val = 255;
setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &val, sizeof(val));
+ // Receive multicast hops
+ val = 1;
+ setsockopt(sock, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &val, sizeof(val));
+
// Bind to one device
setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
bool ra_process(void)
{
bool found = false;
- uint8_t buf[1500];
+ uint8_t buf[1500], cmsg_buf[128];
struct nd_router_advert *adv = (struct nd_router_advert*)buf;
struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, IN6ADDR_ANY_INIT, 0, 0, 0};
const struct in6_addr any = IN6ADDR_ANY_INIT;
while (true) {
struct sockaddr_in6 from;
- socklen_t from_len = sizeof(from);
- ssize_t len = recvfrom(sock, buf, sizeof(buf), MSG_DONTWAIT, &from, &from_len);
+ struct iovec iov = {buf, sizeof(buf)};
+ struct msghdr msg = {&from, sizeof(from), &iov, 1,
+ cmsg_buf, sizeof(cmsg_buf), 0};
+
+ ssize_t len = recvmsg(sock, &msg, MSG_DONTWAIT);
if (len < 0)
break;
else if (len < (ssize_t)sizeof(*adv))
continue;
+ int hlim = 0;
+ for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
+ ch = CMSG_NXTHDR(&msg, ch))
+ if (ch->cmsg_level == IPPROTO_IPV6 &&
+ ch->cmsg_type == IPV6_HOPLIMIT)
+ memcpy(&hlim, CMSG_DATA(ch), sizeof(hlim));
+
+ if (hlim != 255)
+ continue;
+
// Stop sending solicits
if (rs_attempt > 0) {
alarm(0);