aboutsummaryrefslogtreecommitdiffstats
path: root/print-bfd.c
blob: 0e766ca3a4a8520f9c2e617650e333776c351a2f (plain) (blame)
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
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
/*
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that: (1) source code
 * distributions retain the above copyright notice and this paragraph
 * in its entirety, and (2) distributions including binary code include
 * the above copyright notice and this paragraph in its entirety in
 * the documentation or other materials provided with the distribution.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
 * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
 * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE.
 *
 * Original code by Hannes Gredler (hannes@gredler.at)
 */

/* \summary: Bidirectional Forwarding Detection (BFD) printer */

/*
 * specification: draft-ietf-bfd-base-01 for version 0,
 * RFC 5880 for version 1, and RFC 5881
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <netdissect-stdinc.h>

#include "netdissect.h"
#include "extract.h"

#include "udp.h"

/*
 * Control packet, BFDv0, draft-ietf-bfd-base-01
 *
 *     0                   1                   2                   3
 *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |Vers |  Diag   |H|D|P|F|C|A|Rsv|  Detect Mult  |    Length     |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                       My Discriminator                        |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                      Your Discriminator                       |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                    Desired Min TX Interval                    |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                   Required Min RX Interval                    |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                 Required Min Echo RX Interval                 |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */

/*
 *  Control packet, BFDv1, RFC 5880
 *
 *     0                   1                   2                   3
 *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |Vers |  Diag   |Sta|P|F|C|A|D|M|  Detect Mult  |    Length     |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                       My Discriminator                        |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                      Your Discriminator                       |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                    Desired Min TX Interval                    |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                   Required Min RX Interval                    |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                 Required Min Echo RX Interval                 |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */

struct bfd_header_t {
    uint8_t version_diag;
    uint8_t flags;
    uint8_t detect_time_multiplier;
    uint8_t length;
    uint8_t my_discriminator[4];
    uint8_t your_discriminator[4];
    uint8_t desired_min_tx_interval[4];
    uint8_t required_min_rx_interval[4];
    uint8_t required_min_echo_interval[4];
};

/*
 *    An optional Authentication Header may be present
 *
 *     0                   1                   2                   3
 *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |   Auth Type   |   Auth Len    |    Authentication Data...     |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */

struct bfd_auth_header_t {
    uint8_t auth_type;
    uint8_t auth_len;
    uint8_t auth_data;
    uint8_t dummy; /* minimun 4 bytes */
};

enum auth_type {
    AUTH_PASSWORD = 1,
    AUTH_MD5      = 2,
    AUTH_MET_MD5  = 3,
    AUTH_SHA1     = 4,
    AUTH_MET_SHA1 = 5
};

static const struct tok bfd_v1_authentication_values[] = {
    { AUTH_PASSWORD, "Simple Password" },
    { AUTH_MD5,      "Keyed MD5" },
    { AUTH_MET_MD5,  "Meticulous Keyed MD5" },
    { AUTH_SHA1,     "Keyed SHA1" },
    { AUTH_MET_SHA1, "Meticulous Keyed SHA1" },
    { 0, NULL }
};

enum auth_length {
    AUTH_PASSWORD_FIELD_MIN_LEN = 4,  /* header + password min: 3 + 1 */
    AUTH_PASSWORD_FIELD_MAX_LEN = 19, /* header + password max: 3 + 16 */
    AUTH_MD5_FIELD_LEN  = 24,
    AUTH_MD5_HASH_LEN   = 16,
    AUTH_SHA1_FIELD_LEN = 28,
    AUTH_SHA1_HASH_LEN  = 20
};

#define BFD_EXTRACT_VERSION(x) (((x)&0xe0)>>5)
#define BFD_EXTRACT_DIAG(x)     ((x)&0x1f)

static const struct tok bfd_diag_values[] = {
    { 0, "No Diagnostic" },
    { 1, "Control Detection Time Expired" },
    { 2, "Echo Function Failed" },
    { 3, "Neighbor Signaled Session Down" },
    { 4, "Forwarding Plane Reset" },
    { 5, "Path Down" },
    { 6, "Concatenated Path Down" },
    { 7, "Administratively Down" },
    { 8, "Reverse Concatenated Path Down" },
    { 0, NULL }
};

#define BFD_FLAG_AUTH 0x04

static const struct tok bfd_v0_flag_values[] = {
    { 0x80, "I Hear You" },
    { 0x40, "Demand" },
    { 0x20, "Poll" },
    { 0x10, "Final" },
    { 0x08, "Control Plane Independent" },
    { BFD_FLAG_AUTH, "Authentication Present" },
    { 0x02, "Reserved" },
    { 0x01, "Reserved" },
    { 0, NULL }
};

static const struct tok bfd_v1_flag_values[] = {
    { 0x20, "Poll" },
    { 0x10, "Final" },
    { 0x08, "Control Plane Independent" },
    { BFD_FLAG_AUTH, "Authentication Present" },
    { 0x02, "Demand" },
    { 0x01, "Multipoint" },
    { 0, NULL }
};

