packet-vrrp.c

   1 /* packet-vrrp.c
   2  * Routines for the Virtual Router Redundancy Protocol (VRRP)
   3  * RFC2338
   4  *
   5  * Heikki Vatiainen <hessu@cs.tut.fi>
   6  *
   7  * $Id: packet-vrrp.c,v 1.27 2003/06/12 06:58:38 guy Exp $
   8  *
   9  * Ethereal - Network traffic analyzer
  10  * By Gerald Combs <gerald@ethereal.com>
  11  * Copyright 1998 Gerald Combs
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License
  15  * as published by the Free Software Foundation; either version 2
  16  * of the License, or (at your option) any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program; if not, write to the Free Software
  25  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  26  */
  27
  28 #ifdef HAVE_CONFIG_H
  29 # include "config.h"
  30 #endif
  31
  32 #include <string.h>
  33 #include <glib.h>
  34 #include <epan/packet.h>
  35 #include "ipproto.h"
  36 #include "in_cksum.h"
  37
  38 static gint proto_vrrp = -1;
  39 static gint ett_vrrp = -1;
  40 static gint ett_vrrp_ver_type = -1;
  41
  42 static gint hf_vrrp_ver_type = -1;
  43 static gint hf_vrrp_version = -1;
  44 static gint hf_vrrp_type = -1;
  45 static gint hf_vrrp_virt_rtr_id = -1;
  46 static gint hf_vrrp_prio = -1;
  47 static gint hf_vrrp_count_ip = -1;
  48 static gint hf_vrrp_auth_type = -1;
  49 static gint hf_vrrp_adver_int = -1;
  50 static gint hf_vrrp_ip = -1;
  51 static gint hf_vrrp_ip6 = -1;
  52
  53 #define VRRP_VERSION_MASK 0xf0
  54 #define VRRP_TYPE_MASK 0x0f
  55 #define VRRP_AUTH_DATA_LEN 8
  56
  57 #define VRRP_TYPE_ADVERTISEMENT 1
  58 static const value_string vrrp_type_vals[] = {
  59         {VRRP_TYPE_ADVERTISEMENT, "Advertisement"},
  60         {0, NULL}
  61 };
  62
  63 #define VRRP_AUTH_TYPE_NONE 0
  64 #define VRRP_AUTH_TYPE_SIMPLE_TEXT 1
  65 #define VRRP_AUTH_TYPE_IP_AUTH_HDR 2
  66 static const value_string vrrp_auth_vals[] = {
  67         {VRRP_AUTH_TYPE_NONE,        "No Authentication"},
  68         {VRRP_AUTH_TYPE_SIMPLE_TEXT, "Simple Text Authentication"},
  69         {VRRP_AUTH_TYPE_IP_AUTH_HDR, "IP Authentication Header"},
  70         {0,                          NULL}
  71 };
  72
  73 #define VRRP_PRIORITY_MASTER_STOPPING 0
  74 /* Values between 1 and 254 inclusive are for backup VRRP routers */
  75 #define VRRP_PRIORITY_DEFAULT 100
  76 #define VRRP_PRIORITY_OWNER 255
  77 static const value_string vrrp_prio_vals[] = {
  78         {VRRP_PRIORITY_MASTER_STOPPING,  "Current Master has stopped participating in VRRP"},
  79         {VRRP_PRIORITY_DEFAULT,          "Default priority for a backup VRRP router"},
  80         {VRRP_PRIORITY_OWNER,            "This VRRP router owns the virtual router's IP address(es)"},
  81         {0,                              NULL }
  82 };
  83
  84
  85 static void
  86 dissect_vrrp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
  87 {
  88         int offset = 0;
  89         gint vrrp_len;
  90         guint8  ver_type;
  91         vec_t cksum_vec[4];
  92         guint32 phdr[2];
  93
  94         if (check_col(pinfo->cinfo, COL_PROTOCOL))
  95                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "VRRP");
  96         if (check_col(pinfo->cinfo, COL_INFO))
  97                 col_clear(pinfo->cinfo, COL_INFO);
  98
  99         ver_type = tvb_get_guint8(tvb, 0);
 100         if (check_col(pinfo->cinfo, COL_INFO)) {
 101                 col_add_fstr(pinfo->cinfo, COL_INFO, "%s (v%u)",
 102                              "Announcement", hi_nibble(ver_type));
 103         }
 104
 105         if (tree) {
 106                 proto_item *ti, *tv;
 107                 proto_tree *vrrp_tree, *ver_type_tree;
 108                 guint8 priority, ip_count = 0, auth_type;
 109                 guint16 cksum, computed_cksum;
 110                 guint8 auth_buf[VRRP_AUTH_DATA_LEN + 1];
 111
 112                 ti = proto_tree_add_item(tree, proto_vrrp, tvb, 0, -1, FALSE);
 113                 vrrp_tree = proto_item_add_subtree(ti, ett_vrrp);
 114
 115                 tv = proto_tree_add_uint_format(vrrp_tree, hf_vrrp_ver_type,
 116                                                 tvb, offset, 1, ver_type,
 117                                                 "Version %u, Packet type %u (%s)",
 118                                                 hi_nibble(ver_type), lo_nibble(ver_type),
 119                                                 val_to_str(lo_nibble(ver_type), vrrp_type_vals, "Unknown"));
 120                 ver_type_tree = proto_item_add_subtree(tv, ett_vrrp_ver_type);
