print-stp.c revision 1.5 
1/*
2 * Copyright (c) 2000 Lennert Buytenhek
3 *
4 * This software may be distributed either under the terms of the
5 * BSD-style license that accompanies tcpdump or the GNU General
6 * Public License
7 *
8 * Format and print IEEE 802.1d spanning tree protocol packets.
9 * Contributed by Lennert Buytenhek <buytenh@gnu.org>
10 */
11
12#include <sys/cdefs.h>
13#ifndef lint
14__RCSID("$NetBSD: print-stp.c,v 1.5 2014/11/20 03:05:03 christos Exp $");
15#endif
16
17#define NETDISSECT_REWORKED
18#ifdef HAVE_CONFIG_H
19#include "config.h"
20#endif
21
22#include <tcpdump-stdinc.h>
23
24#include <stdio.h>
25
26#include "interface.h"
27#include "extract.h"
28
29#define	RSTP_EXTRACT_PORT_ROLE(x) (((x)&0x0C)>>2)
30/* STP timers are expressed in multiples of 1/256th second */
31#define STP_TIME_BASE 256
32#define STP_BPDU_MSTP_MIN_LEN 102
33
34struct stp_bpdu_ {
35    uint8_t protocol_id[2];
36    uint8_t protocol_version;
37    uint8_t bpdu_type;
38    uint8_t flags;
39    uint8_t root_id[8];
40    uint8_t root_path_cost[4];
41    uint8_t bridge_id[8];
42    uint8_t port_id[2];
43    uint8_t message_age[2];
44    uint8_t max_age[2];
45    uint8_t hello_time[2];
46    uint8_t forward_delay[2];
47    uint8_t v1_length;
48};
49
50#define STP_PROTO_REGULAR 0x00
51#define STP_PROTO_RAPID   0x02
52#define STP_PROTO_MSTP    0x03
53#define STP_PROTO_SPB     0x04
54
55static const struct tok stp_proto_values[] = {
56    { STP_PROTO_REGULAR, "802.1d" },
57    { STP_PROTO_RAPID, "802.1w" },
58    { STP_PROTO_MSTP, "802.1s" },
59    { STP_PROTO_SPB, "802.1aq" },
60    { 0, NULL}
61};
62
63#define STP_BPDU_TYPE_CONFIG      0x00
64#define STP_BPDU_TYPE_RSTP        0x02
65#define STP_BPDU_TYPE_TOPO_CHANGE 0x80
66
67static const struct tok stp_bpdu_flag_values[] = {
68    { 0x01, "Topology change" },
69    { 0x02, "Proposal" },
70    { 0x10, "Learn" },
71    { 0x20, "Forward" },
72    { 0x40, "Agreement" },
73    { 0x80, "Topology change ACK" },
74    { 0, NULL}
75};
76
77static const struct tok stp_bpdu_type_values[] = {
78    { STP_BPDU_TYPE_CONFIG, "Config" },
79    { STP_BPDU_TYPE_RSTP, "Rapid STP" },
80    { STP_BPDU_TYPE_TOPO_CHANGE, "Topology Change" },
81    { 0, NULL}
82};
83
84static const struct tok rstp_obj_port_role_values[] = {
85    { 0x00, "Unknown" },
86    { 0x01, "Alternate" },
87    { 0x02, "Root" },
88    { 0x03, "Designated" },
89    { 0, NULL}
90};
91
92static char *
93stp_print_bridge_id(const u_char *p)
94{
95    static char bridge_id_str[sizeof("pppp.aa:bb:cc:dd:ee:ff")];
96
97    snprintf(bridge_id_str, sizeof(bridge_id_str),
98             "%.2x%.2x.%.2x:%.2x:%.2x:%.2x:%.2x:%.2x",
99             p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]);
100
101    return bridge_id_str;
102}
103
104static void
105stp_print_config_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu,
106                      u_int length)
107{
108    ND_PRINT((ndo, ", Flags [%s]",
109           bittok2str(stp_bpdu_flag_values, "none", stp_bpdu->flags)));
110
111    ND_PRINT((ndo, ", bridge-id %s.%04x, length %u",
112           stp_print_bridge_id((const u_char *)&stp_bpdu->bridge_id),
113           EXTRACT_16BITS(&stp_bpdu->port_id), length));
114
115    /* in non-verbose mode just print the bridge-id */
116    if (!ndo->ndo_vflag) {
117        return;
118    }
119
120    ND_PRINT((ndo, "\n\tmessage-age %.2fs, max-age %.2fs"
121           ", hello-time %.2fs, forwarding-delay %.2fs",
122           (float)EXTRACT_16BITS(&stp_bpdu->message_age) / STP_TIME_BASE,
123           (float)EXTRACT_16BITS(&stp_bpdu->max_age) / STP_TIME_BASE,
