epan/dissectors/packet-vrrp.c

   1 /* packet-vrrp.c
   2  * Routines for the Virtual Router Redundancy Protocol (VRRP)
   3  *
   4  * VRRPv2: RFC3768 (superseeding RFC2338)
   5  * VRRPv3: RFC5798
   6  *
   7  * Heikki Vatiainen <hessu@cs.tut.fi>
   8  *
   9  * $Id$
  10  *
  11  * Wireshark - Network traffic analyzer
  12  * By Gerald Combs <gerald@wireshark.org>
  13  * Copyright 1998 Gerald Combs
  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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  28  */
  29
  30 #include "config.h"
  31
  32 #include <glib.h>
  33 #include <epan/packet.h>
  34 #include <epan/ipproto.h>
  35 #include <epan/in_cksum.h>
  36 #include <epan/expert.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_addr_count = -1;
  48 static gint hf_vrrp_checksum = -1;
  49 static gint hf_vrrp_checksum_bad = -1;
  50 static gint hf_vrrp_auth_type = -1;
  51 static gint hf_vrrp_adver_int = -1;
  52 static gint hf_vrrp_reserved_mbz = -1;
  53 static gint hf_vrrp_short_adver_int = -1;
  54 static gint hf_vrrp_ip = -1;
  55 static gint hf_vrrp_ip6 = -1;
  56 static gint hf_vrrp_auth_string = -1;
  57
  58 static expert_field ei_vrrp_checksum = EI_INIT;
  59
  60 #define VRRP_VERSION_MASK 0xf0
  61 #define VRRP_TYPE_MASK 0x0f
  62 #define VRRP_AUTH_DATA_LEN 8
  63
  64 #define VRRP_TYPE_ADVERTISEMENT 1
  65 static const value_string vrrp_type_vals[] = {
  66     {VRRP_TYPE_ADVERTISEMENT, "Advertisement"},
  67     {0, NULL}
  68 };
  69
  70 #define VRRP_AUTH_TYPE_NONE 0
  71 #define VRRP_AUTH_TYPE_SIMPLE_TEXT 1
  72 #define VRRP_AUTH_TYPE_IP_AUTH_HDR 2
  73 static const value_string vrrp_auth_vals[] = {
  74     {VRRP_AUTH_TYPE_NONE,    "No Authentication"},
  75     {VRRP_AUTH_TYPE_SIMPLE_TEXT, "Simple Text Authentication [RFC 2338] / Reserved [RFC 3768]"},
  76     {VRRP_AUTH_TYPE_IP_AUTH_HDR, "IP Authentication Header [RFC 2338] / Reserved [RFC 3768]"},
  77     {0, NULL}
  78 };
  79
  80 #define VRRP_PRIORITY_MASTER_STOPPING 0
  81 /* Values between 1 and 254 inclusive are for backup VRRP routers */
  82 #define VRRP_PRIORITY_DEFAULT 100
  83 #define VRRP_PRIORITY_OWNER 255
  84 static const value_string vrrp_prio_vals[] = {
  85     {VRRP_PRIORITY_MASTER_STOPPING,  "Current Master has stopped participating in VRRP"},
  86     {VRRP_PRIORITY_DEFAULT,      "Default priority for a backup VRRP router"},
  87     {VRRP_PRIORITY_OWNER,        "This VRRP router owns the virtual router's IP address(es)"},
  88     {0, NULL }
  89 };
  90
  91
  92 static int
  93 dissect_vrrp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
  94 {
  95     int         offset = 0;
  96     gint        vrrp_len;
  97     guint8      ver_type;
  98     vec_t       cksum_vec[4];
  99     guint32     phdr[2];
 100     gboolean    is_ipv6;
 101     proto_item *ti, *tv, *hidden_item, *checksum_item;
 102     proto_tree *vrrp_tree, *ver_type_tree;
 103     guint8      priority, addr_count = 0, auth_type = VRRP_AUTH_TYPE_NONE;
 104     guint16     cksum, computed_cksum;
 105
 106     is_ipv6 = (pinfo->src.type == AT_IPv6);
 107
 108     col_set_str(pinfo->cinfo, COL_PROTOCOL, "VRRP");
 109     col_clear(pinfo->cinfo, COL_INFO);
 110
 111     ver_type = tvb_get_guint8(tvb, 0);
 112     col_add_fstr(pinfo->cinfo, COL_INFO, "Announcement (v%u)",
 113             hi_nibble(ver_type));
 114
 115     ti = proto_tree_add_item(tree, proto_vrrp, tvb, 0, -1, ENC_NA);
