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- /****************************************************************************
- * net/arp/arp_arpin.c
- *
- * Copyright (C) 2007-2011, 2014 Gregory Nutt. All rights reserved.
- * Author: Gregory Nutt <gnutt@nuttx.org>
- *
- * Based 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>
- #include <string.h>
- #include <debug.h>
- #include <netinet/in.h>
- #include <nuttx/net/netdev.h>
- #include <nuttx/net/arp.h>
- #include "arp/arp.h"
- #ifdef CONFIG_NET_ARP
- /****************************************************************************
- * Pre-processor Definitions
- ****************************************************************************/
- #define ETHBUF ((struct eth_hdr_s *)&dev->d_buf[0])
- #define ARPBUF ((struct arp_hdr_s *)&dev->d_buf[ETH_HDRLEN])
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: arp_arpin
- *
- * Description:
- * This function should be called by the Ethernet device driver when an
- * ARP packet has been received. The function will act differently
- * depending on the ARP packet type: if it is a reply for a request
- * that we previously sent out, the ARP cache will be filled in with
- * the values from the ARP reply. If the incoming ARP packet is an ARP
- * request for our IP address, an ARP reply packet is created and put
- * into the d_buf buffer.
- *
- * On entry, this function expects that an ARP packet with a prepended
- * Ethernet header is present in the d_buf buffer and that the length of
- * the packet is set in the d_len field.
- *
- * When the function returns, the value of the field d_len indicates
- * whether the device driver should send out the ARP reply packet or not.
- * If d_len is zero, no packet should be sent; If d_len is non-zero, it
- * contains the length of the outbound packet that is present in the
- * d_buf buffer.
- *
- ****************************************************************************/
- void arp_arpin(FAR struct net_driver_s *dev)
- {
- FAR struct arp_hdr_s *arp = ARPBUF;
- in_addr_t ipaddr;
- if (dev->d_len < (sizeof(struct arp_hdr_s) + ETH_HDRLEN))
- {
- nerr("ERROR: Packet Too small\n");
- dev->d_len = 0;
- return;
- }
- dev->d_len = 0;
- ipaddr = net_ip4addr_conv32(arp->ah_dipaddr);
- switch (arp->ah_opcode)
- {
- case HTONS(ARP_REQUEST):
- ninfo("ARP request for IP %04lx\n", (unsigned long)ipaddr);
- /* ARP request. If it asked for our address, we send out a reply. */
- if (net_ipv4addr_cmp(ipaddr, dev->d_ipaddr))
- {
- FAR struct eth_hdr_s *eth = ETHBUF;
- /* First, we register the one who made the request in our ARP
- * table, since it is likely that we will do more communication
- * with this host in the future.
- */
- arp_hdr_update(arp->ah_sipaddr, arp->ah_shwaddr);
- arp->ah_opcode = HTONS(ARP_REPLY);
- memcpy(arp->ah_dhwaddr, arp->ah_shwaddr, ETHER_ADDR_LEN);
- memcpy(arp->ah_shwaddr, dev->d_mac.ether.ether_addr_octet, ETHER_ADDR_LEN);
- memcpy(eth->src, dev->d_mac.ether.ether_addr_octet, ETHER_ADDR_LEN);
- memcpy(eth->dest, arp->ah_dhwaddr, ETHER_ADDR_LEN);
- arp->ah_dipaddr[0] = arp->ah_sipaddr[0];
- arp->ah_dipaddr[1] = arp->ah_sipaddr[1];
- net_ipv4addr_hdrcopy(arp->ah_sipaddr, &dev->d_ipaddr);
- arp_dump(arp);
- eth->type = HTONS(ETHTYPE_ARP);
- dev->d_len = sizeof(struct arp_hdr_s) + ETH_HDRLEN;
- }
- break;
- case HTONS(ARP_REPLY):
- ninfo("ARP reply for IP %04lx\n", (unsigned long)ipaddr);
- /* ARP reply. We insert or update the ARP table if it was meant
- * for us.
- */
- if (net_ipv4addr_cmp(ipaddr, dev->d_ipaddr))
- {
- /* Yes... Insert the address mapping in the ARP table */
- arp_hdr_update(arp->ah_sipaddr, arp->ah_shwaddr);
- /* Then notify any logic waiting for the ARP result */
- arp_notify(net_ip4addr_conv32(arp->ah_sipaddr));
- }
- break;
- }
- }
- #endif /* CONFIG_NET_ARP */
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