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v7.0.0
lib/libnetlink.c
1 583 строки
35 KB
Stephen Hemminger
genl: move print_policy into genl
21 ноя 2025, 19:16
21 ноя 2025, 19:16
69942d7
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/* SPDX-License-Identifier: GPL-2.0-or-later */ /* * libnetlink.c RTnetlink service routines. * * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> */ #include <stdio.h> #include <stdlib.h> #include <stdbool.h> #include <unistd.h> #include <fcntl.h> #include <net/if_arp.h> #include <sys/socket.h> #include <netinet/in.h> #include <string.h> #include <errno.h> #include <time.h> #include <sys/uio.h> #include <linux/fib_rules.h> #include <linux/if_addrlabel.h> #include <linux/if_bridge.h> #include <linux/nexthop.h> #include "libnetlink.h" #include "json_print.h" #include "utils.h" #ifndef __aligned #define __aligned(x) __attribute__((aligned(x))) #endif #ifndef SOL_NETLINK #define SOL_NETLINK 270 #endif #ifndef MIN #define MIN(a, b) ((a) < (b) ? (a) : (b)) #endif int rcvbuf = 1024 * 1024; #ifdef HAVE_LIBMNL #include <libmnl/libmnl.h> static const enum mnl_attr_data_type extack_policy[NLMSGERR_ATTR_MAX + 1] = { [NLMSGERR_ATTR_MSG] = MNL_TYPE_NUL_STRING, [NLMSGERR_ATTR_OFFS] = MNL_TYPE_U32, }; static int err_attr_cb(const struct nlattr *attr, void *data) { const struct nlattr **tb = data; uint16_t type; if (mnl_attr_type_valid(attr, NLMSGERR_ATTR_MAX) < 0) { fprintf(stderr, "Invalid extack attribute\n"); return MNL_CB_ERROR; } type = mnl_attr_get_type(attr); if (mnl_attr_validate(attr, extack_policy[type]) < 0) { fprintf(stderr, "extack attribute %d failed validation\n", type); return MNL_CB_ERROR; } tb[type] = attr; return MNL_CB_OK; } static void print_ext_ack_msg(bool is_err, const char *msg) { fprintf(stderr, "%s: %s", is_err ? "Error" : "Warning", msg); if (msg[strlen(msg) - 1] != '.') fprintf(stderr, "."); fprintf(stderr, "\n"); } /* dump netlink extended ack error message */ int nl_dump_ext_ack(const struct nlmsghdr *nlh, nl_ext_ack_fn_t errfn) { struct nlattr *tb[NLMSGERR_ATTR_MAX + 1] = {}; const struct nlmsgerr *err = mnl_nlmsg_get_payload(nlh); const struct nlmsghdr *err_nlh = NULL; unsigned int hlen = sizeof(*err); const char *msg = NULL; uint32_t off = 0; /* no TLVs, nothing to do here */ if (!(nlh->nlmsg_flags & NLM_F_ACK_TLVS)) return 0; /* if NLM_F_CAPPED is set then the inner err msg was capped */ if (!(nlh->nlmsg_flags & NLM_F_CAPPED)) hlen += mnl_nlmsg_get_payload_len(&err->msg); if (mnl_attr_parse(nlh, hlen, err_attr_cb, tb) != MNL_CB_OK) return 0; if (tb[NLMSGERR_ATTR_MSG]) msg = mnl_attr_get_str(tb[NLMSGERR_ATTR_MSG]); if (tb[NLMSGERR_ATTR_OFFS]) { off = mnl_attr_get_u32(tb[NLMSGERR_ATTR_OFFS]); if (off > nlh->nlmsg_len) { fprintf(stderr, "Invalid offset for NLMSGERR_ATTR_OFFS\n"); off = 0; } else if (!(nlh->nlmsg_flags & NLM_F_CAPPED)) err_nlh = &err->msg; } if (tb[NLMSGERR_ATTR_MISS_TYPE]) fprintf(stderr, "Missing required attribute type %u\n", mnl_attr_get_u32(tb[NLMSGERR_ATTR_MISS_TYPE])); if (errfn) return errfn(msg, off, err_nlh); if (msg && *msg != '\0') { bool is_err = !!err->error; print_ext_ack_msg(is_err, msg); return is_err ? 1 : 0; } return 0; } int nl_dump_ext_ack_done(const struct nlmsghdr *nlh, unsigned int offset, int error) { struct nlattr *tb[NLMSGERR_ATTR_MAX + 1] = {}; const char *msg = NULL; if (mnl_attr_parse(nlh, offset, err_attr_cb, tb) != MNL_CB_OK) return 0; if (tb[NLMSGERR_ATTR_MSG]) msg = mnl_attr_get_str(tb[NLMSGERR_ATTR_MSG]); if (msg && *msg != '\0') { bool is_err = !!error; print_ext_ack_msg(is_err, msg); return is_err ? 