pcap_fddipad; cstate->off_linkpl.constant_part = 13; /* FDDI MAC header length */ cstate->off_linkpl.constant_part += cstate->pcap_fddipad; cstate->off_nl = 8; /* 802.2+SNAP */ cstate->off_nl_nosnap = 3; /* 802.2 */ break; case DLT_IEEE802: /* * Token Ring doesn't really have a link-level type field. * We set "off_linktype" to the offset of the LLC header. * * To check for Ethernet types, we assume that SSAP = SNAP * is being used and pick out the encapsulated Ethernet type. * XXX - should we generate code to check for SNAP? * * XXX - the header is actually variable-length. * Some various Linux patched versions gave 38 * as "off_linktype" and 40 as "off_nl"; however, * if a token ring packet has *no* routing * information, i.e. is not source-routed, the correct * values are 20 and 22, as they are in the vanilla code. * * A packet is source-routed iff the uppermost bit * of the first byte of the source address, at an * offset of 8, has the uppermost bit set. If the * packet is source-routed, the total number of bytes * of routing information is 2 plus bits 0x1F00 of * the 16-bit value at an offset of 14 (shifted right * 8 - figure out which byte that is). */ cstate->off_linktype.constant_part = 14; cstate->off_linkpl.constant_part = 14; /* Token Ring MAC header length */ cstate->off_nl = 8; /* 802.2+SNAP */ cstate->off_nl_nosnap = 3; /* 802.2 */ break; case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO_AVS: case DLT_IEEE802_11_RADIO: cstate->off_linkhdr.is_variable = 1; /* Fall through, 802.11 doesn't have a variable link * prefix but is otherwise the same. */ /* FALLTHROUGH */ case DLT_IEEE802_11: /* * 802.11 doesn't really have a link-level type field. * We set "off_linktype.constant_part" to the offset of * the LLC header. * * To check for Ethernet types, we assume that SSAP = SNAP * is being used and pick out the encapsulated Ethernet type. * XXX - should we generate code to check for SNAP? * * We also handle variable-length radio headers here. * The Prism header is in theory variable-length, but in * practice it's always 144 bytes long. However, some * drivers on Linux use ARPHRD_IEEE80211_PRISM, but * sometimes or always supply an AVS header, so we * have to check whether the radio header is a Prism * header or an AVS header, so, in practice, it's * variable-length. */ cstate->off_linktype.constant_part = 24; cstate->off_linkpl.constant_part = 0; /* link-layer header is variable-length */ cstate->off_linkpl.is_variable = 1; cstate->off_nl = 8; /* 802.2+SNAP */ cstate->off_nl_nosnap = 3; /* 802.2 */ break; case DLT_PPI: /* * At the moment we treat PPI the same way that we treat * normal Radiotap encoded packets. The difference is in * the function that generates the code at the beginning * to compute the header length. Since this code generator * of PPI supports bare 802.11 encapsulation only (i.e. * the encapsulated DLT should be DLT_IEEE802_11) we * generate code to check for this too. */ cstate->off_linktype.constant_part = 24; cstate->off_linkpl.constant_part = 0; /* link-layer header is variable-length */ cstate->off_linkpl.is_variable = 1; cstate->off_linkhdr.is_variable = 1; cstate->off_nl = 8; /* 802.2+SNAP */ cstate->off_nl_nosnap = 3; /* 802.2 */ break; case DLT_ATM_RFC1483: case DLT_ATM_CLIP: /* Linux ATM defines this */ /* * assume routed, non-ISO PDUs * (i.e., LLC = 0xAA-AA-03, OUT = 0x00-00-00) * * XXX - what about ISO PDUs, e.g. CLNP, ISIS, ESIS, * or PPP with the PPP NLPID (e.g., PPPoA)? The * latter would presumably be treated the way PPPoE * should be, so you can do "pppoe and udp port 2049" * or "pppoa and tcp port 80" and have it check for * PPPo{A,E} and a PPP protocol of IP and.... */ cstate->off_linktype.constant_part = 0; cstate->off_linkpl.constant_part = 0; /* packet begins with LLC header */ cstate->off_nl = 8; /* 802.2+SNAP */ cstate->off_nl_nosnap = 3; /* 802.2 */ break; case DLT_SUNATM: /* * Full Frontal ATM; you get AALn PDUs with an ATM * pseudo-header. */ cstate->is_atm = 1; cstate->off_vpi = SUNATM_VPI_POS; cstate->off_vci = SUNATM_VCI_POS; cstate->off_proto = PROTO_POS; cstate->off_payload = SUNATM_PKT_BEGIN_POS; cstate->off_linktype.constant_part = cstate->off_payload; cstate->off_linkpl.constant_part = cstate->off_payload; /* if LLC-encapsulated */ cstate->off_nl = 8; /* 802.2+SNAP */ cstate->off_nl_nosnap = 3; /* 802.2 */ break; case DLT_RAW: case DLT_IPV4: case DLT_IPV6: cstate->off_linktype.constant_part = OFFSET_NOT_SET; cstate->off_linkpl.constant_part = 0; cstate->off_nl = 0; cstate->off_nl_nosnap = 0; /* no 802.2 LLC */ break; case DLT_LINUX_SLL: /* fake header for Linux cooked socket v1 */ cstate->off_linktype.constant_part = 14; cstate->off_linkpl.constant_part = 16; cstate->off_nl = 0; cstate->off_nl_nosnap = 0; /* no 802.2 LLC */ break; case DLT_LINUX_SLL2: /* fake header for Linux cooked socket v2 */ cstate->off_linktype.constant_part = 0; cstate->off_linkpl.constant_part = 20; cstate->off_nl = 0; cstate->off_nl_nosnap = 0; /* no 802.2 LLC */ break; case DLT_LTALK: /* * LocalTalk does have a 1-byte type field in the LLAP header, * but really it just indicates whether there is a "short" or * "long" DDP packet following. */ cstate->off_linktype.constant_part = OFFSET_NOT_SET; cstate->off_linkpl.constant_part = 0; cstate->off_nl = 0; cstate->off_nl_nosnap = 0; /* no 802.2 LLC */ break; case DLT_IP_OVER_FC: /* * RFC 2625 IP-over-Fibre-Channel doesn't really have a * link-level type field. We set "off_linktype" to the * offset of the LLC header. * * To check for Ethernet types, we assume that SSAP = SNAP * is being used and pick out the encapsulated Ethernet type. * XXX - should we generate code to check for SNAP? RFC * 2625 says SNAP should be used. */ cstate->off_linktype.constant_part = 16; cstate->off_linkpl.constant_part = 16; cstate->off_nl = 8; /* 802.2+SNAP */ cstate->off_nl_nosnap = 3; /* 802.2 */ break; case DLT_FRELAY: /* * XXX - we should set this to handle SNAP-encapsulated * frames (NLPID of 0x80). */ cstate->off_linktype.constant_part = OFFSET_NOT_SET; cstate->off_linkpl.constant_part = 0; cstate->off_nl = 0; cstate->off_nl_nosnap = 0; /* no 802.2 LLC */ break; /* * the only BPF-interesting FRF.16 frames are non-control frames; * Frame Relay has a variable length link-layer * so lets start with offset 4 for now and increments later on (FIXME); */ case DLT_MFR: cstate->off_linktype.constant_part = OFFSET_NOT_SET; cstate->off_linkpl.constant_part = 0; cstate->off_nl = 4; cstate->off_nl_nosnap = 0; /* XXX - for now -> no 802.2 LLC */ break; case DLT_APPLE_IP_OVER_IEEE1394: cstate->off_linktype.constant_part = 16; cstate->off_linkpl.constant_part = 18; cstate->off_nl = 0; cstate->off_nl_nosnap = 0; /* no 802.2 LLC */ break; case DLT_SYMANTEC_FIREWALL: cstate->off_linktype.constant_part = 6; cstate->off_linkpl.constant_part = 44; cstate->off_nl = 0; /* Ethernet II */ cstate->off_nl_nosnap = 0; /* XXX - what does it do with 802.3 packets? */ break; case DLT_PFLOG: cstate->off_linktype.constant_part = 0; cstate->off_linkpl.constant_part = 0; /* link-layer header is variable-length */ cstate->off_linkpl.is_variable = 1; cstate->off_nl = 0; cstate->off_nl_nosnap = 0; /* no 802.2 LLC */ break; case DLT_JUNIPER_MFR: case DLT_JUNIPER_MLFR: case DLT_JUNIPER_MLPPP: case DLT_JUNIPER_PPP: case DLT_JUNIPER_CHDLC: case DLT_JUNIPER_FRELAY: cstate->off_linktype.constant_part = 4; cstate->off_linkpl.constant_part = 4; cstate->off_nl = 0; cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */ break; case DLT_JUNIPER_ATM1: cstate->off_linktype.constant_part = 4; /* in reality variable between 4-8 */ cstate->off_linkpl.constant_part = 4; /* in reality variable between 4-8 */ cstate->off_nl = 0; cstate->off_nl_nosnap = 10; break; case DLT_JUNIPER_ATM2: cstate->off_linktype.constant_part = 8; /* in reality variable between 8-12 */ cstate->off_linkpl.constant_part = 8; /* in reality variable between 8-12 */ cstate->off_nl = 0; cstate->off_nl_nosnap = 10; break; /* frames captured on a Juniper PPPoE service PIC * contain raw ethernet frames */ case DLT_JUNIPER_PPPOE: case DLT_JUNIPER_ETHER: cstate->off_linkpl.constant_part = 14; cstate->off_linktype.constant_part = 16; cstate->off_nl = 18; /* Ethernet II */ cstate->off_nl_nosnap = 21; /* 802.3+802.2 */ break; case DLT_JUNIPER_PPPOE_ATM: cstate->off_linktype.constant_part = 4; cstate->off_linkpl.constant_part = 6; cstate->off_nl = 0; cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */ break; case DLT_JUNIPER_GGSN: cstate->off_linktype.constant_part = 6; cstate->off_linkpl.constant_part = 12; cstate->off_nl = 0; cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */ break; case DLT_JUNIPER_ES: cstate->off_linktype.constant_part = 6; cstate->off_linkpl.constant_part = OFFSET_NOT_SET; /* not really a network layer but raw IP addresses */ cstate->off_nl = OFFSET_NOT_SET; /* not really a network layer but raw IP addresses */ cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */ break; case DLT_JUNIPER_MONITOR: cstate->off_linktype.constant_part = 12; cstate->off_linkpl.constant_part = 12; cstate->off_nl = 0; /* raw IP/IP6 header */ cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */ break; case DLT_BACNET_MS_TP: cstate->off_linktype.constant_part = OFFSET_NOT_SET; cstate->off_linkpl.constant_part = OFFSET_NOT_SET; cstate->off_nl = OFFSET_NOT_SET; cstate->off_nl_nosnap = OFFSET_NOT_SET; break; case DLT_JUNIPER_SERVICES: cstate->off_linktype.constant_part = 12; cstate->off_linkpl.constant_part = OFFSET_NOT_SET; /* L3 proto location dep. on cookie type */ cstate->off_nl = OFFSET_NOT_SET; /* L3 proto location dep. on cookie type */ cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */ break; case DLT_JUNIPER_VP: cstate->off_linktype.constant_part = 18; cstate->off_linkpl.constant_part = OFFSET_NOT_SET; cstate->off_nl = OFFSET_NOT_SET; cstate->off_nl_nosnap = OFFSET_NOT_SET; break; case DLT_JUNIPER_ST: cstate->off_linktype.constant_part = 18; cstate->off_linkpl.constant_part = OFFSET_NOT_SET; cstate->off_nl = OFFSET_NOT_SET; cstate->off_nl_nosnap = OFFSET_NOT_SET; break; case DLT_JUNIPER_ISM: cstate->off_linktype.constant_part = 8; cstate->off_linkpl.constant_part = OFFSET_NOT_SET; cstate->off_nl = OFFSET_NOT_SET; cstate->off_nl_nosnap = OFFSET_NOT_SET; break; case DLT_JUNIPER_VS: case DLT_JUNIPER_SRX_E2E: case DLT_JUNIPER_FIBRECHANNEL: case DLT_JUNIPER_ATM_CEMIC: cstate->off_linktype.constant_part = 8; cstate->off_linkpl.constant_part = OFFSET_NOT_SET; cstate->off_nl = OFFSET_NOT_SET; cstate->off_nl_nosnap = OFFSET_NOT_SET; break; case DLT_MTP2: cstate->off_li = 2; cstate->off_li_hsl = 4; cstate->off_sio = 3; cstate->off_opc = 4; cstate->off_dpc = 4; cstate->off_sls = 7; cstate->off_linktype.constant_part = OFFSET_NOT_SET; cstate->off_linkpl.constant_part = OFFSET_NOT_SET; cstate->off_nl = OFFSET_NOT_SET; cstate->off_nl_nosnap = OFFSET_NOT_SET; break; case DLT_MTP2_WITH_PHDR: cstate->off_li = 6; cstate->off_li_hsl = 8; cstate->off_sio = 7; cstate->off_opc = 8; cstate->off_dpc = 8; cstate->off_sls = 11; cstate->off_linktype.constant_part = OFFSET_NOT_SET; cstate->off_linkpl.constant_part = OFFSET_NOT_SET; cstate->off_nl = OFFSET_NOT_SET; cstate->off_nl_nosnap = OFFSET_NOT_SET; break; case DLT_ERF: cstate->off_li = 22; cstate->off_li_hsl = 24; cstate->off_sio = 23; cstate->off_opc = 24; cstate->off_dpc = 24; cstate->off_sls = 27; cstate->off_linktype.constant_part = OFFSET_NOT_SET; cstate->off_linkpl.constant_part = OFFSET_NOT_SET; cstate->off_nl = OFFSET_NOT_SET; cstate->off_nl_nosnap = OFFSET_NOT_SET; break; case DLT_PFSYNC: cstate->off_linktype.constant_part = OFFSET_NOT_SET; cstate->off_linkpl.constant_part = 4; cstate->off_nl = 0; cstate->off_nl_nosnap = 0; break; case DLT_AX25_KISS: /* * Currently, only raw "link[N:M]" filtering is supported. */ cstate->off_linktype.constant_part = OFFSET_NOT_SET; /* variable, min 15, max 71 steps of 7 */ cstate->off_linkpl.constant_part = OFFSET_NOT_SET; cstate->off_nl = OFFSET_NOT_SET; /* variable, min 16, max 71 steps of 7 */ cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */ break; case DLT_IPNET: cstate->off_linktype.constant_part = 1; cstate->off_linkpl.constant_part = 24; /* ipnet header length */ cstate->off_nl = 0; cstate->off_nl_nosnap = OFFSET_NOT_SET; break; case DLT_NETANALYZER: cstate->off_linkhdr.constant_part = 4; /* Ethernet header is past 4-byte pseudo-header */ cstate->off_linktype.constant_part = cstate->off_linkhdr.constant_part + 12; cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 14; /* pseudo-header+Ethernet header length */ cstate->off_nl = 0; /* Ethernet II */ cstate->off_nl_nosnap = 3; /* 802.3+802.2 */ break; case DLT_NETANALYZER_TRANSPARENT: cstate->off_linkhdr.constant_part = 12; /* MAC header is past 4-byte pseudo-header, preamble, and SFD */ cstate->off_linktype.constant_part = cstate->off_linkhdr.constant_part + 12; cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 14; /* pseudo-header+preamble+SFD+Ethernet header length */ cstate->off_nl = 0; /* Ethernet II */ cstate->off_nl_nosnap = 3; /* 802.3+802.2 */ break; default: /* * For values in the range in which we've assigned new * DLT_ values, only raw "link[N:M]" filtering is supported. */ if (cstate->linktype >= DLT_MATCHING_MIN && cstate->linktype <= DLT_MATCHING_MAX) { cstate->off_linktype.constant_part = OFFSET_NOT_SET; cstate->off_linkpl.constant_part = OFFSET_NOT_SET; cstate->off_nl = OFFSET_NOT_SET; cstate->off_nl_nosnap = OFFSET_NOT_SET; } else { bpf_set_error(cstate, "unknown data link type %d (min %d, max %d)", cstate->linktype, DLT_MATCHING_MIN, DLT_MATCHING_MAX); return (-1); } break; } cstate->off_outermostlinkhdr = cstate->off_prevlinkhdr = cstate->off_linkhdr; return (0); } /* * Load a value relative to the specified absolute offset. */ static struct slist * gen_load_absoffsetrel(compiler_state_t *cstate, bpf_abs_offset *abs_offset, u_int offset, u_int size) { struct slist *s, *s2; s = gen_abs_offset_varpart(cstate, abs_offset); /* * If "s" is non-null, it has code to arrange that the X register * contains the variable part of the absolute offset, so we * generate a load relative to that, with an offset of * abs_offset->constant_part + offset. * * Otherwise, we can do an absolute load with an offset of * abs_offset->constant_part + offset. */ if (s != NULL) { /* * "s" points to a list of statements that puts the * variable part of the absolute offset into the X register. * Do an indirect load, to use the X register as an offset. */ s2 = new_stmt(cstate, BPF_LD|BPF_IND|size); s2->s.k = abs_offset->constant_part + offset; sappend(s, s2); } else { /* * There is no variable part of the absolute offset, so * just do an absolute load. */ s = new_stmt(cstate, BPF_LD|BPF_ABS|size); s->s.k = abs_offset->constant_part + offset; } return s; } /* * Load a value relative to the beginning of the specified header. */ static struct slist * gen_load_a(compiler_state_t *cstate, enum e_offrel offrel, u_int offset, u_int size) { struct slist *s, *s2; /* * Squelch warnings from compilers that *don't* assume that * offrel always has a valid enum value and therefore don't * assume that we'll always go through one of the case arms. * * If we have a default case, compilers that *do* assume that * will then complain about the default case code being * unreachable. * * Damned if you do, damned if you don't. */ s = NULL; switch (offrel) { case OR_PACKET: s = new_stmt(cstate, BPF_LD|BPF_ABS|size); s->s.k = offset; break; case OR_LINKHDR: s = gen_load_absoffsetrel(cstate, &cstate->off_linkhdr, offset, size); break; case OR_PREVLINKHDR: s = gen_load_absoffsetrel(cstate, &cstate->off_prevlinkhdr, offset, size); break; case OR_LLC: s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, offset, size); break; case OR_PREVMPLSHDR: s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl - 4 + offset, size); break; case OR_LINKPL: s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl + offset, size); break; case OR_LINKPL_NOSNAP: s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl_nosnap + offset, size); break; case OR_LINKTYPE: s = gen_load_absoffsetrel(cstate, &cstate->off_linktype, offset, size); break; case OR_TRAN_IPV4: /* * Load the X register with the length of the IPv4 header * (plus the offset of the link-layer header, if it's * preceded by a variable-length header such as a radio * header), in bytes. */ s = gen_loadx_iphdrlen(cstate); /* * Load the item at {offset of the link-layer payload} + * {offset, relative to the start of the link-layer * paylod, of the IPv4 header} + {length of the IPv4 header} + * {specified offset}. * * If the offset of the link-layer payload is variable, * the variable part of that offset is included in the * value in the X register, and we include the constant * part in the offset of the load. */ s2 = new_stmt(cstate, BPF_LD|BPF_IND|size); s2->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + offset; sappend(s, s2); break; case OR_TRAN_IPV6: s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl + 40 + offset, size); break; } return s; } /* * Generate code to load into the X register the sum of the length of * the IPv4 header and the variable part of the offset of the link-layer * payload. */ static struct slist * gen_loadx_iphdrlen(compiler_state_t *cstate) { struct slist *s, *s2; s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl); if (s != NULL) { /* * The offset of the link-layer payload has a variable * part. "s" points to a list of statements that put * the variable part of that offset into the X register. * * The 4*([k]&0xf) addressing mode can't be used, as we * don't have a constant offset, so we have to load the * value in question into the A register and add to it * the value from the X register. */ s2 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B); s2->s.k = cstate->off_linkpl.constant_part + cstate->off_nl; sappend(s, s2); s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K); s2->s.k = 0xf; sappend(s, s2); s2 = new_stmt(cstate, BPF_ALU|BPF_LSH|BPF_K); s2->s.k = 2; sappend(s, s2); /* * The A register now contains the length of the IP header. * We need to add to it the variable part of the offset of * the link-layer payload, which is still in the X * register, and move the result into the X register. */ sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X)); sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX)); } else { /* * The offset of the link-layer payload is a constant, * so no code was generated to load the (non-existent) * variable part of that offset. * * This means we can use the 4*([k]&0xf) addressing * mode. Load the length of the IPv4 header, which * is at an offset of cstate->off_nl from the beginning of * the link-layer payload, and thus at an offset of * cstate->off_linkpl.constant_part + cstate->off_nl from the beginning * of the raw packet data, using that addressing mode. */ s = new_stmt(cstate, BPF_LDX|BPF_MSH|BPF_B); s->s.k = cstate->off_linkpl.constant_part + cstate->off_nl; } return s; } static struct block * gen_uncond(compiler_state_t *cstate, int rsense) { struct block *b; struct slist *s; s = new_stmt(cstate, BPF_LD|BPF_IMM); s->s.k = !rsense; b = new_block(cstate, JMP(BPF_JEQ)); b->stmts = s; return b; } static inline struct block * gen_true(compiler_state_t *cstate) { return gen_uncond(cstate, 1); } static inline struct block * gen_false(compiler_state_t *cstate) { return gen_uncond(cstate, 0); } /* * Byte-swap a 32-bit number. * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on * big-endian platforms.) */ #define SWAPLONG(y) \ ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff)) /* * Generate code to match a particular packet type. * * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP * value, if <= ETHERMTU. We use that to determine whether to * match the type/length field or to check the type/length field for * a value <= ETHERMTU to see whether it's a type field and then do * the appropriate test. */ static struct block * gen_ether_linktype(compiler_state_t *cstate, bpf_u_int32 ll_proto) { struct block *b0, *b1; switch (ll_proto) { case LLCSAP_ISONS: case LLCSAP_IP: case LLCSAP_NETBEUI: /* * OSI protocols and NetBEUI always use 802.2 encapsulation, * so we check the DSAP and SSAP. * * LLCSAP_IP checks for IP-over-802.2, rather * than IP-over-Ethernet or IP-over-SNAP. * * XXX - should we check both the DSAP and the * SSAP, like this, or should we check just the * DSAP, as we do for other types <= ETHERMTU * (i.e., other SAP values)? */ b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU); gen_not(b0); b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, (ll_proto << 8) | ll_proto); gen_and(b0, b1); return b1; case LLCSAP_IPX: /* * Check for; * * Ethernet_II frames, which are Ethernet * frames with a frame type of ETHERTYPE_IPX; * * Ethernet_802.3 frames, which are 802.3 * frames (i.e., the type/length field is * a length field, <= ETHERMTU, rather than * a type field) with the first two bytes * after the Ethernet/802.3 header being * 0xFFFF; * * Ethernet_802.2 frames, which are 802.3 * frames with an 802.2 LLC header and * with the IPX LSAP as the DSAP in the LLC * header; * * Ethernet_SNAP frames, which are 802.3 * frames with an LLC header and a SNAP * header and with an OUI of 0x000000 * (encapsulated Ethernet) and a protocol * ID of ETHERTYPE_IPX in the SNAP header. * * XXX - should we generate the same code both * for tests for LLCSAP_IPX and for ETHERTYPE_IPX? */ /* * This generates code to check both for the * IPX LSAP (Ethernet_802.2) and for Ethernet_802.3. */ b0 = gen_cmp(cstate, OR_LLC, 0, BPF_B, LLCSAP_IPX); b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, 0xFFFF); gen_or(b0, b1); /* * Now we add code to check for SNAP frames with * ETHERTYPE_IPX, i.e. Ethernet_SNAP. */ b0 = gen_snap(cstate, 0x000000, ETHERTYPE_IPX); gen_or(b0, b1); /* * Now we generate code to check for 802.3 * frames in general. */ b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU); gen_not(b0); /* * Now add the check for 802.3 frames before the * check for Ethernet_802.2 and Ethernet_802.3, * as those checks should only be done on 802.3 * frames, not on Ethernet frames. */ gen_and(b0, b1); /* * Now add the check for Ethernet_II frames, and * do that before checking for the other frame * types. */ b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, ETHERTYPE_IPX); gen_or(b0, b1); return b1; case ETHERTYPE_ATALK: case ETHERTYPE_AARP: /* * EtherTalk (AppleTalk protocols on Ethernet link * layer) may use 802.2 encapsulation. */ /* * Check for 802.2 encapsulation (EtherTalk phase 2?); * we check for an Ethernet type field less than * 1500, which means it's an 802.3 length field. */ b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU); gen_not(b0); /* * 802.2-encapsulated ETHERTYPE_ATALK packets are * SNAP packets with an organization code of * 0x080007 (Apple, for Appletalk) and a protocol * type of ETHERTYPE_ATALK (Appletalk). * * 802.2-encapsulated ETHERTYPE_AARP packets are * SNAP packets with an organization code of * 0x000000 (encapsulated Ethernet) and a protocol * type of ETHERTYPE_AARP (Appletalk ARP). */ if (ll_proto == ETHERTYPE_ATALK) b1 = gen_snap(cstate, 0x080007, ETHERTYPE_ATALK); else /* ll_proto == ETHERTYPE_AARP */ b1 = gen_snap(cstate, 0x000000, ETHERTYPE_AARP); gen_and(b0, b1); /* * Check for Ethernet encapsulation (Ethertalk * phase 1?); we just check for the Ethernet * protocol type. */ b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, ll_proto); gen_or(b0, b1); return b1; default: if (ll_proto <= ETHERMTU) { /* * This is an LLC SAP value, so the frames * that match would be 802.2 frames. * Check that the frame is an 802.2 frame * (i.e., that the length/type field is * a length field, <= ETHERMTU) and * then check the DSAP. */ b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU); gen_not(b0); b1 = gen_cmp(cstate, OR_LINKTYPE, 2, BPF_B, ll_proto); gen_and(b0, b1); return b1; } else { /* * This is an Ethernet type, so compare * the length/type field with it (if * the frame is an 802.2 frame, the length * field will be <= ETHERMTU, and, as * "ll_proto" is > ETHERMTU, this test * will fail and the frame won't match, * which is what we want). */ return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, ll_proto); } } } static struct block * gen_loopback_linktype(compiler_state_t *cstate, bpf_u_int32 ll_proto) { /* * For DLT_NULL, the link-layer header is a 32-bit word * containing an AF_ value in *host* byte order, and for * DLT_ENC, the link-layer header begins with a 32-bit * word containing an AF_ value in host byte order. * * In addition, if we're reading a saved capture file, * the host byte order in the capture may not be the * same as the host byte order on this machine. * * For DLT_LOOP, the link-layer header is a 32-bit * word containing an AF_ value in *network* byte order. */ if (cstate->linktype == DLT_NULL || cstate->linktype == DLT_ENC) { /* * The AF_ value is in host byte order, but the BPF * interpreter will convert it to network byte order. * * If this is a save file, and it's from a machine * with the opposite byte order to ours, we byte-swap * the AF_ value. * * Then we run it through "htonl()", and generate * code to compare against the result. */ if (cstate->bpf_pcap->rfile != NULL && cstate->bpf_pcap->swapped) ll_proto = SWAPLONG(ll_proto); ll_proto = htonl(ll_proto); } return (gen_cmp(cstate, OR_LINKHDR, 0, BPF_W, ll_proto)); } /* * "proto" is an Ethernet type value and for IPNET, if it is not IPv4 * or IPv6 then we have an error. */ static struct block * gen_ipnet_linktype(compiler_state_t *cstate, bpf_u_int32 ll_proto) { switch (ll_proto) { case ETHERTYPE_IP: return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B, IPH_AF_INET); /*NOTREACHED*/ case ETHERTYPE_IPV6: return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B, IPH_AF_INET6); /*NOTREACHED*/ default: break; } return gen_false(cstate); } /* * Generate code to match a particular packet type. * * "ll_proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP * value, if <= ETHERMTU. We use that to determine whether to * match the type field or to check the type field for the special * LINUX_SLL_P_802_2 value and then do the appropriate test. */ static struct block * gen_linux_sll_linktype(compiler_state_t *cstate, bpf_u_int32 ll_proto) { struct block *b0, *b1; switch (ll_proto) { case LLCSAP_ISONS: case LLCSAP_IP: case LLCSAP_NETBEUI: /* * OSI protocols and NetBEUI always use 802.2 encapsulation, * so we check the DSAP and SSAP. * * LLCSAP_IP checks for IP-over-802.2, rather * than IP-over-Ethernet or IP-over-SNAP. * * XXX - should we check both the DSAP and the * SSAP, like this, or should we check just the * DSAP, as we do for other types <= ETHERMTU * (i.e., other SAP values)? */ b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2); b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, (ll_proto << 8) | ll_proto); gen_and(b0, b1); return b1; case LLCSAP_IPX: /* * Ethernet_II frames, which are Ethernet * frames with a frame type of ETHERTYPE_IPX; * * Ethernet_802.3 frames, which have a frame * type of LINUX_SLL_P_802_3; * * Ethernet_802.2 frames, which are 802.3 * frames with an 802.2 LLC header (i.e, have * a frame type of LINUX_SLL_P_802_2) and * with the IPX LSAP as the DSAP in the LLC * header; * * Ethernet_SNAP frames, which are 802.3 * frames with an LLC header and a SNAP * header and with an OUI of 0x000000 * (encapsulated Ethernet) and a protocol * ID of ETHERTYPE_IPX in the SNAP header. * * First, do the checks on LINUX_SLL_P_802_2 * frames; generate the check for either * Ethernet_802.2 or Ethernet_SNAP frames, and * then put a check for LINUX_SLL_P_802_2 frames * before it. */ b0 = gen_cmp(cstate, OR_LLC, 0, BPF_B, LLCSAP_IPX); b1 = gen_snap(cstate, 0x000000, ETHERTYPE_IPX); gen_or(b0, b1); b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2); gen_and(b0, b1); /* * Now check for 802.3 frames and OR that with * the previous test. */ b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_3); gen_or(b0, b1); /* * Now add the check for Ethernet_II frames, and * do that before checking for the other frame * types. */ b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, ETHERTYPE_IPX); gen_or(b0, b1); return b1; case ETHERTYPE_ATALK: case ETHERTYPE_AARP: /* * EtherTalk (AppleTalk protocols on Ethernet link * layer) may use 802.2 encapsulation. */ /* * Check for 802.2 encapsulation (EtherTalk phase 2?); * we check for the 802.2 protocol type in the * "Ethernet type" field. */ b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2); /* * 802.2-encapsulated ETHERTYPE_ATALK packets are * SNAP packets with an organization code of * 0x080007 (Apple, for Appletalk) and a protocol * type of ETHERTYPE_ATALK (Appletalk). * * 802.2-encapsulated ETHERTYPE_AARP packets are * SNAP packets with an organization code of * 0x000000 (encapsulated Ethernet) and a protocol * type of ETHERTYPE_AARP (Appletalk ARP). */ if (ll_proto == ETHERTYPE_ATALK) b1 = gen_snap(cstate, 0x080007, ETHERTYPE_ATALK); else /* ll_proto == ETHERTYPE_AARP */ b1 = gen_snap(cstate, 0x000000, ETHERTYPE_AARP); gen_and(b0, b1); /* * Check for Ethernet encapsulation (Ethertalk * phase 1?); we just check for the Ethernet * protocol type. */ b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, ll_proto); gen_or(b0, b1); return b1; default: if (ll_proto <= ETHERMTU) { /* * This is an LLC SAP value, so the frames * that match would be 802.2 frames. * Check for the 802.2 protocol type * in the "Ethernet type" field, and * then check the DSAP. */ b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2); b1 = gen_cmp(cstate, OR_LINKHDR, cstate->off_linkpl.constant_part, BPF_B, ll_proto); gen_and(b0, b1); return b1; } else { /* * This is an Ethernet type, so compare * the length/type field with it (if * the frame is an 802.2 frame, the length * field will be <= ETHERMTU, and, as * "ll_proto" is > ETHERMTU, this test * will fail and the frame won't match, * which is what we want). */ return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, ll_proto); } } } /* * Load a value relative to the beginning of the link-layer header after the * pflog header. */ static struct slist * gen_load_pflog_llprefixlen(compiler_state_t *cstate) { struct slist *s1, *s2; /* * Generate code to load the length of the pflog header into * the register assigned to hold that length, if one has been * assigned. (If one hasn't been assigned, no code we've * generated uses that prefix, so we don't need to generate any * code to load it.) */ if (cstate->off_linkpl.reg != -1) { /* * The length is in the first byte of the header. */ s1 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS); s1->s.k = 0; /* * Round it up to a multiple of 4. * Add 3, and clear the lower 2 bits. */ s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K); s2->s.k = 3; sappend(s1, s2); s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K); s2->s.k = 0xfffffffc; sappend(s1, s2); /* * Now allocate a register to hold that value and store * it. */ s2 = new_stmt(cstate, BPF_ST); s2->s.k = cstate->off_linkpl.reg; sappend(s1, s2); /* * Now move it into the X register. */ s2 = new_stmt(cstate, BPF_MISC|BPF_TAX); sappend(s1, s2); return (s1); } else return (NULL); } static struct slist * gen_load_prism_llprefixlen(compiler_state_t *cstate) { struct slist *s1, *s2; struct slist *sjeq_avs_cookie; struct slist *sjcommon; /* * This code is not compatible with the optimizer, as * we are generating jmp instructions within a normal * slist of instructions */ cstate->no_optimize = 1; /* * Generate code to load the length of the radio header into * the register assigned to hold that length, if one has been * assigned. (If one hasn't been assigned, no code we've * generated uses that prefix, so we don't need to generate any * code to load it.) * * Some Linux drivers use ARPHRD_IEEE80211_PRISM but sometimes * or always use the AVS header rather than the Prism header. * We load a 4-byte big-endian value at the beginning of the * raw packet data, and see whether, when masked with 0xFFFFF000, * it's equal to 0x80211000. If so, that indicates that it's * an AVS header (the masked-out bits are the version number). * Otherwise, it's a Prism header. * * XXX - the Prism header is also, in theory, variable-length, * but no known software generates headers that aren't 144 * bytes long. */ if (cstate->off_linkhdr.reg != -1) { /* * Load the cookie. */ s1 = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS); s1->s.k = 0; /* * AND it with 0xFFFFF000. */ s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K); s2->s.k = 0xFFFFF000; sappend(s1, s2); /* * Compare with 0x80211000. */ sjeq_avs_cookie = new_stmt(cstate, JMP(BPF_JEQ)); sjeq_avs_cookie->s.k = 0x80211000; sappend(s1, sjeq_avs_cookie); /* * If it's AVS: * * The 4 bytes at an offset of 4 from the beginning of * the AVS header are the length of the AVS header. * That field is big-endian. */ s2 = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS); s2->s.k = 4; sappend(s1, s2); sjeq_avs_cookie->s.jt = s2; /* * Now jump to the code to allocate a register * into which to save the header length and * store the length there. (The "jump always" * instruction needs to have the k field set; * it's added to the PC, so, as we're jumping * over a single instruction, it should be 1.) */ sjcommon = new_stmt(cstate, JMP(BPF_JA)); sjcommon->s.k = 1; sappend(s1, sjcommon); /* * Now for the code that handles the Prism header. * Just load the length of the Prism header (144) * into the A register. Have the test for an AVS * header branch here if we don't have an AVS header. */ s2 = new_stmt(cstate, BPF_LD|BPF_W|BPF_IMM); s2->s.k = 144; sappend(s1, s2); sjeq_avs_cookie->s.jf = s2; /* * Now allocate a register to hold that value and store * it. The code for the AVS header will jump here after * loading the length of the AVS header. */ s2 = new_stmt(cstate, BPF_ST); s2->s.k = cstate->off_linkhdr.reg; sappend(s1, s2); sjcommon->s.jf = s2; /* * Now move it into the X register. */ s2 = new_stmt(cstate, BPF_MISC|BPF_TAX); sappend(s1, s2); return (s1); } else return (NULL); } static struct slist * gen_load_avs_llprefixlen(compiler_state_t *cstate) { struct slist *s1, *s2; /* * Generate code to load the length of the AVS header into * the register assigned to hold that length, if one has been * assigned. (If one hasn't been assigned, no code we've * generated uses that prefix, so we don't need to generate any * code to load it.) */ if (cstate->off_linkhdr.reg != -1) { /* * The 4 bytes at an offset of 4 from the beginning of * the AVS header are the length of the AVS header. * That field is big-endian. */ s1 = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS); s1->s.k = 4; /* * Now allocate a register to hold that value and store * it. */ s2 = new_stmt(cstate, BPF_ST); s2->s.k = cstate->off_linkhdr.reg; sappend(s1, s2); /* * Now move it into the X register. */ s2 = new_stmt(cstate, BPF_MISC|BPF_TAX); sappend(s1, s2); return (s1); } else return (NULL); } static struct slist * gen_load_radiotap_llprefixlen(compiler_state_t *cstate) { struct slist *s1, *s2; /* * Generate code to load the length of the radiotap header into * the register assigned to hold that length, if one has been * assigned. (If one hasn't been assigned, no code we've * generated uses that prefix, so we don't need to generate any * code to load it.) */ if (cstate->off_linkhdr.reg != -1) { /* * The 2 bytes at offsets of 2 and 3 from the beginning * of the radiotap header are the length of the radiotap * header; unfortunately, it's little-endian, so we have * to load it a byte at a time and construct the value. */ /* * Load the high-order byte, at an offset of 3, shift it * left a byte, and put the result in the X register. */ s1 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS); s1->s.k = 3; s2 = new_stmt(cstate, BPF_ALU|BPF_LSH|BPF_K); sappend(s1, s2); s2->s.k = 8; s2 = new_stmt(cstate, BPF_MISC|BPF_TAX); sappend(s1, s2); /* * Load the next byte, at an offset of 2, and OR the * value from the X register into it. */ s2 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS); sappend(s1, s2); s2->s.k = 2; s2 = new_stmt(cstate, BPF_ALU|BPF_OR|BPF_X); sappend(s1, s2); /* * Now allocate a register to hold that value and store * it. */ s2 = new_stmt(cstate, BPF_ST); s2->s.k = cstate->off_linkhdr.reg; sappend(s1, s2); /* * Now move it into the X register. */ s2 = new_stmt(cstate, BPF_MISC|BPF_TAX); sappend(s1, s2); return (s1); } else return (NULL); } /* * At the moment we treat PPI as normal Radiotap encoded * packets. The difference is in the function that generates * the code at the beginning to compute the header length. * Since this code generator of PPI supports bare 802.11 * encapsulation only (i.e. the encapsulated DLT should be * DLT_IEEE802_11) we generate code to check for this too; * that's done in finish_parse(). */ static struct slist * gen_load_ppi_llprefixlen(compiler_state_t *cstate) { struct slist *s1, *s2; /* * Generate code to load the length of the radiotap header * into the register assigned to hold that length, if one has * been assigned. */ if (cstate->off_linkhdr.reg != -1) { /* * The 2 bytes at offsets of 2 and 3 from the beginning * of the radiotap header are the length of the radiotap * header; unfortunately, it's little-endian, so we have * to load it a byte at a time and construct the value. */ /* * Load the high-order byte, at an offset of 3, shift it * left a byte, and put the result in the X register. */ s1 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS); s1->s.k = 3; s2 = new_stmt(cstate, BPF_ALU|BPF_LSH|BPF_K); sappend(s1, s2); s2->s.k = 8; s2 = new_stmt(cstate, BPF_MISC|BPF_TAX); sappend(s1, s2); /* * Load the next byte, at an offset of 2, and OR the * value from the X register into it. */ s2 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS); sappend(s1, s2); s2->s.k = 2; s2 = new_stmt(cstate, BPF_ALU|BPF_OR|BPF_X); sappend(s1, s2); /* * Now allocate a register to hold that value and store * it. */ s2 = new_stmt(cstate, BPF_ST); s2->s.k = cstate->off_linkhdr.reg; sappend(s1, s2); /* * Now move it into the X register. */ s2 = new_stmt(cstate, BPF_MISC|BPF_TAX); sappend(s1, s2); return (s1); } else return (NULL); } /* * Load a value relative to the beginning of the link-layer header after the 802.11 * header, i.e. LLC_SNAP. * The link-layer header doesn't necessarily begin at the beginning * of the packet data; there might be a variable-length prefix containing * radio information. */ static struct slist * gen_load_802_11_header_len(compiler_state_t *cstate, struct slist *s, struct slist *snext) { struct slist *s2; struct slist *sjset_data_frame_1; struct slist *sjset_data_frame_2; struct slist *sjset_qos; struct slist *sjset_radiotap_flags_present; struct slist *sjset_radiotap_ext_present; struct slist *sjset_radiotap_tsft_present; struct slist *sjset_tsft_datapad, *sjset_notsft_datapad; struct slist *s_roundup; if (cstate->off_linkpl.reg == -1) { /* * No register has been assigned to the offset of * the link-layer payload, which means nobody needs * it; don't bother computing it - just return * what we already have. */ return (s); } /* * This code is not compatible with the optimizer, as * we are generating jmp instructions within a normal * slist of instructions */ cstate->no_optimize = 1; /* * If "s" is non-null, it has code to arrange that the X register * contains the length of the prefix preceding the link-layer * header. * * Otherwise, the length of the prefix preceding the link-layer * header is "off_outermostlinkhdr.constant_part". */ if (s == NULL) { /* * There is no variable-length header preceding the * link-layer header. * * Load the length of the fixed-length prefix preceding * the link-layer header (if any) into the X register, * and store it in the cstate->off_linkpl.reg register. * That length is off_outermostlinkhdr.constant_part. */ s = new_stmt(cstate, BPF_LDX|BPF_IMM); s->s.k = cstate->off_outermostlinkhdr.constant_part; } /* * The X register contains the offset of the beginning of the * link-layer header; add 24, which is the minimum length * of the MAC header for a data frame, to that, and store it * in cstate->off_linkpl.reg, and then load the Frame Control field, * which is at the offset in the X register, with an indexed load. */ s2 = new_stmt(cstate, BPF_MISC|BPF_TXA); sappend(s, s2); s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K); s2->s.k = 24; sappend(s, s2); s2 = new_stmt(cstate, BPF_ST); s2->s.k = cstate->off_linkpl.reg; sappend(s, s2); s2 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B); s2->s.k = 0; sappend(s, s2); /* * Check the Frame Control field to see if this is a data frame; * a data frame has the 0x08 bit (b3) in that field set and the * 0x04 bit (b2) clear. */ sjset_data_frame_1 = new_stmt(cstate, JMP(BPF_JSET)); sjset_data_frame_1->s.k = 0x08; sappend(s, sjset_data_frame_1); /* * If b3 is set, test b2, otherwise go to the first statement of * the rest of the program. */ sjset_data_frame_1->s.jt = sjset_data_frame_2 = new_stmt(cstate, JMP(BPF_JSET)); sjset_data_frame_2->s.k = 0x04; sappend(s, sjset_data_frame_2); sjset_data_frame_1->s.jf = snext; /* * If b2 is not set, this is a data frame; test the QoS bit. * Otherwise, go to the first statement of the rest of the * program. */ sjset_data_frame_2->s.jt = snext; sjset_data_frame_2->s.jf = sjset_qos = new_stmt(cstate, JMP(BPF_JSET)); sjset_qos->s.k = 0x80; /* QoS bit */ sappend(s, sjset_qos); /* * If it's set, add 2 to cstate->off_linkpl.reg, to skip the QoS * field. * Otherwise, go to the first statement of the rest of the * program. */ sjset_qos->s.jt = s2 = new_stmt(cstate, BPF_LD|BPF_MEM); s2->s.k = cstate->off_linkpl.reg; sappend(s, s2); s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_IMM); s2->s.k = 2; sappend(s, s2); s2 = new_stmt(cstate, BPF_ST); s2->s.k = cstate->off_linkpl.reg; sappend(s, s2); /* * If we have a radiotap header, look at it to see whether * there's Atheros padding between the MAC-layer header * and the payload. * * Note: all of the fields in the radiotap header are * little-endian, so we byte-swap all of the values * we test against, as they will be loaded as big-endian * values. * * XXX - in the general case, we would have to scan through * *all* the presence bits, if there's more than one word of * presence bits. That would require a loop, meaning that * we wouldn't be able to run the filter in the kernel. * * We assume here that the Atheros adapters that insert the * annoying padding don't have multiple antennae and therefore * do not generate radiotap headers with multiple presence words. */ if (cstate->linktype == DLT_IEEE802_11_RADIO) { /* * Is the IEEE80211_RADIOTAP_FLAGS bit (0x0000002) set * in the first presence flag word? */ sjset_qos->s.jf = s2 = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_W); s2->s.k = 4; sappend(s, s2); sjset_radiotap_flags_present = new_stmt(cstate, JMP(BPF_JSET)); sjset_radiotap_flags_present->s.k = SWAPLONG(0x00000002); sappend(s, sjset_radiotap_flags_present); /* * If not, skip all of this. */ sjset_radiotap_flags_present->s.jf = snext; /* * Otherwise, is the "extension" bit set in that word? */ sjset_radiotap_ext_present = new_stmt(cstate, JMP(BPF_JSET)); sjset_radiotap_ext_present->s.k = SWAPLONG(0x80000000); sappend(s, sjset_radiotap_ext_present); sjset_radiotap_flags_present->s.jt = sjset_radiotap_ext_present; /* * If so, skip all of this. */ sjset_radiotap_ext_present->s.jt = snext; /* * Otherwise, is the IEEE80211_RADIOTAP_TSFT bit set? */ sjset_radiotap_tsft_present = new_stmt(cstate, JMP(BPF_JSET)); sjset_radiotap_tsft_present->s.k = SWAPLONG(0x00000001); sappend(s, sjset_radiotap_tsft_present); sjset_radiotap_ext_present->s.jf = sjset_radiotap_tsft_present; /* * If IEEE80211_RADIOTAP_TSFT is set, the flags field is * at an offset of 16 from the beginning of the raw packet * data (8 bytes for the radiotap header and 8 bytes for * the TSFT field). * * Test whether the IEEE80211_RADIOTAP_F_DATAPAD bit (0x20) * is set. */ s2 = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B); s2->s.k = 16; sappend(s, s2); sjset_radiotap_tsft_present->s.jt = s2; sjset_tsft_datapad = new_stmt(cstate, JMP(BPF_JSET)); sjset_tsft_datapad->s.k = 0x20; sappend(s, sjset_tsft_datapad); /* * If IEEE80211_RADIOTAP_TSFT is not set, the flags field is * at an offset of 8 from the beginning of the raw packet * data (8 bytes for the radiotap header). * * Test whether the IEEE80211_RADIOTAP_F_DATAPAD bit (0x20) * is set. */ s2 = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B); s2->s.k = 8; sappend(s, s2); sjset_radiotap_tsft_present->s.jf = s2; sjset_notsft_datapad = new_stmt(cstate, JMP(BPF_JSET)); sjset_notsft_datapad->s.k = 0x20; sappend(s, sjset_notsft_datapad); /* * In either case, if IEEE80211_RADIOTAP_F_DATAPAD is * set, round the length of the 802.11 header to * a multiple of 4. Do that by adding 3 and then * dividing by and multiplying by 4, which we do by * ANDing with ~3. */ s_roundup = new_stmt(cstate, BPF_LD|BPF_MEM); s_roundup->s.k = cstate->off_linkpl.reg; sappend(s, s_roundup); s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_IMM); s2->s.k = 3; sappend(s, s2); s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_IMM); s2->s.k = (bpf_u_int32)~3; sappend(s, s2); s2 = new_stmt(cstate, BPF_ST); s2->s.k = cstate->off_linkpl.reg; sappend(s, s2); sjset_tsft_datapad->s.jt = s_roundup; sjset_tsft_datapad->s.jf = snext; sjset_notsft_datapad->s.jt = s_roundup; sjset_notsft_datapad->s.jf = snext; } else sjset_qos->s.jf = snext; return s; } static void insert_compute_vloffsets(compiler_state_t *cstate, struct block *b) { struct slist *s; /* There is an implicit dependency between the link * payload and link header since the payload computation * includes the variable part of the header. Therefore, * if nobody else has allocated a register for the link * header and we need it, do it now. */ if (cstate->off_linkpl.reg != -1 && cstate->off_linkhdr.is_variable && cstate->off_linkhdr.reg == -1) cstate->off_linkhdr.reg = alloc_reg(cstate); /* * For link-layer types that have a variable-length header * preceding the link-layer header, generate code to load * the offset of the link-layer header into the register * assigned to that offset, if any. * * XXX - this, and the next switch statement, won't handle * encapsulation of 802.11 or 802.11+radio information in * some other protocol stack. That's significantly more * complicated. */ switch (cstate->outermostlinktype) { case DLT_PRISM_HEADER: s = gen_load_prism_llprefixlen(cstate); break; case DLT_IEEE802_11_RADIO_AVS: s = gen_load_avs_llprefixlen(cstate); break; case DLT_IEEE802_11_RADIO: s = gen_load_radiotap_llprefixlen(cstate); break; case DLT_PPI: s = gen_load_ppi_llprefixlen(cstate); break; default: s = NULL; break; } /* * For link-layer types that have a variable-length link-layer * header, generate code to load the offset of the link-layer * payload into the register assigned to that offset, if any. */ switch (cstate->outermostlinktype) { case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO_AVS: case DLT_IEEE802_11_RADIO: case DLT_PPI: s = gen_load_802_11_header_len(cstate, s, b->stmts); break; case DLT_PFLOG: s = gen_load_pflog_llprefixlen(cstate); break; } /* * If there is no initialization yet and we need variable * length offsets for VLAN, initialize them to zero */ if (s == NULL && cstate->is_vlan_vloffset) { struct slist *s2; if (cstate->off_linkpl.reg == -1) cstate->off_linkpl.reg = alloc_reg(cstate); if (cstate->off_linktype.reg == -1) cstate->off_linktype.reg = alloc_reg(cstate); s = new_stmt(cstate, BPF_LD|BPF_W|BPF_IMM); s->s.k = 0; s2 = new_stmt(cstate, BPF_ST); s2->s.k = cstate->off_linkpl.reg; sappend(s, s2); s2 = new_stmt(cstate, BPF_ST); s2->s.k = cstate->off_linktype.reg; sappend(s, s2); } /* * If we have any offset-loading code, append all the * existing statements in the block to those statements, * and make the resulting list the list of statements * for the block. */ if (s != NULL) { sappend(s, b->stmts); b->stmts = s; } } static struct block * gen_ppi_dlt_check(compiler_state_t *cstate) { struct slist *s_load_dlt; struct block *b; if (cstate->linktype == DLT_PPI) { /* Create the statements that check for the DLT */ s_load_dlt = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS); s_load_dlt->s.k = 4; b = new_block(cstate, JMP(BPF_JEQ)); b->stmts = s_load_dlt; b->s.k = SWAPLONG(DLT_IEEE802_11); } else { b = NULL; } return b; } /* * Take an absolute offset, and: * * if it has no variable part, return NULL; * * if it has a variable part, generate code to load the register * containing that variable part into the X register, returning * a pointer to that code - if no register for that offset has * been allocated, allocate it first. * * (The code to set that register will be generated later, but will * be placed earlier in the code sequence.) */ static struct slist * gen_abs_offset_varpart(compiler_state_t *cstate, bpf_abs_offset *off) { struct slist *s; if (off->is_variable) { if (off->reg == -1) { /* * We haven't yet assigned a register for the * variable part of the offset of the link-layer * header; allocate one. */ off->reg = alloc_reg(cstate); } /* * Load the register containing the variable part of the * offset of the link-layer header into the X register. */ s = new_stmt(cstate, BPF_LDX|BPF_MEM); s->s.k = off->reg; return s; } else { /* * That offset isn't variable, there's no variable part, * so we don't need to generate any code. */ return NULL; } } /* * Map an Ethernet type to the equivalent PPP type. */ static bpf_u_int32 ethertype_to_ppptype(bpf_u_int32 ll_proto) { switch (ll_proto) { case ETHERTYPE_IP: ll_proto = PPP_IP; break; case ETHERTYPE_IPV6: ll_proto = PPP_IPV6; break; case ETHERTYPE_DN: ll_proto = PPP_DECNET; break; case ETHERTYPE_ATALK: ll_proto = PPP_APPLE; break; case ETHERTYPE_NS: ll_proto = PPP_NS; break; case LLCSAP_ISONS: ll_proto = PPP_OSI; break; case LLCSAP_8021D: /* * I'm assuming the "Bridging PDU"s that go * over PPP are Spanning Tree Protocol * Bridging PDUs. */ ll_proto = PPP_BRPDU; break; case LLCSAP_IPX: ll_proto = PPP_IPX; break; } return (ll_proto); } /* * Generate any tests that, for encapsulation of a link-layer packet * inside another protocol stack, need to be done to check for those * link-layer packets (and that haven't already been done by a check * for that encapsulation). */ static struct block * gen_prevlinkhdr_check(compiler_state_t *cstate) { struct block *b0; if (cstate->is_geneve) return gen_geneve_ll_check(cstate); switch (cstate->prevlinktype) { case DLT_SUNATM: /* * This is LANE-encapsulated Ethernet; check that the LANE * packet doesn't begin with an LE Control marker, i.e. * that it's data, not a control message. * * (We've already generated a test for LANE.) */ b0 = gen_cmp(cstate, OR_PREVLINKHDR, SUNATM_PKT_BEGIN_POS, BPF_H, 0xFF00); gen_not(b0); return b0; default: /* * No such tests are necessary. */ return NULL; } /*NOTREACHED*/ } /* * The three different values we should check for when checking for an * IPv6 packet with DLT_NULL. */ #define BSD_AFNUM_INET6_BSD 24 /* NetBSD, OpenBSD, BSD/OS, Npcap */ #define BSD_AFNUM_INET6_FREEBSD 28 /* FreeBSD */ #define BSD_AFNUM_INET6_DARWIN 30 /* macOS, iOS, other Darwin-based OSes */ /* * Generate code to match a particular packet type by matching the * link-layer type field or fields in the 802.2 LLC header. * * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP * value, if <= ETHERMTU. */ static struct block * gen_linktype(compiler_state_t *cstate, bpf_u_int32 ll_proto) { struct block *b0, *b1, *b2; const char *description; /* are we checking MPLS-encapsulated packets? */ if (cstate->label_stack_depth > 0) return gen_mpls_linktype(cstate, ll_proto); switch (cstate->linktype) { case DLT_EN10MB: case DLT_NETANALYZER: case DLT_NETANALYZER_TRANSPARENT: /* Geneve has an EtherType regardless of whether there is an * L2 header. */ if (!cstate->is_geneve) b0 = gen_prevlinkhdr_check(cstate); else b0 = NULL; b1 = gen_ether_linktype(cstate, ll_proto); if (b0 != NULL) gen_and(b0, b1); return b1; /*NOTREACHED*/ case DLT_C_HDLC: case DLT_HDLC: switch (ll_proto) { case LLCSAP_ISONS: ll_proto = (ll_proto << 8 | LLCSAP_ISONS); /* fall through */ default: return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, ll_proto); /*NOTREACHED*/ } case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO_AVS: case DLT_IEEE802_11_RADIO: case DLT_PPI: /* * Check that we have a data frame. */ b0 = gen_check_802_11_data_frame(cstate); /* * Now check for the specified link-layer type. */ b1 = gen_llc_linktype(cstate, ll_proto); gen_and(b0, b1); return b1; /*NOTREACHED*/ case DLT_FDDI: /* * XXX - check for LLC frames. */ return gen_llc_linktype(cstate, ll_proto); /*NOTREACHED*/ case DLT_IEEE802: /* * XXX - check for LLC PDUs, as per IEEE 802.5. */ return gen_llc_linktype(cstate, ll_proto); /*NOTREACHED*/ case DLT_ATM_RFC1483: case DLT_ATM_CLIP: case DLT_IP_OVER_FC: return gen_llc_linktype(cstate, ll_proto); /*NOTREACHED*/ case DLT_SUNATM: /* * Check for an LLC-encapsulated version of this protocol; * if we were checking for LANE, linktype would no longer * be DLT_SUNATM. * * Check for LLC encapsulation and then check the protocol. */ b0 = gen_atmfield_code_internal(cstate, A_PROTOTYPE, PT_LLC, BPF_JEQ, 0); b1 = gen_llc_linktype(cstate, ll_proto); gen_and(b0, b1); return b1; /*NOTREACHED*/ case DLT_LINUX_SLL: return gen_linux_sll_linktype(cstate, ll_proto); /*NOTREACHED*/ case DLT_SLIP: case DLT_SLIP_BSDOS: case DLT_RAW: /* * These types don't provide any type field; packets * are always IPv4 or IPv6. * * XXX - for IPv4, check for a version number of 4, and, * for IPv6, check for a version number of 6? */ switch (ll_proto) { case ETHERTYPE_IP: /* Check for a version number of 4. */ return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, 0x40, 0xF0); case ETHERTYPE_IPV6: /* Check for a version number of 6. */ return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, 0x60, 0xF0); default: return gen_false(cstate); /* always false */ } /*NOTREACHED*/ case DLT_IPV4: /* * Raw IPv4, so no type field. */ if (ll_proto == ETHERTYPE_IP) return gen_true(cstate); /* always true */ /* Checking for something other than IPv4; always false */ return gen_false(cstate); /*NOTREACHED*/ case DLT_IPV6: /* * Raw IPv6, so no type field. */ if (ll_proto == ETHERTYPE_IPV6) return gen_true(cstate); /* always true */ /* Checking for something other than IPv6; always false */ return gen_false(cstate); /*NOTREACHED*/ case DLT_PPP: case DLT_PPP_PPPD: case DLT_PPP_SERIAL: case DLT_PPP_ETHER: /* * We use Ethernet protocol types inside libpcap; * map them to the corresponding PPP protocol types. */ return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, ethertype_to_ppptype(ll_proto)); /*NOTREACHED*/ case DLT_PPP_BSDOS: /* * We use Ethernet protocol types inside libpcap; * map them to the corresponding PPP protocol types. */ switch (ll_proto) { case ETHERTYPE_IP: /* * Also check for Van Jacobson-compressed IP. * XXX - do this for other forms of PPP? */ b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, PPP_IP); b1 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, PPP_VJC); gen_or(b0, b1); b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, PPP_VJNC); gen_or(b1, b0); return b0; default: return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, ethertype_to_ppptype(ll_proto)); } /*NOTREACHED*/ case DLT_NULL: case DLT_LOOP: case DLT_ENC: switch (ll_proto) { case ETHERTYPE_IP: return (gen_loopback_linktype(cstate, AF_INET)); case ETHERTYPE_IPV6: /* * AF_ values may, unfortunately, be platform- * dependent; AF_INET isn't, because everybody * used 4.2BSD's value, but AF_INET6 is, because * 4.2BSD didn't have a value for it (given that * IPv6 didn't exist back in the early 1980's), * and they all picked their own values. * * This means that, if we're reading from a * savefile, we need to check for all the * possible values. * * If we're doing a live capture, we only need * to check for this platform's value; however, * Npcap uses 24, which isn't Windows's AF_INET6 * value. (Given the multiple different values, * programs that read pcap files shouldn't be * checking for their platform's AF_INET6 value * anyway, they should check for all of the * possible values. and they might as well do * that even for live captures.) */ if (cstate->bpf_pcap->rfile != NULL) { /* * Savefile - check for all three * possible IPv6 values. */ b0 = gen_loopback_linktype(cstate, BSD_AFNUM_INET6_BSD); b1 = gen_loopback_linktype(cstate, BSD_AFNUM_INET6_FREEBSD); gen_or(b0, b1); b0 = gen_loopback_linktype(cstate, BSD_AFNUM_INET6_DARWIN); gen_or(b0, b1); return (b1); } else { /* * Live capture, so we only need to * check for the value used on this * platform. */ #ifdef _WIN32 /* * Npcap doesn't use Windows's AF_INET6, * as that collides with AF_IPX on * some BSDs (both have the value 23). * Instead, it uses 24. */ return (gen_loopback_linktype(cstate, 24)); #else /* _WIN32 */ #ifdef AF_INET6 return (gen_loopback_linktype(cstate, AF_INET6)); #else /* AF_INET6 */ /* * I guess this platform doesn't support * IPv6, so we just reject all packets. */ return gen_false(cstate); #endif /* AF_INET6 */ #endif /* _WIN32 */ } default: /* * Not a type on which we support filtering. * XXX - support those that have AF_ values * #defined on this platform, at least? */ return gen_false(cstate); } case DLT_PFLOG: /* * af field is host byte order in contrast to the rest of * the packet. */ if (ll_proto == ETHERTYPE_IP) return (gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, af), BPF_B, AF_INET)); else if (ll_proto == ETHERTYPE_IPV6) return (gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, af), BPF_B, AF_INET6)); else return gen_false(cstate); /*NOTREACHED*/ case DLT_ARCNET: case DLT_ARCNET_LINUX: /* * XXX should we check for first fragment if the protocol * uses PHDS? */ switch (ll_proto) { default: return gen_false(cstate); case ETHERTYPE_IPV6: return (gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B, ARCTYPE_INET6)); case ETHERTYPE_IP: b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B, ARCTYPE_IP); b1 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B, ARCTYPE_IP_OLD); gen_or(b0, b1); return (b1); case ETHERTYPE_ARP: b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B, ARCTYPE_ARP); b1 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B, ARCTYPE_ARP_OLD); gen_or(b0, b1); return (b1); case ETHERTYPE_REVARP: return (gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B, ARCTYPE_REVARP)); case ETHERTYPE_ATALK: return (gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B, ARCTYPE_ATALK)); } /*NOTREACHED*/ case DLT_LTALK: switch (ll_proto) { case ETHERTYPE_ATALK: return gen_true(cstate); default: return gen_false(cstate); } /*NOTREACHED*/ case DLT_FRELAY: /* * XXX - assumes a 2-byte Frame Relay header with * DLCI and flags. What if the address is longer? */ switch (ll_proto) { case ETHERTYPE_IP: /* * Check for the special NLPID for IP. */ return gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | 0xcc); case ETHERTYPE_IPV6: /* * Check for the special NLPID for IPv6. */ return gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | 0x8e); case LLCSAP_ISONS: /* * Check for several OSI protocols. * * Frame Relay packets typically have an OSI * NLPID at the beginning; we check for each * of them. * * What we check for is the NLPID and a frame * control field of UI, i.e. 0x03 followed * by the NLPID. */ b0 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | ISO8473_CLNP); b1 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | ISO9542_ESIS); b2 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | ISO10589_ISIS); gen_or(b1, b2); gen_or(b0, b2); return b2; default: return gen_false(cstate); } /*NOTREACHED*/ case DLT_MFR: bpf_error(cstate, "Multi-link Frame Relay link-layer type filtering not implemented"); case DLT_JUNIPER_MFR: case DLT_JUNIPER_MLFR: case DLT_JUNIPER_MLPPP: case DLT_JUNIPER_ATM1: case DLT_JUNIPER_ATM2: case DLT_JUNIPER_PPPOE: case DLT_JUNIPER_PPPOE_ATM: case DLT_JUNIPER_GGSN: case DLT_JUNIPER_ES: case DLT_JUNIPER_MONITOR: case DLT_JUNIPER_SERVICES: case DLT_JUNIPER_ETHER: case DLT_JUNIPER_PPP: case DLT_JUNIPER_FRELAY: case DLT_JUNIPER_CHDLC: case DLT_JUNIPER_VP: case DLT_JUNIPER_ST: case DLT_JUNIPER_ISM: case DLT_JUNIPER_VS: case DLT_JUNIPER_SRX_E2E: case DLT_JUNIPER_FIBRECHANNEL: case DLT_JUNIPER_ATM_CEMIC: /* just lets verify the magic number for now - * on ATM we may have up to 6 different encapsulations on the wire * and need a lot of heuristics to figure out that the payload * might be; * * FIXME encapsulation specific BPF_ filters */ return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_W, 0x4d474300, 0xffffff00); /* compare the magic number */ case DLT_BACNET_MS_TP: return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_W, 0x55FF0000, 0xffff0000); case DLT_IPNET: return gen_ipnet_linktype(cstate, ll_proto); case DLT_LINUX_IRDA: bpf_error(cstate, "IrDA link-layer type filtering not implemented"); case DLT_DOCSIS: bpf_error(cstate, "DOCSIS link-layer type filtering not implemented"); case DLT_MTP2: case DLT_MTP2_WITH_PHDR: bpf_error(cstate, "MTP2 link-layer type filtering not implemented"); case DLT_ERF: bpf_error(cstate, "ERF link-layer type filtering not implemented"); case DLT_PFSYNC: bpf_error(cstate, "PFSYNC link-layer type filtering not implemented"); case DLT_LINUX_LAPD: bpf_error(cstate, "LAPD link-layer type filtering not implemented"); case DLT_USB_FREEBSD: case DLT_USB_LINUX: case DLT_USB_LINUX_MMAPPED: case DLT_USBPCAP: bpf_error(cstate, "USB link-layer type filtering not implemented"); case DLT_BLUETOOTH_HCI_H4: case DLT_BLUETOOTH_HCI_H4_WITH_PHDR: bpf_error(cstate, "Bluetooth link-layer type filtering not implemented"); case DLT_CAN20B: case DLT_CAN_SOCKETCAN: bpf_error(cstate, "CAN link-layer type filtering not implemented"); case DLT_IEEE802_15_4: case DLT_IEEE802_15_4_LINUX: case DLT_IEEE802_15_4_NONASK_PHY: case DLT_IEEE802_15_4_NOFCS: case DLT_IEEE802_15_4_TAP: bpf_error(cstate, "IEEE 802.15.4 link-layer type filtering not implemented"); case DLT_IEEE802_16_MAC_CPS_RADIO: bpf_error(cstate, "IEEE 802.16 link-layer type filtering not implemented"); case DLT_SITA: bpf_error(cstate, "SITA link-layer type filtering not implemented"); case DLT_RAIF1: bpf_error(cstate, "RAIF1 link-layer type filtering not implemented"); case DLT_IPMB_KONTRON: case DLT_IPMB_LINUX: bpf_error(cstate, "IPMB link-layer type filtering not implemented"); case DLT_AX25_KISS: bpf_error(cstate, "AX.25 link-layer type filtering not implemented"); case DLT_NFLOG: /* Using the fixed-size NFLOG header it is possible to tell only * the address family of the packet, other meaningful data is * either missing or behind TLVs. */ bpf_error(cstate, "NFLOG link-layer type filtering not implemented"); default: /* * Does this link-layer header type have a field * indicating the type of the next protocol? If * so, off_linktype.constant_part will be the offset of that * field in the packet; if not, it will be OFFSET_NOT_SET. */ if (cstate->off_linktype.constant_part != OFFSET_NOT_SET) { /* * Yes; assume it's an Ethernet type. (If * it's not, it needs to be handled specially * above.) */ return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, ll_proto); /*NOTREACHED */ } else { /* * No; report an error. */ description = pcap_datalink_val_to_description_or_dlt(cstate->linktype); bpf_error(cstate, "%s link-layer type filtering not implemented", description); /*NOTREACHED */ } } } /* * Check for an LLC SNAP packet with a given organization code and * protocol type; we check the entire contents of the 802.2 LLC and * snap headers, checking for DSAP and SSAP of SNAP and a control * field of 0x03 in the LLC header, and for the specified organization * code and protocol type in the SNAP header. */ static struct block * gen_snap(compiler_state_t *cstate, bpf_u_int32 orgcode, bpf_u_int32 ptype) { u_char snapblock[8]; snapblock[0] = LLCSAP_SNAP; /* DSAP = SNAP */ snapblock[1] = LLCSAP_SNAP; /* SSAP = SNAP */ snapblock[2] = 0x03; /* control = UI */ snapblock[3] = (u_char)(orgcode >> 16); /* upper 8 bits of organization code */ snapblock[4] = (u_char)(orgcode >> 8); /* middle 8 bits of organization code */ snapblock[5] = (u_char)(orgcode >> 0); /* lower 8 bits of organization code */ snapblock[6] = (u_char)(ptype >> 8); /* upper 8 bits of protocol type */ snapblock[7] = (u_char)(ptype >> 0); /* lower 8 bits of protocol type */ return gen_bcmp(cstate, OR_LLC, 0, 8, snapblock); } /* * Generate code to match frames with an LLC header. */ static struct block * gen_llc_internal(compiler_state_t *cstate) { struct block *b0, *b1; switch (cstate->linktype) { case DLT_EN10MB: /* * We check for an Ethernet type field less than * 1500, which means it's an 802.3 length field. */ b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU); gen_not(b0); /* * Now check for the purported DSAP and SSAP not being * 0xFF, to rule out NetWare-over-802.3. */ b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, 0xFFFF); gen_not(b1); gen_and(b0, b1); return b1; case DLT_SUNATM: /* * We check for LLC traffic. */ b0 = gen_atmtype_llc(cstate); return b0; case DLT_IEEE802: /* Token Ring */ /* * XXX - check for LLC frames. */ return gen_true(cstate); case DLT_FDDI: /* * XXX - check for LLC frames. */ return gen_true(cstate); case DLT_ATM_RFC1483: /* * For LLC encapsulation, these are defined to have an * 802.2 LLC header. * * For VC encapsulation, they don't, but there's no * way to check for that; the protocol used on the VC * is negotiated out of band. */ return gen_true(cstate); case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO: case DLT_IEEE802_11_RADIO_AVS: case DLT_PPI: /* * Check that we have a data frame. */ b0 = gen_check_802_11_data_frame(cstate); return b0; default: bpf_error(cstate, "'llc' not supported for %s", pcap_datalink_val_to_description_or_dlt(cstate->linktype)); /*NOTREACHED*/ } } struct block * gen_llc(compiler_state_t *cstate) { /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); return gen_llc_internal(cstate); } struct block * gen_llc_i(compiler_state_t *cstate) { struct block *b0, *b1; struct slist *s; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); /* * Check whether this is an LLC frame. */ b0 = gen_llc_internal(cstate); /* * Load the control byte and test the low-order bit; it must * be clear for I frames. */ s = gen_load_a(cstate, OR_LLC, 2, BPF_B); b1 = new_block(cstate, JMP(BPF_JSET)); b1->s.k = 0x01; b1->stmts = s; gen_not(b1); gen_and(b0, b1); return b1; } struct block * gen_llc_s(compiler_state_t *cstate) { struct block *b0, *b1; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); /* * Check whether this is an LLC frame. */ b0 = gen_llc_internal(cstate); /* * Now compare the low-order 2 bit of the control byte against * the appropriate value for S frames. */ b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, LLC_S_FMT, 0x03); gen_and(b0, b1); return b1; } struct block * gen_llc_u(compiler_state_t *cstate) { struct block *b0, *b1; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); /* * Check whether this is an LLC frame. */ b0 = gen_llc_internal(cstate); /* * Now compare the low-order 2 bit of the control byte against * the appropriate value for U frames. */ b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, LLC_U_FMT, 0x03); gen_and(b0, b1); return b1; } struct block * gen_llc_s_subtype(compiler_state_t *cstate, bpf_u_int32 subtype) { struct block *b0, *b1; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); /* * Check whether this is an LLC frame. */ b0 = gen_llc_internal(cstate); /* * Now check for an S frame with the appropriate type. */ b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, subtype, LLC_S_CMD_MASK); gen_and(b0, b1); return b1; } struct block * gen_llc_u_subtype(compiler_state_t *cstate, bpf_u_int32 subtype) { struct block *b0, *b1; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); /* * Check whether this is an LLC frame. */ b0 = gen_llc_internal(cstate); /* * Now check for a U frame with the appropriate type. */ b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, subtype, LLC_U_CMD_MASK); gen_and(b0, b1); return b1; } /* * Generate code to match a particular packet type, for link-layer types * using 802.2 LLC headers. * * This is *NOT* used for Ethernet; "gen_ether_linktype()" is used * for that - it handles the D/I/X Ethernet vs. 802.3+802.2 issues. * * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP * value, if <= ETHERMTU. We use that to determine whether to * match the DSAP or both DSAP and LSAP or to check the OUI and * protocol ID in a SNAP header. */ static struct block * gen_llc_linktype(compiler_state_t *cstate, bpf_u_int32 ll_proto) { /* * XXX - handle token-ring variable-length header. */ switch (ll_proto) { case LLCSAP_IP: case LLCSAP_ISONS: case LLCSAP_NETBEUI: /* * XXX - should we check both the DSAP and the * SSAP, like this, or should we check just the * DSAP, as we do for other SAP values? */ return gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_u_int32) ((ll_proto << 8) | ll_proto)); case LLCSAP_IPX: /* * XXX - are there ever SNAP frames for IPX on * non-Ethernet 802.x networks? */ return gen_cmp(cstate, OR_LLC, 0, BPF_B, LLCSAP_IPX); case ETHERTYPE_ATALK: /* * 802.2-encapsulated ETHERTYPE_ATALK packets are * SNAP packets with an organization code of * 0x080007 (Apple, for Appletalk) and a protocol * type of ETHERTYPE_ATALK (Appletalk). * * XXX - check for an organization code of * encapsulated Ethernet as well? */ return gen_snap(cstate, 0x080007, ETHERTYPE_ATALK); default: /* * XXX - we don't have to check for IPX 802.3 * here, but should we check for the IPX Ethertype? */ if (ll_proto <= ETHERMTU) { /* * This is an LLC SAP value, so check * the DSAP. */ return gen_cmp(cstate, OR_LLC, 0, BPF_B, ll_proto); } else { /* * This is an Ethernet type; we assume that it's * unlikely that it'll appear in the right place * at random, and therefore check only the * location that would hold the Ethernet type * in a SNAP frame with an organization code of * 0x000000 (encapsulated Ethernet). * * XXX - if we were to check for the SNAP DSAP and * LSAP, as per XXX, and were also to check for an * organization code of 0x000000 (encapsulated * Ethernet), we'd do * * return gen_snap(cstate, 0x000000, ll_proto); * * here; for now, we don't, as per the above. * I don't know whether it's worth the extra CPU * time to do the right check or not. */ return gen_cmp(cstate, OR_LLC, 6, BPF_H, ll_proto); } } } static struct block * gen_hostop(compiler_state_t *cstate, bpf_u_int32 addr, bpf_u_int32 mask, int dir, bpf_u_int32 ll_proto, u_int src_off, u_int dst_off) { struct block *b0, *b1; u_int offset; switch (dir) { case Q_SRC: offset = src_off; break; case Q_DST: offset = dst_off; break; case Q_AND: b0 = gen_hostop(cstate, addr, mask, Q_SRC, ll_proto, src_off, dst_off); b1 = gen_hostop(cstate, addr, mask, Q_DST, ll_proto, src_off, dst_off); gen_and(b0, b1); return b1; case Q_DEFAULT: case Q_OR: b0 = gen_hostop(cstate, addr, mask, Q_SRC, ll_proto, src_off, dst_off); b1 = gen_hostop(cstate, addr, mask, Q_DST, ll_proto, src_off, dst_off); gen_or(b0, b1); return b1; case Q_ADDR1: bpf_error(cstate, "'addr1' and 'address1' are not valid qualifiers for addresses other than 802.11 MAC addresses"); /*NOTREACHED*/ case Q_ADDR2: bpf_error(cstate, "'addr2' and 'address2' are not valid qualifiers for addresses other than 802.11 MAC addresses"); /*NOTREACHED*/ case Q_ADDR3: bpf_error(cstate, "'addr3' and 'address3' are not valid qualifiers for addresses other than 802.11 MAC addresses"); /*NOTREACHED*/ case Q_ADDR4: bpf_error(cstate, "'addr4' and 'address4' are not valid qualifiers for addresses other than 802.11 MAC addresses"); /*NOTREACHED*/ case Q_RA: bpf_error(cstate, "'ra' is not a valid qualifier for addresses other than 802.11 MAC addresses"); /*NOTREACHED*/ case Q_TA: bpf_error(cstate, "'ta' is not a valid qualifier for addresses other than 802.11 MAC addresses"); /*NOTREACHED*/ default: abort(); /*NOTREACHED*/ } b0 = gen_linktype(cstate, ll_proto); b1 = gen_mcmp(cstate, OR_LINKPL, offset, BPF_W, addr, mask); gen_and(b0, b1); return b1; } #ifdef INET6 static struct block * gen_hostop6(compiler_state_t *cstate, struct in6_addr *addr, struct in6_addr *mask, int dir, bpf_u_int32 ll_proto, u_int src_off, u_int dst_off) { struct block *b0, *b1; u_int offset; uint32_t *a, *m; switch (dir) { case Q_SRC: offset = src_off; break; case Q_DST: offset = dst_off; break; case Q_AND: b0 = gen_hostop6(cstate, addr, mask, Q_SRC, ll_proto, src_off, dst_off); b1 = gen_hostop6(cstate, addr, mask, Q_DST, ll_proto, src_off, dst_off); gen_and(b0, b1); return b1; case Q_DEFAULT: case Q_OR: b0 = gen_hostop6(cstate, addr, mask, Q_SRC, ll_proto, src_off, dst_off); b1 = gen_hostop6(cstate, addr, mask, Q_DST, ll_proto, src_off, dst_off); gen_or(b0, b1); return b1; case Q_ADDR1: bpf_error(cstate, "'addr1' and 'address1' are not valid qualifiers for addresses other than 802.11 MAC addresses"); /*NOTREACHED*/ case Q_ADDR2: bpf_error(cstate, "'addr2' and 'address2' are not valid qualifiers for addresses other than 802.11 MAC addresses"); /*NOTREACHED*/ case Q_ADDR3: bpf_error(cstate, "'addr3' and 'address3' are not valid qualifiers for addresses other than 802.11 MAC addresses"); /*NOTREACHED*/ case Q_ADDR4: bpf_error(cstate, "'addr4' and 'address4' are not valid qualifiers for addresses other than 802.11 MAC addresses"); /*NOTREACHED*/ case Q_RA: bpf_error(cstate, "'ra' is not a valid qualifier for addresses other than 802.11 MAC addresses"); /*NOTREACHED*/ case Q_TA: bpf_error(cstate, "'ta' is not a valid qualifier for addresses other than 802.11 MAC addresses"); /*NOTREACHED*/ default: abort(); /*NOTREACHED*/ } /* this order is important */ a = (uint32_t *)addr; m = (uint32_t *)mask; b1 = gen_mcmp(cstate, OR_LINKPL, offset + 12, BPF_W, ntohl(a[3]), ntohl(m[3])); b0 = gen_mcmp(cstate, OR_LINKPL, offset + 8, BPF_W, ntohl(a[2]), ntohl(m[2])); gen_and(b0, b1); b0 = gen_mcmp(cstate, OR_LINKPL, offset + 4, BPF_W, ntohl(a[1]), ntohl(m[1])); gen_and(b0, b1); b0 = gen_mcmp(cstate, OR_LINKPL, offset + 0, BPF_W, ntohl(a[0]), ntohl(m[0])); gen_and(b0, b1); b0 = gen_linktype(cstate, ll_proto); gen_and(b0, b1); return b1; } #endif static struct block * gen_ehostop(compiler_state_t *cstate, const u_char *eaddr, int dir) { register struct block *b0, *b1; switch (dir) { case Q_SRC: return gen_bcmp(cstate, OR_LINKHDR, 6, 6, eaddr); case Q_DST: return gen_bcmp(cstate, OR_LINKHDR, 0, 6, eaddr); case Q_AND: b0 = gen_ehostop(cstate, eaddr, Q_SRC); b1 = gen_ehostop(cstate, eaddr, Q_DST); gen_and(b0, b1); return b1; case Q_DEFAULT: case Q_OR: b0 = gen_ehostop(cstate, eaddr, Q_SRC); b1 = gen_ehostop(cstate, eaddr, Q_DST); gen_or(b0, b1); return b1; case Q_ADDR1: bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11 with 802.11 headers"); /*NOTREACHED*/ case Q_ADDR2: bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11 with 802.11 headers"); /*NOTREACHED*/ case Q_ADDR3: bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11 with 802.11 headers"); /*NOTREACHED*/ case Q_ADDR4: bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11 with 802.11 headers"); /*NOTREACHED*/ case Q_RA: bpf_error(cstate, "'ra' is only supported on 802.11 with 802.11 headers"); /*NOTREACHED*/ case Q_TA: bpf_error(cstate, "'ta' is only supported on 802.11 with 802.11 headers"); /*NOTREACHED*/ } abort(); /*NOTREACHED*/ } /* * Like gen_ehostop, but for DLT_FDDI */ static struct block * gen_fhostop(compiler_state_t *cstate, const u_char *eaddr, int dir) { struct block *b0, *b1; switch (dir) { case Q_SRC: return gen_bcmp(cstate, OR_LINKHDR, 6 + 1 + cstate->pcap_fddipad, 6, eaddr); case Q_DST: return gen_bcmp(cstate, OR_LINKHDR, 0 + 1 + cstate->pcap_fddipad, 6, eaddr); case Q_AND: b0 = gen_fhostop(cstate, eaddr, Q_SRC); b1 = gen_fhostop(cstate, eaddr, Q_DST); gen_and(b0, b1); return b1; case Q_DEFAULT: case Q_OR: b0 = gen_fhostop(cstate, eaddr, Q_SRC); b1 = gen_fhostop(cstate, eaddr, Q_DST); gen_or(b0, b1); return b1; case Q_ADDR1: bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11"); /*NOTREACHED*/ case Q_ADDR2: bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11"); /*NOTREACHED*/ case Q_ADDR3: bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11"); /*NOTREACHED*/ case Q_ADDR4: bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11"); /*NOTREACHED*/ case Q_RA: bpf_error(cstate, "'ra' is only supported on 802.11"); /*NOTREACHED*/ case Q_TA: bpf_error(cstate, "'ta' is only supported on 802.11"); /*NOTREACHED*/ } abort(); /*NOTREACHED*/ } /* * Like gen_ehostop, but for DLT_IEEE802 (Token Ring) */ static struct block * gen_thostop(compiler_state_t *cstate, const u_char *eaddr, int dir) { register struct block *b0, *b1; switch (dir) { case Q_SRC: return gen_bcmp(cstate, OR_LINKHDR, 8, 6, eaddr); case Q_DST: return gen_bcmp(cstate, OR_LINKHDR, 2, 6, eaddr); case Q_AND: b0 = gen_thostop(cstate, eaddr, Q_SRC); b1 = gen_thostop(cstate, eaddr, Q_DST); gen_and(b0, b1); return b1; case Q_DEFAULT: case Q_OR: b0 = gen_thostop(cstate, eaddr, Q_SRC); b1 = gen_thostop(cstate, eaddr, Q_DST); gen_or(b0, b1); return b1; case Q_ADDR1: bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11"); /*NOTREACHED*/ case Q_ADDR2: bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11"); /*NOTREACHED*/ case Q_ADDR3: bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11"); /*NOTREACHED*/ case Q_ADDR4: bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11"); /*NOTREACHED*/ case Q_RA: bpf_error(cstate, "'ra' is only supported on 802.11"); /*NOTREACHED*/ case Q_TA: bpf_error(cstate, "'ta' is only supported on 802.11"); /*NOTREACHED*/ } abort(); /*NOTREACHED*/ } /* * Like gen_ehostop, but for DLT_IEEE802_11 (802.11 wireless LAN) and * various 802.11 + radio headers. */ static struct block * gen_wlanhostop(compiler_state_t *cstate, const u_char *eaddr, int dir) { register struct block *b0, *b1, *b2; register struct slist *s; #ifdef ENABLE_WLAN_FILTERING_PATCH /* * TODO GV 20070613 * We need to disable the optimizer because the optimizer is buggy * and wipes out some LD instructions generated by the below * code to validate the Frame Control bits */ cstate->no_optimize = 1; #endif /* ENABLE_WLAN_FILTERING_PATCH */ switch (dir) { case Q_SRC: /* * Oh, yuk. * * For control frames, there is no SA. * * For management frames, SA is at an * offset of 10 from the beginning of * the packet. * * For data frames, SA is at an offset * of 10 from the beginning of the packet * if From DS is clear, at an offset of * 16 from the beginning of the packet * if From DS is set and To DS is clear, * and an offset of 24 from the beginning * of the packet if From DS is set and To DS * is set. */ /* * Generate the tests to be done for data frames * with From DS set. * * First, check for To DS set, i.e. check "link[1] & 0x01". */ s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B); b1 = new_block(cstate, JMP(BPF_JSET)); b1->s.k = 0x01; /* To DS */ b1->stmts = s; /* * If To DS is set, the SA is at 24. */ b0 = gen_bcmp(cstate, OR_LINKHDR, 24, 6, eaddr); gen_and(b1, b0); /* * Now, check for To DS not set, i.e. check * "!