net/arp: Redesign ARP table aging to simplify the net initialization

include/nuttx/net/arp.h

@@ -83,7 +83,7 @@ struct arp_entry_s
 {
   in_addr_t         at_ipaddr;   /* IP address */
   struct ether_addr at_ethaddr;  /* Hardware address */
-  uint8_t           at_time;     /* Time of last usage */
+  clock_t           at_time;     /* Time of last usage */
 };
 
 /* Used with the SIOCSARP, SIOCDARP, and SIOCGARP IOCTL commands to set,

include/nuttx/net/net.h

@@ -256,7 +256,7 @@ extern "C"
  ****************************************************************************/
 
 /****************************************************************************
- * Name: net_setup
+ * Name: net_initialize
  *
  * Description:
  *   This is called from the OS initialization logic at power-up reset in
@@ -278,25 +278,6 @@ extern "C"
  *
  ****************************************************************************/
 
-void net_setup(void);
-
-/****************************************************************************
- * Name: net_initialize
- *
- * Description:
- *   This function is called from the OS initialization logic at power-up
- *   reset AFTER initialization of hardware facilities such as timers and
- *   interrupts.   This logic completes the initialization started by
- *   net_setup().
- *
- * Input Parameters:
- *   None
- *
- * Returned Value:
- *   None
- *
- ****************************************************************************/
-
 void net_initialize(void);
 
 /****************************************************************************

net/arp/Make.defs

@@ -36,7 +36,7 @@
 # ARP support is available for Ethernet only
 
 ifeq ($(CONFIG_NET_ARP),y)
-NET_CSRCS += arp_arpin.c arp_out.c arp_format.c arp_table.c arp_timer.c
+NET_CSRCS += arp_arpin.c arp_out.c arp_format.c arp_table.c
 
 ifeq ($(CONFIG_NET_ARP_IPIN),y)
 NET_CSRCS += arp_ipin.c

net/arp/arp.h

@@ -176,49 +176,6 @@ struct arp_notify_s
  ****************************************************************************/
 
 #ifdef CONFIG_NET_ARP
-/****************************************************************************
- * Name: arp_reset
- *
- * Description:
- *   Re-initialize the ARP table.
- *
- ****************************************************************************/
-
-void arp_reset(void);
-
-/****************************************************************************
- * Name: arp_timer_initialize
- *
- * Description:
- *   Initialized the 10 second timer that is need by the ARP logic in order
- *   to age ARP address associations
- *
- * Input Parameters:
- *   None
- *
- * Returned Value:
- *   None
- *
- * Assumptions:
- *   Called once at system initialization time
- *
- ****************************************************************************/
-
-void arp_timer_initialize(void);
-
-/****************************************************************************
- * Name: arp_timer
- *
- * Description:
- *   This function performs periodic timer processing in the ARP module
- *   and should be called at regular intervals.  The recommended interval
- *   is 10 seconds between the calls.  It is responsible for flushing old
- *   entries in the ARP table.
- *
- ****************************************************************************/
-
-void arp_timer(void);
-
 /****************************************************************************
  * Name: arp_format
  *
@@ -492,9 +449,6 @@ void arp_dump(FAR struct arp_hdr_s *arp);
 
 /* If ARP is disabled, stub out all ARP interfaces */
 
-#  define arp_reset()
-#  define arp_timer_initialize()
-#  define arp_timer()
 #  define arp_format(d,i);
 #  define arp_send(i) (0)
 #  define arp_poll(d,c) (0)

net/arp/arp_table.c

@@ -54,6 +54,7 @@
 #include <netinet/in.h>
 #include <net/ethernet.h>
 
+#include <nuttx/clock.h>
 #include <nuttx/net/netconfig.h>
 #include <nuttx/net/net.h>
 #include <nuttx/net/netdev.h>
@@ -65,6 +66,12 @@
 
