MT#55283 enable PKTINFO for UDP listeners

These may be bound to ANY so we want to know which local address each
packet was sent to.

Change-Id: I91e40e0b8000e44859255286e13b8f4c5d63b59f

daemon/udp_listener.c

@@ -39,7 +39,8 @@ static void udp_listener_incoming(int fd, void *p, uintptr_t x) {
 			udp_buf->listener = cb->ul;
 		}
 
-		len = socket_recvfrom(udp_buf->listener, udp_buf->str.s, MAX_UDP_LENGTH, &udp_buf->sin);
+		len = socket_recvfrom_to(udp_buf->listener, udp_buf->str.s, MAX_UDP_LENGTH, &udp_buf->sin,
+				&udp_buf->local_addr);
 		if (len < 0) {
 			if (errno == EINTR)
 				continue;
@@ -87,6 +88,8 @@ int udp_listener_init(socket_t *sock, const endpoint_t *ep,
 	if (open_socket(sock, SOCK_DGRAM, ep->port, &ep->address))
 		goto fail;
 
+	socket_pktinfo(sock);
+
 	ZERO(i);
 	i.fd = sock->fd;
 	i.closed = udp_listener_closed;

include/udp_listener.h

@@ -15,6 +15,7 @@ struct udp_buffer {
 	char buf[MAX_UDP_LENGTH + RTP_BUFFER_TAIL_ROOM + RTP_BUFFER_HEAD_ROOM + 1];
 	str str;
 	endpoint_t sin;
+	sockaddr_t local_addr;
 	char addr[64];
 	socket_t *listener;
 };