xref: /freebsd/contrib/tcpdump/print-stp.c (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
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 #ifndef lint
13 static const char rcsid[] _U_ =
14 "@(#) $Header: /tcpdump/master/tcpdump/print-stp.c,v 1.13.2.7 2007/03/18 17:12:36 hannes Exp $";
15 #endif
16 
17 #ifdef HAVE_CONFIG_H
18 #include "config.h"
19 #endif
20 
21 #include <tcpdump-stdinc.h>
22 
23 #include <stdlib.h>
24 #include <stdio.h>
25 #include <string.h>
26 
27 #include "interface.h"
28 #include "addrtoname.h"
29 #include "extract.h"
30 
31 #define	RSTP_EXTRACT_PORT_ROLE(x) (((x)&0x0C)>>2)
32 /* STP timers are expressed in multiples of 1/256th second */
33 #define STP_TIME_BASE 256
34 #define STP_BPDU_MSTP_MIN_LEN 102
35 
36 struct stp_bpdu_ {
37     u_int8_t protocol_id[2];
38     u_int8_t protocol_version;
39     u_int8_t bpdu_type;
40     u_int8_t flags;
41     u_int8_t root_id[8];
42     u_int8_t root_path_cost[4];
43     u_int8_t bridge_id[8];
44     u_int8_t port_id[2];
45     u_int8_t message_age[2];
46     u_int8_t max_age[2];
47     u_int8_t hello_time[2];
48     u_int8_t forward_delay[2];
49     u_int8_t v1_length;
50 };
51 
52 #define STP_PROTO_REGULAR 0x00
53 #define STP_PROTO_RAPID   0x02
54 #define STP_PROTO_MSTP    0x03
55 
56 struct tok stp_proto_values[] = {
57     { STP_PROTO_REGULAR, "802.1d" },
58     { STP_PROTO_RAPID, "802.1w" },
59     { STP_PROTO_MSTP, "802.1s" },
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 
67 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 
77 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 
84 struct tok rstp_obj_port_role_values[] = {
85     { 0x00, "Unknown" },
86     { 0x01, "Alternate" },
87     { 0x02, "Root" },
88     { 0x03, "Designated" },
89     { 0, NULL}
90 };
91 
92 static char *
93 stp_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 
104 static void
105 stp_print_config_bpdu(const struct stp_bpdu_ *stp_bpdu, u_int length)
106 {
107     printf(", Flags [%s]",
108            bittok2str(stp_bpdu_flag_values, "none", stp_bpdu->flags));
109 
110     printf(", bridge-id %s.%04x, length %u",
111            stp_print_bridge_id((const u_char *)&stp_bpdu->bridge_id),
112            EXTRACT_16BITS(&stp_bpdu->port_id), length);
113 
114     /* in non-verbose mode just print the bridge-id */
115     if (!vflag) {
116         return;
117     }
118 
119     printf("\n\tmessage-age %.2fs, max-age %.2fs"
120            ", hello-time %.2fs, forwarding-delay %.2fs",
121            (float)EXTRACT_16BITS(&stp_bpdu->message_age) / STP_TIME_BASE,
122            (float)EXTRACT_16BITS(&stp_bpdu->max_age) / STP_TIME_BASE,
123            (float)EXTRACT_16BITS(&stp_bpdu->hello_time) / STP_TIME_BASE,
124            (float)EXTRACT_16BITS(&stp_bpdu->forward_delay) / STP_TIME_BASE);
125 
126     printf("\n\troot-id %s, root-pathcost %u",
127            stp_print_bridge_id((const u_char *)&stp_bpdu->root_id),
128            EXTRACT_32BITS(&stp_bpdu->root_path_cost));
129 
130     /* Port role is only valid for 802.1w */
131     if (stp_bpdu->protocol_version == STP_PROTO_RAPID) {
132         printf(", port-role %s",
133                tok2str(rstp_obj_port_role_values, "Unknown",
134                        RSTP_EXTRACT_PORT_ROLE(stp_bpdu->flags)));
135     }
136 }
137 
138 /*
139  * MSTP packet format
140  * Ref. IEEE 802.1Q 2003 Ed. Section 14
141  *
142  * MSTP BPDU
143  *
144  * 2 -  bytes Protocol Id
145  * 1 -  byte  Protocol Ver.
