Broadcast IP route based on source IP address.

src/core/ipv4/ip4.c

@@ -121,9 +121,37 @@ ip4_set_default_multicast_netif(struct netif* default_multicast_netif)
 #endif /* LWIP_MULTICAST_TX_OPTIONS */
 
 #ifdef LWIP_HOOK_IP4_ROUTE_SRC
+#if ESP_LWIP
+/**
+ * Source based IPv4 routing hook function. This function works only
+ * when destination IP is broadcast IP.
+ */
+struct netif *
+ip4_route_src_hook(const ip4_addr_t *dest, const ip4_addr_t *src)
+{
+  struct netif *netif = NULL;
+
+  /* destination IP is broadcast IP? */
+  if ((src != NULL) && (!ip4_addr_isany(src) || dest->addr == IPADDR_BROADCAST)) {
+    /* iterate through netifs */
+    for (netif = netif_list; netif != NULL; netif = netif->next) {
+      /* is the netif up, does it have a link and a valid address? */
+      if (netif_is_up(netif) && netif_is_link_up(netif) && !ip4_addr_isany_val(*netif_ip4_addr(netif))) {
+        /* source IP matches? */
+        if (ip4_addr_cmp(src, netif_ip4_addr(netif))) {
+          /* return netif on which to forward IP packet */
+          return netif;
+        }
+      }
+    }
+  }
+  return netif;
+}
+#endif
+
 /**
  * Source based IPv4 routing must be fully implemented in
- * LWIP_HOOK_IP4_ROUTE_SRC(). This function only provides he parameters.
+ * LWIP_HOOK_IP4_ROUTE_SRC(). This function only provides the parameters.
  */
 struct netif *
 ip4_route_src(const ip4_addr_t *dest, const ip4_addr_t *src)