124           (float)EXTRACT_16BITS(&stp_bpdu->hello_time) / STP_TIME_BASE,
125           (float)EXTRACT_16BITS(&stp_bpdu->forward_delay) / STP_TIME_BASE));
126
127    ND_PRINT((ndo, "\n\troot-id %s, root-pathcost %u",
128           stp_print_bridge_id((const u_char *)&stp_bpdu->root_id),
129           EXTRACT_32BITS(&stp_bpdu->root_path_cost)));
130
131    /* Port role is only valid for 802.1w */
132    if (stp_bpdu->protocol_version == STP_PROTO_RAPID) {
133        ND_PRINT((ndo, ", port-role %s",
134               tok2str(rstp_obj_port_role_values, "Unknown",
135                       RSTP_EXTRACT_PORT_ROLE(stp_bpdu->flags))));
136    }
137}
138
139/*
140 * MSTP packet format
141 * Ref. IEEE 802.1Q 2003 Ed. Section 14
142 *
143 * MSTP BPDU
144 *
145 * 2 -  bytes Protocol Id
146 * 1 -  byte  Protocol Ver.
147 * 1 -  byte  BPDU tye
148 * 1 -  byte  Flags
149 * 8 -  bytes CIST Root Identifier
150 * 4 -  bytes CIST External Path Cost
151 * 8 -  bytes CIST Regional Root Identifier
152 * 2 -  bytes CIST Port Identifier
153 * 2 -  bytes Message Age
154 * 2 -  bytes Max age
155 * 2 -  bytes Hello Time
156 * 2 -  bytes Forward delay
157 * 1 -  byte  Version 1 length. Must be 0
158 * 2 -  bytes Version 3 length
159 * 1 -  byte  Config Identifier
160 * 32 - bytes Config Name
161 * 2 -  bytes Revision level
162 * 16 - bytes Config Digest [MD5]
163 * 4 -  bytes CIST Internal Root Path Cost
164 * 8 -  bytes CIST Bridge Identifier
165 * 1 -  byte  CIST Remaining Hops
166 * 16 - bytes MSTI information [Max 64 MSTI, each 16 bytes]
167 *
168 *
169 * SPB BPDU
170 * Ref. IEEE 802.1aq. Section 14
171 *
172 * 2 -  bytes Version 4 length
173 * 1 -  byte  Aux Config Identifier
174 * 32 - bytes Aux Config Name
175 * 2 -  bytes Aux Revision level
176 * 16 - bytes Aux Config Digest [MD5]
177 * 1 -  byte  (1 - 2) Agreement Number
178 *            (3 - 4) Discarded Agreement Number
179 *            (5) Agreement Valid Flag
180 *            (6) Restricted Role Flag
181 *            (7 - 8) Unused sent zero
182 * 1 -  byte Unused
183 * 1 -  byte (1 - 4) Agreement Digest Format Identifier
184 *           (5 - 8) Agreement Digest Format Capabilities
185 * 1 -  byte (1 - 4) Agreement Digest Convention Identifier
186 *           (5 - 8) Agreement Digest Convention Capabilities
187 * 2 -  bytes Agreement Digest Edge Count
188 * 8 -  byte Reserved Set
189 * 20 - bytes Computed Topology Digest
190 *
191 *
192 * MSTI Payload
193 *
194 * 1 - byte  MSTI flag
195 * 8 - bytes MSTI Regional Root Identifier
196 * 4 - bytes MSTI Regional Path Cost
197 * 1 - byte  MSTI Bridge Priority
198 * 1 - byte  MSTI Port Priority
199 * 1 - byte  MSTI Remaining Hops
200 *
201 */
202
203#define MST_BPDU_MSTI_LENGTH		    16
204#define MST_BPDU_CONFIG_INFO_LENGTH	    64
205
206/* Offsets of fields from the begginning for the packet */
207#define MST_BPDU_VER3_LEN_OFFSET	    36
208#define MST_BPDU_CONFIG_NAME_OFFSET	    39
209#define MST_BPDU_CONFIG_DIGEST_OFFSET	    73
210#define MST_BPDU_CIST_INT_PATH_COST_OFFSET  89
211#define MST_BPDU_CIST_BRIDGE_ID_OFFSET	    93
212#define MST_BPDU_CIST_REMAIN_HOPS_OFFSET    101
213#define MST_BPDU_MSTI_OFFSET		    102
214/* Offsets within  an MSTI */
215#define MST_BPDU_MSTI_ROOT_PRIO_OFFSET	    1
216#define MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET 9
217#define MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET    13
218#define MST_BPDU_MSTI_PORT_PRIO_OFFSET	    14
219#define MST_BPDU_MSTI_REMAIN_HOPS_OFFSET    15
220
221#define SPB_BPDU_MIN_LEN                  87
222#define SPB_BPDU_CONFIG_NAME_OFFSET       3
