epan/dissectors/packet-vlan.c

   1 /* packet-vlan.c
   2  * Routines for VLAN 802.1Q ethernet header disassembly
   3  *
   4  * $Id$
   5  *
   6  * Wireshark - Network traffic analyzer
   7  * By Gerald Combs <gerald@wireshark.org>
   8  * Copyright 1998 Gerald Combs
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License
  12  * as published by the Free Software Foundation; either version 2
  13  * of the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  23  */
  24
  25 #define NEW_PROTO_TREE_API
  26
  27 #include "config.h"
  28
  29 #include <glib.h>
  30 #include <epan/packet.h>
  31 #include <wsutil/pint.h>
  32 #include <epan/expert.h>
  33 #include "packet-ieee8023.h"
  34 #include "packet-ipx.h"
  35 #include "packet-llc.h"
  36 #include "packet-vlan.h"
  37 #include <epan/etypes.h>
  38 #include <epan/prefs.h>
  39
  40 void proto_reg_handoff_vlan(void);
  41
  42 static unsigned int q_in_q_ethertype = 0x9100;
  43
  44 static gboolean vlan_summary_in_tree = TRUE;
  45
  46
  47 static dissector_handle_t vlan_handle;
  48
  49 static header_field_info *hfi_vlan = NULL;
  50
  51 #define VLAN_HFI_INIT HFI_INIT(proto_vlan)
  52
  53 /* From Table G-2 of IEEE standard 802.1D-2004 */
  54 static const value_string pri_vals[] = {
  55   { 1, "Background"                        },
  56   { 2, "Spare"                             },
  57   { 0, "Best Effort (default)"             },
  58   { 3, "Excellent Effort"                  },
  59   { 4, "Controlled Load"                   },
  60   { 5, "Video, < 100ms latency and jitter" },
  61   { 6, "Voice, < 10ms latency and jitter"  },
  62   { 7, "Network Control"                   },
  63   { 0, NULL                                }
  64 };
  65
  66 static header_field_info hfi_vlan_priority VLAN_HFI_INIT = {
  67         "Priority", "vlan.priority", FT_UINT16, BASE_DEC,
  68         VALS(pri_vals), 0xE000, "Descriptions are recommendations from IEEE standard 802.1D-2004", HFILL };
  69
  70 static const value_string cfi_vals[] = {
  71   { 0, "Canonical"     },
  72   { 1, "Non-canonical" },
  73   { 0, NULL            }
  74 };
  75
  76 static header_field_info hfi_vlan_cfi VLAN_HFI_INIT = {
  77         "CFI", "vlan.cfi", FT_UINT16, BASE_DEC,
  78         VALS(cfi_vals), 0x1000, "Canonical Format Identifier", HFILL };
  79
  80 static header_field_info hfi_vlan_id VLAN_HFI_INIT = {
  81         "ID", "vlan.id", FT_UINT16, BASE_DEC,
  82         NULL, 0x0FFF, "VLAN ID", HFILL };
  83
  84 static header_field_info hfi_vlan_etype VLAN_HFI_INIT = {
  85         "Type", "vlan.etype", FT_UINT16, BASE_HEX,
  86         VALS(etype_vals), 0x0, "Ethertype", HFILL };
  87
  88 static header_field_info hfi_vlan_len VLAN_HFI_INIT = {
  89         "Length", "vlan.len", FT_UINT16, BASE_DEC,
  90         NULL, 0x0, NULL, HFILL };
  91
  92 static header_field_info hfi_vlan_trailer VLAN_HFI_INIT = {
  93         "Trailer", "vlan.trailer", FT_BYTES, BASE_NONE,
  94         NULL, 0x0, "VLAN Trailer", HFILL };
  95
  96
  97 static gint ett_vlan = -1;
  98
  99 static expert_field ei_vlan_len = EI_INIT;
 100
 101 void
 102 capture_vlan(const guchar *pd, int offset, int len, packet_counts *ld ) {
 103   guint16 encap_proto;
 104   if ( !BYTES_ARE_IN_FRAME(offset,len,5) ) {
 105     ld->other++;
 106     return;
 107   }
 108   encap_proto = pntohs( &pd[offset+2] );
 109   if ( encap_proto <= IEEE_802_3_MAX_LEN) {
 110     if ( pd[offset+4] == 0xff && pd[offset+5] == 0xff ) {
 111       capture_ipx(ld);
 112     } else {
 113       capture_llc(pd,offset+4,len,ld);
 114     }
 115   } else {
 116     capture_ethertype(encap_proto, pd, offset+4, len, ld);
 117   }
 118 }
 119
 120 static void
 121 dissect_vlan(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 122 {
 123   proto_item *ti;
 124   guint16 tci;
 125   volatile guint16 encap_proto;
 126   volatile gboolean is_802_2;
 127   proto_tree *volatile vlan_tree;
 128
 129   col_set_str(pinfo->cinfo, COL_PROTOCOL, "VLAN");
 130   col_clear(pinfo->cinfo, COL_INFO);
 131
 132   tci = tvb_get_ntohs( tvb, 0 );
 133
 134   col_add_fstr(pinfo->cinfo, COL_INFO, "PRI: %u  CFI: %u  ID: %u",
 135                (tci >> 13), ((tci >> 12) & 1), (tci & 0xFFF));
 136   col_add_fstr(pinfo->cinfo, COL_8021Q_VLAN_ID, "%u", (tci & 0xFFF));
 137
 138   vlan_tree = NULL;
 139
 140   if (tree) {
 141     ti = proto_tree_add_item(tree, hfi_vlan, tvb, 0, 4, ENC_NA);
 142
 143     if (vlan_summary_in_tree) {
 144         proto_item_append_text(ti, ", PRI: %u, CFI: %u, ID: %u",
 145                 (tci >> 13), ((tci >> 12) & 1), (tci & 0xFFF));
 146     }
 147
 148     vlan_tree = proto_item_add_subtree(ti, ett_vlan);
 149
 150     proto_tree_add_item(vlan_tree, &hfi_vlan_priority, tvb, 0, 2, ENC_BIG_ENDIAN);
 151     proto_tree_add_item(vlan_tree, &hfi_vlan_cfi, tvb, 0, 2, ENC_BIG_ENDIAN);
 152     proto_tree_add_item(vlan_tree, &hfi_vlan_id, tvb, 0, 2, ENC_BIG_ENDIAN);
 153   }
 154
 155   encap_proto = tvb_get_ntohs(tvb, 2);
 156   if (encap_proto <= IEEE_802_3_MAX_LEN) {
 157     /* Is there an 802.2 layer? I can tell by looking at the first 2
 158        bytes after the VLAN header. If they are 0xffff, then what
 159        follows the VLAN header is an IPX payload, meaning no 802.2.
