286 lines
8.3 KiB
C
286 lines
8.3 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 Gregory Nutt. All rights 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/net/netconfig.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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#ifdef CONFIG_NET_ARP
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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 g_arptable[CONFIG_NET_ARPTAB_SIZE];
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static uint8_t g_arptime;
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: arp_reset
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*
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* Description:
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* Re-initialize the ARP table.
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*
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****************************************************************************/
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void arp_reset(void)
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{
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int i;
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for (i = 0; i < CONFIG_NET_ARPTAB_SIZE; ++i)
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{
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memset(&g_arptable[i].at_ipaddr, 0, sizeof(in_addr_t));
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}
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}
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/****************************************************************************
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* Name: arp_timer
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*
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* Description:
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* This function performs periodic timer processing in the ARP module
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* and should be called at regular intervals. The recommended interval
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* is 10 seconds between the calls. It is responsible for flushing old
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* entries in the ARP table.
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*
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****************************************************************************/
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void arp_timer(void)
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{
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FAR struct arp_entry *tabptr;
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int i;
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++g_arptime;
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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 (tabptr->at_ipaddr != 0 &&
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g_arptime - tabptr->at_time >= CONFIG_NET_ARP_MAXAGE)
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{
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tabptr->at_ipaddr = 0;
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}
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}
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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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struct arp_entry *tabptr = NULL;
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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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tabptr = &g_arptable[i];
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/* Only check those entries that are actually in use. */
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if (tabptr->at_ipaddr != 0)
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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 (net_ipv4addr_cmp(ipaddr, tabptr->at_ipaddr))
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{
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/* An old entry found, update this and return. */
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memcpy(tabptr->at_ethaddr.ether_addr_octet, ethaddr, ETHER_ADDR_LEN);
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tabptr->at_time = g_arptime;
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return OK;
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}
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}
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}
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/* If we get here, no existing ARP table entry was found, so we create one. */
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/* First, we try to find an unused entry 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 (tabptr->at_ipaddr == 0)
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{
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break;
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}
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}
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/* If no unused entry is found, we try to find the oldest entry and
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* throw it away.
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*/
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if (i == CONFIG_NET_ARPTAB_SIZE)
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{
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uint8_t tmpage = 0;
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int j = 0;
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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 (g_arptime - tabptr->at_time > tmpage)
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{
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tmpage = g_arptime - tabptr->at_time;
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j = i;
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}
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}
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i = j;
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tabptr = &g_arptable[i];
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}
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/* Now, i 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 = g_arptime;
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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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(void)arp_update(ipaddr, ethaddr);
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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.
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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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* Interrupts are disabled; Returned value will become unstable when
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* interrupts are re-enabled or if any other network APIs are called.
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*
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****************************************************************************/
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FAR struct arp_entry *arp_find(in_addr_t ipaddr)
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{
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FAR struct arp_entry *tabptr;
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int i;
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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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{
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return tabptr;
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}
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}
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return NULL;
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}
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#endif /* CONFIG_NET_ARP */
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#endif /* CONFIG_NET */
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