summaryrefslogtreecommitdiffstats
path: root/net/cdp.c
blob: f9ccf5323183d98cf10435192d17502c7a8cd069 (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
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
/*
 *	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
 *	SPDX-License-Identifier:	GPL-2.0
 */

#include <common.h>
#include <net.h>
#if defined(CONFIG_CDP_VERSION)
#include <timestamp.h>
#endif

#include "cdp.h"

/* Ethernet bcast address */
const u8 net_cdp_ethaddr[6] = { 0x01, 0x00, 0x0c, 0xcc, 0xcc, 0xcc };

#define CDP_DEVICE_ID_TLV		0x0001
#define CDP_ADDRESS_TLV			0x0002
#define CDP_PORT_ID_TLV			0x0003
#define CDP_CAPABILITIES_TLV		0x0004
#define CDP_VERSION_TLV			0x0005
#define CDP_PLATFORM_TLV		0x0006
#define CDP_NATIVE_VLAN_TLV		0x000a
#define CDP_APPLIANCE_VLAN_TLV		0x000e
#define CDP_TRIGGER_TLV			0x000f
#define CDP_POWER_CONSUMPTION_TLV	0x0010
#define CDP_SYSNAME_TLV			0x0014
#define CDP_SYSOBJECT_TLV		0x0015
#define CDP_MANAGEMENT_ADDRESS_TLV	0x0016

#define CDP_TIMEOUT			250UL	/* one packet every 250ms */

static int cdp_seq;
static int cdp_ok;

ushort cdp_native_vlan;
ushort cdp_appliance_vlan;

static const uchar cdp_snap_hdr[8] = {
	0xAA, 0xAA, 0x03, 0x00, 0x00, 0x0C, 0x20, 0x00 };

static ushort cdp_compute_csum(const uchar *buff, ushort len)
{
	ushort csum;
	int     odd;
	ulong   result = 0;
	ushort  leftover;
	ushort *p;

	if (len > 0) {
		odd = 1 & (ulong)buff;
		if (odd) {
			result = *buff << 8;
			len--;
			buff++;
		}
		while (len > 1) {
			p = (ushort *)buff;
			result += *p++;
			buff = (uchar *)p;
			if (result & 0x80000000)
				result = (result & 0xFFFF) + (result >> 16);
			len -= 2;
		}
		if (len) {
			leftover = (signed short)(*(const signed char *)buff);
			/*
			 * CISCO SUCKS big time! (and blows too):
			 * CDP uses the IP checksum algorithm with a twist;
			 * for the last byte it *sign* extends and sums.
			 */
			result = (result & 0xffff0000) |
				 ((result + leftover) & 0x0000ffff);
		}
		while (result >> 16)
			result = (result & 0xFFFF) + (result >> 16);

		if (odd)
			result = ((result >> 8) & 0xff) |
				 ((result & 0xff) << 8);
	}

	/* add up 16-bit and 17-bit words for 17+c bits */
	result = (result & 0xffff) + (result >> 16);
	/* add up 16-bit and 2-bit for 16+c bit */
	result = (result & 0xffff) + (result >> 16);
	/* add up carry.. */
	result = (result & 0xffff) + (result >> 16);

	/* negate */
	csum = ~(ushort)result;

	/* run time endian detection */
	if (csum != htons(csum))	/* little endian */
		csum = htons(csum);

	return csum;
}

static int cdp_send_trigger(void)
{
	uchar *pkt;
	ushort *s;
	ushort *cp;
	struct ethernet_hdr *et;
	int len;
	ushort chksum;
#if	defined(CONFIG_CDP_DEVICE_ID) || defined(CONFIG_CDP_PORT_ID)   || \
	defined(CONFIG_CDP_VERSION)   || defined(CONFIG_CDP_PLATFORM)
	char buf[32];
#endif

	pkt = net_tx_packet;
	et = (struct ethernet_hdr *)pkt;

