[398] | 1 | #define _GNU_SOURCE
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| 2 | #include <net/if.h>
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| 3 | #include <errno.h>
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| 4 | #include <unistd.h>
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| 5 | #include <stdlib.h>
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| 6 | #include <string.h>
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| 7 | #include <pthread.h>
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| 8 | #include "netlink.h"
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| 9 |
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| 10 | #define IFADDRS_HASH_SIZE 64
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| 11 |
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| 12 | struct ifnamemap {
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| 13 | unsigned int hash_next;
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| 14 | unsigned int index;
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| 15 | unsigned char namelen;
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| 16 | char name[IFNAMSIZ];
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| 17 | };
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| 18 |
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| 19 | struct ifnameindexctx {
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| 20 | unsigned int num, allocated, str_bytes;
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| 21 | struct ifnamemap *list;
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| 22 | unsigned int hash[IFADDRS_HASH_SIZE];
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| 23 | };
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| 24 |
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| 25 | static int netlink_msg_to_nameindex(void *pctx, struct nlmsghdr *h)
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| 26 | {
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| 27 | struct ifnameindexctx *ctx = pctx;
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| 28 | struct ifnamemap *map;
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| 29 | struct rtattr *rta;
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| 30 | unsigned int i;
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| 31 | int index, type, namelen, bucket;
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| 32 |
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| 33 | if (h->nlmsg_type == RTM_NEWLINK) {
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| 34 | struct ifinfomsg *ifi = NLMSG_DATA(h);
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| 35 | index = ifi->ifi_index;
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| 36 | type = IFLA_IFNAME;
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| 37 | rta = NLMSG_RTA(h, sizeof(*ifi));
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| 38 | } else {
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| 39 | struct ifaddrmsg *ifa = NLMSG_DATA(h);
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| 40 | index = ifa->ifa_index;
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| 41 | type = IFA_LABEL;
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| 42 | rta = NLMSG_RTA(h, sizeof(*ifa));
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| 43 | }
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| 44 | for (; NLMSG_RTAOK(rta, h); rta = RTA_NEXT(rta)) {
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| 45 | if (rta->rta_type != type) continue;
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| 46 |
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| 47 | namelen = RTA_DATALEN(rta) - 1;
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| 48 | if (namelen > IFNAMSIZ) return 0;
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| 49 |
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| 50 | /* suppress duplicates */
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| 51 | bucket = index % IFADDRS_HASH_SIZE;
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| 52 | i = ctx->hash[bucket];
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| 53 | while (i) {
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| 54 | map = &ctx->list[i-1];
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| 55 | if (map->index == index &&
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| 56 | map->namelen == namelen &&
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| 57 | memcmp(map->name, RTA_DATA(rta), namelen) == 0)
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| 58 | return 0;
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| 59 | i = map->hash_next;
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| 60 | }
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| 61 |
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| 62 | if (ctx->num >= ctx->allocated) {
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| 63 | size_t a = ctx->allocated ? ctx->allocated * 2 + 1 : 8;
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| 64 | if (a > SIZE_MAX/sizeof *map) return -1;
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| 65 | map = realloc(ctx->list, a * sizeof *map);
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| 66 | if (!map) return -1;
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| 67 | ctx->list = map;
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| 68 | ctx->allocated = a;
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| 69 | }
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| 70 | map = &ctx->list[ctx->num];
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| 71 | map->index = index;
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| 72 | map->namelen = namelen;
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| 73 | memcpy(map->name, RTA_DATA(rta), namelen);
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| 74 | ctx->str_bytes += namelen + 1;
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| 75 | ctx->num++;
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| 76 | map->hash_next = ctx->hash[bucket];
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| 77 | ctx->hash[bucket] = ctx->num;
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| 78 | return 0;
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| 79 | }
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| 80 | return 0;
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| 81 | }
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| 82 |
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| 83 | struct if_nameindex *if_nameindex()
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| 84 | {
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| 85 | struct ifnameindexctx _ctx, *ctx = &_ctx;
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| 86 | struct if_nameindex *ifs = 0, *d;
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| 87 | struct ifnamemap *s;
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| 88 | char *p;
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| 89 | int i;
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| 90 | int cs;
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| 91 |
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| 92 | pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
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| 93 | memset(ctx, 0, sizeof(*ctx));
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| 94 | if (__rtnetlink_enumerate(AF_UNSPEC, AF_INET, netlink_msg_to_nameindex, ctx) < 0) goto err;
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| 95 |
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| 96 | ifs = malloc(sizeof(struct if_nameindex[ctx->num+1]) + ctx->str_bytes);
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| 97 | if (!ifs) goto err;
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| 98 |
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| 99 | p = (char*)(ifs + ctx->num + 1);
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| 100 | for (i = ctx->num, d = ifs, s = ctx->list; i; i--, s++, d++) {
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| 101 | d->if_index = s->index;
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| 102 | d->if_name = p;
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| 103 | memcpy(p, s->name, s->namelen);
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| 104 | p += s->namelen;
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| 105 | *p++ = 0;
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| 106 | }
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| 107 | d->if_index = 0;
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| 108 | d->if_name = 0;
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| 109 | err:
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| 110 | pthread_setcancelstate(cs, 0);
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| 111 | free(ctx->list);
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| 112 | errno = ENOBUFS;
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| 113 | return ifs;
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| 114 | }
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