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 1.11.2.2 2003-11-16 08:51:46 guy 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 static void
  32 stp_print_bridge_id(const u_char *p)
  33 {
  34         printf("%.2x%.2x.%.2x:%.2x:%.2x:%.2x:%.2x:%.2x",
  35                p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]);
  36 }
  37
  38 static void
  39 stp_print_config_bpdu(const u_char *p)
  40 {
  41         printf("config ");
  42         if (p[7] & 1)
  43                 printf("TOP_CHANGE ");
  44         if (p[7] & 0x80)
  45                 printf("TOP_CHANGE_ACK ");
  46
  47         stp_print_bridge_id(p+20);
  48         printf(".%.2x%.2x ", p[28], p[29]);
  49
  50         printf("root ");
  51         stp_print_bridge_id(p+8);
  52
  53         printf(" pathcost %i ", (p[16] << 24) | (p[17] << 16) | (p[18] << 8) | p[19]);
  54
  55         printf("age %i ", p[30]);
  56         printf("max %i ", p[32]);
  57         printf("hello %i ", p[34]);
  58         printf("fdelay %i ", p[36]);
  59 }
  60
  61 static void
  62 stp_print_tcn_bpdu(void)
  63 {
  64         printf("tcn");
  65 }
  66
  67 /*
  68  * Print 802.1d packets.
  69  */
  70 void
  71 stp_print(const u_char *p, u_int length)
  72 {
  73         if (length < 7)
  74                 goto trunc;
  75
  76         printf("802.1d ");
  77         if (p[2] != 0x03 || p[3] || p[4] || p[5]) {
  78                 printf("unknown version");
  79                 return;
  80         }
  81
  82         switch (p[6])
  83         {
  84         case 0x00:
  85                 if (length < 10)
  86                         goto trunc;
  87                 stp_print_config_bpdu(p);
  88                 break;
  89
  90         case 0x80:
  91                 stp_print_tcn_bpdu();
  92                 break;
  93
  94         default:
  95                 printf("unknown type %i", p[6]);
  96                 break;
  97         }
  98
  99         return;
 100 trunc:
 101         printf("[|stp %d]", length);
 102 }