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 1.12 2000/12/02 08:41:07 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 <string.h>
  43 #include <glib.h>
  44 #include "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 };
  87
  88 #define HSRP_STATE_INITIAL  0
  89 #define HSRP_STATE_LEARN    1
  90 #define HSRP_STATE_LISTEN   2
  91 #define HSRP_STATE_SPEAK    4
  92 #define HSRP_STATE_STANDBY  8
  93 #define HSRP_STATE_ACTIVE  16
  94 static const value_string hsrp_state_vals[] = {
  95         {HSRP_STATE_INITIAL, "Initial"},
  96         {HSRP_STATE_LEARN,   "Learn"},
  97         {HSRP_STATE_LISTEN,  "Listen"},
  98         {HSRP_STATE_SPEAK,   "Speak"},
  99         {HSRP_STATE_STANDBY, "Standby"},
 100         {HSRP_STATE_ACTIVE,  "Active"}
 101 };
 102
 103 static void
 104 dissect_hsrp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 105 {
 106         guint8 opcode, state;
 107
 108         CHECK_DISPLAY_AS_DATA(proto_hsrp, tvb, pinfo, tree);
 109
 110         pinfo->current_proto = "HSRP";
 111
 112         if (check_col(pinfo->fd, COL_PROTOCOL))
 113                 col_set_str(pinfo->fd, COL_PROTOCOL, "HSRP");
 114
 115         opcode = tvb_get_guint8(tvb, 1);
 116         state = tvb_get_guint8(tvb, 2);
 117         if (check_col(pinfo->fd, COL_INFO)) {
 118                 col_add_fstr(pinfo->fd, 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                 guint32 virt_ip_addr;
 130
 131                 offset = 0;
 132                 ti = proto_tree_add_item(tree, proto_hsrp, tvb, offset, tvb_length(tvb), FALSE);
 133                 hsrp_tree = proto_item_add_subtree(ti, ett_hsrp);
 134
 135                 proto_tree_add_uint(hsrp_tree, hf_hsrp_version, tvb, offset, 1, tvb_get_guint8(tvb, offset));
 136                 offset++;
 137                 proto_tree_add_uint(hsrp_tree, hf_hsrp_opcode, tvb, offset, 1, opcode);
 138                 offset++;
 139                 proto_tree_add_uint(hsrp_tree, hf_hsrp_state, tvb, offset, 1, state);
 140                 offset++;
 141                 hellotime = tvb_get_guint8(tvb, offset);
 142                 proto_tree_add_uint_format(hsrp_tree, hf_hsrp_hellotime, tvb, offset, 1, hellotime,
 143                                            "Hellotime: %sDefault (%u)",
 144                                            (hellotime == HSRP_DEFAULT_HELLOTIME) ? "" : "Non-",
 145                                            hellotime);
 146                 offset++;
 147                 holdtime = tvb_get_guint8(tvb, offset);
 148                 proto_tree_add_uint_format(hsrp_tree, hf_hsrp_holdtime, tvb, offset, 1, holdtime,
 149                                            "Holdtime: %sDefault (%u)",
 150                                            (holdtime == HSRP_DEFAULT_HOLDTIME) ? "" : "Non-",
 151                                            holdtime);
 152                 offset++;
 153                 proto_tree_add_item(hsrp_tree, hf_hsrp_priority, tvb, offset, 1, tvb_get_guint8(tvb, offset));
 154                 offset++;
 155                 proto_tree_add_item(hsrp_tree, hf_hsrp_group, tvb, offset, 1, tvb_get_guint8(tvb, offset));
 156                 offset++;
 157                 proto_tree_add_item(hsrp_tree, hf_hsrp_reserved, tvb, offset, 1, tvb_get_guint8(tvb, offset));
 158                 offset++;
 159                 tvb_memcpy(tvb, auth_buf, offset, 8);
 160                 auth_buf[sizeof auth_buf - 1] = '\0';
 161                 proto_tree_add_string_format(hsrp_tree, hf_hsrp_auth_data, tvb, offset, 8, auth_buf,