 121                 proto_tree_add_uint(ver_type_tree, hf_vrrp_version, tvb,
 122                                     offset, 1, ver_type);
 123                 proto_tree_add_uint(ver_type_tree, hf_vrrp_type, tvb, offset, 1,
 124                                     ver_type);
 125                 offset++;
 126
 127                 proto_tree_add_item(vrrp_tree, hf_vrrp_virt_rtr_id, tvb, offset, 1, FALSE);
 128                 offset++;
 129
 130                 priority = tvb_get_guint8(tvb, offset);
 131                 proto_tree_add_uint_format(vrrp_tree, hf_vrrp_prio, tvb, offset, 1, priority, "Priority: %u (%s)",
 132                                            priority,
 133                                            val_to_str(priority, vrrp_prio_vals, "Non-default backup priority"));
 134                 offset++;
 135
 136                 switch(hi_nibble(ver_type)) {
 137                 case 3:
 138                         /* Skip reserve field */
 139                         offset++;
 140                         break;
 141                 case 2:
 142                 default:
 143                         ip_count = tvb_get_guint8(tvb, offset);
 144                         proto_tree_add_uint(vrrp_tree, hf_vrrp_count_ip, tvb,
 145                             offset, 1, ip_count);
 146                         offset++;
 147                         break;
 148                 }
 149
 150                 auth_type = tvb_get_guint8(tvb, offset);
 151                 proto_tree_add_item(vrrp_tree, hf_vrrp_auth_type, tvb, offset, 1, FALSE);
 152                 offset++;
 153
 154                 proto_tree_add_item(vrrp_tree, hf_vrrp_adver_int, tvb, offset, 1, FALSE);
 155                 offset++;
 156
 157                 cksum = tvb_get_ntohs(tvb, offset);
 158                 vrrp_len = (gint)tvb_reported_length(tvb);
 159                 if (!pinfo->fragmented && (gint)tvb_length(tvb) >= vrrp_len) {
 160                         /* The packet isn't part of a fragmented datagram
 161                            and isn't truncated, so we can checksum it. */
 162                         switch(hi_nibble(ver_type)) {
 163                         case 3:
 164                                 /* Set up the fields of the pseudo-header. */
 165                                 cksum_vec[0].ptr = pinfo->src.data;
 166                                 cksum_vec[0].len = pinfo->src.len;
 167                                 cksum_vec[1].ptr = pinfo->dst.data;
 168                                 cksum_vec[1].len = pinfo->dst.len;
 169                                 cksum_vec[2].ptr = (const guint8 *)&phdr;
 170                                 phdr[0] = g_htonl(vrrp_len);
 171                                 phdr[1] = g_htonl(IP_PROTO_VRRP);
 172                                 cksum_vec[2].len = 8;
 173                                 cksum_vec[3].ptr = tvb_get_ptr(tvb, 0, vrrp_len);
 174                                 cksum_vec[3].len = vrrp_len;
 175                                 computed_cksum = in_cksum(cksum_vec, 4);
 176                                 break;
 177                         case 2:
 178                         default:
 179                                 cksum_vec[0].ptr = tvb_get_ptr(tvb, 0, vrrp_len);
 180                                 cksum_vec[0].len = vrrp_len;
 181                                 computed_cksum = in_cksum(&cksum_vec[0], 1);
 182                                 break;
 183                         }
 184                         if (computed_cksum == 0) {
 185                                 proto_tree_add_text(vrrp_tree, tvb, offset, 2,
 186                                                     "Checksum: 0x%04x (correct)",
 187                                                     cksum);
 188                         } else {
 189                                 proto_tree_add_text(vrrp_tree, tvb, offset, 2,
 190                                                     "Checksum: 0x%04x (incorrect, should be 0x%04x)",
 191                                                     cksum,
 192                                                     in_cksum_shouldbe(cksum, computed_cksum));
 193                         }
 194                 } else {
 195                         proto_tree_add_text(vrrp_tree, tvb, offset, 2,
 196                                             "Checksum: 0x%04x", cksum);
 197                 }
 198                 offset+=2;
 199
