epan/dissectors/packet-clip.c

   1 /* packet-clip.c
   2  * Routines for clip packet disassembly
   3  *
   4  * $Id$
   5  *
   6  * Wireshark - Network traffic analyzer
   7  * By Gerald Combs <gerald@wireshark.org>
   8  *
   9  * This file created by Thierry Andry <Thierry.Andry@advalvas.be>
  10  * from nearly-the-same packet-raw.c created by Mike Hall <mlh@io.com>
  11  * Copyright 1999
  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 #include "config.h"
  29
  30 #include <glib.h>
  31 #include <epan/packet.h>
  32 #include "packet-clip.h"
  33 #include "packet-ip.h"
  34
  35 void proto_register_clip(void);
  36 void proto_reg_handoff_clip(void);
  37
  38 static gint ett_clip = -1;
  39
  40 static dissector_handle_t ip_handle;
  41
  42 void
  43 capture_clip( const guchar *pd, int len, packet_counts *ld ) {
  44
  45     capture_ip(pd, 0, len, ld);
  46 }
  47
  48 static void
  49 dissect_clip(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
  50 {
  51   proto_tree    *fh_tree;
  52   proto_item    *ti;
  53
  54   pinfo->current_proto = "CLIP";
  55
  56   /* load the top pane info. This should be overwritten by
  57      the next protocol in the stack */
  58   col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "N/A");
  59   col_set_str(pinfo->cinfo, COL_RES_DL_DST, "N/A");
  60   col_set_str(pinfo->cinfo, COL_PROTOCOL, "CLIP");
  61   col_set_str(pinfo->cinfo, COL_INFO, "Classical IP frame");
  62
  63   /* populate a tree in the second pane with the status of the link
  64      layer (ie none)
  65
  66      XXX - the Linux Classical IP code supports both LLC Encapsulation,
  67      which puts an LLC header and possibly a SNAP header in front of
  68      the network-layer header, and VC Based Multiplexing, which puts
  69      no headers in front of the network-layer header.
  70
  71      The ATM on Linux code includes a patch to "tcpdump"
  72      that compares the first few bytes of the packet with the
  73      LLC header that Classical IP frames may have and, if there's
  74      a SNAP LLC header at the beginning of the packet, it gets
  75      the packet type from that header and uses that, otherwise
  76      it treats the packet as being raw IP with no link-level
  77      header, in order to handle both of those.
  78
  79      This code, however, won't handle LLC Encapsulation.  We've
  80      not yet seen a capture taken on a machine using LLC Encapsulation,
  81      however.  If we see one, we can modify the code.
  82
  83      A future version of libpcap, however, will probably use DLT_LINUX_SLL
  84      for both of those cases, to avoid the headache of having to
  85      generate capture-filter code to handle both of those cases. */
  86   if(tree) {
  87     ti = proto_tree_add_text(tree, tvb, 0, 0, "Classical IP frame" );
  88     fh_tree = proto_item_add_subtree(ti, ett_clip);
  89     proto_tree_add_text(fh_tree, tvb, 0, 0, "No link information available");
  90   }
  91   call_dissector(ip_handle, tvb, pinfo, tree);
  92 }
  93
  94 void
  95 proto_register_clip(void)
  96 {
  97   static gint *ett[] = {
  98     &ett_clip,
  99   };
 100
 101   proto_register_subtree_array(ett, array_length(ett));
 102 }
 103
 104 void
 105 proto_reg_handoff_clip(void)
 106 {
 107   dissector_handle_t clip_handle;
 108
 109   /*
 110    * Get a handle for the IP dissector.
 111    */
 112   ip_handle = find_dissector("ip");
 113
 114   clip_handle = create_dissector_handle(dissect_clip, -1);
 115       /* XXX - no protocol, can't be disabled */
 116   dissector_add_uint("wtap_encap", WTAP_ENCAP_LINUX_ATM_CLIP, clip_handle);
 117 }