(link[1] & 0x01)". */ s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B); b2 = new_block(cstate, JMP(BPF_JSET)); b2->s.k = 0x01; /* To DS */ b2->stmts = s; gen_not(b2); /* * If To DS is not set, the SA is at 16. */ b1 = gen_bcmp(cstate, OR_LINKHDR, 16, 6, eaddr); gen_and(b2, b1); /* * Now OR together the last two checks. That gives * the complete set of checks for data frames with * From DS set. */ gen_or(b1, b0); /* * Now check for From DS being set, and AND that with * the ORed-together checks. */ s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B); b1 = new_block(cstate, JMP(BPF_JSET)); b1->s.k = 0x02; /* From DS */ b1->stmts = s; gen_and(b1, b0); /* * Now check for data frames with From DS not set. */ s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B); b2 = new_block(cstate, JMP(BPF_JSET)); b2->s.k = 0x02; /* From DS */ b2->stmts = s; gen_not(b2); /* * If From DS isn't set, the SA is at 10. */ b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr); gen_and(b2, b1); /* * Now OR together the checks for data frames with * From DS not set and for data frames with From DS * set; that gives the checks done for data frames. */ gen_or(b1, b0); /* * Now check for a data frame. * I.e, check "link[0] & 0x08". */ s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B); b1 = new_block(cstate, JMP(BPF_JSET)); b1->s.k = 0x08; b1->stmts = s; /* * AND that with the checks done for data frames. */ gen_and(b1, b0); /* * If the high-order bit of the type value is 0, this * is a management frame. * I.e, check "!(link[0] & 0x08)". */ s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B); b2 = new_block(cstate, JMP(BPF_JSET)); b2->s.k = 0x08; b2->stmts = s; gen_not(b2); /* * For management frames, the SA is at 10. */ b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr); gen_and(b2, b1); /* * OR that with the checks done for data frames. * That gives the checks done for management and * data frames. */ gen_or(b1, b0); /* * If the low-order bit of the type value is 1, * this is either a control frame or a frame * with a reserved type, and thus not a * frame with an SA. * * I.e., check "!(link[0] & 0x04)". */ s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B); b1 = new_block(cstate, JMP(BPF_JSET)); b1->s.k = 0x04; b1->stmts = s; gen_not(b1); /* * AND that with the checks for data and management * frames. */ gen_and(b1, b0); return b0; case Q_DST: /* * Oh, yuk. * * For control frames, there is no DA. * * For management frames, DA is at an * offset of 4 from the beginning of * the packet. * * For data frames, DA is at an offset * of 4 from the beginning of the packet * if To DS is clear and at an offset of * 16 from the beginning of the packet * if To DS is set. */ /* * Generate the tests to be done for data frames. * * First, check for To DS set, i.e. "link[1] & 0x01". */ s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B); b1 = new_block(cstate, JMP(BPF_JSET)); b1->s.k = 0x01; /* To DS */ b1->stmts = s; /* * If To DS is set, the DA is at 16. */ b0 = gen_bcmp(cstate, OR_LINKHDR, 16, 6, eaddr); gen_and(b1, b0); /* * Now, check for To DS not set, i.e. check * "!(link[1] & 0x01)". */ s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B); b2 = new_block(cstate, JMP(BPF_JSET)); b2->s.k = 0x01; /* To DS */ b2->stmts = s; gen_not(b2); /* * If To DS is not set, the DA is at 4. */ b1 = gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr); gen_and(b2, b1); /* * Now OR together the last two checks. That gives * the complete set of checks for data frames. */ gen_or(b1, b0); /* * Now check for a data frame. * I.e, check "link[0] & 0x08". */ s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B); b1 = new_block(cstate, JMP(BPF_JSET)); b1->s.k = 0x08; b1->stmts = s; /* * AND that with the checks done for data frames. */ gen_and(b1, b0); /* * If the high-order bit of the type value is 0, this * is a management frame. * I.e, check "!(link[0] & 0x08)". */ s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B); b2 = new_block(cstate, JMP(BPF_JSET)); b2->s.k = 0x08; b2->stmts = s; gen_not(b2); /* * For management frames, the DA is at 4. */ b1 = gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr); gen_and(b2, b1); /* * OR that with the checks done for data frames. * That gives the checks done for management and * data frames. */ gen_or(b1, b0); /* * If the low-order bit of the type value is 1, * this is either a control frame or a frame * with a reserved type, and thus not a * frame with an SA. * * I.e., check "!(link[0] & 0x04)". */ s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B); b1 = new_block(cstate, JMP(BPF_JSET)); b1->s.k = 0x04; b1->stmts = s; gen_not(b1); /* * AND that with the checks for data and management * frames. */ gen_and(b1, b0); return b0; case Q_AND: b0 = gen_wlanhostop(cstate, eaddr, Q_SRC); b1 = gen_wlanhostop(cstate, eaddr, Q_DST); gen_and(b0, b1); return b1; case Q_DEFAULT: case Q_OR: b0 = gen_wlanhostop(cstate, eaddr, Q_SRC); b1 = gen_wlanhostop(cstate, eaddr, Q_DST); gen_or(b0, b1); return b1; /* * XXX - add BSSID keyword? */ case Q_ADDR1: return (gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr)); case Q_ADDR2: /* * Not present in CTS or ACK control frames. */ b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_TYPE_CTL, IEEE80211_FC0_TYPE_MASK); gen_not(b0); b1 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_CTS, IEEE80211_FC0_SUBTYPE_MASK); gen_not(b1); b2 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_ACK, IEEE80211_FC0_SUBTYPE_MASK); gen_not(b2); gen_and(b1, b2); gen_or(b0, b2); b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr); gen_and(b2, b1); return b1; case Q_ADDR3: /* * Not present in control frames. */ b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_TYPE_CTL, IEEE80211_FC0_TYPE_MASK); gen_not(b0); b1 = gen_bcmp(cstate, OR_LINKHDR, 16, 6, eaddr); gen_and(b0, b1); return b1; case Q_ADDR4: /* * Present only if the direction mask has both "From DS" * and "To DS" set. Neither control frames nor management * frames should have both of those set, so we don't * check the frame type. */ b0 = gen_mcmp(cstate, OR_LINKHDR, 1, BPF_B, IEEE80211_FC1_DIR_DSTODS, IEEE80211_FC1_DIR_MASK); b1 = gen_bcmp(cstate, OR_LINKHDR, 24, 6, eaddr); gen_and(b0, b1); return b1; case Q_RA: /* * Not present in management frames; addr1 in other * frames. */ /* * If the high-order bit of the type value is 0, this * is a management frame. * I.e, check "(link[0] & 0x08)". */ s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B); b1 = new_block(cstate, JMP(BPF_JSET)); b1->s.k = 0x08; b1->stmts = s; /* * Check addr1. */ b0 = gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr); /* * AND that with the check of addr1. */ gen_and(b1, b0); return (b0); case Q_TA: /* * Not present in management frames; addr2, if present, * in other frames. */ /* * Not present in CTS or ACK control frames. */ b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_TYPE_CTL, IEEE80211_FC0_TYPE_MASK); gen_not(b0); b1 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_CTS, IEEE80211_FC0_SUBTYPE_MASK); gen_not(b1); b2 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_ACK, IEEE80211_FC0_SUBTYPE_MASK); gen_not(b2); gen_and(b1, b2); gen_or(b0, b2); /* * If the high-order bit of the type value is 0, this * is a management frame. * I.e, check "(link[0] & 0x08)". */ s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B); b1 = new_block(cstate, JMP(BPF_JSET)); b1->s.k = 0x08; b1->stmts = s; /* * AND that with the check for frames other than * CTS and ACK frames. */ gen_and(b1, b2); /* * Check addr2. */ b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr); gen_and(b2, b1); return b1; } abort(); /*NOTREACHED*/ } /* * Like gen_ehostop, but for RFC 2625 IP-over-Fibre-Channel. * (We assume that the addresses are IEEE 48-bit MAC addresses, * as the RFC states.) */ static struct block * gen_ipfchostop(compiler_state_t *cstate, const u_char *eaddr, int dir) { register struct block *b0, *b1; switch (dir) { case Q_SRC: return gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr); case Q_DST: return gen_bcmp(cstate, OR_LINKHDR, 2, 6, eaddr); case Q_AND: b0 = gen_ipfchostop(cstate, eaddr, Q_SRC); b1 = gen_ipfchostop(cstate, eaddr, Q_DST); gen_and(b0, b1); return b1; case Q_DEFAULT: case Q_OR: b0 = gen_ipfchostop(cstate, eaddr, Q_SRC); b1 = gen_ipfchostop(cstate, eaddr, Q_DST); gen_or(b0, b1); return b1; case Q_ADDR1: bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11"); /*NOTREACHED*/ case Q_ADDR2: bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11"); /*NOTREACHED*/ case Q_ADDR3: bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11"); /*NOTREACHED*/ case Q_ADDR4: bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11"); /*NOTREACHED*/ case Q_RA: bpf_error(cstate, "'ra' is only supported on 802.11"); /*NOTREACHED*/ case Q_TA: bpf_error(cstate, "'ta' is only supported on 802.11"); /*NOTREACHED*/ } abort(); /*NOTREACHED*/ } /* * This is quite tricky because there may be pad bytes in front of the * DECNET header, and then there are two possible data packet formats that * carry both src and dst addresses, plus 5 packet types in a format that * carries only the src node, plus 2 types that use a different format and * also carry just the src node. * * Yuck. * * Instead of doing those all right, we just look for data packets with * 0 or 1 bytes of padding. If you want to look at other packets, that * will require a lot more hacking. * * To add support for filtering on DECNET "areas" (network numbers) * one would want to add a "mask" argument to this routine. That would * make the filter even more inefficient, although one could be clever * and not generate masking instructions if the mask is 0xFFFF. */ static struct block * gen_dnhostop(compiler_state_t *cstate, bpf_u_int32 addr, int dir) { struct block *b0, *b1, *b2, *tmp; u_int offset_lh; /* offset if long header is received */ u_int offset_sh; /* offset if short header is received */ switch (dir) { case Q_DST: offset_sh = 1; /* follows flags */ offset_lh = 7; /* flgs,darea,dsubarea,HIORD */ break; case Q_SRC: offset_sh = 3; /* follows flags, dstnode */ offset_lh = 15; /* flgs,darea,dsubarea,did,sarea,ssub,HIORD */ break; case Q_AND: /* Inefficient because we do our Calvinball dance twice */ b0 = gen_dnhostop(cstate, addr, Q_SRC); b1 = gen_dnhostop(cstate, addr, Q_DST); gen_and(b0, b1); return b1; case Q_DEFAULT: case Q_OR: /* Inefficient because we do our Calvinball dance twice */ b0 = gen_dnhostop(cstate, addr, Q_SRC); b1 = gen_dnhostop(cstate, addr, Q_DST); gen_or(b0, b1); return b1; case Q_ADDR1: bpf_error(cstate, "'addr1' and 'address1' are not valid qualifiers for addresses other than 802.11 MAC addresses"); /*NOTREACHED*/ case Q_ADDR2: bpf_error(cstate, "'addr2' and 'address2' are not valid qualifiers for addresses other than 802.11 MAC addresses"); /*NOTREACHED*/ case Q_ADDR3: bpf_error(cstate, "'addr3' and 'address3' are not valid qualifiers for addresses other than 802.11 MAC addresses"); /*NOTREACHED*/ case Q_ADDR4: bpf_error(cstate, "'addr4' and 'address4' are not valid qualifiers for addresses other than 802.11 MAC addresses"); /*NOTREACHED*/ case Q_RA: bpf_error(cstate, "'ra' is not a valid qualifier for addresses other than 802.11 MAC addresses"); /*NOTREACHED*/ case Q_TA: bpf_error(cstate, "'ta' is not a valid qualifier for addresses other than 802.11 MAC addresses"); /*NOTREACHED*/ default: abort(); /*NOTREACHED*/ } b0 = gen_linktype(cstate, ETHERTYPE_DN); /* Check for pad = 1, long header case */ tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_H, (bpf_u_int32)ntohs(0x0681), (bpf_u_int32)ntohs(0x07FF)); b1 = gen_cmp(cstate, OR_LINKPL, 2 + 1 + offset_lh, BPF_H, (bpf_u_int32)ntohs((u_short)addr)); gen_and(tmp, b1); /* Check for pad = 0, long header case */ tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_B, (bpf_u_int32)0x06, (bpf_u_int32)0x7); b2 = gen_cmp(cstate, OR_LINKPL, 2 + offset_lh, BPF_H, (bpf_u_int32)ntohs((u_short)addr)); gen_and(tmp, b2); gen_or(b2, b1); /* Check for pad = 1, short header case */ tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_H, (bpf_u_int32)ntohs(0x0281), (bpf_u_int32)ntohs(0x07FF)); b2 = gen_cmp(cstate, OR_LINKPL, 2 + 1 + offset_sh, BPF_H, (bpf_u_int32)ntohs((u_short)addr)); gen_and(tmp, b2); gen_or(b2, b1); /* Check for pad = 0, short header case */ tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_B, (bpf_u_int32)0x02, (bpf_u_int32)0x7); b2 = gen_cmp(cstate, OR_LINKPL, 2 + offset_sh, BPF_H, (bpf_u_int32)ntohs((u_short)addr)); gen_and(tmp, b2); gen_or(b2, b1); /* Combine with test for cstate->linktype */ gen_and(b0, b1); return b1; } /* * Generate a check for IPv4 or IPv6 for MPLS-encapsulated packets; * test the bottom-of-stack bit, and then check the version number * field in the IP header. */ static struct block * gen_mpls_linktype(compiler_state_t *cstate, bpf_u_int32 ll_proto) { struct block *b0, *b1; switch (ll_proto) { case ETHERTYPE_IP: /* match the bottom-of-stack bit */ b0 = gen_mcmp(cstate, OR_LINKPL, (u_int)-2, BPF_B, 0x01, 0x01); /* match the IPv4 version number */ b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_B, 0x40, 0xf0); gen_and(b0, b1); return b1; case ETHERTYPE_IPV6: /* match the bottom-of-stack bit */ b0 = gen_mcmp(cstate, OR_LINKPL, (u_int)-2, BPF_B, 0x01, 0x01); /* match the IPv4 version number */ b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_B, 0x60, 0xf0); gen_and(b0, b1); return b1; default: /* FIXME add other L3 proto IDs */ bpf_error(cstate, "unsupported protocol over mpls"); /*NOTREACHED*/ } } static struct block * gen_host(compiler_state_t *cstate, bpf_u_int32 addr, bpf_u_int32 mask, int proto, int dir, int type) { struct block *b0, *b1; const char *typestr; if (type == Q_NET) typestr = "net"; else typestr = "host"; switch (proto) { case Q_DEFAULT: b0 = gen_host(cstate, addr, mask, Q_IP, dir, type); /* * Only check for non-IPv4 addresses if we're not * checking MPLS-encapsulated packets. */ if (cstate->label_stack_depth == 0) { b1 = gen_host(cstate, addr, mask, Q_ARP, dir, type); gen_or(b0, b1); b0 = gen_host(cstate, addr, mask, Q_RARP, dir, type); gen_or(b1, b0); } return b0; case Q_LINK: bpf_error(cstate, "link-layer modifier applied to %s", typestr); case Q_IP: return gen_hostop(cstate, addr, mask, dir, ETHERTYPE_IP, 12, 16); case Q_RARP: return gen_hostop(cstate, addr, mask, dir, ETHERTYPE_REVARP, 14, 24); case Q_ARP: return gen_hostop(cstate, addr, mask, dir, ETHERTYPE_ARP, 14, 24); case Q_SCTP: bpf_error(cstate, "'sctp' modifier applied to %s", typestr); case Q_TCP: bpf_error(cstate, "'tcp' modifier applied to %s", typestr); case Q_UDP: bpf_error(cstate, "'udp' modifier applied to %s", typestr); case Q_ICMP: bpf_error(cstate, "'icmp' modifier applied to %s", typestr); case Q_IGMP: bpf_error(cstate, "'igmp' modifier applied to %s", typestr); case Q_IGRP: bpf_error(cstate, "'igrp' modifier applied to %s", typestr); case Q_ATALK: bpf_error(cstate, "AppleTalk host filtering not implemented"); case Q_DECNET: return gen_dnhostop(cstate, addr, dir); case Q_LAT: bpf_error(cstate, "LAT host filtering not implemented"); case Q_SCA: bpf_error(cstate, "SCA host filtering not implemented"); case Q_MOPRC: bpf_error(cstate, "MOPRC host filtering not implemented"); case Q_MOPDL: bpf_error(cstate, "MOPDL host filtering not implemented"); case Q_IPV6: bpf_error(cstate, "'ip6' modifier applied to ip host"); case Q_ICMPV6: bpf_error(cstate, "'icmp6' modifier applied to %s", typestr); case Q_AH: bpf_error(cstate, "'ah' modifier applied to %s", typestr); case Q_ESP: bpf_error(cstate, "'esp' modifier applied to %s", typestr); case Q_PIM: bpf_error(cstate, "'pim' modifier applied to %s", typestr); case Q_VRRP: bpf_error(cstate, "'vrrp' modifier applied to %s", typestr); case Q_AARP: bpf_error(cstate, "AARP host filtering not implemented"); case Q_ISO: bpf_error(cstate, "ISO host filtering not implemented"); case Q_ESIS: bpf_error(cstate, "'esis' modifier applied to %s", typestr); case Q_ISIS: bpf_error(cstate, "'isis' modifier applied to %s", typestr); case Q_CLNP: bpf_error(cstate, "'clnp' modifier applied to %s", typestr); case Q_STP: bpf_error(cstate, "'stp' modifier applied to %s", typestr); case Q_IPX: bpf_error(cstate, "IPX host filtering not implemented"); case Q_NETBEUI: bpf_error(cstate, "'netbeui' modifier applied to %s", typestr); case Q_ISIS_L1: bpf_error(cstate, "'l1' modifier applied to %s", typestr); case Q_ISIS_L2: bpf_error(cstate, "'l2' modifier applied to %s", typestr); case Q_ISIS_IIH: bpf_error(cstate, "'iih' modifier applied to %s", typestr); case Q_ISIS_SNP: bpf_error(cstate, "'snp' modifier applied to %s", typestr); case Q_ISIS_CSNP: bpf_error(cstate, "'csnp' modifier applied to %s", typestr); case Q_ISIS_PSNP: bpf_error(cstate, "'psnp' modifier applied to %s", typestr); case Q_ISIS_LSP: bpf_error(cstate, "'lsp' modifier applied to %s", typestr); case Q_RADIO: bpf_error(cstate, "'radio' modifier applied to %s", typestr); case Q_CARP: bpf_error(cstate, "'carp' modifier applied to %s", typestr); default: abort(); } /*NOTREACHED*/ } #ifdef INET6 static struct block * gen_host6(compiler_state_t *cstate, struct in6_addr *addr, struct in6_addr *mask, int proto, int dir, int type) { const char *typestr; if (type == Q_NET) typestr = "net"; else typestr = "host"; switch (proto) { case Q_DEFAULT: return gen_host6(cstate, addr, mask, Q_IPV6, dir, type); case Q_LINK: bpf_error(cstate, "link-layer modifier applied to ip6 %s", typestr); case Q_IP: bpf_error(cstate, "'ip' modifier applied to ip6 %s", typestr); case Q_RARP: bpf_error(cstate, "'rarp' modifier applied to ip6 %s", typestr); case Q_ARP: bpf_error(cstate, "'arp' modifier applied to ip6 %s", typestr); case Q_SCTP: bpf_error(cstate, "'sctp' modifier applied to ip6 %s", typestr); case Q_TCP: bpf_error(cstate, "'tcp' modifier applied to ip6 %s", typestr); case Q_UDP: bpf_error(cstate, "'udp' modifier applied to ip6 %s", typestr); case Q_ICMP: bpf_error(cstate, "'icmp' modifier applied to ip6 %s", typestr); case Q_IGMP: bpf_error(cstate, "'igmp' modifier applied to ip6 %s", typestr); case Q_IGRP: bpf_error(cstate, "'igrp' modifier applied to ip6 %s", typestr); case Q_ATALK: bpf_error(cstate, "AppleTalk modifier applied to ip6 %s", typestr); case Q_DECNET: bpf_error(cstate, "'decnet' modifier applied to ip6 %s", typestr); case Q_LAT: bpf_error(cstate, "'lat' modifier applied to ip6 %s", typestr); case Q_SCA: bpf_error(cstate, "'sca' modifier applied to ip6 %s", typestr); case Q_MOPRC: bpf_error(cstate, "'moprc' modifier applied to ip6 %s", typestr); case Q_MOPDL: bpf_error(cstate, "'mopdl' modifier applied to ip6 %s", typestr); case Q_IPV6: return gen_hostop6(cstate, addr, mask, dir, ETHERTYPE_IPV6, 8, 24); case Q_ICMPV6: bpf_error(cstate, "'icmp6' modifier applied to ip6 %s", typestr); case Q_AH: bpf_error(cstate, "'ah' modifier applied to ip6 %s", typestr); case Q_ESP: bpf_error(cstate, "'esp' modifier applied to ip6 %s", typestr); case Q_PIM: bpf_error(cstate, "'pim' modifier applied to ip6 %s", typestr); case Q_VRRP: bpf_error(cstate, "'vrrp' modifier applied to ip6 %s", typestr); case Q_AARP: bpf_error(cstate, "'aarp' modifier applied to ip6 %s", typestr); case Q_ISO: bpf_error(cstate, "'iso' modifier applied to ip6 %s", typestr); case Q_ESIS: bpf_error(cstate, "'esis' modifier applied to ip6 %s", typestr); case Q_ISIS: bpf_error(cstate, "'isis' modifier applied to ip6 %s", typestr); case Q_CLNP: bpf_error(cstate, "'clnp' modifier applied to ip6 %s", typestr); case Q_STP: bpf_error(cstate, "'stp' modifier applied to ip6 %s", typestr); case Q_IPX: bpf_error(cstate, "'ipx' modifier applied to ip6 %s", typestr); case Q_NETBEUI: bpf_error(cstate, "'netbeui' modifier applied to ip6 %s", typestr); case Q_ISIS_L1: bpf_error(cstate, "'l1' modifier applied to ip6 %s", typestr); case Q_ISIS_L2: bpf_error(cstate, "'l2' modifier applied to ip6 %s", typestr); case Q_ISIS_IIH: bpf_error(cstate, "'iih' modifier applied to ip6 %s", typestr); case Q_ISIS_SNP: bpf_error(cstate, "'snp' modifier applied to ip6 %s", typestr); case Q_ISIS_CSNP: bpf_error(cstate, "'csnp' modifier applied to ip6 %s", typestr); case Q_ISIS_PSNP: bpf_error(cstate, "'psnp' modifier applied to ip6 %s", typestr); case Q_ISIS_LSP: bpf_error(cstate, "'lsp' modifier applied to ip6 %s", typestr); case Q_RADIO: bpf_error(cstate, "'radio' modifier applied to ip6 %s", typestr); case Q_CARP: bpf_error(cstate, "'carp' modifier applied to ip6 %s", typestr); default: abort(); } /*NOTREACHED*/ } #endif #ifndef INET6 static struct block * gen_gateway(compiler_state_t *cstate, const u_char *eaddr, struct addrinfo *alist, int proto, int dir) { struct block *b0, *b1, *tmp; struct addrinfo *ai; struct sockaddr_in *sin; if (dir != 0) bpf_error(cstate, "direction applied to 'gateway'"); switch (proto) { case Q_DEFAULT: case Q_IP: case Q_ARP: case Q_RARP: switch (cstate->linktype) { case DLT_EN10MB: case DLT_NETANALYZER: case DLT_NETANALYZER_TRANSPARENT: b1 = gen_prevlinkhdr_check(cstate); b0 = gen_ehostop(cstate, eaddr, Q_OR); if (b1 != NULL) gen_and(b1, b0); break; case DLT_FDDI: b0 = gen_fhostop(cstate, eaddr, Q_OR); break; case DLT_IEEE802: b0 = gen_thostop(cstate, eaddr, Q_OR); break; case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO_AVS: case DLT_IEEE802_11_RADIO: case DLT_PPI: b0 = gen_wlanhostop(cstate, eaddr, Q_OR); break; case DLT_SUNATM: /* * This is LLC-multiplexed traffic; if it were * LANE, cstate->linktype would have been set to * DLT_EN10MB. */ bpf_error(cstate, "'gateway' supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel"); break; case DLT_IP_OVER_FC: b0 = gen_ipfchostop(cstate, eaddr, Q_OR); break; default: bpf_error(cstate, "'gateway' supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel"); } b1 = NULL; for (ai = alist; ai != NULL; ai = ai->ai_next) { /* * Does it have an address? */ if (ai->ai_addr != NULL) { /* * Yes. Is it an IPv4 address? */ if (ai->ai_addr->sa_family == AF_INET) { /* * Generate an entry for it. */ sin = (struct sockaddr_in *)ai->ai_addr; tmp = gen_host(cstate, ntohl(sin->sin_addr.s_addr), 0xffffffff, proto, Q_OR, Q_HOST); /* * Is it the *first* IPv4 address? */ if (b1 == NULL) { /* * Yes, so start with it. */ b1 = tmp; } else { /* * No, so OR it into the * existing set of * addresses. */ gen_or(b1, tmp); b1 = tmp; } } } } if (b1 == NULL) { /* * No IPv4 addresses found. */ return (NULL); } gen_not(b1); gen_and(b0, b1); return b1; } bpf_error(cstate, "illegal modifier of 'gateway'"); /*NOTREACHED*/ } #endif static struct block * gen_proto_abbrev_internal(compiler_state_t *cstate, int proto) { struct block *b0; struct block *b1; switch (proto) { case Q_SCTP: b1 = gen_proto(cstate, IPPROTO_SCTP, Q_DEFAULT, Q_DEFAULT); break; case Q_TCP: b1 = gen_proto(cstate, IPPROTO_TCP, Q_DEFAULT, Q_DEFAULT); break; case Q_UDP: b1 = gen_proto(cstate, IPPROTO_UDP, Q_DEFAULT, Q_DEFAULT); break; case Q_ICMP: b1 = gen_proto(cstate, IPPROTO_ICMP, Q_IP, Q_DEFAULT); break; #ifndef IPPROTO_IGMP #define IPPROTO_IGMP 2 #endif case Q_IGMP: b1 = gen_proto(cstate, IPPROTO_IGMP, Q_IP, Q_DEFAULT); break; #ifndef IPPROTO_IGRP #define IPPROTO_IGRP 9 #endif case Q_IGRP: b1 = gen_proto(cstate, IPPROTO_IGRP, Q_IP, Q_DEFAULT); break; #ifndef IPPROTO_PIM #define IPPROTO_PIM 103 #endif case Q_PIM: b1 = gen_proto(cstate, IPPROTO_PIM, Q_DEFAULT, Q_DEFAULT); break; #ifndef IPPROTO_VRRP #define IPPROTO_VRRP 112 #endif case Q_VRRP: b1 = gen_proto(cstate, IPPROTO_VRRP, Q_IP, Q_DEFAULT); break; #ifndef IPPROTO_CARP #define IPPROTO_CARP 112 #endif case Q_CARP: b1 = gen_proto(cstate, IPPROTO_CARP, Q_IP, Q_DEFAULT); break; case Q_IP: b1 = gen_linktype(cstate, ETHERTYPE_IP); break; case Q_ARP: b1 = gen_linktype(cstate, ETHERTYPE_ARP); break; case Q_RARP: b1 = gen_linktype(cstate, ETHERTYPE_REVARP); break; case Q_LINK: bpf_error(cstate, "link layer applied in wrong context"); case Q_ATALK: b1 = gen_linktype(cstate, ETHERTYPE_ATALK); break; case Q_AARP: b1 = gen_linktype(cstate, ETHERTYPE_AARP); break; case Q_DECNET: b1 = gen_linktype(cstate, ETHERTYPE_DN); break; case Q_SCA: b1 = gen_linktype(cstate, ETHERTYPE_SCA); break; case Q_LAT: b1 = gen_linktype(cstate, ETHERTYPE_LAT); break; case Q_MOPDL: b1 = gen_linktype(cstate, ETHERTYPE_MOPDL); break; case Q_MOPRC: b1 = gen_linktype(cstate, ETHERTYPE_MOPRC); break; case Q_IPV6: b1 = gen_linktype(cstate, ETHERTYPE_IPV6); break; #ifndef IPPROTO_ICMPV6 #define IPPROTO_ICMPV6 58 #endif case Q_ICMPV6: b1 = gen_proto(cstate, IPPROTO_ICMPV6, Q_IPV6, Q_DEFAULT); break; #ifndef IPPROTO_AH #define IPPROTO_AH 51 #endif case Q_AH: b1 = gen_proto(cstate, IPPROTO_AH, Q_DEFAULT, Q_DEFAULT); break; #ifndef IPPROTO_ESP #define IPPROTO_ESP 50 #endif case Q_ESP: b1 = gen_proto(cstate, IPPROTO_ESP, Q_DEFAULT, Q_DEFAULT); break; case