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