Merged in antmerlino/nuttx/sixlowpan-route (pull request #537)

sixlowpan: Support sending to a router that is on-link and may be able to forward the packet for us if the destination is not reachable directly

Approved-by: Gregory Nutt <gnutt@nuttx.org>

net/sixlowpan/sixlowpan_icmpv6send.c

@@ -114,15 +114,13 @@ void sixlowpan_icmpv6_send(FAR struct net_driver_s *dev,
           uint16_t buflen;
           int ret;
 
-          /* Get the IEEE 802.15.4 MAC address of the destination.  This
+          /* Get the IEEE 802.15.4 MAC address of the next hop. */
-           * assumes an encoding of the MAC address in the IPv6 address.
-           */
 
-          ret = sixlowpan_destaddrfromip((FAR struct radio_driver_s *)fwddev,
+          ret = sixlowpan_nexthopaddr((FAR struct radio_driver_s *)fwddev,
                                       ipv6icmpv6->ipv6.destipaddr, &destmac);
           if (ret < 0)
             {
-              nerr("ERROR: Failed to dest MAC address: %d\n", ret);
+              nerr("ERROR: Failed to get dest MAC address: %d\n", ret);
               goto drop;
             }
 

net/sixlowpan/sixlowpan_input.c

@@ -782,11 +782,11 @@ int sixlowpan_input(FAR struct radio_driver_s *radio,
                    * address.
                    */
 
-                  ret = sixlowpan_destaddrfromip(radio, ipv6hdr->destipaddr,
+                  ret = sixlowpan_nexthopaddr(radio, ipv6hdr->destipaddr,
                                               &destmac);
                   if (ret < 0)
                     {
-                      nerr("ERROR: Failed to dest MAC address: %d\n", ret);
+                      nerr("ERROR: Failed to get dest MAC address: %d\n", ret);
                       goto drop;
                     }
 

net/sixlowpan/sixlowpan_internal.h

@@ -564,6 +564,22 @@ int sixlowpan_uncompresshdr_hc1(FAR struct radio_driver_s *radio,
                                 FAR uint8_t *bptr);
 #endif
 
+/****************************************************************************
+ * Name: sixlowpan_nexthopaddr
+ *
+ * Description:
+ *   sixlowpan_nexthopaddr(): If the destination is on-link, extract the
+ *   IEEE 802.15.14 destination address from the destination IP address. If the
+ *   destination is not reachable directly, use the routing table (if available)
+ *   or fall back to the default router IP address and use the router IP address
+ *   to derive the IEEE 802.15.4 MAC address.
+ *
+ ****************************************************************************/
+
+int sixlowpan_nexthopaddr(FAR struct radio_driver_s *radio,
+                          FAR const net_ipv6addr_t ipaddr,
+                          FAR struct netdev_varaddr_s *destaddr);
+
 /****************************************************************************
  * Name: sixlowpan_islinklocal, sixlowpan_destaddrfromip, and
  *       sixlowpan_ismacbased

net/sixlowpan/sixlowpan_tcpsend.c

@@ -838,11 +838,9 @@ ssize_t psock_6lowpan_tcp_send(FAR struct socket *psock, FAR const void *buf,
     }
 #endif
 
-  /* Get the IEEE 802.15.4 MAC address of the destination.  This assumes
+  /* Get the IEEE 802.15.4 MAC address of the next hop. */
-   * an encoding of the MAC address in the IPv6 address.
-   */
 
-  ret = sixlowpan_destaddrfromip((FAR struct radio_driver_s *)dev,
+  ret = sixlowpan_nexthopaddr((FAR struct radio_driver_s *)dev,
                               conn->u.ipv6.raddr, &destmac);
   if (ret < 0)
     {
@@ -957,11 +955,9 @@ void sixlowpan_tcp_send(FAR struct net_driver_s *dev,
           uint16_t buflen;
           int ret;
 
-          /* Get the IEEE 802.15.4 MAC address of the destination.  This
+          /* Get the IEEE 802.15.4 MAC address of the next hop. */
-           * assumes an encoding of the MAC address in the IPv6 address.
-           */
 
