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+/****************************************************************************
+ * net/uip/uip_arptab.c
+ * Implementation of the ARP Address Resolution Protocol.
+ *
+ * Copyright (C) 2007-2009 Gregory Nutt. All rights reserved.
+ * Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Based originally on uIP which also has a BSD style license:
+ *
+ * Author: Adam Dunkels <adam@dunkels.com>
+ * Copyright (c) 2001-2003, Adam Dunkels.
+ * All rights reserved.
+ *
+ * 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. The name of the author may not be used to endorse or promote
+ * products derived from this software without specific prior
+ * written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 <sys/types.h>
+#include <sys/ioctl.h>
+
+#include <string.h>
+#include <debug.h>
+
+#include <netinet/in.h>
+#include <net/ethernet.h>
+#include <net/uip/uip-arch.h>
+#include <net/uip/uip-arp.h>
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/* The table of known address mappings */
+
+static struct arp_entry g_arptable[CONFIG_NET_ARPTAB_SIZE];
+static uint8 g_arptime;
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: uip_arp_init
+ *
+ * Description:
+ * Initialize the ARP module. This function must be called before any of
+ * the other ARP functions.
+ *
+ ****************************************************************************/
+
+void uip_arp_init(void)
+{
+ int i;
+ for (i = 0; i < CONFIG_NET_ARPTAB_SIZE; ++i)
+ {
+ memset(&g_arptable[i].at_ipaddr, 0, sizeof(in_addr_t));
+ }
+}
+
+/****************************************************************************
+ * Name: uip_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 uip_arp_timer(void)
+{
+ struct arp_entry *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 >= UIP_ARP_MAXAGE)
+ {
+ tabptr->at_ipaddr = 0;
+ }
+ }
+}
+
+/****************************************************************************
+ * Name: uip_arp_update
+ *
+ * Description:
+ * Add the IP/HW address mapping to the ARP table -OR- change the IP
+ * address of an existing association.
+ *
+ * Input parameters:
+ * pipaddr - Refers to an IP address uint16[2]
+ * ethaddr - Refers to a HW address uint8[IFHWADDRLEN]
+ *
+ * Assumptions
+ * Interrupts are disabled
+ *
+ ****************************************************************************/
+
+void uip_arp_update(uint16 *pipaddr, uint8 *ethaddr)
+{
+ struct arp_entry *tabptr = NULL;
+ in_addr_t ipaddr = uip_ip4addr_conv(pipaddr);
+ 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
+ * inserted in the ARP table.
+ */
+
+ for (i = 0; i < CONFIG_NET_ARPTAB_SIZE; ++i)
+ {
+ tabptr = &g_arptable[i];
+
+ /* Only check those entries that are actually in use. */
+
+ if (tabptr->at_ipaddr != 0)
+ {
+ /* Check if the source IP address of the incoming packet matches
+ * the IP address in this ARP table entry.
+ */
+
+ if (uip_ipaddr_cmp(ipaddr, tabptr->at_ipaddr))
+ {
+ /* 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;
+ }
+ }
+ }
+
+ /* 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;
+ }
+ }
+
+ /* If no unused entry is found, we try to find the oldest entry and
+ * throw it away.
+ */
+
+ if (i == CONFIG_NET_ARPTAB_SIZE)
+ {
+ uint8 tmpage = 0;
+ int j = 0;
+ for (i = 0; i < CONFIG_NET_ARPTAB_SIZE; ++i)
+ {
+ tabptr = &g_arptable[i];
+ if (g_arptime - tabptr->at_time > tmpage)
+ {
+ tmpage = g_arptime - tabptr->at_time;
+ j = i;
+ }
+ }
+ i = j;
+ tabptr = &g_arptable[i];
+ }
+
+ /* Now, i 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;
+}
+
+/****************************************************************************
+ * Name: uip_arp_find
+ *
+ * Description:
+ * Find the ARP entry corresponding to this IP address.
+ *
+ * Input parameters:
+ * ipaddr - Refers to an IP addressin network order
+ *
+ * Assumptions
+ * Interrupts are disabled; Returned value will become unstable when
+ * interrupts are re-enabled or if any other uIP APIs are called.
+ *
+ ****************************************************************************/
+
+struct arp_entry *uip_arp_find(in_addr_t ipaddr)
+{
+ struct arp_entry *tabptr;
+ int i;
+
+ for (i = 0; i < CONFIG_NET_ARPTAB_SIZE; ++i)
+ {
+ tabptr = &g_arptable[i];
+ if (uip_ipaddr_cmp(ipaddr, tabptr->at_ipaddr))
+ {
+ return tabptr;
+ }
+ }
+ return NULL;
+}
+
+#endif /* CONFIG_NET */
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