ICMPv6: Add logic to behave like a router (if so configured): NuttX will not send the router advertisement message in response to any router solicitation messages.

arch/arm/src/stm32/stm32_eth.c

@@ -3537,6 +3537,15 @@ static void stm32_ipv6multicast(FAR struct stm32_ethmac_s *priv)
   (void)stm32_addmac(dev, g_ipv6_ethallnodes.ether_addr_octet);
 
 #endif /* CONFIG_NET_ICMPv6_AUTOCONF */
+#ifdef CONFIG_NET_ICMPv6_ROUTER
+  /* Add the IPv6 all link-local routers Ethernet address.  This is the
+   * address that we expect to receive ICMPv6 Router Solicitation
+   * packets.
+   */
+
+  (void)stm32_addmac(dev, g_ipv6_ethallrouters.ether_addr_octet);
+
+#endif /* CONFIG_NET_ICMPv6_ROUTER */
 }
 #endif /* CONFIG_NET_ICMPv6 */
 

arch/arm/src/tiva/tm4c_ethernet.c

@@ -3995,6 +3995,15 @@ static void tiva_ipv6multicast(FAR struct tiva_ethmac_s *priv)
   (void)tiva_addmac(dev, g_ipv6_ethallnodes.ether_addr_octet);
 
 #endif /* CONFIG_NET_ICMPv6_AUTOCONF */
+#ifdef CONFIG_NET_ICMPv6_ROUTER
+  /* Add the IPv6 all link-local routers Ethernet address.  This is the
+   * address that we expect to receive ICMPv6 Router Solicitation
+   * packets.
+   */
+
+  (void)tiva_addmac(dev, g_ipv6_ethallrouters.ether_addr_octet);
+
+#endif /* CONFIG_NET_ICMPv6_ROUTER */
 }
 #endif /* CONFIG_NET_ICMPv6 */
 

net/icmpv6/icmpv6.h

@@ -273,6 +273,28 @@ void icmpv6_rsolicit(FAR struct net_driver_s *dev);
 void icmpv6_advertise(FAR struct net_driver_s *dev,
                       const net_ipv6addr_t destipaddr);
 
+/****************************************************************************
+ * Name: icmpv6_radvertise
+ *
+ * Description:
+ *   Send an ICMPv6 Router Advertisement
+ *
+ * Parameters:
+ *   dev - The device driver structure containing the outgoing ICMPv6 packet
+ *         buffer
+ *
+ * Return:
+ *   None
+ *
+ * Assumptions:
+ *   The network is locked
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_NET_ICMPv6_ROUTER
+void icmpv6_radvertise(FAR struct net_driver_s *dev);
+#endif
+
 /****************************************************************************
  * Function: icmpv6_wait_setup
  *

net/icmpv6/icmpv6_input.c

@@ -194,6 +194,23 @@ void icmpv6_input(FAR struct net_driver_s *dev)
       }
       break;
 
+#ifdef CONFIG_NET_ICMPv6_ROUTER
+    /* Check if we received a Router Solicitation */
+
+    case ICMPV6_ROUTER_SOLICIT:
+      {
+        /* Just give a knee-jerk Router Advertisement in respond with no
+         * further examination of the Router Solicitation.
+         */
+
+        icmpv6_radvertise(dev);
+
+        /* All statistics have been updated.  Nothing to do but exit. */
+
+        return;
+      }
+#endif
+
 #ifdef CONFIG_NET_ICMPv6_AUTOCONF
     /* Check if we received a Router Advertisement */