Network: Add logic to get a default network device (for the case where are...

Network:  Add logic to get a default network device (for the case where are multiple devices).  For INADDR_ANY

net/netdev/Make.defs

@@ -38,7 +38,7 @@
 NETDEV_CSRCS += netdev_register.c netdev_ioctl.c netdev_txnotify.c
 NETDEV_CSRCS += netdev_findbyname.c netdev_findbyaddr.c netdev_count.c
 NETDEV_CSRCS += netdev_foreach.c netdev_unregister.c netdev_sem.c
-NETDEV_CSRCS += netdev_carrier.c
+NETDEV_CSRCS += netdev_carrier.c netdev_default.c
 
 ifeq ($(CONFIG_NET_RXAVAIL),y)
 NETDEV_CSRCS += netdev_rxnotify.c

net/netdev/netdev.h

@@ -97,6 +97,12 @@ FAR struct net_driver_s *netdev_findbyname(FAR const char *ifname);
 FAR struct net_driver_s *netdev_findbyaddr(const net_ipaddr_t addr);
 #endif
 
+/* netdev_default.c ***********************************************************/
+
+#if CONFIG_NSOCKET_DESCRIPTORS > 0
+FAR struct net_driver_s *netdev_default(void);
+#endif
+
 /* netdev_txnotify.c *********************************************************/
 
 #if CONFIG_NSOCKET_DESCRIPTORS > 0
@@ -111,7 +117,7 @@ void netdev_rxnotify(const net_ipaddr_t addr);
 #  define netdev_rxnotify(addr)
 #endif
 
-/* net_count.c ***************************************************************/
+/* netdev_count.c ************************************************************/
 
 #if CONFIG_NSOCKET_DESCRIPTORS > 0
 int netdev_count(void);

net/netdev/netdev_default.c

+/****************************************************************************
+ * net/netdev/netdev_default.c
+ *
+ *   Copyright (C) 2014 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>
+#if defined(CONFIG_NET) && CONFIG_NSOCKET_DESCRIPTORS > 0
+
+#include <nuttx/net/netdev.h>
+#include "netdev/netdev.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function: netdev_maskcmp
+ ****************************************************************************/
+
+/****************************************************************************
+ * Global Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function: netdev_default
+ *
+ * Description:
+ *   Return the default network device.  REVISIT:  At present this function
+ *   arbitrarily returns the first UP device at the head of the device
+ *   list.  Perhaps the default device should be a device name
+ *   configuration option?
+ *
+ *   So why is this here:  It represents my current though for what to do
+ *   if a socket is connected with INADDY_ANY.  In this case, I suppose we
+ *   should use the IP address associated with some default device???
+ *
+ * Parameters:
+ *   NULL
+ *
+ * Returned Value:
+ *  Pointer to default network driver on success; null on failure
+ *
+ * Assumptions:
+ *  Called from normal user mode
+ *
+ ****************************************************************************/
+
+FAR struct net_driver_s *netdev_default(void)
+{
+  FAR struct net_driver_s *dev;
+
+  /* Examine each registered network device */
+
+  netdev_semtake();
+  for (dev = g_netdevices; dev; dev = dev->flink)
+    {
+      /* Is the interface in the "up" state? */
+
+      if ((dev->d_flags & IFF_UP) != 0)
+        {
+          /* Return a reference to the first device we find that is in the UP
+           * state.
+           */
+
+          netdev_semgive();
+          return dev;
+        }
+    }
+
+  netdev_semgive();
+  return NULL;
+}
+
+#endif /* CONFIG_NET  */

net/netdev/netdev_findbyaddr.c

@@ -96,7 +96,7 @@
 
 static FAR struct net_driver_s *netdev_finddevice(const net_ipaddr_t addr)
 {
-  struct net_driver_s *dev;
+  FAR struct net_driver_s *dev;
 
   /* Examine each registered network device */
 

net/netdev/netdev_findbyname.c

@@ -103,8 +103,10 @@ FAR struct net_driver_s *netdev_findbyname(const char *ifname)
               return dev;
             }
         }
+
       netdev_semgive();
     }
+
   return NULL;
 }