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 1.23 2002/03/28 07:40:54 itojun 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 #ifdef HAVE_SYS_TYPES_H
  33 # include <sys/types.h>
  34 #endif
  35
  36 #ifdef HAVE_NETINET_IN_H
  37 #include <netinet/in.h>
  38 #endif
  39
  40 #include <string.h>
  41 #include <glib.h>
  42 #include <epan/packet.h>
  43 #include "ipproto.h"
  44 #include "in_cksum.h"
  45
  46 static gint proto_vrrp = -1;
  47 static gint ett_vrrp = -1;
  48 static gint ett_vrrp_ver_type = -1;
  49
  50 static gint hf_vrrp_ver_type = -1;
  51 static gint hf_vrrp_version = -1;
  52 static gint hf_vrrp_type = -1;
  53 static gint hf_vrrp_virt_rtr_id = -1;
  54 static gint hf_vrrp_prio = -1;
  55 static gint hf_vrrp_count_ip = -1;
  56 static gint hf_vrrp_auth_type = -1;
  57 static gint hf_vrrp_adver_int = -1;
  58 static gint hf_vrrp_ip = -1;
  59 static gint hf_vrrp_ip6 = -1;
  60
  61 #define VRRP_VERSION_MASK 0xf0
  62 #define VRRP_TYPE_MASK 0x0f
  63 #define VRRP_AUTH_DATA_LEN 8
  64
  65 #define VRRP_TYPE_ADVERTISEMENT 1
  66 static const value_string vrrp_type_vals[] = {
  67         {VRRP_TYPE_ADVERTISEMENT, "Advertisement"},
  68         {0, NULL}
  69 };
  70
  71 #define VRRP_AUTH_TYPE_NONE 0
  72 #define VRRP_AUTH_TYPE_SIMPLE_TEXT 1
  73 #define VRRP_AUTH_TYPE_IP_AUTH_HDR 2
  74 static const value_string vrrp_auth_vals[] = {
  75         {VRRP_AUTH_TYPE_NONE,        "No Authentication"},
  76         {VRRP_AUTH_TYPE_SIMPLE_TEXT, "Simple Text Authentication"},
  77         {VRRP_AUTH_TYPE_IP_AUTH_HDR, "IP Authentication Header"},
  78         {0,                          NULL}
  79 };
  80
  81 #define VRRP_PRIORITY_MASTER_STOPPING 0
  82 /* Values between 1 and 254 inclusive are for backup VRRP routers */
  83 #define VRRP_PRIORITY_DEFAULT 100
  84 #define VRRP_PRIORITY_OWNER 255
  85 static const value_string vrrp_prio_vals[] = {
  86         {VRRP_PRIORITY_MASTER_STOPPING,  "Current Master has stopped participating in VRRP"},
  87         {VRRP_PRIORITY_DEFAULT,          "Default priority for a backup VRRP router"},
  88         {VRRP_PRIORITY_OWNER,            "This VRRP router owns the virtual router's IP address(es)"},
  89         {0,                              NULL }
  90 };
  91
  92
  93 static void
  94 dissect_vrrp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
  95 {
  96         int offset = 0;
  97         gint vrrp_len;
  98         guint8  ver_type;
  99         vec_t cksum_vec[4];
 100         guint32 phdr[2];
 101
 102         if (check_col(pinfo->cinfo, COL_PROTOCOL))
 103                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "VRRP");
 104         if (check_col(pinfo->cinfo, COL_INFO))
 105                 col_clear(pinfo->cinfo, COL_INFO);
 106
 107         ver_type = tvb_get_guint8(tvb, 0);
 108         if (check_col(pinfo->cinfo, COL_INFO)) {
 109                 col_add_fstr(pinfo->cinfo, COL_INFO, "%s (v%u)",
 110                              "Announcement", hi_nibble(ver_type));
 111         }
 112
 113         if (tree) {
 114                 proto_item *ti, *tv;
 115                 proto_tree *vrrp_tree, *ver_type_tree;
 116                 guint8 priority, ip_count = 0, auth_type;
 117                 guint16 cksum, computed_cksum;
 118                 guint8 auth_buf[VRRP_AUTH_DATA_LEN+1];
 119
 120                 ti = proto_tree_add_item(tree, proto_vrrp, tvb, 0, -1, FALSE);
 121                 vrrp_tree = proto_item_add_subtree(ti, ett_vrrp);
 122
 123                 tv = proto_tree_add_uint_format(vrrp_tree, hf_vrrp_ver_type,
 124                                                 tvb, offset, 1, ver_type,
 125                                                 "Version %u, Packet type %u (%s)",
 126                                                 hi_nibble(ver_type), lo_nibble(ver_type),
 127                                                 val_to_str(lo_nibble(ver_type), vrrp_type_vals, "Unknown"));
 128                 ver_type_tree = proto_item_add_subtree(tv, ett_vrrp_ver_type);
 129                 proto_tree_add_uint(ver_type_tree, hf_vrrp_version, tvb,
 130                                     offset, 1, ver_type);
 131                 proto_tree_add_uint(ver_type_tree, hf_vrrp_type, tvb, offset, 1,
 132                                     ver_type);
 133                 offset++;
