Add support for an in-memory routing table cache in order to improve performance when the routing table is retained in a file. The cache holds the most recently used routing table entries and so can eliminate some file access.

Squashed commit of the following:

    net/route:  Flush in cache when any entry is deleted from the routing table.  When a router matching an IP address is found, add the routing table entry to the cache.

    net/route:  Add utility functions to manage an in-memory cache to improve performance when use a file-based routing table.

net/route/Kconfig

@@ -65,6 +65,24 @@ config ROUTE_MAX_IPv4_RAMROUTES
 		eliminates dynamica memory allocations, but limits the maximum size
 		of the in-memory routing table to this number.
 
+config ROUTE_IPv4_CACHEROUTE
+	bool "In-memory IPv4 cache"
+	default n
+	depends on ROUTE_IPv4_FILEROUTE
+	---help---
+		Accessing a routing table on a file system before each packet is sent
+		can harm performance.  This option will cache a few of the most
+		frequently used routing table entries in memory to reduce performance
+		issues.
+
+config ROUTE_MAX_IPv4_CACHEROUTES
+	int "IPv4 cache size"
+	default 4
+	depends on ROUTE_IPv4_CACHEROUTE
+	---help---
+		This determines the maxium number of routes that can be cached in
+		memory.
+
 choice
 	prompt "IPv6 routing table"
 	default ROUTE_IPv6_RAMROUTE
@@ -125,5 +143,23 @@ config ROUTE_FILEDIR
 		table will be accessed.  This is a string and should not include
 		any traling '/'.
 
+config ROUTE_IPv6_CACHEROUTE
+	bool "In-memory IPv6 cache"
+	default n
+	depends on ROUTE_IPv6_FILEROUTE
+	---help---
+		Accessing a routing table on a file system before each packet is sent
+		can harm performance.  This option will cache a few of the most
+		frequently used routing table entries in memory to reduce performance
+		issues.
+
+config ROUTE_MAX_IPv6_CACHEROUTES
+	int "IPv6 cache size"
+	default 4
+	depends on ROUTE_IPv6_CACHEROUTE
+	---help---
+		This determines the maxium number of routes that can be cached in
+		memory.
+
 endif # NET_ROUTE
 endmenu # ARP Configuration

net/route/Make.defs

@@ -67,6 +67,14 @@ SOCK_CSRCS += net_fileroute.c net_add_fileroute.c net_del_fileroute.c
 SOCK_CSRCS += net_foreach_fileroute.c
 endif
 
+# In-memory cache for file-based routing tables
+
+ifeq ($(CONFIG_ROUTE_IPv4_CACHEROUTE),y)
+SOCK_CSRCS += net_cacheroute.c
+else ifeq ($(CONFIG_ROUTE_IPv6_CACHEROUTE),y)
+SOCK_CSRCS += net_cacheroute.c
+endif
+
 ifeq ($(CONFIG_DEBUG_NET_INFO),y)
 SOCK_CSRCS += net_dumproute.c
 endif