146  * 1 -  byte  BPDU tye
147  * 1 -  byte  Flags
148  * 8 -  bytes CIST Root Identifier
149  * 4 -  bytes CIST External Path Cost
150  * 8 -  bytes CIST Regional Root Identifier
151  * 2 -  bytes CIST Port Identifier
152  * 2 -  bytes Message Age
153  * 2 -  bytes Max age
154  * 2 -  bytes Hello Time
155  * 2 -  bytes Forward delay
156  * 1 -  byte  Version 1 length. Must be 0
157  * 2 -  bytes Version 3 length
158  * 1 -  byte  Config Identifier
159  * 32 - bytes Config Name
160  * 2 -  bytes Revision level
161  * 16 - bytes Config Digest [MD5]
162  * 4 -  bytes CIST Internal Root Path Cost
163  * 8 -  bytes CIST Bridge Identifier
164  * 1 -  byte  CIST Remaining Hops
165  * 16 - bytes MSTI information [Max 64 MSTI, each 16 bytes]
166  *
167  * MSTI Payload
168  *
169  * 1 - byte  MSTI flag
170  * 8 - bytes MSTI Regional Root Identifier
171  * 4 - bytes MSTI Regional Path Cost
172  * 1 - byte  MSTI Bridge Priority
173  * 1 - byte  MSTI Port Priority
174  * 1 - byte  MSTI Remaining Hops
175  */
176 
177 #define MST_BPDU_MSTI_LENGTH		    16
178 #define MST_BPDU_CONFIG_INFO_LENGTH	    64
179 
180 /* Offsets of fields from the begginning for the packet */
181 #define MST_BPDU_VER3_LEN_OFFSET	    36
182 #define MST_BPDU_CONFIG_NAME_OFFSET	    39
183 #define MST_BPDU_CONFIG_DIGEST_OFFSET	    73
184 #define MST_BPDU_CIST_INT_PATH_COST_OFFSET  89
185 #define MST_BPDU_CIST_BRIDGE_ID_OFFSET	    93
186 #define MST_BPDU_CIST_REMAIN_HOPS_OFFSET    101
187 #define MST_BPDU_MSTI_OFFSET		    102
188 /* Offsets within  an MSTI */
189 #define MST_BPDU_MSTI_ROOT_PRIO_OFFSET	    1
190 #define MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET 9
191 #define MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET    13
192 #define MST_BPDU_MSTI_PORT_PRIO_OFFSET	    14
193 #define MST_BPDU_MSTI_REMAIN_HOPS_OFFSET    15
194 
195 static void
196 stp_print_mstp_bpdu(const struct stp_bpdu_ *stp_bpdu, u_int length)
197 {
198     const u_char    *ptr;
199     u_int16_t	    v3len;
200     u_int16_t	    len;
201     u_int16_t	    msti;
202     u_int16_t	    offset;
203 
204     ptr = (const u_char *)stp_bpdu;
205     printf(", CIST Flags [%s]",
206            bittok2str(stp_bpdu_flag_values, "none", stp_bpdu->flags));
207 
208     /*
209      * in non-verbose mode just print the flags. We dont read that much
210      * of the packet (DEFAULT_SNAPLEN) to print out cist bridge-id
211      */
212     if (!vflag) {
213         return;
214     }
215 
216     printf(", CIST bridge-id %s.%04x, length %u",
217            stp_print_bridge_id(ptr + MST_BPDU_CIST_BRIDGE_ID_OFFSET),
218            EXTRACT_16BITS(&stp_bpdu->port_id), length);
219 
220 
221     printf("\n\tmessage-age %.2fs, max-age %.2fs"
222            ", hello-time %.2fs, forwarding-delay %.2fs",
223            (float)EXTRACT_16BITS(&stp_bpdu->message_age) / STP_TIME_BASE,
224            (float)EXTRACT_16BITS(&stp_bpdu->max_age) / STP_TIME_BASE,
225            (float)EXTRACT_16BITS(&stp_bpdu->hello_time) / STP_TIME_BASE,
226            (float)EXTRACT_16BITS(&stp_bpdu->forward_delay) / STP_TIME_BASE);
227 
228     printf("\n\tCIST root-id %s, ext-pathcost %u int-pathcost %u",
229            stp_print_bridge_id((const u_char *)&stp_bpdu->root_id),
230            EXTRACT_32BITS(&stp_bpdu->root_path_cost),
231            EXTRACT_32BITS(ptr + MST_BPDU_CIST_INT_PATH_COST_OFFSET));
232 
233     printf(", port-role %s",
234            tok2str(rstp_obj_port_role_values, "Unknown",
235                    RSTP_EXTRACT_PORT_ROLE(stp_bpdu->flags)));
236 
237     printf("\n\tCIST regional-root-id %s",
238            stp_print_bridge_id((const u_char *)&stp_bpdu->bridge_id));
239 
240     printf("\n\tMSTP Configuration Name %s, revision %u, digest %08x%08x%08x%08x",
241            ptr + MST_BPDU_CONFIG_NAME_OFFSET,
242 	   EXTRACT_16BITS(ptr + MST_BPDU_CONFIG_NAME_OFFSET + 32),
243 	   EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET),
244 	   EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 4),
245 	   EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 8),
246 	   EXTRACT_32BITS(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 12));
247 
