packet-hsrp.c

   1 /* packet-hsrp.c
   2  * Routines for the Cisco Hot Standby Router Protocol (HSRP)
   3  * RFC 2281
   4  *
   5  * Heikki Vatiainen <hessu@cs.tut.fi>
   6  *
   7  * $Id: packet-hsrp.c,v 1.22 2002/01/24 09:20:48 guy Exp $
   8  *
   9  * Ethereal - Network traffic analyzer
  10  * By Gerald Combs <gerald@ethereal.com>
  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 <string.h>
  43 #include <glib.h>
  44 #include <epan/packet.h>
  45
  46 static gint proto_hsrp = -1;
  47
  48 static gint hf_hsrp_version = -1;
  49 static gint hf_hsrp_opcode = -1;
  50 static gint hf_hsrp_state = -1;
  51 static gint hf_hsrp_hellotime = -1;
  52 static gint hf_hsrp_holdtime = -1;
  53 static gint hf_hsrp_priority = -1;
  54 static gint hf_hsrp_group = -1;
  55 static gint hf_hsrp_reserved = -1;
  56 static gint hf_hsrp_auth_data = -1;
  57 static gint hf_hsrp_virt_ip_addr = -1;
  58
  59 static gint ett_hsrp = -1;
  60
  61 #define UDP_PORT_HSRP   1985
  62
  63 struct hsrp_packet {          /* Multicast to 224.0.0.2, TTL 1, UDP, port 1985 */
  64         guint8  version;      /* RFC2281 describes version 0 */
  65         guint8  opcode;
  66         guint8  state;
  67 #define HSRP_DEFAULT_HELLOTIME 3
  68         guint8  hellotime;    /* In seconds */
  69 #define HSRP_DEFAULT_HOLDTIME 10
  70         guint8  holdtime;     /* In seconds */
  71         guint8  priority;     /* Higher is stronger, highest IP address tie-breaker */
  72         guint8  group;        /* Identifies the standby group */
  73         guint8  reserved;
  74         guint8  auth_data[8]; /* Clear-text password, recommended default is `cisco' */
  75         guint32 virt_ip_addr; /* The virtual IP address used by this group */
  76 };
  77
  78
  79 #define HSRP_OPCODE_HELLO  0
  80 #define HSRP_OPCODE_COUP   1
  81 #define HSRP_OPCODE_RESIGN 2
  82 static const value_string hsrp_opcode_vals[] = {
  83         {HSRP_OPCODE_HELLO,  "Hello"},
  84         {HSRP_OPCODE_COUP,   "Coup"},
  85         {HSRP_OPCODE_RESIGN, "Resign"},
  86         {0, NULL},
  87 };
  88
  89 #define HSRP_STATE_INITIAL  0
  90 #define HSRP_STATE_LEARN    1
  91 #define HSRP_STATE_LISTEN   2
  92 #define HSRP_STATE_SPEAK    4
  93 #define HSRP_STATE_STANDBY  8
  94 #define HSRP_STATE_ACTIVE  16
  95 static const value_string hsrp_state_vals[] = {
  96         {HSRP_STATE_INITIAL, "Initial"},
  97         {HSRP_STATE_LEARN,   "Learn"},
  98         {HSRP_STATE_LISTEN,  "Listen"},
  99         {HSRP_STATE_SPEAK,   "Speak"},
 100         {HSRP_STATE_STANDBY, "Standby"},
 101         {HSRP_STATE_ACTIVE,  "Active"},
 102         {0, NULL},
 103 };
 104
 105 static void
 106 dissect_hsrp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 107 {
 108         guint8 opcode, state;
 109
 110         if (check_col(pinfo->cinfo, COL_PROTOCOL))
 111                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "HSRP");
 112         if (check_col(pinfo->cinfo, COL_INFO))
 113                 col_clear(pinfo->cinfo, COL_INFO);
 114
 115         opcode = tvb_get_guint8(tvb, 1);
 116         state = tvb_get_guint8(tvb, 2);
 117         if (check_col(pinfo->cinfo, COL_INFO)) {
 118                 col_add_fstr(pinfo->cinfo, COL_INFO, "%s (state %s)",
 119                              val_to_str(opcode, hsrp_opcode_vals, "Unknown"),
 120                              val_to_str(state, hsrp_state_vals, "Unknown"));
 121         }
 122
 123         if (tree) {
 124                 proto_item *ti;
 125                 proto_tree *hsrp_tree;
 126                 int offset;
 127                 guint8 hellotime, holdtime;
 128                 guint8 auth_buf[8 + 1];
 129
 130                 offset = 0;
 131                 ti = proto_tree_add_item(tree, proto_hsrp, tvb, offset, -1, FALSE);
 132                 hsrp_tree = proto_item_add_subtree(ti, ett_hsrp);
 133
 134                 proto_tree_add_item(hsrp_tree, hf_hsrp_version, tvb, offset, 1, FALSE);
 135                 offset++;
 136                 proto_tree_add_uint(hsrp_tree, hf_hsrp_opcode, tvb, offset, 1, opcode);
 137                 offset++;
 138                 proto_tree_add_uint(hsrp_tree, hf_hsrp_state, tvb, offset, 1, state);
 139                 offset++;
 140                 hellotime = tvb_get_guint8(tvb, offset);
 141                 proto_tree_add_uint_format(hsrp_tree, hf_hsrp_hellotime, tvb, offset, 1, hellotime,
 142                                            "Hellotime: %sDefault (%u)",
 143                                            (hellotime == HSRP_DEFAULT_HELLOTIME) ? "" : "Non-",
 144                                            hellotime);
 145                 offset++;