net/route/cacheroute.h

@@ -0,0 +1,143 @@
+/****************************************************************************
+ * net/route/cacheroute.h
+ *
+ *   Copyright (C) 2017 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.
+ *
+ ****************************************************************************/
+
+#ifndef __NET_ROUTE_CACHEROUTE_H
+#define __NET_ROUTE_CACHEROUTE_H 1
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include "route/route.h"
+
+#if defined(CONFIG_ROUTE_IPv4_CACHEROUTE) || defined(CONFIG_ROUTE_IPv6_CACHEROUTE)
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: net_init_cacheroute
+ *
+ * Description:
+ *   Initialize the in-memory, routing table cache
+ *
+ * Parameters:
+ *   None
+ *
+ * Returned Value:
+ *   None
+ *
+ * Assumptions:
+ *   Called early in initialization so that no special protection is needed.
+ *
+ ****************************************************************************/
+
+void net_init_cacheroute(void);
+
+/****************************************************************************
+ * Name: net_addcache_ipv4 and net_addcache_ipv6
+ *
+ * Description:
+ *   Add one route to the routing table cache
+ *
+ * Parameters:
+ *   None
+ *
+ * Returned Value:
+ *   Zero (OK) is returned on success; a negated errno value is returned
+ *   on any failure.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_ROUTE_IPv4_CACHEROUTE
+int net_addcache_ipv4(FAR struct net_route_ipv4_s *route);
+#endif
+
+#ifdef CONFIG_ROUTE_IPv6_CACHEROUTE
+int net_addcache_ipv6(FAR struct net_route_ipv6_s *route);
+#endif
+
+/****************************************************************************
+ * Name: net_foreachcache_ipv4/net_foreachcache_ipv6
+ *
+ * Description:
+ *   Traverse the routing table cahce
+ *
+ * Parameters:
+ *   handler - Will be called for each route in the routing table cache.
+ *   arg     - An arbitrary value that will be passed tot he handler.
+ *
+ * Returned Value:
+ *   Zero (OK) returned if the entire table was searched.  A negated errno
+ *   value will be returned in the event of a failure.  Handlers may also
+ *   terminate the search early with any non-zero value.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_ROUTE_IPv4_CACHEROUTE
+int net_foreachcache_ipv4(route_handler_ipv4_t handler, FAR void *arg);
+#endif
+
+#ifdef CONFIG_ROUTE_IPv6_CACHEROUTE
+int net_foreachcache_ipv6(route_handler_ipv6_t handler, FAR void *arg);
+#endif
+
+/****************************************************************************
+ * Name: net_flushcache_ipv4 and net_flushcache_ipv6
+ *
+ * Description:
+ *   Flush the content of the routing table cache
+ *
+ * Parameters:
+ *   None
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_ROUTE_IPv4_CACHEROUTE
+void net_flushcache_ipv4(void);
+#endif
+
+#ifdef CONFIG_ROUTE_IPv6_CACHEROUTE
+void net_flushcache_ipv6(void);
+#endif
+
+#endif /* CONFIG_ROUTE_IPv4_CACHEROUTE || CONFIG_ROUTE_IPv6_CACHEROUTE */
+#endif /* __NET_ROUTE_CACHEROUTE_H */

net/route/net_alloc_ramroute.c

@@ -124,7 +124,7 @@ void net_init_ramroute(void)
   ramroute_init(&g_ipv4_routes);
   ramroute_init(&g_free_ipv4routes);
 
-  /* All all of the pre-allocated routing table entries to a free list */
+  /* Add all of the pre-allocated routing table entries to a free list */
 
   for (i = 0; i < CONFIG_ROUTE_MAX_IPv4_RAMROUTES; i++)
     {
@@ -136,7 +136,7 @@ void net_init_ramroute(void)
   ramroute_init(&g_ipv6_routes);
   ramroute_init(&g_free_ipv6routes);
 
-  /* All all of the pre-allocated routing table entries to a free list */
+  /* Add all of the pre-allocated routing table entries to a free list */
 
   for (i = 0; i < CONFIG_ROUTE_MAX_IPv6_RAMROUTES; i++)
     {

net/route/net_del_fileroute.c

@@ -51,6 +51,7 @@
 #include <nuttx/net/ip.h>
 
 #include "route/fileroute.h"
+#include "route/cacheroute.h"
 #include "route/route.h"
 
 #if defined(CONFIG_ROUTE_IPv4_FILEROUTE) || defined(CONFIG_ROUTE_IPv6_FILEROUTE)
@@ -276,6 +277,14 @@ int net_delroute_ipv4(in_addr_t target, in_addr_t netmask)
        goto errout_with_lock;
     }
 
+#ifdef CONFIG_ROUTE_IPv4_CACHEROUTE
+  /* We are committed to modifying the routing table.  Flush the in-memory
+   * routing table cache.
+   */
+
+  net_flushcache_ipv4();
+#endif
+
   /* Loop, copying each entry, to the previous entry thus removing the entry
    * to be deleted.
    */
@@ -420,6 +429,14 @@ int net_delroute_ipv6(net_ipv6addr_t target, net_ipv6addr_t netmask)
       goto errout_with_lock;
     }
 
+#ifdef CONFIG_ROUTE_IPv6_CACHEROUTE
+  /* We are committed to modifying the routing table.  Flush the in-memory
+   * routing table cache.
+   */
+
+  net_flushcache_ipv6();
+#endif
+
   /* Loop, copying each entry, to the previous entry thus removing the entry
    * to be deleted.
    */

net/route/net_foreach_fileroute.c

@@ -73,7 +73,7 @@
  ****************************************************************************/
 
