xref: /openbmc/u-boot/net/arp.c (revision 9dbaebcf)
1 /*
2  *	Copied from Linux Monitor (LiMon) - Networking.
3  *
4  *	Copyright 1994 - 2000 Neil Russell.
5  *	(See License)
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
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 
38 static uchar   *arp_tx_packet;	/* THE ARP transmit packet */
39 static uchar	arp_tx_packet_buf[PKTSIZE_ALIGN + PKTALIGN];
40 
41 void arp_init(void)
42 {
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;
50 }
51 
52 void arp_raw_request(struct in_addr source_ip, const uchar *target_ethaddr,
53 	struct in_addr target_ip)
54 {
55 	uchar *pkt;
56 	struct arp_hdr *arp;
57 	int eth_hdr_size;
58 
59 	debug_cond(DEBUG_DEV_PKT, "ARP broadcast %d\n", arp_wait_try);
60 
61 	pkt = arp_tx_packet;
62 
63 	eth_hdr_size = net_set_ether(pkt, net_bcast_ethaddr, PROT_ARP);
64 	pkt += eth_hdr_size;
65 
66 	arp = (struct arp_hdr *)pkt;
67 
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);
73 
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 */
78 
79 	net_send_packet(arp_tx_packet, eth_hdr_size + ARP_HDR_SIZE);
80 }
81 
82 void arp_request(void)
83 {
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;
89 		} else {
90 			net_arp_wait_reply_ip = net_gateway;
91 		}
92 	} else {
93 		net_arp_wait_reply_ip = net_arp_wait_packet_ip;
94 	}
95 
96 	arp_raw_request(net_ip, net_null_ethaddr, net_arp_wait_reply_ip);
97 }
98 
99 int arp_timeout_check(void)
100 {
101 	ulong t;
102 
103 	if (!net_arp_wait_packet_ip.s_addr)
104 		return 0;
105 
106 	t = get_timer(0);
107 
108 	/* check for arp timeout */
109 	if ((t - arp_wait_timer_start) > ARP_TIMEOUT) {
110 		arp_wait_try++;
111 
112 		if (arp_wait_try >= ARP_TIMEOUT_COUNT) {
113 			puts("\nARP Retry count exceeded; starting again\n");
114 			arp_wait_try = 0;
115 			net_set_state(NETLOOP_FAIL);
116 		} else {
117 			arp_wait_timer_start = t;
118 			arp_request();
119 		}
120 	}
121 	return 1;
122 }
123 
124 void arp_receive(struct ethernet_hdr *et, struct ip_udp_hdr *ip, int len)
125 {
126 	struct arp_hdr *arp;
127 	struct in_addr reply_ip_addr;
128 	int eth_hdr_size;
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 		net_send_packet((uchar *)et, eth_hdr_size + ARP_HDR_SIZE);
186 		return;
187 
188 	case ARPOP_REPLY:		/* arp reply */
189 		/* are we waiting for a reply */
190 		if (!net_arp_wait_packet_ip.s_addr)
191 			break;
192 
193 #ifdef CONFIG_KEEP_SERVERADDR
194 		if (net_server_ip.s_addr == net_arp_wait_packet_ip.s_addr) {
195 			char buf[20];
196 			sprintf(buf, "%pM", &arp->ar_sha);
197 			env_set("serveraddr", buf);
198 		}
199 #endif
200 
201 		reply_ip_addr = net_read_ip(&arp->ar_spa);
202 
203 		/* matched waiting packet's address */
204 		if (reply_ip_addr.s_addr == net_arp_wait_reply_ip.s_addr) {
205 			debug_cond(DEBUG_DEV_PKT,
206 				   "Got ARP REPLY, set eth addr (%pM)\n",
207 				   arp->ar_data);
208 
209 			/* save address for later use */
210 			if (arp_wait_packet_ethaddr != NULL)
211 				memcpy(arp_wait_packet_ethaddr,
212 				       &arp->ar_sha, ARP_HLEN);
213 
214 			net_get_arp_handler()((uchar *)arp, 0, reply_ip_addr,
215 					      0, len);
216 
217 			/* set the mac address in the waiting packet's header
218 			   and transmit it */
219 			memcpy(((struct ethernet_hdr *)net_tx_packet)->et_dest,
220 			       &arp->ar_sha, ARP_HLEN);
221 			net_send_packet(net_tx_packet, arp_wait_tx_packet_size);
222 
223 			/* no arp request pending now */
224 			net_arp_wait_packet_ip.s_addr = 0;
225 			arp_wait_tx_packet_size = 0;
226 			arp_wait_packet_ethaddr = NULL;
227 		}
228 		return;
229 	default:
230 		debug("Unexpected ARP opcode 0x%x\n",
231 		      ntohs(arp->ar_op));
232 		return;
233 	}
234 }
235