1 : 0; } return 0; } #else #warning "libmnl required for error support" /* No extended error ack without libmnl */ int nl_dump_ext_ack(const struct nlmsghdr *nlh, nl_ext_ack_fn_t errfn) { return 0; } int nl_dump_ext_ack_done(const struct nlmsghdr *nlh, unsigned int offset, int error) { return 0; } #endif /* Older kernels may not support strict dump and filtering */ void rtnl_set_strict_dump(struct rtnl_handle *rth) { int one = 1; if (setsockopt(rth->fd, SOL_NETLINK, NETLINK_GET_STRICT_CHK, &one, sizeof(one)) < 0) return; rth->flags |= RTNL_HANDLE_F_STRICT_CHK; } int rtnl_add_nl_group(struct rtnl_handle *rth, unsigned int group) { return setsockopt(rth->fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &group, sizeof(group)); } void rtnl_close(struct rtnl_handle *rth) { if (rth->fd >= 0) { close(rth->fd); rth->fd = -1; } } int rtnl_open_byproto(struct rtnl_handle *rth, unsigned int subscriptions, int protocol) { socklen_t addr_len; int sndbuf = 32768; int one = 1; memset(rth, 0, sizeof(*rth)); rth->proto = protocol; rth->fd = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, protocol); if (rth->fd < 0) { perror("Cannot open netlink socket"); return -1; } if (setsockopt(rth->fd, SOL_SOCKET, SO_SNDBUF, &sndbuf, sizeof(sndbuf)) < 0) { perror("SO_SNDBUF"); goto err; } if (setsockopt(rth->fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, sizeof(rcvbuf)) < 0) { perror("SO_RCVBUF"); goto err; } /* Older kernels may no support extended ACK reporting */ setsockopt(rth->fd, SOL_NETLINK, NETLINK_EXT_ACK, &one, sizeof(one)); memset(&rth->local, 0, sizeof(rth->local)); rth->local.nl_family = AF_NETLINK; rth->local.nl_groups = subscriptions; if (bind(rth->fd, (struct sockaddr *)&rth->local, sizeof(rth->local)) < 0) { perror("Cannot bind netlink socket"); goto err; } addr_len = sizeof(rth->local); if (getsockname(rth->fd, (struct sockaddr *)&rth->local, &addr_len) < 0) { perror("Cannot getsockname"); goto err; } if (addr_len != sizeof(rth->local)) { fprintf(stderr, "Wrong address length %d\n", addr_len); goto err; } if (rth->local.nl_family != AF_NETLINK) { fprintf(stderr, "Wrong address family %d\n", rth->local.nl_family); goto err; } rth->seq = time(NULL); return 0; err: rtnl_close(rth); return -1; } int rtnl_open(struct rtnl_handle *rth, unsigned int subscriptions) { return rtnl_open_byproto(rth, subscriptions, NETLINK_ROUTE); } int rtnl_nexthopdump_req(struct rtnl_handle *rth, int family, req_filter_fn_t filter_fn) { struct { struct nlmsghdr nlh; struct nhmsg nhm; char buf[128]; } req = { .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct nhmsg)), .nlh.nlmsg_type = RTM_GETNEXTHOP, .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, .nlh.nlmsg_seq = rth->dump = ++rth->seq, .nhm.nh_family = family, }; if (filter_fn) { int err; err = filter_fn(&req.nlh, sizeof(req)); if (err) return err; } return send(rth->fd, &req, sizeof(req), 0); } int rtnl_nexthop_bucket_dump_req(struct rtnl_handle *rth, int family, req_filter_fn_t filter_fn) { struct { struct nlmsghdr nlh; struct nhmsg nhm; char buf[128]; } req = { .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct nhmsg)), .nlh.nlmsg_type = RTM_GETNEXTHOPBUCKET, .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, .nlh.nlmsg_seq = rth->dump = ++rth->seq, .nhm.nh_family = family, }; if (filter_fn) { int err; err = filter_fn(&req.nlh, sizeof(req)); if (err) return err; } return send(rth->fd, &req, sizeof(req), 0); } int rtnl_addrdump_req(struct rtnl_handle *rth, int family, req_filter_fn_t filter_fn) { struct { struct nlmsghdr nlh; struct ifaddrmsg ifm; char buf[128]; } req = { .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg)), .nlh.nlmsg_type = RTM_GETADDR, .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, .nlh.nlmsg_seq = rth->dump = ++rth->seq, .ifm.ifa_family = family, }; if (filter_fn) { int err; err = filter_fn(&req.nlh, sizeof(req)); if (err) return err; } return send(rth->fd, &req, sizeof(req), 0); } int rtnl_addrlbldump_req(struct rtnl_handle *rth, int family) { struct { struct nlmsghdr nlh; struct ifaddrlblmsg ifal; } req = { .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrlblmsg)), .nlh.nlmsg_type = RTM_GETADDRLABEL, .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, .nlh.nlmsg_seq = rth->dump = ++rth->seq, .ifal.ifal_family = family, }; return send(rth->fd, &req, sizeof(req), 0); } int rtnl_routedump_req(struct rtnl_handle *rth, int family, req_filter_fn_t filter_fn) { struct { struct nlmsghdr nlh; struct rtmsg rtm; char buf[128]; } req = { .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg)), .nlh.nlmsg_type = RTM_GETROUTE, .