Q_ISO: b1 = gen_linktype(cstate, LLCSAP_ISONS); break; case Q_ESIS: b1 = gen_proto(cstate, ISO9542_ESIS, Q_ISO, Q_DEFAULT); break; case Q_ISIS: b1 = gen_proto(cstate, ISO10589_ISIS, Q_ISO, Q_DEFAULT); break; case Q_ISIS_L1: /* all IS-IS Level1 PDU-Types */ b0 = gen_proto(cstate, ISIS_L1_LAN_IIH, Q_ISIS, Q_DEFAULT); b1 = gen_proto(cstate, ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); /* FIXME extract the circuit-type bits */ gen_or(b0, b1); b0 = gen_proto(cstate, ISIS_L1_LSP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); b0 = gen_proto(cstate, ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); b0 = gen_proto(cstate, ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); break; case Q_ISIS_L2: /* all IS-IS Level2 PDU-Types */ b0 = gen_proto(cstate, ISIS_L2_LAN_IIH, Q_ISIS, Q_DEFAULT); b1 = gen_proto(cstate, ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); /* FIXME extract the circuit-type bits */ gen_or(b0, b1); b0 = gen_proto(cstate, ISIS_L2_LSP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); b0 = gen_proto(cstate, ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); b0 = gen_proto(cstate, ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); break; case Q_ISIS_IIH: /* all IS-IS Hello PDU-Types */ b0 = gen_proto(cstate, ISIS_L1_LAN_IIH, Q_ISIS, Q_DEFAULT); b1 = gen_proto(cstate, ISIS_L2_LAN_IIH, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); b0 = gen_proto(cstate, ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); break; case Q_ISIS_LSP: b0 = gen_proto(cstate, ISIS_L1_LSP, Q_ISIS, Q_DEFAULT); b1 = gen_proto(cstate, ISIS_L2_LSP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); break; case Q_ISIS_SNP: b0 = gen_proto(cstate, ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT); b1 = gen_proto(cstate, ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); b0 = gen_proto(cstate, ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); b0 = gen_proto(cstate, ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); break; case Q_ISIS_CSNP: b0 = gen_proto(cstate, ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT); b1 = gen_proto(cstate, ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); break; case Q_ISIS_PSNP: b0 = gen_proto(cstate, ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT); b1 = gen_proto(cstate, ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); break; case Q_CLNP: b1 = gen_proto(cstate, ISO8473_CLNP, Q_ISO, Q_DEFAULT); break; case Q_STP: b1 = gen_linktype(cstate, LLCSAP_8021D); break; case Q_IPX: b1 = gen_linktype(cstate, LLCSAP_IPX); break; case Q_NETBEUI: b1 = gen_linktype(cstate, LLCSAP_NETBEUI); break; case Q_RADIO: bpf_error(cstate, "'radio' is not a valid protocol type"); default: abort(); } return b1; } struct block * gen_proto_abbrev(compiler_state_t *cstate, int proto) { /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); return gen_proto_abbrev_internal(cstate, proto); } static struct block * gen_ipfrag(compiler_state_t *cstate) { struct slist *s; struct block *b; /* not IPv4 frag other than the first frag */ s = gen_load_a(cstate, OR_LINKPL, 6, BPF_H); b = new_block(cstate, JMP(BPF_JSET)); b->s.k = 0x1fff; b->stmts = s; gen_not(b); return b; } /* * Generate a comparison to a port value in the transport-layer header * at the specified offset from the beginning of that header. * * XXX - this handles a variable-length prefix preceding the link-layer * header, such as the radiotap or AVS radio prefix, but doesn't handle * variable-length link-layer headers (such as Token Ring or 802.11 * headers). */ static struct block * gen_portatom(compiler_state_t *cstate, int off, bpf_u_int32 v) { return gen_cmp(cstate, OR_TRAN_IPV4, off, BPF_H, v); } static struct block * gen_portatom6(compiler_state_t *cstate, int off, bpf_u_int32 v) { return gen_cmp(cstate, OR_TRAN_IPV6, off, BPF_H, v); } static struct block * gen_portop(compiler_state_t *cstate, u_int port, u_int proto, int dir) { struct block *b0, *b1, *tmp; /* ip proto 'proto' and not a fragment other than the first fragment */ tmp = gen_cmp(cstate, OR_LINKPL, 9, BPF_B, proto); b0 = gen_ipfrag(cstate); gen_and(tmp, b0); switch (dir) { case Q_SRC: b1 = gen_portatom(cstate, 0, port); break; case Q_DST: b1 = gen_portatom(cstate, 2, port); break; case Q_AND: tmp = gen_portatom(cstate, 0, port); b1 = gen_portatom(cstate, 2, port); gen_and(tmp, b1); break; case Q_DEFAULT: case Q_OR: tmp = gen_portatom(cstate, 0, port); b1 = gen_portatom(cstate, 2, port); gen_or(tmp, b1); break; case Q_ADDR1: bpf_error(cstate, "'addr1' and 'address1' are not valid qualifiers for ports"); /*NOTREACHED*/ case Q_ADDR2: bpf_error(cstate, "'addr2' and 'address2' are not valid qualifiers for ports"); /*NOTREACHED*/ case Q_ADDR3: bpf_error(cstate, "'addr3' and 'address3' are not valid qualifiers for ports"); /*NOTREACHED*/ case Q_ADDR4: bpf_error(cstate, "'addr4' and 'address4' are not valid qualifiers for ports"); /*NOTREACHED*/ case Q_RA: bpf_error(cstate, "'ra' is not a valid qualifier for ports"); /*NOTREACHED*/ case Q_TA: bpf_error(cstate, "'ta' is not a valid qualifier for ports"); /*NOTREACHED*/ default: abort(); /*NOTREACHED*/ } gen_and(b0, b1); return b1; } static struct block * gen_port(compiler_state_t *cstate, u_int port, int ip_proto, int dir) { struct block *b0, *b1, *tmp; /* * ether proto ip * * For FDDI, RFC 1188 says that SNAP encapsulation is used, * not LLC encapsulation with LLCSAP_IP. * * For IEEE 802 networks - which includes 802.5 token ring * (which is what DLT_IEEE802 means) and 802.11 - RFC 1042 * says that SNAP encapsulation is used, not LLC encapsulation * with LLCSAP_IP. * * For LLC-encapsulated ATM/"Classical IP", RFC 1483 and * RFC 2225 say that SNAP encapsulation is used, not LLC * encapsulation with LLCSAP_IP. * * So we always check for ETHERTYPE_IP. */ b0 = gen_linktype(cstate, ETHERTYPE_IP); switch (ip_proto) { case IPPROTO_UDP: case IPPROTO_TCP: case IPPROTO_SCTP: b1 = gen_portop(cstate, port, (u_int)ip_proto, dir); break; case PROTO_UNDEF: tmp = gen_portop(cstate, port, IPPROTO_TCP, dir); b1 = gen_portop(cstate, port, IPPROTO_UDP, dir); gen_or(tmp, b1); tmp = gen_portop(cstate, port, IPPROTO_SCTP, dir); gen_or(tmp, b1); break; default: abort(); } gen_and(b0, b1); return b1; } struct block * gen_portop6(compiler_state_t *cstate, u_int port, u_int proto, int dir) { struct block *b0, *b1, *tmp; /* ip6 proto 'proto' */ /* XXX - catch the first fragment of a fragmented packet? */ b0 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, proto); switch (dir) { case Q_SRC: b1 = gen_portatom6(cstate, 0, port); break; case Q_DST: b1 = gen_portatom6(cstate, 2, port); break; case Q_AND: tmp = gen_portatom6(cstate, 0, port); b1 = gen_portatom6(cstate, 2, port); gen_and(tmp, b1); break; case Q_DEFAULT: case Q_OR: tmp = gen_portatom6(cstate, 0, port); b1 = gen_portatom6(cstate, 2, port); gen_or(tmp, b1); break; default: abort(); } gen_and(b0, b1); return b1; } static struct block * gen_port6(compiler_state_t *cstate, u_int port, int ip_proto, int dir) { struct block *b0, *b1, *tmp; /* link proto ip6 */ b0 = gen_linktype(cstate, ETHERTYPE_IPV6); switch (ip_proto) { case IPPROTO_UDP: case IPPROTO_TCP: case IPPROTO_SCTP: b1 = gen_portop6(cstate, port, (u_int)ip_proto, dir); break; case PROTO_UNDEF: tmp = gen_portop6(cstate, port, IPPROTO_TCP, dir); b1 = gen_portop6(cstate, port, IPPROTO_UDP, dir); gen_or(tmp, b1); tmp = gen_portop6(cstate, port, IPPROTO_SCTP, dir); gen_or(tmp, b1); break; default: abort(); } gen_and(b0, b1); return b1; } /* gen_portrange code */ static struct block * gen_portrangeatom(compiler_state_t *cstate, u_int off, bpf_u_int32 v1, bpf_u_int32 v2) { struct block *b1, *b2; if (v1 > v2) { /* * Reverse the order of the ports, so v1 is the lower one. */ bpf_u_int32 vtemp; vtemp = v1; v1 = v2; v2 = vtemp; } b1 = gen_cmp_ge(cstate, OR_TRAN_IPV4, off, BPF_H, v1); b2 = gen_cmp_le(cstate, OR_TRAN_IPV4, off, BPF_H, v2); gen_and(b1, b2); return b2; } static struct block * gen_portrangeop(compiler_state_t *cstate, u_int port1, u_int port2, bpf_u_int32 proto, int dir) { struct block *b0, *b1, *tmp; /* ip proto 'proto' and not a fragment other than the first fragment */ tmp = gen_cmp(cstate, OR_LINKPL, 9, BPF_B, proto); b0 = gen_ipfrag(cstate); gen_and(tmp, b0); switch (dir) { case Q_SRC: b1 = gen_portrangeatom(cstate, 0, port1, port2); break; case Q_DST: b1 = gen_portrangeatom(cstate, 2, port1, port2); break; case Q_AND: tmp = gen_portrangeatom(cstate, 0, port1, port2); b1 = gen_portrangeatom(cstate, 2, port1, port2); gen_and(tmp, b1); break; case Q_DEFAULT: case Q_OR: tmp = gen_portrangeatom(cstate, 0, port1, port2); b1 = gen_portrangeatom(cstate, 2, port1, port2); gen_or(tmp, b1); break; case Q_ADDR1: bpf_error(cstate, "'addr1' and 'address1' are not valid qualifiers for port ranges"); /*NOTREACHED*/ case Q_ADDR2: bpf_error(cstate, "'addr2' and 'address2' are not valid qualifiers for port ranges"); /*NOTREACHED*/ case Q_ADDR3: bpf_error(cstate, "'addr3' and 'address3' are not valid qualifiers for port ranges"); /*NOTREACHED*/ case Q_ADDR4: bpf_error(cstate, "'addr4' and 'address4' are not valid qualifiers for port ranges"); /*NOTREACHED*/ case Q_RA: bpf_error(cstate, "'ra' is not a valid qualifier for port ranges"); /*NOTREACHED*/ case Q_TA: bpf_error(cstate, "'ta' is not a valid qualifier for port ranges"); /*NOTREACHED*/ default: abort(); /*NOTREACHED*/ } gen_and(b0, b1); return b1; } static struct block * gen_portrange(compiler_state_t *cstate, u_int port1, u_int port2, int ip_proto, int dir) { struct block *b0, *b1, *tmp; /* link proto ip */ b0 = gen_linktype(cstate, ETHERTYPE_IP); switch (ip_proto) { case IPPROTO_UDP: case IPPROTO_TCP: case IPPROTO_SCTP: b1 = gen_portrangeop(cstate, port1, port2, (bpf_u_int32)ip_proto, dir); break; case PROTO_UNDEF: tmp = gen_portrangeop(cstate, port1, port2, IPPROTO_TCP, dir); b1 = gen_portrangeop(cstate, port1, port2, IPPROTO_UDP, dir); gen_or(tmp, b1); tmp = gen_portrangeop(cstate, port1, port2, IPPROTO_SCTP, dir); gen_or(tmp, b1); break; default: abort(); } gen_and(b0, b1); return b1; } static struct block * gen_portrangeatom6(compiler_state_t *cstate, u_int off, bpf_u_int32 v1, bpf_u_int32 v2) { struct block *b1, *b2; if (v1 > v2) { /* * Reverse the order of the ports, so v1 is the lower one. */ bpf_u_int32 vtemp; vtemp = v1; v1 = v2; v2 = vtemp; } b1 = gen_cmp_ge(cstate, OR_TRAN_IPV6, off, BPF_H, v1); b2 = gen_cmp_le(cstate, OR_TRAN_IPV6, off, BPF_H, v2); gen_and(b1, b2); return b2; } static struct block * gen_portrangeop6(compiler_state_t *cstate, u_int port1, u_int port2, bpf_u_int32 proto, int dir) { struct block *b0, *b1, *tmp; /* ip6 proto 'proto' */ /* XXX - catch the first fragment of a fragmented packet? */ b0 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, proto); switch (dir) { case Q_SRC: b1 = gen_portrangeatom6(cstate, 0, port1, port2); break; case Q_DST: b1 = gen_portrangeatom6(cstate, 2, port1, port2); break; case Q_AND: tmp = gen_portrangeatom6(cstate, 0, port1, port2); b1 = gen_portrangeatom6(cstate, 2, port1, port2); gen_and(tmp, b1); break; case Q_DEFAULT: case Q_OR: tmp = gen_portrangeatom6(cstate, 0, port1, port2); b1 = gen_portrangeatom6(cstate, 2, port1, port2); gen_or(tmp, b1); break; default: abort(); } gen_and(b0, b1); return b1; } static struct block * gen_portrange6(compiler_state_t *cstate, u_int port1, u_int port2, int ip_proto, int dir) { struct block *b0, *b1, *tmp; /* link proto ip6 */ b0 = gen_linktype(cstate, ETHERTYPE_IPV6); switch (ip_proto) { case IPPROTO_UDP: case IPPROTO_TCP: case IPPROTO_SCTP: b1 = gen_portrangeop6(cstate, port1, port2, (bpf_u_int32)ip_proto, dir); break; case PROTO_UNDEF: tmp = gen_portrangeop6(cstate, port1, port2, IPPROTO_TCP, dir); b1 = gen_portrangeop6(cstate, port1, port2, IPPROTO_UDP, dir); gen_or(tmp, b1); tmp = gen_portrangeop6(cstate, port1, port2, IPPROTO_SCTP, dir); gen_or(tmp, b1); break; default: abort(); } gen_and(b0, b1); return b1; } static int lookup_proto(compiler_state_t *cstate, const char *name, int proto) { register int v; switch (proto) { case Q_DEFAULT: case Q_IP: case Q_IPV6: v = pcap_nametoproto(name); if (v == PROTO_UNDEF) bpf_error(cstate, "unknown ip proto '%s'", name); break; case Q_LINK: /* XXX should look up h/w protocol type based on cstate->linktype */ v = pcap_nametoeproto(name); if (v == PROTO_UNDEF) { v = pcap_nametollc(name); if (v == PROTO_UNDEF) bpf_error(cstate, "unknown ether proto '%s'", name); } break; case Q_ISO: if (strcmp(name, "esis") == 0) v = ISO9542_ESIS; else if (strcmp(name, "isis") == 0) v = ISO10589_ISIS; else if (strcmp(name, "clnp") == 0) v = ISO8473_CLNP; else bpf_error(cstate, "unknown osi proto '%s'", name); break; default: v = PROTO_UNDEF; break; } return v; } #if !defined(NO_PROTOCHAIN) static struct block * gen_protochain(compiler_state_t *cstate, bpf_u_int32 v, int proto) { struct block *b0, *b; struct slist *s[100]; int fix2, fix3, fix4, fix5; int ahcheck, again, end; int i, max; int reg2 = alloc_reg(cstate); memset(s, 0, sizeof(s)); fix3 = fix4 = fix5 = 0; switch (proto) { case Q_IP: case Q_IPV6: break; case Q_DEFAULT: b0 = gen_protochain(cstate, v, Q_IP); b = gen_protochain(cstate, v, Q_IPV6); gen_or(b0, b); return b; default: bpf_error(cstate, "bad protocol applied for 'protochain'"); /*NOTREACHED*/ } /* * We don't handle variable-length prefixes before the link-layer * header, or variable-length link-layer headers, here yet. * We might want to add BPF instructions to do the protochain * work, to simplify that and, on platforms that have a BPF * interpreter with the new instructions, let the filtering * be done in the kernel. (We already require a modified BPF * engine to do the protochain stuff, to support backward * branches, and backward branch support is unlikely to appear * in kernel BPF engines.) */ if (cstate->off_linkpl.is_variable) bpf_error(cstate, "'protochain' not supported with variable length headers"); /* * To quote a comment in optimize.c: * * "These data structures are used in a Cocke and Shwarz style * value numbering scheme. Since the flowgraph is acyclic, * exit values can be propagated from a node's predecessors * provided it is uniquely defined." * * "Acyclic" means "no backward branches", which means "no * loops", so we have to turn the optimizer off. */ cstate->no_optimize = 1; /* * s[0] is a dummy entry to protect other BPF insn from damage * by s[fix] = foo with uninitialized variable "fix". It is somewhat * hard to find interdependency made by jump table fixup. */ i = 0; s[i] = new_stmt(cstate, 0); /*dummy*/ i++; switch (proto) { case Q_IP: b0 = gen_linktype(cstate, ETHERTYPE_IP); /* A = ip->ip_p */ s[i] = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B); s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 9; i++; /* X = ip->ip_hl << 2 */ s[i] = new_stmt(cstate, BPF_LDX|BPF_MSH|BPF_B); s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl; i++; break; case Q_IPV6: b0 = gen_linktype(cstate, ETHERTYPE_IPV6); /* A = ip6->ip_nxt */ s[i] = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B); s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 6; i++; /* X = sizeof(struct ip6_hdr) */ s[i] = new_stmt(cstate, BPF_LDX|BPF_IMM); s[i]->s.k = 40; i++; break; default: bpf_error(cstate, "unsupported proto to gen_protochain"); /*NOTREACHED*/ } /* again: if (A == v) goto end; else fall through; */ again = i; s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K); s[i]->s.k = v; s[i]->s.jt = NULL; /*later*/ s[i]->s.jf = NULL; /*update in next stmt*/ fix5 = i; i++; #ifndef IPPROTO_NONE #define IPPROTO_NONE 59 #endif /* if (A == IPPROTO_NONE) goto end */ s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K); s[i]->s.jt = NULL; /*later*/ s[i]->s.jf = NULL; /*update in next stmt*/ s[i]->s.k = IPPROTO_NONE; s[fix5]->s.jf = s[i]; fix2 = i; i++; if (proto == Q_IPV6) { int v6start, v6end, v6advance, j; v6start = i; /* if (A == IPPROTO_HOPOPTS) goto v6advance */ s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K); s[i]->s.jt = NULL; /*later*/ s[i]->s.jf = NULL; /*update in next stmt*/ s[i]->s.k = IPPROTO_HOPOPTS; s[fix2]->s.jf = s[i]; i++; /* if (A == IPPROTO_DSTOPTS) goto v6advance */ s[i - 1]->s.jf = s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K); s[i]->s.jt = NULL; /*later*/ s[i]->s.jf = NULL; /*update in next stmt*/ s[i]->s.k = IPPROTO_DSTOPTS; i++; /* if (A == IPPROTO_ROUTING) goto v6advance */ s[i - 1]->s.jf = s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K); s[i]->s.jt = NULL; /*later*/ s[i]->s.jf = NULL; /*update in next stmt*/ s[i]->s.k = IPPROTO_ROUTING; i++; /* if (A == IPPROTO_FRAGMENT) goto v6advance; else goto ahcheck; */ s[i - 1]->s.jf = s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K); s[i]->s.jt = NULL; /*later*/ s[i]->s.jf = NULL; /*later*/ s[i]->s.k = IPPROTO_FRAGMENT; fix3 = i; v6end = i; i++; /* v6advance: */ v6advance = i; /* * in short, * A = P[X + packet head]; * X = X + (P[X + packet head + 1] + 1) * 8; */ /* A = P[X + packet head] */ s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B); s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl; i++; /* MEM[reg2] = A */ s[i] = new_stmt(cstate, BPF_ST); s[i]->s.k = reg2; i++; /* A = P[X + packet head + 1]; */ s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B); s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 1; i++; /* A += 1 */ s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K); s[i]->s.k = 1; i++; /* A *= 8 */ s[i] = new_stmt(cstate, BPF_ALU|BPF_MUL|BPF_K); s[i]->s.k = 8; i++; /* A += X */ s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X); s[i]->s.k = 0; i++; /* X = A; */ s[i] = new_stmt(cstate, BPF_MISC|BPF_TAX); i++; /* A = MEM[reg2] */ s[i] = new_stmt(cstate, BPF_LD|BPF_MEM); s[i]->s.k = reg2; i++; /* goto again; (must use BPF_JA for backward jump) */ s[i] = new_stmt(cstate, BPF_JMP|BPF_JA); s[i]->s.k = again - i - 1; s[i - 1]->s.jf = s[i]; i++; /* fixup */ for (j = v6start; j <= v6end; j++) s[j]->s.jt = s[v6advance]; } else { /* nop */ s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K); s[i]->s.k = 0; s[fix2]->s.jf = s[i]; i++; } /* ahcheck: */ ahcheck = i; /* if (A == IPPROTO_AH) then fall through; else goto end; */ s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K); s[i]->s.jt = NULL; /*later*/ s[i]->s.jf = NULL; /*later*/ s[i]->s.k = IPPROTO_AH; if (fix3) s[fix3]->s.jf = s[ahcheck]; fix4 = i; i++; /* * in short, * A = P[X]; * X = X + (P[X + 1] + 2) * 4; */ /* A = X */ s[i - 1]->s.jt = s[i] = new_stmt(cstate, BPF_MISC|BPF_TXA); i++; /* A = P[X + packet head]; */ s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B); s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl; i++; /* MEM[reg2] = A */ s[i] = new_stmt(cstate, BPF_ST); s[i]->s.k = reg2; i++; /* A = X */ s[i - 1]->s.jt = s[i] = new_stmt(cstate, BPF_MISC|BPF_TXA); i++; /* A += 1 */ s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K); s[i]->s.k = 1; i++; /* X = A */ s[i] = new_stmt(cstate, BPF_MISC|BPF_TAX); i++; /* A = P[X + packet head] */ s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B); s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl; i++; /* A += 2 */ s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K); s[i]->s.k = 2; i++; /* A *= 4 */ s[i] = new_stmt(cstate, BPF_ALU|BPF_MUL|BPF_K); s[i]->s.k = 4; i++; /* X = A; */ s[i] = new_stmt(cstate, BPF_MISC|BPF_TAX); i++; /* A = MEM[reg2] */ s[i] = new_stmt(cstate, BPF_LD|BPF_MEM); s[i]->s.k = reg2; i++; /* goto again; (must use BPF_JA for backward jump) */ s[i] = new_stmt(cstate, BPF_JMP|BPF_JA); s[i]->s.k = again - i - 1; i++; /* end: nop */ end = i; s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K); s[i]->s.k = 0; s[fix2]->s.jt = s[end]; s[fix4]->s.jf = s[end]; s[fix5]->s.jt = s[end]; i++; /* * make slist chain */ max = i; for (i = 0; i < max - 1; i++) s[i]->next = s[i + 1]; s[max - 1]->next = NULL; /* * emit final check */ b = new_block(cstate, JMP(BPF_JEQ)); b->stmts = s[1]; /*remember, s[0] is dummy*/ b->s.k = v; free_reg(cstate, reg2); gen_and(b0, b); return b; } #endif /* !defined(NO_PROTOCHAIN) */ static struct block * gen_check_802_11_data_frame(compiler_state_t *cstate) { struct slist *s; struct block *b0, *b1; /* * A data frame has the 0x08 bit (b3) in the frame control field set * and the 0x04 bit (b2) clear. */ s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B); b0 = new_block(cstate, JMP(BPF_JSET)); b0->s.k = 0x08; b0->stmts = s; s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B); b1 = new_block(cstate, JMP(BPF_JSET)); b1->s.k = 0x04; b1->stmts = s; gen_not(b1); gen_and(b1, b0); return b0; } /* * Generate code that checks whether the packet is a packet for protocol * <proto> and whether the type field in that protocol's header has * the value <v>, e.g. if <proto> is Q_IP, it checks whether it's an * IP packet and checks the protocol number in the IP header against <v>. * * If <proto> is Q_DEFAULT, i.e. just "proto" was specified, it checks * against Q_IP and Q_IPV6. */ static struct block * gen_proto(compiler_state_t *cstate, bpf_u_int32 v, int proto, int dir) { struct block *b0, *b1; struct block *b2; if (dir != Q_DEFAULT) bpf_error(cstate, "direction applied to 'proto'"); switch (proto) { case Q_DEFAULT: b0 = gen_proto(cstate, v, Q_IP, dir); b1 = gen_proto(cstate, v, Q_IPV6, dir); gen_or(b0, b1); return b1; case Q_LINK: return gen_linktype(cstate, v); case Q_IP: /* * For FDDI, RFC 1188 says that SNAP encapsulation is used, * not LLC encapsulation with LLCSAP_IP. * * For IEEE 802 networks - which includes 802.5 token ring * (which is what DLT_IEEE802 means) and 802.11 - RFC 1042 * says that SNAP encapsulation is used, not LLC encapsulation * with LLCSAP_IP. * * For LLC-encapsulated ATM/"Classical IP", RFC 1483 and * RFC 2225 say that SNAP encapsulation is used, not LLC * encapsulation with LLCSAP_IP. * * So we always check for ETHERTYPE_IP. */ b0 = gen_linktype(cstate, ETHERTYPE_IP); b1 = gen_cmp(cstate, OR_LINKPL, 9, BPF_B, v); gen_and(b0, b1); return b1; case Q_ARP: bpf_error(cstate, "arp does not encapsulate another protocol"); /*NOTREACHED*/ case Q_RARP: bpf_error(cstate, "rarp does not encapsulate another protocol"); /*NOTREACHED*/ case Q_SCTP: bpf_error(cstate, "'sctp proto' is bogus"); /*NOTREACHED*/ case Q_TCP: bpf_error(cstate, "'tcp proto' is bogus"); /*NOTREACHED*/ case Q_UDP: bpf_error(cstate, "'udp proto' is bogus"); /*NOTREACHED*/ case Q_ICMP: bpf_error(cstate, "'icmp proto' is bogus"); /*NOTREACHED*/ case Q_IGMP: bpf_error(cstate, "'igmp proto' is bogus"); /*NOTREACHED*/ case Q_IGRP: bpf_error(cstate, "'igrp proto' is bogus"); /*NOTREACHED*/ case Q_ATALK: bpf_error(cstate, "AppleTalk encapsulation is not specifiable"); /*NOTREACHED*/ case Q_DECNET: bpf_error(cstate, "DECNET encapsulation is not specifiable"); /*NOTREACHED*/ case Q_LAT: bpf_error(cstate, "LAT does not encapsulate another protocol"); /*NOTREACHED*/ case Q_SCA: bpf_error(cstate, "SCA does not encapsulate another protocol"); /*NOTREACHED*/ case Q_MOPRC: bpf_error(cstate, "MOPRC does not encapsulate another protocol"); /*NOTREACHED*/ case Q_MOPDL: bpf_error(cstate, "MOPDL does not encapsulate another protocol"); /*NOTREACHED*/ case Q_IPV6: b0 = gen_linktype(cstate, ETHERTYPE_IPV6); /* * Also check for a fragment header before the final * header. */ b2 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, IPPROTO_FRAGMENT); b1 = gen_cmp(cstate, OR_LINKPL, 40, BPF_B, v); gen_and(b2, b1); b2 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, v); gen_or(b2, b1); gen_and(b0, b1); return b1; case Q_ICMPV6: bpf_error(cstate, "'icmp6 proto' is bogus"); /*NOTREACHED*/ case Q_AH: bpf_error(cstate, "'ah proto' is bogus"); /*NOTREACHED*/ case Q_ESP: bpf_error(cstate, "'esp proto' is bogus"); /*NOTREACHED*/ case Q_PIM: bpf_error(cstate, "'pim proto' is bogus"); /*NOTREACHED*/ case Q_VRRP: bpf_error(cstate, "'vrrp proto' is bogus"); /*NOTREACHED*/ case Q_AARP: bpf_error(cstate, "'aarp proto' is bogus"); /*NOTREACHED*/ case Q_ISO: switch (cstate->linktype) { case DLT_FRELAY: /* * Frame Relay packets typically have an OSI * NLPID at the beginning; "gen_linktype(cstate, LLCSAP_ISONS)" * generates code to check for all the OSI * NLPIDs, so calling it and then adding a check * for the particular NLPID for which we're * looking is bogus, as we can just check for * the NLPID. * * What we check for is the NLPID and a frame * control field value of UI, i.e. 0x03 followed * by the NLPID. * * XXX - assumes a 2-byte Frame Relay header with * DLCI and flags. What if the address is longer? * * XXX - what about SNAP-encapsulated frames? */ return gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | v); /*NOTREACHED*/ case DLT_C_HDLC: case DLT_HDLC: /* * Cisco uses an Ethertype lookalike - for OSI, * it's 0xfefe. */ b0 = gen_linktype(cstate, LLCSAP_ISONS<<8 | LLCSAP_ISONS); /* OSI in C-HDLC is stuffed with a fudge byte */ b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 1, BPF_B, v); gen_and(b0, b1); return b1; default: b0 = gen_linktype(cstate, LLCSAP_ISONS); b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 0, BPF_B, v); gen_and(b0, b1); return b1; } case Q_ESIS: bpf_error(cstate, "'esis proto' is bogus"); /*NOTREACHED*/ case Q_ISIS: b0 = gen_proto(cstate, ISO10589_ISIS, Q_ISO, Q_DEFAULT); /* * 4 is the offset of the PDU type relative to the IS-IS * header. */ b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 4, BPF_B, v); gen_and(b0, b1); return b1; case Q_CLNP: bpf_error(cstate, "'clnp proto' is not supported"); /*NOTREACHED*/ case Q_STP: bpf_error(cstate, "'stp proto' is bogus"); /*NOTREACHED*/ case Q_IPX: bpf_error(cstate, "'ipx proto' is bogus"); /*NOTREACHED*/ case Q_NETBEUI: bpf_error(cstate, "'netbeui proto' is bogus"); /*NOTREACHED*/ case Q_ISIS_L1: bpf_error(cstate, "'l1 proto' is bogus"); /*NOTREACHED*/ case Q_ISIS_L2: bpf_error(cstate, "'l2 proto' is bogus"); /*NOTREACHED*/ case Q_ISIS_IIH: bpf_error(cstate, "'iih proto' is bogus"); /*NOTREACHED*/ case Q_ISIS_SNP: bpf_error(cstate, "'snp proto' is bogus"); /*NOTREACHED*/ case Q_ISIS_CSNP: bpf_error(cstate, "'csnp proto' is bogus"); /*NOTREACHED*/ case Q_ISIS_PSNP: bpf_error(cstate, "'psnp proto' is bogus"); /*NOTREACHED*/ case Q_ISIS_LSP: bpf_error(cstate, "'lsp proto' is bogus"); /*NOTREACHED*/ case Q_RADIO: bpf_error(cstate, "'radio proto' is bogus"); /*NOTREACHED*/ case Q_CARP: bpf_error(cstate, "'carp proto' is bogus"); /*NOTREACHED*/ default: abort(); /*NOTREACHED*/ } /*NOTREACHED*/ } struct block * gen_scode(compiler_state_t *cstate, const char *name, struct qual q) { int proto = q.proto; int dir = q.dir; int tproto; u_char *eaddr; bpf_u_int32 mask, addr; struct addrinfo *res, *res0; struct sockaddr_in *sin4; #ifdef INET6 int tproto6; struct sockaddr_in6 *sin6; struct in6_addr mask128; #endif /*INET6*/ struct block *b, *tmp; int port, real_proto; int port1, port2; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); switch (q.addr) { case Q_NET: addr = pcap_nametonetaddr(name); if (addr == 0) bpf_error(cstate, "unknown network '%s'", name); /* Left justify network addr and calculate its network mask */ mask = 0xffffffff; while (addr && (addr & 0xff000000) == 0) { addr <<= 8; mask <<= 8; } return gen_host(cstate, addr, mask, proto, dir, q.addr); case Q_DEFAULT: case Q_HOST: if (proto == Q_LINK) { switch (cstate->linktype) { case DLT_EN10MB: case DLT_NETANALYZER: case DLT_NETANALYZER_TRANSPARENT: eaddr = pcap_ether_hostton(name); if (eaddr == NULL) bpf_error(cstate, "unknown ether host '%s'", name); tmp = gen_prevlinkhdr_check(cstate); b = gen_ehostop(cstate, eaddr, dir); if (tmp != NULL) gen_and(tmp, b); free(eaddr); return b; case DLT_FDDI: eaddr = pcap_ether_hostton(name); if (eaddr == NULL) bpf_error(cstate, "unknown FDDI host '%s'", name); b = gen_fhostop(cstate, eaddr, dir); free(eaddr); return b; case DLT_IEEE802: eaddr = pcap_ether_hostton(name); if (eaddr == NULL) bpf_error(cstate, "unknown token ring host '%s'", name); b = gen_thostop(cstate, eaddr, dir); free(eaddr); return b; case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO_AVS: case DLT_IEEE802_11_RADIO: case DLT_PPI: eaddr = pcap_ether_hostton(name); if (eaddr == NULL) bpf_error(cstate, "unknown 802.11 host '%s'", name); b = gen_wlanhostop(cstate, eaddr, dir); free(eaddr); return b; case DLT_IP_OVER_FC: eaddr = pcap_ether_hostton(name); if (eaddr == NULL) bpf_error(cstate, "unknown Fibre Channel host '%s'", name); b = gen_ipfchostop(cstate, eaddr, dir); free(eaddr); return b; } bpf_error(cstate, "only ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel supports link-level host name"); } else if (proto == Q_DECNET) { unsigned short dn_addr; if (!