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- /****************************************************************************
- * net/arp/arp_table.c
- * Implementation of the ARP Address Resolution Protocol.
- *
- * Copyright (C) 2007-2009, 2011, 2014, 2018 Gregory Nutt. All rights
- * reserved.
- * Author: Gregory Nutt <gnutt@nuttx.org>
- *
- * 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/ioctl.h>
- #include <stdint.h>
- #include <string.h>
- #include <debug.h>
- #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>
- #include <nuttx/net/arp.h>
- #include <nuttx/net/ip.h>
- #include <arp/arp.h>
- #include <netdev/netdev.h>
- #ifdef CONFIG_NET_ARP
- /****************************************************************************
- * Pre-processor Definitions
- ****************************************************************************/
- #define ARP_MAXAGE_TICK SEC2TICK(10 * CONFIG_NET_ARP_MAXAGE)
- /****************************************************************************
- * Private Types
- ****************************************************************************/
- struct arp_table_info_s
- {
- in_addr_t ai_ipaddr; /* IP address for lookup */
- FAR struct ether_addr *ai_ethaddr; /* Location to return the MAC address */
- };
- /****************************************************************************
- * Private Data
- ****************************************************************************/
- /* The table of known address mappings */
- static struct arp_entry_s g_arptable[CONFIG_NET_ARPTAB_SIZE];
- /****************************************************************************
- * Private Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: arp_match
- *
- * Description:
- * This is a callback that checks if the Ethernet network device has the
- * indicated IPv4 address assigned to it.
- *
- ****************************************************************************/
- static int arp_match(FAR struct net_driver_s *dev, FAR void *arg)
- {
- FAR struct arp_table_info_s *info = arg;
- /* Make sure that this is an Ethernet device (or an IEEE 802.11 device
- * which is also Ethernet)
- */
- if (dev->d_lltype != NET_LL_ETHERNET &&
- dev->d_lltype != NET_LL_IEEE80211)
- {
- return 0;
- }
- /* Check if the network device has been assigned the IP address of the
- * lookup.
- */
- if (!net_ipv4addr_cmp(dev->d_ipaddr, info->ai_ipaddr))
- {
- return 0;
- }
- /* Yes.. Return the matching Ethernet MAC address if the caller of
- * arp_find() provided a non-NULL location.
- */
- if (info->ai_ethaddr != NULL)
- {
- memcpy(info->ai_ethaddr, &dev->d_mac.ether, ETHER_ADDR_LEN);
- }
- /* Return success in any event */
- 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_update
- *
- * Description:
- * Add the IP/HW address mapping to the ARP table -OR- change the IP
- * address of an existing association.
- *
- * Input Parameters:
- * ipaddr - The IP address as an inaddr_t
- * ethaddr - Refers to a HW address uint8_t[IFHWADDRLEN]
- *
- * Returned Value:
- * Zero (OK) if the ARP table entry was successfully modified. A negated
- * errno value is returned on any error.
- *
- * Assumptions
- * The network is locked to assure exclusive access to the ARP table
- *
- ****************************************************************************/
- int arp_update(in_addr_t ipaddr, FAR uint8_t *ethaddr)
- {
- FAR struct arp_entry_s *tabptr = &g_arptable[0];
- 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)
- {
- /* Check if the source IP address of the incoming packet matches
- * the IP address in this ARP table entry.
- */
- if (g_arptable[i].at_ipaddr != 0 &&
- net_ipv4addr_cmp(ipaddr, g_arptable[i].at_ipaddr))
- {
- /* An old entry found, break. */
- tabptr = &g_arptable[i];
- break;
- }
- else
- {
- /* Record the oldest entry. */
- tabptr = arp_return_old_entry(tabptr, &g_arptable[i]);
- }
- }
- /* 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 = clock_systimer();
- return OK;
- }
- /****************************************************************************
- * Name: arp_hdr_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_t[2] in network order
- * ethaddr - Refers to a HW address uint8_t[IFHWADDRLEN]
- *
- * Returned Value:
- * Zero (OK) if the ARP table entry was successfully modified. A negated
- * errno value is returned on any error.
