summaryrefslogtreecommitdiff
path: root/net/arp.c
blob: c3def633b649e98c51037e90f6d2df46f33af15c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
/*
 *	Copied from Linux Monitor (LiMon) - Networking.
 *
 *	Copyright 1994 - 2000 Neil Russell.
 *	(See License)
 *	Copyright 2000 Roland Borde
 *	Copyright 2000 Paolo Scaffardi
 *	Copyright 2000-2002 Wolfgang Denk, wd@denx.de
 */

#include <common.h>

#include "arp.h"

#ifndef	CONFIG_ARP_TIMEOUT
/* Milliseconds before trying ARP again */
# define ARP_TIMEOUT		5000UL
#else
# define ARP_TIMEOUT		CONFIG_ARP_TIMEOUT
#endif


#ifndef	CONFIG_NET_RETRY_COUNT
# define ARP_TIMEOUT_COUNT	5	/* # of timeouts before giving up  */
#else
# define ARP_TIMEOUT_COUNT	CONFIG_NET_RETRY_COUNT
#endif

IPaddr_t	NetArpWaitPacketIP;
IPaddr_t	NetArpWaitReplyIP;
/* MAC address of waiting packet's destination */
uchar	       *NetArpWaitPacketMAC;
/* THE transmit packet */
uchar	       *NetArpWaitTxPacket;
int		NetArpWaitTxPacketSize;
uchar		NetArpWaitPacketBuf[PKTSIZE_ALIGN + PKTALIGN];
ulong		NetArpWaitTimerStart;
int		NetArpWaitTry;

void ArpInit(void)
{
	/* XXX problem with bss workaround */
	NetArpWaitPacketMAC = NULL;
	NetArpWaitPacketIP = 0;
	NetArpWaitReplyIP = 0;
	NetArpWaitTxPacket = &NetArpWaitPacketBuf[0] + (PKTALIGN - 1);
	NetArpWaitTxPacket -= (ulong)NetArpWaitTxPacket % PKTALIGN;
	NetArpWaitTxPacketSize = 0;
}

void ArpRequest(void)
{
	uchar *pkt;
	ARP_t *arp;

	debug("ARP broadcast %d\n", NetArpWaitTry);

	pkt = NetTxPacket;

	pkt += NetSetEther(pkt, NetBcastAddr, PROT_ARP);

	arp = (ARP_t *) pkt;

	arp->ar_hrd = htons(ARP_ETHER);
	arp->ar_pro = htons(PROT_IP);
	arp->ar_hln = 6;
	arp->ar_pln = 4;
	arp->ar_op = htons(ARPOP_REQUEST);

	/* source ET addr */
	memcpy(&arp->ar_data[0], NetOurEther, 6);
	/* source IP addr */
	NetWriteIP((uchar *) &arp->ar_data[6], NetOurIP);
	/* dest ET addr = 0 */
	memset(&arp->ar_data[10], '\0', 6);
	if ((NetArpWaitPacketIP & NetOurSubnetMask) !=
	    (NetOurIP & NetOurSubnetMask)) {
		if (NetOurGatewayIP == 0) {
			puts("## Warning: gatewayip needed but not set\n");
			NetArpWaitReplyIP = NetArpWaitPacketIP;
		} else {
			NetArpWaitReplyIP = NetOurGatewayIP;
		}
	} else {
		NetArpWaitReplyIP = NetArpWaitPacketIP;
	}

	NetWriteIP((uchar *) &arp->ar_data[16], NetArpWaitReplyIP);
	(void) eth_send(NetTxPacket, (pkt - NetTxPacket) + ARP_HDR_SIZE);
}

void ArpTimeoutCheck(void)
{
	ulong t;

	if (!NetArpWaitPacketIP)
		return;

	t = get_timer(0);

	/* check for arp timeout */
	if ((t - NetArpWaitTimerStart) > ARP_TIMEOUT) {
		NetArpWaitTry++;

		if (NetArpWaitTry >= ARP_TIMEOUT_COUNT) {
			puts("\nARP Retry count exceeded; starting again\n");
			NetArpWaitTry = 0;
			NetStartAgain();
		} else {
			NetArpWaitTimerStart = t;
			ArpRequest();
		}
	}
}

void ArpReceive(struct ethernet_hdr *et, struct ip_udp_hdr *ip, int len)
{
	ARP_t *arp;
	IPaddr_t tmp;
	uchar *pkt;

	/*
	 * We have to deal with two types of ARP packets:
	 * - REQUEST packets will be answered by sending  our
	 *   IP address - if we know it.
	 * - REPLY packates are expected only after we asked
	 *   for the TFTP server's or the gateway's ethernet
	 *   address; so if we receive such a packet, we set
	 *   the server ethernet address
	 */
	debug("Got ARP\n");

	arp = (ARP_t *)ip;
	if (len < ARP_HDR_SIZE) {
		printf("bad length %d < %d\n", len, ARP_HDR_SIZE);
		return;
	}
	if (ntohs(arp->ar_hrd) != ARP_ETHER)
		return;
	if (ntohs(arp->ar_pro) != PROT_IP)
		return;
	if (arp->ar_hln != 6)
		return;
	if (arp->ar_pln != 4)
		return;

	if (NetOurIP == 0)
		return;

	if (NetReadIP(&arp->ar_data[16]) != NetOurIP)
		return;

	switch (ntohs(arp->ar_op)) {
	case ARPOP_REQUEST:
		/* reply with our IP address */
		debug("Got ARP REQUEST, return our IP\n");
		pkt = (uchar *)et;
		pkt += NetSetEther(pkt, et->et_src, PROT_ARP);
		arp->ar_op = htons(ARPOP_REPLY);
		memcpy(&arp->ar_data[10], &arp->ar_data[0], 6);
		NetCopyIP(&arp->ar_data[16], &arp->ar_data[6]);
		memcpy(&arp->ar_data[0], NetOurEther, 6);
		NetCopyIP(&arp->ar_data[6], &NetOurIP);
		(void) eth_send((uchar *)et,
				(pkt - (uchar *)et) + ARP_HDR_SIZE);
		return;

	case ARPOP_REPLY:		/* arp reply */
		/* are we waiting for a reply */
		if (!NetArpWaitPacketIP || !NetArpWaitPacketMAC)
			break;

#ifdef CONFIG_KEEP_SERVERADDR
		if (NetServerIP == NetArpWaitPacketIP) {
			char buf[20];
			sprintf(buf, "%pM", arp->ar_data);
			setenv("serveraddr", buf);
		}
#endif

		tmp = NetReadIP(&arp->ar_data[6]);

		/* matched waiting packet's address */
		if (tmp == NetArpWaitReplyIP) {
			debug("Got ARP REPLY, set eth addr (%pM)\n",
				arp->ar_data);

			/* save address for later use */
			memcpy(NetArpWaitPacketMAC,
			       &arp->ar_data[0], 6);

#ifdef CONFIG_NETCONSOLE
			NetGetHandler()(0, 0, 0, 0, 0);
#endif
			/* modify header, and transmit it */
			memcpy(((struct ethernet_hdr *)NetArpWaitTxPacket)->
				et_dest, NetArpWaitPacketMAC, 6);
			(void) eth_send(NetArpWaitTxPacket,
					NetArpWaitTxPacketSize);

			/* no arp request pending now */
			NetArpWaitPacketIP = 0;
			NetArpWaitTxPacketSize = 0;
			NetArpWaitPacketMAC = NULL;

		}
		return;
	default:
		debug("Unexpected ARP opcode 0x%x\n",
		      ntohs(arp->ar_op));
		return;
	}
}