__pcap_nametodnaddr(name, &dn_addr)) { #ifdef DECNETLIB bpf_error(cstate, "unknown decnet host name '%s'\n", name); #else bpf_error(cstate, "decnet name support not included, '%s' cannot be translated\n", name); #endif } /* * I don't think DECNET hosts can be multihomed, so * there is no need to build up a list of addresses */ return (gen_host(cstate, dn_addr, 0, proto, dir, q.addr)); } else { #ifdef INET6 memset(&mask128, 0xff, sizeof(mask128)); #endif res0 = res = pcap_nametoaddrinfo(name); if (res == NULL) bpf_error(cstate, "unknown host '%s'", name); cstate->ai = res; b = tmp = NULL; tproto = proto; #ifdef INET6 tproto6 = proto; #endif if (cstate->off_linktype.constant_part == OFFSET_NOT_SET && tproto == Q_DEFAULT) { tproto = Q_IP; #ifdef INET6 tproto6 = Q_IPV6; #endif } for (res = res0; res; res = res->ai_next) { switch (res->ai_family) { case AF_INET: #ifdef INET6 if (tproto == Q_IPV6) continue; #endif sin4 = (struct sockaddr_in *) res->ai_addr; tmp = gen_host(cstate, ntohl(sin4->sin_addr.s_addr), 0xffffffff, tproto, dir, q.addr); break; #ifdef INET6 case AF_INET6: if (tproto6 == Q_IP) continue; sin6 = (struct sockaddr_in6 *) res->ai_addr; tmp = gen_host6(cstate, &sin6->sin6_addr, &mask128, tproto6, dir, q.addr); break; #endif default: continue; } if (b) gen_or(b, tmp); b = tmp; } cstate->ai = NULL; freeaddrinfo(res0); if (b == NULL) { bpf_error(cstate, "unknown host '%s'%s", name, (proto == Q_DEFAULT) ? "" : " for specified address family"); } return b; } case Q_PORT: if (proto != Q_DEFAULT && proto != Q_UDP && proto != Q_TCP && proto != Q_SCTP) bpf_error(cstate, "illegal qualifier of 'port'"); if (pcap_nametoport(name, &port, &real_proto) == 0) bpf_error(cstate, "unknown port '%s'", name); if (proto == Q_UDP) { if (real_proto == IPPROTO_TCP) bpf_error(cstate, "port '%s' is tcp", name); else if (real_proto == IPPROTO_SCTP) bpf_error(cstate, "port '%s' is sctp", name); else /* override PROTO_UNDEF */ real_proto = IPPROTO_UDP; } if (proto == Q_TCP) { if (real_proto == IPPROTO_UDP) bpf_error(cstate, "port '%s' is udp", name); else if (real_proto == IPPROTO_SCTP) bpf_error(cstate, "port '%s' is sctp", name); else /* override PROTO_UNDEF */ real_proto = IPPROTO_TCP; } if (proto == Q_SCTP) { if (real_proto == IPPROTO_UDP) bpf_error(cstate, "port '%s' is udp", name); else if (real_proto == IPPROTO_TCP) bpf_error(cstate, "port '%s' is tcp", name); else /* override PROTO_UNDEF */ real_proto = IPPROTO_SCTP; } if (port < 0) bpf_error(cstate, "illegal port number %d < 0", port); if (port > 65535) bpf_error(cstate, "illegal port number %d > 65535", port); b = gen_port(cstate, port, real_proto, dir); gen_or(gen_port6(cstate, port, real_proto, dir), b); return b; case Q_PORTRANGE: if (proto != Q_DEFAULT && proto != Q_UDP && proto != Q_TCP && proto != Q_SCTP) bpf_error(cstate, "illegal qualifier of 'portrange'"); if (pcap_nametoportrange(name, &port1, &port2, &real_proto) == 0) bpf_error(cstate, "unknown port in range '%s'", name); if (proto == Q_UDP) { if (real_proto == IPPROTO_TCP) bpf_error(cstate, "port in range '%s' is tcp", name); else if (real_proto == IPPROTO_SCTP) bpf_error(cstate, "port in range '%s' is sctp", name); else /* override PROTO_UNDEF */ real_proto = IPPROTO_UDP; } if (proto == Q_TCP) { if (real_proto == IPPROTO_UDP) bpf_error(cstate, "port in range '%s' is udp", name); else if (real_proto == IPPROTO_SCTP) bpf_error(cstate, "port in range '%s' is sctp", name); else /* override PROTO_UNDEF */ real_proto = IPPROTO_TCP; } if (proto == Q_SCTP) { if (real_proto == IPPROTO_UDP) bpf_error(cstate, "port in range '%s' is udp", name); else if (real_proto == IPPROTO_TCP) bpf_error(cstate, "port in range '%s' is tcp", name); else /* override PROTO_UNDEF */ real_proto = IPPROTO_SCTP; } if (port1 < 0) bpf_error(cstate, "illegal port number %d < 0", port1); if (port1 > 65535) bpf_error(cstate, "illegal port number %d > 65535", port1); if (port2 < 0) bpf_error(cstate, "illegal port number %d < 0", port2); if (port2 > 65535) bpf_error(cstate, "illegal port number %d > 65535", port2); b = gen_portrange(cstate, port1, port2, real_proto, dir); gen_or(gen_portrange6(cstate, port1, port2, real_proto, dir), b); return b; case Q_GATEWAY: #ifndef INET6 eaddr = pcap_ether_hostton(name); if (eaddr == NULL) bpf_error(cstate, "unknown ether host: %s", name); res = pcap_nametoaddrinfo(name); cstate->ai = res; if (res == NULL) bpf_error(cstate, "unknown host '%s'", name); b = gen_gateway(cstate, eaddr, res, proto, dir); cstate->ai = NULL; freeaddrinfo(res); if (b == NULL) bpf_error(cstate, "unknown host '%s'", name); return b; #else bpf_error(cstate, "'gateway' not supported in this configuration"); #endif /*INET6*/ case Q_PROTO: real_proto = lookup_proto(cstate, name, proto); if (real_proto >= 0) return gen_proto(cstate, real_proto, proto, dir); else bpf_error(cstate, "unknown protocol: %s", name); #if !defined(NO_PROTOCHAIN) case Q_PROTOCHAIN: real_proto = lookup_proto(cstate, name, proto); if (real_proto >= 0) return gen_protochain(cstate, real_proto, proto); else bpf_error(cstate, "unknown protocol: %s", name); #endif /* !defined(NO_PROTOCHAIN) */ case Q_UNDEF: syntax(cstate); /*NOTREACHED*/ } abort(); /*NOTREACHED*/ } struct block * gen_mcode(compiler_state_t *cstate, const char *s1, const char *s2, bpf_u_int32 masklen, struct qual q) { register int nlen, mlen; bpf_u_int32 n, m; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); nlen = __pcap_atoin(s1, &n); if (nlen < 0) bpf_error(cstate, "invalid IPv4 address '%s'", s1); /* Promote short ipaddr */ n <<= 32 - nlen; if (s2 != NULL) { mlen = __pcap_atoin(s2, &m); if (mlen < 0) bpf_error(cstate, "invalid IPv4 address '%s'", s2); /* Promote short ipaddr */ m <<= 32 - mlen; if ((n & ~m) != 0) bpf_error(cstate, "non-network bits set in \"%s mask %s\"", s1, s2); } else { /* Convert mask len to mask */ if (masklen > 32) bpf_error(cstate, "mask length must be <= 32"); if (masklen == 0) { /* * X << 32 is not guaranteed by C to be 0; it's * undefined. */ m = 0; } else m = 0xffffffff << (32 - masklen); if ((n & ~m) != 0) bpf_error(cstate, "non-network bits set in \"%s/%d\"", s1, masklen); } switch (q.addr) { case Q_NET: return gen_host(cstate, n, m, q.proto, q.dir, q.addr); default: bpf_error(cstate, "Mask syntax for networks only"); /*NOTREACHED*/ } /*NOTREACHED*/ } struct block * gen_ncode(compiler_state_t *cstate, const char *s, bpf_u_int32 v, struct qual q) { bpf_u_int32 mask; int proto; int dir; register int vlen; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); proto = q.proto; dir = q.dir; if (s == NULL) vlen = 32; else if (q.proto == Q_DECNET) { vlen = __pcap_atodn(s, &v); if (vlen == 0) bpf_error(cstate, "malformed decnet address '%s'", s); } else { vlen = __pcap_atoin(s, &v); if (vlen < 0) bpf_error(cstate, "invalid IPv4 address '%s'", s); } switch (q.addr) { case Q_DEFAULT: case Q_HOST: case Q_NET: if (proto == Q_DECNET) return gen_host(cstate, v, 0, proto, dir, q.addr); else if (proto == Q_LINK) { bpf_error(cstate, "illegal link layer address"); } else { mask = 0xffffffff; if (s == NULL && q.addr == Q_NET) { /* Promote short net number */ while (v && (v & 0xff000000) == 0) { v <<= 8; mask <<= 8; } } else { /* Promote short ipaddr */ v <<= 32 - vlen; mask <<= 32 - vlen ; } return gen_host(cstate, v, mask, proto, dir, q.addr); } case Q_PORT: if (proto == Q_UDP) proto = IPPROTO_UDP; else if (proto == Q_TCP) proto = IPPROTO_TCP; else if (proto == Q_SCTP) proto = IPPROTO_SCTP; else if (proto == Q_DEFAULT) proto = PROTO_UNDEF; else bpf_error(cstate, "illegal qualifier of 'port'"); if (v > 65535) bpf_error(cstate, "illegal port number %u > 65535", v); { struct block *b; b = gen_port(cstate, v, proto, dir); gen_or(gen_port6(cstate, v, proto, dir), b); return b; } case Q_PORTRANGE: if (proto == Q_UDP) proto = IPPROTO_UDP; else if (proto == Q_TCP) proto = IPPROTO_TCP; else if (proto == Q_SCTP) proto = IPPROTO_SCTP; else if (proto == Q_DEFAULT) proto = PROTO_UNDEF; else bpf_error(cstate, "illegal qualifier of 'portrange'"); if (v > 65535) bpf_error(cstate, "illegal port number %u > 65535", v); { struct block *b; b = gen_portrange(cstate, v, v, proto, dir); gen_or(gen_portrange6(cstate, v, v, proto, dir), b); return b; } case Q_GATEWAY: bpf_error(cstate, "'gateway' requires a name"); /*NOTREACHED*/ case Q_PROTO: return gen_proto(cstate, v, proto, dir); #if !defined(NO_PROTOCHAIN) case Q_PROTOCHAIN: return gen_protochain(cstate, v, proto); #endif case Q_UNDEF: syntax(cstate); /*NOTREACHED*/ default: abort(); /*NOTREACHED*/ } /*NOTREACHED*/ } #ifdef INET6 struct block * gen_mcode6(compiler_state_t *cstate, const char *s1, const char *s2, bpf_u_int32 masklen, struct qual q) { struct addrinfo *res; struct in6_addr *addr; struct in6_addr mask; struct block *b; uint32_t *a, *m; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); if (s2) bpf_error(cstate, "no mask %s supported", s2); res = pcap_nametoaddrinfo(s1); if (!res) bpf_error(cstate, "invalid ip6 address %s", s1); cstate->ai = res; if (res->ai_next) bpf_error(cstate, "%s resolved to multiple address", s1); addr = &((struct sockaddr_in6 *)res->ai_addr)->sin6_addr; if (masklen > sizeof(mask.s6_addr) * 8) bpf_error(cstate, "mask length must be <= %u", (unsigned int)(sizeof(mask.s6_addr) * 8)); memset(&mask, 0, sizeof(mask)); memset(&mask.s6_addr, 0xff, masklen / 8); if (masklen % 8) { mask.s6_addr[masklen / 8] = (0xff << (8 - masklen % 8)) & 0xff; } a = (uint32_t *)addr; m = (uint32_t *)&mask; if ((a[0] & ~m[0]) || (a[1] & ~m[1]) || (a[2] & ~m[2]) || (a[3] & ~m[3])) { bpf_error(cstate, "non-network bits set in \"%s/%d\"", s1, masklen); } switch (q.addr) { case Q_DEFAULT: case Q_HOST: if (masklen != 128) bpf_error(cstate, "Mask syntax for networks only"); /* FALLTHROUGH */ case Q_NET: b = gen_host6(cstate, addr, &mask, q.proto, q.dir, q.addr); cstate->ai = NULL; freeaddrinfo(res); return b; default: bpf_error(cstate, "invalid qualifier against IPv6 address"); /*NOTREACHED*/ } } #endif /*INET6*/ struct block * gen_ecode(compiler_state_t *cstate, const char *s, struct qual q) { struct block *b, *tmp; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) && q.proto == Q_LINK) { cstate->e = pcap_ether_aton(s); if (cstate->e == NULL) bpf_error(cstate, "malloc"); switch (cstate->linktype) { case DLT_EN10MB: case DLT_NETANALYZER: case DLT_NETANALYZER_TRANSPARENT: tmp = gen_prevlinkhdr_check(cstate); b = gen_ehostop(cstate, cstate->e, (int)q.dir); if (tmp != NULL) gen_and(tmp, b); break; case DLT_FDDI: b = gen_fhostop(cstate, cstate->e, (int)q.dir); break; case DLT_IEEE802: b = gen_thostop(cstate, cstate->e, (int)q.dir); break; case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO_AVS: case DLT_IEEE802_11_RADIO: case DLT_PPI: b = gen_wlanhostop(cstate, cstate->e, (int)q.dir); break; case DLT_IP_OVER_FC: b = gen_ipfchostop(cstate, cstate->e, (int)q.dir); break; default: free(cstate->e); cstate->e = NULL; bpf_error(cstate, "ethernet addresses supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel"); /*NOTREACHED*/ } free(cstate->e); cstate->e = NULL; return (b); } bpf_error(cstate, "ethernet address used in non-ether expression"); /*NOTREACHED*/ } void sappend(struct slist *s0, struct slist *s1) { /* * This is definitely not the best way to do this, but the * lists will rarely get long. */ while (s0->next) s0 = s0->next; s0->next = s1; } static struct slist * xfer_to_x(compiler_state_t *cstate, struct arth *a) { struct slist *s; s = new_stmt(cstate, BPF_LDX|BPF_MEM); s->s.k = a->regno; return s; } static struct slist * xfer_to_a(compiler_state_t *cstate, struct arth *a) { struct slist *s; s = new_stmt(cstate, BPF_LD|BPF_MEM); s->s.k = a->regno; return s; } /* * Modify "index" to use the value stored into its register as an * offset relative to the beginning of the header for the protocol * "proto", and allocate a register and put an item "size" bytes long * (1, 2, or 4) at that offset into that register, making it the register * for "index". */ static struct arth * gen_load_internal(compiler_state_t *cstate, int proto, struct arth *inst, bpf_u_int32 size) { int size_code; struct slist *s, *tmp; struct block *b; int regno = alloc_reg(cstate); free_reg(cstate, inst->regno); switch (size) { default: bpf_error(cstate, "data size must be 1, 2, or 4"); /*NOTREACHED*/ case 1: size_code = BPF_B; break; case 2: size_code = BPF_H; break; case 4: size_code = BPF_W; break; } switch (proto) { default: bpf_error(cstate, "unsupported index operation"); case Q_RADIO: /* * The offset is relative to the beginning of the packet * data, if we have a radio header. (If we don't, this * is an error.) */ if (cstate->linktype != DLT_IEEE802_11_RADIO_AVS && cstate->linktype != DLT_IEEE802_11_RADIO && cstate->linktype != DLT_PRISM_HEADER) bpf_error(cstate, "radio information not present in capture"); /* * Load into the X register the offset computed into the * register specified by "index". */ s = xfer_to_x(cstate, inst); /* * Load the item at that offset. */ tmp = new_stmt(cstate, BPF_LD|BPF_IND|size_code); sappend(s, tmp); sappend(inst->s, s); break; case Q_LINK: /* * The offset is relative to the beginning of * the link-layer header. * * XXX - what about ATM LANE? Should the index be * relative to the beginning of the AAL5 frame, so * that 0 refers to the beginning of the LE Control * field, or relative to the beginning of the LAN * frame, so that 0 refers, for Ethernet LANE, to * the beginning of the destination address? */ s = gen_abs_offset_varpart(cstate, &cstate->off_linkhdr); /* * If "s" is non-null, it has code to arrange that the * X register contains the length of the prefix preceding * the link-layer header. Add to it the offset computed * into the register specified by "index", and move that * into the X register. Otherwise, just load into the X * register the offset computed into the register specified * by "index". */ if (s != NULL) { sappend(s, xfer_to_a(cstate, inst)); sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X)); sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX)); } else s = xfer_to_x(cstate, inst); /* * Load the item at the sum of the offset we've put in the * X register and the offset of the start of the link * layer header (which is 0 if the radio header is * variable-length; that header length is what we put * into the X register and then added to the index). */ tmp = new_stmt(cstate, BPF_LD|BPF_IND|size_code); tmp->s.k = cstate->off_linkhdr.constant_part; sappend(s, tmp); sappend(inst->s, s); break; case Q_IP: case Q_ARP: case Q_RARP: case Q_ATALK: case Q_DECNET: case Q_SCA: case Q_LAT: case Q_MOPRC: case Q_MOPDL: case Q_IPV6: /* * The offset is relative to the beginning of * the network-layer header. * XXX - are there any cases where we want * cstate->off_nl_nosnap? */ s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl); /* * If "s" is non-null, it has code to arrange that the * X register contains the variable part of the offset * of the link-layer payload. Add to it the offset * computed into the register specified by "index", * and move that into the X register. Otherwise, just * load into the X register the offset computed into * the register specified by "index". */ if (s != NULL) { sappend(s, xfer_to_a(cstate, inst)); sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X)); sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX)); } else s = xfer_to_x(cstate, inst); /* * Load the item at the sum of the offset we've put in the * X register, the offset of the start of the network * layer header from the beginning of the link-layer * payload, and the constant part of the offset of the * start of the link-layer payload. */ tmp = new_stmt(cstate, BPF_LD|BPF_IND|size_code); tmp->s.k = cstate->off_linkpl.constant_part + cstate->off_nl; sappend(s, tmp); sappend(inst->s, s); /* * Do the computation only if the packet contains * the protocol in question. */ b = gen_proto_abbrev_internal(cstate, proto); if (inst->b) gen_and(inst->b, b); inst->b = b; break; case Q_SCTP: case Q_TCP: case Q_UDP: case Q_ICMP: case Q_IGMP: case Q_IGRP: case Q_PIM: case Q_VRRP: case Q_CARP: /* * The offset is relative to the beginning of * the transport-layer header. * * Load the X register with the length of the IPv4 header * (plus the offset of the link-layer header, if it's * a variable-length header), in bytes. * * XXX - are there any cases where we want * cstate->off_nl_nosnap? * XXX - we should, if we're built with * IPv6 support, generate code to load either * IPv4, IPv6, or both, as appropriate. */ s = gen_loadx_iphdrlen(cstate); /* * The X register now contains the sum of the variable * part of the offset of the link-layer payload and the * length of the network-layer header. * * Load into the A register the offset relative to * the beginning of the transport layer header, * add the X register to that, move that to the * X register, and load with an offset from the * X register equal to the sum of the constant part of * the offset of the link-layer payload and the offset, * relative to the beginning of the link-layer payload, * of the network-layer header. */ sappend(s, xfer_to_a(cstate, inst)); sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X)); sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX)); sappend(s, tmp = new_stmt(cstate, BPF_LD|BPF_IND|size_code)); tmp->s.k = cstate->off_linkpl.constant_part + cstate->off_nl; sappend(inst->s, s); /* * Do the computation only if the packet contains * the protocol in question - which is true only * if this is an IP datagram and is the first or * only fragment of that datagram. */ gen_and(gen_proto_abbrev_internal(cstate, proto), b = gen_ipfrag(cstate)); if (inst->b) gen_and(inst->b, b); gen_and(gen_proto_abbrev_internal(cstate, Q_IP), b); inst->b = b; break; case Q_ICMPV6: /* * Do the computation only if the packet contains * the protocol in question. */ b = gen_proto_abbrev_internal(cstate, Q_IPV6); if (inst->b) { gen_and(inst->b, b); } inst->b = b; /* * Check if we have an icmp6 next header */ b = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, 58); if (inst->b) { gen_and(inst->b, b); } inst->b = b; s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl); /* * If "s" is non-null, it has code to arrange that the * X register contains the variable part of the offset * of the link-layer payload. Add to it the offset * computed into the register specified by "index", * and move that into the X register. Otherwise, just * load into the X register the offset computed into * the register specified by "index". */ if (s != NULL) { sappend(s, xfer_to_a(cstate, inst)); sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X)); sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX)); } else { s = xfer_to_x(cstate, inst); } /* * Load the item at the sum of the offset we've put in the * X register, the offset of the start of the network * layer header from the beginning of the link-layer * payload, and the constant part of the offset of the * start of the link-layer payload. */ tmp = new_stmt(cstate, BPF_LD|BPF_IND|size_code); tmp->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 40; sappend(s, tmp); sappend(inst->s, s); break; } inst->regno = regno; s = new_stmt(cstate, BPF_ST); s->s.k = regno; sappend(inst->s, s); return inst; } struct arth * gen_load(compiler_state_t *cstate, int proto, struct arth *inst, bpf_u_int32 size) { /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); return gen_load_internal(cstate, proto, inst, size); } static struct block * gen_relation_internal(compiler_state_t *cstate, int code, struct arth *a0, struct arth *a1, int reversed) { struct slist *s0, *s1, *s2; struct block *b, *tmp; s0 = xfer_to_x(cstate, a1); s1 = xfer_to_a(cstate, a0); if (code == BPF_JEQ) { s2 = new_stmt(cstate, BPF_ALU|BPF_SUB|BPF_X); b = new_block(cstate, JMP(code)); sappend(s1, s2); } else b = new_block(cstate, BPF_JMP|code|BPF_X); if (reversed) gen_not(b); sappend(s0, s1); sappend(a1->s, s0); sappend(a0->s, a1->s); b->stmts = a0->s; free_reg(cstate, a0->regno); free_reg(cstate, a1->regno); /* 'and' together protocol checks */ if (a0->b) { if (a1->b) { gen_and(a0->b, tmp = a1->b); } else tmp = a0->b; } else tmp = a1->b; if (tmp) gen_and(tmp, b); return b; } struct block * gen_relation(compiler_state_t *cstate, int code, struct arth *a0, struct arth *a1, int reversed) { /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); return gen_relation_internal(cstate, code, a0, a1, reversed); } struct arth * gen_loadlen(compiler_state_t *cstate) { int regno; struct arth *a; struct slist *s; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); regno = alloc_reg(cstate); a = (struct arth *)newchunk(cstate, sizeof(*a)); s = new_stmt(cstate, BPF_LD|BPF_LEN); s->next = new_stmt(cstate, BPF_ST); s->next->s.k = regno; a->s = s; a->regno = regno; return a; } static struct arth * gen_loadi_internal(compiler_state_t *cstate, bpf_u_int32 val) { struct arth *a; struct slist *s; int reg; a = (struct arth *)newchunk(cstate, sizeof(*a)); reg = alloc_reg(cstate); s = new_stmt(cstate, BPF_LD|BPF_IMM); s->s.k = val; s->next = new_stmt(cstate, BPF_ST); s->next->s.k = reg; a->s = s; a->regno = reg; return a; } struct arth * gen_loadi(compiler_state_t *cstate, bpf_u_int32 val) { /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); return gen_loadi_internal(cstate, val); } /* * The a_arg dance is to avoid annoying whining by compilers that * a might be clobbered by longjmp - yeah, it might, but *WHO CARES*? * It's not *used* after setjmp returns. */ struct arth * gen_neg(compiler_state_t *cstate, struct arth *a_arg) { struct arth *a = a_arg; struct slist *s; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); s = xfer_to_a(cstate, a); sappend(a->s, s); s = new_stmt(cstate, BPF_ALU|BPF_NEG); s->s.k = 0; sappend(a->s, s); s = new_stmt(cstate, BPF_ST); s->s.k = a->regno; sappend(a->s, s); return a; } /* * The a0_arg dance is to avoid annoying whining by compilers that * a0 might be clobbered by longjmp - yeah, it might, but *WHO CARES*? * It's not *used* after setjmp returns. */ struct arth * gen_arth(compiler_state_t *cstate, int code, struct arth *a0_arg, struct arth *a1) { struct arth *a0 = a0_arg; struct slist *s0, *s1, *s2; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); /* * Disallow division by, or modulus by, zero; we do this here * so that it gets done even if the optimizer is disabled. * * Also disallow shifts by a value greater than 31; we do this * here, for the same reason. */ if (code == BPF_DIV) { if (a1->s->s.code == (BPF_LD|BPF_IMM) && a1->s->s.k == 0) bpf_error(cstate, "division by zero"); } else if (code == BPF_MOD) { if (a1->s->s.code == (BPF_LD|BPF_IMM) && a1->s->s.k == 0) bpf_error(cstate, "modulus by zero"); } else if (code == BPF_LSH || code == BPF_RSH) { if (a1->s->s.code == (BPF_LD|BPF_IMM) && a1->s->s.k > 31) bpf_error(cstate, "shift by more than 31 bits"); } s0 = xfer_to_x(cstate, a1); s1 = xfer_to_a(cstate, a0); s2 = new_stmt(cstate, BPF_ALU|BPF_X|code); sappend(s1, s2); sappend(s0, s1); sappend(a1->s, s0); sappend(a0->s, a1->s); free_reg(cstate, a0->regno); free_reg(cstate, a1->regno); s0 = new_stmt(cstate, BPF_ST); a0->regno = s0->s.k = alloc_reg(cstate); sappend(a0->s, s0); return a0; } /* * Initialize the table of used registers and the current register. */ static void init_regs(compiler_state_t *cstate) { cstate->curreg = 0; memset(cstate->regused, 0, sizeof cstate->regused); } /* * Return the next free register. */ static int alloc_reg(compiler_state_t *cstate) { int n = BPF_MEMWORDS; while (--n >= 0) { if (cstate->regused[cstate->curreg]) cstate->curreg = (cstate->curreg + 1) % BPF_MEMWORDS; else { cstate->regused[cstate->curreg] = 1; return cstate->curreg; } } bpf_error(cstate, "too many registers needed to evaluate expression"); /*NOTREACHED*/ } /* * Return a register to the table so it can * be used later. */ static void free_reg(compiler_state_t *cstate, int n) { cstate->regused[n] = 0; } static struct block * gen_len(compiler_state_t *cstate, int jmp, int n) { struct slist *s; struct block *b; s = new_stmt(cstate, BPF_LD|BPF_LEN); b = new_block(cstate, JMP(jmp)); b->stmts = s; b->s.k = n; return b; } struct block * gen_greater(compiler_state_t *cstate, int n) { /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); return gen_len(cstate, BPF_JGE, n); } /* * Actually, this is less than or equal. */ struct block * gen_less(compiler_state_t *cstate, int n) { struct block *b; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); b = gen_len(cstate, BPF_JGT, n); gen_not(b); return b; } /* * This is for "byte {idx} {op} {val}"; "idx" is treated as relative to * the beginning of the link-layer header. * XXX - that means you can't test values in the radiotap header, but * as that header is difficult if not impossible to parse generally * without a loop, that might not be a severe problem. A new keyword * "radio" could be added for that, although what you'd really want * would be a way of testing particular radio header values, which * would generate code appropriate to the radio header in question. */ struct block * gen_byteop(compiler_state_t *cstate, int op, int idx, bpf_u_int32 val) { struct block *b; struct slist *s; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); switch (op) { default: abort(); case '=': return gen_cmp(cstate, OR_LINKHDR, (u_int)idx, BPF_B, val); case '<': b = gen_cmp_lt(cstate, OR_LINKHDR, (u_int)idx, BPF_B, val); return b; case '>': b = gen_cmp_gt(cstate, OR_LINKHDR, (u_int)idx, BPF_B, val); return b; case '|': s = new_stmt(cstate, BPF_ALU|BPF_OR|BPF_K); break; case '&': s = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K); break; } s->s.k = val; b = new_block(cstate, JMP(BPF_JEQ)); b->stmts = s; gen_not(b); return b; } static const u_char abroadcast[] = { 0x0 }; struct block * gen_broadcast(compiler_state_t *cstate, int proto) { bpf_u_int32 hostmask; struct block *b0, *b1, *b2; static const u_char ebroadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); switch (proto) { case Q_DEFAULT: case Q_LINK: switch (cstate->linktype) { case DLT_ARCNET: case DLT_ARCNET_LINUX: return gen_ahostop(cstate, abroadcast, Q_DST); case DLT_EN10MB: case DLT_NETANALYZER: case DLT_NETANALYZER_TRANSPARENT: b1 = gen_prevlinkhdr_check(cstate); b0 = gen_ehostop(cstate, ebroadcast, Q_DST); if (b1 != NULL) gen_and(b1, b0); return b0; case DLT_FDDI: return gen_fhostop(cstate, ebroadcast, Q_DST); case DLT_IEEE802: return gen_thostop(cstate, ebroadcast, Q_DST); case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO_AVS: case DLT_IEEE802_11_RADIO: case DLT_PPI: return gen_wlanhostop(cstate, ebroadcast, Q_DST); case DLT_IP_OVER_FC: return gen_ipfchostop(cstate, ebroadcast, Q_DST); default: bpf_error(cstate, "not a broadcast link"); } /*NOTREACHED*/ case Q_IP: /* * We treat a netmask of PCAP_NETMASK_UNKNOWN (0xffffffff) * as an indication that we don't know the netmask, and fail * in that case. */ if (cstate->netmask == PCAP_NETMASK_UNKNOWN) bpf_error(cstate, "netmask not known, so 'ip broadcast' not supported"); b0 = gen_linktype(cstate, ETHERTYPE_IP); hostmask = ~cstate->netmask; b1 = gen_mcmp(cstate, OR_LINKPL, 16, BPF_W, 0, hostmask); b2 = gen_mcmp(cstate, OR_LINKPL, 16, BPF_W, ~0 & hostmask, hostmask); gen_or(b1, b2); gen_and(b0, b2); return b2; } bpf_error(cstate, "only link-layer/IP broadcast filters supported"); /*NOTREACHED*/ } /* * Generate code to test the low-order bit of a MAC address (that's * the bottom bit of the *first* byte). */ static struct block * gen_mac_multicast(compiler_state_t *cstate, int offset) { register struct block *b0; register struct slist *s; /* link[offset] & 1 != 0 */ s = gen_load_a(cstate, OR_LINKHDR, offset, BPF_B); b0 = new_block(cstate, JMP(BPF_JSET)); b0->s.k = 1; b0->stmts = s; return b0; } struct block * gen_multicast(compiler_state_t *cstate, int proto) { register struct block *b0, *b1, *b2; register struct slist *s; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); switch (proto) { case Q_DEFAULT: case Q_LINK: switch (cstate->linktype) { case DLT_ARCNET: case DLT_ARCNET_LINUX: /* all ARCnet multicasts use the same address */ return gen_ahostop(cstate, abroadcast, Q_DST); case DLT_EN10MB: case DLT_NETANALYZER: case DLT_NETANALYZER_TRANSPARENT: b1 = gen_prevlinkhdr_check(cstate); /* ether[0] & 1 != 0 */ b0 = gen_mac_multicast(cstate, 0); if (b1 != NULL) gen_and(b1, b0); return b0; case DLT_FDDI: /* * XXX TEST THIS: MIGHT NOT PORT PROPERLY XXX * * XXX - was that referring to bit-order issues? */ /* fddi[1] & 1 != 0 */ return gen_mac_multicast(cstate, 1); case DLT_IEEE802: /* tr[2] & 1 != 0 */ return gen_mac_multicast(cstate, 2); case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO_AVS: case DLT_IEEE802_11_RADIO: case DLT_PPI: /* * Oh, yuk. * * For control frames, there is no DA. * * For management frames, DA is at an * offset of 4 from the beginning of * the packet. * * For data frames, DA is at an offset * of 4 from the beginning of the packet * if To DS is clear and at an offset of * 16 from the beginning of the packet * if To DS is set. */ /* * Generate the tests to be done for data frames. * * First, check for To DS set, i.e. "link[1] & 0x01". */ s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B); b1 = new_block(cstate, JMP(BPF_JSET)); b1->s.k = 0x01; /* To DS */ b1->stmts = s; /* * If To DS is set, the DA is at 16. */ b0 = gen_mac_multicast(cstate, 16); gen_and(b1, b0); /* * Now, check for To DS not set, i.e. check * "!(link[1] & 0x01)". */ s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B); b2 = new_block(cstate, JMP(BPF_JSET)); b2->s.k = 0x01; /* To DS */ b2->stmts = s; gen_not(b2); /* * If To DS is not set, the DA is at 4. */ b1 = gen_mac_multicast(cstate, 4); gen_and(b2, b1); /* * Now OR together the last two checks. That gives * the complete set of checks for data frames. */ gen_or(b1, b0); /* * Now check for a data frame. * I.e, check "link[0] & 0x08". */ s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B); b1 = new_block(cstate, JMP(BPF_JSET)); b1->s.k = 0x08; b1->stmts = s; /* * AND that with the checks done for data frames. */ gen_and(b1, b0); /* * If the high-order bit of the type value is 0, this * is a management frame. * I.e, check "!(link[0] & 0x08)". */ s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B); b2 = new_block(cstate, JMP(BPF_JSET)); b2->s.k = 0x08; b2->stmts = s; gen_not(b2); /* * For management frames, the DA is at 4. */ b1 = gen_mac_multicast(cstate, 4); gen_and(b2, b1); /* * OR that with the checks done for data frames. * That gives the checks done for management and * data frames. */ gen_or(b1, b0); /* * If the low-order bit of the type value is 1, * this is either a control frame or a frame * with a reserved type, and thus not a * frame with an SA. * * I.e., check "!(link[0] & 0x04)". */ s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B); b1 = new_block(cstate, JMP(BPF_JSET)); b1->s.k = 0x04; b1->stmts = s; gen_not(b1); /* * AND that with the checks for data and management * frames. */ gen_and(b1, b0); return b0; case DLT_IP_OVER_FC: b0 = gen_mac_multicast(cstate, 2); return b0; default: break; } /* Link not known to support multicasts */ break; case Q_IP: b0 = gen_linktype(cstate, ETHERTYPE_IP); b1 = gen_cmp_ge(cstate, OR_LINKPL, 16, BPF_B, 224); gen_and(b0, b1); return b1; case Q_IPV6: b0 = gen_linktype(cstate, ETHERTYPE_IPV6); b1 = gen_cmp(cstate, OR_LINKPL, 24, BPF_B, 255); gen_and(b0, b1); return b1; } bpf_error(cstate, "link-layer multicast filters supported only on ethernet/FDDI/token ring/ARCNET/802.11/ATM LANE/Fibre Channel"); /*NOTREACHED*/ } struct block * gen_ifindex(compiler_state_t *cstate, int ifindex) { register struct block *b0; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); /* * Only some data link types support ifindex qualifiers. */ switch (cstate->linktype) { case DLT_LINUX_SLL2: /* match packets on this interface */ b0 = gen_cmp(cstate, OR_LINKHDR, 4, BPF_W, ifindex); break; default: #if defined(linux) /* * This is Linux; we require PF_PACKET support. * If this is a *live* capture, we can look at * special meta-data in the filter expression; * if it's a savefile, we can't. */ if (cstate->bpf_pcap->rfile != NULL) { /* We have a FILE *, so this is a savefile */ bpf_error(cstate, "ifindex not supported on %s when reading savefiles", pcap_datalink_val_to_description_or_dlt(cstate->linktype)); b0 = NULL; /*NOTREACHED*/ } /* match ifindex */ b0 = gen_cmp(cstate, OR_LINKHDR, SKF_AD_OFF + SKF_AD_IFINDEX, BPF_W, ifindex); #else /* defined(linux) */ bpf_error(cstate, "ifindex not supported on %s", pcap_datalink_val_to_description_or_dlt(cstate->linktype)); /*NOTREACHED*/ #endif /* defined(linux) */ } return (b0); } /* * Filter on inbound (dir == 0) or outbound (dir == 1) traffic. * Outbound traffic is sent by this machine, while inbound traffic is * sent by a remote machine (and may include packets destined for a * unicast or multicast link-layer address we are not subscribing to). * These are the same definitions implemented by pcap_setdirection(). * Capturing only unicast traffic destined for this host is probably * better accomplished using a higher-layer filter. */ struct block * gen_inbound(compiler_state_t *cstate, int dir) { register struct block *b0; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); /* * Only some data link types support inbound/outbound qualifiers. */ switch (cstate->linktype) { case DLT_SLIP: b0 = gen_relation_internal(cstate, BPF_JEQ, gen_load_internal(cstate, Q_LINK, gen_loadi_internal(cstate, 0), 1), gen_loadi_internal(cstate, 0), dir); break; case DLT_IPNET: if (dir) { /* match outgoing packets */ b0 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, IPNET_OUTBOUND); } else { /* match incoming packets */ b0 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, IPNET_INBOUND); } break; case DLT_LINUX_SLL: /* match outgoing packets */ b0 = gen_cmp(cstate, OR_LINKHDR, 0, BPF_H, LINUX_SLL_OUTGOING); if (!dir) { /* to filter on inbound traffic, invert the match */ gen_not(b0); } break; case DLT_LINUX_SLL2: /* match outgoing packets */ b0 = gen_cmp(cstate, OR_LINKHDR, 10, BPF_B, LINUX_SLL_OUTGOING); if (!dir) { /* to filter on inbound traffic, invert the match */ gen_not(b0); } break; case DLT_PFLOG: b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, dir), BPF_B, ((dir == 0) ? PF_IN : PF_OUT)); break; case DLT_PPP_PPPD: if (dir) { /* match outgoing packets */ b0 = gen_cmp(cstate, OR_LINKHDR, 0, BPF_B, PPP_PPPD_OUT); } else { /* match incoming packets */ b0 = gen_cmp(cstate, OR_LINKHDR, 0, BPF_B, PPP_PPPD_IN); } break; case DLT_JUNIPER_MFR: case DLT_JUNIPER_MLFR: case DLT_JUNIPER_MLPPP: case DLT_JUNIPER_ATM1: case DLT_JUNIPER_ATM2: case DLT_JUNIPER_PPPOE: case DLT_JUNIPER_PPPOE_ATM: case DLT_JUNIPER_GGSN: case DLT_JUNIPER_ES: case DLT_JUNIPER_MONITOR: case DLT_JUNIPER_SERVICES: case DLT_JUNIPER_ETHER: case DLT_JUNIPER_PPP: case DLT_JUNIPER_FRELAY: case DLT_JUNIPER_CHDLC: case DLT_JUNIPER_VP: case DLT_JUNIPER_ST: case DLT_JUNIPER_ISM: case DLT_JUNIPER_VS: case DLT_JUNIPER_SRX_E2E: case DLT_JUNIPER_FIBRECHANNEL: case DLT_JUNIPER_ATM_CEMIC: /* juniper flags (including direction) are stored * the byte after the 3-byte magic number */ if (dir) { /* match outgoing packets */ b0 = gen_mcmp(cstate, OR_LINKHDR, 3, BPF_B, 0, 0x01); } else { /* match incoming packets */ b0 = gen_mcmp(cstate, OR_LINKHDR, 3, BPF_B, 1, 0x01); } break; default: /* * If we have packet meta-data indicating a direction, * and that metadata can be checked by BPF code, check * it. Otherwise, give up, as this link-layer type has * nothing in the packet data. * * Currently, the only platform where a BPF filter can * check that metadata is Linux with the in-kernel * BPF interpreter. If other packet capture mechanisms * and BPF filters also supported this, it would be * nice. It would be even better if they made that * metadata available so that we could provide it * with newer capture APIs, allowing it to be saved * in pcapng files. */ #if defined(linux) /* * This is Linux; we require PF_PACKET support. * If this is a *live* capture, we can look at * special meta-data in the filter expression; * if it's a savefile, we can't. */ if (cstate->bpf_pcap->rfile != NULL) { /* We have a FILE *, so this is a savefile */ bpf_error(cstate, "inbound/outbound not supported on %s when reading savefiles", pcap_datalink_val_to_description_or_dlt(cstate->linktype)); /*NOTREACHED*/ } /* match outgoing packets */ b0 = gen_cmp(cstate, OR_LINKHDR, SKF_AD_OFF + SKF_AD_PKTTYPE, BPF_H, PACKET_OUTGOING); if (!dir) { /* to filter on inbound traffic, invert the match */ gen_not(b0); } #else /* defined(linux) */ bpf_error(cstate, "inbound/outbound not supported on %s", pcap_datalink_val_to_description_or_dlt(cstate->linktype)); /*NOTREACHED*/ #endif /* defined(linux) */ } return (b0); } /* PF firewall log matched interface */ struct block * gen_pf_ifname(compiler_state_t *cstate, const char *ifname) { struct block *b0; u_int len, off; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); if (cstate->linktype != DLT_PFLOG) { bpf_error(cstate, "ifname supported only on PF linktype"); /*NOTREACHED*/ } len = sizeof(((struct pfloghdr *)0)->ifname); off = offsetof(struct pfloghdr, ifname); if (strlen(ifname) >= len) { bpf_error(cstate, "ifname interface names can only be %d characters", len-1); /*NOTREACHED*/ } b0 = gen_bcmp(cstate, OR_LINKHDR, off, (u_int)strlen(ifname), (const u_char *)ifname); return (b0); } /* PF firewall log ruleset name */ struct block * gen_pf_ruleset(compiler_state_t *cstate, char *ruleset) { struct block *b0; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); if (cstate->linktype != DLT_PFLOG) { bpf_error(cstate, "ruleset supported only on PF linktype"); /*NOTREACHED*/ } if (strlen(ruleset) >= sizeof(((struct pfloghdr *)0)->ruleset)) { bpf_error(cstate, "ruleset names can only be %ld characters", (long)(sizeof(((struct pfloghdr *)0)->ruleset) - 1)); /*NOTREACHED*/ } b0 = gen_bcmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, ruleset), (u_int)strlen(ruleset), (const u_char *)ruleset); return (b0); } /* PF firewall log rule number */ struct block * gen_pf_rnr(compiler_state_t *cstate, int rnr) { struct block *b0; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); if (cstate->linktype != DLT_PFLOG) { bpf_error(cstate, "rnr supported only on PF linktype"); /*NOTREACHED*/ } b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, rulenr), BPF_W, (bpf_u_int32)rnr); return (b0); } /* PF firewall log sub-rule number */ struct block * gen_pf_srnr(compiler_state_t *cstate, int srnr) { struct block *b0; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); if (cstate->linktype != DLT_PFLOG) { bpf_error(cstate, "srnr supported only on PF linktype"); /*NOTREACHED*/ } b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, subrulenr), BPF_W, (bpf_u_int32)srnr); return (b0); } /* PF firewall log reason code */ struct block * gen_pf_reason(compiler_state_t *cstate, int reason) { struct block *b0; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); if (cstate->linktype != DLT_PFLOG) { bpf_error(cstate, "reason supported only on PF linktype"); /*NOTREACHED*/ } b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, reason), BPF_B, (bpf_u_int32)reason); return (b0); } /* PF firewall log action */ struct block * gen_pf_action(compiler_state_t *cstate, int action) { struct block *b0; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); if (cstate->linktype != DLT_PFLOG) { bpf_error(cstate, "action supported only on PF linktype"); /*NOTREACHED*/ } b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, action), BPF_B, (bpf_u_int32)action); return (b0); } /* IEEE 802.11 wireless header */ struct block * gen_p80211_type(compiler_state_t *cstate, bpf_u_int32 type, bpf_u_int32 mask) { struct block *b0; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); switch (cstate->linktype) { case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO_AVS: case DLT_IEEE802_11_RADIO: b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, type, mask); break; default: bpf_error(cstate, "802.11 link-layer types supported only on 802.11"); /*NOTREACHED*/ } return (b0); } struct block * gen_p80211_fcdir(compiler_state_t *cstate, bpf_u_int32 fcdir) { struct block *b0; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); switch (cstate->linktype) { case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO_AVS: case DLT_IEEE802_11_RADIO: break; default: bpf_error(cstate, "frame direction supported only with 802.11 headers"); /*NOTREACHED*/ } b0 = gen_mcmp(cstate, OR_LINKHDR, 1, BPF_B, fcdir, IEEE80211_FC1_DIR_MASK); return (b0); } struct block * gen_acode(compiler_state_t *cstate, const char *s, struct qual q) { struct block *b; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); switch (cstate->linktype) { case DLT_ARCNET: case DLT_ARCNET_LINUX: if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) && q.proto == Q_LINK) { cstate->e = pcap_ether_aton(s); if (cstate->e == NULL) bpf_error(cstate, "malloc"); b = gen_ahostop(cstate, cstate->e, (int)q.dir); free(cstate->e); cstate->e = NULL; return (b); } else bpf_error(cstate, "ARCnet address used in non-arc expression"); /*NOTREACHED*/ default: bpf_error(cstate, "aid supported only on ARCnet"); /*NOTREACHED*/ } } static struct block * gen_ahostop(compiler_state_t *cstate, const u_char *eaddr, int dir) { register struct block *b0, *b1; switch (dir) { /* src comes first, different from Ethernet */ case Q_SRC: return gen_bcmp(cstate, OR_LINKHDR, 0, 1, eaddr); case Q_DST: return gen_bcmp(cstate, OR_LINKHDR, 1, 1, eaddr); case Q_AND: b0 = gen_ahostop(cstate, eaddr, Q_SRC); b1 = gen_ahostop(cstate, eaddr, Q_DST); gen_and(b0, b1); return b1; case Q_DEFAULT: case Q_OR: b0 = gen_ahostop(cstate, eaddr, Q_SRC); b1 = gen_ahostop(cstate, eaddr, Q_DST); gen_or(b0, b1); return b1; case Q_ADDR1: bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11"); /*NOTREACHED*/ case Q_ADDR2: bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11"); /*NOTREACHED*/ case Q_ADDR3: bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11"); /*NOTREACHED*/ case Q_ADDR4: bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11"); /*NOTREACHED*/ case Q_RA: bpf_error(cstate, "'ra' is only supported on 802.11"); /*NOTREACHED*/ case Q_TA: bpf_error(cstate, "'ta' is only supported on 802.11"); /*NOTREACHED*/ } abort(); /*NOTREACHED*/ } static struct block * gen_vlan_tpid_test(compiler_state_t *cstate) { struct block *b0, *b1; /* check for VLAN, including 802.1ad and QinQ */ b0 = gen_linktype(cstate, ETHERTYPE_8021Q); b1 = gen_linktype(cstate, ETHERTYPE_8021AD); gen_or(b0,b1); b0 = b1; b1 = gen_linktype(cstate, ETHERTYPE_8021QINQ); gen_or(b0,b1); return b1; } static struct block * gen_vlan_vid_test(compiler_state_t *cstate, bpf_u_int32 vlan_num) { if (vlan_num > 0x0fff) { bpf_error(cstate, "VLAN tag %u greater than maximum %u", vlan_num, 0x0fff); } return gen_mcmp(cstate, OR_LINKPL, 0, BPF_H, vlan_num, 0x0fff); } static struct block * gen_vlan_no_bpf_extensions(compiler_state_t *cstate, bpf_u_int32 vlan_num, int has_vlan_tag) { struct block *b0, *b1; b0 = gen_vlan_tpid_test(cstate); if (has_vlan_tag) { b1 = gen_vlan_vid_test(cstate, vlan_num); gen_and(b0, b1); b0 = b1; } /* * Both payload and link header type follow the VLAN tags so that * both need to be updated. */ cstate->off_linkpl.constant_part += 4; cstate->off_linktype.constant_part += 4; return b0; } #if defined(SKF_AD_VLAN_TAG_PRESENT) /* add v to variable part of off */ static void gen_vlan_vloffset_add(compiler_state_t *cstate, bpf_abs_offset *off, bpf_u_int32 v, struct slist *s) { struct slist *s2; if (!off->is_variable) off->is_variable = 1; if (off->reg == -1) off->reg = alloc_reg(cstate); s2 = new_stmt(cstate, BPF_LD|BPF_MEM); s2->s.k = off->reg; sappend(s, s2); s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_IMM); s2->s.k = v; sappend(s, s2); s2 = new_stmt(cstate, BPF_ST); s2->s.k = off->reg; sappend(s, s2); } /* * patch block b_tpid (VLAN TPID test) to update variable parts of link payload * and link type offsets first */ static void gen_vlan_patch_tpid_test(compiler_state_t *cstate, struct block *b_tpid) { struct slist s; /* offset determined at run time, shift variable part */ s.next = NULL; cstate->is_vlan_vloffset = 1; gen_vlan_vloffset_add(cstate, &cstate->off_linkpl, 4, &s); gen_vlan_vloffset_add(cstate, &cstate->off_linktype, 4, &s); /* we get a pointer to a chain of or-ed blocks, patch first of them */ sappend(s.next, b_tpid->head->stmts); b_tpid->head->stmts = s.next; } /* * patch block b_vid (VLAN id test) to load VID value either from packet * metadata (using BPF extensions) if SKF_AD_VLAN_TAG_PRESENT is true */ static void gen_vlan_patch_vid_test(compiler_state_t *cstate, struct block *b_vid) { struct slist *s, *s2, *sjeq; unsigned cnt; s = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS); s->s.k = SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT; /* true -> next instructions, false -> beginning of b_vid */ sjeq = new_stmt(cstate, JMP(BPF_JEQ)); sjeq->s.k = 1; sjeq->s.jf = b_vid->stmts; sappend(s, sjeq); s2 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS); s2->s.k = SKF_AD_OFF + SKF_AD_VLAN_TAG; sappend(s, s2); sjeq->s.jt = s2; /* Jump to the test in b_vid. We need to jump one instruction before * the end of the b_vid block so that we only skip loading the TCI * from packet data and not the 'and' instruction extractging VID. */ cnt = 0; for (s2 = b_vid->stmts; s2; s2 = s2->next) cnt++; s2 = new_stmt(cstate, JMP(BPF_JA)); s2->s.k = cnt - 1; sappend(s, s2); /* insert our statements at the beginning of b_vid */ sappend(s, b_vid->stmts); b_vid->stmts = s; } /* * Generate check for "vlan" or "vlan <id>" on systems with support for BPF * extensions. Even if kernel supports VLAN BPF extensions, (outermost) VLAN * tag can be either in metadata or in packet data; therefore if the * SKF_AD_VLAN_TAG_PRESENT test is negative, we need to check link * header for VLAN tag. As the decision is done at run time, we need * update variable part of the offsets */ static struct block * gen_vlan_bpf_extensions(compiler_state_t *cstate, bpf_u_int32 vlan_num, int has_vlan_tag) { struct block *b0, *b_tpid, *b_vid = NULL; struct slist *s; /* generate new filter code based on extracting packet * metadata */ s = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS); s->s.k = SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT; b0 = new_block(cstate, JMP(BPF_JEQ)); b0->stmts = s; b0->s.k = 1; /* * This is tricky. We need to insert the statements updating variable * parts of offsets before the traditional TPID and VID tests so * that they are called whenever SKF_AD_VLAN_TAG_PRESENT fails but * we do not want this update to affect those checks. That's why we * generate both test blocks first and insert the statements updating * variable parts of both offsets after that. This wouldn't work if * there already were variable length link header when entering this * function but gen_vlan_bpf_extensions() isn't called in that case. */ b_tpid = gen_vlan_tpid_test(cstate); if (has_vlan_tag) b_vid = gen_vlan_vid_test(cstate, vlan_num); gen_vlan_patch_tpid_test(cstate, b_tpid); gen_or(b0, b_tpid); b0 = b_tpid; if (has_vlan_tag) { gen_vlan_patch_vid_test(cstate, b_vid); gen_and(b0, b_vid); b0 = b_vid; } return b0; } #endif /* * support IEEE 802.1Q VLAN trunk over ethernet */ struct block * gen_vlan(compiler_state_t *cstate, bpf_u_int32 vlan_num, int has_vlan_tag) { struct block *b0; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); /* can't check for VLAN-encapsulated packets inside MPLS */ if (cstate->label_stack_depth > 0) bpf_error(cstate, "no VLAN match after MPLS"); /* * Check for a VLAN packet, and then change the offsets to point * to the type and data fields within the VLAN packet. Just * increment the offsets, so that we can support a hierarchy, e.g. * "vlan 300 && vlan 200" to capture VLAN 200 encapsulated within * VLAN 100. * * XXX - this is a bit of a kludge. If we were to split the * compiler into a parser that parses an expression and * generates an expression tree, and a code generator that * takes an expression tree (which could come from our * parser or from some other parser) and generates BPF code, * we could perhaps make the offsets parameters of routines * and, in the handler for an "AND" node, pass to subnodes * other than the VLAN node the adjusted offsets. * * This would mean that "vlan" would, instead of changing the * behavior of *all* tests after it, change only the behavior * of tests ANDed with it. That would change the documented * semantics of "vlan", which might break some expressions. * However, it would mean that "(vlan and ip) or ip" would check * both for VLAN-encapsulated IP and IP-over-Ethernet, rather than * checking only for VLAN-encapsulated IP, so that could still * be considered worth doing; it wouldn't break expressions * that are of the form "vlan and ..." or "vlan N and ...", * which I suspect are the most common expressions involving * "vlan". "vlan or ..." doesn't necessarily do what the user * would really want, now, as all the "or ..." tests would * be done assuming a VLAN, even though the "or" could be viewed * as meaning "or, if this isn't a VLAN packet...". */ switch (cstate->linktype) { case DLT_EN10MB: case DLT_NETANALYZER: case DLT_NETANALYZER_TRANSPARENT: #if defined(SKF_AD_VLAN_TAG_PRESENT) /* Verify that this is the outer part of the packet and * not