223#define SPB_BPDU_CONFIG_REV_OFFSET        SPB_BPDU_CONFIG_NAME_OFFSET + 32
224#define SPB_BPDU_CONFIG_DIGEST_OFFSET     SPB_BPDU_CONFIG_REV_OFFSET + 2
225#define SPB_BPDU_AGREEMENT_OFFSET         SPB_BPDU_CONFIG_DIGEST_OFFSET + 16
226#define SPB_BPDU_AGREEMENT_UNUSED_OFFSET  SPB_BPDU_AGREEMENT_OFFSET + 1
227#define SPB_BPDU_AGREEMENT_FORMAT_OFFSET  SPB_BPDU_AGREEMENT_UNUSED_OFFSET + 1
228#define SPB_BPDU_AGREEMENT_CON_OFFSET     SPB_BPDU_AGREEMENT_FORMAT_OFFSET + 1
229#define SPB_BPDU_AGREEMENT_EDGE_OFFSET    SPB_BPDU_AGREEMENT_CON_OFFSET + 1
230#define SPB_BPDU_AGREEMENT_RES1_OFFSET    SPB_BPDU_AGREEMENT_EDGE_OFFSET + 2
231#define SPB_BPDU_AGREEMENT_RES2_OFFSET    SPB_BPDU_AGREEMENT_RES1_OFFSET + 4
232#define SPB_BPDU_AGREEMENT_DIGEST_OFFSET  SPB_BPDU_AGREEMENT_RES2_OFFSET + 4
233
234
235static void
236stp_print_mstp_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu,
237                    u_int length)
238{
239    const u_char *ptr;
240    uint16_t	    v3len;
241    uint16_t	    len;
242    uint16_t	    msti;
243    u_int	    offset;
244
245    ptr = (const u_char *)stp_bpdu;
246    ND_PRINT((ndo, ", CIST Flags [%s], length %u",
247           bittok2str(stp_bpdu_flag_values, "none", stp_bpdu->flags), length));
248
249    /*
250     * in non-verbose mode just print the flags.
251     */
252    if (!ndo->ndo_vflag) {
253        return;
254    }
255
256    ND_PRINT((ndo, "\n\tport-role %s, ",
257           tok2str(rstp_obj_port_role_values, "Unknown",
258                   RSTP_EXTRACT_PORT_ROLE(stp_bpdu->flags))));
259
260    ND_PRINT((ndo, "CIST root-id %s, CIST ext-pathcost %u ",
261           stp_print_bridge_id((const u_char *)&stp_bpdu->root_id),
262           EXTRACT_32BITS(&stp_bpdu->root_path_cost)));
263
264    ND_PRINT((ndo, "\n\tCIST regional-root-id %s, ",
265           stp_print_bridge_id((const u_char *)&stp_bpdu->bridge_id)));
266
267    ND_PRINT((ndo, "CIST port-id %04x, ", EXTRACT_16BITS(&stp_bpdu->port_id)));
268
269    ND_PRINT((ndo, "\n\tmessage-age %.2fs, max-age %.2fs"
270           ", hello-time %.2fs, forwarding-delay %.2fs",
271           (float)EXTRACT_16BITS(&stp_bpdu->message_age) / STP_TIME_BASE,
272           (float)EXTRACT_16BITS(&stp_bpdu->max_age) / STP_TIME_BASE,
273           (float)EXTRACT_16BITS(&stp_bpdu->hello_time) / STP_TIME_BASE,
274           (float)EXTRACT_16BITS(&stp_bpdu->forward_delay) / STP_TIME_BASE));
275
276    ND_PRINT((ndo, "\n\tv3len %d, ", EXTRACT_16BITS(ptr + MST_BPDU_VER3_LEN_OFFSET)));
277    ND_PRINT((ndo, "MCID Name %s, rev %u, "
278            "\n\t\tdigest %08x%08x%08x%08x, ",
279            ptr + MST_BPDU_CONFIG_NAME_OFFSET,
280	          EXTRACT_16BITS(ptr + MST_BPDU_CONFIG_NAME_OFFSET + 32),
281      	    EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET),
282        	  EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 4),
283	          EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 8),
284	          EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 12)));
285
286    ND_PRINT((ndo, "CIST int-root-pathcost %u, ",
287            EXTRACT_32BITS(ptr + MST_BPDU_CIST_INT_PATH_COST_OFFSET)));
288
289    ND_PRINT((ndo, "\n\tCIST bridge-id %s, ",
290           stp_print_bridge_id(ptr + MST_BPDU_CIST_BRIDGE_ID_OFFSET)));
291
292    ND_PRINT((ndo, "CIST remaining-hops %d", ptr[MST_BPDU_CIST_REMAIN_HOPS_OFFSET]));
293
294    /* Dump all MSTI's */
295    v3len = EXTRACT_16BITS(ptr + MST_BPDU_VER3_LEN_OFFSET);
296    if (v3len > MST_BPDU_CONFIG_INFO_LENGTH) {
297        len = v3len - MST_BPDU_CONFIG_INFO_LENGTH;
298        offset = MST_BPDU_MSTI_OFFSET;
299        while (len >= MST_BPDU_MSTI_LENGTH) {
