/* * 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 * SPDX-License-Identifier: GPL-2.0 */ #include #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 struct in_addr net_arp_wait_packet_ip; static struct in_addr net_arp_wait_reply_ip; /* MAC address of waiting packet's destination */ uchar *arp_wait_packet_ethaddr; int arp_wait_tx_packet_size; ulong arp_wait_timer_start; int arp_wait_try; static uchar *arp_tx_packet; /* THE ARP transmit packet */ static uchar arp_tx_packet_buf[PKTSIZE_ALIGN + PKTALIGN]; void arp_init(void) { /* XXX problem with bss workaround */ arp_wait_packet_ethaddr = NULL; net_arp_wait_packet_ip.s_addr = 0; net_arp_wait_reply_ip.s_addr = 0; arp_wait_tx_packet_size = 0; arp_tx_packet = &arp_tx_packet_buf[0] + (PKTALIGN - 1); arp_tx_packet -= (ulong)arp_tx_packet % PKTALIGN; } void arp_raw_request(struct in_addr source_ip, const uchar *target_ethaddr, struct in_addr target_ip) { uchar *pkt; struct arp_hdr *arp; int eth_hdr_size; debug_cond(DEBUG_DEV_PKT, "ARP broadcast %d\n", arp_wait_try); pkt = arp_tx_packet; eth_hdr_size = net_set_ether(pkt, net_bcast_ethaddr, 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, net_ethaddr, ARP_HLEN); /* source ET addr */ net_write_ip(&arp->ar_spa, source_ip); /* source IP addr */ memcpy(&arp->ar_tha, target_ethaddr, ARP_HLEN); /* target ET addr */ net_write_ip(&arp->ar_tpa, target_ip); /* target IP addr */ net_send_packet(arp_tx_packet, eth_hdr_size + ARP_HDR_SIZE); } void arp_request(void) { if ((net_arp_wait_packet_ip.s_addr & net_netmask.s_addr) != (net_ip.s_addr & net_netmask.s_addr)) { if (net_gateway.s_addr == 0) { puts("## Warning: gatewayip needed but not set\n"); net_arp_wait_reply_ip = net_arp_wait_packet_ip; } else { net_arp_wait_reply_ip = net_gateway; } } else { net_arp_wait_reply_ip = net_arp_wait_packet_ip; } arp_raw_request(net_ip, net_null_ethaddr, net_arp_wait_reply_ip); } int arp_timeout_check(void) { ulong t; if (!net_arp_wait_packet_ip.s_addr) return 0; t = get_timer(0); /* check for arp timeout */ if ((t - arp_wait_timer_start) > ARP_TIMEOUT) { arp_wait_try++; if (arp_wait_try >= ARP_TIMEOUT_COUNT) { puts("\nARP Retry count exceeded; starting again\n"); arp_wait_try = 0; net_set_state(NETLOOP_FAIL); } else { arp_wait_timer_start = t; arp_request(); } } return 1; } void arp_receive(struct ethernet_hdr *et, struct ip_udp_hdr *ip, int len) { struct arp_hdr *arp; struct in_addr 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 (net_ip.s_addr == 0) return; if (net_read_ip(&arp->ar_tpa).s_addr != net_ip.s_addr) 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); net_copy_ip(&arp->ar_tpa, &arp->ar_spa); memcpy(&arp->ar_sha, net_ethaddr, ARP_HLEN); net_copy_ip(&arp->ar_spa, &net_ip); #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 ((net_read_ip(&arp->ar_tpa).s_addr & net_netmask.s_addr) != (net_read_ip(&arp->ar_spa).s_addr & net_netmask.s_addr)) udelay(5000); #endif net_send_packet((uchar *)et, eth_hdr_size + ARP_HDR_SIZE); return; case ARPOP_REPLY: /* arp reply */ /* are we waiting for a reply */ if (!net_arp_wait_packet_ip.s_addr) break; #ifdef CONFIG_KEEP_SERVERADDR if (net_server_ip.s_addr == net_arp_wait_packet_ip.s_addr) { char buf[20]; sprintf(buf, "%pM", &arp->ar_sha); setenv("serveraddr", buf); } #endif reply_ip_addr = net_read_ip(&arp->ar_spa); /* matched waiting packet's address */ if (reply_ip_addr.s_addr == net_arp_wait_reply_ip.s_addr) { debug_cond(DEBUG_DEV_PKT, "Got ARP REPLY, set eth addr (%pM)\n", arp->ar_data); /* save address for later use */ if (arp_wait_packet_ethaddr != NULL) memcpy(arp_wait_packet_ethaddr, &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 *)net_tx_packet)->et_dest, &arp->ar_sha, ARP_HLEN); net_send_packet(net_tx_packet, arp_wait_tx_packet_size); /* no arp request pending now */ net_arp_wait_packet_ip.s_addr = 0; arp_wait_tx_packet_size = 0; arp_wait_packet_ethaddr = NULL; } return; default: debug("Unexpected ARP opcode 0x%x\n", ntohs(arp->ar_op)); return; } }