/* * Copied from Linux Monitor (LiMon) - Networking. * * Copyright 1994 - 2000 Neil Russell. * (See License) * Copyright 2000 Roland Borde * Copyright 2000 Paolo Scaffardi * Copyright 2000-2002 Wolfgang Denk, wd@denx.de */ #include <common.h> #include "arp.h" #ifndef CONFIG_ARP_TIMEOUT /* Milliseconds before trying ARP again */ # define ARP_TIMEOUT 5000UL #else # define ARP_TIMEOUT CONFIG_ARP_TIMEOUT #endif #ifndef CONFIG_NET_RETRY_COUNT # define ARP_TIMEOUT_COUNT 5 /* # of timeouts before giving up */ #else # define ARP_TIMEOUT_COUNT CONFIG_NET_RETRY_COUNT #endif IPaddr_t NetArpWaitPacketIP; static IPaddr_t NetArpWaitReplyIP; /* MAC address of waiting packet's destination */ uchar *NetArpWaitPacketMAC; int NetArpWaitTxPacketSize; ulong NetArpWaitTimerStart; int NetArpWaitTry; static uchar *NetArpTxPacket; /* THE ARP transmit packet */ static uchar NetArpPacketBuf[PKTSIZE_ALIGN + PKTALIGN]; void ArpInit(void) { /* XXX problem with bss workaround */ NetArpWaitPacketMAC = NULL; NetArpWaitPacketIP = 0; NetArpWaitReplyIP = 0; NetArpWaitTxPacketSize = 0; NetArpTxPacket = &NetArpPacketBuf[0] + (PKTALIGN - 1); NetArpTxPacket -= (ulong)NetArpTxPacket % PKTALIGN; } void arp_raw_request(IPaddr_t sourceIP, const uchar *targetEther, IPaddr_t targetIP) { uchar *pkt; struct arp_hdr *arp; int eth_hdr_size; debug_cond(DEBUG_DEV_PKT, "ARP broadcast %d\n", NetArpWaitTry); pkt = NetArpTxPacket; eth_hdr_size = NetSetEther(pkt, NetBcastAddr, PROT_ARP); pkt += eth_hdr_size; arp = (struct arp_hdr *) pkt; arp->ar_hrd = htons(ARP_ETHER); arp->ar_pro = htons(PROT_IP); arp->ar_hln = ARP_HLEN; arp->ar_pln = ARP_PLEN; arp->ar_op = htons(ARPOP_REQUEST); memcpy(&arp->ar_sha, NetOurEther, ARP_HLEN); /* source ET addr */ NetWriteIP(&arp->ar_spa, sourceIP); /* source IP addr */ memcpy(&arp->ar_tha, targetEther, ARP_HLEN); /* target ET addr */ NetWriteIP(&arp->ar_tpa, targetIP); /* target IP addr */ NetSendPacket(NetArpTxPacket, eth_hdr_size + ARP_HDR_SIZE); } void ArpRequest(void) { if ((NetArpWaitPacketIP & NetOurSubnetMask) != (NetOurIP & NetOurSubnetMask)) { if (NetOurGatewayIP == 0) { puts("## Warning: gatewayip needed but not set\n"); NetArpWaitReplyIP = NetArpWaitPacketIP; } else { NetArpWaitReplyIP = NetOurGatewayIP; } } else { NetArpWaitReplyIP = NetArpWaitPacketIP; } arp_raw_request(NetOurIP, NetEtherNullAddr, NetArpWaitReplyIP); } void ArpTimeoutCheck(void) { ulong t; if (!NetArpWaitPacketIP) return; t = get_timer(0); /* check for arp timeout */ if ((t - NetArpWaitTimerStart) > ARP_TIMEOUT) { NetArpWaitTry++; if (NetArpWaitTry >= ARP_TIMEOUT_COUNT) { puts("\nARP Retry count exceeded; starting again\n"); NetArpWaitTry = 0; NetStartAgain(); } else { NetArpWaitTimerStart = t; ArpRequest(); } } } void ArpReceive(struct ethernet_hdr *et, struct