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v261
src/basic/socket-util.c
1 891 строка
59 KB
Chitoku
vsock-util: allow VMADDR_CID_ANY as local CID if enabled in hwdb
13 июн 2026, 16:54
13 июн 2026, 16:54
85afe8e
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/* SPDX-License-Identifier: LGPL-2.1-or-later */ #include <fcntl.h> #include <linux/if.h> #include <linux/if_arp.h> #include <linux/if_ether.h> #include <linux/if_infiniband.h> #include <linux/pkt_sched.h> #include <mqueue.h> #include <net/if.h> #include <netdb.h> #include <netinet/ip.h> #include <poll.h> #include <stdio.h> #include <sys/ioctl.h> #include <unistd.h> #include "alloc-util.h" #include "errno-util.h" #include "escape.h" #include "fd-util.h" #include "format-ifname.h" #include "format-util.h" #include "in-addr-util.h" #include "io-util.h" #include "log.h" #include "memory-util.h" #include "parse-util.h" #include "path-util.h" #include "pidref.h" #include "process-util.h" #include "random-util.h" #include "socket-util.h" #include "sparse-endian.h" #include "string-table.h" #include "string-util.h" #include "strv.h" #include "sysctl-util.h" #if ENABLE_IDN # define IDN_FLAGS NI_IDN #else # define IDN_FLAGS 0 #endif static const char* const socket_address_type_table[] = { [SOCK_STREAM] = "Stream", [SOCK_DGRAM] = "Datagram", [SOCK_RAW] = "Raw", [SOCK_RDM] = "ReliableDatagram", [SOCK_SEQPACKET] = "SequentialPacket", [SOCK_DCCP] = "DatagramCongestionControl", }; DEFINE_STRING_TABLE_LOOKUP(socket_address_type, int); int socket_address_verify(const SocketAddress *a, bool strict) { assert(a); /* With 'strict' we enforce additional sanity constraints which are not set by the standard, * but should only apply to sockets we create ourselves. */ switch (socket_address_family(a)) { case AF_INET: if (a->size != sizeof(struct sockaddr_in)) return -EINVAL; if (a->sockaddr.in.sin_port == 0) return -EINVAL; if (!IN_SET(a->type, 0, SOCK_STREAM, SOCK_DGRAM)) return -EINVAL; return 0; case AF_INET6: if (a->size != sizeof(struct sockaddr_in6)) return -EINVAL; if (a->sockaddr.in6.sin6_port == 0) return -EINVAL; if (!IN_SET(a->type, 0, SOCK_STREAM, SOCK_DGRAM)) return -EINVAL; return 0; case AF_UNIX: if (a->size < offsetof(struct sockaddr_un, sun_path)) return -EINVAL; if (a->size > sizeof(struct sockaddr_un) + !strict) /* If !strict, allow one extra byte, since getsockname() on Linux will append * a NUL byte if we have path sockets that are above sun_path's full size. */ return -EINVAL; if (a->size > offsetof(struct sockaddr_un, sun_path) && a->sockaddr.un.sun_path[0] != 0 && strict) { /* Only validate file system sockets here, and only in strict mode */ const char *e; e = memchr(a->sockaddr.un.sun_path, 0, sizeof(a->sockaddr.un.sun_path)); if (e) { /* If there's an embedded NUL byte, make sure the size of the socket address matches it */ if (a->size != offsetof(struct sockaddr_un, sun_path) + (e - a->sockaddr.un.sun_path) + 1) return -EINVAL; } else { /* If there's no embedded NUL byte, then the size needs to match the whole * structure or the structure with one extra NUL byte suffixed. (Yeah, Linux is awful, * and considers both equivalent: getsockname() even extends sockaddr_un beyond its * size if the path is non NUL terminated.) */ if (!IN_SET(a->size, sizeof(a->sockaddr.un.sun_path), sizeof(a->sockaddr.un.sun_path)+1)) return -EINVAL; } } if (!IN_SET(a->type, 0, SOCK_STREAM, SOCK_DGRAM, SOCK_SEQPACKET)) return -EINVAL; return 0; case AF_NETLINK: if (a->size != sizeof(struct sockaddr_nl)) return -EINVAL; if (!IN_SET(a->type, 0, SOCK_RAW, SOCK_DGRAM)) return -EINVAL; return 0; case AF_VSOCK: if (a->size != sizeof(struct sockaddr_vm)) return -EINVAL; if (!IN_SET(a->type, 0, SOCK_STREAM, SOCK_DGRAM)) return -EINVAL; return 0; default: return -EAFNOSUPPORT; } } int socket_address_print(const SocketAddress *a, char **ret) { int r; assert(a); assert(ret); r = socket_address_verify(a, false); /* We do non-strict validation, because we want to be * able to pretty-print any socket the kernel considers * valid. We still need to do validation to know if we * can meaningfully print the address. */ if (r < 0) return r; if (socket_address_family(a) == AF_NETLINK) { _cleanup_free_ char *sfamily = NULL; r = netlink_family_to_string_alloc(a->protocol, &sfamily); if (r < 0) return r; r = asprintf(ret, "%s %u", sfamily, a->sockaddr.nl.nl_groups); if (r < 0) return -ENOMEM; return 0; } return sockaddr_pretty(&a->sockaddr.sa, a->size, false, true, ret); } bool socket_address_can_accept(const SocketAddress *a) { assert(a); return IN_SET(a->type, SOCK_STREAM, SOCK_SEQPACKET); } bool socket_address_equal(const SocketAddress *a, const SocketAddress *b) { assert(a); assert(b); /* Invalid addresses are unequal to all */ if (socket_address_verify(a, false) < 0 || socket_address_verify(b, false) < 0) return false; if (a->type != b->type) return false; if (socket_address_family(a) != socket_address_family(b)) return false; switch (socket_address_family(a)) { case AF_INET: if (a->sockaddr.in.sin_addr.s_addr != b->sockaddr.in.sin_addr.s_addr) return false; if (a->sockaddr.in.sin_port != b->sockaddr.in.sin_port) return false; break; case AF_INET6: if (memcmp(&a->sockaddr.in6.sin6_addr, &b->sockaddr.in6.sin6_addr, sizeof(a->sockaddr.in6.sin6_addr)) != 0) return false; if (a->sockaddr.in6.sin6_port != b->sockaddr.in6.sin6_port) return false; break; case AF_UNIX: if (a->size <= offsetof(struct sockaddr_un, sun_path) || b->size <= offsetof(struct sockaddr_un, sun_path)) return false; if ((a->sockaddr.un.sun_path[0] == 0) != (b->sockaddr.un.sun_path[0] == 0)) return false; if (a->sockaddr.un.sun_path[0]) { if (!path_equal_or_inode_same(a->sockaddr.un.sun_path, b->sockaddr.un.sun_path, 0)) return false; } else { if (a->size != b->size) return false; if (memcmp(a->sockaddr.un.sun_path, b->sockaddr.un.sun_path, a->size) != 0) return false; } break; case AF_NETLINK: if (a->protocol != b->protocol) return false; if (a->sockaddr.nl.nl_groups != b->sockaddr.nl.nl_groups) return false; break; case AF_VSOCK: if (a->sockaddr.vm.svm_cid != b->sockaddr.vm.svm_cid) return false; if (a->sockaddr.vm.svm_port != b->sockaddr.vm.svm_port) return false; break; default: /* Cannot compare, so we assume the addresses are different */ return false; } return true; } const char* socket_address_get_path(const SocketAddress *a) { assert(a); if (socket_address_family(a) != AF_UNIX) return NULL; if (a->sockaddr.un.sun_path[0] == 0) return NULL; /* Note that this is only safe because we know that there's an extra NUL byte after the sockaddr_un * structure. On Linux AF_UNIX file system socket addresses don't have to be NUL terminated if they take up the * full sun_path space. */ assert_cc(sizeof(union sockaddr_union) >= sizeof(struct sockaddr_un)+1); return a->sockaddr.un.sun_path; } bool socket_ipv6_is_supported(void) { static int cached = -1; if (cached < 0) { if (access("/proc/net/if_inet6", F_OK) < 0) { if (errno != ENOENT) { log_debug_errno(errno, "Unexpected error when checking whether /proc/net/if_inet6 exists: %m"); return false; } cached = false; } else cached = true; } return cached; } bool socket_ipv6_is_enabled(void) { _cleanup_free_ char *v = NULL; int r; /* Much like socket_ipv6_is_supported(), but also checks that the sysctl that disables IPv6 on all * interfaces isn't turned on */ if (!socket_ipv6_is_supported()) return false; r = sysctl_read_ip_property(AF_INET6, "all", "disable_ipv6", &v); if (r < 0) { log_debug_errno(r, "Unexpected error reading 'net.ipv6.conf.all.disable_ipv6' sysctl: %m"); return true; } r = parse_boolean(v); if (r < 0) { log_debug_errno(r, "Failed to pare 'net.ipv6.conf.all.disable_ipv6' sysctl: %m"); return true; } return !r; } bool socket_address_matches_fd(const SocketAddress *a, int fd) { SocketAddress b; socklen_t solen; assert(a); assert(fd >= 0); b.size = sizeof(b.sockaddr); if (getsockname(fd, &b.sockaddr.sa, &b.size) < 0) return false; if (b.sockaddr.sa.sa_family != a->sockaddr.sa.sa_family) return false; solen = sizeof(b.type); if (getsockopt(fd, SOL_SOCKET, SO_TYPE, &b.type, &solen) < 0) return false; if (b.type != a->type) return false; if (a->protocol != 0) { solen = sizeof(b.protocol); if (getsockopt(fd, SOL_SOCKET, SO_PROTOCOL, &b.protocol, &solen) < 0) return false; if (b.protocol != a->protocol) return false; } return socket_address_equal(a, &b); } int sockaddr_port(const struct sockaddr *_sa, unsigned *ret_port) { const union sockaddr_union *sa = (const union sockaddr_union*) _sa; /* Note, this returns the port as 'unsigned' rather than 'uint16_t', as AF_VSOCK knows larger ports */ assert(sa); assert(ret_port); switch (sa->sa.sa_family) { case AF_INET: *ret_port = be16toh(sa->in.sin_port); return 0; case AF_INET6: *ret_port = be16toh(sa->in6.sin6_port); return 0; case AF_VSOCK: *ret_port = sa->vm.svm_port; return 0; default: return -EAFNOSUPPORT; } } const union in_addr_union *sockaddr_in_addr(const struct sockaddr *_sa) { const union sockaddr_union *sa = (const union sockaddr_union*) _sa; if (!sa) return NULL; switch (sa->sa.sa_family) { case AF_INET: return (const union in_addr_union*) &sa->in.sin_addr; case AF_INET6: return (const union in_addr_union*) &sa->in6.sin6_addr; default: return NULL; } } int sockaddr_set_in_addr( union sockaddr_union *u, int family, const union in_addr_union *a, uint16_t port) { assert(u); assert(a); switch (family) { case AF_INET: u->in = (struct sockaddr_in) { .sin_family = AF_INET, .sin_addr = a->in, .sin_port = htobe16(port), }; return 0; case AF_INET6: u->in6 = (struct sockaddr_in6) { .sin6_family = AF_INET6, .sin6_addr = a->in6, .sin6_port = htobe16(port), }; return 0; default: return -EAFNOSUPPORT; } } int sockaddr_pretty( const struct sockaddr *_sa, socklen_t salen, bool translate_ipv6, bool include_port, char **ret) { union sockaddr_union *sa = (union sockaddr_union*) _sa; char *p; int r; assert(sa); assert(salen >= sizeof(sa->sa.sa_family)); assert(ret); switch (sa->sa.sa_family) { case AF_INET: { uint32_t a; a = be32toh(sa->in.sin_addr.s_addr); if (include_port) r = asprintf(&p, "%u.%u.%u.%u:%u", a >> 24, (a >> 16) & 0xFF, (a >> 8) & 0xFF, a & 0xFF, be16toh(sa->in.sin_port)); else r = asprintf(&p, "%u.%u.%u.%u", a >> 24, (a >> 16) & 0xFF, (a >> 8) & 0xFF, a & 0xFF); if (r < 0) return -ENOMEM; break; } case AF_INET6: { static const unsigned char ipv4_prefix[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF }; if (translate_ipv6 && memcmp(&sa->in6.sin6_addr, ipv4_prefix, sizeof(ipv4_prefix)) == 0) { const uint8_t *a = sa->in6.sin6_addr.s6_addr+12; if (include_port) r = asprintf(&p, "%u.%u.%u.%u:%u", a[0], a[1], a[2], a[3], be16toh(sa->in6.sin6_port)); else r = asprintf(&p, "%u.%u.%u.