 #ifdef CONFIG_ROUTE_IPv4_FILEROUTE
-int net_foreachroute_ipv4(route_handler_t handler, FAR void *arg)
+int net_foreachroute_ipv4(route_handler_ipv4_t handler, FAR void *arg)
 {
   struct net_route_ipv4_s route;
   struct file fshandle;

net/route/net_foreach_ramroute.c

@@ -73,7 +73,7 @@
  ****************************************************************************/
 
 #ifdef CONFIG_ROUTE_IPv4_RAMROUTE
-int net_foreachroute_ipv4(route_handler_t handler, FAR void *arg)
+int net_foreachroute_ipv4(route_handler_ipv4_t handler, FAR void *arg)
 {
   FAR struct net_route_ipv4_entry_s *route;
   FAR struct net_route_ipv4_entry_s *next;

net/route/net_foreach_romroute.c

@@ -68,7 +68,7 @@
  ****************************************************************************/
 
 #ifdef CONFIG_ROUTE_IPv4_ROMROUTE
-int net_foreachroute_ipv4(route_handler_t handler, FAR void *arg)
+int net_foreachroute_ipv4(route_handler_ipv4_t handler, FAR void *arg)
 {
   int ret = 0;
   int i;

net/route/net_initroute.c

@@ -41,6 +41,7 @@
 
 #include "route/ramroute.h"
 #include "route/fileroute.h"
+#include "route/cacheroute.h"
 #include "route/route.h"
 
 #ifdef CONFIG_NET_ROUTE
@@ -72,6 +73,10 @@ void net_init_route(void)
 #if defined(CONFIG_ROUTE_IPv4_FILEROUTE) || defined(CONFIG_ROUTE_IPv6_FILEROUTE)
   net_init_fileroute();
 #endif
+
+#if defined(CONFIG_ROUTE_IPv4_CACHEROUTE) || defined(CONFIG_ROUTE_IPv6_CACHEROUTE)
+  net_init_cacheroute();
+#endif
 }
 
 #endif /* CONFIG_NET_ROUTE */

net/route/net_router.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * net/route/net_router.c
  *
- *   Copyright (C) 2013-2015 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2013-2015, 2017 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -48,10 +48,27 @@
 #include <nuttx/net/ip.h>
 
 #include "devif/devif.h"
+#include "route/cacheroute.h"
 #include "route/route.h"
 
 #if defined(CONFIG_NET) && defined(CONFIG_NET_ROUTE)
 
+/****************************************************************************
+ * Pre-processor defintions
+ ****************************************************************************/
+
+#ifdef CONFIG_ROUTE_IPv6_CACHEROUTE
+#  define IPv4_ROUTER entry.router
+#else
+#  define IPv4_ROUTER router
+#endif
+
+#ifdef CONFIG_ROUTE_IPv6_CACHEROUTE
+#  define IPv6_ROUTER entry.router
+#else
+#  define IPv6_ROUTER router
+#endif
+
 /****************************************************************************
  * Public Types
  ****************************************************************************/
@@ -59,16 +76,24 @@
 #ifdef CONFIG_NET_IPv4
 struct route_ipv4_match_s
 {
-  in_addr_t target;       /* Target IPv4 address on an external network to match */
-  in_addr_t router;       /* IPv4 address of the router on one of our networks */
+  in_addr_t target;              /* Target IPv4 address on remote network */
+#ifdef CONFIG_ROUTE_IPv4_CACHEROUTE
+  struct net_route_ipv4_s entry; /* Full entry from the IPv4 routing table */
+#else
+  in_addr_t router;              /* IPv4 address of router a local networks */
+#endif
 };
 #endif
 
 #ifdef CONFIG_NET_IPv6
 struct route_ipv6_match_s
 {
-  net_ipv6addr_t target;  /* Target IPv6 address on an external network to match */
-  net_ipv6addr_t router;  /* IPv6 address of the router on one of our networks */
+  net_ipv6addr_t target;         /* Target IPv6 address on remote network */
+#ifdef CONFIG_ROUTE_IPv6_CACHEROUTE
+  struct net_route_ipv6_s entry; /* Full entry from the IPv6 routing table */
+#else
+  net_ipv6addr_t router;         /* IPv6 address of router a local networks */
+#endif
 };
 #endif
 