 #ifdef CONFIG_NET_ARP
 
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#define ARP_MAXAGE_TICK SEC2TICK(10 * CONFIG_NET_ARP_MAXAGE)
+
 /****************************************************************************
  * Private Types
  ****************************************************************************/
@@ -82,7 +89,6 @@ struct arp_table_info_s
 /* The table of known address mappings */
 
 static struct arp_entry_s g_arptable[CONFIG_NET_ARPTAB_SIZE];
-static uint8_t g_arptime;
 
 /****************************************************************************
  * Private Functions
@@ -134,57 +140,40 @@ static int arp_match(FAR struct net_driver_s *dev, FAR void *arg)
   return 1;
 }
 
+
+/****************************************************************************
+ * Name: arp_return_old_entry
+ *
+ * Description:
+ *   Compare and return the old ARP table entry.
+ *
+ ****************************************************************************/
+
+static FAR struct arp_entry_s *
+arp_return_old_entry(FAR struct arp_entry_s *e1, FAR struct arp_entry_s *e2)
+{
+  if (e1->at_ipaddr == 0)
+    {
+      return e1;
+    }
+  else if (e2->at_ipaddr == 0)
+    {
+      return e2;
+    }
+  else if ((int)(e1->at_time - e2->at_time) <= 0)
+    {
+      return e1;
+    }
+  else
+    {
+      return e2;
+    }
+}
+
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
 
-/****************************************************************************
- * Name: arp_reset
- *
- * Description:
- *   Re-initialize the ARP table.
- *
- ****************************************************************************/
-
-void arp_reset(void)
-{
-  int i;
-
-  for (i = 0; i < CONFIG_NET_ARPTAB_SIZE; ++i)
-    {
-      memset(&g_arptable[i].at_ipaddr, 0, sizeof(in_addr_t));
-    }
-}
-
-/****************************************************************************
- * Name: arp_timer
- *
- * Description:
- *   This function performs periodic timer processing in the ARP module
- *   and should be called at regular intervals. The recommended interval
- *   is 10 seconds between the calls.  It is responsible for flushing old
- *   entries in the ARP table.
- *
- ****************************************************************************/
-
-void arp_timer(void)
-{
-  FAR struct arp_entry_s *tabptr;
-  int i;
-
-  ++g_arptime;
-  for (i = 0; i < CONFIG_NET_ARPTAB_SIZE; ++i)
-    {
-      tabptr = &g_arptable[i];
-
-      if (tabptr->at_ipaddr != 0 &&
-          g_arptime - tabptr->at_time >= CONFIG_NET_ARP_MAXAGE)
-        {
-          tabptr->at_ipaddr = 0;
-        }
-    }
-}
-
 /****************************************************************************
  * Name: arp_update
  *
@@ -207,8 +196,8 @@ void arp_timer(void)
 
 int arp_update(in_addr_t ipaddr, FAR uint8_t *ethaddr)
 {
-  struct arp_entry_s *tabptr = NULL;
+  FAR struct arp_entry_s *tabptr = &g_arptable[0];
-  int               i;
+  int i;
 
   /* Walk through the ARP mapping table and try to find an entry to
    * update. If none is found, the IP -> MAC address mapping is
@@ -217,69 +206,33 @@ int arp_update(in_addr_t ipaddr, FAR uint8_t *ethaddr)
 
   for (i = 0; i < CONFIG_NET_ARPTAB_SIZE; ++i)
     {
-      tabptr = &g_arptable[i];
+      /* Check if the source IP address of the incoming packet matches
+       * the IP address in this ARP table entry.
+       */
 
-      /* Only check those entries that are actually in use. */
+      if (g_arptable[i].at_ipaddr != 0 &&
-
+          net_ipv4addr_cmp(ipaddr, g_arptable[i].at_ipaddr))
-      if (tabptr->at_ipaddr != 0)
         {
-          /* Check if the source IP address of the incoming packet matches
+          /* An old entry found, break. */
-           * the IP address in this ARP table entry.
-           */
 
