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 1.4 2000/05/11 08:15:10 gram 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 #define UDP_PORT_HSRP   1985
  49
  50 struct hsrp_packet {          /* Multicast to 224.0.0.2, TTL 1, UDP, port 1985 */
  51         guint8  version;      /* RFC2281 describes version 0 */
  52         guint8  opcode;
  53         guint8  state;
  54 #define HSRP_DEFAULT_HELLOTIME 3
  55         guint8  hellotime;    /* In seconds */
  56 #define HSRP_DEFAULT_HOLDTIME 10
  57         guint8  holdtime;     /* In seconds */
  58         guint8  priority;     /* Higher is stronger, highest IP address tie-breaker */
  59         guint8  group;        /* Identifies the standby group */
  60         guint8  reserved;
  61         guint8  auth_data[8]; /* Clear-text password, recommended default is `cisco' */
  62         guint32 virt_ip_addr; /* The virtual IP address used by this group */
  63 };
  64
  65
  66 #define HSRP_OPCODE_HELLO  0
  67 #define HSRP_OPCODE_COUP   1
  68 #define HSRP_OPCODE_RESIGN 2
  69 static const value_string hsrp_opcode_vals[] = {
  70         {HSRP_OPCODE_HELLO,  "Hello"},
  71         {HSRP_OPCODE_COUP,   "Coup"},
  72         {HSRP_OPCODE_RESIGN, "Resign"}
  73 };
  74
  75 #define HSRP_STATE_INITIAL  0
  76 #define HSRP_STATE_LEARN    1
  77 #define HSRP_STATE_LISTEN   2
  78 #define HSRP_STATE_SPEAK    4
  79 #define HSRP_STATE_STANDBY  8
  80 #define HSRP_STATE_ACTIVE  16
  81 static const value_string hsrp_state_vals[] = {
  82         {HSRP_STATE_INITIAL, "Initial"},
  83         {HSRP_STATE_LEARN,   "Learn"},
  84         {HSRP_STATE_LISTEN,  "Listen"},
  85         {HSRP_STATE_SPEAK,   "Speak"},
  86         {HSRP_STATE_STANDBY, "Standby"},
  87         {HSRP_STATE_ACTIVE,  "Active"}
  88 };
  89
  90 static void
  91 dissect_hsrp(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
  92 {
  93         struct hsrp_packet hsrp;
  94         gboolean short_packet = FALSE;
  95
  96         if (sizeof(struct hsrp_packet) > END_OF_FRAME)
  97                 short_packet = TRUE;
  98         else
  99                 memcpy(&hsrp, pd + offset, sizeof(struct hsrp_packet));
 100
 101         if (check_col(fd, COL_PROTOCOL))
 102                 col_add_str(fd, COL_PROTOCOL, "HSRP");
 103
 104         if (check_col(fd, COL_INFO)) {
 105                 if (short_packet)
 106                         col_add_fstr(fd, COL_INFO, "Short packet, length %u", END_OF_FRAME);
 107                 else
 108                         col_add_fstr(fd, COL_INFO, "%s (state %s)",
 109                                      val_to_str(hsrp.opcode, hsrp_opcode_vals, "Unknown"),
 110                                      val_to_str(hsrp.state, hsrp_state_vals, "Unknown"));
 111         }
 112
 113         if (tree) {
 114                 proto_item *ti;
 115                 proto_tree *hsrp_tree;
 116                 guint8 auth_buf[sizeof(hsrp.auth_data) + 1];
 117
 118                 if (short_packet) {
 119                         dissect_data(pd, offset, fd, tree);
 120                         return;
 121                 }
 122
 123                 ti = proto_tree_add_item(tree, proto_hsrp, NullTVB, offset, END_OF_FRAME, NULL);
 124                 hsrp_tree = proto_item_add_subtree(ti, ett_hsrp);
 125
 126                 proto_tree_add_text(hsrp_tree, NullTVB, offset++, 1, "Version: %u", hsrp.version);
 127                 proto_tree_add_text(hsrp_tree, NullTVB, offset++, 1, "Opcode: %u (%s)", hsrp.opcode,
 128                                     val_to_str(hsrp.opcode, hsrp_opcode_vals, "Unknown"));
 129                 proto_tree_add_text(hsrp_tree, NullTVB, offset++, 1, "State: %u (%s)", hsrp.state,
 130                                     val_to_str(hsrp.state, hsrp_state_vals, "Unknown"));
 131
 132                 proto_tree_add_text(hsrp_tree, NullTVB, offset++, 1, "Hellotime: %u second%s (%sdefault)",
 133                                     hsrp.hellotime, plurality(hsrp.hellotime, "", "s"),
 134                                     (hsrp.hellotime == HSRP_DEFAULT_HELLOTIME) ? "" : "non-");
 135                 proto_tree_add_text(hsrp_tree, NullTVB, offset++, 1, "Holdtime: %u second%s (%sdefault)",
 136                                     hsrp.holdtime, plurality(hsrp.holdtime, "", "s"),
 137                                     (hsrp.holdtime == HSRP_DEFAULT_HOLDTIME) ? "" : "non-");
 138                 proto_tree_add_text(hsrp_tree, NullTVB, offset++, 1, "Priority: %u", hsrp.priority);
 139                 proto_tree_add_text(hsrp_tree, NullTVB, offset++, 1, "Group: %u", hsrp.group);
 140                 proto_tree_add_text(hsrp_tree, NullTVB, offset++, 1, "Reserved: 0x%x", hsrp.reserved);
 141
 142                 memcpy(auth_buf, hsrp.auth_data, sizeof(hsrp.auth_data));
 143                 auth_buf[sizeof(auth_buf)] = '\0';
 144                 proto_tree_add_text(hsrp_tree, NullTVB, offset, 8, "Authentication Data: `%s'", auth_buf);
 145                 offset+=8;
 146
 147                 proto_tree_add_text(hsrp_tree, NullTVB, offset++, 4, "Virtual IP address: %s",
 148                                     ip_to_str((guint8 *)&hsrp.virt_ip_addr));
 149
 150         }
 151
 152         return;
 153 }
 154
 155 void proto_register_hsrp(void)
 156 {
 157         static gint *ett[] = {
 158                 &ett_hsrp,
 159         };
 160
 161         proto_hsrp = proto_register_protocol("Cisco Hot Standby Router Protocol", "hsrp");
 162         proto_register_subtree_array(ett, array_length(ett));
 163
 164         return;
 165 }
 166
 167 void
 168 proto_reg_handoff_hsrp(void)
 169 {
 170         dissector_add("udp.port", UDP_PORT_HSRP, dissect_hsrp);
 171 }