@@ -103,9 +128,15 @@ static int net_ipv4_match(FAR struct net_route_ipv4_s *route, FAR void *arg)
 
   if (net_ipv4addr_maskcmp(route->target, match->target, route->netmask))
     {
+#ifdef CONFIG_ROUTE_IPv4_CACHEROUTE
+      /* They match.. Copy the entire routing table entry */
+
+      memcpy(&match->entry, route, sizeof(struct net_route_ipv4_s));
+#else
       /* They match.. Copy the router address */
 
       net_ipv4addr_copy(match->router, route->router);
+#endif
       return 1;
     }
 
@@ -140,9 +171,15 @@ static int net_ipv6_match(FAR struct net_route_ipv6_s *route, FAR void *arg)
 
   if (net_ipv6addr_maskcmp(route->target, match->target, route->netmask))
     {
+#ifdef CONFIG_ROUTE_IPv6_CACHEROUTE
+      /* They match.. Copy the entire routing table entry */
+
+      memcpy(&match->entry, route, sizeof(struct net_route_ipv6_s));
+#else
       /* They match.. Copy the router address */
 
       net_ipv6addr_copy(match->router, route->router);
+#endif
       return 1;
     }
 
@@ -189,23 +226,45 @@ int net_ipv4_router(in_addr_t target, FAR in_addr_t *router)
   memset(&match, 0, sizeof(struct route_ipv4_match_s));
   net_ipv4addr_copy(match.target, target);
 
-  /* Find an router entry with the routing table that can forward to this
-   * address
-   */
+#ifdef CONFIG_ROUTE_IPv4_CACHEROUTE
+  /* First see if we can find a router entry in the cache */
 
-  ret = net_foreachroute_ipv4(net_ipv4_match, &match);
+  ret = net_foreachcache_ipv4(net_ipv4_match, &match);
   if (ret > 0)
     {
       /* We found a route.  Return the router address. */
 
-      net_ipv4addr_copy(*router, match.router);
+      net_ipv4addr_copy(*router, match.IPv4_ROUTER);
       ret = OK;
     }
   else
+#endif
     {
-      /* There is no route for this address */
+      /* Find a router entry with the routing table that can forward to this
+       * address
+      */
 
-      ret = -ENOENT;
+      ret = net_foreachroute_ipv4(net_ipv4_match, &match);
+      if (ret > 0)
+        {
+          /* We found a route. */
+
+#ifdef CONFIG_ROUTE_IPv4_CACHEROUTE
+          /* Add the route to the cache */
+
+          ret = net_addcache_ipv4(&match.entry);
+#endif
+          /* Return the router address. */
+
+          net_ipv4addr_copy(*router, match.IPv4_ROUTER);
+          ret = OK;
+        }
+      else
+        {
+          /* There is no route for this address */
+
+          ret = -ENOENT;
+        }
     }
 
   return ret;
@@ -247,23 +306,45 @@ int net_ipv6_router(const net_ipv6addr_t target, net_ipv6addr_t router)
   memset(&match, 0, sizeof(struct route_ipv6_match_s));
   net_ipv6addr_copy(match.target, target);
 
-  /* Find an router entry with the routing table that can forward to this
-   * address
-   */
+#ifdef CONFIG_ROUTE_IPv6_CACHEROUTE
+  /* First see if we can find a router entry in the cache */
 
-  ret = net_foreachroute_ipv6(net_ipv6_match, &match);
+  ret = net_foreachcache_ipv6(net_ipv6_match, &match);
   if (ret > 0)
     {
       /* We found a route.  Return the router address. */
 
-      net_ipv6addr_copy(router, match.router);
+      net_ipv6addr_copy(router, match.IPv6_ROUTER);
       ret = OK;
     }
   else
+#endif
     {
-      /* There is no route for this address */
+      /* Find n router entry with the routing table that can forward to this
+       * address
+       */
 
-      ret = -ENOENT;
+      ret = net_foreachroute_ipv6(net_ipv6_match, &match);
+      if (ret > 0)
+        {
+          /* We found a route */
+
+#ifdef CONFIG_ROUTE_IPv6_CACHEROUTE
+          /* Add the route to the cache */
+
+          ret = net_addcache_ipv6(&match.entry);
+#endif
+          /* Return the router address. */
+
+          net_ipv6addr_copy(router, match.IPv6_ROUTER);
+          ret = OK;
+        }
+      else
+        {
+          /* There is no route for this address */
+
+          ret = -ENOENT;
+        }
     }
 
   return ret;

net/route/netdev_router.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * net/route/netdev_router.c
  *
- *   Copyright (C) 2013-2015 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2013-2015, 2017 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -47,10 +47,27 @@
 #include <nuttx/net/ip.h>
 