 116     vrrp_tree = proto_item_add_subtree(ti, ett_vrrp);
 117
 118     priority = tvb_get_guint8(tvb, 2);
 119     addr_count = tvb_get_guint8(tvb, 3);
 120
 121     tv = proto_tree_add_uint_format(vrrp_tree, hf_vrrp_ver_type,
 122             tvb, offset, 1, ver_type,
 123             "Version %u, Packet type %u (%s)",
 124             hi_nibble(ver_type), lo_nibble(ver_type),
 125             val_to_str_const(lo_nibble(ver_type), vrrp_type_vals, "Unknown"));
 126     ver_type_tree = proto_item_add_subtree(tv, ett_vrrp_ver_type);
 127
 128         if(ver_type_tree){
 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, ver_type);
 132                 offset++;
 133
 134                 proto_tree_add_item(vrrp_tree, hf_vrrp_virt_rtr_id, tvb, offset, 1, ENC_BIG_ENDIAN);
 135                 offset++;
 136
 137                 proto_tree_add_uint_format(vrrp_tree, hf_vrrp_prio, tvb, offset, 1, priority, "Priority: %u (%s)",
 138                                 priority,
 139                                 val_to_str_const(priority, vrrp_prio_vals, "Non-default backup priority"));
 140                 offset++;
 141
 142                 proto_tree_add_uint(vrrp_tree, hf_vrrp_addr_count, tvb,
 143                                 offset, 1, addr_count);
 144                 offset++;
 145
 146                 switch(hi_nibble(ver_type)) {
 147                         case 3:
 148                                 /* 4 bits reserved (mbz) + 12 bits interval */
 149                                 proto_tree_add_item(vrrp_tree, hf_vrrp_reserved_mbz, tvb, offset, 1, ENC_BIG_ENDIAN);
 150                                 proto_tree_add_item(vrrp_tree, hf_vrrp_short_adver_int, tvb, offset, 2, ENC_BIG_ENDIAN);
 151                                 offset+=2;
 152                                 break;
 153                         case 2:
 154                         default:
 155                                 /* 1 byte auth type + 1 byte interval */
 156                                 auth_type = tvb_get_guint8(tvb, offset);
 157                                 proto_tree_add_item(vrrp_tree, hf_vrrp_auth_type, tvb, offset, 1, ENC_BIG_ENDIAN);
 158                                 offset++;
 159
 160                                 proto_tree_add_item(vrrp_tree, hf_vrrp_adver_int, tvb, offset, 1, ENC_BIG_ENDIAN);
 161                                 offset++;
 162                                 break;
 163                 }
 164         }else{
 165                 offset+=6;
 166         }
 167
 168
 169     checksum_item = proto_tree_add_item(vrrp_tree, hf_vrrp_checksum, tvb, offset, 2, ENC_BIG_ENDIAN);
 170
 171     cksum = tvb_get_ntohs(tvb, offset);
 172     vrrp_len = (gint)tvb_reported_length(tvb);
 173     if (!pinfo->fragmented && (gint)tvb_length(tvb) >= vrrp_len) {
 174         /* The packet isn't part of a fragmented datagram
 175            and isn't truncated, so we can checksum it. */
 176         switch(hi_nibble(ver_type)) {
 177             case 3:
 178                 /* Set up the fields of the pseudo-header. */
 179                 cksum_vec[0].ptr = (guint8 *)pinfo->src.data;
 180                 cksum_vec[0].len = pinfo->src.len;
 181                 cksum_vec[1].ptr = (guint8 *)pinfo->dst.data;
 182                 cksum_vec[1].len = pinfo->dst.len;
 183                 cksum_vec[2].ptr = (const guint8 *)&phdr;