static const struct tok bfd_v1_state_values[] = {
    { 0, "AdminDown" },
    { 1, "Down" },
    { 2, "Init" },
    { 3, "Up" },
    { 0, NULL }
};

static int
auth_print(netdissect_options *ndo, register const u_char *pptr)
{
        const struct bfd_auth_header_t *bfd_auth_header;
        int i;

        pptr += sizeof (const struct bfd_header_t);
        bfd_auth_header = (const struct bfd_auth_header_t *)pptr;
        ND_TCHECK(*bfd_auth_header);
        ND_PRINT((ndo, "\n\tAuthentication: %s (%u), length: %u",
                 tok2str(bfd_v1_authentication_values,"Unknown",bfd_auth_header->auth_type),
                 bfd_auth_header->auth_type,
                 bfd_auth_header->auth_len));
                pptr += 2;
                ND_PRINT((ndo, "\n\t  Auth Key ID: %d", *pptr));

        switch(bfd_auth_header->auth_type) {
            case AUTH_PASSWORD:
/*
 *    Simple Password Authentication Section Format
 *
 *     0                   1                   2                   3
 *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |   Auth Type   |   Auth Len    |  Auth Key ID  |  Password...  |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                              ...                              |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
                if (bfd_auth_header->auth_len < AUTH_PASSWORD_FIELD_MIN_LEN ||
                    bfd_auth_header->auth_len > AUTH_PASSWORD_FIELD_MAX_LEN) {
                    ND_PRINT((ndo, "[invalid length %d]",
                             bfd_auth_header->auth_len));
                    break;
                }
                pptr++;
                ND_PRINT((ndo, ", Password: "));
                /* the length is equal to the password length plus three */
                if (fn_printn(ndo, pptr, bfd_auth_header->auth_len - 3,
                              ndo->ndo_snapend))
                    goto trunc;
                break;
            case AUTH_MD5:
            case AUTH_MET_MD5:
/*
 *    Keyed MD5 and Meticulous Keyed MD5 Authentication Section Format
 *
 *     0                   1                   2                   3
 *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |   Auth Type   |   Auth Len    |  Auth Key ID  |   Reserved    |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                        Sequence Number                        |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                      Auth Key/Digest...                       |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                              ...                              |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
                if (bfd_auth_header->auth_len != AUTH_MD5_FIELD_LEN) {
                    ND_PRINT((ndo, "[invalid length %d]",
                             bfd_auth_header->auth_len));
                    break;
                }
                pptr += 2;
                ND_TCHECK2(*pptr, 4);
                ND_PRINT((ndo, ", Sequence Number: 0x%08x", EXTRACT_32BITS(pptr)));
                pptr += 4;
                ND_TCHECK2(*pptr, AUTH_MD5_HASH_LEN);
                ND_PRINT((ndo, "\n\t  Digest: "));
                for(i = 0; i < AUTH_MD5_HASH_LEN; i++)
                    ND_PRINT((ndo, "%02x", pptr[i]));
                break;
            case AUTH_SHA1:
            case AUTH_MET_SHA1:
/*
 *    Keyed SHA1 and Meticulous Keyed SHA1 Authentication Section Format
 *
 *     0                   1                   2                   3
 *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |   Auth Type   |   Auth Len    |  Auth Key ID  |   Reserved    |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                        Sequence Number                        |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                       Auth Key/Hash...                        |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                              ...                              |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
                if (bfd_auth_header->auth_len != AUTH_SHA1_FIELD_LEN) {
                    ND_PRINT((ndo, "[invalid length %d]",
                             bfd_auth_header->auth_len));
                    break;
                }
                pptr += 2;
                ND_TCHECK2(*pptr, 4);
                ND_PRINT((ndo, ", Sequence Number: 0x%08x", EXTRACT_32BITS(pptr)));
                pptr += 4;
                ND_TCHECK2(*pptr, AUTH_SHA1_HASH_LEN);
                ND_PRINT((ndo, "\n\t  Hash: "));
                for(i = 0; i < AUTH_SHA1_HASH_LEN; i++)
                    ND_PRINT((ndo, "%02x", pptr[i]));
                break;
        }
        return 0;

trunc:
        return 1;
}

void
bfd_print(netdissect_options *ndo, register const u_char *pptr,
          register u_int len, register u_int port)
{
        if (port == BFD_CONTROL_PORT) {
            /*
             * Control packet.
             */
            const struct bfd_header_t *bfd_header;
            uint8_t version_diag;
            uint8_t version = 0;
            uint8_t flags;

            bfd_header = (const struct bfd_header_t *)pptr;
            ND_TCHECK(*bfd_header);
            version_diag = bfd_header->version_diag;
            version = BFD_EXTRACT_VERSION(version_diag);
            flags = bfd_header->flags;

            switch (version) {

                /* BFDv0 */
            case 0:
                if (ndo->ndo_vflag < 1)
                {
                    ND_PRINT((ndo, "BFDv0, Control, Flags: [%s], length: %u",
                           bittok2str(bfd_v0_flag_values, "none", flags),
                           len));
                    return;
                }