-          ret = sixlowpan_destaddrfromip((FAR struct radio_driver_s *)fwddev,
+          ret = sixlowpan_nexthopaddr((FAR struct radio_driver_s *)fwddev,
                                       ipv6hdr->ipv6.destipaddr, &destmac);
           if (ret < 0)
             {

net/sixlowpan/sixlowpan_udpsend.c

@@ -292,11 +292,9 @@ ssize_t psock_6lowpan_udp_sendto(FAR struct socket *psock,
   g_netstats.udp.sent++;
 #endif
 
-  /* Get the IEEE 802.15.4 MAC address of the destination  This assumes an
+  /* Get the IEEE 802.15.4 MAC address of the next hop. */
-   * encoding of the MAC address in the IPv6 address.
-   */
 
-  ret = sixlowpan_destaddrfromip((FAR struct radio_driver_s *)dev,
+  ret = sixlowpan_nexthopaddr((FAR struct radio_driver_s *)dev,
                               to6->sin6_addr.in6_u.u6_addr16, &destmac);
   if (ret < 0)
     {
@@ -468,11 +466,9 @@ void sixlowpan_udp_send(FAR struct net_driver_s *dev,
           uint16_t buflen;
           int ret;
 
-          /* Get the IEEE 802.15.4 MAC address of the destination.  This
+          /* Get the IEEE 802.15.4 MAC address of the next hop. */
-           * assumes an encoding of the MAC address in the IPv6 address.
-           */
 
-          ret = sixlowpan_destaddrfromip((FAR struct radio_driver_s *)fwddev,
+          ret = sixlowpan_nexthopaddr((FAR struct radio_driver_s *)fwddev,
                                       ipv6udp->ipv6.destipaddr, &destmac);
           if (ret < 0)
             {

net/sixlowpan/sixlowpan_utils.c

@@ -166,6 +166,63 @@ static void sixlowpan_eaddrfromip(const net_ipv6addr_t ipaddr, FAR uint8_t *eadd
  * Public Functions
  ****************************************************************************/
 
+/****************************************************************************
+ * Name: sixlowpan_nexthopaddr
+ *
+ * Description:
+ *   sixlowpan_nexthopaddr(): If the destination is on-link, extract the
+ *   IEEE 802.15.14 destination address from the destination IP address. If the
+ *   destination is not reachable directly, use the routing table (if available)
+ *   or fall back to the default router IP address and use the router IP address
+ *   to derive the IEEE 802.15.4 MAC address.
+ *
+ ****************************************************************************/
+
+int sixlowpan_nexthopaddr(FAR struct radio_driver_s *radio,
+                          FAR const net_ipv6addr_t ipaddr,
+                          FAR struct netdev_varaddr_s *destaddr)
+{
+  FAR net_ipv6addr_t router;
+  int ret;
+
+  /* Try to get the IEEE 802.15.4 MAC address of the destination.  This
+   * assumes an encoding of the MAC address in the IPv6 address.
+   */
+
+  ret = sixlowpan_destaddrfromip(radio, ipaddr, destaddr);
+  if (ret < 0)
+    {
+      /* Destination address is not on the local network */
+
+#ifdef CONFIG_NET_ROUTE
+      /* We have a routing table.. find the correct router to use in
+       * this case (or, as a fall-back, use the device's default router
+       * address).  We will use the router IPv6 address instead of the
+       * destination address when determining the MAC address.
+       */
+
+      netdev_ipv6_router(radio->r_dev, ipaddr, router);
+#else
+      /* Use the device's default router IPv6 address instead of the
+       * destination address when determining the MAC address.
+       */
+
+      net_ipv6addr_copy(router, radio->r_dev.d_ipv6draddr);
+#endif
+      /* Get the IEEE 802.15.4 MAC address of the router.  This
+       * assumes an encoding of the MAC address in the IPv6 address.
+       */
+
+      ret = sixlowpan_destaddrfromip(radio, router, destaddr);
+      if (ret < 0)
+        {
+          return ret;
+        }
+    }
+
+  return OK;
+}
+
 /****************************************************************************
  * Name: sixlowpan_destaddrfromip
  *