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