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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 | #define _GNU_SOURCE #include <errno.h> #include <string.h> #include <stdlib.h> #include <unistd.h> #include <ifaddrs.h> #include <syscall.h> #include <net/if.h> #include <netinet/in.h> #include "netlink.h" #define IFADDRS_HASH_SIZE 64 /* getifaddrs() reports hardware addresses with PF_PACKET that implies * struct sockaddr_ll. But e.g. Infiniband socket address length is * longer than sockaddr_ll.ssl_addr[8] can hold. Use this hack struct * to extend ssl_addr - callers should be able to still use it. */ struct sockaddr_ll_hack { unsigned short sll_family, sll_protocol; int sll_ifindex; unsigned short sll_hatype; unsigned char sll_pkttype, sll_halen; unsigned char sll_addr[24]; }; union sockany { struct sockaddr sa; struct sockaddr_ll_hack ll; struct sockaddr_in v4; struct sockaddr_in6 v6; }; struct ifaddrs_storage { struct ifaddrs ifa; struct ifaddrs_storage *hash_next; union sockany addr, netmask, ifu; unsigned int index; char name[IFNAMSIZ+1]; }; struct ifaddrs_ctx { struct ifaddrs_storage *first; struct ifaddrs_storage *last; struct ifaddrs_storage *hash[IFADDRS_HASH_SIZE]; }; void freeifaddrs(struct ifaddrs *ifp) { struct ifaddrs *n; while (ifp) { n = ifp->ifa_next; free(ifp); ifp = n; } } static void copy_addr(struct sockaddr **r, int af, union sockany *sa, void *addr, size_t addrlen, int ifindex) { uint8_t *dst; int len; switch (af) { case AF_INET: dst = (uint8_t*) &sa->v4.sin_addr; len = 4; break; case AF_INET6: dst = (uint8_t*) &sa->v6.sin6_addr; len = 16; if (IN6_IS_ADDR_LINKLOCAL(addr) || IN6_IS_ADDR_MC_LINKLOCAL(addr)) sa->v6.sin6_scope_id = ifindex; break; default: return; } if (addrlen < len) return; sa->sa.sa_family = af; memcpy(dst, addr, len); *r = &sa->sa; } static void gen_netmask(struct sockaddr **r, int af, union sockany *sa, int prefixlen) { uint8_t addr[16] = {0}; int i; if (prefixlen > 8*sizeof(addr)) prefixlen = 8*sizeof(addr); i = prefixlen / 8; memset(addr, 0xff, i); if (i < sizeof(addr)) addr[i++] = 0xff << (8 - (prefixlen % 8)); copy_addr(r, af, sa, addr, sizeof(addr), 0); } static void copy_lladdr(struct sockaddr **r, union sockany *sa, void *addr, size_t addrlen, int ifindex, unsigned short hatype) { if (addrlen > sizeof(sa->ll.sll_addr)) return; sa->ll.sll_family = AF_PACKET; sa->ll.sll_ifindex = ifindex; sa->ll.sll_hatype = hatype; sa->ll.sll_halen = addrlen; memcpy(sa->ll.sll_addr, addr, addrlen); *r = &sa->sa; } static int netlink_msg_to_ifaddr(void *pctx, struct nlmsghdr *h) { struct ifaddrs_ctx *ctx = pctx; struct ifaddrs_storage *ifs, *ifs0; struct ifinfomsg *ifi = NLMSG_DATA(h); struct ifaddrmsg *ifa = NLMSG_DATA(h); struct rtattr *rta; int stats_len = 0; if (h->nlmsg_type == RTM_NEWLINK) { for (rta = NLMSG_RTA(h, sizeof(*ifi)); NLMSG_RTAOK(rta, h); rta = RTA_NEXT(rta)) { if (rta->rta_type != IFLA_STATS) continue; stats_len = RTA_DATALEN(rta); break; } } else { for (ifs0 = ctx->hash[ifa->ifa_index % IFADDRS_HASH_SIZE]; ifs0; ifs0 = ifs0->hash_next) if (ifs0->index == ifa->ifa_index) break; if (!ifs0) return 0; } ifs = calloc(1, sizeof(struct ifaddrs_storage) + stats_len); if (ifs == 0) return -1; if (h->nlmsg_type == RTM_NEWLINK) { ifs->index = ifi->ifi_index; ifs->ifa.ifa_flags = ifi->ifi_flags; for (rta = NLMSG_RTA(h, sizeof(*ifi)); NLMSG_RTAOK(rta, h); rta = RTA_NEXT(rta)) { switch (rta->rta_type) { case IFLA_IFNAME: if (RTA_DATALEN(rta) < sizeof(ifs->name)) { memcpy(ifs->name, RTA_DATA(rta), RTA_DATALEN(rta)); ifs->ifa.ifa_name = ifs->name; } break; case IFLA_ADDRESS: copy_lladdr(&ifs->ifa.ifa_addr, &ifs->addr, RTA_DATA(rta), RTA_DATALEN(rta), ifi->ifi_index, ifi->ifi_type); break; case IFLA_BROADCAST: copy_lladdr(&ifs->ifa.ifa_broadaddr, &ifs->ifu, RTA_DATA(rta), RTA_DATALEN(rta), ifi->ifi_index, ifi->ifi_type); break; case IFLA_STATS: ifs->ifa.ifa_data = (void*)(ifs+1); memcpy(ifs->ifa.ifa_data, RTA_DATA(rta), RTA_DATALEN(rta)); break; } } if (ifs->ifa.ifa_name) { unsigned int bucket = ifs->index % IFADDRS_HASH_SIZE; ifs->hash_next = ctx->hash[bucket]; ctx->hash[bucket] = ifs; } } else { ifs->ifa.ifa_name = ifs0->ifa.ifa_name; ifs->ifa.ifa_flags = ifs0->ifa.ifa_flags; for (rta = NLMSG_RTA(h, sizeof(*ifa)); NLMSG_RTAOK(rta, h); rta = RTA_NEXT(rta)) { switch (rta->rta_type) { case IFA_ADDRESS: /* If ifa_addr is already set we, received an IFA_LOCAL before * so treat this as destination address */ if (ifs->ifa.ifa_addr) copy_addr(&ifs->ifa.ifa_dstaddr, ifa->ifa_family, &ifs->ifu, RTA_DATA(rta), RTA_DATALEN(rta), ifa->ifa_index); else copy_addr(&ifs->ifa.ifa_addr, ifa->ifa_family, &ifs->addr, RTA_DATA(rta), RTA_DATALEN(rta), ifa->ifa_index); break; case IFA_BROADCAST: copy_addr(&ifs->ifa.ifa_broadaddr, ifa->ifa_family, &ifs->ifu, RTA_DATA(rta), RTA_DATALEN(rta), ifa->ifa_index); break; case IFA_LOCAL: /* If ifa_addr is set and we get IFA_LOCAL, assume we have * a point-to-point network. Move address to correct field. */ if (ifs->ifa.ifa_addr) { ifs->ifu = ifs->addr; ifs->ifa.ifa_dstaddr = &ifs->ifu.sa; memset(&ifs->addr, 0, sizeof(ifs->addr)); } copy_addr(&ifs->ifa.ifa_addr, ifa->ifa_family, &ifs->addr, RTA_DATA(rta), RTA_DATALEN(rta), ifa->ifa_index); break; case IFA_LABEL: if (RTA_DATALEN(rta) < sizeof(ifs->name)) { memcpy(ifs->name, RTA_DATA(rta), RTA_DATALEN(rta)); ifs->ifa.ifa_name = ifs->name; } break; } } if (ifs->ifa.ifa_addr) gen_netmask(&ifs->ifa.ifa_netmask, ifa->ifa_family, &ifs->netmask, ifa->ifa_prefixlen); } if (ifs->ifa.ifa_name) { if (!ctx->first) ctx->first = ifs; if (ctx->last) ctx->last->ifa.ifa_next = &ifs->ifa; ctx->last = ifs; } else { free(ifs); } return 0; } int getifaddrs(struct ifaddrs **ifap) { struct ifaddrs_ctx _ctx, *ctx = &_ctx; int r; memset(ctx, 0, sizeof *ctx); r = __rtnetlink_enumerate(AF_UNSPEC, AF_UNSPEC, netlink_msg_to_ifaddr, ctx); if (r == 0) *ifap = &ctx->first->ifa; else freeifaddrs(&ctx->first->ifa); return r; } |