115 lines
2.6 KiB
C
115 lines
2.6 KiB
C
#define _GNU_SOURCE
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#include <net/if.h>
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#include <errno.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <string.h>
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#include <pthread.h>
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#include "netlink.h"
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#define IFADDRS_HASH_SIZE 64
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struct ifnamemap {
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unsigned int hash_next;
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unsigned int index;
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unsigned char namelen;
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char name[IFNAMSIZ];
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};
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struct ifnameindexctx {
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unsigned int num, allocated, str_bytes;
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struct ifnamemap *list;
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unsigned int hash[IFADDRS_HASH_SIZE];
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};
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static int netlink_msg_to_nameindex(void *pctx, struct nlmsghdr *h)
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{
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struct ifnameindexctx *ctx = pctx;
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struct ifnamemap *map;
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struct rtattr *rta;
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unsigned int i;
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int index, type, namelen, bucket;
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if (h->nlmsg_type == RTM_NEWLINK) {
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struct ifinfomsg *ifi = NLMSG_DATA(h);
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index = ifi->ifi_index;
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type = IFLA_IFNAME;
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rta = NLMSG_RTA(h, sizeof(*ifi));
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} else {
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struct ifaddrmsg *ifa = NLMSG_DATA(h);
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index = ifa->ifa_index;
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type = IFA_LABEL;
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rta = NLMSG_RTA(h, sizeof(*ifa));
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}
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for (; NLMSG_RTAOK(rta, h); rta = RTA_NEXT(rta)) {
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if (rta->rta_type != type) continue;
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namelen = RTA_DATALEN(rta) - 1;
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if (namelen > IFNAMSIZ) return 0;
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/* suppress duplicates */
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bucket = index % IFADDRS_HASH_SIZE;
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i = ctx->hash[bucket];
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while (i) {
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map = &ctx->list[i-1];
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if (map->index == index &&
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map->namelen == namelen &&
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memcmp(map->name, RTA_DATA(rta), namelen) == 0)
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return 0;
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i = map->hash_next;
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}
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if (ctx->num >= ctx->allocated) {
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size_t a = ctx->allocated ? ctx->allocated * 2 + 1 : 8;
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if (a > SIZE_MAX/sizeof *map) return -1;
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map = realloc(ctx->list, a * sizeof *map);
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if (!map) return -1;
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ctx->list = map;
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ctx->allocated = a;
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}
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map = &ctx->list[ctx->num];
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map->index = index;
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map->namelen = namelen;
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memcpy(map->name, RTA_DATA(rta), namelen);
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ctx->str_bytes += namelen + 1;
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ctx->num++;
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map->hash_next = ctx->hash[bucket];
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ctx->hash[bucket] = ctx->num;
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return 0;
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}
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return 0;
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}
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struct if_nameindex *if_nameindex()
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{
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struct ifnameindexctx _ctx, *ctx = &_ctx;
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struct if_nameindex *ifs = 0, *d;
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struct ifnamemap *s;
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char *p;
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int i;
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int cs;
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pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
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memset(ctx, 0, sizeof(*ctx));
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if (__rtnetlink_enumerate(AF_UNSPEC, AF_INET, netlink_msg_to_nameindex, ctx) < 0) goto err;
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ifs = malloc(sizeof(struct if_nameindex[ctx->num+1]) + ctx->str_bytes);
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if (!ifs) goto err;
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p = (char*)(ifs + ctx->num + 1);
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for (i = ctx->num, d = ifs, s = ctx->list; i; i--, s++, d++) {
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d->if_index = s->index;
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d->if_name = p;
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memcpy(p, s->name, s->namelen);
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p += s->namelen;
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*p++ = 0;
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}
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d->if_index = 0;
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d->if_name = 0;
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err:
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pthread_setcancelstate(cs, 0);
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free(ctx->list);
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errno = ENOBUFS;
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return ifs;
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}
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