Another case where we should use the routing table: There may be multiple routers on the same network. In that case, we have to search for the routing table for the router that forwards to the destination address. We do this when we determine the MAC address we want in the ARP logic

1 files changed, 179 insertions, 0 deletions

diff --git a/nuttx/net/netdev_router.c b/nuttx/net/netdev_router.c
new file mode 100644
index 000000000..d1026cac5
--- /dev/null
+++ b/nuttx/net/netdev_router.c
@@ -0,0 +1,179 @@
+/****************************************************************************
+ * net/netdev_router.c
+ *
+ *   Copyright (C) 2013 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdint.h>
+#include <string.h>
+#include <errno.h>
+
+#include <nuttx/net/uip/uip-arch.h>
+
+#include "net_internal.h"
+#include "net_route.h"
+
+#if defined(CONFIG_NET) && defined(CONFIG_NET_ROUTE)
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+struct route_devmatch_s
+{
+  FAR struct uip_driver_s *dev; /* The route must use this device */
+  uip_ipaddr_t target;   /* The target IP address on an external network to match */
+  uip_ipaddr_t router;   /* The IP address of the router on one of our networks*/
+};
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function: net_devmatch
+ *
+ * Description:
+ *   Return 1 if the route is available on the device's network.
+ *
+ * Parameters:
+ *   route - The next route to examine
+ *   arg   - The match values (cast to void*)
+ *
+ * Returned Value:
+ *   0 if the entry is not a match; 1 if the entry matched and was cleared.
+ *
+ ****************************************************************************/
+
+static int net_devmatch(FAR struct net_route_s *route, FAR void *arg)
+{
+  FAR struct route_devmatch_s *match = (FAR struct route_devmatch_s *)arg;
+  FAR struct uip_driver_s *dev = match->dev;
+
+  /* To match, (1) the masked target addresses must be the same, and (2) the
+   * router address must like on the network provided by the device.
+   *
+   * In the event of multiple matches, only the first is returned.  There
+   * not (yet) any concept for the precedence of networks.
+   */
+
+  if (uip_ipaddr_maskcmp(route->target, match->target, route->netmask) &&
+      uip_ipaddr_maskcmp(route->router, dev->d_ipaddr, dev->d_netmask))
+    {
+      /* They match.. Copy the router address */
+
+      uip_ipaddr_copy(match->router, route->router);
+      return 1;
+    }
+
+  return 0;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function: netdev_router
+ *
+ * Description:
+ *   Given an IP address on a external network, return the address of the
+ *   router on a local network that can forward to the external network.
+ *   This is similar to net_router().  However, the set of routers is
+ *   constrained to those accessible by the specific device
+ *
+ * Parameters:
+ *   dev    - We are committed to using this device.
+ *   target - An IP address on a remote network to use in the lookup.
+ *   router - The address of router on a local network that can forward our
+ *     packets to the target.
+ *
+ *   NOTE:  For IPv6, router will be an array, for IPv4 it will be a scalar
+ *   value.  Hence, the change in the function signature.
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_NET_IPv6
+void netdev_router(FAR struct uip_driver_s *dev, uip_ipaddr_t target,
+                   uip_ipaddr_t router)
+#else
+void netdev_router(FAR struct uip_driver_s *dev, uip_ipaddr_t target,
+                   FAR uip_ipaddr_t *router)
+#endif
+{
+  struct route_devmatch_s match;
+  int ret;
+
+  /* Set up the comparison structure */
+
+  memset(&match, 0, sizeof(struct route_devmatch_s));
+  match.dev = dev;
+  uip_ipaddr_copy(match.target, target);
+
+  /* Then remove the entry from the routing table */
+
+  ret = net_foreachroute(net_devmatch, &match);
+  if (ret > 0)
+    {
+      /* We found a route.  Return the router address. */
+
+#ifdef CONFIG_NET_IPv6
+      uip_ipaddr_copy(router, match.target);
+#else
+      uip_ipaddr_copy(*router, match.target);
+#endif
+      ret = OK;
+    }
+  else
+    {
+      /* There isn't a matching route.. fallback and use the default router
+       * of the device.
+       */
+
+#ifdef CONFIG_NET_IPv6
+      uip_ipaddr_copy(router, dev->d_draddr);
+#else
+      uip_ipaddr_copy(*router, dev->d_draddr);
+#endif
+    }
+}
+
+#endif /* CONFIG_NET && CONFIG_NET_ROUTE */