 184                 phdr[0] = g_htonl(vrrp_len);
 185                 phdr[1] = g_htonl(IP_PROTO_VRRP);
 186                 cksum_vec[2].len = 8;
 187                 cksum_vec[3].ptr = tvb_get_ptr(tvb, 0, vrrp_len);
 188                 cksum_vec[3].len = vrrp_len;
 189                 computed_cksum = in_cksum(cksum_vec, 4);
 190                 break;
 191             case 2:
 192             default:
 193                 cksum_vec[0].ptr = tvb_get_ptr(tvb, 0, vrrp_len);
 194                 cksum_vec[0].len = vrrp_len;
 195                 computed_cksum = in_cksum(&cksum_vec[0], 1);
 196                 break;
 197         }
 198
 199         if (computed_cksum == 0) {
 200             hidden_item = proto_tree_add_boolean(vrrp_tree, hf_vrrp_checksum_bad, tvb, offset, 2, FALSE);
 201             PROTO_ITEM_SET_HIDDEN(hidden_item);
 202             proto_item_append_text(checksum_item, " [correct]");
 203         } else {
 204             hidden_item = proto_tree_add_boolean(vrrp_tree, hf_vrrp_checksum_bad, tvb, offset, 2, TRUE);
 205             PROTO_ITEM_SET_HIDDEN(hidden_item);
 206             proto_item_append_text(checksum_item, " [incorrect, should be 0x%04x]", in_cksum_shouldbe(cksum, computed_cksum));
 207             expert_add_info_format(pinfo, checksum_item, &ei_vrrp_checksum,
 208                                    "VRRP Checksum Incorrect, should be 0x%04x", in_cksum_shouldbe(cksum, computed_cksum));
 209         }
 210
 211     }
 212     offset+=2;
 213
 214     while (addr_count > 0) {
 215         if (is_ipv6) {
 216             proto_tree_add_item(vrrp_tree, hf_vrrp_ip6, tvb, offset, 16, ENC_NA);
 217             offset+=16;
 218         } else {
 219             proto_tree_add_item(vrrp_tree, hf_vrrp_ip, tvb, offset, 4, ENC_BIG_ENDIAN);
 220             offset+=4;
 221         }
 222         addr_count--;
 223     }
 224
 225     if (auth_type == VRRP_AUTH_TYPE_SIMPLE_TEXT) {
 226         proto_tree_add_item(vrrp_tree, hf_vrrp_auth_string, tvb, offset, VRRP_AUTH_DATA_LEN, ENC_ASCII|ENC_NA);
 227         offset += VRRP_AUTH_DATA_LEN;
 228     }
 229
 230     return offset;
 231 }
 232
 233
 234 void proto_register_vrrp(void)
 235 {
 236     static hf_register_info hf[] = {
 237         { &hf_vrrp_ver_type,
 238             {"VRRP message version and type", "vrrp.typever",
 239                 FT_UINT8, BASE_DEC, NULL, 0x0,
 240                 "VRRP version and type", HFILL }},
 241
 242         { &hf_vrrp_version,
 243             {"VRRP protocol version", "vrrp.version",
 244                 FT_UINT8, BASE_DEC, NULL, VRRP_VERSION_MASK,
 245                 "VRRP version", HFILL }},
 246
 247         { &hf_vrrp_type,
 248             {"VRRP packet type", "vrrp.type",
 249                 FT_UINT8, BASE_DEC, VALS(vrrp_type_vals), VRRP_TYPE_MASK,
 250                 "VRRP type", HFILL }},
 251
 252         { &hf_vrrp_virt_rtr_id,
 253             {"Virtual Rtr ID", "vrrp.virt_rtr_id",
 254                 FT_UINT8, BASE_DEC, NULL, 0x0,
 255                 "Virtual router this packet is reporting status for", HFILL }},
 256
 257         { &hf_vrrp_prio,
 258             {"Priority", "vrrp.prio",
 259                 FT_UINT8, BASE_DEC, NULL, 0x0,
 260                 "Sending VRRP router's priority for the virtual router", HFILL }},
 261
 262         { &hf_vrrp_addr_count,
 263             {"Addr Count", "vrrp.addr_count",