 134
 135                 proto_tree_add_item(vrrp_tree, hf_vrrp_virt_rtr_id, tvb, offset, 1, FALSE);
 136                 offset++;
 137
 138                 priority = tvb_get_guint8(tvb, offset);
 139                 proto_tree_add_uint_format(vrrp_tree, hf_vrrp_prio, tvb, offset, 1, priority, "Priority: %u (%s)",
 140                                            priority,
 141                                            val_to_str(priority, vrrp_prio_vals, "Non-default backup priority"));
 142                 offset++;
 143
 144                 switch(hi_nibble(ver_type)) {
 145                 case 3:
 146                         /* Skip reserve field */
 147                         offset++;
 148                         break;
 149                 case 2:
 150                 default:
 151                         ip_count = tvb_get_guint8(tvb, offset);
 152                         proto_tree_add_uint(vrrp_tree, hf_vrrp_count_ip, tvb,
 153                             offset, 1, ip_count);
 154                         offset++;
 155                         break;
 156                 }
 157
 158                 auth_type = tvb_get_guint8(tvb, offset);
 159                 proto_tree_add_item(vrrp_tree, hf_vrrp_auth_type, tvb, offset, 1, FALSE);
 160                 offset++;
 161
 162                 proto_tree_add_item(vrrp_tree, hf_vrrp_adver_int, tvb, offset, 1, FALSE);
 163                 offset++;
 164
 165                 cksum = tvb_get_ntohs(tvb, offset);
 166                 vrrp_len = (gint)tvb_reported_length(tvb);
 167                 if (!pinfo->fragmented && (gint)tvb_length(tvb) >= vrrp_len) {
 168                         /* The packet isn't part of a fragmented datagram
 169                            and isn't truncated, so we can checksum it. */
 170                         switch(hi_nibble(ver_type)) {
 171                         case 3:
 172                                 /* Set up the fields of the pseudo-header. */
 173                                 cksum_vec[0].ptr = pinfo->src.data;
 174                                 cksum_vec[0].len = pinfo->src.len;
 175                                 cksum_vec[1].ptr = pinfo->dst.data;
 176                                 cksum_vec[1].len = pinfo->dst.len;
 177                                 cksum_vec[2].ptr = (const guint8 *)&phdr;
 178                                 phdr[0] = htonl(vrrp_len);
 179                                 phdr[1] = htonl(IP_PROTO_VRRP);
 180                                 cksum_vec[2].len = 8;
 181                                 cksum_vec[3].ptr = tvb_get_ptr(tvb, 0, vrrp_len);
 182                                 cksum_vec[3].len = vrrp_len;
 183                                 computed_cksum = in_cksum(cksum_vec, 4);
 184                                 break;
 185                         case 2:
 186                         default:
 187                                 cksum_vec[0].ptr = tvb_get_ptr(tvb, 0, vrrp_len);
 188                                 cksum_vec[0].len = vrrp_len;
 189                                 computed_cksum = in_cksum(&cksum_vec[0], 1);
 190                                 break;
 191                         }
 192                         if (computed_cksum == 0) {
 193                                 proto_tree_add_text(vrrp_tree, tvb, offset, 2,
 194                                                     "Checksum: 0x%04x (correct)",
 195                                                     cksum);
 196                         } else {
 197                                 proto_tree_add_text(vrrp_tree, tvb, offset, 2,
 198                                                     "Checksum: 0x%04x (incorrect, should be 0x%04x)",
 199                                                     cksum,
 200                                                     in_cksum_shouldbe(cksum, computed_cksum));
 201                         }
 202                 } else {
 203                         proto_tree_add_text(vrrp_tree, tvb, offset, 2,
 204                                             "Checksum: 0x%04x", cksum);
 205                 }
 206                 offset+=2;
 207
 208                 switch(hi_nibble(ver_type)) {
 209                 case 3:
 210                         proto_tree_add_item(vrrp_tree, hf_vrrp_ip6, tvb, offset, 16, FALSE);
