1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copied from Linux Monitor (LiMon) - Networking.
4 *
5 * Copyright 1994 - 2000 Neil Russell.
6 * (See License)
7 * Copyright 2000 Roland Borde
8 * Copyright 2000 Paolo Scaffardi
9 * Copyright 2000-2002 Wolfgang Denk, wd@denx.de
10 */
11
12 #include <common.h>
13 #include <env.h>
14 #include <log.h>
15 #include <net.h>
16 #include <linux/delay.h>
17
18 #include "arp.h"
19
20 #ifndef CONFIG_ARP_TIMEOUT
21 /* Milliseconds before trying ARP again */
22 # define ARP_TIMEOUT 5000UL
23 #else
24 # define ARP_TIMEOUT CONFIG_ARP_TIMEOUT
25 #endif
26
27
28 #ifndef CONFIG_NET_RETRY_COUNT
29 # define ARP_TIMEOUT_COUNT 5 /* # of timeouts before giving up */
30 #else
31 # define ARP_TIMEOUT_COUNT CONFIG_NET_RETRY_COUNT
32 #endif
33
34 struct in_addr net_arp_wait_packet_ip;
35 static struct in_addr net_arp_wait_reply_ip;
36 /* MAC address of waiting packet's destination */
37 uchar *arp_wait_packet_ethaddr;
38 int arp_wait_tx_packet_size;
39 ulong arp_wait_timer_start;
40 int arp_wait_try;
41 uchar *arp_tx_packet; /* THE ARP transmit packet */
42 static uchar arp_tx_packet_buf[PKTSIZE_ALIGN + PKTALIGN];
43
arp_init(void)44 void arp_init(void)
45 {
46 /* XXX problem with bss workaround */
47 arp_wait_packet_ethaddr = NULL;
48 net_arp_wait_packet_ip.s_addr = 0;
49 net_arp_wait_reply_ip.s_addr = 0;
50 arp_wait_tx_packet_size = 0;
51 arp_tx_packet = &arp_tx_packet_buf[0] + (PKTALIGN - 1);
52 arp_tx_packet -= (ulong)arp_tx_packet % PKTALIGN;
53 }
54
arp_raw_request(struct in_addr source_ip,const uchar * target_ethaddr,struct in_addr target_ip)55 void arp_raw_request(struct in_addr source_ip, const uchar *target_ethaddr,
56 struct in_addr target_ip)
57 {
58 uchar *pkt;
59 struct arp_hdr *arp;
60 int eth_hdr_size;
61
62 debug_cond(DEBUG_DEV_PKT, "ARP broadcast %d\n", arp_wait_try);
63
64 pkt = arp_tx_packet;
65
66 eth_hdr_size = net_set_ether(pkt, net_bcast_ethaddr, PROT_ARP);
67 pkt += eth_hdr_size;
68
69 arp = (struct arp_hdr *)pkt;
70
71 arp->ar_hrd = htons(ARP_ETHER);
72 arp->ar_pro = htons(PROT_IP);
73 arp->ar_hln = ARP_HLEN;
74 arp->ar_pln = ARP_PLEN;
75 arp->ar_op = htons(ARPOP_REQUEST);
76
77 memcpy(&arp->ar_sha, net_ethaddr, ARP_HLEN); /* source ET addr */
78 net_write_ip(&arp->ar_spa, source_ip); /* source IP addr */
79 memcpy(&arp->ar_tha, target_ethaddr, ARP_HLEN); /* target ET addr */
80 net_write_ip(&arp->ar_tpa, target_ip); /* target IP addr */
81
82 net_send_packet(arp_tx_packet, eth_hdr_size + ARP_HDR_SIZE);
83 }
84
arp_request(void)85 void arp_request(void)
86 {
87 if ((net_arp_wait_packet_ip.s_addr & net_netmask.s_addr) !=
88 (net_ip.s_addr & net_netmask.s_addr)) {
89 if (net_gateway.s_addr == 0) {
90 puts("## Warning: gatewayip needed but not set\n");
91 net_arp_wait_reply_ip = net_arp_wait_packet_ip;
92 } else {
93 net_arp_wait_reply_ip = net_gateway;
94 }
95 } else {
96 net_arp_wait_reply_ip = net_arp_wait_packet_ip;
97 }
98
99 arp_raw_request(net_ip, net_null_ethaddr, net_arp_wait_reply_ip);
100 }
101
arp_timeout_check(void)102 int arp_timeout_check(void)
103 {
104 ulong t;
105
106 if (!arp_is_waiting())
107 return 0;
108
109 t = get_timer(0);
110
111 /* check for arp timeout */
112 if ((t - arp_wait_timer_start) > ARP_TIMEOUT) {
113 arp_wait_try++;
114
115 if (arp_wait_try >= ARP_TIMEOUT_COUNT) {
116 puts("\nARP Retry count exceeded; starting again\n");
117 arp_wait_try = 0;
118 net_set_state(NETLOOP_FAIL);
119 } else {
120 arp_wait_timer_start = t;
121 arp_request();
122 }
123 }
124 return 1;
125 }
126
arp_receive(struct ethernet_hdr * et,struct ip_udp_hdr * ip,int len)127 void arp_receive(struct ethernet_hdr *et, struct ip_udp_hdr *ip, int len)
128 {
129 struct arp_hdr *arp;
130 struct in_addr reply_ip_addr;
131 int eth_hdr_size;
132 uchar *tx_packet;
133
134 /*
135 * We have to deal with two types of ARP packets:
136 * - REQUEST packets will be answered by sending our
137 * IP address - if we know it.
