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Diffstat (limited to 'lib/isc/interfaceiter.c')
| -rw-r--r-- | lib/isc/interfaceiter.c | 518 |
1 files changed, 518 insertions, 0 deletions
diff --git a/lib/isc/interfaceiter.c b/lib/isc/interfaceiter.c new file mode 100644 index 0000000..566c5bd --- /dev/null +++ b/lib/isc/interfaceiter.c @@ -0,0 +1,518 @@ +/* + * 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 <sys/ioctl.h> +#include <sys/types.h> +#ifdef HAVE_SYS_SOCKIO_H +#include <sys/sockio.h> /* Required for ifiter_ioctl.c. */ +#endif /* ifdef HAVE_SYS_SOCKIO_H */ + +#include <errno.h> +#include <ifaddrs.h> +#include <inttypes.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> + +#include <isc/interfaceiter.h> +#include <isc/log.h> +#include <isc/magic.h> +#include <isc/mem.h> +#include <isc/net.h> +#include <isc/print.h> +#include <isc/result.h> +#include <isc/strerr.h> +#include <isc/string.h> +#include <isc/types.h> +#include <isc/util.h> + +/* Must follow <isc/net.h>. */ +#ifdef HAVE_NET_IF6_H +#include <net/if6.h> +#endif /* ifdef HAVE_NET_IF6_H */ +#include <net/if.h> + +/* 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)); +} |