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, .nlh.nlmsg_seq = rth->dump = ++rth->seq, .rtm.rtm_family = family, }; if (filter_fn) { int err; err = filter_fn(&req.nlh, sizeof(req)); if (err) return err; } return send(rth->fd, &req, sizeof(req), 0); } int rtnl_ruledump_req(struct rtnl_handle *rth, int family) { struct { struct nlmsghdr nlh; struct fib_rule_hdr frh; } req = { .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct fib_rule_hdr)), .nlh.nlmsg_type = RTM_GETRULE, .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, .nlh.nlmsg_seq = rth->dump = ++rth->seq, .frh.family = family }; return send(rth->fd, &req, sizeof(req), 0); } int rtnl_neighdump_req(struct rtnl_handle *rth, int family, req_filter_fn_t filter_fn) { struct { struct nlmsghdr nlh; struct ndmsg ndm; char buf[256]; } req = { .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ndmsg)), .nlh.nlmsg_type = RTM_GETNEIGH, .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, .nlh.nlmsg_seq = rth->dump = ++rth->seq, .ndm.ndm_family = family, }; if (filter_fn) { int err; err = filter_fn(&req.nlh, sizeof(req)); if (err) return err; } return send(rth->fd, &req, sizeof(req), 0); } int rtnl_neightbldump_req(struct rtnl_handle *rth, int family) { struct { struct nlmsghdr nlh; struct ndtmsg ndtmsg; } req = { .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ndtmsg)), .nlh.nlmsg_type = RTM_GETNEIGHTBL, .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, .nlh.nlmsg_seq = rth->dump = ++rth->seq, .ndtmsg.ndtm_family = family, }; return send(rth->fd, &req, sizeof(req), 0); } int rtnl_mdbdump_req(struct rtnl_handle *rth, int family) { struct { struct nlmsghdr nlh; struct br_port_msg bpm; } req = { .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct br_port_msg)), .nlh.nlmsg_type = RTM_GETMDB, .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, .nlh.nlmsg_seq = rth->dump = ++rth->seq, .bpm.family = family, }; return send(rth->fd, &req, sizeof(req), 0); } int rtnl_brvlandump_req(struct rtnl_handle *rth, int family, __u32 dump_flags) { struct { struct nlmsghdr nlh; struct br_vlan_msg bvm; char buf[256]; } req = { .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct br_vlan_msg)), .nlh.nlmsg_type = RTM_GETVLAN, .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, .nlh.nlmsg_seq = rth->dump = ++rth->seq, .bvm.family = family, }; addattr32(&req.nlh, sizeof(req), BRIDGE_VLANDB_DUMP_FLAGS, dump_flags); return send(rth->fd, &req, sizeof(req), 0); } int rtnl_netconfdump_req(struct rtnl_handle *rth, int family) { struct { struct nlmsghdr nlh; struct netconfmsg ncm; char buf[0] __aligned(NLMSG_ALIGNTO); } req = { .nlh.nlmsg_len = NLMSG_LENGTH(NLMSG_ALIGN(sizeof(struct netconfmsg))), .nlh.nlmsg_type = RTM_GETNETCONF, .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, .nlh.nlmsg_seq = rth->dump = ++rth->seq, .ncm.ncm_family = family, }; return send(rth->fd, &req, sizeof(req), 0); } int rtnl_nsiddump_req_filter_fn(struct rtnl_handle *rth, int family, req_filter_fn_t filter_fn) { struct { struct nlmsghdr nlh; struct rtgenmsg rtm; char buf[1024]; } req = { .nlh.nlmsg_len = NLMSG_LENGTH(NLMSG_ALIGN(sizeof(struct rtgenmsg))), .nlh.nlmsg_type = RTM_GETNSID, .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, .nlh.nlmsg_seq = rth->dump = ++rth->seq, .rtm.rtgen_family = family, }; int err; if (!filter_fn) return -EINVAL; err = filter_fn(&req.nlh, sizeof(req)); if (err) return err; return send(rth->fd, &req, req.nlh.nlmsg_len, 0); } static int __rtnl_linkdump_req(struct rtnl_handle *rth, int family) { struct { struct nlmsghdr nlh; struct ifinfomsg ifm; } req = { .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)), .nlh.nlmsg_type = RTM_GETLINK, .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, .nlh.nlmsg_seq = rth->dump = ++rth->seq, .ifm.ifi_family = family, }; return send(rth->fd, &req, sizeof(req), 0); } int rtnl_linkdump_req(struct rtnl_handle *rth, int family) { if (family == AF_UNSPEC) return rtnl_linkdump_req_filter(rth, family, RTEXT_FILTER_VF); return __rtnl_linkdump_req(rth, family); } int rtnl_linkdump_req_filter(struct rtnl_handle *rth, int family, __u32 filt_mask) { if (family == AF_UNSPEC || family == AF_BRIDGE) { struct { struct nlmsghdr nlh; struct ifinfomsg ifm; /* attribute has to be NLMSG aligned */ struct rtattr ext_req __aligned(NLMSG_ALIGNTO); __u32 ext_filter_mask; } req = { .nlh.nlmsg_len = sizeof(req), .nlh.nlmsg_type = RTM_GETLINK, .