%u", a[0], a[1], a[2], a[3]); if (r < 0) return -ENOMEM; } else { const char *a = IN6_ADDR_TO_STRING(&sa->in6.sin6_addr); if (include_port) { if (asprintf(&p, "[%s]:%u%s%s", a, be16toh(sa->in6.sin6_port), sa->in6.sin6_scope_id != 0 ? "%" : "", FORMAT_IFNAME_FULL(sa->in6.sin6_scope_id, FORMAT_IFNAME_IFINDEX)) < 0) return -ENOMEM; } else { if (sa->in6.sin6_scope_id != 0) p = strjoin(a, "%", FORMAT_IFNAME_FULL(sa->in6.sin6_scope_id, FORMAT_IFNAME_IFINDEX)); else p = strdup(a); if (!p) return -ENOMEM; } } break; } case AF_UNIX: if (salen <= offsetof(struct sockaddr_un, sun_path) || (sa->un.sun_path[0] == 0 && salen == offsetof(struct sockaddr_un, sun_path) + 1)) /* The name must have at least one character (and the leading NUL does not count) */ p = strdup("<unnamed>"); else { /* Note that we calculate the path pointer here through the .un_buffer[] field, in order to * outtrick bounds checking tools such as ubsan, which are too smart for their own good: on * Linux the kernel may return sun_path[] data one byte longer than the declared size of the * field. */ char *path = (char*) sa->un_buffer + offsetof(struct sockaddr_un, sun_path); size_t path_len = salen - offsetof(struct sockaddr_un, sun_path); if (path[0] == 0) { /* Abstract socket. When parsing address information from, we * explicitly reject overly long paths and paths with embedded NULs. * But we might get such a socket from the outside. Let's return * something meaningful and printable in this case. */ _cleanup_free_ char *e = NULL; e = cescape_length(path + 1, path_len - 1); if (!e) return -ENOMEM; p = strjoin("@", e); } else { if (path[path_len - 1] == '\0') /* We expect a terminating NUL and don't print it */ path_len--; p = cescape_length(path, path_len); } } if (!p) return -ENOMEM; break; case AF_VSOCK: if (include_port) { if (sa->vm.svm_cid == VMADDR_CID_ANY) r = asprintf(&p, "vsock::%u", sa->vm.svm_port); else r = asprintf(&p, "vsock:%u:%u", sa->vm.svm_cid, sa->vm.svm_port); } else r = asprintf(&p, "vsock:%u", sa->vm.svm_cid); if (r < 0) return -ENOMEM; break; default: return -EOPNOTSUPP; } *ret = p; return 0; } int getpeername_pretty(int fd, bool include_port, char **ret) { union sockaddr_union sa; socklen_t salen = sizeof(sa); int r; assert(fd >= 0); assert(ret); if (getpeername(fd, &sa.sa, &salen) < 0) return -errno; if (sa.sa.sa_family == AF_UNIX) { struct ucred ucred = UCRED_INVALID; /* UNIX connection sockets are anonymous, so let's use * PID/UID as pretty credentials instead */ r = getpeercred(fd, &ucred); if (r < 0) return r; if (asprintf(ret, "PID "PID_FMT"/UID "UID_FMT, ucred.pid, ucred.uid) < 0) return -ENOMEM; return 0; } /* For remote sockets we translate IPv6 addresses back to IPv4 * if applicable, since that's nicer. */ return sockaddr_pretty(&sa.sa, salen, true, include_port, ret); } int getsockname_pretty(int fd, char **ret) { union sockaddr_union sa; socklen_t salen = sizeof(sa); assert(fd >= 0); assert(ret); if (getsockname(fd, &sa.sa, &salen) < 0) return -errno; /* For local sockets we do not translate IPv6 addresses back * to IPv6 if applicable, since this is usually used for * listening sockets where the difference between IPv4 and * IPv6 matters. */ return sockaddr_pretty(&sa.sa, salen, false, true, ret); } int socknameinfo_pretty(const struct sockaddr *sa, socklen_t salen, char **ret) { char host[NI_MAXHOST]; int r; assert(sa); assert(salen >= sizeof(sa_family_t)); assert(ret); r = getnameinfo(sa, salen, host, sizeof(host), /* service= */ NULL, /* service_len= */ 0, IDN_FLAGS); if (r != 0) { if (r == EAI_MEMORY) return log_oom_debug(); if (r == EAI_SYSTEM) log_debug_errno(errno, "getnameinfo() failed, ignoring: %m"); else log_debug("getnameinfo() failed, ignoring: %s", gai_strerror(r)); return sockaddr_pretty(sa, salen, /* translate_ipv6= */ true, /* include_port= */ true, ret); } return strdup_to(ret, host); } static const char* const netlink_family_table[] = { [NETLINK_ROUTE] = "route", [NETLINK_FIREWALL] = "firewall", [NETLINK_INET_DIAG] = "inet-diag", [NETLINK_NFLOG] = "nflog", [NETLINK_XFRM] = "xfrm", [NETLINK_SELINUX] = "selinux", [NETLINK_ISCSI] = "iscsi", [NETLINK_AUDIT] = "audit", [NETLINK_FIB_LOOKUP] = "fib-lookup", [NETLINK_CONNECTOR] = "connector", [NETLINK_NETFILTER] = "netfilter", [NETLINK_IP6_FW] = "ip6-fw", [NETLINK_DNRTMSG] = "dnrtmsg", [NETLINK_KOBJECT_UEVENT] = "kobject-uevent", [NETLINK_GENERIC] = "generic", [NETLINK_SCSITRANSPORT] = "scsitransport", [NETLINK_ECRYPTFS] = "ecryptfs", [NETLINK_RDMA] = "rdma", }; DEFINE_STRING_TABLE_LOOKUP_WITH_FALLBACK(netlink_family, int, INT_MAX); bool sockaddr_equal(const union sockaddr_union *a, const union sockaddr_union *b) { assert(a); assert(b); if (a->sa.sa_family != b->sa.sa_family) return false; if (a->sa.sa_family == AF_INET) return a->in.sin_addr.s_addr == b->in.sin_addr.s_addr; if (a->sa.sa_family == AF_INET6) return memcmp(&a->in6.sin6_addr, &b->in6.sin6_addr, sizeof(a->in6.sin6_addr)) == 0; if (a->sa.sa_family == AF_VSOCK) return a->vm.svm_cid == b->vm.svm_cid; return false; } int fd_set_sndbuf(int fd, size_t n, bool increase) { int r, value; socklen_t l = sizeof(value); if (n > INT_MAX) return -ERANGE; r = getsockopt(fd, SOL_SOCKET, SO_SNDBUF, &value, &l); if (r >= 0 && l == sizeof(value) && increase ? (size_t) value >= n*2 : (size_t) value == n*2) return 0; /* First, try to set the buffer size with SO_SNDBUF. */ r = setsockopt_int(fd, SOL_SOCKET, SO_SNDBUF, n); if (r < 0) return r; /* SO_SNDBUF above may set to the kernel limit, instead of the requested