 #include "netdev/netdev.h"
+#include "route/cacheroute.h"
 #include "route/route.h"
 
 #if defined(CONFIG_NET) && defined(CONFIG_NET_ROUTE)
 
+/****************************************************************************
+ * Pre-processor defintions
+ ****************************************************************************/
+
+#ifdef CONFIG_ROUTE_IPv6_CACHEROUTE
+#  define IPv4_ROUTER entry.router
+#else
+#  define IPv4_ROUTER router
+#endif
+
+#ifdef CONFIG_ROUTE_IPv6_CACHEROUTE
+#  define IPv6_ROUTER entry.router
+#else
+#  define IPv6_ROUTER router
+#endif
+
 /****************************************************************************
  * Public Types
  ****************************************************************************/
@@ -58,18 +75,26 @@
 #ifdef CONFIG_NET_IPv4
 struct route_ipv4_devmatch_s
 {
-  FAR struct net_driver_s *dev; /* The route must use this device */
-  in_addr_t target;             /* Target IPv4 address on an external network to match */
-  in_addr_t router;             /* IPv6 address of the router on one of our networks */
+  FAR struct net_driver_s *dev;  /* The route must use this device */
+  in_addr_t target;              /* Target IPv4 address on remote network */
+#ifdef CONFIG_ROUTE_IPv4_CACHEROUTE
+  struct net_route_ipv4_s entry; /* Full entry from the IPv4 routing table */
+#else
+  in_addr_t router;              /* IPv4 address of router a local networks */
+#endif
 };
 #endif
 
 #ifdef CONFIG_NET_IPv6
 struct route_ipv6_devmatch_s
 {
-  FAR struct net_driver_s *dev; /* The route must use this device */
-  net_ipv6addr_t target;        /* Target IPv4 address on an external network to match */
-  net_ipv6addr_t router;        /* IPv6 address of the router on one of our networks */
+  FAR struct net_driver_s *dev;  /* The route must use this device */
+  net_ipv6addr_t target;         /* Target IPv4 address on remote network */
+#ifdef CONFIG_ROUTE_IPv6_CACHEROUTE
+  struct net_route_ipv6_s entry; /* Full entry from the IPv6 routing table */
+#else
+  net_ipv6addr_t router;         /* IPv6 address of router a local networks */
+#endif
 };
 #endif
 
@@ -110,9 +135,15 @@ static int net_ipv4_devmatch(FAR struct net_route_ipv4_s *route,
   if (net_ipv4addr_maskcmp(route->target, match->target, route->netmask) &&
       net_ipv4addr_maskcmp(route->router, dev->d_ipaddr, dev->d_netmask))
     {
+#ifdef CONFIG_ROUTE_IPv4_CACHEROUTE
+      /* They match.. Copy the entire routing table entry */
+
+      memcpy(&match->entry, route, sizeof(struct net_route_ipv4_s));
+#else
       /* They match.. Copy the router address */
 
       net_ipv4addr_copy(match->router, route->router);
+#endif
       return 1;
     }
 
@@ -154,9 +185,15 @@ static int net_ipv6_devmatch(FAR struct net_route_ipv6_s *route,
       net_ipv6addr_maskcmp(route->router, dev->d_ipv6addr,
                            dev->d_ipv6netmask))
     {
+#ifdef CONFIG_ROUTE_IPv6_CACHEROUTE
+      /* They match.. Copy the entire routing table entry */
+
+      memcpy(&match->entry, route, sizeof(struct net_route_ipv6_s));
+#else
       /* They match.. Copy the router address */
 
       net_ipv6addr_copy(match->router, route->router);
+#endif
       return 1;
     }
 
@@ -202,24 +239,46 @@ void netdev_ipv4_router(FAR struct net_driver_s *dev, in_addr_t target,
   match.dev = dev;
   net_ipv4addr_copy(match.target, target);
 
-  /* Find an router entry with the routing table that can forward to this
-   * address using this device.
-   */
+#ifdef CONFIG_ROUTE_IPv4_CACHEROUTE
+  /* First see if we can find a router entry in the cache */
 
-  ret = net_foreachroute_ipv4(net_ipv4_devmatch, &match);
+  ret = net_foreachcache_ipv4(net_ipv4_devmatch, &match);
   if (ret > 0)
     {
       /* We found a route.  Return the router address. */
 