 146                 holdtime = tvb_get_guint8(tvb, offset);
 147                 proto_tree_add_uint_format(hsrp_tree, hf_hsrp_holdtime, tvb, offset, 1, holdtime,
 148                                            "Holdtime: %sDefault (%u)",
 149                                            (holdtime == HSRP_DEFAULT_HOLDTIME) ? "" : "Non-",
 150                                            holdtime);
 151                 offset++;
 152                 proto_tree_add_item(hsrp_tree, hf_hsrp_priority, tvb, offset, 1, FALSE);
 153                 offset++;
 154                 proto_tree_add_item(hsrp_tree, hf_hsrp_group, tvb, offset, 1, FALSE);
 155                 offset++;
 156                 proto_tree_add_item(hsrp_tree, hf_hsrp_reserved, tvb, offset, 1, FALSE);
 157                 offset++;
 158                 tvb_memcpy(tvb, auth_buf, offset, 8);
 159                 auth_buf[sizeof auth_buf - 1] = '\0';
 160                 proto_tree_add_string_format(hsrp_tree, hf_hsrp_auth_data, tvb, offset, 8, auth_buf,
 161                                              "Authentication Data: %sDefault (%s)",
 162                                              (tvb_strneql(tvb, offset, "cisco", strlen("cisco"))) == 0 ? "" : "Non-",
 163                                              auth_buf);
 164                 offset += 8;
 165                 proto_tree_add_item(hsrp_tree, hf_hsrp_virt_ip_addr, tvb, offset, 4, FALSE);
 166                 offset += 4;
 167
 168         }
 169
 170         return;
 171 }
 172
 173 void proto_register_hsrp(void)
 174 {
 175         static hf_register_info hf[] = {
 176                 { &hf_hsrp_version,
 177                   { "Version", "hsrp.version",
 178                     FT_UINT8, BASE_DEC, NULL, 0x0,
 179                     "The version of the HSRP messages", HFILL }},
 180
 181                 { &hf_hsrp_opcode,
 182                   { "Op Code", "hsrp.opcode",
 183                     FT_UINT8, BASE_DEC, VALS(hsrp_opcode_vals), 0x0,
 184                     "The type of message contained in this packet", HFILL }},
 185
 186                 { &hf_hsrp_state,
 187                   { "State", "hsrp.state",
 188                     FT_UINT8, BASE_DEC, VALS(hsrp_state_vals), 0x0,
 189                     "The current state of the router sending the message", HFILL }},
 190
 191                 { &hf_hsrp_hellotime,
 192                   { "Hellotime", "hsrp.hellotime",
 193                     FT_UINT8, BASE_DEC, NULL, 0x0,
 194                     "The approximate period between the Hello messages that the router sends", HFILL }},
 195
 196                 { &hf_hsrp_holdtime,
 197                   { "Holdtime", "hsrp.holdtime",
 198                     FT_UINT8, BASE_DEC, NULL, 0x0,
 199                     "Time that the current Hello message should be considered valid", HFILL }},
 200
 201                 { &hf_hsrp_priority,
 202                   { "Priority", "hsrp.priority",
 203                     FT_UINT8, BASE_DEC, NULL, 0x0,
 204                     "Used to elect the active and standby routers. Numerically higher priority wins vote", HFILL }},
 205
 206                 { &hf_hsrp_group,
 207                   { "Group", "hsrp.group",
 208                     FT_UINT8, BASE_DEC, NULL, 0x0,
 209                     "This field identifies the standby group", HFILL }},
 210
 211                 { &hf_hsrp_reserved,
 212                   { "Reserved", "hsrp.reserved",
 213                     FT_UINT8, BASE_DEC, NULL, 0x0,
 214                     "Reserved", HFILL }},
 215
 216                 { &hf_hsrp_auth_data,
 217                   { "Authentication Data", "hsrp.auth_data",
 218                     FT_STRING, 0, NULL, 0x0,
 219                     "Contains a clear-text 8 character reused password", HFILL }},
 220
 221                 { &hf_hsrp_virt_ip_addr,
 222                   { "Virtual IP Address", "hsrp.virt_ip",
 223                     FT_IPv4, 0, NULL, 0x0,
 224                     "The virtual IP address used by this group", HFILL }},
 225
 226         };
 227
 228         static gint *ett[] = {
 229                 &ett_hsrp,
 230         };
 231
 232         proto_hsrp = proto_register_protocol("Cisco Hot Standby Router Protocol",
 233             "HSRP", "hsrp");
 234         proto_register_field_array(proto_hsrp, hf, array_length(hf));
 235         proto_register_subtree_array(ett, array_length(ett));
 236
 237         return;
 238 }
 239
 240 void
 241 proto_reg_handoff_hsrp(void)
 242 {
 243         dissector_handle_t hsrp_handle;
 244
 245         hsrp_handle = create_dissector_handle(dissect_hsrp, proto_hsrp);
 246         dissector_add("udp.port", UDP_PORT_HSRP, hsrp_handle);
 247 }