ip_udp_hdr *ip, int len) { struct arp_hdr *arp; IPaddr_t reply_ip_addr; uchar *pkt; int eth_hdr_size; /* * We have to deal with two types of ARP packets: * - REQUEST packets will be answered by sending our * IP address - if we know it. * - REPLY packates are expected only after we asked * for the TFTP server's or the gateway's ethernet * address; so if we receive such a packet, we set * the server ethernet address */ debug_cond(DEBUG_NET_PKT, "Got ARP\n"); arp = (struct arp_hdr *)ip; if (len < ARP_HDR_SIZE) { printf("bad length %d < %d\n", len, ARP_HDR_SIZE); return; } if (ntohs(arp->ar_hrd) != ARP_ETHER) return; if (ntohs(arp->ar_pro) != PROT_IP) return; if (arp->ar_hln != ARP_HLEN) return; if (arp->ar_pln != ARP_PLEN) return; if (NetOurIP == 0) return; if (NetReadIP(&arp->ar_tpa) != NetOurIP) return; switch (ntohs(arp->ar_op)) { case ARPOP_REQUEST: /* reply with our IP address */ debug_cond(DEBUG_DEV_PKT, "Got ARP REQUEST, return our IP\n"); pkt = (uchar *)et; eth_hdr_size = net_update_ether(et, et->et_src, PROT_ARP); pkt += eth_hdr_size; arp->ar_op = htons(ARPOP_REPLY); memcpy(&arp->ar_tha, &arp->ar_sha, ARP_HLEN); NetCopyIP(&arp->ar_tpa, &arp->ar_spa); memcpy(&arp->ar_sha, NetOurEther, ARP_HLEN); NetCopyIP(&arp->ar_spa, &NetOurIP); #ifdef CONFIG_CMD_LINK_LOCAL /* * Work-around for brain-damaged Cisco equipment with * arp-proxy enabled. * * If the requesting IP is not on our subnet, wait 5ms to * reply to ARP request so that our reply will overwrite * the arp-proxy's instead of the other way around. */ if ((NetReadIP(&arp->ar_tpa) & NetOurSubnetMask) != (NetReadIP(&arp->ar_spa) & NetOurSubnetMask)) udelay(5000); #endif NetSendPacket((uchar *)et, eth_hdr_size + ARP_HDR_SIZE); return; case ARPOP_REPLY: /* arp reply */ /* are we waiting for a reply */ if (!NetArpWaitPacketIP) break; #ifdef CONFIG_KEEP_SERVERADDR if (NetServerIP == NetArpWaitPacketIP) { char buf[20]; sprintf(buf, "%pM", &arp->ar_sha); setenv("serveraddr", buf); } #endif reply_ip_addr = NetReadIP(&arp->ar_spa); /* matched waiting packet's address */ if (reply_ip_addr == NetArpWaitReplyIP) { debug_cond(DEBUG_DEV_PKT, "Got ARP REPLY, set eth addr (%pM)\n", arp->ar_data); /* save address for later use */ if (NetArpWaitPacketMAC != NULL) memcpy(NetArpWaitPacketMAC, &arp->ar_sha, ARP_HLEN); net_get_arp_handler()((uchar *)arp, 0, reply_ip_addr, 0, len); /* set the mac address in the waiting packet's header and transmit it */ memcpy(((struct ethernet_hdr *)NetTxPacket)->et_dest, &arp->ar_sha, ARP_HLEN); NetSendPacket(NetTxPacket, NetArpWaitTxPacketSize); /* no arp request pending now */ NetArpWaitPacketIP = 0; NetArpWaitTxPacketSize = 0; NetArpWaitPacketMAC = NULL; } return; default: debug("Unexpected ARP opcode 0x%x\n", ntohs(arp->ar_op)); return; } }