Function prepare_ifmap

tools/netstat/common.c:91–139

}

struct ifmap_entry *
prepare_ifmap(size_t *pifmap_size)
{
	int ifindex = 0, size;
	struct ifaddrs *ifap, *ifa;
	struct sockaddr_dl *sdl;

	struct ifmap_entry *ifmap = NULL;
	int ifmap_size = 0;

	/*
	 * Retrieve interface list at first
	 * since we need #ifindex -> if_xname match
	 */
	if (getifaddrs(&ifap) != 0)
		err(EX_OSERR, "getifaddrs");

	for (ifa = ifap; ifa; ifa = ifa->ifa_next) {

		if (ifa->ifa_addr->sa_family != AF_LINK)
			continue;

		sdl = (struct sockaddr_dl *)ifa->ifa_addr;
		ifindex = sdl->sdl_index;

		if (ifindex >= ifmap_size) {
			size = roundup(ifindex + 1, 32) *
			    sizeof(struct ifmap_entry);
			if ((ifmap = realloc(ifmap, size)) == NULL)
				errx(2, "realloc(%d) failed", size);
			memset(&ifmap[ifmap_size], 0,
			    size - ifmap_size *
			    sizeof(struct ifmap_entry));

			ifmap_size = roundup(ifindex + 1, 32);
		}

		if (*ifmap[ifindex].ifname != '\0')
			continue;

		strlcpy(ifmap[ifindex].ifname, ifa->ifa_name, IFNAMSIZ);
	}

	freeifaddrs(ifap);

	*pifmap_size = ifmap_size;

	return (ifmap);
}