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 1.13.2.2 2007-03-06 15:07:05 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
  35 struct stp_bpdu_ {
  36     u_int8_t protocol_id[2];
  37     u_int8_t protocol_version;
  38     u_int8_t bpdu_type;
  39     u_int8_t flags;
  40     u_int8_t root_id[8];
  41     u_int8_t root_path_cost[4];
  42     u_int8_t bridge_id[8];
  43     u_int8_t port_id[2];
  44     u_int8_t message_age[2];
  45     u_int8_t max_age[2];
  46     u_int8_t hello_time[2];
  47     u_int8_t forward_delay[2];
  48     u_int8_t v1_length;
  49 };
  50
  51 #define STP_PROTO_REGULAR 0x00
  52 #define STP_PROTO_RAPID   0x02
  53
  54 struct tok stp_proto_values[] = {
  55     { STP_PROTO_REGULAR, "802.1d" },
  56     { STP_PROTO_RAPID, "802.1w" },
  57     { 0, NULL}
  58 };
  59
  60 #define STP_BPDU_TYPE_CONFIG      0x00
  61 #define STP_BPDU_TYPE_RSTP        0x02
  62 #define STP_BPDU_TYPE_TOPO_CHANGE 0x80
  63
  64 struct tok stp_bpdu_flag_values[] = {
  65     { 0x01, "Topology change" },
  66     { 0x02, "Proposal" },
  67     { 0x10, "Learn" },
  68     { 0x20, "Forward" },
  69     { 0x40, "Agreement" },
  70     { 0x80, "Topology change ACK" },
  71     { 0, NULL}
  72 };
  73
  74 struct tok stp_bpdu_type_values[] = {
  75     { STP_BPDU_TYPE_CONFIG, "Config" },
  76     { STP_BPDU_TYPE_RSTP, "Rapid SPT" },
  77     { STP_BPDU_TYPE_TOPO_CHANGE, "Topology Change" },
  78     { 0, NULL}
  79 };
  80
  81 struct tok rstp_obj_port_role_values[] = {
  82     { 0x00, "Unknown" },
  83     { 0x01, "Alternate" },
  84     { 0x02, "Root" },
  85     { 0x03, "Designated" },
  86     { 0, NULL}
  87 };
  88
  89 static char *
  90 stp_print_bridge_id(const u_char *p)
  91 {
  92     static char bridge_id_str[sizeof("pppp.aa:bb:cc:dd:ee:ff")];
  93
  94     snprintf(bridge_id_str, sizeof(bridge_id_str),
  95              "%.2x%.2x.%.2x:%.2x:%.2x:%.2x:%.2x:%.2x",
  96              p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]);
  97
  98     return bridge_id_str;
  99 }
 100
 101 static void
 102 stp_print_config_bpdu(const struct stp_bpdu_ *stp_bpdu, u_int length)
 103 {
 104     printf(", Flags [%s]",
 105            bittok2str(stp_bpdu_flag_values, "none", stp_bpdu->flags));
 106
 107     printf(", bridge-id %s.%04x, length %u",
 108            stp_print_bridge_id((const u_char *)&stp_bpdu->bridge_id),
 109            EXTRACT_16BITS(&stp_bpdu->port_id), length);
 110
 111     /* in non-verbose mode just print the bridge-id */
 112     if (!vflag) {
 113         return;
 114     }
 115
 116     printf("\n\tmessage-age %.2fs, max-age %.2fs"
 117            ", hello-time %.2fs, forwarding-delay %.2fs",
 118            (float)EXTRACT_16BITS(&stp_bpdu->message_age) / STP_TIME_BASE,
 119            (float)EXTRACT_16BITS(&stp_bpdu->max_age) / STP_TIME_BASE,
 120            (float)EXTRACT_16BITS(&stp_bpdu->hello_time) / STP_TIME_BASE,
 121            (float)EXTRACT_16BITS(&stp_bpdu->forward_delay) / STP_TIME_BASE);
 122
 123     printf("\n\troot-id %s, root-pathcost %u",
 124            stp_print_bridge_id((const u_char *)&stp_bpdu->root_id),
 125            EXTRACT_32BITS(&stp_bpdu->root_path_cost) / STP_TIME_BASE);
 126
 127     /* Port role is only valid for 802.1w */
 128     if (stp_bpdu->protocol_version == STP_PROTO_RAPID) {
 129         printf(", port-role %s",
 130                tok2str(rstp_obj_port_role_values, "Unknown",
 131                        RSTP_EXTRACT_PORT_ROLE(stp_bpdu->flags)));
 132     }
 133 }
 134
 135 /*
 136  * Print 802.1d / 802.1w packets.
 137  */
 138 void
 139 stp_print(const u_char *p, u_int length)
 140 {
 141     const struct stp_bpdu_ *stp_bpdu;
 142
 143     stp_bpdu = (struct stp_bpdu_*)p;
 144
 145     /* Minimum SPT Frame size. */
 146     if (length < 4)
 147         goto trunc;
 148
 149     if (EXTRACT_16BITS(&stp_bpdu->protocol_id)) {
 150         printf("unknown STP version, length %u", length);
 151         return;
 152     }
 153
 154     printf("STP %s", tok2str(stp_proto_values, "Unknown STP protocol (0x%02x)",
 155                          stp_bpdu->protocol_version));
 156
 157     switch (stp_bpdu->protocol_version) {
 158     case STP_PROTO_REGULAR:
 159     case STP_PROTO_RAPID:
 160         break;
 161     default:
 162         return;
 163     }
 164
 165     printf(", %s", tok2str(stp_bpdu_type_values, "Unknown BPDU Type (0x%02x)",
 166                            stp_bpdu->bpdu_type));
 167
 168     switch (stp_bpdu->bpdu_type) {
 169     case STP_BPDU_TYPE_CONFIG:
 170         if (length < sizeof(struct stp_bpdu_) - 1) {
 171             goto trunc;
 172         }
 173         stp_print_config_bpdu(stp_bpdu, length);
 174         break;
 175
 176     case STP_BPDU_TYPE_RSTP:
 177         if (length < sizeof(struct stp_bpdu_)) {
 178             goto trunc;
 179         }
 180         stp_print_config_bpdu(stp_bpdu, length);
 181         break;
 182
 183     case STP_BPDU_TYPE_TOPO_CHANGE:
 184         /* always empty message - just break out */
 185         break;
 186
 187     default:
 188         break;
 189     }
 190
 191     return;
 192  trunc:
 193     printf("[|stp %d]", length);
 194 }
 195
 196 /*
 197  * Local Variables:
 198  * c-style: whitesmith
 199  * c-basic-offset: 4
 200  * End:
 201  */