2 * Copied from Linux Monitor (LiMon) - Networking.
4 * Copyright 1994 - 2000 Neil Russell.
6 * Copyright 2000 Roland Borde
7 * Copyright 2000 Paolo Scaffardi
8 * Copyright 2000-2002 Wolfgang Denk, wd@denx.de
9 * SPDX-License-Identifier: GPL-2.0
16 #ifndef CONFIG_ARP_TIMEOUT
17 /* Milliseconds before trying ARP again */
18 # define ARP_TIMEOUT 5000UL
20 # define ARP_TIMEOUT CONFIG_ARP_TIMEOUT
24 #ifndef CONFIG_NET_RETRY_COUNT
25 # define ARP_TIMEOUT_COUNT 5 /* # of timeouts before giving up */
27 # define ARP_TIMEOUT_COUNT CONFIG_NET_RETRY_COUNT
30 struct in_addr net_arp_wait_packet_ip;
31 static struct in_addr net_arp_wait_reply_ip;
32 /* MAC address of waiting packet's destination */
33 uchar *arp_wait_packet_ethaddr;
34 int arp_wait_tx_packet_size;
35 ulong arp_wait_timer_start;
38 static uchar *arp_tx_packet; /* THE ARP transmit packet */
39 static uchar arp_tx_packet_buf[PKTSIZE_ALIGN + PKTALIGN];
43 /* XXX problem with bss workaround */
44 arp_wait_packet_ethaddr = NULL;
45 net_arp_wait_packet_ip.s_addr = 0;
46 net_arp_wait_reply_ip.s_addr = 0;
47 arp_wait_tx_packet_size = 0;
48 arp_tx_packet = &arp_tx_packet_buf[0] + (PKTALIGN - 1);
49 arp_tx_packet -= (ulong)arp_tx_packet % PKTALIGN;
52 void arp_raw_request(struct in_addr source_ip, const uchar *target_ethaddr,
53 struct in_addr target_ip)
59 debug_cond(DEBUG_DEV_PKT, "ARP broadcast %d\n", arp_wait_try);
63 eth_hdr_size = net_set_ether(pkt, net_bcast_ethaddr, PROT_ARP);
66 arp = (struct arp_hdr *)pkt;
68 arp->ar_hrd = htons(ARP_ETHER);
69 arp->ar_pro = htons(PROT_IP);
70 arp->ar_hln = ARP_HLEN;
71 arp->ar_pln = ARP_PLEN;
72 arp->ar_op = htons(ARPOP_REQUEST);
74 memcpy(&arp->ar_sha, net_ethaddr, ARP_HLEN); /* source ET addr */
75 net_write_ip(&arp->ar_spa, source_ip); /* source IP addr */
76 memcpy(&arp->ar_tha, target_ethaddr, ARP_HLEN); /* target ET addr */
77 net_write_ip(&arp->ar_tpa, target_ip); /* target IP addr */
79 net_send_packet(arp_tx_packet, eth_hdr_size + ARP_HDR_SIZE);
82 void arp_request(void)
84 if ((net_arp_wait_packet_ip.s_addr & net_netmask.s_addr) !=
85 (net_ip.s_addr & net_netmask.s_addr)) {
86 if (net_gateway.s_addr == 0) {
87 puts("## Warning: gatewayip needed but not set\n");
88 net_arp_wait_reply_ip = net_arp_wait_packet_ip;
90 net_arp_wait_reply_ip = net_gateway;
93 net_arp_wait_reply_ip = net_arp_wait_packet_ip;
96 arp_raw_request(net_ip, net_null_ethaddr, net_arp_wait_reply_ip);
99 int arp_timeout_check(void)
103 if (!net_arp_wait_packet_ip.s_addr)
108 /* check for arp timeout */
109 if ((t - arp_wait_timer_start) > ARP_TIMEOUT) {
112 if (arp_wait_try >= ARP_TIMEOUT_COUNT) {
113 puts("\nARP Retry count exceeded; starting again\n");
115 net_set_state(NETLOOP_FAIL);
117 arp_wait_timer_start = t;
124 void arp_receive(struct ethernet_hdr *et, struct ip_udp_hdr *ip, int len)
127 struct in_addr reply_ip_addr;
132 * We have to deal with two types of ARP packets:
133 * - REQUEST packets will be answered by sending our
134 * IP address - if we know it.