 211                         offset+=16;
 212                         break;
 213                 case 2:
 214                 default:
 215                         while (ip_count > 0) {
 216                                 proto_tree_add_item(vrrp_tree, hf_vrrp_ip, tvb,
 217                                     offset, 4, FALSE);
 218                                 offset+=4;
 219                                 ip_count--;
 220                         }
 221                         break;
 222                 }
 223                 if (auth_type != VRRP_AUTH_TYPE_SIMPLE_TEXT)
 224                         return; /* Contents of the authentication data is undefined */
 225
 226                 tvb_get_nstringz0(tvb, offset, VRRP_AUTH_DATA_LEN, auth_buf);
 227                 if (auth_buf[0] != '\0')
 228                         proto_tree_add_text(vrrp_tree, tvb, offset,
 229                                             VRRP_AUTH_DATA_LEN,
 230                                             "Authentication string: `%s'",
 231                                             auth_buf);
 232                 offset+=8;
 233         }
 234 }
 235
 236 void proto_register_vrrp(void)
 237 {
 238         static hf_register_info hf[] = {
 239                 { &hf_vrrp_ver_type,
 240                   {"VRRP message version and type", "vrrp.typever",
 241                    FT_UINT8, BASE_DEC, NULL, 0x0,
 242                    "VRRP version and type", HFILL }},
 243
 244                 { &hf_vrrp_version,
 245                   {"VRRP protocol version", "vrrp.version",
 246                    FT_UINT8, BASE_DEC, NULL, VRRP_VERSION_MASK,
 247                    "VRRP version", HFILL }},
 248
 249                 { &hf_vrrp_type,
 250                   {"VRRP packet type", "vrrp.type",
 251                    FT_UINT8, BASE_DEC, VALS(vrrp_type_vals), VRRP_TYPE_MASK,
 252                    "VRRP type", HFILL }},
 253
 254                 { &hf_vrrp_virt_rtr_id,
 255                   {"Virtual Rtr ID", "vrrp.virt_rtr_id",
 256                    FT_UINT8, BASE_DEC, NULL, 0x0,
 257                    "Virtual router this packet is reporting status for", HFILL }},
 258
 259                 { &hf_vrrp_prio,
 260                   {"Priority", "vrrp.prio",
 261                    FT_UINT8, BASE_DEC, NULL, 0x0,
 262                    "Sending VRRP router's priority for the virtual router", HFILL }},
 263
 264                 { &hf_vrrp_count_ip,
 265                   {"Count IP Addrs", "vrrp.count_ip_addrs",
 266                    FT_UINT8, BASE_DEC, NULL, 0x0,
 267                    "The number of IP addresses contained in this VRRP advertisement", HFILL }},
 268
 269                 { &hf_vrrp_auth_type,
 270                   {"Auth Type", "vrrp.auth_type",
 271                    FT_UINT8, BASE_DEC, VALS(vrrp_auth_vals), 0x0,
 272                    "The authentication method being utilized", HFILL }},
 273
 274                 { &hf_vrrp_adver_int,
 275                   {"Adver Int", "vrrp.adver_int",
 276                    FT_UINT8, BASE_DEC, NULL, 0x0,
 277                    "Time interval (in seconds) between ADVERTISEMENTS", HFILL }},
 278
 279                 { &hf_vrrp_ip,
 280                   {"IP Address", "vrrp.ip_addr",
 281                    FT_IPv4, 0, NULL, 0x0,
 282                    "IP address associated with the virtual router", HFILL }},
 283
 284                 { &hf_vrrp_ip6,
 285                   {"IPv6 Address", "vrrp.ipv6_addr",
 286                    FT_IPv6, 0, NULL, 0x0,
 287                    "IPv6 address associated with the virtual router", HFILL }},
 288         };
 289
 290         static gint *ett[] = {
 291                 &ett_vrrp,
 292                 &ett_vrrp_ver_type
 293         };
 294
 295         proto_vrrp = proto_register_protocol("Virtual Router Redundancy Protocol",
 296             "VRRP", "vrrp");
 297         proto_register_field_array(proto_vrrp, hf, array_length(hf));
 298         proto_register_subtree_array(ett, array_length(ett));
 299
 300         return;
 301 }
 302
 303 void
 304 proto_reg_handoff_vrrp(void)
 305 {
 306         dissector_handle_t vrrp_handle;
 307
 308         vrrp_handle = create_dissector_handle(dissect_vrrp, proto_vrrp);
 309         dissector_add("ip.proto", IP_PROTO_VRRP, vrrp_handle);
 310 }