epan/dissectors/packet-cisco-erspan.c

   1 /* packet-erspan.c
   2  * Routines for the disassembly of Cisco's ERSPAN protocol
   3  *
   4  * $Id$
   5  *
   6  * Copyright 2005 Joerg Mayer (see AUTHORS file)
   7  * Updates for newer versions by Jason Masker <jason at masker.net>
   8  *
   9  * Wireshark - Network traffic analyzer
  10  * By Gerald Combs <gerald@wireshark.org>
  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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  26  */
  27
  28 /*
  29  * TODO:
  30  *      Find out the Unknown values
  31  *
  32  * Specs:
  33  *      No real specs exist. Some general description can be found at:
  34  *      http://www.cisco.com/en/US/products/hw/routers/ps368/products_configuration_guide_chapter09186a008069952a.html
  35  *
  36  *      Some information on ERSPAN type III can be found at:
  37  *      http://www.cisco.com/en/US/docs/switches/datacenter/nexus1000/sw/4_0_4_s_v_1_3/system_management/configuration/guide/n1000v_system_9span.html
  38  *
  39  *      For ERSPAN packets, the "protocol type" field value in the GRE header
  40  *      is 0x88BE (version 1) or 0x22EB (version 2).
  41  *
  42  *      ERSPAN type II is version 1
  43  *      ERSPAN type III is version 2
  44  *
  45  * 0000000: d4c3 b2a1 0200 0400 0000 0000 0000 0000 <-- pcap header
  46  * 0000010: ffff 0000
  47  * 0000010:           7100 0000 <-- 0x71 (DLT_TYPE) = linux_cooked_capture (of course not)
  48  * 0000010:                     7507 f845 11d1 0500 <-- pcap record header
  49  * 0000020: 7a00 0000 7a00 0000
  50  * 0000020:                     0000 030a 0000 0000 <-- unknown
  51  * 0000030: 0000 0000
  52  * 0000030:           0000 88be <-- GRE header (version 1)
  53  * 0000030:                     1002 0001 0000 0380 <-- ERSPAN header (01: erspan-id)
  54  * 0000040: 00d0 b7a7 7480 0015 c721 75c0 0800 4500 <-- Ethernet packet
  55  * ...
  56  *
  57  *
  58  */
  59
  60 #include "config.h"
  61
  62 #include <glib.h>
  63 #include <epan/packet.h>
  64 #include <epan/greproto.h>
  65 #include <epan/prefs.h>
  66 #include <epan/expert.h>
  67
  68 static int proto_erspan = -1;
  69
  70 static gint ett_erspan = -1;
  71
  72 static int hf_erspan_version = -1;
  73 static int hf_erspan_vlan = -1;
  74 static int hf_erspan_priority = -1;
  75 static int hf_erspan_unknown2 = -1;
  76 static int hf_erspan_direction = -1;
  77 static int hf_erspan_unknown3 = -1;
  78 static int hf_erspan_truncated = -1;
  79 static int hf_erspan_spanid = -1;
  80 static int hf_erspan_timestamp = -1;
  81 static int hf_erspan_unknown4 = -1;
  82 static int hf_erspan_direction2 = -1;
  83 static int hf_erspan_unknown5 = -1;
  84 static int hf_erspan_unknown6 = -1;
  85 static int hf_erspan_unknown7 = -1;
  86
  87 static expert_field ei_erspan_version_unknown = EI_INIT;
  88
  89 #define PROTO_SHORT_NAME "ERSPAN"
  90 #define PROTO_LONG_NAME "Encapsulated Remote Switch Packet ANalysis"
  91
  92 /* Global ERSPAN Preference */
  93 static gboolean pref_fake_erspan = FALSE;
  94
  95 #define ERSPAN_DIRECTION_INCOMING 0
  96 #define ERSPAN_DIRECTION_OUTGOING 1
  97 static const value_string erspan_direction_vals[] = {
  98         {ERSPAN_DIRECTION_INCOMING, "Incoming"},
  99         {ERSPAN_DIRECTION_OUTGOING, "Outgoing"},
 100         {0, NULL},
 101 };
 102
 103 static const value_string erspan_truncated_vals[] = {
 104         {0, "Not truncated"},
 105         {1, "Truncated"},
 106         {0, NULL},
 107 };
 108
 109 static const value_string erspan_version_vals[] = {
 110         {1, "Type II"},
 111         {2, "Type III"},
 112         {0, NULL},
 113 };
 114
 115 static dissector_handle_t ethnofcs_handle;
 116
 117 static void
 118 erspan_fmt_timestamp(gchar *result, guint32 timeval)
 119 {
 120         g_snprintf(result, ITEM_LABEL_LENGTH, "%.4f", (((gfloat)timeval)/10000));
 121 }
 122
 123 static void
 124 dissect_erspan(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 125 {
 126         proto_item *ti;
 127         proto_item *ti_ver;
 128         proto_tree *erspan_tree = NULL;
 129         tvbuff_t *eth_tvb;
 130         guint32 offset = 0;
 131         guint16 version;