135 * - REPLY packates are expected only after we asked
136 * for the TFTP server's or the gateway's ethernet
137 * address; so if we receive such a packet, we set
138 * the server ethernet address
140 debug_cond(DEBUG_NET_PKT, "Got ARP\n");
142 arp = (struct arp_hdr *)ip;
143 if (len < ARP_HDR_SIZE) {
144 printf("bad length %d < %d\n", len, ARP_HDR_SIZE);
147 if (ntohs(arp->ar_hrd) != ARP_ETHER)
149 if (ntohs(arp->ar_pro) != PROT_IP)
151 if (arp->ar_hln != ARP_HLEN)
153 if (arp->ar_pln != ARP_PLEN)
156 if (net_ip.s_addr == 0)
159 if (net_read_ip(&arp->ar_tpa).s_addr != net_ip.s_addr)
162 switch (ntohs(arp->ar_op)) {
164 /* reply with our IP address */
165 debug_cond(DEBUG_DEV_PKT, "Got ARP REQUEST, return our IP\n");
167 eth_hdr_size = net_update_ether(et, et->et_src, PROT_ARP);
169 arp->ar_op = htons(ARPOP_REPLY);
170 memcpy(&arp->ar_tha, &arp->ar_sha, ARP_HLEN);
171 net_copy_ip(&arp->ar_tpa, &arp->ar_spa);
172 memcpy(&arp->ar_sha, net_ethaddr, ARP_HLEN);
173 net_copy_ip(&arp->ar_spa, &net_ip);
175 #ifdef CONFIG_CMD_LINK_LOCAL
177 * Work-around for brain-damaged Cisco equipment with
180 * If the requesting IP is not on our subnet, wait 5ms to
181 * reply to ARP request so that our reply will overwrite
182 * the arp-proxy's instead of the other way around.
184 if ((net_read_ip(&arp->ar_tpa).s_addr & net_netmask.s_addr) !=
185 (net_read_ip(&arp->ar_spa).s_addr & net_netmask.s_addr))
188 net_send_packet((uchar *)et, eth_hdr_size + ARP_HDR_SIZE);
191 case ARPOP_REPLY: /* arp reply */
192 /* are we waiting for a reply */
193 if (!net_arp_wait_packet_ip.s_addr)
196 #ifdef CONFIG_KEEP_SERVERADDR
197 if (net_server_ip.s_addr == net_arp_wait_packet_ip.s_addr) {
199 sprintf(buf, "%pM", &arp->ar_sha);
200 setenv("serveraddr", buf);
204 reply_ip_addr = net_read_ip(&arp->ar_spa);
206 /* matched waiting packet's address */
207 if (reply_ip_addr.s_addr == net_arp_wait_reply_ip.s_addr) {
208 debug_cond(DEBUG_DEV_PKT,
209 "Got ARP REPLY, set eth addr (%pM)\n",
212 /* save address for later use */
213 if (arp_wait_packet_ethaddr != NULL)
214 memcpy(arp_wait_packet_ethaddr,
215 &arp->ar_sha, ARP_HLEN);
217 net_get_arp_handler()((uchar *)arp, 0, reply_ip_addr,
220 /* set the mac address in the waiting packet's header
222 memcpy(((struct ethernet_hdr *)net_tx_packet)->et_dest,
223 &arp->ar_sha, ARP_HLEN);
224 net_send_packet(net_tx_packet, arp_wait_tx_packet_size);
226 /* no arp request pending now */
227 net_arp_wait_packet_ip.s_addr = 0;
228 arp_wait_tx_packet_size = 0;
229 arp_wait_packet_ethaddr = NULL;
233 debug("Unexpected ARP opcode 0x%x\n",