138 * - REPLY packates are expected only after we asked
139 * for the TFTP server's or the gateway's ethernet
140 * address; so if we receive such a packet, we set
141 * the server ethernet address
142 */
143 debug_cond(DEBUG_NET_PKT, "Got ARP\n");
144
145 arp = (struct arp_hdr *)ip;
146 if (len < ARP_HDR_SIZE) {
147 printf("bad length %d < %d\n", len, ARP_HDR_SIZE);
148 return;
149 }
150 if (ntohs(arp->ar_hrd) != ARP_ETHER)
151 return;
152 if (ntohs(arp->ar_pro) != PROT_IP)
153 return;
154 if (arp->ar_hln != ARP_HLEN)
155 return;
156 if (arp->ar_pln != ARP_PLEN)
157 return;
158
159 if (net_ip.s_addr == 0)
160 return;
161
162 if (net_read_ip(&arp->ar_tpa).s_addr != net_ip.s_addr)
163 return;
164
165 switch (ntohs(arp->ar_op)) {
166 case ARPOP_REQUEST:
167 /* reply with our IP address */
168 debug_cond(DEBUG_DEV_PKT, "Got ARP REQUEST, return our IP\n");
169 eth_hdr_size = net_update_ether(et, et->et_src, PROT_ARP);
170 arp->ar_op = htons(ARPOP_REPLY);
171 memcpy(&arp->ar_tha, &arp->ar_sha, ARP_HLEN);
172 net_copy_ip(&arp->ar_tpa, &arp->ar_spa);
173 memcpy(&arp->ar_sha, net_ethaddr, ARP_HLEN);
174 net_copy_ip(&arp->ar_spa, &net_ip);
175
176 #ifdef CONFIG_CMD_LINK_LOCAL
177 /*
178 * Work-around for brain-damaged Cisco equipment with
179 * arp-proxy enabled.
180 *
181 * If the requesting IP is not on our subnet, wait 5ms to
182 * reply to ARP request so that our reply will overwrite
183 * the arp-proxy's instead of the other way around.
184 */
185 if ((net_read_ip(&arp->ar_tpa).s_addr & net_netmask.s_addr) !=
186 (net_read_ip(&arp->ar_spa).s_addr & net_netmask.s_addr))
187 udelay(5000);
188 #endif
189 tx_packet = net_get_async_tx_pkt_buf();
190 memcpy(tx_packet, et, eth_hdr_size + ARP_HDR_SIZE);
191 net_send_packet(tx_packet, eth_hdr_size + ARP_HDR_SIZE);
192 return;
193
194 case ARPOP_REPLY: /* arp reply */
195 /* are we waiting for a reply? */
196 if (!arp_is_waiting())
197 break;
198
199 #ifdef CONFIG_KEEP_SERVERADDR
200 if (net_server_ip.s_addr == net_arp_wait_packet_ip.s_addr) {
201 char buf[20];
202 sprintf(buf, "%pM", &arp->ar_sha);
203 env_set("serveraddr", buf);
204 }
205 #endif
206
207 reply_ip_addr = net_read_ip(&arp->ar_spa);
208
209 /* matched waiting packet's address */
210 if (reply_ip_addr.s_addr == net_arp_wait_reply_ip.s_addr) {
211 debug_cond(DEBUG_DEV_PKT,
212 "Got ARP REPLY, set eth addr (%pM)\n",
213 arp->ar_data);
214
215 /* save address for later use */
216 if (arp_wait_packet_ethaddr != NULL)
217 memcpy(arp_wait_packet_ethaddr,
218 &arp->ar_sha, ARP_HLEN);
219
220 net_get_arp_handler()((uchar *)arp, 0, reply_ip_addr,
221 0, len);
222
223 /* set the mac address in the waiting packet's header
224 and transmit it */
225 memcpy(((struct ethernet_hdr *)net_tx_packet)->et_dest,
226 &arp->ar_sha, ARP_HLEN);
227 net_send_packet(net_tx_packet, arp_wait_tx_packet_size);
228
229 /* no arp request pending now */
230 net_arp_wait_packet_ip.s_addr = 0;
231 arp_wait_tx_packet_size = 0;
232 arp_wait_packet_ethaddr = NULL;
233 }
234 return;
235 default:
236 debug("Unexpected ARP opcode 0x%x\n",
237 ntohs(arp->ar_op));
238 return;
239 }
240 }
241
arp_is_waiting(void)242 bool arp_is_waiting(void)
243 {
244 return !!net_arp_wait_packet_ip.s_addr;
245 }
246