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, .nlh.nlmsg_seq = rth->dump = ++rth->seq, .ifm.ifi_family = family, .ext_req.rta_type = IFLA_EXT_MASK, .ext_req.rta_len = RTA_LENGTH(sizeof(__u32)), .ext_filter_mask = filt_mask, }; return send(rth->fd, &req, sizeof(req), 0); } return __rtnl_linkdump_req(rth, family); } int rtnl_linkdump_req_filter_fn(struct rtnl_handle *rth, int family, req_filter_fn_t filter_fn) { if (family == AF_UNSPEC || family == AF_PACKET) { struct { struct nlmsghdr nlh; struct ifinfomsg ifm; char buf[1024]; } req = { .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)), .nlh.nlmsg_type = RTM_GETLINK, .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, .nlh.nlmsg_seq = rth->dump = ++rth->seq, .ifm.ifi_family = family, }; int err; if (!filter_fn) return -EINVAL; err = filter_fn(&req.nlh, sizeof(req)); if (err) return err; return send(rth->fd, &req, req.nlh.nlmsg_len, 0); } return __rtnl_linkdump_req(rth, family); } int rtnl_fdb_linkdump_req_filter_fn(struct rtnl_handle *rth, req_filter_fn_t filter_fn) { struct { struct nlmsghdr nlh; struct ifinfomsg ifm; char buf[128]; } req = { .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)), .nlh.nlmsg_type = RTM_GETNEIGH, .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, .nlh.nlmsg_seq = rth->dump = ++rth->seq, .ifm.ifi_family = PF_BRIDGE, }; int err; err = filter_fn(&req.nlh, sizeof(req)); if (err) return err; return send(rth->fd, &req, sizeof(req), 0); } int rtnl_statsdump_req_filter(struct rtnl_handle *rth, int fam, __u32 filt_mask, int (*filter_fn)(struct ipstats_req *req, void *data), void *filter_data) { struct ipstats_req req; memset(&req, 0, sizeof(req)); req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct if_stats_msg)); req.nlh.nlmsg_type = RTM_GETSTATS; req.nlh.nlmsg_flags = NLM_F_DUMP|NLM_F_REQUEST; req.nlh.nlmsg_pid = 0; req.nlh.nlmsg_seq = rth->dump = ++rth->seq; req.ifsm.family = fam; req.ifsm.filter_mask = filt_mask; if (filter_fn) { int err; err = filter_fn(&req, filter_data); if (err) return err; } return send(rth->fd, &req, sizeof(req), 0); } int rtnl_send(struct rtnl_handle *rth, const void *buf, int len) { return send(rth->fd, buf, len, 0); } int rtnl_send_check(struct rtnl_handle *rth, const void *buf, int len) { struct nlmsghdr *h; int status; char resp[1024]; status = send(rth->fd, buf, len, 0); if (status < 0) return status; /* Check for immediate errors */ status = recv(rth->fd, resp, sizeof(resp), MSG_DONTWAIT|MSG_PEEK); if (status < 0) { if (errno == EAGAIN) return 0; return -1; } for (h = (struct nlmsghdr *)resp; NLMSG_OK(h, status); h = NLMSG_NEXT(h, status)) { if (h->nlmsg_type == NLMSG_ERROR) { struct nlmsgerr *err = (struct nlmsgerr *)NLMSG_DATA(h); if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) fprintf(stderr, "ERROR truncated\n"); else errno = -err->error; return -1; } } return 0; } int rtnl_dump_request(struct rtnl_handle *rth, int type, void *req, int len) { struct nlmsghdr nlh = { .nlmsg_len = NLMSG_LENGTH(len), .nlmsg_type = type, .nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, .nlmsg_seq = rth->dump = ++rth->seq, }; struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK }; struct iovec iov[2] = { { .iov_base = &nlh, .iov_len = sizeof(nlh) }, { .iov_base = req, .iov_len = len } }; struct msghdr msg = { .msg_name = &nladdr, .msg_namelen = sizeof(nladdr), .msg_iov = iov, .msg_iovlen = 2, }; return sendmsg(rth->fd, &msg, 0); } int rtnl_dump_request_n(struct rtnl_handle *rth, struct nlmsghdr *n) { struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK }; struct iovec iov = { .iov_base = n, .iov_len = n->nlmsg_len }; struct msghdr msg = { .msg_name = &nladdr, .msg_namelen = sizeof(nladdr), .msg_iov = &iov, .msg_iovlen = 1, }; n->nlmsg_flags = NLM_F_DUMP|NLM_F_REQUEST; n->nlmsg_pid = 0; n->nlmsg_seq = rth->dump = ++rth->seq; return sendmsg(rth->fd, &msg, 0); } static int rtnl_dump_done(struct nlmsghdr *h, const struct rtnl_dump_filter_arg *a) { int len; if (h->nlmsg_len < NLMSG_LENGTH(sizeof(int))) { fprintf(stderr, "DONE truncated\n"); return -1; } len = *(int *)NLMSG_DATA(h); if (len < 0) { errno = -len; if (a->errhndlr && (a->errhndlr(h, a->arg2) & RTNL_SUPPRESS_NLMSG_DONE_NLERR)) return 0; /* check for any messages returned from kernel */ if (nl_dump_ext_ack_done(h, sizeof(int), len)) return len; switch (errno) { case ENOENT: case EOPNOTSUPP: return -1; case EMSGSIZE: fprintf(stderr, "Error: Buffer too small for object.