 132
 133         col_set_str(pinfo->cinfo, COL_PROTOCOL, PROTO_SHORT_NAME);
 134         col_set_str(pinfo->cinfo, COL_INFO, PROTO_SHORT_NAME ":");
 135
 136
 137         if (tree) {
 138                 ti = proto_tree_add_item(tree, proto_erspan, tvb, offset, -1,
 139                     ENC_NA);
 140                 erspan_tree = proto_item_add_subtree(ti, ett_erspan);
 141         }
 142
 143         if(pref_fake_erspan) {
 144                 /* Some vendor don't include ERSPAN Header...*/
 145                 eth_tvb = tvb_new_subset_remaining(tvb, offset);
 146                 call_dissector(ethnofcs_handle, eth_tvb, pinfo, tree);
 147                 return;
 148         }
 149
 150
 151         version = tvb_get_ntohs(tvb, offset) >> 12;
 152         if (tree) {
 153                 ti_ver = proto_tree_add_item(erspan_tree, hf_erspan_version, tvb, offset, 2,
 154                         ENC_BIG_ENDIAN);
 155                 if ((version != 1) && (version != 2 )) {
 156                         expert_add_info(pinfo, ti_ver, &ei_erspan_version_unknown);
 157                         return;
 158                 }
 159                 proto_tree_add_item(erspan_tree, hf_erspan_vlan, tvb, offset, 2,
 160                         ENC_BIG_ENDIAN);
 161                 offset += 2;
 162
 163                 proto_tree_add_item(erspan_tree, hf_erspan_priority, tvb, offset, 2,
 164                         ENC_BIG_ENDIAN);
 165                 proto_tree_add_item(erspan_tree, hf_erspan_unknown2, tvb, offset, 2,
 166                         ENC_BIG_ENDIAN);
 167                 if (version == 1)
 168                         proto_tree_add_item(erspan_tree, hf_erspan_direction, tvb,
 169                                 offset, 2, ENC_BIG_ENDIAN);
 170                 else /* version = 2 */
 171                         proto_tree_add_item(erspan_tree, hf_erspan_unknown3, tvb,
 172                                 offset, 2, ENC_BIG_ENDIAN);
 173                 proto_tree_add_item(erspan_tree, hf_erspan_truncated, tvb, offset, 2,
 174                         ENC_BIG_ENDIAN);
 175                 proto_tree_add_item(erspan_tree, hf_erspan_spanid, tvb, offset, 2,
 176                         ENC_BIG_ENDIAN);
 177                 offset += 2;
 178
 179                 if (version == 2) {
 180                         proto_tree_add_item(erspan_tree, hf_erspan_timestamp, tvb,
 181                                 offset, 4, ENC_BIG_ENDIAN);
 182                         offset += 4;
 183
 184                         proto_tree_add_item(erspan_tree, hf_erspan_unknown4, tvb,
 185                                 offset, 2, ENC_NA);
 186                         offset += 2;
 187
 188                         proto_tree_add_item(erspan_tree, hf_erspan_direction2, tvb,
 189                                 offset, 2, ENC_BIG_ENDIAN);
 190                         proto_tree_add_item(erspan_tree, hf_erspan_unknown5, tvb,
 191                                 offset, 2, ENC_BIG_ENDIAN);
 192                         offset += 2;
 193
 194                         proto_tree_add_item(erspan_tree, hf_erspan_unknown6, tvb,
 195                                 offset, 4, ENC_NA);
 196                         offset += 4;
 197                 }
 198                 proto_tree_add_item(erspan_tree, hf_erspan_unknown7, tvb, offset, 4,
 199                         ENC_NA);
 200                 offset += 4;
 201         }
 202         else {
 203                 offset += 8;
 204                 if (version == 2)
 205                         offset += 12;
 206         }
 207
 208         eth_tvb = tvb_new_subset_remaining(tvb, offset);
 209         call_dissector(ethnofcs_handle, eth_tvb, pinfo, tree);
 210 }
 211
 212 void
 213 proto_register_erspan(void)
 214 {
 215         module_t *erspan_module;
 216         expert_module_t* expert_erspan;
 217
 218         static hf_register_info hf[] = {
 219
 220                 { &hf_erspan_version,
 221                 { "Version",    "erspan.version", FT_UINT16, BASE_DEC, VALS(erspan_version_vals),
 222                         0xf000, NULL, HFILL }},
 223
 224                 { &hf_erspan_vlan,
