The Tcpdump Group git mirrors - tcpdump/blob - print-stp.c

   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 1.13.2.5 2007-03-08 13:53:35 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_CIST_INT_PATH_COST_OFFSET  89
 184 #define MST_BPDU_CIST_BRIDGE_ID_OFFSET      93
 185 #define MST_BPDU_CIST_REMAIN_HOPS_OFFSET    101
 186 #define MST_BPDU_MSTI_OFFSET                102
 187 /* Offsets within  an MSTI */
 188 #define MST_BPDU_MSTI_ROOT_PRIO_OFFSET      1
 189 #define MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET 9
 190 #define MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET    13
 191 #define MST_BPDU_MSTI_PORT_PRIO_OFFSET      14
 192 #define MST_BPDU_MSTI_REMAIN_HOPS_OFFSET    15
 193
 194 static void
 195 stp_print_mstp_bpdu(const struct stp_bpdu_ *stp_bpdu, u_int length)
 196 {
 197     const u_char    *ptr;
 198     u_int16_t       v3len;
 199     u_int16_t       len;
 200     u_int16_t       msti;
 201     u_int16_t       offset;
 202
 203     ptr = (const u_char *)stp_bpdu;
 204     printf(", CIST Flags [%s]",
 205            bittok2str(stp_bpdu_flag_values, "none", stp_bpdu->flags));
 206
 207     /*
 208      * in non-verbose mode just print the flags. We dont read that much
 209      * of the packet (DEFAULT_SNAPLEN) to print out cist bridge-id
 210      */
 211     if (!vflag) {
 212         return;
 213     }
 214
 215     printf(", CIST bridge-id %s.%04x, length %u",
 216            stp_print_bridge_id(ptr + MST_BPDU_CIST_BRIDGE_ID_OFFSET),
 217            EXTRACT_16BITS(&stp_bpdu->port_id), length);
 218
 219
 220     printf("\n\tmessage-age %.2fs, max-age %.2fs"
 221            ", hello-time %.2fs, forwarding-delay %.2fs",
 222            (float)EXTRACT_16BITS(&stp_bpdu->message_age) / STP_TIME_BASE,
 223            (float)EXTRACT_16BITS(&stp_bpdu->max_age) / STP_TIME_BASE,
 224            (float)EXTRACT_16BITS(&stp_bpdu->hello_time) / STP_TIME_BASE,
 225            (float)EXTRACT_16BITS(&stp_bpdu->forward_delay) / STP_TIME_BASE);
 226
 227     printf("\n\tCIST root-id %s, ext-pathcost %u int-pathcost %u",
 228            stp_print_bridge_id((const u_char *)&stp_bpdu->root_id),
 229            EXTRACT_32BITS(&stp_bpdu->root_path_cost),
 230            EXTRACT_32BITS(ptr + MST_BPDU_CIST_INT_PATH_COST_OFFSET));
 231
 232     printf(", port-role %s",
 233            tok2str(rstp_obj_port_role_values, "Unknown",
 234                    RSTP_EXTRACT_PORT_ROLE(stp_bpdu->flags)));
 235
 236     printf("\n\tCIST regional-root-id %s",
 237            stp_print_bridge_id((const u_char *)&stp_bpdu->bridge_id));
 238
 239     printf("\n\tMSTP Configuration Name %s",
 240            ptr + MST_BPDU_CONFIG_NAME_OFFSET);
 241
 242     printf("\n\tCIST remaining-hops %d", ptr[MST_BPDU_CIST_REMAIN_HOPS_OFFSET]);
 243
 244     /* Dump all MSTI's */
 245     v3len = EXTRACT_16BITS(ptr + MST_BPDU_VER3_LEN_OFFSET);
 246     if (v3len > MST_BPDU_CONFIG_INFO_LENGTH) {
 247         len = v3len - MST_BPDU_CONFIG_INFO_LENGTH;
 248         offset = MST_BPDU_MSTI_OFFSET;
 249         while (len >= MST_BPDU_MSTI_LENGTH) {
 250             msti = EXTRACT_16BITS(ptr + offset +
 251                                   MST_BPDU_MSTI_ROOT_PRIO_OFFSET);
 252             msti = msti & 0x0FFF;
 253
 254             printf("\n\tMSTI %d, Flags [%s], port-role %s",
 255                    msti, bittok2str(stp_bpdu_flag_values, "none", ptr[offset]),
 256                    tok2str(rstp_obj_port_role_values, "Unknown",
 257                            RSTP_EXTRACT_PORT_ROLE(ptr[offset])));
 258             printf("\n\t\tMSTI regional-root-id %s, pathcost %u",
 259                    stp_print_bridge_id(ptr + offset +
 260                                        MST_BPDU_MSTI_ROOT_PRIO_OFFSET),
 261                    EXTRACT_32BITS(ptr + offset +
 262                                   MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET));
 263             printf("\n\t\tMSTI bridge-prio %d, port-prio %d, hops %d",
 264                    ptr[offset + MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET],
 265                    ptr[offset + MST_BPDU_MSTI_PORT_PRIO_OFFSET],
 266                    ptr[offset + MST_BPDU_MSTI_REMAIN_HOPS_OFFSET]);
 267
 268             len -= MST_BPDU_MSTI_LENGTH;
 269             offset += MST_BPDU_MSTI_LENGTH;
 270         }
 271     }
 272 }
 273
 274 /*
 275  * Print 802.1d / 802.1w / 802.1q (mstp) packets.