size. * So, we need to check the actual buffer size here. */ l = sizeof(value); r = getsockopt(fd, SOL_SOCKET, SO_SNDBUF, &value, &l); if (r >= 0 && l == sizeof(value) && increase ? (size_t) value >= n*2 : (size_t) value == n*2) return 1; /* If we have the privileges we will ignore the kernel limit. */ r = setsockopt_int(fd, SOL_SOCKET, SO_SNDBUFFORCE, n); if (r < 0) return r; return 1; } int fd_set_rcvbuf(int fd, size_t n, bool increase) { int r, value; socklen_t l = sizeof(value); if (n > INT_MAX) return -ERANGE; r = getsockopt(fd, SOL_SOCKET, SO_RCVBUF, &value, &l); if (r >= 0 && l == sizeof(value) && increase ? (size_t) value >= n*2 : (size_t) value == n*2) return 0; /* First, try to set the buffer size with SO_RCVBUF. */ r = setsockopt_int(fd, SOL_SOCKET, SO_RCVBUF, n); if (r < 0) return r; /* SO_RCVBUF above may set to the kernel limit, instead of the requested size. * So, we need to check the actual buffer size here. */ l = sizeof(value); r = getsockopt(fd, SOL_SOCKET, SO_RCVBUF, &value, &l); if (r >= 0 && l == sizeof(value) && increase ? (size_t) value >= n*2 : (size_t) value == n*2) return 1; /* If we have the privileges we will ignore the kernel limit. */ r = setsockopt_int(fd, SOL_SOCKET, SO_RCVBUFFORCE, n); if (r < 0) return r; return 1; } static const char* const ip_tos_table[] = { [IPTOS_LOWDELAY] = "low-delay", [IPTOS_THROUGHPUT] = "throughput", [IPTOS_RELIABILITY] = "reliability", [IPTOS_LOWCOST] = "low-cost", }; DEFINE_STRING_TABLE_LOOKUP_WITH_FALLBACK(ip_tos, int, 0xff); bool ifname_valid_char(char a) { if ((unsigned char) a >= 127U) return false; if ((unsigned char) a <= 32U) return false; if (IN_SET(a, ':', /* colons are used by the legacy "alias" interface logic */ '/', /* slashes cannot work, since we need to use network interfaces in sysfs paths, and in paths slashes are separators */ '%')) /* %d is used in the kernel's weird foo%d format string naming feature which we really really don't want to ever run into by accident */ return false; return true; } bool ifname_valid_full(const char *p, IfnameValidFlags flags) { bool numeric = true; /* Checks whether a network interface name is valid. This is inspired by dev_valid_name() in the kernel sources * but slightly stricter, as we only allow non-control, non-space ASCII characters in the interface name. We * also don't permit names that only container numbers, to avoid confusion with numeric interface indexes. */ assert(!(flags & ~_IFNAME_VALID_ALL)); if (isempty(p)) return false; /* A valid ifindex? If so, it's valid iff IFNAME_VALID_NUMERIC is set */ if (parse_ifindex(p) >= 0) return flags & IFNAME_VALID_NUMERIC; if (flags & IFNAME_VALID_ALTERNATIVE) { if (strlen(p) >= ALTIFNAMSIZ) return false; } else { if (strlen(p) >= IFNAMSIZ) return false; } if (dot_or_dot_dot(p)) return false; /* Let's refuse "all" and "default" as interface name, to avoid collisions with the special sysctl * directories /proc/sys/net/{ipv4,ipv6}/conf/{all,default} */ if (!FLAGS_SET(flags, IFNAME_VALID_SPECIAL) && STR_IN_SET(p, "all", "default")) return false; for (const char *t = p; *t; t++) { if (!ifname_valid_char(*t)) return false; numeric = numeric && ascii_isdigit(*t); } /* It's fully numeric but didn't parse as valid ifindex above? if so, it must be too large or zero or * so, let's refuse that. */ if (numeric) return false; return true; } bool address_label_valid(const char *p) { POINTER_MAY_BE_NULL(p); if (isempty(p)) return false; if (strlen(p) >= IFNAMSIZ) return false; while (*p) { if ((uint8_t) *p >= 127U) return false; if ((uint8_t) *p <= 31U) return false; p++; } return true; } int getpeercred(int fd, struct ucred *ucred) { socklen_t n = sizeof(struct ucred); struct ucred u; assert(fd >= 0); assert(ucred); if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &u, &n) < 0) return -errno; if (n != sizeof(struct ucred)) return -EIO; /* Check if the data is actually useful and not suppressed due to namespacing issues */ if (!pid_is_valid(u.pid)) return -ENODATA; /* Note that we don't check UID/GID here, as namespace translation works differently there: instead of * receiving in "invalid" user/group we get the overflow UID/GID. */ *ucred = u; return 0; } int getpeersec(int fd, char **ret) { _cleanup_free_ char *s = NULL; socklen_t n = 64; assert(fd >= 0); assert(ret); for (;;) { s = new0(char, n+1); if (!s) return -ENOMEM; if (getsockopt(fd, SOL_SOCKET, SO_PEERSEC, s, &n) >= 0) { s[n] = 0; break; } if (errno != ERANGE) return -errno; s = mfree(s); } if (isempty(s)) return -EOPNOTSUPP; *ret = TAKE_PTR(s); return 0; } int getpeergroups(int fd, gid_t **ret) { socklen_t n = sizeof(gid_t) * 64U; _cleanup_free_ gid_t *d = NULL; assert(fd >= 0); assert(ret); long ngroups_max = sysconf(_SC_NGROUPS_MAX); if (ngroups_max > 0) n = MAX(n, sizeof(gid_t) * (socklen_t) ngroups_max); for (;;) { d = malloc(n); if (!d) return -ENOMEM; if (getsockopt(fd, SOL_SOCKET, SO_PEERGROUPS, d, &n) >= 0) break; if (errno != ERANGE) return -errno; d = mfree(d); } assert_se(n % sizeof(gid_t) == 0); n /= sizeof(gid_t); if (n > INT_MAX) return -E2BIG; *ret = TAKE_PTR(d); return (int) n; } int getpeerpidfd(int fd) { socklen_t n = sizeof(int); int pidfd = -EBADF; assert(fd >= 0); if (getsockopt(fd, SOL_SOCKET, SO_PEERPIDFD, &pidfd, &n) < 0) return -errno; if (n != sizeof(int)) return -EIO; return pidfd; } int getpeerpidref(int fd, PidRef *ret) { int r; assert(fd >= 0); assert(ret); int