/**************************************************************************** * net/arp/arp_arpin.c * * Copyright (C) 2007-2011, 2014 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Based on uIP which also has a BSD style license: * * Author: Adam Dunkels * 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 #include #include #include #include #include #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)) { nllerr("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): nllinfo("ARP request for IP %04lx\n", (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_addr_octet, ETHER_ADDR_LEN); memcpy(eth->src, dev->d_mac.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): nllinfo("ARP reply for IP %04lx\n", (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 */