Merge branch 'feature/ip_route_base_on_source_ip' into 'master'

Broadcast IP route based on source IP address.

See merge request !942

components/lwip/core/ipv4/ip4.c

@@ -115,9 +115,36 @@ ip4_set_default_multicast_netif(struct netif* default_multicast_netif)
 #endif /* LWIP_MULTICAST_TX_OPTIONS */
 
 #ifdef LWIP_HOOK_IP4_ROUTE_SRC
+/**
+ * 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) && (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;
+}
+
 /**
  * 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)

components/lwip/include/lwip/port/lwipopts.h

@@ -596,6 +596,7 @@
    ---------- Hook options ---------------
    ---------------------------------------
 */
+#define LWIP_HOOK_IP4_ROUTE_SRC         ip4_route_src_hook
 
 /*
    ---------------------------------------