 200                 switch(hi_nibble(ver_type)) {
 201                 case 3:
 202                         proto_tree_add_item(vrrp_tree, hf_vrrp_ip6, tvb, offset, 16, FALSE);
 203                         offset+=16;
 204                         break;
 205                 case 2:
 206                 default:
 207                         while (ip_count > 0) {
 208                                 proto_tree_add_item(vrrp_tree, hf_vrrp_ip, tvb,
 209                                     offset, 4, FALSE);
 210                                 offset+=4;
 211                                 ip_count--;
 212                         }
 213                         break;
 214                 }
 215                 if (auth_type != VRRP_AUTH_TYPE_SIMPLE_TEXT)
 216                         return; /* Contents of the authentication data is undefined */
 217
 218                 tvb_get_nstringz0(tvb, offset, sizeof auth_buf, auth_buf);
 219                 if (auth_buf[0] != '\0')
 220                         proto_tree_add_text(vrrp_tree, tvb, offset,
 221                                             VRRP_AUTH_DATA_LEN,
 222                                             "Authentication string: `%s'",
 223                                             auth_buf);
 224                 offset+=8;
 225         }
 226 }
 227
 228 void proto_register_vrrp(void)
 229 {
 230         static hf_register_info hf[] = {
 231                 { &hf_vrrp_ver_type,
 232                   {"VRRP message version and type", "vrrp.typever",
 233                    FT_UINT8, BASE_DEC, NULL, 0x0,
 234                    "VRRP version and type", HFILL }},
 235
 236                 { &hf_vrrp_version,
 237                   {"VRRP protocol version", "vrrp.version",
 238                    FT_UINT8, BASE_DEC, NULL, VRRP_VERSION_MASK,
 239                    "VRRP version", HFILL }},
 240
 241                 { &hf_vrrp_type,
 242                   {"VRRP packet type", "vrrp.type",
 243                    FT_UINT8, BASE_DEC, VALS(vrrp_type_vals), VRRP_TYPE_MASK,
 244                    "VRRP type", HFILL }},
 245
 246                 { &hf_vrrp_virt_rtr_id,
 247                   {"Virtual Rtr ID", "vrrp.virt_rtr_id",
 248                    FT_UINT8, BASE_DEC, NULL, 0x0,
 249                    "Virtual router this packet is reporting status for", HFILL }},
 250
 251                 { &hf_vrrp_prio,
 252                   {"Priority", "vrrp.prio",
 253                    FT_UINT8, BASE_DEC, NULL, 0x0,
 254                    "Sending VRRP router's priority for the virtual router", HFILL }},
 255
 256                 { &hf_vrrp_count_ip,
 257                   {"Count IP Addrs", "vrrp.count_ip_addrs",
 258                    FT_UINT8, BASE_DEC, NULL, 0x0,
 259                    "The number of IP addresses contained in this VRRP advertisement", HFILL }},
 260
 261                 { &hf_vrrp_auth_type,
 262                   {"Auth Type", "vrrp.auth_type",
 263                    FT_UINT8, BASE_DEC, VALS(vrrp_auth_vals), 0x0,
 264                    "The authentication method being utilized", HFILL }},
 265
 266                 { &hf_vrrp_adver_int,
 267                   {"Adver Int", "vrrp.adver_int",
 268                    FT_UINT8, BASE_DEC, NULL, 0x0,
 269                    "Time interval (in seconds) between ADVERTISEMENTS", HFILL }},
 270
 271                 { &hf_vrrp_ip,
 272                   {"IP Address", "vrrp.ip_addr",
 273                    FT_IPv4, 0, NULL, 0x0,
 274                    "IP address associated with the virtual router", HFILL }},
 275
 276                 { &hf_vrrp_ip6,
 277                   {"IPv6 Address", "vrrp.ipv6_addr",
 278                    FT_IPv6, 0, NULL, 0x0,
 279                    "IPv6 address associated with the virtual router", HFILL }},
 280         };
 281
 282         static gint *ett[] = {
 283                 &ett_vrrp,
 284                 &ett_vrrp_ver_type
 285         };
 286
 287         proto_vrrp = proto_register_protocol("Virtual Router Redundancy Protocol",
 288             "VRRP", "vrrp");
 289         proto_register_field_array(proto_vrrp, hf, array_length(hf));
 290         proto_register_subtree_array(ett, array_length(ett));
 291
 292         return;
 293 }
 294
 295 void
 296 proto_reg_handoff_vrrp(void)
 297 {
 298         dissector_handle_t vrrp_handle;
 299
 300         vrrp_handle = create_dissector_handle(dissect_vrrp, proto_vrrp);
 301         dissector_add("ip.proto", IP_PROTO_VRRP, vrrp_handle);
 302 }