448 lines
13 KiB
C
448 lines
13 KiB
C
/****************************************************************************
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* net/arp/arp_table.c
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* Implementation of the ARP Address Resolution Protocol.
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*
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* Copyright (C) 2007-2009, 2011, 2014, 2018 Gregory Nutt. All rights
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* reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Based originally on uIP which also has a BSD style license:
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*
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* Author: Adam Dunkels <adam@dunkels.com>
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* Copyright (c) 2001-2003, Adam Dunkels.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
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* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
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* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#ifdef CONFIG_NET
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#include <sys/ioctl.h>
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#include <stdint.h>
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#include <string.h>
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#include <debug.h>
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#include <netinet/in.h>
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#include <net/ethernet.h>
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#include <nuttx/clock.h>
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#include <nuttx/net/netconfig.h>
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#include <nuttx/net/net.h>
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#include <nuttx/net/netdev.h>
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#include <nuttx/net/arp.h>
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#include <nuttx/net/ip.h>
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#include <arp/arp.h>
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#include <netdev/netdev.h>
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#ifdef CONFIG_NET_ARP
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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#define ARP_MAXAGE_TICK SEC2TICK(10 * CONFIG_NET_ARP_MAXAGE)
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/****************************************************************************
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* Private Types
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****************************************************************************/
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struct arp_table_info_s
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{
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in_addr_t ai_ipaddr; /* IP address for lookup */
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FAR struct ether_addr *ai_ethaddr; /* Location to return the MAC address */
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};
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/****************************************************************************
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* Private Data
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****************************************************************************/
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/* The table of known address mappings */
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static struct arp_entry_s g_arptable[CONFIG_NET_ARPTAB_SIZE];
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: arp_match
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*
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* Description:
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* This is a callback that checks if the Ethernet network device has the
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* indicated IPv4 address assigned to it.
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*
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****************************************************************************/
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static int arp_match(FAR struct net_driver_s *dev, FAR void *arg)
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{
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FAR struct arp_table_info_s *info = arg;
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/* Make sure that this is an Ethernet device (or an IEEE 802.11 device
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* which is also Ethernet)
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*/
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if (dev->d_lltype != NET_LL_ETHERNET &&
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dev->d_lltype != NET_LL_IEEE80211)
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{
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return 0;
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}
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/* Check if the network device has been assigned the IP address of the
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* lookup.
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*/
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if (!net_ipv4addr_cmp(dev->d_ipaddr, info->ai_ipaddr))
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{
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return 0;
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}
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/* Yes.. Return the matching Ethernet MAC address if the caller of
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* arp_find() provided a non-NULL location.
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*/
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if (info->ai_ethaddr != NULL)
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{
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memcpy(info->ai_ethaddr, &dev->d_mac.ether, ETHER_ADDR_LEN);
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}
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/* Return success in any event */
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return 1;
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}
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/****************************************************************************
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* Name: arp_return_old_entry
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*
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* Description:
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* Compare and return the old ARP table entry.
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*
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****************************************************************************/
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static FAR struct arp_entry_s *
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arp_return_old_entry(FAR struct arp_entry_s *e1, FAR struct arp_entry_s *e2)
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{
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if (e1->at_ipaddr == 0)
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{
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return e1;
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}
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else if (e2->at_ipaddr == 0)
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{
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return e2;
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}
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else if ((int)(e1->at_time - e2->at_time) <= 0)
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{
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return e1;
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}
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else
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{
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return e2;
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}
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: arp_update
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*
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* Description:
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* Add the IP/HW address mapping to the ARP table -OR- change the IP
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* address of an existing association.
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*
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* Input Parameters:
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* ipaddr - The IP address as an inaddr_t
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* ethaddr - Refers to a HW address uint8_t[IFHWADDRLEN]
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*
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* Returned Value:
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* Zero (OK) if the ARP table entry was successfully modified. A negated
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* errno value is returned on any error.
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*
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* Assumptions
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* The network is locked to assure exclusive access to the ARP table
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*
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****************************************************************************/
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int arp_update(in_addr_t ipaddr, FAR uint8_t *ethaddr)
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{
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FAR struct arp_entry_s *tabptr = &g_arptable[0];
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int i;
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/* Walk through the ARP mapping table and try to find an entry to
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* update. If none is found, the IP -> MAC address mapping is
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* inserted in the ARP table.
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*/
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for (i = 0; i < CONFIG_NET_ARPTAB_SIZE; ++i)
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{
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/* Check if the source IP address of the incoming packet matches
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* the IP address in this ARP table entry.
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*/
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if (g_arptable[i].at_ipaddr != 0 &&
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net_ipv4addr_cmp(ipaddr, g_arptable[i].at_ipaddr))
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{
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/* An old entry found, break. */
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tabptr = &g_arptable[i];
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break;
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}
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else
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{
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/* Record the oldest entry. */
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tabptr = arp_return_old_entry(tabptr, &g_arptable[i]);
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}
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}
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/* Now, tabptr is the ARP table entry which we will fill with the new
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* information.
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*/
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tabptr->at_ipaddr = ipaddr;
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memcpy(tabptr->at_ethaddr.ether_addr_octet, ethaddr, ETHER_ADDR_LEN);
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tabptr->at_time = clock_systime_ticks();
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return OK;
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}
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/****************************************************************************
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* Name: arp_hdr_update
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*
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* Description:
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* Add the IP/HW address mapping to the ARP table -OR- change the IP
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* address of an existing association.
