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nuttx/net/arp/arp_table.c

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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/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
/****************************************************************************
* 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];
static uint8_t g_arptime;
/****************************************************************************
* 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;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: arp_reset
*
* Description:
* Re-initialize the ARP table.
*
****************************************************************************/
void arp_reset(void)
{
int i;
for (i = 0; i < CONFIG_NET_ARPTAB_SIZE; ++i)
{
memset(&g_arptable[i].at_ipaddr, 0, sizeof(in_addr_t));
}
}
/****************************************************************************
* Name: 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 arp_timer(void)
{
FAR struct arp_entry_s *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 >= CONFIG_NET_ARP_MAXAGE)
{
tabptr->at_ipaddr = 0;
}
}
}
/****************************************************************************
* 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)
{
struct arp_entry_s *tabptr = NULL;
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 (net_ipv4addr_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 OK;
}
}
}
/* 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;
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))
{
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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