- *
- * Assumptions
- * The network is locked to assure exclusive access to the ARP table
- *
- ****************************************************************************/
- void arp_hdr_update(FAR uint16_t *pipaddr, FAR uint8_t *ethaddr)
- {
- in_addr_t ipaddr = net_ip4addr_conv32(pipaddr);
- /* Update the ARP table */
- (void)arp_update(ipaddr, ethaddr);
- }
- /****************************************************************************
- * Name: arp_lookup
- *
- * Description:
- * Find the ARP entry corresponding to this IP address in the ARP table.
- *
- * Input Parameters:
- * ipaddr - Refers to an IP address in network order
- *
- * Assumptions:
- * The network is locked to assure exclusive access to the ARP table.
- * The return value will become unstable when the network is unlocked.
- *
- ****************************************************************************/
- FAR struct arp_entry_s *arp_lookup(in_addr_t ipaddr)
- {
- FAR struct arp_entry_s *tabptr;
- int i;
- /* Check if the IPv4 address is already in the ARP table. */
- for (i = 0; i < CONFIG_NET_ARPTAB_SIZE; ++i)
- {
- tabptr = &g_arptable[i];
- if (net_ipv4addr_cmp(ipaddr, tabptr->at_ipaddr) &&
- clock_systimer() - tabptr->at_time <= ARP_MAXAGE_TICK)
- {
- return tabptr;
- }
- }
- /* Not found */
- return NULL;
- }
- /****************************************************************************
- * Name: arp_find
- *
- * Description:
- * Find the ARP entry corresponding to this IP address which may or may
- * not be in the ARP table (it may, instead, be a local network device).
- *
- * Input Parameters:
- * ipaddr - Refers to an IP address in network order
- * ethaddr - Location to return the corresponding Ethernet MAN address.
- * This address may be NULL. In that case, this function may be
- * used simply to determine if the Ethernet MAC address is
- * available.
- *
- * Assumptions
- * The network is locked to assure exclusive access to the ARP table.
- *
- ****************************************************************************/
- int arp_find(in_addr_t ipaddr, FAR struct ether_addr *ethaddr)
- {
- FAR struct arp_entry_s *tabptr;
- struct arp_table_info_s info;
- /* Check if the IPv4 address is already in the ARP table. */
- tabptr = arp_lookup(ipaddr);
- if (tabptr != NULL)
- {
- /* Yes.. return the Ethernet MAC address if the caller has provided a
- * non-NULL address in 'ethaddr'.
- */
- if (ethaddr != NULL)
- {
- memcpy(ethaddr, &tabptr->at_ethaddr, ETHER_ADDR_LEN);
- }
- /* Return success in any case meaning that a valid Ethernet MAC
- * address mapping is available for the IP address.
- */
- return OK;
- }
- /* No.. check if the IPv4 address is the address assigned to a local
- * Ethernet network device. If so, return a mapping of that IP address
- * to the Ethernet MAC address assigned to the network device.
- */
- info.ai_ipaddr = ipaddr;
- info.ai_ethaddr = ethaddr;
- if (netdev_foreach(arp_match, &info) != 0)
- {
- return OK;
- }
- /* Not found */
- return -ENOENT;
- }
- /****************************************************************************
- * Name: arp_delete
- *
- * Description:
- * Remove an IP association from the ARP table
- *
- * Input Parameters:
- * ipaddr - Refers to an IP address in network order
- *
- * Assumptions
- * The network is locked to assure exclusive access to the ARP table.
- *
- ****************************************************************************/
- void arp_delete(in_addr_t ipaddr)
- {
- FAR struct arp_entry_s *tabptr;
- /* Check if the IPv4 address is in the ARP table. */
- tabptr = arp_lookup(ipaddr);
- if (tabptr != NULL)
- {
- /* Yes.. Set the IP address to zero to "delete" it */
- tabptr->at_ipaddr = 0;
- }
- }
- #endif /* CONFIG_NET_ARP */
- #endif /* CONFIG_NET */
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