encapsulated somehow. */ if (cstate->vlan_stack_depth == 0 && !cstate->off_linkhdr.is_variable && cstate->off_linkhdr.constant_part == cstate->off_outermostlinkhdr.constant_part) { /* * Do we need special VLAN handling? */ if (cstate->bpf_pcap->bpf_codegen_flags & BPF_SPECIAL_VLAN_HANDLING) b0 = gen_vlan_bpf_extensions(cstate, vlan_num, has_vlan_tag); else b0 = gen_vlan_no_bpf_extensions(cstate, vlan_num, has_vlan_tag); } else #endif b0 = gen_vlan_no_bpf_extensions(cstate, vlan_num, has_vlan_tag); break; case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO_AVS: case DLT_IEEE802_11_RADIO: b0 = gen_vlan_no_bpf_extensions(cstate, vlan_num, has_vlan_tag); break; default: bpf_error(cstate, "no VLAN support for %s", pcap_datalink_val_to_description_or_dlt(cstate->linktype)); /*NOTREACHED*/ } cstate->vlan_stack_depth++; return (b0); } /* * support for MPLS * * The label_num_arg dance is to avoid annoying whining by compilers that * label_num might be clobbered by longjmp - yeah, it might, but *WHO CARES*? * It's not *used* after setjmp returns. */ struct block * gen_mpls(compiler_state_t *cstate, bpf_u_int32 label_num_arg, int has_label_num) { volatile bpf_u_int32 label_num = label_num_arg; struct block *b0, *b1; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); if (cstate->label_stack_depth > 0) { /* just match the bottom-of-stack bit clear */ b0 = gen_mcmp(cstate, OR_PREVMPLSHDR, 2, BPF_B, 0, 0x01); } else { /* * We're not in an MPLS stack yet, so check the link-layer * type against MPLS. */ switch (cstate->linktype) { case DLT_C_HDLC: /* fall through */ case DLT_HDLC: case DLT_EN10MB: case DLT_NETANALYZER: case DLT_NETANALYZER_TRANSPARENT: b0 = gen_linktype(cstate, ETHERTYPE_MPLS); break; case DLT_PPP: b0 = gen_linktype(cstate, PPP_MPLS_UCAST); break; /* FIXME add other DLT_s ... * for Frame-Relay/and ATM this may get messy due to SNAP headers * leave it for now */ default: bpf_error(cstate, "no MPLS support for %s", pcap_datalink_val_to_description_or_dlt(cstate->linktype)); /*NOTREACHED*/ } } /* If a specific MPLS label is requested, check it */ if (has_label_num) { if (label_num > 0xFFFFF) { bpf_error(cstate, "MPLS label %u greater than maximum %u", label_num, 0xFFFFF); } label_num = label_num << 12; /* label is shifted 12 bits on the wire */ b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_W, label_num, 0xfffff000); /* only compare the first 20 bits */ gen_and(b0, b1); b0 = b1; } /* * Change the offsets to point to the type and data fields within * the MPLS packet. Just increment the offsets, so that we * can support a hierarchy, e.g. "mpls 100000 && mpls 1024" to * capture packets with an outer label of 100000 and an inner * label of 1024. * * Increment the MPLS stack depth as well; this indicates that * we're checking MPLS-encapsulated headers, to make sure higher * level code generators don't try to match against IP-related * protocols such as Q_ARP, Q_RARP etc. * * XXX - this is a bit of a kludge. See comments in gen_vlan(). */ cstate->off_nl_nosnap += 4; cstate->off_nl += 4; cstate->label_stack_depth++; return (b0); } /* * Support PPPOE discovery and session. */ struct block * gen_pppoed(compiler_state_t *cstate) { /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); /* check for PPPoE discovery */ return gen_linktype(cstate, ETHERTYPE_PPPOED); } struct block * gen_pppoes(compiler_state_t *cstate, bpf_u_int32 sess_num, int has_sess_num) { struct block *b0, *b1; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); /* * Test against the PPPoE session link-layer type. */ b0 = gen_linktype(cstate, ETHERTYPE_PPPOES); /* If a specific session is requested, check PPPoE session id */ if (has_sess_num) { if (sess_num > 0x0000ffff) { bpf_error(cstate, "PPPoE session number %u greater than maximum %u", sess_num, 0x0000ffff); } b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_W, sess_num, 0x0000ffff); gen_and(b0, b1); b0 = b1; } /* * Change the offsets to point to the type and data fields within * the PPP packet, and note that this is PPPoE rather than * raw PPP. * * XXX - this is a bit of a kludge. See the comments in * gen_vlan(). * * The "network-layer" protocol is PPPoE, which has a 6-byte * PPPoE header, followed by a PPP packet. * * There is no HDLC encapsulation for the PPP packet (it's * encapsulated in PPPoES instead), so the link-layer type * starts at the first byte of the PPP packet. For PPPoE, * that offset is relative to the beginning of the total * link-layer payload, including any 802.2 LLC header, so * it's 6 bytes past cstate->off_nl. */ PUSH_LINKHDR(cstate, DLT_PPP, cstate->off_linkpl.is_variable, cstate->off_linkpl.constant_part + cstate->off_nl + 6, /* 6 bytes past the PPPoE header */ cstate->off_linkpl.reg); cstate->off_linktype = cstate->off_linkhdr; cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 2; cstate->off_nl = 0; cstate->off_nl_nosnap = 0; /* no 802.2 LLC */ return b0; } /* Check that this is Geneve and the VNI is correct if * specified. Parameterized to handle both IPv4 and IPv6. */ static struct block * gen_geneve_check(compiler_state_t *cstate, struct block *(*gen_portfn)(compiler_state_t *, u_int, int, int), enum e_offrel offrel, bpf_u_int32 vni, int has_vni) { struct block *b0, *b1; b0 = gen_portfn(cstate, GENEVE_PORT, IPPROTO_UDP, Q_DST); /* Check that we are operating on version 0. Otherwise, we * can't decode the rest of the fields. The version is 2 bits * in the first byte of the Geneve header. */ b1 = gen_mcmp(cstate, offrel, 8, BPF_B, 0, 0xc0); gen_and(b0, b1); b0 = b1; if (has_vni) { if (vni > 0xffffff) { bpf_error(cstate, "Geneve VNI %u greater than maximum %u", vni, 0xffffff); } vni <<= 8; /* VNI is in the upper 3 bytes */ b1 = gen_mcmp(cstate, offrel, 12, BPF_W, vni, 0xffffff00); gen_and(b0, b1); b0 = b1; } return b0; } /* The IPv4 and IPv6 Geneve checks need to do two things: * - Verify that this actually is Geneve with the right VNI. * - Place the IP header length (plus variable link prefix if * needed) into register A to be used later to compute * the inner packet offsets. */ static struct block * gen_geneve4(compiler_state_t *cstate, bpf_u_int32 vni, int has_vni) { struct block *b0, *b1; struct slist *s, *s1; b0 = gen_geneve_check(cstate, gen_port, OR_TRAN_IPV4, vni, has_vni); /* Load the IP header length into A. */ s = gen_loadx_iphdrlen(cstate); s1 = new_stmt(cstate, BPF_MISC|BPF_TXA); sappend(s, s1); /* Forcibly append these statements to the true condition * of the protocol check by creating a new block that is * always true and ANDing them. */ b1 = new_block(cstate, BPF_JMP|BPF_JEQ|BPF_X); b1->stmts = s; b1->s.k = 0; gen_and(b0, b1); return b1; } static struct block * gen_geneve6(compiler_state_t *cstate, bpf_u_int32 vni, int has_vni) { struct block *b0, *b1; struct slist *s, *s1; b0 = gen_geneve_check(cstate, gen_port6, OR_TRAN_IPV6, vni, has_vni); /* Load the IP header length. We need to account for a * variable length link prefix if there is one. */ s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl); if (s) { s1 = new_stmt(cstate, BPF_LD|BPF_IMM); s1->s.k = 40; sappend(s, s1); s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X); s1->s.k = 0; sappend(s, s1); } else { s = new_stmt(cstate, BPF_LD|BPF_IMM); s->s.k = 40; } /* Forcibly append these statements to the true condition * of the protocol check by creating a new block that is * always true and ANDing them. */ s1 = new_stmt(cstate, BPF_MISC|BPF_TAX); sappend(s, s1); b1 = new_block(cstate, BPF_JMP|BPF_JEQ|BPF_X); b1->stmts = s; b1->s.k = 0; gen_and(b0, b1); return b1; } /* We need to store three values based on the Geneve header:: * - The offset of the linktype. * - The offset of the end of the Geneve header. * - The offset of the end of the encapsulated MAC header. */ static struct slist * gen_geneve_offsets(compiler_state_t *cstate) { struct slist *s, *s1, *s_proto; /* First we need to calculate the offset of the Geneve header * itself. This is composed of the IP header previously calculated * (include any variable link prefix) and stored in A plus the * fixed sized headers (fixed link prefix, MAC length, and UDP * header). */ s = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K); s->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 8; /* Stash this in X since we'll need it later. */ s1 = new_stmt(cstate, BPF_MISC|BPF_TAX); sappend(s, s1); /* The EtherType in Geneve is 2 bytes in. Calculate this and * store it. */ s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K); s1->s.k = 2; sappend(s, s1); cstate->off_linktype.reg = alloc_reg(cstate); cstate->off_linktype.is_variable = 1; cstate->off_linktype.constant_part = 0; s1 = new_stmt(cstate, BPF_ST); s1->s.k = cstate->off_linktype.reg; sappend(s, s1); /* Load the Geneve option length and mask and shift to get the * number of bytes. It is stored in the first byte of the Geneve * header. */ s1 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B); s1->s.k = 0; sappend(s, s1); s1 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K); s1->s.k = 0x3f; sappend(s, s1); s1 = new_stmt(cstate, BPF_ALU|BPF_MUL|BPF_K); s1->s.k = 4; sappend(s, s1); /* Add in the rest of the Geneve base header. */ s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K); s1->s.k = 8; sappend(s, s1); /* Add the Geneve header length to its offset and store. */ s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X); s1->s.k = 0; sappend(s, s1); /* Set the encapsulated type as Ethernet. Even though we may * not actually have Ethernet inside there are two reasons this * is useful: * - The linktype field is always in EtherType format regardless * of whether it is in Geneve or an inner Ethernet frame. * - The only link layer that we have specific support for is * Ethernet. We will confirm that the packet actually is * Ethernet at runtime before executing these checks. */ PUSH_LINKHDR(cstate, DLT_EN10MB, 1, 0, alloc_reg(cstate)); s1 = new_stmt(cstate, BPF_ST); s1->s.k = cstate->off_linkhdr.reg; sappend(s, s1); /* Calculate whether we have an Ethernet header or just raw IP/ * MPLS/etc. If we have Ethernet, advance the end of the MAC offset * and linktype by 14 bytes so that the network header can be found * seamlessly. Otherwise, keep what we've calculated already. */ /* We have a bare jmp so we can't use the optimizer. */ cstate->no_optimize = 1; /* Load the EtherType in the Geneve header, 2 bytes in. */ s1 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_H); s1->s.k = 2; sappend(s, s1); /* Load X with the end of the Geneve header. */ s1 = new_stmt(cstate, BPF_LDX|BPF_MEM); s1->s.k = cstate->off_linkhdr.reg; sappend(s, s1); /* Check if the EtherType is Transparent Ethernet Bridging. At the * end of this check, we should have the total length in X. In * the non-Ethernet case, it's already there. */ s_proto = new_stmt(cstate, JMP(BPF_JEQ)); s_proto->s.k = ETHERTYPE_TEB; sappend(s, s_proto); s1 = new_stmt(cstate, BPF_MISC|BPF_TXA); sappend(s, s1); s_proto->s.jt = s1; /* Since this is Ethernet, use the EtherType of the payload * directly as the linktype. Overwrite what we already have. */ s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K); s1->s.k = 12; sappend(s, s1); s1 = new_stmt(cstate, BPF_ST); s1->s.k = cstate->off_linktype.reg; sappend(s, s1); /* Advance two bytes further to get the end of the Ethernet * header. */ s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K); s1->s.k = 2; sappend(s, s1); /* Move the result to X. */ s1 = new_stmt(cstate, BPF_MISC|BPF_TAX); sappend(s, s1); /* Store the final result of our linkpl calculation. */ cstate->off_linkpl.reg = alloc_reg(cstate); cstate->off_linkpl.is_variable = 1; cstate->off_linkpl.constant_part = 0; s1 = new_stmt(cstate, BPF_STX); s1->s.k = cstate->off_linkpl.reg; sappend(s, s1); s_proto->s.jf = s1; cstate->off_nl = 0; return s; } /* Check to see if this is a Geneve packet. */ struct block * gen_geneve(compiler_state_t *cstate, bpf_u_int32 vni, int has_vni) { struct block *b0, *b1; struct slist *s; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); b0 = gen_geneve4(cstate, vni, has_vni); b1 = gen_geneve6(cstate, vni, has_vni); gen_or(b0, b1); b0 = b1; /* Later filters should act on the payload of the Geneve frame, * update all of the header pointers. Attach this code so that * it gets executed in the event that the Geneve filter matches. */ s = gen_geneve_offsets(cstate); b1 = gen_true(cstate); sappend(s, b1->stmts); b1->stmts = s; gen_and(b0, b1); cstate->is_geneve = 1; return b1; } /* Check that the encapsulated frame has a link layer header * for Ethernet filters. */ static struct block * gen_geneve_ll_check(compiler_state_t *cstate) { struct block *b0; struct slist *s, *s1; /* The easiest way to see if there is a link layer present * is to check if the link layer header and payload are not * the same. */ /* Geneve always generates pure variable offsets so we can * compare only the registers. */ s = new_stmt(cstate, BPF_LD|BPF_MEM); s->s.k = cstate->off_linkhdr.reg; s1 = new_stmt(cstate, BPF_LDX|BPF_MEM); s1->s.k = cstate->off_linkpl.reg; sappend(s, s1); b0 = new_block(cstate, BPF_JMP|BPF_JEQ|BPF_X); b0->stmts = s; b0->s.k = 0; gen_not(b0); return b0; } static struct block * gen_atmfield_code_internal(compiler_state_t *cstate, int atmfield, bpf_u_int32 jvalue, int jtype, int reverse) { struct block *b0; switch (atmfield) { case A_VPI: if (!cstate->is_atm) bpf_error(cstate, "'vpi' supported only on raw ATM"); if (cstate->off_vpi == OFFSET_NOT_SET) abort(); b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_vpi, BPF_B, 0xffffffffU, jtype, reverse, jvalue); break; case A_VCI: if (!cstate->is_atm) bpf_error(cstate, "'vci' supported only on raw ATM"); if (cstate->off_vci == OFFSET_NOT_SET) abort(); b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_vci, BPF_H, 0xffffffffU, jtype, reverse, jvalue); break; case A_PROTOTYPE: if (cstate->off_proto == OFFSET_NOT_SET) abort(); /* XXX - this isn't on FreeBSD */ b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_proto, BPF_B, 0x0fU, jtype, reverse, jvalue); break; case A_MSGTYPE: if (cstate->off_payload == OFFSET_NOT_SET) abort(); b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_payload + MSG_TYPE_POS, BPF_B, 0xffffffffU, jtype, reverse, jvalue); break; case A_CALLREFTYPE: if (!cstate->is_atm) bpf_error(cstate, "'callref' supported only on raw ATM"); if (cstate->off_proto == OFFSET_NOT_SET) abort(); b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_proto, BPF_B, 0xffffffffU, jtype, reverse, jvalue); break; default: abort(); } return b0; } static struct block * gen_atmtype_metac(compiler_state_t *cstate) { struct block *b0, *b1; b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0); b1 = gen_atmfield_code_internal(cstate, A_VCI, 1, BPF_JEQ, 0); gen_and(b0, b1); return b1; } static struct block * gen_atmtype_sc(compiler_state_t *cstate) { struct block *b0, *b1; b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0); b1 = gen_atmfield_code_internal(cstate, A_VCI, 5, BPF_JEQ, 0); gen_and(b0, b1); return b1; } static struct block * gen_atmtype_llc(compiler_state_t *cstate) { struct block *b0; b0 = gen_atmfield_code_internal(cstate, A_PROTOTYPE, PT_LLC, BPF_JEQ, 0); cstate->linktype = cstate->prevlinktype; return b0; } struct block * gen_atmfield_code(compiler_state_t *cstate, int atmfield, bpf_u_int32 jvalue, int jtype, int reverse) { /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); return gen_atmfield_code_internal(cstate, atmfield, jvalue, jtype, reverse); } struct block * gen_atmtype_abbrev(compiler_state_t *cstate, int type) { struct block *b0, *b1; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); switch (type) { case A_METAC: /* Get all packets in Meta signalling Circuit */ if (!cstate->is_atm) bpf_error(cstate, "'metac' supported only on raw ATM"); b1 = gen_atmtype_metac(cstate); break; case A_BCC: /* Get all packets in Broadcast Circuit*/ if (!cstate->is_atm) bpf_error(cstate, "'bcc' supported only on raw ATM"); b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0); b1 = gen_atmfield_code_internal(cstate, A_VCI, 2, BPF_JEQ, 0); gen_and(b0, b1); break; case A_OAMF4SC: /* Get all cells in Segment OAM F4 circuit*/ if (!cstate->is_atm) bpf_error(cstate, "'oam4sc' supported only on raw ATM"); b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0); b1 = gen_atmfield_code_internal(cstate, A_VCI, 3, BPF_JEQ, 0); gen_and(b0, b1); break; case A_OAMF4EC: /* Get all cells in End-to-End OAM F4 Circuit*/ if (!cstate->is_atm) bpf_error(cstate, "'oam4ec' supported only on raw ATM"); b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0); b1 = gen_atmfield_code_internal(cstate, A_VCI, 4, BPF_JEQ, 0); gen_and(b0, b1); break; case A_SC: /* Get all packets in connection Signalling Circuit */ if (!cstate->is_atm) bpf_error(cstate, "'sc' supported only on raw ATM"); b1 = gen_atmtype_sc(cstate); break; case A_ILMIC: /* Get all packets in ILMI Circuit */ if (!cstate->is_atm) bpf_error(cstate, "'ilmic' supported only on raw ATM"); b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0); b1 = gen_atmfield_code_internal(cstate, A_VCI, 16, BPF_JEQ, 0); gen_and(b0, b1); break; case A_LANE: /* Get all LANE packets */ if (!cstate->is_atm) bpf_error(cstate, "'lane' supported only on raw ATM"); b1 = gen_atmfield_code_internal(cstate, A_PROTOTYPE, PT_LANE, BPF_JEQ, 0); /* * Arrange that all subsequent tests assume LANE * rather than LLC-encapsulated packets, and set * the offsets appropriately for LANE-encapsulated * Ethernet. * * We assume LANE means Ethernet, not Token Ring. */ PUSH_LINKHDR(cstate, DLT_EN10MB, 0, cstate->off_payload + 2, /* Ethernet header */ -1); cstate->off_linktype.constant_part = cstate->off_linkhdr.constant_part + 12; cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 14; /* Ethernet */ cstate->off_nl = 0; /* Ethernet II */ cstate->off_nl_nosnap = 3; /* 802.3+802.2 */ break; case A_LLC: /* Get all LLC-encapsulated packets */ if (!cstate->is_atm) bpf_error(cstate, "'llc' supported only on raw ATM"); b1 = gen_atmtype_llc(cstate); break; default: abort(); } return b1; } /* * Filtering for MTP2 messages based on li value * FISU, length is null * LSSU, length is 1 or 2 * MSU, length is 3 or more * For MTP2_HSL, sequences are on 2 bytes, and length on 9 bits */ struct block * gen_mtp2type_abbrev(compiler_state_t *cstate, int type) { struct block *b0, *b1; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); switch (type) { case M_FISU: if ( (cstate->linktype != DLT_MTP2) && (cstate->linktype != DLT_ERF) && (cstate->linktype != DLT_MTP2_WITH_PHDR) ) bpf_error(cstate, "'fisu' supported only on MTP2"); /* gen_ncmp(cstate, offrel, offset, size, mask, jtype, reverse, value) */ b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3fU, BPF_JEQ, 0, 0U); break; case M_LSSU: if ( (cstate->linktype != DLT_MTP2) && (cstate->linktype != DLT_ERF) && (cstate->linktype != DLT_MTP2_WITH_PHDR) ) bpf_error(cstate, "'lssu' supported only on MTP2"); b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3fU, BPF_JGT, 1, 2U); b1 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3fU, BPF_JGT, 0, 0U); gen_and(b1, b0); break; case M_MSU: if ( (cstate->linktype != DLT_MTP2) && (cstate->linktype != DLT_ERF) && (cstate->linktype != DLT_MTP2_WITH_PHDR) ) bpf_error(cstate, "'msu' supported only on MTP2"); b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3fU, BPF_JGT, 0, 2U); break; case MH_FISU: if ( (cstate->linktype != DLT_MTP2) && (cstate->linktype != DLT_ERF) && (cstate->linktype != DLT_MTP2_WITH_PHDR) ) bpf_error(cstate, "'hfisu' supported only on MTP2_HSL"); /* gen_ncmp(cstate, offrel, offset, size, mask, jtype, reverse, value) */ b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80U, BPF_JEQ, 0, 0U); break; case MH_LSSU: if ( (cstate->linktype != DLT_MTP2) && (cstate->linktype != DLT_ERF) && (cstate->linktype != DLT_MTP2_WITH_PHDR) ) bpf_error(cstate, "'hlssu' supported only on MTP2_HSL"); b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80U, BPF_JGT, 1, 0x0100U); b1 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80U, BPF_JGT, 0, 0U); gen_and(b1, b0); break; case MH_MSU: if ( (cstate->linktype != DLT_MTP2) && (cstate->linktype != DLT_ERF) && (cstate->linktype != DLT_MTP2_WITH_PHDR) ) bpf_error(cstate, "'hmsu' supported only on MTP2_HSL"); b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80U, BPF_JGT, 0, 0x0100U); break; default: abort(); } return b0; } /* * The jvalue_arg dance is to avoid annoying whining by compilers that * jvalue might be clobbered by longjmp - yeah, it might, but *WHO CARES*? * It's not *used* after setjmp returns. */ struct block * gen_mtp3field_code(compiler_state_t *cstate, int mtp3field, bpf_u_int32 jvalue_arg, int jtype, int reverse) { volatile bpf_u_int32 jvalue = jvalue_arg; struct block *b0; bpf_u_int32 val1 , val2 , val3; u_int newoff_sio; u_int newoff_opc; u_int newoff_dpc; u_int newoff_sls; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); newoff_sio = cstate->off_sio; newoff_opc = cstate->off_opc; newoff_dpc = cstate->off_dpc; newoff_sls = cstate->off_sls; switch (mtp3field) { case MH_SIO: newoff_sio += 3; /* offset for MTP2_HSL */ /* FALLTHROUGH */ case M_SIO: if (cstate->off_sio == OFFSET_NOT_SET) bpf_error(cstate, "'sio' supported only on SS7"); /* sio coded on 1 byte so max value 255 */ if(jvalue > 255) bpf_error(cstate, "sio value %u too big; max value = 255", jvalue); b0 = gen_ncmp(cstate, OR_PACKET, newoff_sio, BPF_B, 0xffffffffU, jtype, reverse, jvalue); break; case MH_OPC: newoff_opc += 3; /* FALLTHROUGH */ case M_OPC: if (cstate->off_opc == OFFSET_NOT_SET) bpf_error(cstate, "'opc' supported only on SS7"); /* opc coded on 14 bits so max value 16383 */ if (jvalue > 16383) bpf_error(cstate, "opc value %u too big; max value = 16383", jvalue); /* the following instructions are made to convert jvalue * to the form used to write opc in an ss7 message*/ val1 = jvalue & 0x00003c00; val1 = val1 >>10; val2 = jvalue & 0x000003fc; val2 = val2 <<6; val3 = jvalue & 0x00000003; val3 = val3 <<22; jvalue = val1 + val2 + val3; b0 = gen_ncmp(cstate, OR_PACKET, newoff_opc, BPF_W, 0x00c0ff0fU, jtype, reverse, jvalue); break; case MH_DPC: newoff_dpc += 3; /* FALLTHROUGH */ case M_DPC: if (cstate->off_dpc == OFFSET_NOT_SET) bpf_error(cstate, "'dpc' supported only on SS7"); /* dpc coded on 14 bits so max value 16383 */ if (jvalue > 16383) bpf_error(cstate, "dpc value %u too big; max value = 16383", jvalue); /* the following instructions are made to convert jvalue * to the forme used to write dpc in an ss7 message*/ val1 = jvalue & 0x000000ff; val1 = val1 << 24; val2 = jvalue & 0x00003f00; val2 = val2 << 8; jvalue = val1 + val2; b0 = gen_ncmp(cstate, OR_PACKET, newoff_dpc, BPF_W, 0xff3f0000U, jtype, reverse, jvalue); break; case MH_SLS: newoff_sls += 3; /* FALLTHROUGH */ case M_SLS: if (cstate->off_sls == OFFSET_NOT_SET) bpf_error(cstate, "'sls' supported only on SS7"); /* sls coded on 4 bits so max value 15 */ if (jvalue > 15) bpf_error(cstate, "sls value %u too big; max value = 15", jvalue); /* the following instruction is made to convert jvalue * to the forme used to write sls in an ss7 message*/ jvalue = jvalue << 4; b0 = gen_ncmp(cstate, OR_PACKET, newoff_sls, BPF_B, 0xf0U, jtype, reverse, jvalue); break; default: abort(); } return b0; } static struct block * gen_msg_abbrev(compiler_state_t *cstate, int type) { struct block *b1; /* * Q.2931 signalling protocol messages for handling virtual circuits * establishment and teardown */ switch (type) { case A_SETUP: b1 = gen_atmfield_code_internal(cstate, A_MSGTYPE, SETUP, BPF_JEQ, 0); break; case A_CALLPROCEED: b1 = gen_atmfield_code_internal(cstate, A_MSGTYPE, CALL_PROCEED, BPF_JEQ, 0); break; case A_CONNECT: b1 = gen_atmfield_code_internal(cstate, A_MSGTYPE, CONNECT, BPF_JEQ, 0); break; case A_CONNECTACK: b1 = gen_atmfield_code_internal(cstate, A_MSGTYPE, CONNECT_ACK, BPF_JEQ, 0); break; case A_RELEASE: b1 = gen_atmfield_code_internal(cstate, A_MSGTYPE, RELEASE, BPF_JEQ, 0); break; case A_RELEASE_DONE: b1 = gen_atmfield_code_internal(cstate, A_MSGTYPE, RELEASE_DONE, BPF_JEQ, 0); break; default: abort(); } return b1; } struct block * gen_atmmulti_abbrev(compiler_state_t *cstate, int type) { struct block *b0, *b1; /* * Catch errors reported by us and routines below us, and return NULL * on an error. */ if (setjmp(cstate->top_ctx)) return (NULL); switch (type) { case A_OAM: if (!cstate->is_atm) bpf_error(cstate, "'oam' supported only on raw ATM"); /* OAM F4 type */ b0 = gen_atmfield_code_internal(cstate, A_VCI, 3, BPF_JEQ, 0); b1 = gen_atmfield_code_internal(cstate, A_VCI, 4, BPF_JEQ, 0); gen_or(b0, b1); b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0); gen_and(b0, b1); break; case A_OAMF4: if (!cstate->is_atm) bpf_error(cstate, "'oamf4' supported only on raw ATM"); /* OAM F4 type */ b0 = gen_atmfield_code_internal(cstate, A_VCI, 3, BPF_JEQ, 0); b1 = gen_atmfield_code_internal(cstate, A_VCI, 4, BPF_JEQ, 0); gen_or(b0, b1); b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0); gen_and(b0, b1); break; case A_CONNECTMSG: /* * Get Q.2931 signalling messages for switched * virtual connection */ if (!cstate->is_atm) bpf_error(cstate, "'connectmsg' supported only on raw ATM"); b0 = gen_msg_abbrev(cstate, A_SETUP); b1 = gen_msg_abbrev(cstate, A_CALLPROCEED); gen_or(b0, b1); b0 = gen_msg_abbrev(cstate, A_CONNECT); gen_or(b0, b1); b0 = gen_msg_abbrev(cstate, A_CONNECTACK); gen_or(b0, b1); b0 = gen_msg_abbrev(cstate, A_RELEASE); gen_or(b0, b1); b0 = gen_msg_abbrev(cstate, A_RELEASE_DONE); gen_or(b0, b1); b0 = gen_atmtype_sc(cstate); gen_and(b0, b1); break; case A_METACONNECT: if (!cstate->is_atm) bpf_error(cstate, "'metaconnect' supported only on raw ATM"); b0 = gen_msg_abbrev(cstate, A_SETUP); b1 = gen_msg_abbrev(cstate, A_CALLPROCEED); gen_or(b0, b1); b0 = gen_msg_abbrev(cstate, A_CONNECT); gen_or(b0, b1); b0 = gen_msg_abbrev(cstate, A_RELEASE); gen_or(b0, b1); b0 = gen_msg_abbrev(cstate, A_RELEASE_DONE); gen_or(b0, b1); b0 = gen_atmtype_metac(cstate); gen_and(b0, b1); break; default: abort(); } return b1; }