\n"); break; default: perror("RTNETLINK answers"); } return len; } /* check for any messages returned from kernel */ nl_dump_ext_ack(h, NULL); return 0; } static int rtnl_dump_error(const struct rtnl_handle *rth, struct nlmsghdr *h, const struct rtnl_dump_filter_arg *a) { if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) { fprintf(stderr, "ERROR truncated\n"); } else { const struct nlmsgerr *err = (struct nlmsgerr *)NLMSG_DATA(h); errno = -err->error; if (rth->proto == NETLINK_SOCK_DIAG && (errno == ENOENT || errno == EOPNOTSUPP)) return -1; if (a->errhndlr && (a->errhndlr(h, a->arg2) & RTNL_SUPPRESS_NLMSG_ERROR_NLERR)) return 0; if (!(rth->flags & RTNL_HANDLE_F_SUPPRESS_NLERR)) perror("RTNETLINK answers"); } return -1; } static int __rtnl_recvmsg(int fd, struct msghdr *msg, int flags) { int len; do { len = recvmsg(fd, msg, flags); } while (len < 0 && (errno == EINTR || errno == EAGAIN)); if (len < 0) { fprintf(stderr, "netlink receive error %s (%d)\n", strerror(errno), errno); return -errno; } if (len == 0) { fprintf(stderr, "EOF on netlink\n"); return -ENODATA; } return len; } static int rtnl_recvmsg(int fd, struct msghdr *msg, char **answer) { struct iovec *iov = msg->msg_iov; char *buf; int len; iov->iov_base = NULL; iov->iov_len = 0; len = __rtnl_recvmsg(fd, msg, MSG_PEEK | MSG_TRUNC); if (len < 0) return len; if (len < 32768) len = 32768; buf = malloc(len); if (!buf) { fprintf(stderr, "malloc error: not enough buffer\n"); return -ENOMEM; } iov->iov_base = buf; iov->iov_len = len; len = __rtnl_recvmsg(fd, msg, 0); if (len < 0) { free(buf); return len; } if (answer) *answer = buf; else free(buf); return len; } static int rtnl_dump_filter_l(struct rtnl_handle *rth, const struct rtnl_dump_filter_arg *arg) { struct sockaddr_nl nladdr; struct iovec iov; struct msghdr msg = { .msg_name = &nladdr, .msg_namelen = sizeof(nladdr), .msg_iov = &iov, .msg_iovlen = 1, }; char *buf; int dump_intr = 0; while (1) { int status; const struct rtnl_dump_filter_arg *a; int found_done = 0; int msglen = 0; status = rtnl_recvmsg(rth->fd, &msg, &buf); if (status < 0) return status; if (rth->dump_fp) fwrite(buf, 1, NLMSG_ALIGN(status), rth->dump_fp); for (a = arg; a->filter; a++) { struct nlmsghdr *h = (struct nlmsghdr *)buf; msglen = status; while (NLMSG_OK(h, msglen)) { int err = 0; h->nlmsg_flags &= ~a->nc_flags; if (nladdr.nl_pid != 0 || h->nlmsg_pid != rth->local.nl_pid || h->nlmsg_seq != rth->dump) goto skip_it; if (h->nlmsg_flags & NLM_F_DUMP_INTR) dump_intr = 1; if (h->nlmsg_type == NLMSG_DONE) { err = rtnl_dump_done(h, a); if (err < 0) { free(buf); return -1; } found_done = 1; break; /* process next filter */ } if (h->nlmsg_type == NLMSG_ERROR) { err = rtnl_dump_error(rth, h, a); if (err < 0) { free(buf); return -1; } goto skip_it; } if (!rth->dump_fp) { err = a->filter(h, a->arg1); if (err < 0) { free(buf); return err; } } skip_it: h = NLMSG_NEXT(h, msglen); } } free(buf); if (found_done) { if (dump_intr) fprintf(stderr, "Dump was interrupted and may be inconsistent.\n"); return 0; } if (msg.msg_flags & MSG_TRUNC) { fprintf(stderr, "Message truncated\n"); continue; } if (msglen) { fprintf(stderr, "!!!Remnant of size %d\n", msglen); exit(1); } } } int rtnl_dump_filter_nc(struct rtnl_handle *rth, rtnl_filter_t filter, void *arg1, __u16 nc_flags) { const struct rtnl_dump_filter_arg a[] = { { .filter = filter, .arg1 = arg1, .nc_flags = nc_flags, }, { }, }; return rtnl_dump_filter_l(rth, a); } int rtnl_dump_filter_errhndlr_nc(struct rtnl_handle *rth, rtnl_filter_t filter, void *arg1, rtnl_err_hndlr_t errhndlr, void *arg2, __u16 nc_flags) { const struct rtnl_dump_filter_arg a[] = { { .filter = filter, .arg1 = arg1, .errhndlr = errhndlr, .arg2 = arg2, .nc_flags = nc_flags, }, { }, }; return rtnl_dump_filter_l(rth, a); } static