pidfd = getpeerpidfd(fd); if (pidfd < 0) { if (!ERRNO_IS_NEG_NOT_SUPPORTED(pidfd)) return pidfd; struct ucred ucred; r = getpeercred(fd, &ucred); if (r < 0) return r; return pidref_set_pid(ret, ucred.pid); } return pidref_set_pidfd_consume(ret, pidfd); } ssize_t send_one_fd_iov_sa( int transport_fd, int fd, const struct iovec *iov, size_t iovlen, const struct sockaddr *sa, socklen_t len, int flags) { CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(int))) control = {}; struct msghdr mh = { .msg_name = (struct sockaddr*) sa, .msg_namelen = len, .msg_iov = (struct iovec *)iov, .msg_iovlen = iovlen, }; ssize_t k; assert(transport_fd >= 0); /* * We need either an FD or data to send. * If there's nothing, return an error. */ if (fd < 0 && !iov) return -EINVAL; if (fd >= 0) { struct cmsghdr *cmsg; mh.msg_control = &control; mh.msg_controllen = sizeof(control); cmsg = CMSG_FIRSTHDR(&mh); cmsg->cmsg_level = SOL_SOCKET; cmsg->cmsg_type = SCM_RIGHTS; cmsg->cmsg_len = CMSG_LEN(sizeof(int)); memcpy(CMSG_DATA(cmsg), &fd, sizeof(int)); } k = sendmsg(transport_fd, &mh, MSG_NOSIGNAL | flags); if (k < 0) return (ssize_t) -errno; return k; } int send_one_fd_sa( int transport_fd, int fd, const struct sockaddr *sa, socklen_t len, int flags) { assert(fd >= 0); return (int) send_one_fd_iov_sa(transport_fd, fd, NULL, 0, sa, len, flags); } ssize_t receive_one_fd_iov( int transport_fd, struct iovec *iov, size_t iovlen, int flags, int *ret_fd) { CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(int))) control; struct msghdr mh = { .msg_control = &control, .msg_controllen = sizeof(control), .msg_iov = iov, .msg_iovlen = iovlen, }; struct cmsghdr *found; ssize_t k; assert(transport_fd >= 0); assert(ret_fd); /* * Receive a single FD via @transport_fd. We don't care for * the transport-type. We retrieve a single FD at most, so for * packet-based transports, the caller must ensure to send * only a single FD per packet. This is best used in * combination with send_one_fd(). */ k = recvmsg_safe(transport_fd, &mh, MSG_CMSG_CLOEXEC | flags); if (k < 0) return k; found = cmsg_find(&mh, SOL_SOCKET, SCM_RIGHTS, CMSG_LEN(sizeof(int))); if (!found) { cmsg_close_all(&mh); /* If didn't receive an FD or any data, return an error. */ if (k == 0) return -EIO; } if (found) *ret_fd = *CMSG_TYPED_DATA(found, int); else *ret_fd = -EBADF; return k; } int receive_one_fd(int transport_fd, int flags) { int fd; ssize_t k; k = receive_one_fd_iov(transport_fd, NULL, 0, flags, &fd); if (k == 0) return fd; /* k must be negative, since receive_one_fd_iov() only returns * a positive value if data was received through the iov. */ assert(k < 0); return (int) k; } ssize_t next_datagram_size_fd(int fd) { ssize_t l; int k; /* This is a bit like FIONREAD/SIOCINQ, however a bit more powerful. The difference being: recv(MSG_PEEK) will * actually cause the next datagram in the queue to be validated regarding checksums, which FIONREAD doesn't * do. This difference is actually of major importance as we need to be sure that the size returned here * actually matches what we will read with recvmsg() next, as otherwise we might end up allocating a buffer of * the wrong size. */ l = recv(fd, NULL, 0, MSG_PEEK|MSG_TRUNC); if (l < 0) { if (IN_SET(errno, EOPNOTSUPP, EFAULT)) goto fallback; return -errno; } if (l == 0) goto fallback; return l; fallback: k = 0; /* Some sockets (AF_PACKET) do not support null-sized recv() with MSG_TRUNC set, let's fall back to FIONREAD * for them. Checksums don't matter for raw sockets anyway, hence this should be fine. */ if (ioctl(fd, FIONREAD, &k) < 0) return -errno; return (ssize_t) k; } /* Put a limit on how many times will attempt to call accept4(). We loop * only on "transient" errors, but let's make sure we don't loop forever. */ #define MAX_FLUSH_ITERATIONS 1024 int flush_accept(int fd) { int r, b; socklen_t l = sizeof(b); /* Similar to flush_fd() but flushes all incoming connections by accepting and immediately closing * them. */ if (getsockopt(fd, SOL_SOCKET, SO_ACCEPTCONN, &b, &l) < 0) return -errno; assert(l == sizeof(b)); if (!b) /* Let's check if this socket accepts connections before calling accept(). accept4() can * return EOPNOTSUPP if the fd is not a listening socket, which we should treat as a fatal * error, or in case the incoming TCP connection triggered a network issue, which we want to * treat as a transient error. Thus, let's rule out the first reason for EOPNOTSUPP early, so * we can loop safely on transient errors below. */ return -ENOTTY; for (unsigned iteration = 0;; iteration++) { int cfd; r = fd_wait_for_event(fd, POLLIN, 0); if (r == -EINTR) continue; if (r <= 0) return r; if (iteration >= MAX_FLUSH_ITERATIONS) return log_debug_errno(SYNTHETIC_ERRNO(EBUSY), "Failed to flush connections within " STRINGIFY(MAX_FLUSH_ITERATIONS) " iterations."); cfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC); if (cfd < 0) { if (errno == EAGAIN) return 0; if (ERRNO_IS_ACCEPT_AGAIN(errno)) continue; return -errno; } safe_close(cfd); } } ssize_t flush_mqueue(int fd) { _cleanup_free_ char *buf = NULL; struct mq_attr attr; ssize_t count = 0; int r; assert(fd >= 0); /* Similar to flush_fd() but flushes all messages from a POSIX message queue. */ for (;;) { ssize_t l; r = fd_wait_for_event(fd, POLLIN, /* timeout= */ 0); if (r == -EINTR) continue; if (r < 0) return r; if (r == 0) return count; if (!buf) { /* Buffer must