-static int
-dns_send_packet(int fd, struct iovec *iov, int iov_len)
-{
- static size_t cmsg_data[( CMSG_SPACE(sizeof(struct in_pktinfo)) / sizeof(size_t)) + 1];
- static struct sockaddr_in a = {
- .sin_family = AF_INET,
- .sin_port = htons(MCAST_PORT),
- };
- static struct msghdr m = {
- .msg_name = (struct sockaddr *) &a,
- .msg_namelen = sizeof(a),
- .msg_control = cmsg_data,
- .msg_controllen = CMSG_LEN(sizeof(struct in_pktinfo)),
- };
- struct in_pktinfo *pkti;
- struct cmsghdr *cmsg;
-
- m.msg_iov = iov;
- m.msg_iovlen = iov_len;
-
- memset(cmsg_data, 0, sizeof(cmsg_data));
- cmsg = CMSG_FIRSTHDR(&m);
- cmsg->cmsg_len = m.msg_controllen;
- cmsg->cmsg_level = IPPROTO_IP;
- cmsg->cmsg_type = IP_PKTINFO;
-
- pkti = (struct in_pktinfo*) CMSG_DATA(cmsg);
- pkti->ipi_ifindex = iface_index;
-
- a.sin_addr.s_addr = inet_addr(MCAST_ADDR);
-
- return sendmsg(fd, &m, 0);
-}
-