epan/dissectors/packet-vntag.c

   1 /* packet-vntag.c
   2  *
   3  * $Id$
   4  *
   5  * Wireshark - Network traffic analyzer
   6  * By Gerald Combs <gerald@wireshark.org>
   7  * Copyright 1998 Gerald Combs
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License
  11  * as published by the Free Software Foundation; either version 2
  12  * of the License, or (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  22  */
  23
  24 #include "config.h"
  25
  26 #include <glib.h>
  27 #include <epan/packet.h>
  28 #include <epan/etypes.h>
  29
  30 static int proto_vntag = -1;
  31
  32 static int hf_vntag_etype = -1;
  33 /* static int hf_vntag_len = -1; */
  34 static int hf_vntag_trailer = -1;
  35
  36 static gint ett_vntag = -1;
  37
  38 static void
  39 dissect_vntag(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
  40 {
  41         guint16     encap_proto;
  42         proto_tree *vntag_tree = NULL;
  43
  44         col_set_str(pinfo->cinfo, COL_PROTOCOL, "VNTAG");
  45         col_clear(pinfo->cinfo, COL_INFO);
  46
  47         if (tree) {
  48                 proto_item *ti = proto_tree_add_item(tree, proto_vntag, tvb, 0, 4, ENC_NA);
  49
  50                 vntag_tree = proto_item_add_subtree(ti, ett_vntag);
  51
  52                 /* XXX, 4 bytes of data */
  53
  54                 /* from scapy (http://hg.secdev.org/scapy-com/rev/37acec891993) GPLv2:
  55
  56                    BitField("dir",     0, 1),
  57                    BitField("ptr",     0, 1),
  58                    BitField("dst",     0, 14),
  59                    BitField("looped",  0, 1),
  60                    BitField("r",       0, 1),
  61                    BitField("version", 0, 2),
  62                    BitField("src",     0, 12) ]
  63                 */
  64                 /* another: http://www.definethecloud.net/access-layer-network-virtualization-vn-tag-and-vepa */
  65         }
  66
  67         encap_proto = tvb_get_ntohs(tvb, 4);
  68
  69         /* copied from packet-vlan.c do we need it also for VNTAG? */
  70 #if 0
  71         if (encap_proto <= IEEE_802_3_MAX_LEN) {
  72                 gboolean is_802_2;
  73
  74                 /* Is there an 802.2 layer? I can tell by looking at the first 2
  75                    bytes after the VLAN header. If they are 0xffff, then what
  76                    follows the VLAN header is an IPX payload, meaning no 802.2.
  77                    (IPX/SPX is they only thing that can be contained inside a
  78                    straight 802.3 packet, so presumably the same applies for
  79                    Ethernet VLAN packets). A non-0xffff value means that there's an
  80                    802.2 layer inside the VLAN layer */
  81                 is_802_2 = TRUE;
  82
  83                 /* Don't throw an exception for this check (even a BoundsError) */
  84                 if (tvb_length_remaining(tvb, 4) >= 2) {
  85                         if (tvb_get_ntohs(tvb, 4) == 0xffff)
  86                                 is_802_2 = FALSE;
  87                 }
  88
  89                 dissect_802_3(encap_proto, is_802_2, tvb, 4, pinfo, tree, vntag_tree, hf_vntag_len, hf_vntag_trailer, 0);
  90         } else
  91 #endif
  92                 ethertype(encap_proto, tvb, 6, pinfo, tree, vntag_tree, hf_vntag_etype, hf_vntag_trailer, 0);
  93 }
  94
  95 void
  96 proto_register_vntag(void)
  97 {
  98         static hf_register_info hf[] = {
  99                 { &hf_vntag_etype,
 100                         { "Type", "vntag.etype", FT_UINT16, BASE_HEX, VALS(etype_vals), 0x0, NULL, HFILL }
 101                 },
 102 #if 0
 103                 { &hf_vntag_len,
 104                         { "Length", "vntag.len", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL }
 105                 },
 106 #endif
 107                 { &hf_vntag_trailer,
 108                         { "Trailer", "vntag.trailer", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL }
 109                 }
 110         };
 111
 112         static gint *ett[] = {
 113                 &ett_vntag
 114         };
 115
 116         proto_vntag = proto_register_protocol("VN-Tag", "VNTAG", "vntag");
 117         proto_register_field_array(proto_vntag, hf, array_length(hf));
 118         proto_register_subtree_array(ett, array_length(ett));
 119 }
 120
 121 void
 122 proto_reg_handoff_vntag(void)
 123 {
 124         dissector_handle_t vntag_handle;
 125
 126         /* XXX, add 0x8926 define to epan/etypes.h && etype_vals */
 127
 128         vntag_handle = create_dissector_handle(dissect_vntag, proto_vntag);
 129         dissector_add_uint("ethertype", 0x8926, vntag_handle);
 130 }