packet-hsrp.c

   1 /* packet-hsrp.c
   2  * Routines for the Cisco Hot Standby Router Protocol (HSRP)
   3  * RFC2281
   4  *
   5  * Heikki Vatiainen <hessu@cs.tut.fi>
   6  *
   7  * $Id: packet-hsrp.c,v 1.2 2000/01/07 22:05:31 guy Exp $
   8  *
   9  * Ethereal - Network traffic analyzer
  10  * By Gerald Combs <gerald@zing.org>
  11  * Copyright 1998 Gerald Combs
  12  *
  13  * Copied from packet-vrrp.c
  14  *
  15  * This program is free software; you can redistribute it and/or
  16  * modify it under the terms of the GNU General Public License
  17  * as published by the Free Software Foundation; either version 2
  18  * of the License, or (at your option) any later version.
  19  *
  20  * This program is distributed in the hope that it will be useful,
  21  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  22  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23  * GNU General Public License for more details.
  24  *
  25  * You should have received a copy of the GNU General Public License
  26  * along with this program; if not, write to the Free Software
  27  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  28  */
  29
  30 #ifdef HAVE_CONFIG_H
  31 # include "config.h"
  32 #endif
  33
  34 #ifdef HAVE_SYS_TYPES_H
  35 # include <sys/types.h>
  36 #endif
  37
  38 #ifdef HAVE_NETINET_IN_H
  39 #include <netinet/in.h>
  40 #endif
  41
  42 #include <glib.h>
  43 #include "packet.h"
  44
  45 static gint proto_hsrp = -1;
  46 static gint ett_hsrp = -1;
  47
  48 struct hsrp_packet {          /* Multicast to 224.0.0.2, TTL 1, UDP, port 1985 */
  49         guint8  version;      /* RFC2281 describes version 0 */
  50         guint8  opcode;
  51         guint8  state;
  52 #define HSRP_DEFAULT_HELLOTIME 3
  53         guint8  hellotime;    /* In seconds */
  54 #define HSRP_DEFAULT_HOLDTIME 10
  55         guint8  holdtime;     /* In seconds */
  56         guint8  priority;     /* Higher is stronger, highest IP address tie-breaker */
  57         guint8  group;        /* Identifies the standby group */
  58         guint8  reserved;
  59         guint8  auth_data[8]; /* Clear-text password, recommended default is `cisco' */
  60         guint32 virt_ip_addr; /* The virtual IP address used by this group */
  61 };
  62
  63
  64 #define HSRP_OPCODE_HELLO  0
  65 #define HSRP_OPCODE_COUP   1
  66 #define HSRP_OPCODE_RESIGN 2
  67 static const value_string hsrp_opcode_vals[] = {
  68         {HSRP_OPCODE_HELLO,  "Hello"},
  69         {HSRP_OPCODE_COUP,   "Coup"},
  70         {HSRP_OPCODE_RESIGN, "Resign"}
  71 };
  72
  73 #define HSRP_STATE_INITIAL  0
  74 #define HSRP_STATE_LEARN    1
  75 #define HSRP_STATE_LISTEN   2
  76 #define HSRP_STATE_SPEAK    4
  77 #define HSRP_STATE_STANDBY  8
  78 #define HSRP_STATE_ACTIVE  16
  79 static const value_string hsrp_state_vals[] = {
  80         {HSRP_STATE_INITIAL, "Initial"},
  81         {HSRP_STATE_LEARN,   "Learn"},
  82         {HSRP_STATE_LISTEN,  "Listen"},
  83         {HSRP_STATE_SPEAK,   "Speak"},
  84         {HSRP_STATE_STANDBY, "Standby"},
  85         {HSRP_STATE_ACTIVE,  "Active"}
  86 };
  87
  88 void dissect_hsrp(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
  89 {
  90         struct hsrp_packet hsrp;
  91         gboolean short_packet = FALSE;
  92
  93         if (sizeof(struct hsrp_packet) > END_OF_FRAME)
  94                 short_packet = TRUE;