-          if (net_ipv4addr_cmp(ipaddr, tabptr->at_ipaddr))
+          tabptr = &g_arptable[i];
-            {
-              /* An old entry found, update this and return. */
-
-              memcpy(tabptr->at_ethaddr.ether_addr_octet, ethaddr, ETHER_ADDR_LEN);
-              tabptr->at_time = g_arptime;
-              return OK;
-            }
-        }
-    }
-
-  /* If we get here, no existing ARP table entry was found, so we create one. */
-  /* First, we try to find an unused entry in the ARP table. */
-
-  for (i = 0; i < CONFIG_NET_ARPTAB_SIZE; ++i)
-    {
-      tabptr = &g_arptable[i];
-      if (tabptr->at_ipaddr == 0)
-        {
           break;
         }
-    }
+      else
-
-  /* If no unused entry is found, we try to find the oldest entry and
-   * throw it away.
-   */
-
-  if (i == CONFIG_NET_ARPTAB_SIZE)
-    {
-      uint8_t tmpage = 0;
-      int j = 0;
-
-      for (i = 0; i < CONFIG_NET_ARPTAB_SIZE; ++i)
         {
-          tabptr = &g_arptable[i];
+          /* Record the oldest entry. */
-          if (g_arptime - tabptr->at_time > tmpage)
-            {
-              tmpage = g_arptime - tabptr->at_time;
-              j = i;
-            }
-        }
 
-      i = j;
+          tabptr = arp_return_old_entry(tabptr, &g_arptable[i]);
-      tabptr = &g_arptable[i];
+        }
     }
 
-  /* Now, i is the ARP table entry which we will fill with the new
+  /* Now, tabptr is the ARP table entry which we will fill with the new
    * information.
    */
 
   tabptr->at_ipaddr = ipaddr;
   memcpy(tabptr->at_ethaddr.ether_addr_octet, ethaddr, ETHER_ADDR_LEN);
-  tabptr->at_time = g_arptime;
+  tabptr->at_time = clock_systimer();
   return OK;
 }
 
@@ -337,7 +290,8 @@ FAR struct arp_entry_s *arp_lookup(in_addr_t ipaddr)
   for (i = 0; i < CONFIG_NET_ARPTAB_SIZE; ++i)
     {
       tabptr = &g_arptable[i];
-      if (net_ipv4addr_cmp(ipaddr, tabptr->at_ipaddr))
+      if (net_ipv4addr_cmp(ipaddr, tabptr->at_ipaddr) &&
+          clock_systimer() - tabptr->at_time <= ARP_MAXAGE_TICK)
         {
           return tabptr;
         }
@@ -442,3 +396,4 @@ void arp_delete(in_addr_t ipaddr)
 
 #endif /* CONFIG_NET_ARP */
 #endif /* CONFIG_NET */
+

net/arp/arp_timer.c

@@ -1,133 +0,0 @@
-/****************************************************************************
- * net/arp/arp_timer.c
- *
- *   Copyright (C) 2007-2009, 2011, 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>
-#ifdef CONFIG_NET
-
-#include <stdint.h>
-#include <time.h>
-#include <debug.h>
-
-#include <nuttx/wdog.h>
-#include <nuttx/net/netconfig.h>
-
-#include <arp/arp.h>
-
-#ifdef CONFIG_NET_ARP
-
-/****************************************************************************
- * Pre-processor Definitions
- ****************************************************************************/
-
-/* ARP timer interval = 10 seconds. CLK_TCK is the number of clock ticks
- * per second
- */
-
-#define ARPTIMER_WDINTERVAL (10*CLK_TCK)
-
-/****************************************************************************
- * Private Data
- ****************************************************************************/
-
-static WDOG_ID g_arptimer;           /* ARP timer */
-
-/****************************************************************************
- * Private Functions
- ****************************************************************************/
-
-/****************************************************************************
- * Name: arptimer_poll
- *
- * Description:
- *   Periodic timer handler.  Called from the timer interrupt handler.
- *
- * Input Parameters:
- *   argc - The number of available arguments
- *   arg  - The first argument
- *
- * Returned Value:
- *   None
- *
- * Assumptions:
- *
- ****************************************************************************/
-
-static void arptimer_poll(int argc, wdparm_t arg, ...)
-{
-  /* Call the ARP timer function every 10 seconds. */
-
-  arp_timer();
-
-  /* Setup the watchdog timer again */
-
-  (void)wd_start(g_arptimer, ARPTIMER_WDINTERVAL, arptimer_poll, 0);
-}
-
-/****************************************************************************
- * Public Functions
- ****************************************************************************/
-
-/****************************************************************************
- * Name: arp_timer_initialize
- *
- * Description:
- *   Initialized the 10 second timer that is need by the ARP logic in order
- *   to age ARP address associations
- *
- * Input Parameters:
- *   None
- *
- * Returned Value:
- *   None
- *
- * Assumptions:
- *   Called once at system initialization time
- *
- ****************************************************************************/
-
-void arp_timer_initialize(void)
-{
-  /* Create and start the ARP timer */
-
-  g_arptimer = wd_create();
-  (void)wd_start(g_arptimer, ARPTIMER_WDINTERVAL, arptimer_poll, 0);
-}
-
-#endif /* CONFIG_NET_ARP */
-#endif /* CONFIG_NET */

