/* $NetBSD: interfaceiter.c,v 1.2.2.2 2024/02/25 15:47:16 martin Exp $ */ /* * Copyright (C) Internet Systems Consortium, Inc. ("ISC") * * SPDX-License-Identifier: MPL-2.0 * * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, you can obtain one at https://mozilla.org/MPL/2.0/. * * See the COPYRIGHT file distributed with this work for additional * information regarding copyright ownership. */ /*! \file */ #include #include #ifdef HAVE_SYS_SOCKIO_H #include /* Required for ifiter_ioctl.c. */ #endif /* ifdef HAVE_SYS_SOCKIO_H */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* Must follow . */ #ifdef HAVE_NET_IF6_H #include #endif /* ifdef HAVE_NET_IF6_H */ #include /* Common utility functions */ /*% * Extract the network address part from a "struct sockaddr". * \brief * The address family is given explicitly * instead of using src->sa_family, because the latter does not work * for copying a network mask obtained by SIOCGIFNETMASK (it does * not have a valid address family). */ static void get_addr(unsigned int family, isc_netaddr_t *dst, struct sockaddr *src, char *ifname) { struct sockaddr_in6 *sa6; #if !defined(HAVE_IF_NAMETOINDEX) UNUSED(ifname); #endif /* if !defined(HAVE_IF_NAMETOINDEX) */ /* clear any remaining value for safety */ memset(dst, 0, sizeof(*dst)); dst->family = family; switch (family) { case AF_INET: memmove(&dst->type.in, &((struct sockaddr_in *)src)->sin_addr, sizeof(struct in_addr)); break; case AF_INET6: sa6 = (struct sockaddr_in6 *)src; memmove(&dst->type.in6, &sa6->sin6_addr, sizeof(struct in6_addr)); if (sa6->sin6_scope_id != 0) { isc_netaddr_setzone(dst, sa6->sin6_scope_id); } else { /* * BSD variants embed scope zone IDs in the 128bit * address as a kernel internal form. Unfortunately, * the embedded IDs are not hidden from applications * when getting access to them by sysctl or ioctl. * We convert the internal format to the pure address * part and the zone ID part. * Since multicast addresses should not appear here * and they cannot be distinguished from netmasks, * we only consider unicast link-local addresses. */ if (IN6_IS_ADDR_LINKLOCAL(&sa6->sin6_addr)) { uint16_t zone16; memmove(&zone16, &sa6->sin6_addr.s6_addr[2], sizeof(zone16)); zone16 = ntohs(zone16); if (zone16 != 0) { /* the zone ID is embedded */ isc_netaddr_setzone(dst, (uint32_t)zone16); dst->type.in6.s6_addr[2] = 0; dst->type.in6.s6_addr[3] = 0; #ifdef HAVE_IF_NAMETOINDEX } else if (ifname != NULL) { unsigned int zone; /* * sin6_scope_id is still not provided, * but the corresponding interface name * is know. Use the interface ID as * the link ID. */ zone = if_nametoindex(ifname); if (zone != 0) { isc_netaddr_setzone( dst, (uint32_t)zone); } #endif /* ifdef HAVE_IF_NAMETOINDEX */ } } } break; default: UNREACHABLE(); } } /* * Include system-dependent code. */ #ifdef __linux #define ISC_IF_INET6_SZ \ sizeof("00000000000000000000000000000001 01 80 10 80 " \ "XXXXXXloXXXXXXXX\n") static isc_result_t linux_if_inet6_next(isc_interfaceiter_t *); static isc_result_t linux_if_inet6_current(isc_interfaceiter_t *); static void linux_if_inet6_first(isc_interfaceiter_t *iter); #endif /* ifdef __linux */ /*% Iterator Magic */ #define IFITER_MAGIC ISC_MAGIC('I', 'F', 'I', 'G') /*% Valid Iterator */ #define VALID_IFITER(t) ISC_MAGIC_VALID(t, IFITER_MAGIC) #ifdef __linux static bool seenv6 = false; #endif /* ifdef __linux */ /*% Iterator structure */ struct isc_interfaceiter { unsigned int magic; /*%< Magic number. */ isc_mem_t *mctx; void *buf; /*%< (unused) */ unsigned int bufsize; /*%< (always 0) */ struct ifaddrs *ifaddrs; /*%< List of ifaddrs */ struct ifaddrs *pos; /*%< Ptr to current ifaddr */ isc_interface_t current; /*%< Current interface data. */ isc_result_t result; /*%< Last result code. */ #ifdef __linux FILE *proc; char entry[ISC_IF_INET6_SZ]; isc_result_t valid; #endif /* ifdef __linux */ }; isc_result_t isc_interfaceiter_create(isc_mem_t *mctx, isc_interfaceiter_t **iterp) { isc_interfaceiter_t *iter; isc_result_t result; char strbuf[ISC_STRERRORSIZE]; REQUIRE(mctx != NULL); REQUIRE(iterp != NULL); REQUIRE(*iterp == NULL); iter = isc_mem_get(mctx, sizeof(*iter)); iter->mctx = mctx; iter->buf = NULL; iter->bufsize = 0; iter->ifaddrs = NULL; #ifdef __linux /* * Only open "/proc/net/if_inet6" if we have never seen a IPv6 * address returned by getifaddrs(). */ if (!seenv6) { iter->proc = fopen("/proc/net/if_inet6", "r"); } else { iter->proc = NULL; } iter->valid = ISC_R_FAILURE; #endif /* ifdef __linux */ if (getifaddrs(&iter->ifaddrs) < 0) { strerror_r(errno, strbuf, sizeof(strbuf)); UNEXPECTED_ERROR("getting interface addresses: getifaddrs: %s", strbuf); result = ISC_R_UNEXPECTED; goto failure; } /* * A newly created iterator has an undefined position * until isc_interfaceiter_first() is called. */ iter->pos = NULL; iter->result = ISC_R_FAILURE; iter->magic = IFITER_MAGIC; *iterp = iter; return (ISC_R_SUCCESS); failure: #ifdef __linux if (iter->proc != NULL) { fclose(iter->proc); } #endif /* ifdef __linux */ if (iter->ifaddrs != NULL) { /* just in case */ freeifaddrs(iter->ifaddrs); } isc_mem_put(mctx, iter, sizeof(*iter)); return (result); } /* * Get information about the current interface to iter->current. * If successful, return ISC_R_SUCCESS. * If the interface has an unsupported address family, * return ISC_R_IGNORE. */ static isc_result_t internal_current(isc_interfaceiter_t *iter) { struct ifaddrs *ifa; int family; unsigned int namelen; REQUIRE(VALID_IFITER(iter)); ifa = iter->pos; #ifdef __linux if (iter->pos == NULL) { return (linux_if_inet6_current(iter)); } #endif /* ifdef __linux */ INSIST(ifa != NULL); INSIST(ifa->ifa_name != NULL); if (ifa->ifa_addr == NULL) { return (ISC_R_IGNORE); } family = ifa->ifa_addr->sa_family; if (family != AF_INET && family != AF_INET6) { return (ISC_R_IGNORE); } #ifdef __linux if (family == AF_INET6) { seenv6 = true; } #endif /* ifdef __linux */ memset(&iter->current, 0, sizeof(iter->current)); namelen = strlen(ifa->ifa_name); if (namelen > sizeof(iter->current.name) - 1) { namelen = sizeof(iter->current.name) - 1; } memset(iter->current.name, 0, sizeof(iter->current.name)); memmove(iter->current.name, ifa->ifa_name, namelen); iter->current.flags = 0; if ((ifa->ifa_flags & IFF_UP) != 0) { iter->current.flags |= INTERFACE_F_UP; } if ((ifa->ifa_flags & IFF_POINTOPOINT) != 0) { iter->current.flags |= INTERFACE_F_POINTTOPOINT; } if ((ifa->ifa_flags & IFF_LOOPBACK) != 0) { iter->current.flags |= INTERFACE_F_LOOPBACK; } iter->current.af = family; get_addr(family, &iter->current.address, ifa->ifa_addr, ifa->ifa_name); if (ifa->ifa_netmask != NULL) { get_addr(family, &iter->current.netmask, ifa->ifa_netmask, ifa->ifa_name); } if (ifa->ifa_dstaddr != NULL && (iter->current.flags & INTERFACE_F_POINTTOPOINT) != 0) { get_addr(family, &iter->current.dstaddress, ifa->ifa_dstaddr, ifa->ifa_name); } return (ISC_R_SUCCESS); } /* * Step the iterator to the next interface. Unlike * isc_interfaceiter_next(), this may leave the iterator * positioned on an interface that will ultimately * be ignored. Return ISC_R_NOMORE if there are no more * interfaces, otherwise ISC_R_SUCCESS. */ static isc_result_t internal_next(isc_interfaceiter_t *iter) { if (iter->pos != NULL) { iter->pos = iter->pos->ifa_next; } if (iter->pos == NULL) { #ifdef __linux if (!seenv6) { return (linux_if_inet6_next(iter)); } #endif /* ifdef __linux */ return (ISC_R_NOMORE); } return (ISC_R_SUCCESS); } static void internal_destroy(isc_interfaceiter_t *iter) { #ifdef __linux if (iter->proc != NULL) { fclose(iter->proc); } iter->proc = NULL; #endif /* ifdef __linux */ if (iter->ifaddrs) { freeifaddrs(iter->ifaddrs); } iter->ifaddrs = NULL; } static void internal_first(isc_interfaceiter_t *iter) { #ifdef __linux linux_if_inet6_first(iter); #endif /* ifdef __linux */ iter->pos = iter->ifaddrs; } #ifdef __linux static void linux_if_inet6_first(isc_interfaceiter_t *iter) { if (iter->proc != NULL) { rewind(iter->proc); (void)linux_if_inet6_next(iter); } else { iter->valid = ISC_R_NOMORE; } } static isc_result_t linux_if_inet6_next(isc_interfaceiter_t *iter) { if (iter->proc != NULL && fgets(iter->entry, sizeof(iter->entry), iter->proc) != NULL) { iter->valid = ISC_R_SUCCESS; } else { iter->valid = ISC_R_NOMORE; } return (iter->valid); } static isc_result_t linux_if_inet6_current(isc_interfaceiter_t *iter) { char address[33]; char name[IF_NAMESIZE + 1]; struct in6_addr addr6; unsigned int ifindex, prefix, flag3, flag4; int res; unsigned int i; if (iter->valid != ISC_R_SUCCESS) { return (iter->valid); } if (iter->proc == NULL) { isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL, ISC_LOGMODULE_INTERFACE, ISC_LOG_ERROR, "/proc/net/if_inet6:iter->proc == NULL"); return (ISC_R_FAILURE); } res = sscanf(iter->entry, "%32[a-f0-9] %x %x %x %x %16s\n", address, &ifindex, &prefix, &flag3, &flag4, name); if (res != 6) { isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL, ISC_LOGMODULE_INTERFACE, ISC_LOG_ERROR, "/proc/net/if_inet6:sscanf() -> %d (expected 6)", res); return (ISC_R_FAILURE); } if (strlen(address) != 32) { isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL, ISC_LOGMODULE_INTERFACE, ISC_LOG_ERROR, "/proc/net/if_inet6:strlen(%s) != 32", address); return (ISC_R_FAILURE); } for (i = 0; i < 16; i++) { unsigned char byte; static const char hex[] = "0123456789abcdef"; byte = ((strchr(hex, address[i * 2]) - hex) << 4) | (strchr(hex, address[i * 2 + 1]) - hex); addr6.s6_addr[i] = byte; } iter->current.af = AF_INET6; iter->current.flags = INTERFACE_F_UP; isc_netaddr_fromin6(&iter->current.address, &addr6); if (isc_netaddr_islinklocal(&iter->current.address)) { isc_netaddr_setzone(&iter->current.address, (uint32_t)ifindex); } for (i = 0; i < 16; i++) { if (prefix > 8) { addr6.s6_addr[i] = 0xff; prefix -= 8; } else { addr6.s6_addr[i] = (0xff << (8 - prefix)) & 0xff; prefix = 0; } } isc_netaddr_fromin6(&iter->current.netmask, &addr6); strlcpy(iter->current.name, name, sizeof(iter->current.name)); return (ISC_R_SUCCESS); } #endif /* ifdef __linux */ /* * The remaining code is common to the sysctl and ioctl case. */ isc_result_t isc_interfaceiter_current(isc_interfaceiter_t *iter, isc_interface_t *ifdata) { REQUIRE(iter->result == ISC_R_SUCCESS); memmove(ifdata, &iter->current, sizeof(*ifdata)); return (ISC_R_SUCCESS); } isc_result_t isc_interfaceiter_first(isc_interfaceiter_t *iter) { isc_result_t result; REQUIRE(VALID_IFITER(iter)); internal_first(iter); for (;;) { result = internal_current(iter); if (result != ISC_R_IGNORE) { break; } result = internal_next(iter); if (result != ISC_R_SUCCESS) { break; } } iter->result = result; return (result); } isc_result_t isc_interfaceiter_next(isc_interfaceiter_t *iter) { isc_result_t result; REQUIRE(VALID_IFITER(iter)); REQUIRE(iter->result == ISC_R_SUCCESS); for (;;) { result = internal_next(iter); if (result != ISC_R_SUCCESS) { break; } result = internal_current(iter); if (result != ISC_R_IGNORE) { break; } } iter->result = result; return (result); } void isc_interfaceiter_destroy(isc_interfaceiter_t **iterp) { isc_interfaceiter_t *iter; REQUIRE(iterp != NULL); iter = *iterp; *iterp = NULL; REQUIRE(VALID_IFITER(iter)); internal_destroy(iter); if (iter->buf != NULL) { isc_mem_put(iter->mctx, iter->buf, iter->bufsize); } iter->magic = 0; isc_mem_put(iter->mctx, iter, sizeof(*iter)); }