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