net/net_initialize.c

@@ -49,7 +49,6 @@
 #include "devif/devif.h"
 #include "netdev/netdev.h"
 #include "ipforward/ipforward.h"
-#include "arp/arp.h"
 #include "sixlowpan/sixlowpan.h"
 #include "neighbor/neighbor.h"
 #include "icmp/icmp.h"
@@ -72,7 +71,7 @@
  ****************************************************************************/
 
 /****************************************************************************
- * Name: net_setup
+ * Name: net_initialize
  *
  * Description:
  *   This is called from the OS initialization logic at power-up reset in
@@ -94,16 +93,12 @@
  *
  ****************************************************************************/
 
-void net_setup(void)
+void net_initialize(void)
 {
   /* Initialize the locking facility */
 
   net_lockinitialize();
 
-  /* Clear the ARP table */
-
-  arp_reset();
-
 #ifdef CONFIG_NET_IPv6
   /* Initialize the Neighbor Table data structures */
 
@@ -219,28 +214,4 @@ void net_setup(void)
 #endif
 }
 
-/****************************************************************************
- * Name: net_initialize
- *
- * Description:
- *   This function is called from the OS initialization logic at power-up
- *   reset AFTER initialization of hardware facilities such as timers and
- *   interrupts.   This logic completes the initialization started by
- *   net_setup().
- *
- * Input Parameters:
- *   None
- *
- * Returned Value:
- *   None
- *
- ****************************************************************************/
-
-void net_initialize(void)
-{
-  /* Initialize the periodic ARP timer */
-
-  arp_timer_initialize();
-}
-
 #endif /* CONFIG_NET */

sched/init/os_start.c

@@ -68,9 +68,6 @@
 #ifndef CONFIG_DISABLE_PTHREAD
 #  include "pthread/pthread.h"
 #endif
-#ifdef CONFIG_SCHED_WORKQUEUE
-#  include "wqueue/wqueue.h"
-#endif
 #include "clock/clock.h"
 #include "timer/timer.h"
 #include "irq/irq.h"
@@ -694,15 +691,9 @@ void os_start(void)
 #endif
 
 #ifdef CONFIG_NET
-  /* Initialize the networking system.  Network initialization is
+  /* Initialize the networking system */
-   * performed in two steps:  (1) net_setup() initializes static
-   * configuration of the network support.  This must be done prior
-   * to registering network drivers by up_initialize().  This step
-   * cannot require upon any hardware-depending features such as
-   * timers or interrupts.
-   */
 
-  net_setup();
+  net_initialize();
 #endif
 
   /* The processor specific details of running the operating system
@@ -717,14 +708,6 @@ void os_start(void)
 
   g_os_initstate = OSINIT_HARDWARE;
 
-#ifdef CONFIG_NET
-  /* Complete initialization the networking system now that interrupts
-   * and timers have been configured by up_initialize().
-   */
-
-  net_initialize();
-#endif
-
 #ifdef CONFIG_MM_SHM
   /* Initialize shared memory support */