300            msti = EXTRACT_16BITS(ptr + offset +
301                                  MST_BPDU_MSTI_ROOT_PRIO_OFFSET);
302            msti = msti & 0x0FFF;
303
304            ND_PRINT((ndo, "\n\tMSTI %d, Flags [%s], port-role %s",
305                   msti, bittok2str(stp_bpdu_flag_values, "none", ptr[offset]),
306                   tok2str(rstp_obj_port_role_values, "Unknown",
307                           RSTP_EXTRACT_PORT_ROLE(ptr[offset]))));
308            ND_PRINT((ndo, "\n\t\tMSTI regional-root-id %s, pathcost %u",
309                   stp_print_bridge_id(ptr + offset +
310                                       MST_BPDU_MSTI_ROOT_PRIO_OFFSET),
311                   EXTRACT_32BITS(ptr + offset +
312                                  MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET)));
313            ND_PRINT((ndo, "\n\t\tMSTI bridge-prio %d, port-prio %d, hops %d",
314                   ptr[offset + MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET] >> 4,
315                   ptr[offset + MST_BPDU_MSTI_PORT_PRIO_OFFSET] >> 4,
316                   ptr[offset + MST_BPDU_MSTI_REMAIN_HOPS_OFFSET]));
317
318            len -= MST_BPDU_MSTI_LENGTH;
319            offset += MST_BPDU_MSTI_LENGTH;
320        }
321    }
322}
323
324static void
325stp_print_spb_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu,
326                   u_int offset)
327{
328    const u_char *ptr;
329
330    /*
331     * in non-verbose mode don't print anything.
332     */
333    if (!ndo->ndo_vflag) {
334        return;
335    }
336
337    ptr = (const u_char *)stp_bpdu;
338    ND_PRINT((ndo, "\n\tv4len %d AUXMCID Name %s, Rev %u, \n\t\tdigest %08x%08x%08x%08x",
339            EXTRACT_16BITS (ptr + offset),
340            ptr + offset + SPB_BPDU_CONFIG_NAME_OFFSET,
341            EXTRACT_16BITS(ptr + offset + SPB_BPDU_CONFIG_REV_OFFSET),
342            EXTRACT_32BITS(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET),
343            EXTRACT_32BITS(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 4),
344            EXTRACT_32BITS(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 8),
345            EXTRACT_32BITS(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 12)));
346
347    ND_PRINT((ndo, "\n\tAgreement num %d, Discarded Agreement num %d, Agreement valid-"
348            "flag %d, \n\tRestricted role-flag: %d, Format id %d cap %d, "
349            "Convention id %d cap %d, \n\tEdge count %d, "
350            "Agreement digest %08x%08x%08x%08x%08x\n",
351            ptr[offset + SPB_BPDU_AGREEMENT_OFFSET]>>6,
352            ptr[offset + SPB_BPDU_AGREEMENT_OFFSET]>>4 & 0x3,
353            ptr[offset + SPB_BPDU_AGREEMENT_OFFSET]>>3 & 0x1,
354            ptr[offset + SPB_BPDU_AGREEMENT_OFFSET]>>2 & 0x1,
355            ptr[offset + SPB_BPDU_AGREEMENT_FORMAT_OFFSET]>>4,
356            ptr[offset + SPB_BPDU_AGREEMENT_FORMAT_OFFSET]&0x00ff,
357            ptr[offset + SPB_BPDU_AGREEMENT_CON_OFFSET]>>4,
358            ptr[offset + SPB_BPDU_AGREEMENT_CON_OFFSET]&0x00ff,
359            EXTRACT_16BITS(ptr + offset + SPB_BPDU_AGREEMENT_EDGE_OFFSET),
360            EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET),
361            EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET)+4,
362            EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET)+8,
363            EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET)+12,
364            EXTRACT_32BITS(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET)+16));
365}
366
367/*
368 * Print 802.1d / 802.1w / 802.1q (mstp) / 802.1aq (spb) packets.