248     printf("\n\tCIST remaining-hops %d", ptr[MST_BPDU_CIST_REMAIN_HOPS_OFFSET]);
249 
250     /* Dump all MSTI's */
251     v3len = EXTRACT_16BITS(ptr + MST_BPDU_VER3_LEN_OFFSET);
252     if (v3len > MST_BPDU_CONFIG_INFO_LENGTH) {
253         len = v3len - MST_BPDU_CONFIG_INFO_LENGTH;
254         offset = MST_BPDU_MSTI_OFFSET;
255         while (len >= MST_BPDU_MSTI_LENGTH) {
256             msti = EXTRACT_16BITS(ptr + offset +
257                                   MST_BPDU_MSTI_ROOT_PRIO_OFFSET);
258             msti = msti & 0x0FFF;
259 
260             printf("\n\tMSTI %d, Flags [%s], port-role %s",
261                    msti, bittok2str(stp_bpdu_flag_values, "none", ptr[offset]),
262                    tok2str(rstp_obj_port_role_values, "Unknown",
263                            RSTP_EXTRACT_PORT_ROLE(ptr[offset])));
264             printf("\n\t\tMSTI regional-root-id %s, pathcost %u",
265                    stp_print_bridge_id(ptr + offset +
266                                        MST_BPDU_MSTI_ROOT_PRIO_OFFSET),
267                    EXTRACT_32BITS(ptr + offset +
268                                   MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET));
269             printf("\n\t\tMSTI bridge-prio %d, port-prio %d, hops %d",
270                    ptr[offset + MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET] >> 4,
271                    ptr[offset + MST_BPDU_MSTI_PORT_PRIO_OFFSET] >> 4,
272                    ptr[offset + MST_BPDU_MSTI_REMAIN_HOPS_OFFSET]);
273 
274             len -= MST_BPDU_MSTI_LENGTH;
275             offset += MST_BPDU_MSTI_LENGTH;
276         }
277     }
278 }
279 
280 /*
281  * Print 802.1d / 802.1w / 802.1q (mstp) packets.
282  */
283 void
284 stp_print(const u_char *p, u_int length)
285 {
286     const struct stp_bpdu_ *stp_bpdu;
287     u_int16_t              mstp_len;
288 
289     stp_bpdu = (struct stp_bpdu_*)p;
290 
291     /* Minimum STP Frame size. */
292     if (length < 4)
293         goto trunc;
294 
295     if (EXTRACT_16BITS(&stp_bpdu->protocol_id)) {
296         printf("unknown STP version, length %u", length);
297         return;
298     }
299 
300     printf("STP %s", tok2str(stp_proto_values, "Unknown STP protocol (0x%02x)",
301                          stp_bpdu->protocol_version));
302 
303     switch (stp_bpdu->protocol_version) {
304     case STP_PROTO_REGULAR:
305     case STP_PROTO_RAPID:
306     case STP_PROTO_MSTP:
307         break;
308     default:
309         return;
310     }
311 
312     printf(", %s", tok2str(stp_bpdu_type_values, "Unknown BPDU Type (0x%02x)",
313                            stp_bpdu->bpdu_type));
314 
315     switch (stp_bpdu->bpdu_type) {
316     case STP_BPDU_TYPE_CONFIG:
317         if (length < sizeof(struct stp_bpdu_) - 1) {
318             goto trunc;
319         }
320         stp_print_config_bpdu(stp_bpdu, length);
321         break;
322 
323     case STP_BPDU_TYPE_RSTP:
324         if (stp_bpdu->protocol_version == STP_PROTO_RAPID) {
325             if (length < sizeof(struct stp_bpdu_)) {
326                 goto trunc;
327             }
328             stp_print_config_bpdu(stp_bpdu, length);
329         } else if (stp_bpdu->protocol_version == STP_PROTO_MSTP) {
330             if (length < STP_BPDU_MSTP_MIN_LEN) {
331                 goto trunc;
332             }
333             if (stp_bpdu->v1_length != 0) {
334                 /* FIX ME: Emit a message here ? */
335                 goto trunc;
336             }
337             /* Validate v3 length */
338             mstp_len = EXTRACT_16BITS(p + MST_BPDU_VER3_LEN_OFFSET);
339             mstp_len += 2;  /* length encoding itself is 2 bytes */
340             if (length < (sizeof(struct stp_bpdu_) + mstp_len)) {
341                 goto trunc;
342             }
343             stp_print_mstp_bpdu(stp_bpdu, length);
344         }
345         break;
346 
347     case STP_BPDU_TYPE_TOPO_CHANGE:
348         /* always empty message - just break out */
349         break;
350 
351     default:
352         break;
353     }
354 
355     return;
356  trunc:
357     printf("[|stp %d]", length);
358 }
359 
360 /*
361  * Local Variables:
362  * c-style: whitesmith
363  * c-basic-offset: 4
364  * End:
365  */
366