 225                 { "Vlan",       "erspan.vlan", FT_UINT16, BASE_DEC, NULL,
 226                         0x0fff, NULL, HFILL }},
 227
 228                 { &hf_erspan_priority,
 229                 { "Priority",   "erspan.priority", FT_UINT16, BASE_DEC, NULL,
 230                         0xe000, NULL, HFILL }},
 231
 232                 { &hf_erspan_unknown2,
 233                 { "Unknown2",   "erspan.unknown2", FT_UINT16, BASE_DEC, NULL,
 234                         0x1000, NULL, HFILL }},
 235
 236                 { &hf_erspan_direction,
 237                 { "Direction",  "erspan.direction", FT_UINT16, BASE_DEC, VALS(erspan_direction_vals),
 238                         0x0800, NULL, HFILL }},
 239
 240                 { &hf_erspan_unknown3,
 241                 { "Unknown3",   "erspan.unknown3", FT_UINT16, BASE_DEC, NULL,
 242                         0x0800, NULL, HFILL }},
 243
 244                 { &hf_erspan_truncated,
 245                 { "Truncated",  "erspan.truncated", FT_UINT16, BASE_DEC, VALS(erspan_truncated_vals),
 246                         0x0400, "ERSPAN packet exceeded the MTU size", HFILL }},
 247
 248                 { &hf_erspan_spanid,
 249                 { "SpanID",     "erspan.spanid", FT_UINT16, BASE_DEC, NULL,
 250                         0x03ff, NULL, HFILL }},
 251
 252                 { &hf_erspan_timestamp,
 253                 { "Timestamp",  "erspan.timestamp", FT_UINT32, BASE_CUSTOM, erspan_fmt_timestamp,
 254                         0, NULL, HFILL }},
 255
 256                 { &hf_erspan_unknown4,
 257                 { "Unknown4",   "erspan.unknown4", FT_BYTES, BASE_NONE, NULL,
 258                         0, NULL, HFILL }},
 259
 260                 { &hf_erspan_direction2,
 261                 { "Direction2", "erspan.direction2", FT_UINT16, BASE_DEC, VALS(erspan_direction_vals),
 262                         0x0008, NULL, HFILL }},
 263
 264                 { &hf_erspan_unknown5,
 265                 { "Unknown5",   "erspan.unknown5", FT_UINT16, BASE_HEX, NULL,
 266                         0xfff7, NULL, HFILL }},
 267
 268                 { &hf_erspan_unknown6,
 269                 { "Unknown6",   "erspan.unknown6", FT_BYTES, BASE_NONE, NULL,
 270                         0, NULL, HFILL }},
 271
 272                 { &hf_erspan_unknown7,
 273                 { "Unknown7",   "erspan.unknown7", FT_BYTES, BASE_NONE, NULL,
 274                         0, NULL, HFILL }},
 275
 276         };
 277
 278         static gint *ett[] = {
 279                 &ett_erspan,
 280         };
 281
 282         static ei_register_info ei[] = {
 283                 { &ei_erspan_version_unknown, { "erspan.version.unknown", PI_UNDECODED, PI_WARN, "Unknown version, please report or test to use fake ERSPAN preference", EXPFILL }},
 284         };
 285
 286         proto_erspan = proto_register_protocol(PROTO_LONG_NAME, PROTO_SHORT_NAME, "erspan");
 287         proto_register_field_array(proto_erspan, hf, array_length(hf));
 288         proto_register_subtree_array(ett, array_length(ett));
 289         expert_erspan = expert_register_protocol(proto_erspan);
 290         expert_register_field_array(expert_erspan, ei, array_length(ei));
 291
 292         /* register dissection preferences */
 293         erspan_module = prefs_register_protocol(proto_erspan, NULL);
 294
 295         prefs_register_bool_preference(erspan_module, "fake_erspan",
 296                                 "FORCE to decode fake ERSPAN frame",
 297                                 "When set, dissector will FORCE to decode directly Ethernet Frame"
 298                                 "Some vendor use fake ERSPAN frame (with not ERSPAN Header)",
 299                                 &pref_fake_erspan);
 300 }
 301
 302 void
 303 proto_reg_handoff_erspan(void)
 304 {
 305         dissector_handle_t erspan_handle;
 306
 307         ethnofcs_handle = find_dissector("eth_withoutfcs");
 308
 309         erspan_handle = create_dissector_handle(dissect_erspan, proto_erspan);
 310         dissector_add_uint("gre.proto", GRE_ERSPAN_88BE, erspan_handle);
 311         dissector_add_uint("gre.proto", GRE_ERSPAN_22EB, erspan_handle);
 312
 313 }
 314