Cleaned up using struct netif.ip_addr by creating API functions for it

src/core/ipv4/icmp.c

@@ -120,7 +120,7 @@ icmp_input(struct pbuf *p, struct netif *inp)
     if (ip_addr_isbroadcast(ip_current_dest_addr(), ip_current_netif())) {
 #if LWIP_BROADCAST_PING
       /* For broadcast, use address of receiving interface as source address */
-      src = &inp->ip_addr;
+      src = netif_ip4_addr(inp);
 #else /* LWIP_BROADCAST_PING */
       LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to broadcast pings\n"));
       goto icmperr;

src/core/udp.c

@@ -683,7 +683,7 @@ udp_sendto_if_chksum(struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *dst_i
 #if LWIP_IPV4
   if (ip4_addr_isany(ip_2_ip4(&pcb->local_ip))) {
     /* use outgoing network interface IP address as source address */
-    src_ip = &netif->ip_addr;
+    src_ip = netif_ip_addr4(netif);
   } else {
     /* check if UDP PCB local IP address is correct
      * this could be an old address if netif->ip_addr has changed */