	/* NOTE: trigger sent not on any VLAN */

	/* form ethernet header */
	memcpy(et->et_dest, net_cdp_ethaddr, 6);
	memcpy(et->et_src, net_ethaddr, 6);

	pkt += ETHER_HDR_SIZE;

	/* SNAP header */
	memcpy((uchar *)pkt, cdp_snap_hdr, sizeof(cdp_snap_hdr));
	pkt += sizeof(cdp_snap_hdr);

	/* CDP header */
	*pkt++ = 0x02;				/* CDP version 2 */
	*pkt++ = 180;				/* TTL */
	s = (ushort *)pkt;
	cp = s;
	/* checksum (0 for later calculation) */
	*s++ = htons(0);

	/* CDP fields */
#ifdef CONFIG_CDP_DEVICE_ID
	*s++ = htons(CDP_DEVICE_ID_TLV);
	*s++ = htons(CONFIG_CDP_DEVICE_ID);
	sprintf(buf, CONFIG_CDP_DEVICE_ID_PREFIX "%pm", net_ethaddr);
	memcpy((uchar *)s, buf, 16);
	s += 16 / 2;
#endif

#ifdef CONFIG_CDP_PORT_ID
	*s++ = htons(CDP_PORT_ID_TLV);
	memset(buf, 0, sizeof(buf));
	sprintf(buf, CONFIG_CDP_PORT_ID, eth_get_dev_index());
	len = strlen(buf);
	if (len & 1)	/* make it even */
		len++;
	*s++ = htons(len + 4);
	memcpy((uchar *)s, buf, len);
	s += len / 2;
#endif

#ifdef CONFIG_CDP_CAPABILITIES
	*s++ = htons(CDP_CAPABILITIES_TLV);
	*s++ = htons(8);
	*(ulong *)s = htonl(CONFIG_CDP_CAPABILITIES);
	s += 2;
#endif

#ifdef CONFIG_CDP_VERSION
	*s++ = htons(CDP_VERSION_TLV);
	memset(buf, 0, sizeof(buf));
	strcpy(buf, CONFIG_CDP_VERSION);
	len = strlen(buf);
	if (len & 1)	/* make it even */
		len++;
	*s++ = htons(len + 4);
	memcpy((uchar *)s, buf, len);
	s += len / 2;
#endif

#ifdef CONFIG_CDP_PLATFORM
	*s++ = htons(CDP_PLATFORM_TLV);
	memset(buf, 0, sizeof(buf));
	strcpy(buf, CONFIG_CDP_PLATFORM);
	len = strlen(buf);
	if (len & 1)	/* make it even */
		len++;
	*s++ = htons(len + 4);
	memcpy((uchar *)s, buf, len);
	s += len / 2;
#endif

#ifdef CONFIG_CDP_TRIGGER
	*s++ = htons(CDP_TRIGGER_TLV);
	*s++ = htons(8);
	*(ulong *)s = htonl(CONFIG_CDP_TRIGGER);
	s += 2;
#endif

#ifdef CONFIG_CDP_POWER_CONSUMPTION
	*s++ = htons(CDP_POWER_CONSUMPTION_TLV);
	*s++ = htons(6);
	*s++ = htons(CONFIG_CDP_POWER_CONSUMPTION);
#endif

	/* length of ethernet packet */
	len = (uchar *)s - ((uchar *)net_tx_packet + ETHER_HDR_SIZE);
	et->et_protlen = htons(len);

	len = ETHER_HDR_SIZE + sizeof(cdp_snap_hdr);
	chksum = cdp_compute_csum((uchar *)net_tx_packet + len,
				  (uchar *)s - (net_tx_packet + len));
	if (chksum == 0)
		chksum = 0xFFFF;
	*cp = htons(chksum);

	net_send_packet(net_tx_packet, (uchar *)s - net_tx_packet);
	return 0;
}

static void cdp_timeout_handler(void)
{
	cdp_seq++;

	if (cdp_seq < 3) {
		net_set_timeout_handler(CDP_TIMEOUT, cdp_timeout_handler);
		cdp_send_trigger();
		return;
	}