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*
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* Input Parameters:
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* pipaddr - Refers to an IP address uint16_t[2] in network order
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* ethaddr - Refers to a HW address uint8_t[IFHWADDRLEN]
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*
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* Returned Value:
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* Zero (OK) if the ARP table entry was successfully modified. A negated
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* errno value is returned on any error.
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*
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* Assumptions
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* The network is locked to assure exclusive access to the ARP table
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*
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****************************************************************************/
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void arp_hdr_update(FAR uint16_t *pipaddr, FAR uint8_t *ethaddr)
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{
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in_addr_t ipaddr = net_ip4addr_conv32(pipaddr);
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/* Update the ARP table */
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arp_update(ipaddr, ethaddr);
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}
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/****************************************************************************
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* Name: arp_lookup
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*
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* Description:
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* Find the ARP entry corresponding to this IP address in the ARP table.
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*
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* Input Parameters:
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* ipaddr - Refers to an IP address in network order
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*
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* Assumptions:
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* The network is locked to assure exclusive access to the ARP table.
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* The return value will become unstable when the network is unlocked.
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*
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****************************************************************************/
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FAR struct arp_entry_s *arp_lookup(in_addr_t ipaddr)
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{
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FAR struct arp_entry_s *tabptr;
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int i;
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/* Check if the IPv4 address is already in the ARP table. */
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for (i = 0; i < CONFIG_NET_ARPTAB_SIZE; ++i)
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{
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tabptr = &g_arptable[i];
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if (net_ipv4addr_cmp(ipaddr, tabptr->at_ipaddr) &&
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clock_systime_ticks() - tabptr->at_time <= ARP_MAXAGE_TICK)
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{
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return tabptr;
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}
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}
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/* Not found */
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return NULL;
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}
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/****************************************************************************
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* Name: arp_find
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*
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* Description:
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* Find the ARP entry corresponding to this IP address which may or may
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* not be in the ARP table (it may, instead, be a local network device).
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*
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* Input Parameters:
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* ipaddr - Refers to an IP address in network order
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* ethaddr - Location to return the corresponding Ethernet MAN address.
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* This address may be NULL. In that case, this function may be
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* used simply to determine if the Ethernet MAC address is
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* available.
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*
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* Assumptions
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* The network is locked to assure exclusive access to the ARP table.
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*
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****************************************************************************/
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int arp_find(in_addr_t ipaddr, FAR struct ether_addr *ethaddr)
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{
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FAR struct arp_entry_s *tabptr;
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struct arp_table_info_s info;
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/* Check if the IPv4 address is already in the ARP table. */
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tabptr = arp_lookup(ipaddr);
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if (tabptr != NULL)
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{
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/* Yes.. return the Ethernet MAC address if the caller has provided a
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* non-NULL address in 'ethaddr'.
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*/
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if (ethaddr != NULL)
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{
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memcpy(ethaddr, &tabptr->at_ethaddr, ETHER_ADDR_LEN);
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}
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/* Return success in any case meaning that a valid Ethernet MAC
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* address mapping is available for the IP address.
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*/
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return OK;
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}
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/* No.. check if the IPv4 address is the address assigned to a local
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* Ethernet network device. If so, return a mapping of that IP address
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* to the Ethernet MAC address assigned to the network device.
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*/
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info.ai_ipaddr = ipaddr;
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info.ai_ethaddr = ethaddr;
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if (netdev_foreach(arp_match, &info) != 0)
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{
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return OK;
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}
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/* Not found */
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return -ENOENT;
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}
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/****************************************************************************
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* Name: arp_delete
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*
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* Description:
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* Remove an IP association from the ARP table
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*
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* Input Parameters:
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* ipaddr - Refers to an IP address in network order
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*
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* Assumptions
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* The network is locked to assure exclusive access to the ARP table.
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*
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****************************************************************************/
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void arp_delete(in_addr_t ipaddr)
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{
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FAR struct arp_entry_s *tabptr;
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/* Check if the IPv4 address is in the ARP table. */
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tabptr = arp_lookup(ipaddr);
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if (tabptr != NULL)
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{
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/* Yes.. Set the IP address to zero to "delete" it */
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tabptr->at_ipaddr = 0;
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}
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}
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/****************************************************************************
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* Name: arp_snapshot
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*
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* Description:
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* Take a snapshot of the current state of the ARP table.
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*
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* Input Parameters:
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* snapshot - Location to return the ARP table copy
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* nentries - The size of the user provided 'dest' in entries, each of
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* size sizeof(struct arp_entry_s)
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*
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* Returned Value:
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* On success, the number of entries actually copied is returned. Unused
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* entries are not returned.
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*
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* Assumptions
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* The network is locked to assure exclusive access to the ARP table
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*
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****************************************************************************/
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#ifdef CONFIG_NETLINK_ROUTE
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unsigned int arp_snapshot(FAR struct arp_entry_s *snapshot,
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unsigned int nentries)
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{
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FAR struct arp_entry_s *tabptr;
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clock_t now;
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unsigned int ncopied;
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int i;
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/* Copy all non-empty, non-expired entries in the ARP table. */
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for (i = 0, now = clock_systime_ticks(), ncopied = 0;
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nentries > ncopied && i < CONFIG_NET_ARPTAB_SIZE;
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i++)
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{
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tabptr = &g_arptable[i];
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if (tabptr->at_ipaddr != 0 &&
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now - tabptr->at_time <= ARP_MAXAGE_TICK)
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{
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memcpy(&snapshot[ncopied], tabptr, sizeof(struct arp_entry_s));
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ncopied++;
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}
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}
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/* Return the number of entries copied into the user buffer */
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return ncopied;
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}
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#endif
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#endif /* CONFIG_NET_ARP */
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#endif /* CONFIG_NET */
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