 162                                              "Authentication Data: %sDefault (%s)",
 163                                              (tvb_strneql(tvb, offset, "cisco", strlen("cisco"))) == 0 ? "" : "Non-",
 164                                              auth_buf);
 165                 offset += 8;
 166                 tvb_memcpy(tvb, (guint8 *)&virt_ip_addr, offset, 4);
 167                 proto_tree_add_ipv4(hsrp_tree, hf_hsrp_virt_ip_addr, tvb, offset, 4, virt_ip_addr);
 168                 offset += 4;
 169
 170         }
 171
 172         return;
 173 }
 174
 175 void proto_register_hsrp(void)
 176 {
 177         static hf_register_info hf[] = {
 178                 { &hf_hsrp_version,
 179                   { "Version", "hsrp.version",
 180                     FT_UINT8, BASE_DEC, NULL, 0x0,
 181                     "The version of the HSRP messages"}},
 182
 183                 { &hf_hsrp_opcode,
 184                   { "Op Code", "hsrp.opcode",
 185                     FT_UINT8, BASE_DEC, VALS(hsrp_opcode_vals), 0x0,
 186                     "The type of message contained in this packet" }},
 187
 188                 { &hf_hsrp_state,
 189                   { "State", "hsrp.state",
 190                     FT_UINT8, BASE_DEC, VALS(hsrp_state_vals), 0x0,
 191                     "The current state of the router sending the message" }},
 192
 193                 { &hf_hsrp_hellotime,
 194                   { "Hellotime", "hsrp.hellotime",
 195                     FT_UINT8, BASE_DEC, NULL, 0x0,
 196                     "The approximate period between the Hello messages that the router sends" }},
 197
 198                 { &hf_hsrp_holdtime,
 199                   { "Holdtime", "hsrp.holdtime",
 200                     FT_UINT8, BASE_DEC, NULL, 0x0,
 201                     "Time that the current Hello message should be considered valid" }},
 202
 203                 { &hf_hsrp_priority,
 204                   { "Priority", "hsrp.priority",
 205                     FT_UINT8, BASE_DEC, NULL, 0x0,
 206                     "Used to elect the active and standby routers. Numerically higher priority wins vote" }},
 207
 208                 { &hf_hsrp_group,
 209                   { "Group", "hsrp.group",
 210                     FT_UINT8, BASE_DEC, NULL, 0x0,
 211                     "This field identifies the standby group" }},
 212
 213                 { &hf_hsrp_reserved,
 214                   { "Reserved", "hsrp.reserved",
 215                     FT_UINT8, BASE_DEC, NULL, 0x0,
 216                     "Reserved" }},
 217
 218                 { &hf_hsrp_auth_data,
 219                   { "Authentication Data", "hsrp.auth_data",
 220                     FT_STRING, 0, NULL, 0x0,
 221                     "Contains a clear-text 8 character reused password" }},
 222
 223                 { &hf_hsrp_virt_ip_addr,
 224                   { "Virtual IP Address", "hsrp.virt_ip",
 225                     FT_IPv4, 0, NULL, 0x0,
 226                     "The virtual IP address used by this group" }},
 227
 228         };
 229
 230         static gint *ett[] = {
 231                 &ett_hsrp,
 232         };
 233
 234         proto_hsrp = proto_register_protocol("Cisco Hot Standby Router Protocol", "hsrp");
 235         proto_register_field_array(proto_hsrp, hf, array_length(hf));
 236         proto_register_subtree_array(ett, array_length(ett));
 237
 238         return;
 239 }
 240
 241 void
 242 proto_reg_handoff_hsrp(void)
 243 {
 244         dissector_add("udp.port", UDP_PORT_HSRP, dissect_hsrp);
 245 }