-      net_ipv4addr_copy(*router, match.router);
+      net_ipv4addr_copy(*router, match.IPv4_ROUTER);
     }
   else
+#endif
     {
-      /* There isn't a matching route.. fallback and use the default router
-       * of the device.
+      /* Find a router entry with the routing table that can forward to this
+       * address using this device.
        */
 
-      net_ipv4addr_copy(*router, dev->d_draddr);
+      ret = net_foreachroute_ipv4(net_ipv4_devmatch, &match);
+      if (ret > 0)
+        {
+          /* We found a route */
+
+#ifdef CONFIG_ROUTE_IPv4_CACHEROUTE
+          /* Add the route to the cache */
+
+          ret = net_addcache_ipv4(&match.entry);
+#endif
+          /* We Return the router address. */
+
+          net_ipv4addr_copy(*router, match.IPv4_ROUTER);
+        }
+      else
+        {
+          /* There isn't a matching route.. fallback and use the default
+           * router
+           * of the device.
+           */
+
+          net_ipv4addr_copy(*router, dev->d_draddr);
+        }
     }
 }
 #endif
@@ -259,24 +318,45 @@ void netdev_ipv6_router(FAR struct net_driver_s *dev,
   match.dev = dev;
   net_ipv6addr_copy(match.target, target);
 
-  /* Find an router entry with the routing table that can forward to this
-   * address using this device.
-   */
+#ifdef CONFIG_ROUTE_IPv6_CACHEROUTE
+  /* First see if we can find a router entry in the cache */
 
-  ret = net_foreachroute_ipv6(net_ipv6_devmatch, &match);
+  ret = net_foreachcache_ipv6(net_ipv6_devmatch, &match);
   if (ret > 0)
     {
       /* We found a route.  Return the router address. */
 
-      net_ipv6addr_copy(router, match.router);
+      net_ipv6addr_copy(router, match.IPv6_ROUTER);
     }
   else
+#endif
     {
-      /* There isn't a matching route.. fallback and use the default router
-       * of the device.
+      /* Find a router entry with the routing table that can forward to this
+       * address using this device.
        */
 
-      net_ipv6addr_copy(router, dev->d_ipv6draddr);
+      ret = net_foreachroute_ipv6(net_ipv6_devmatch, &match);
+      if (ret > 0)
+        {
+          /* We found a route */
+
+#ifdef CONFIG_ROUTE_IPv6_CACHEROUTE
+          /* Add the route to the cache */
+
+          ret = net_addcache_ipv6(&match.entry);
+#endif
+          /* Return the router address. */
+
+          net_ipv6addr_copy(router, match.IPv6_ROUTER);
+       }
+      else
+        {
+          /* There isn't a matching route.. fallback and use the default
+           * router of the device.
+           */
+
+          net_ipv6addr_copy(router, dev->d_ipv6draddr);
+        }
     }
 }
 #endif

net/route/route.h

@@ -64,7 +64,7 @@ struct net_route_ipv4_s
 
 /* Type of the call out function pointer provided to net_foreachroute_ipv4() */
 
-typedef int (*route_handler_t)(FAR struct net_route_ipv4_s *route,
+typedef int (*route_handler_ipv4_t)(FAR struct net_route_ipv4_s *route,
                                FAR void *arg);
 #endif /* CONFIG_NET_IPv4 */
 
@@ -260,7 +260,7 @@ void netdev_ipv6_router(FAR struct net_driver_s *dev,
 #endif
 
 /****************************************************************************
- * Name: net_foreachroute_ipv4
+ * Name: net_foreachroute_ipv4/net_foreachroute_ipv6
  *
  * Description:
  *   Traverse the routing table
@@ -270,14 +270,14 @@ void netdev_ipv6_router(FAR struct net_driver_s *dev,
  *   arg     - An arbitrary value that will be passed tot he handler.
  *
  * Returned Value:
- *   Zero (OK) returned if the entire table was search.  A negated errno
+ *   Zero (OK) returned if the entire table was searched.  A negated errno
  *   value will be returned in the event of a failure.  Handlers may also
- *   terminate the search early with any non-zero, non-negative value.
+ *   terminate the search early with any non-zero value.
  *
  ****************************************************************************/
 
 #ifdef CONFIG_NET_IPv4
-int net_foreachroute_ipv4(route_handler_t handler, FAR void *arg);
+int net_foreachroute_ipv4(route_handler_ipv4_t handler, FAR void *arg);
 #endif
 
 #ifdef CONFIG_NET_IPv6