 160        (IPX/SPX is they only thing that can be contained inside a
 161        straight 802.3 packet, so presumably the same applies for
 162        Ethernet VLAN packets). A non-0xffff value means that there's an
 163        802.2 layer inside the VLAN layer */
 164     is_802_2 = TRUE;
 165
 166     /* Don't throw an exception for this check (even a BoundsError) */
 167     if (tvb_length_remaining(tvb, 4) >= 2) {
 168       if (tvb_get_ntohs(tvb, 4) == 0xffff) {
 169         is_802_2 = FALSE;
 170       }
 171     }
 172
 173     dissect_802_3(encap_proto, is_802_2, tvb, 4, pinfo, tree, vlan_tree,
 174                   hfi_vlan_len.id, hfi_vlan_trailer.id, &ei_vlan_len, 0);
 175   } else {
 176     ethertype(encap_proto, tvb, 4, pinfo, tree, vlan_tree,
 177               hfi_vlan_etype.id, hfi_vlan_trailer.id, 0);
 178   }
 179 }
 180
 181 void
 182 proto_register_vlan(void)
 183 {
 184 #ifndef HAVE_HFI_SECTION_INIT
 185   static header_field_info *hfi[] = {
 186     &hfi_vlan_priority,
 187     &hfi_vlan_cfi,
 188     &hfi_vlan_id,
 189     &hfi_vlan_etype,
 190     &hfi_vlan_len,
 191     &hfi_vlan_trailer,
 192   };
 193 #endif /* HAVE_HFI_SECTION_INIT */
 194
 195   static gint *ett[] = {
 196     &ett_vlan
 197   };
 198
 199   static ei_register_info ei[] = {
 200      { &ei_vlan_len, { "vlan.len.past_end", PI_MALFORMED, PI_ERROR, "Length field value goes past the end of the payload", EXPFILL }},
 201   };
 202
 203   module_t *vlan_module;
 204   expert_module_t* expert_vlan;
 205   int proto_vlan;
 206
 207   proto_vlan = proto_register_protocol("802.1Q Virtual LAN", "VLAN", "vlan");
 208   hfi_vlan = proto_registrar_get_nth(proto_vlan);
 209
 210   proto_register_fields(proto_vlan, hfi, array_length(hfi));
 211   proto_register_subtree_array(ett, array_length(ett));
 212   expert_vlan = expert_register_protocol(proto_vlan);
 213   expert_register_field_array(expert_vlan, ei, array_length(ei));
 214
 215   vlan_module = prefs_register_protocol(proto_vlan, proto_reg_handoff_vlan);
 216   prefs_register_bool_preference(vlan_module, "summary_in_tree",
 217         "Show vlan summary in protocol tree",
 218         "Whether the vlan summary line should be shown in the protocol tree",
 219         &vlan_summary_in_tree);
 220   prefs_register_uint_preference(vlan_module, "qinq_ethertype",
 221         "802.1QinQ Ethertype (in hex)",
 222         "The (hexadecimal) Ethertype used to indicate 802.1QinQ VLAN in VLAN tunneling.",
 223         16, &q_in_q_ethertype);
 224
 225   vlan_handle = create_dissector_handle(dissect_vlan, proto_vlan);
 226 }
 227
 228 void
 229 proto_reg_handoff_vlan(void)
 230 {
 231   static gboolean prefs_initialized = FALSE;
 232   static unsigned int old_q_in_q_ethertype;
 233
 234   if (!prefs_initialized)
 235   {
 236     dissector_add_uint("ethertype", ETHERTYPE_VLAN, vlan_handle);
 237     prefs_initialized = TRUE;
 238   }
 239   else
 240   {
 241     dissector_delete_uint("ethertype", old_q_in_q_ethertype, vlan_handle);
 242   }
 243
 244   old_q_in_q_ethertype = q_in_q_ethertype;
 245
 246   dissector_add_uint("ethertype", q_in_q_ethertype, vlan_handle);
 247 }