369 */
370void
371stp_print(netdissect_options *ndo, const u_char *p, u_int length)
372{
373    const struct stp_bpdu_ *stp_bpdu;
374    u_int                  mstp_len;
375    u_int                  spb_len;
376
377    stp_bpdu = (struct stp_bpdu_*)p;
378
379    /* Minimum STP Frame size. */
380    if (length < 4)
381        goto trunc;
382
383    if (EXTRACT_16BITS(&stp_bpdu->protocol_id)) {
384        ND_PRINT((ndo, "unknown STP version, length %u", length));
385        return;
386    }
387
388    ND_PRINT((ndo, "STP %s", tok2str(stp_proto_values, "Unknown STP protocol (0x%02x)",
389                         stp_bpdu->protocol_version)));
390
391    switch (stp_bpdu->protocol_version) {
392    case STP_PROTO_REGULAR:
393    case STP_PROTO_RAPID:
394    case STP_PROTO_MSTP:
395    case STP_PROTO_SPB:
396        break;
397    default:
398        return;
399    }
400
401    ND_PRINT((ndo, ", %s", tok2str(stp_bpdu_type_values, "Unknown BPDU Type (0x%02x)",
402                           stp_bpdu->bpdu_type)));
403
404    switch (stp_bpdu->bpdu_type) {
405    case STP_BPDU_TYPE_CONFIG:
406        if (length < sizeof(struct stp_bpdu_) - 1) {
407            goto trunc;
408        }
409        stp_print_config_bpdu(ndo, stp_bpdu, length);
410        break;
411
412    case STP_BPDU_TYPE_RSTP:
413        if (stp_bpdu->protocol_version == STP_PROTO_RAPID) {
414            if (length < sizeof(struct stp_bpdu_)) {
415                goto trunc;
416            }
417            stp_print_config_bpdu(ndo, stp_bpdu, length);
418        } else if (stp_bpdu->protocol_version == STP_PROTO_MSTP ||
419                   stp_bpdu->protocol_version == STP_PROTO_SPB) {
420            if (length < STP_BPDU_MSTP_MIN_LEN) {
421                goto trunc;
422            }
423
424            if (stp_bpdu->v1_length != 0) {
425                /* FIX ME: Emit a message here ? */
426                goto trunc;
427            }
428
429            /* Validate v3 length */
430            mstp_len = EXTRACT_16BITS(p + MST_BPDU_VER3_LEN_OFFSET);
431            mstp_len += 2;  /* length encoding itself is 2 bytes */
432            if (length < (sizeof(struct stp_bpdu_) + mstp_len)) {
433                goto trunc;
434            }
435            stp_print_mstp_bpdu(ndo, stp_bpdu, length);
436
437            if (stp_bpdu->protocol_version == STP_PROTO_SPB)
438            {
439              /* Validate v4 length */
440              spb_len = EXTRACT_16BITS (p + MST_BPDU_VER3_LEN_OFFSET + mstp_len);
441              spb_len += 2;
442              if (length < (sizeof(struct stp_bpdu_) + mstp_len + spb_len) ||
443                  spb_len < SPB_BPDU_MIN_LEN) {
444                goto trunc;
445              }
446              stp_print_spb_bpdu(ndo, stp_bpdu, (sizeof(struct stp_bpdu_) + mstp_len));
447            }
448        }
449        break;
450
451    case STP_BPDU_TYPE_TOPO_CHANGE:
452        /* always empty message - just break out */
453        break;
454
455    default:
456        break;
457    }
458
459    return;
460 trunc:
461    ND_PRINT((ndo, "[|stp %d]", length));
462}
463
464/*
465 * Local Variables:
466 * c-style: whitesmith
467 * c-basic-offset: 4
468 * End:
469 */
470