                ND_PRINT((ndo, "BFDv0, length: %u\n\tControl, Flags: [%s], Diagnostic: %s (0x%02x)",
                       len,
                       bittok2str(bfd_v0_flag_values, "none", flags),
                       tok2str(bfd_diag_values,"unknown",BFD_EXTRACT_DIAG(version_diag)),
                       BFD_EXTRACT_DIAG(version_diag)));

                ND_PRINT((ndo, "\n\tDetection Timer Multiplier: %u (%u ms Detection time), BFD Length: %u",
                       bfd_header->detect_time_multiplier,
                       bfd_header->detect_time_multiplier * EXTRACT_32BITS(bfd_header->desired_min_tx_interval)/1000,
                       bfd_header->length));


                ND_PRINT((ndo, "\n\tMy Discriminator: 0x%08x", EXTRACT_32BITS(bfd_header->my_discriminator)));
                ND_PRINT((ndo, ", Your Discriminator: 0x%08x", EXTRACT_32BITS(bfd_header->your_discriminator)));
                ND_PRINT((ndo, "\n\t  Desired min Tx Interval:    %4u ms", EXTRACT_32BITS(bfd_header->desired_min_tx_interval)/1000));
                ND_PRINT((ndo, "\n\t  Required min Rx Interval:   %4u ms", EXTRACT_32BITS(bfd_header->required_min_rx_interval)/1000));
                ND_PRINT((ndo, "\n\t  Required min Echo Interval: %4u ms", EXTRACT_32BITS(bfd_header->required_min_echo_interval)/1000));

                if (flags & BFD_FLAG_AUTH) {
                    if (auth_print(ndo, pptr))
                        goto trunc;
                }
                break;

                /* BFDv1 */
            case 1:
                if (ndo->ndo_vflag < 1)
                {
                    ND_PRINT((ndo, "BFDv1, Control, State %s, Flags: [%s], length: %u",
                           tok2str(bfd_v1_state_values, "unknown (%u)", (flags & 0xc0) >> 6),
                           bittok2str(bfd_v1_flag_values, "none", flags & 0x3f),
                           len));
                    return;
                }

                ND_PRINT((ndo, "BFDv1, length: %u\n\tControl, State %s, Flags: [%s], Diagnostic: %s (0x%02x)",
                       len,
                       tok2str(bfd_v1_state_values, "unknown (%u)", (flags & 0xc0) >> 6),
                       bittok2str(bfd_v1_flag_values, "none", flags & 0x3f),
                       tok2str(bfd_diag_values,"unknown",BFD_EXTRACT_DIAG(version_diag)),
                       BFD_EXTRACT_DIAG(version_diag)));

                ND_PRINT((ndo, "\n\tDetection Timer Multiplier: %u (%u ms Detection time), BFD Length: %u",
                       bfd_header->detect_time_multiplier,
                       bfd_header->detect_time_multiplier * EXTRACT_32BITS(bfd_header->desired_min_tx_interval)/1000,
                       bfd_header->length));


                ND_PRINT((ndo, "\n\tMy Discriminator: 0x%08x", EXTRACT_32BITS(bfd_header->my_discriminator)));
                ND_PRINT((ndo, ", Your Discriminator: 0x%08x", EXTRACT_32BITS(bfd_header->your_discriminator)));
                ND_PRINT((ndo, "\n\t  Desired min Tx Interval:    %4u ms", EXTRACT_32BITS(bfd_header->desired_min_tx_interval)/1000));
                ND_PRINT((ndo, "\n\t  Required min Rx Interval:   %4u ms", EXTRACT_32BITS(bfd_header->required_min_rx_interval)/1000));
                ND_PRINT((ndo, "\n\t  Required min Echo Interval: %4u ms", EXTRACT_32BITS(bfd_header->required_min_echo_interval)/1000));

                if (flags & BFD_FLAG_AUTH) {
                    if (auth_print(ndo, pptr))
                        goto trunc;
                }
                break;

            default:
                ND_PRINT((ndo, "BFDv%u, Control, length: %u",
                       version,
                       len));
                if (ndo->ndo_vflag >= 1) {
                    if(!print_unknown_data(ndo, pptr,"\n\t",len))
                        return;
                }
                break;
            }
        } else if (port == BFD_ECHO_PORT) {
            /*
             * Echo packet.
             */
            ND_PRINT((ndo, "BFD, Echo, length: %u",
                   len));
            if (ndo->ndo_vflag >= 1) {
                if(!print_unknown_data(ndo, pptr,"\n\t",len))
                    return;
            }
        } else {
            /*
             * Unknown packet type.
             */
            ND_PRINT((ndo, "BFD, unknown (%u), length: %u",
                   port,
                   len));
            if (ndo->ndo_vflag >= 1) {
                    if(!print_unknown_data(ndo, pptr,"\n\t",len))
                            return;
            }
        }
        return;

trunc:
        ND_PRINT((ndo, "[|BFD]"));
}
/*
 * Local Variables:
 * c-style: whitesmith
 * c-basic-offset: 8
 * End:
 */