 276  */
 277 void
 278 stp_print(const u_char *p, u_int length)
 279 {
 280     const struct stp_bpdu_ *stp_bpdu;
 281     u_int16_t              mstp_len;
 282
 283     stp_bpdu = (struct stp_bpdu_*)p;
 284
 285     /* Minimum STP Frame size. */
 286     if (length < 4)
 287         goto trunc;
 288
 289     if (EXTRACT_16BITS(&stp_bpdu->protocol_id)) {
 290         printf("unknown STP version, length %u", length);
 291         return;
 292     }
 293
 294     printf("STP %s", tok2str(stp_proto_values, "Unknown STP protocol (0x%02x)",
 295                          stp_bpdu->protocol_version));
 296
 297     switch (stp_bpdu->protocol_version) {
 298     case STP_PROTO_REGULAR:
 299     case STP_PROTO_RAPID:
 300     case STP_PROTO_MSTP:
 301         break;
 302     default:
 303         return;
 304     }
 305
 306     printf(", %s", tok2str(stp_bpdu_type_values, "Unknown BPDU Type (0x%02x)",
 307                            stp_bpdu->bpdu_type));
 308
 309     switch (stp_bpdu->bpdu_type) {
 310     case STP_BPDU_TYPE_CONFIG:
 311         if (length < sizeof(struct stp_bpdu_) - 1) {
 312             goto trunc;
 313         }
 314         stp_print_config_bpdu(stp_bpdu, length);
 315         break;
 316
 317     case STP_BPDU_TYPE_RSTP:
 318         if (stp_bpdu->protocol_version == STP_PROTO_RAPID) {
 319             if (length < sizeof(struct stp_bpdu_)) {
 320                 goto trunc;
 321             }
 322             stp_print_config_bpdu(stp_bpdu, length);
 323         } else if (stp_bpdu->protocol_version == STP_PROTO_MSTP) {
 324             if (length < STP_BPDU_MSTP_MIN_LEN) {
 325                 goto trunc;
 326             }
 327             if (stp_bpdu->v1_length != 0) {
 328                 /* FIX ME: Emit a message here ? */
 329                 goto trunc;
 330             }
 331             /* Validate v3 length */
 332             mstp_len = EXTRACT_16BITS(p + MST_BPDU_VER3_LEN_OFFSET);
 333             mstp_len += 2;  /* length encoding itself is 2 bytes */
 334             if (length < (sizeof(struct stp_bpdu_) + mstp_len)) {
 335                 goto trunc;
 336             }
 337             stp_print_mstp_bpdu(stp_bpdu, length);
 338         }
 339         break;
 340
 341     case STP_BPDU_TYPE_TOPO_CHANGE:
 342         /* always empty message - just break out */
 343         break;
 344
 345     default:
 346         break;
 347     }
 348
 349     return;
 350  trunc:
 351     printf("[|stp %d]", length);
 352 }
 353
 354 /*
 355  * Local Variables:
 356  * c-style: whitesmith
 357  * c-basic-offset: 4
 358  * End:
 359  */