be at least as large as mq_msgsize. */ if (mq_getattr(fd, &attr) < 0) return -errno; buf = malloc(attr.mq_msgsize); if (!buf) return -ENOMEM; } l = mq_receive(fd, buf, attr.mq_msgsize, /* msg_prio= */ NULL); if (l < 0) { if (errno == EINTR) continue; if (errno == EAGAIN) return count; return -errno; } count += l; } } struct cmsghdr* cmsg_find(struct msghdr *mh, int level, int type, socklen_t length) { struct cmsghdr *cmsg; assert(mh); CMSG_FOREACH(cmsg, mh) if (cmsg->cmsg_level == level && cmsg->cmsg_type == type && (length == (socklen_t) -1 || length == cmsg->cmsg_len)) return cmsg; return NULL; } void* cmsg_find_and_copy_data(struct msghdr *mh, int level, int type, void *buf, size_t buf_len) { struct cmsghdr *cmsg; assert(mh); assert(buf); assert(buf_len > 0); /* This is similar to cmsg_find_data(), but copy the found data to buf. This should be typically used * when reading possibly unaligned data such as timestamp, as time_t is 64-bit and size_t is 32-bit on * RISCV32. See issue #27241. */ cmsg = cmsg_find(mh, level, type, CMSG_LEN(buf_len)); if (!cmsg) return NULL; return memcpy_safe(buf, CMSG_DATA(cmsg), buf_len); } size_t sockaddr_ll_len(const struct sockaddr_ll *sa) { /* Certain hardware address types (e.g Infiniband) do not fit into sll_addr * (8 bytes) and run over the structure. This function returns the correct size that * must be passed to kernel. */ assert(sa->sll_family == AF_PACKET); size_t mac_len = sizeof(sa->sll_addr); if (be16toh(sa->sll_hatype) == ARPHRD_ETHER) mac_len = MAX(mac_len, (size_t) ETH_ALEN); if (be16toh(sa->sll_hatype) == ARPHRD_INFINIBAND) mac_len = MAX(mac_len, (size_t) INFINIBAND_ALEN); return offsetof(struct sockaddr_ll, sll_addr) + mac_len; } size_t sockaddr_un_len(const struct sockaddr_un *sa) { /* Covers only file system and abstract AF_UNIX socket addresses, but not unnamed socket addresses. */ assert(sa->sun_family == AF_UNIX); return offsetof(struct sockaddr_un, sun_path) + (sa->sun_path[0] == 0 ? 1 + strnlen(sa->sun_path+1, sizeof(sa->sun_path)-1) : strnlen(sa->sun_path, sizeof(sa->sun_path))+1); } size_t sockaddr_len(const union sockaddr_union *sa) { switch (sa->sa.sa_family) { case AF_INET: return sizeof(struct sockaddr_in); case AF_INET6: return sizeof(struct sockaddr_in6); case AF_UNIX: return sockaddr_un_len(&sa->un); case AF_PACKET: return sockaddr_ll_len(&sa->ll); case AF_NETLINK: return sizeof(struct sockaddr_nl); case AF_VSOCK: return sizeof(struct sockaddr_vm); default: assert_not_reached(); } } int socket_ioctl_fd(void) { int fd; /* Create a socket to invoke the various network interface ioctl()s on. Traditionally only AF_INET was good for * that. Since kernel 4.6 AF_NETLINK works for this too. We first try to use AF_INET hence, but if that's not * available (for example, because it is made unavailable via SECCOMP or such), we'll fall back to the more * generic AF_NETLINK. */ fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC, 0); if (fd < 0) fd = socket(AF_NETLINK, SOCK_RAW|SOCK_CLOEXEC, NETLINK_GENERIC); if (fd < 0) return -errno; return fd; } int sockaddr_un_unlink(const struct sockaddr_un *sa) { const char *p, * nul; assert(sa); if (sa->sun_family != AF_UNIX) return -EPROTOTYPE; if (sa->sun_path[0] == 0) /* Nothing to do for abstract sockets */ return 0; /* The path in .sun_path is not necessarily NUL terminated. Let's fix that. */ nul = memchr(sa->sun_path, 0, sizeof(sa->sun_path)); if (nul) p = sa->sun_path; else p = memdupa_suffix0(sa->sun_path, sizeof(sa->sun_path)); if (unlink(p) < 0) return -errno; return 1; } int sockaddr_un_set_path(struct sockaddr_un *ret, const char *path) { size_t l; assert(ret); assert(path); /* Initialize ret->sun_path from the specified argument. This will interpret paths starting with '@' as * abstract namespace sockets, and those starting with '/' as regular filesystem sockets. It won't accept * anything else (i.e. no relative paths), to avoid ambiguities. Note that this function cannot be used to * reference paths in the abstract namespace that include NUL bytes in the name. */ l = strlen(path); if (l < 2) return -EINVAL; if (!IN_SET(path[0], '/', '@')) return -EINVAL; /* Don't allow paths larger than the space in sockaddr_un. Note that we are a tiny bit more restrictive than * the kernel is: we insist on NUL termination (both for abstract namespace and regular file system socket * addresses!), which the kernel doesn't. We do this to reduce chance of incompatibility with other apps that * do not expect non-NUL terminated file system path. */ if (l+1 > sizeof(ret->sun_path)) return path[0] == '@' ? -EINVAL : -ENAMETOOLONG; /* return a recognizable error if this is * too long to fit into a sockaddr_un, but * is a file system path, and thus might be * connectible via O_PATH indirection. */ *ret = (struct sockaddr_un) { .sun_family = AF_UNIX, }; if (path[0] == '@') { /* Abstract namespace socket */ memcpy(ret->sun_path + 1, path + 1, l); /* copy *with* trailing NUL byte */ return (int) (offsetof(struct sockaddr_un, sun_path) + l); /* 🔥 *don't* 🔥 include trailing NUL in size */ } else { assert(path[0] == '/'); /* File system socket */ memcpy(ret->sun_path, path, l + 1); /* copy *with* trailing NUL byte */ return (int) (offsetof(struct sockaddr_un, sun_path) + l + 1); /* include trailing NUL in size */ } } int getsockopt_int(int fd, int level, int optname, int *ret) { int v; socklen_t sl = sizeof(v); assert(fd >= 0); assert(ret); if (getsockopt(fd, level, optname, &v, &sl) < 0) return negative_errno(); if (sl != sizeof(v)) return -EIO; *ret = v; return 0; } int socket_bind_to_ifname(int fd, const char *ifname) { assert(fd >= 0); /* Call with NULL to drop binding */ return RET_NERRNO(setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen_ptr(ifname))); } int socket_bind_to_ifindex(int fd, int ifindex) { assert(fd >= 0); if (ifindex <= 0) /* Drop binding */ return RET_NERRNO(setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, NULL, 0)); return setsockopt_int(fd, SOL_SOCKET, SO_BINDTOIFINDEX, ifindex); } int socket_autobind(int fd, char **ret_name) { _cleanup_free_ char *name = NULL; uint64_t random; int r; /* Generate a random abstract socket name and bind fd to it. This is modeled after the kernel * "autobind" feature, but uses 64-bit random number internally. */ assert(fd >= 0); random = random_u64(); if (asprintf(&name, "@%" PRIu64, random) < 0) return -ENOMEM; union sockaddr_union sa; assert_cc(DECIMAL_STR_MAX(uint64_t) < sizeof(sa.un.sun_path)); r = sockaddr_un_set_path(&sa.un, name); if (r < 0) return r; if (bind(fd, &sa.sa, r) < 0) return -errno; if (ret_name) *ret_name = TAKE_PTR(name); return 0; } ssize_t recvmsg_safe(int sockfd, struct msghdr *msg, int flags) { ssize_t n; /* A wrapper around recvmsg() that checks for MSG_CTRUNC and MSG_TRUNC, and turns them into an error, * in a reasonably safe way, closing any received fds in the error path. * * Note that unlike our usual coding style this might modify *msg on failure. */ assert(sockfd >= 0); assert(msg); n = recvmsg(sockfd, msg, flags); if (n < 0) return -errno; if (FLAGS_SET(msg->msg_flags, MSG_CTRUNC) || (!FLAGS_SET(flags, MSG_PEEK) && FLAGS_SET(msg->msg_flags, MSG_TRUNC))) { cmsg_close_all(msg); return FLAGS_SET(msg->msg_flags, MSG_CTRUNC) ? -ECHRNG : -EXFULL; } return n; } int socket_get_family(int fd) { int af; socklen_t sl = sizeof(af); if (getsockopt(fd, SOL_SOCKET, SO_DOMAIN, &af, &sl) < 0) return -errno; if (sl != sizeof(af)) return -EINVAL; return af; } int socket_set_recvpktinfo(int fd, int af, bool b) { if (af == AF_UNSPEC) { af = socket_get_family(fd); if (af < 0) return af; } switch (af) { case AF_INET: return setsockopt_int(fd, IPPROTO_IP, IP_PKTINFO, b); case AF_INET6: return setsockopt_int(fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, b); case AF_NETLINK: return setsockopt_int(fd, SOL_NETLINK, NETLINK_PKTINFO, b); case AF_PACKET: return setsockopt_int(fd, SOL_PACKET, PACKET_AUXDATA, b); default: return -EAFNOSUPPORT; } } int socket_set_unicast_if(int fd, int af, int ifi) { be32_t ifindex_be = htobe32(ifi); if (af == AF_UNSPEC) { af = socket_get_family(fd); if (af < 0) return af; } switch (af) { case AF_INET: return RET_NERRNO(setsockopt(fd, IPPROTO_IP, IP_UNICAST_IF, &ifindex_be, sizeof(ifindex_be))); case AF_INET6: return RET_NERRNO(setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_IF, &ifindex_be, sizeof(ifindex_be))); default: return -EAFNOSUPPORT; } } int socket_set_option(int fd, int af, int opt_ipv4, int opt_ipv6, int val) { if (af == AF_UNSPEC) { af = socket_get_family(fd); if (af < 0) return af; } switch (af) { case AF_INET: return setsockopt_int(fd, IPPROTO_IP, opt_ipv4, val); case AF_INET6: return setsockopt_int(fd, IPPROTO_IPV6, opt_ipv6, val); default: return -EAFNOSUPPORT; } } int socket_get_mtu(int fd, int af, size_t *ret) { int mtu, r; assert(ret); if (af == AF_UNSPEC) { af = socket_get_family(fd); if (af < 0) return af; } switch (af) { case AF_INET: r = getsockopt_int(fd, IPPROTO_IP, IP_MTU, &mtu); break; case AF_INET6: r = getsockopt_int(fd, IPPROTO_IPV6, IPV6_MTU, &mtu); break; default: return -EAFNOSUPPORT; } if (r < 0) return r; if (mtu <= 0) return -EINVAL; *ret = (size_t) mtu; return 0; } static int connect_unix_path_simple(int fd, const char *path) { union sockaddr_union sa = { .un.sun_family = AF_UNIX, }; size_t l; assert(fd >= 0); assert(path); l = strlen(path); assert(l > 0); assert(l < sizeof(sa.un.sun_path)); memcpy(sa.un.sun_path, path, l + 1); return RET_NERRNO(connect(fd, &sa.sa, offsetof(struct sockaddr_un, sun_path) + l + 1)); } static int connect_unix_inode(int fd, int inode_fd) { assert(fd >= 0); assert(inode_fd >= 0); return connect_unix_path_simple(fd, FORMAT_PROC_FD_PATH(inode_fd)); } int connect_unix_path(int fd, int dir_fd, const char *path) { _cleanup_close_ int inode_fd = -EBADF; assert(fd >= 0); assert(wildcard_fd_is_valid(dir_fd)); /* Connects to the specified AF_UNIX socket in the file system. Works around the 108 byte size limit * in sockaddr_un, by going via O_PATH if needed. This hence works for any kind of path. */ if (!path) { if (dir_fd < 0) return -EISDIR; return connect_unix_inode(fd, dir_fd); /* If no path is specified, then dir_fd refers to the socket inode to connect to. */ } /* Refuse zero length path early, to make sure AF_UNIX stack won't mistake this for an abstract * namespace path, since first char is NUL */ if (isempty(path)) return -EINVAL; /* Shortcut for the simple case */ if (dir_fd == AT_FDCWD && strlen(path) < sizeof_field(struct sockaddr_un, sun_path)) return connect_unix_path_simple(fd, path); /* If dir_fd is specified, then we need to go the indirect O_PATH route, because connectat() does not * exist. If the path is too long, we also need to take the indirect route, since we can't fit this * into a sockaddr_un directly. */ if (dir_fd == XAT_FDROOT) { _cleanup_free_ char *j = strjoin("/", path); if (!j) return -ENOMEM; inode_fd = open(j, O_PATH|O_CLOEXEC); } else inode_fd = openat(dir_fd, path, O_PATH|O_CLOEXEC); if (inode_fd < 0) return -errno; return connect_unix_inode(fd, inode_fd); } int socket_address_parse_unix(SocketAddress *ret_address, const char *s) { struct sockaddr_un un; int r; assert(ret_address); assert(s); if (!IN_SET(*s, '/', '@')) return -EPROTO; r = sockaddr_un_set_path(&un, s); if (r < 0) return r; *ret_address = (SocketAddress) { .sockaddr.un = un, .size = r, }; return 0; } int socket_address_equal_unix(const char *a, const char *b) { SocketAddress socket_a, socket_b; int r; assert(a); assert(b); r = socket_address_parse_unix(&socket_a, a); if (r < 0) return r; r = socket_address_parse_unix(&socket_b, b); if (r < 0) return r; return sockaddr_equal(&socket_a.sockaddr, &socket_b.sockaddr); } int vsock_parse_port(const char *s, unsigned *ret) { int r; assert(ret); if (!s) return -EINVAL; unsigned u; r = safe_atou(s, &u); if (r < 0) return r; /* Port 0 is apparently valid and not special in AF_VSOCK (unlike on IP). But VMADDR_PORT_ANY * (UINT32_MAX) is. Hence refuse that. */ if (u == VMADDR_PORT_ANY) return -EINVAL; *ret = u; return 0; } int vsock_parse_cid(const char *s, unsigned *ret) { assert(ret); if (!s) return -EINVAL; /* Parsed an AF_VSOCK "CID". This is a 32bit entity, and the usual type is "unsigned". We recognize * the three special CIDs as strings, and otherwise parse the numeric CIDs. */ if (streq(s, "hypervisor")) *ret = VMADDR_CID_HYPERVISOR; else if (streq(s, "local")) *ret = VMADDR_CID_LOCAL; else if (streq(s, "host")) *ret = VMADDR_CID_HOST; else return safe_atou(s, ret); return 0; } int socket_address_parse_vsock(SocketAddress *ret_address, const char *s) { /* AF_VSOCK socket in vsock:cid:port notation */ _cleanup_free_ char *n = NULL; const char *e, *cid_start; unsigned port, cid; int type, r; assert(ret_address); assert(s); if ((cid_start = startswith(s, "vsock:"))) type = 0; else if ((cid_start = startswith(s, "vsock-dgram:"))) type = SOCK_DGRAM; else if ((cid_start = startswith(s, "vsock-seqpacket:"))) type = SOCK_SEQPACKET; else if ((cid_start = startswith(s, "vsock-stream:"))) type = SOCK_STREAM; else return -EPROTO; e = strchr(cid_start, ':'); if (!e) return -EINVAL; r = vsock_parse_port(e+1, &port); if (r < 0) return r; n = strndup(cid_start, e - cid_start); if (!n) return -ENOMEM; if (isempty(n)) cid = VMADDR_CID_ANY; else { r = vsock_parse_cid(n, &cid); if (r < 0) return r; } *ret_address = (SocketAddress) { .sockaddr.vm = { .svm_family = AF_VSOCK, .svm_cid = cid, .svm_port = port, }, .type = type, .size = sizeof(struct sockaddr_vm), }; return 0; } int netlink_socket_get_multicast_groups(int fd, size_t *ret_len, uint32_t **ret_groups) { _cleanup_free_ uint32_t *groups = NULL; socklen_t len = 0, old_len; assert(fd >= 0); if (getsockopt(fd, SOL_NETLINK, NETLINK_LIST_MEMBERSHIPS, NULL, &len) < 0) return -errno; if (len == 0) goto finalize; groups = new0(uint32_t, len); if (!groups) return -ENOMEM; old_len = len; if (getsockopt(fd, SOL_NETLINK, NETLINK_LIST_MEMBERSHIPS, groups, &len) < 0) return -errno; if (old_len != len) return -EIO; finalize: if (ret_len) *ret_len = len; if (ret_groups) *ret_groups = TAKE_PTR(groups); return 0; } int socket_get_cookie(int fd, uint64_t *ret) { assert(fd >= 0); uint64_t cookie = 0; socklen_t cookie_len = sizeof(cookie); if (getsockopt(fd, SOL_SOCKET, SO_COOKIE, &cookie, &cookie_len) < 0) return -errno; assert(cookie_len == sizeof(cookie)); if (ret) *ret = cookie; return 0; } void cmsg_close_all(struct msghdr *mh) { assert(mh); struct cmsghdr *cmsg; CMSG_FOREACH(cmsg, mh) { if (cmsg->cmsg_level != SOL_SOCKET) continue; if (cmsg->cmsg_type == SCM_RIGHTS) close_many(CMSG_TYPED_DATA(cmsg, int), (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int)); else if (cmsg->cmsg_type == SCM_PIDFD) { assert(cmsg->cmsg_len == CMSG_LEN(sizeof(int))); safe_close(*CMSG_TYPED_DATA(cmsg, int)); } } } int tos_to_priority(uint8_t tos) { /* Map the IP Precedence (top 3 bits of the TOS field) to Linux internal packet priorities * (TC_PRIO_*). This exactly mirrors the standard Linux kernel IP precedence-to-priority mapping * (rt_tos2priority) to ensure consistent behavior when explicitly setting SO_PRIORITY. */ switch (IPTOS_PREC(tos)) { case IPTOS_PREC_NETCONTROL: /* 0xc0 (CS7) - Network Control. Used for infrastructure control (e.g., STP, keepalives). */ case IPTOS_PREC_INTERNETCONTROL: /* 0xe0 (CS6) - Internetwork Control. Used for routing protocols (e.g., OSPF, BGP) and DHCP. */ return TC_PRIO_CONTROL; case IPTOS_PREC_CRITIC_ECP: /* 0xa0 (CS5) - Critical. Used for delay-sensitive traffic like Voice over IP (VoIP). */ case IPTOS_PREC_FLASHOVERRIDE: /* 0x80 (CS4) - Flash Override. Used for interactive video and multimedia. */ return TC_PRIO_INTERACTIVE; case IPTOS_PREC_FLASH: /* 0x60 (CS3) - Flash. Used for broadcast video and call signaling (e.g., SIP). */ case IPTOS_PREC_IMMEDIATE: /* 0x40 (CS2) - Immediate. Used for OAM (Operations, Administration, and Management) and transactional data. */ return TC_PRIO_INTERACTIVE_BULK; case IPTOS_PREC_PRIORITY: /* 0x20 (CS1) - Priority. Used for background traffic and bulk data transfers. */ return TC_PRIO_BULK; case IPTOS_PREC_ROUTINE: /* 0x00 (CS0) - Routine. Best effort traffic. */ default: return TC_PRIO_BESTEFFORT; } }