	/* if not OK try again */
	if (!cdp_ok)
		net_start_again();
	else
		net_set_state(NETLOOP_SUCCESS);
}

void cdp_receive(const uchar *pkt, unsigned len)
{
	const uchar *t;
	const ushort *ss;
	ushort type, tlen;
	ushort vlan, nvlan;

	/* minimum size? */
	if (len < sizeof(cdp_snap_hdr) + 4)
		goto pkt_short;

	/* check for valid CDP SNAP header */
	if (memcmp(pkt, cdp_snap_hdr, sizeof(cdp_snap_hdr)) != 0)
		return;

	pkt += sizeof(cdp_snap_hdr);
	len -= sizeof(cdp_snap_hdr);

	/* Version of CDP protocol must be >= 2 and TTL != 0 */
	if (pkt[0] < 0x02 || pkt[1] == 0)
		return;

	/*
	 * if version is greater than 0x02 maybe we'll have a problem;
	 * output a warning
	 */
	if (pkt[0] != 0x02)
		printf("**WARNING: CDP packet received with a protocol version "
				"%d > 2\n", pkt[0] & 0xff);

	if (cdp_compute_csum(pkt, len) != 0)
		return;

	pkt += 4;
	len -= 4;

	vlan = htons(-1);
	nvlan = htons(-1);
	while (len > 0) {
		if (len < 4)
			goto pkt_short;

		ss = (const ushort *)pkt;
		type = ntohs(ss[0]);
		tlen = ntohs(ss[1]);
		if (tlen > len)
			goto pkt_short;

		pkt += tlen;
		len -= tlen;

		ss += 2;	/* point ss to the data of the TLV */
		tlen -= 4;

		switch (type) {
		case CDP_DEVICE_ID_TLV:
			break;
		case CDP_ADDRESS_TLV:
			break;
		case CDP_PORT_ID_TLV:
			break;
		case CDP_CAPABILITIES_TLV:
			break;
		case CDP_VERSION_TLV:
			break;
		case CDP_PLATFORM_TLV:
			break;
		case CDP_NATIVE_VLAN_TLV:
			nvlan = *ss;
			break;
		case CDP_APPLIANCE_VLAN_TLV:
			t = (const uchar *)ss;
			while (tlen > 0) {
				if (tlen < 3)
					goto pkt_short;

				ss = (const ushort *)(t + 1);

#ifdef CONFIG_CDP_APPLIANCE_VLAN_TYPE
				if (t[0] == CONFIG_CDP_APPLIANCE_VLAN_TYPE)
					vlan = *ss;
#else
				/* XXX will this work; dunno */
				vlan = ntohs(*ss);
#endif
				t += 3; tlen -= 3;
			}
			break;
		case CDP_TRIGGER_TLV:
			break;
		case CDP_POWER_CONSUMPTION_TLV:
			break;
		case CDP_SYSNAME_TLV:
			break;
		case CDP_SYSOBJECT_TLV:
			break;
		case CDP_MANAGEMENT_ADDRESS_TLV:
			break;
		}
	}

	cdp_appliance_vlan = vlan;
	cdp_native_vlan = nvlan;

	cdp_ok = 1;
	return;

pkt_short:
	printf("** CDP packet is too short\n");
	return;
}

void cdp_start(void)
{
	printf("Using %s device\n", eth_get_name());
	cdp_seq = 0;
	cdp_ok = 0;

	cdp_native_vlan = htons(-1);
	cdp_appliance_vlan = htons(-1);

	net_set_timeout_handler(CDP_TIMEOUT, cdp_timeout_handler);

	cdp_send_trigger();
}
OpenPOWER on IntegriCloud