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px4-firmware/nuttx/net/uip/uip_arptab.c

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/****************************************************************************
* net/uip/uip_arptab.c
* Implementation of the ARP Address Resolution Protocol.
*
* Copyright (C) 2007-2009, 2011 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/ioctl.h>
#include <stdint.h>
#include <string.h>
#include <debug.h>
#include <netinet/in.h>
#include <net/ethernet.h>
#include <nuttx/net/uip/uipopt.h>
#include <nuttx/net/uip/uip-arch.h>
#include <nuttx/net/uip/uip-arp.h>
#ifdef CONFIG_NET_ARP
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/* The table of known address mappings */
static struct arp_entry g_arptable[CONFIG_NET_ARPTAB_SIZE];
static uint8_t 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_t[2]
* ethaddr - Refers to a HW address uint8_t[IFHWADDRLEN]
*
* Assumptions
* Interrupts are disabled
*
****************************************************************************/
void uip_arp_update(uint16_t *pipaddr, uint8_t *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_t 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_ARP */
#endif /* CONFIG_NET */
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