 264                 FT_UINT8, BASE_DEC, NULL, 0x0,
 265                 "The number of addresses contained in this VRRP advertisement", HFILL }},
 266
 267         { &hf_vrrp_checksum,
 268             { "Checksum", "vrrp.checksum",
 269                 FT_UINT16, BASE_HEX, NULL, 0x0,
 270                 "Used to detect data corruption in the VRRP message", HFILL }},
 271
 272         { &hf_vrrp_checksum_bad,
 273           { "Bad Checksum", "vrrp.checksum_bad",
 274                 FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 275                 NULL, HFILL }},
 276
 277         { &hf_vrrp_auth_type,
 278             {"Auth Type", "vrrp.auth_type",
 279                 FT_UINT8, BASE_DEC, VALS(vrrp_auth_vals), 0x0,
 280                 "The authentication method being utilized", HFILL }},
 281
 282         { &hf_vrrp_adver_int,
 283             {"Adver Int", "vrrp.adver_int",
 284                 FT_UINT8, BASE_DEC, NULL, 0x0,
 285                 "Time interval (in seconds) between ADVERTISEMENTS", HFILL }},
 286
 287         { &hf_vrrp_reserved_mbz,
 288             {"Reserved", "vrrp.reserved_mbz",
 289                 FT_UINT8, BASE_DEC, NULL, 0xF0,
 290                 "Must be zero", HFILL }},
 291
 292         { &hf_vrrp_short_adver_int,
 293             {"Adver Int", "vrrp.short_adver_int",
 294                 FT_UINT16, BASE_DEC, NULL, 0x0FFF,
 295                 "Time interval (in centiseconds) between ADVERTISEMENTS", HFILL }},
 296
 297         { &hf_vrrp_ip,
 298             {"IP Address", "vrrp.ip_addr",
 299                 FT_IPv4, BASE_NONE, NULL, 0x0,
 300                 "IP address associated with the virtual router", HFILL }},
 301
 302         { &hf_vrrp_ip6,
 303             {"IPv6 Address", "vrrp.ipv6_addr",
 304                 FT_IPv6, BASE_NONE, NULL, 0x0,
 305                 "IPv6 address associated with the virtual router", HFILL }},
 306
 307         { &hf_vrrp_auth_string,
 308             {"Authentification String", "vrrp.auth_string",
 309                 FT_STRING, BASE_NONE, NULL, 0x0,
 310                 NULL, HFILL }},
 311     };
 312
 313     static gint *ett[] = {
 314         &ett_vrrp,
 315         &ett_vrrp_ver_type
 316     };
 317
 318     static ei_register_info ei[] = {
 319         { &ei_vrrp_checksum, { "vrrp.checksum_bad.expert", PI_CHECKSUM, PI_WARN, "Bad checksum", EXPFILL }},
 320     };
 321
 322     expert_module_t* expert_vrrp;
 323
 324
 325     proto_vrrp = proto_register_protocol("Virtual Router Redundancy Protocol",
 326             "VRRP", "vrrp");
 327     proto_register_field_array(proto_vrrp, hf, array_length(hf));
 328     proto_register_subtree_array(ett, array_length(ett));
 329
 330     expert_vrrp = expert_register_protocol(proto_vrrp);
 331     expert_register_field_array(expert_vrrp, ei, array_length(ei));
 332
 333 }
 334
 335 void
 336 proto_reg_handoff_vrrp(void)
 337 {
 338     dissector_handle_t vrrp_handle;
 339
 340     vrrp_handle = new_create_dissector_handle(dissect_vrrp, proto_vrrp);
 341     dissector_add_uint("ip.proto", IP_PROTO_VRRP, vrrp_handle);
 342 }
 343
 344 /*
 345  * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 346  *
 347  * Local variables:
 348  * c-basic-offset: 4
 349  * tab-width: 8
 350  * indent-tabs-mode: nil
 351  * End:
 352  *
 353  * vi: set shiftwidth=4 tabstop=8 expandtab:
 354  * :indentSize=4:tabSize=8:noTabs=true:
 355  */