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
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
|
/*
* 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;
int NetArpWaitTxPacketSize;
ulong NetArpWaitTimerStart;
int NetArpWaitTry;
uchar *NetArpTxPacket; /* THE ARP transmit packet */
uchar NetArpPacketBuf[PKTSIZE_ALIGN + PKTALIGN];
void ArpInit(void)
{
/* XXX problem with bss workaround */
NetArpWaitPacketMAC = NULL;
NetArpWaitPacketIP = 0;
NetArpWaitReplyIP = 0;
NetArpWaitTxPacketSize = 0;
NetArpTxPacket = &NetArpPacketBuf[0] + (PKTALIGN - 1);
NetArpTxPacket -= (ulong)NetArpTxPacket % PKTALIGN;
}
void arp_raw_request(IPaddr_t sourceIP, const uchar *targetEther,
IPaddr_t targetIP)
{
uchar *pkt;
struct arp_hdr *arp;
int eth_hdr_size;
debug("ARP broadcast %d\n", NetArpWaitTry);
pkt = NetArpTxPacket;
eth_hdr_size = NetSetEther(pkt, NetBcastAddr, PROT_ARP);
pkt += eth_hdr_size;
arp = (struct arp_hdr *) pkt;
arp->ar_hrd = htons(ARP_ETHER);
arp->ar_pro = htons(PROT_IP);
arp->ar_hln = ARP_HLEN;
arp->ar_pln = ARP_PLEN;
arp->ar_op = htons(ARPOP_REQUEST);
memcpy(&arp->ar_sha, NetOurEther, ARP_HLEN); /* source ET addr */
NetWriteIP(&arp->ar_spa, sourceIP); /* source IP addr */
memcpy(&arp->ar_tha, targetEther, ARP_HLEN); /* target ET addr */
NetWriteIP(&arp->ar_tpa, targetIP); /* target IP addr */
NetSendPacket(NetArpTxPacket, eth_hdr_size + ARP_HDR_SIZE);
}
void ArpRequest(void)
{
if ((NetArpWaitPacketIP & NetOurSubnetMask) !=
(NetOurIP & NetOurSubnetMask)) {
if (NetOurGatewayIP == 0) {
puts("## Warning: gatewayip needed but not set\n");
NetArpWaitReplyIP = NetArpWaitPacketIP;
} else {
NetArpWaitReplyIP = NetOurGatewayIP;
}
} else {
NetArpWaitReplyIP = NetArpWaitPacketIP;
}
arp_raw_request(NetOurIP, NetEtherNullAddr, NetArpWaitReplyIP);
}
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)
{
struct arp_hdr *arp;
IPaddr_t reply_ip_addr;
uchar *pkt;
int eth_hdr_size;
/*
* 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 = (struct arp_hdr *)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 != ARP_HLEN)
return;
if (arp->ar_pln != ARP_PLEN)
return;
if (NetOurIP == 0)
return;
if (NetReadIP(&arp->ar_tpa) != 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;
eth_hdr_size = net_update_ether(et, et->et_src, PROT_ARP);
pkt += eth_hdr_size;
arp->ar_op = htons(ARPOP_REPLY);
memcpy(&arp->ar_tha, &arp->ar_sha, ARP_HLEN);
NetCopyIP(&arp->ar_tpa, &arp->ar_spa);
memcpy(&arp->ar_sha, NetOurEther, ARP_HLEN);
NetCopyIP(&arp->ar_spa, &NetOurIP);
#ifdef CONFIG_CMD_LINK_LOCAL
/*
* Work-around for brain-damaged Cisco equipment with
* arp-proxy enabled.
*
* If the requesting IP is not on our subnet, wait 5ms to
* reply to ARP request so that our reply will overwrite
* the arp-proxy's instead of the other way around.
*/
if ((NetReadIP(&arp->ar_tpa) & NetOurSubnetMask) !=
(NetReadIP(&arp->ar_spa) & NetOurSubnetMask))
udelay(5000);
#endif
NetSendPacket((uchar *)et, eth_hdr_size + ARP_HDR_SIZE);
return;
case ARPOP_REPLY: /* arp reply */
/* are we waiting for a reply */
if (!NetArpWaitPacketIP)
break;
#ifdef CONFIG_KEEP_SERVERADDR
if (NetServerIP == NetArpWaitPacketIP) {
char buf[20];
sprintf(buf, "%pM", arp->ar_sha);
setenv("serveraddr", buf);
}
#endif
reply_ip_addr = NetReadIP(&arp->ar_spa);
/* matched waiting packet's address */
if (reply_ip_addr == NetArpWaitReplyIP) {
debug("Got ARP REPLY, set eth addr (%pM)\n",
arp->ar_data);
/* save address for later use */
if (NetArpWaitPacketMAC != NULL)
memcpy(NetArpWaitPacketMAC,
&arp->ar_sha, ARP_HLEN);
net_get_arp_handler()((uchar *)arp, 0, reply_ip_addr,
0, len);
/* set the mac address in the waiting packet's header
and transmit it */
memcpy(((struct ethernet_hdr *)NetTxPacket)->et_dest,
&arp->ar_sha, ARP_HLEN);
NetSendPacket(NetTxPacket, 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;
}
}
|