void rtnl_talk_error(struct nlmsghdr *h, struct nlmsgerr *err, nl_ext_ack_fn_t errfn) { if (nl_dump_ext_ack(h, errfn)) return; fprintf(stderr, "RTNETLINK answers: %s\n", strerror(-err->error)); } static int __rtnl_talk_iov(struct rtnl_handle *rtnl, struct iovec *iov, size_t iovlen, struct nlmsghdr **answer, bool show_rtnl_err, nl_ext_ack_fn_t errfn) { struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK }; struct iovec riov; struct msghdr msg = { .msg_name = &nladdr, .msg_namelen = sizeof(nladdr), .msg_iov = iov, .msg_iovlen = iovlen, }; unsigned int seq = 0; struct nlmsghdr *h; int i, status; char *buf; for (i = 0; i < iovlen; i++) { h = iov[i].iov_base; h->nlmsg_seq = seq = ++rtnl->seq; if (answer == NULL) h->nlmsg_flags |= NLM_F_ACK; } status = sendmsg(rtnl->fd, &msg, 0); if (status < 0) { perror("Cannot talk to rtnetlink"); return -1; } /* change msg to use the response iov */ msg.msg_iov = &riov; msg.msg_iovlen = 1; i = 0; while (1) { next: status = rtnl_recvmsg(rtnl->fd, &msg, &buf); ++i; if (status < 0) return status; if (msg.msg_namelen != sizeof(nladdr)) { fprintf(stderr, "sender address length == %d\n", msg.msg_namelen); exit(1); } for (h = (struct nlmsghdr *)buf; status >= sizeof(*h); ) { int len = h->nlmsg_len; int l = len - sizeof(*h); if (l < 0 || len > status) { if (msg.msg_flags & MSG_TRUNC) { fprintf(stderr, "Truncated message\n"); free(buf); return -1; } fprintf(stderr, "!!!malformed message: len=%d\n", len); exit(1); } if (nladdr.nl_pid != 0 || h->nlmsg_pid != rtnl->local.nl_pid || h->nlmsg_seq > seq || h->nlmsg_seq < seq - iovlen) { /* Don't forget to skip that message. */ status -= NLMSG_ALIGN(len); h = (struct nlmsghdr *)((char *)h + NLMSG_ALIGN(len)); continue; } if (h->nlmsg_type == NLMSG_ERROR) { struct nlmsgerr *err = (struct nlmsgerr *)NLMSG_DATA(h); int error = err->error; if (l < sizeof(struct nlmsgerr)) { fprintf(stderr, "ERROR truncated\n"); free(buf); return -1; } if (!error) { /* check messages from kernel */ nl_dump_ext_ack(h, errfn); } else { errno = -error; if (rtnl->proto != NETLINK_SOCK_DIAG && show_rtnl_err) rtnl_talk_error(h, err, errfn); } if (i < iovlen) { free(buf); goto next; } if (error) { free(buf); return -i; } if (answer) *answer = (struct nlmsghdr *)buf; else free(buf); return 0; } if (answer) { *answer = (struct nlmsghdr *)buf; return 0; } fprintf(stderr, "Unexpected reply!!!\n"); status -= NLMSG_ALIGN(len); h = (struct nlmsghdr *)((char *)h + NLMSG_ALIGN(len)); } free(buf); if (msg.msg_flags & MSG_TRUNC) { fprintf(stderr, "Message truncated\n"); continue; } if (status) { fprintf(stderr, "!!!Remnant of size %d\n", status); exit(1); } } } static int __rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, struct nlmsghdr **answer, bool show_rtnl_err, nl_ext_ack_fn_t errfn) { struct iovec iov = { .iov_base = n, .iov_len = n->nlmsg_len }; return __rtnl_talk_iov(rtnl, &iov, 1, answer, show_rtnl_err, errfn); } int rtnl_echo_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, int use_json, int (*print_info)(struct nlmsghdr *n, void *arg)) { struct nlmsghdr *answer; int ret; n->nlmsg_flags |= NLM_F_ECHO | NLM_F_ACK; ret = rtnl_talk(rtnl, n, &answer); if (ret) return ret; new_json_obj(use_json); open_json_object(NULL); print_info(answer, stdout); close_json_object(); delete_json_obj(); free(answer); return 0; } int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, struct nlmsghdr **answer) { return __rtnl_talk(rtnl, n, answer, true, NULL); } int rtnl_talk_suppress_rtnl_errmsg(struct rtnl_handle *rtnl, struct nlmsghdr *n, struct nlmsghdr **answer) { return __rtnl_talk(rtnl, n, answer, false, NULL); } int rtnl_listen_all_nsid(struct rtnl_handle *rth) { unsigned int on = 1; if (setsockopt(rth->fd, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, &on, sizeof(on)) < 0) { perror("NETLINK_LISTEN_ALL_NSID"); return -1; } rth->flags |= RTNL_HANDLE_F_LISTEN_ALL_NSID; return 0; } int rtnl_listen(struct rtnl_handle *rtnl, rtnl_listen_filter_t handler, void *jarg) { int status; struct nlmsghdr *h; struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK }; struct iovec iov; struct msghdr msg = { .msg_name = &nladdr, .msg_namelen = sizeof(nladdr), .msg_iov = &iov, .msg_iovlen = 1, }; char buf[16384]; char cmsgbuf[BUFSIZ]; iov.iov_base = buf; while (1) { struct rtnl_ctrl_data ctrl; struct cmsghdr *cmsg; if (rtnl->flags & RTNL_HANDLE_F_LISTEN_ALL_NSID) { msg.msg_control = &cmsgbuf; msg.msg_controllen = sizeof(cmsgbuf); } iov.iov_len = sizeof(buf); status = recvmsg(rtnl->fd, &msg, 0); if (status < 0) { if (errno == EINTR || errno == EAGAIN) continue; fprintf(stderr, "netlink receive error %s (%d)\n", strerror(errno), errno); if (errno == ENOBUFS) continue; return -1; } if (status == 0) { fprintf(stderr, "EOF on netlink\n"); return -1; } if (msg.msg_namelen != sizeof(nladdr)) { fprintf(stderr, "Sender address length == %d\n", msg.msg_namelen); exit(1); } if (rtnl->flags & RTNL_HANDLE_F_LISTEN_ALL_NSID) { memset(&ctrl, 0, sizeof(ctrl)); ctrl.nsid = -1; for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) if (cmsg->cmsg_level == SOL_NETLINK && cmsg->cmsg_type == NETLINK_LISTEN_ALL_NSID && cmsg->cmsg_len == CMSG_LEN(sizeof(int))) { int *data = (int *)CMSG_DATA(cmsg); ctrl.nsid = *data; } } for (h = (struct nlmsghdr *)buf; status >= sizeof(*h); ) { int err; int len = h->nlmsg_len; int l = len - sizeof(*h); if (l < 0 || len > status) { if (msg.msg_flags & MSG_TRUNC) { fprintf(stderr, "Truncated message\n"); return -1; } fprintf(stderr, "!!!malformed message: len=%d\n", len); exit(1); } err = handler(&ctrl, h, jarg); if (err < 0) return err; status -= NLMSG_ALIGN(len); h = (struct nlmsghdr *)((char *)h + NLMSG_ALIGN(len)); } if (msg.msg_flags & MSG_TRUNC) { fprintf(stderr, "Message truncated\n"); continue; } if (status) { fprintf(stderr, "!!!Remnant of size %d\n", status); exit(1); } } } int rtnl_from_file(FILE *rtnl, rtnl_listen_filter_t handler, void *jarg) { size_t status; char buf[16384]; struct nlmsghdr *h = (struct nlmsghdr *)buf; while (1) { int err, len; int l; status = fread(&buf, 1, sizeof(*h), rtnl); if (status == 0 && feof(rtnl)) return 0; if (status != sizeof(*h)) { if (ferror(rtnl)) perror("rtnl_from_file: fread"); if (feof(rtnl)) fprintf(stderr, "rtnl-from_file: truncated message\n"); return -1; } len = h->nlmsg_len; l = len - sizeof(*h); if (l < 0 || len > sizeof(buf)) { fprintf(stderr, "!!!malformed message: len=%d @%lu\n", len, ftell(rtnl)); return -1; } status = fread(NLMSG_DATA(h), 1, NLMSG_ALIGN(l), rtnl); if (status != NLMSG_ALIGN(l)) { if (ferror(rtnl)) perror("rtnl_from_file: fread"); if (feof(rtnl)) fprintf(stderr, "rtnl-from_file: truncated message\n"); return -1; } err = handler(NULL, h, jarg); if (err < 0) return err; } } int addattr(struct nlmsghdr *n, int maxlen, int type) { return addattr_l(n, maxlen, type, NULL, 0); } int addattr8(struct nlmsghdr *n, int maxlen, int type, __u8 data) { return addattr_l(n, maxlen, type, &data, sizeof(__u8)); } int addattr16(struct nlmsghdr *n, int maxlen, int type, __u16 data) { return addattr_l(n, maxlen, type, &data, sizeof(__u16)); } int addattr32(struct nlmsghdr *n, int maxlen, int type, __u32 data) { return addattr_l(n, maxlen, type, &data, sizeof(__u32)); } int addattr64(struct nlmsghdr *n, int maxlen, int type, __u64 data) { return addattr_l(n, maxlen, type, &data, sizeof(__u64)); } int addattrstrz(struct nlmsghdr *n, int maxlen, int type, const char *str) { return addattr_l(n, maxlen, type, str, strlen(str)+1); } int addattr_l(struct nlmsghdr *n, int maxlen, int type, const void *data, int alen) { int len = RTA_LENGTH(alen); struct rtattr *rta; if (NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len) > maxlen) { fprintf(stderr, "addattr_l ERROR: message exceeded bound of %d\n", maxlen); return -1; } rta = NLMSG_TAIL(n); rta->rta_type = type; rta->rta_len = len; if (alen) memcpy(RTA_DATA(rta), data, alen); n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len); return 0; } int addraw_l(struct nlmsghdr *n, int maxlen, const void *data, int len) { if (NLMSG_ALIGN(n->nlmsg_len) + NLMSG_ALIGN(len) > maxlen) { fprintf(stderr, "addraw_l ERROR: message exceeded bound of %d\n", maxlen); return -1; } memcpy(NLMSG_TAIL(n), data, len); memset((void *) NLMSG_TAIL(n) + len, 0, NLMSG_ALIGN(len) - len); n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + NLMSG_ALIGN(len); return 0; } struct rtattr *addattr_nest(struct nlmsghdr *n, int maxlen, int type) { struct rtattr *nest = NLMSG_TAIL(n); addattr_l(n, maxlen, type, NULL, 0); return nest; } int addattr_nest_end(struct nlmsghdr *n, struct rtattr *nest) { nest->rta_len = (void *)NLMSG_TAIL(n) - (void *)nest; return n->nlmsg_len; } struct rtattr *addattr_nest_compat(struct nlmsghdr *n, int maxlen, int type, const void *data, int len) { struct rtattr *start = NLMSG_TAIL(n); addattr_l(n, maxlen, type, data, len); addattr_nest(n, maxlen, type); return start; } int addattr_nest_compat_end(struct nlmsghdr *n, struct rtattr *start) { struct rtattr *nest = (void *)start + NLMSG_ALIGN(start->rta_len); start->rta_len = (void *)NLMSG_TAIL(n) - (void *)start; addattr_nest_end(n, nest); return n->nlmsg_len; } int rta_addattr32(struct rtattr *rta, int maxlen, int type, __u32 data) { int len = RTA_LENGTH(4); struct rtattr *subrta; if (RTA_ALIGN(rta->rta_len) + len > maxlen) { fprintf(stderr, "rta_addattr32: Error! max allowed bound %d exceeded\n", maxlen); return -1; } subrta = (struct rtattr *)(((char *)rta) + RTA_ALIGN(rta->rta_len)); subrta->rta_type = type; subrta->rta_len = len; memcpy(RTA_DATA(subrta), &data, 4); rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len; return 0; } int rta_addattr_l(struct rtattr *rta, int maxlen, int type, const void *data, int alen) { struct rtattr *subrta; int len = RTA_LENGTH(alen); if (RTA_ALIGN(rta->rta_len) + RTA_ALIGN(len) > maxlen) { fprintf(stderr, "rta_addattr_l: Error! max allowed bound %d exceeded\n", maxlen); return -1; } subrta = (struct rtattr *)(((char *)rta) + RTA_ALIGN(rta->rta_len)); subrta->rta_type = type; subrta->rta_len = len; if (alen) memcpy(RTA_DATA(subrta), data, alen); rta->rta_len = NLMSG_ALIGN(rta->rta_len) + RTA_ALIGN(len); return 0; } int rta_addattr8(struct rtattr *rta, int maxlen, int type, __u8 data) { return rta_addattr_l(rta, maxlen, type, &data, sizeof(__u8)); } int rta_addattr16(struct rtattr *rta, int maxlen, int type, __u16 data) { return rta_addattr_l(rta, maxlen, type, &data, sizeof(__u16)); } int rta_addattr64(struct rtattr *rta, int maxlen, int type, __u64 data) { return rta_addattr_l(rta, maxlen, type, &data, sizeof(__u64)); } struct rtattr *rta_nest(struct rtattr *rta, int maxlen, int type) { struct rtattr *nest = RTA_TAIL(rta); rta_addattr_l(rta, maxlen, type, NULL, 0); nest->rta_type |= NLA_F_NESTED; return nest; } int rta_nest_end(struct rtattr *rta, struct rtattr *nest) { nest->rta_len = (void *)RTA_TAIL(rta) - (void *)nest; return rta->rta_len; } int parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len) { return parse_rtattr_flags(tb, max, rta, len, 0); } int parse_rtattr_flags(struct rtattr *tb[], int max, struct rtattr *rta, int len, unsigned short flags) { unsigned short type; memset(tb, 0, sizeof(struct rtattr *) * (max + 1)); while (RTA_OK(rta, len)) { type = rta->rta_type & ~flags; if ((type <= max) && (!tb[type])) tb[type] = rta; rta = RTA_NEXT(rta, len); } if (len) fprintf(stderr, "!!!Deficit %d, rta_len=%d\n", len, rta->rta_len); return 0; } struct rtattr *parse_rtattr_one(int type, struct rtattr *rta, int len) { while (RTA_OK(rta, len)) { if (rta->rta_type == type) return rta; rta = RTA_NEXT(rta, len); } if (len) fprintf(stderr, "!!!Deficit %d, rta_len=%d\n", len, rta->rta_len); return NULL; } int __parse_rtattr_nested_compat(struct rtattr *tb[], int max, struct rtattr *rta, int len) { if (RTA_PAYLOAD(rta) < len) return -1; if (RTA_PAYLOAD(rta) >= RTA_ALIGN(len) + sizeof(struct rtattr)) { rta = RTA_DATA(rta) + RTA_ALIGN(len); return parse_rtattr_nested(tb, max, rta); } memset(tb, 0, sizeof(struct rtattr *) * (max + 1)); return 0; } int rtnl_tunneldump_req(struct rtnl_handle *rth, int family, int ifindex, __u8 flags) { struct { struct nlmsghdr nlh; struct tunnel_msg tmsg; char buf[256]; } req = { .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tunnel_msg)), .nlh.nlmsg_type = RTM_GETTUNNEL, .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, .nlh.nlmsg_seq = rth->dump = ++rth->seq, .tmsg.family = family, .tmsg.flags = flags, .tmsg.ifindex = ifindex, }; return send(rth->fd, &req, sizeof(req), 0); }