added proper accessor functions for pcb->multicast_ip (previously used by get/setsockopt only)

CHANGELOG

@@ -202,6 +202,10 @@ HISTORY
 
   ++ Bugfixes:
 
+  2015-02-22: Simon Goldschmidt
+  * udp.h, sockets.c: added proper accessor functions for pcb->multicast_ip
+    (previously used by get/setsockopt only)
+
   2015-02-18: Simon Goldschmidt
   * sockets.c: Fixed select not reporting received FIN as 'readable' in certain
     rare cases (bug #43779: select(), close(), and TCP retransmission error)
@@ -209,7 +213,7 @@ HISTORY
   2015-02-17: Simon Goldschmidt
   * err.h, sockets.c, api_msg.c: fixed bug #38853 "connect() use a wrong errno":
     return ERR_ALREADY/EALRADY during connect, ERR_ISCONN/EISCONN when already
-	connected
+    connected
 
   2015-02-17: Simon Goldschmidt
   * tcp_impl.h, tcp_out.c, tcp.c, api_msg.c: fixed bug #37614 "Errors from

src/api/sockets.c

@@ -1784,7 +1784,7 @@ lwip_getsockopt_impl(int s, int level, int optname, void *optval, socklen_t *opt
       if (NETCONNTYPE_GROUP(netconn_type(sock->conn)) != NETCONN_UDP) {
         return ENOPROTOOPT;
       }
-      inet_addr_from_ipaddr((struct in_addr*)optval, &sock->conn->pcb.udp->multicast_ip);
+      inet_addr_from_ipaddr((struct in_addr*)optval, udp_get_multicast_netif_addr(sock->conn->pcb.udp));
       LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_IP, IP_MULTICAST_IF) = 0x%"X32_F"\n",
                   s, *(u32_t *)optval));
       break;
@@ -2135,8 +2135,12 @@ lwip_setsockopt_impl(int s, int level, int optname, const void *optval, socklen_
       sock->conn->pcb.udp->ttl = (u8_t)(*(u8_t*)optval);
       break;
     case IP_MULTICAST_IF:
-      LWIP_SOCKOPT_CHECK_OPTLEN_CONN_PCB_TYPE(sock, optlen, struct in_addr, NETCONN_UDP);
-      inet_addr_to_ipaddr(&sock->conn->pcb.udp->multicast_ip, (struct in_addr*)optval);
+      {
+        ip_addr_t if_addr;
+        LWIP_SOCKOPT_CHECK_OPTLEN_CONN_PCB_TYPE(sock, optlen, struct in_addr, NETCONN_UDP);
+        inet_addr_to_ipaddr(&if_addr, (struct in_addr*)optval);
+        udp_set_multicast_netif_addr(sock->conn->pcb.udp, &if_addr);
+      }
       break;
     case IP_MULTICAST_LOOP:
       LWIP_SOCKOPT_CHECK_OPTLEN_CONN_PCB_TYPE(sock, optlen, u8_t, NETCONN_UDP);

src/include/lwip/udp.h

@@ -206,6 +206,11 @@ struct udp_pcb * udp_new_ip6(void);
 #endif /*LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_UDP */
 #endif /* LWIP_IPV6 */
 
+#if LWIP_IGMP
+#define udp_set_multicast_netif_addr(pcb, ip4addr) ((pcb)->multicast_ip = *(ip4addr))
+#define udp_get_multicast_netif_addr(pcb)          (&(pcb)->multicast_ip)
+#endif /* LWIP_IGMP */
+
 #if UDP_DEBUG
 void udp_debug_print(struct udp_hdr *udphdr);
 #else