  95         else
  96                 memcpy(&hsrp, pd + offset, sizeof(struct hsrp_packet));
  97
  98         if (check_col(fd, COL_PROTOCOL))
  99                 col_add_str(fd, COL_PROTOCOL, "HSRP");
 100
 101         if (check_col(fd, COL_INFO)) {
 102                 if (short_packet)
 103                         col_add_fstr(fd, COL_INFO, "Short packet, length %u", END_OF_FRAME);
 104                 else
 105                         col_add_fstr(fd, COL_INFO, "%s (state %s)",
 106                                      val_to_str(hsrp.opcode, hsrp_opcode_vals, "Unknown"),
 107                                      val_to_str(hsrp.state, hsrp_state_vals, "Unknown"));
 108         }
 109
 110         if (tree) {
 111                 proto_item *ti;
 112                 proto_tree *hsrp_tree;
 113                 guint8 auth_buf[sizeof(hsrp.auth_data) + 1];
 114
 115                 if (short_packet) {
 116                         dissect_data(pd, offset, fd, tree);
 117                         return;
 118                 }
 119
 120                 ti = proto_tree_add_item(tree, proto_hsrp, offset, END_OF_FRAME, NULL);
 121                 hsrp_tree = proto_item_add_subtree(ti, ett_hsrp);
 122
 123                 proto_tree_add_text(hsrp_tree, offset++, 1, "Version: %u", hsrp.version);
 124                 proto_tree_add_text(hsrp_tree, offset++, 1, "Opcode: %u (%s)", hsrp.opcode,
 125                                     val_to_str(hsrp.opcode, hsrp_opcode_vals, "Unknown"));
 126                 proto_tree_add_text(hsrp_tree, offset++, 1, "State: %u (%s)", hsrp.state,
 127                                     val_to_str(hsrp.state, hsrp_state_vals, "Unknown"));
 128
 129                 proto_tree_add_text(hsrp_tree, offset++, 1, "Hellotime: %u second%s (%sdefault)",
 130                                     hsrp.hellotime, plurality(hsrp.hellotime, "", "s"),
 131                                     (hsrp.hellotime == HSRP_DEFAULT_HELLOTIME) ? "" : "non-");
 132                 proto_tree_add_text(hsrp_tree, offset++, 1, "Holdtime: %u second%s (%sdefault)",
 133                                     hsrp.holdtime, plurality(hsrp.holdtime, "", "s"),
 134                                     (hsrp.holdtime == HSRP_DEFAULT_HOLDTIME) ? "" : "non-");
 135                 proto_tree_add_text(hsrp_tree, offset++, 1, "Priority: %u", hsrp.priority);
 136                 proto_tree_add_text(hsrp_tree, offset++, 1, "Group: %u", hsrp.group);
 137                 proto_tree_add_text(hsrp_tree, offset++, 1, "Reserved: 0x%x", hsrp.reserved);
 138
 139                 memcpy(auth_buf, hsrp.auth_data, sizeof(hsrp.auth_data));
 140                 auth_buf[sizeof(auth_buf)] = '\0';
 141                 proto_tree_add_text(hsrp_tree, offset, 8, "Authentication Data: `%s'", auth_buf);
 142                 offset+=8;
 143
 144                 proto_tree_add_text(hsrp_tree, offset++, 4, "Virtual IP address: %s",
 145                                     ip_to_str((guint8 *)&hsrp.virt_ip_addr));
 146
 147         }
 148
 149         return;
 150 }
 151
 152 void proto_register_hsrp(void)
 153 {
 154         static gint *ett[] = {
 155                 &ett_hsrp,
 156         };
 157
 158         proto_hsrp = proto_register_protocol("Cisco Hot Standby Router Protocol", "hsrp");
 159         proto_register_subtree_array(ett, array_length(ett));
 160
 161         return;
 162 }