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packet-rtse-template.c

/* packet-rtse_asn1.c
 * Routines for RTSE packet dissection
 * Graeme Lunt 2005
 *
 * $Id: packet-rtse-template.c 24116 2008-01-16 20:41:23Z stig $
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <glib.h>
#include <epan/packet.h>
#include <epan/conversation.h>
#include <epan/prefs.h>
#include <epan/reassemble.h>
#include <epan/asn1.h>

#include <stdio.h>
#include <string.h>

#include "packet-ber.h"
#include "packet-pres.h"
#include "packet-acse.h"
#include "packet-ros.h"
#include "packet-rtse.h"

#define PNAME  "X.228 OSI Reliable Transfer Service"
#define PSNAME "RTSE"
#define PFNAME "rtse"

/* Initialize the protocol and registered fields */
int proto_rtse = -1;

static struct SESSION_DATA_STRUCTURE* session = NULL;

static gboolean open_request=FALSE;
static guint32 app_proto=0;

static proto_tree *top_tree=NULL;

static  dissector_handle_t rtse_handle = NULL;
static  dissector_handle_t ros_handle = NULL;

/* Preferences */
static gboolean rtse_reassemble = TRUE;

#include "packet-rtse-hf.c"

/* Initialize the subtree pointers */
static gint ett_rtse = -1;
#include "packet-rtse-ett.c"


static dissector_table_t rtse_oid_dissector_table=NULL;
static GHashTable *oid_table=NULL;
static gint ett_rtse_unknown = -1;

static GHashTable *rtse_segment_table = NULL;
static GHashTable *rtse_reassembled_table = NULL;
 
static int hf_rtse_fragments = -1;
static int hf_rtse_fragment = -1;
static int hf_rtse_fragment_overlap = -1;
static int hf_rtse_fragment_overlap_conflicts = -1;
static int hf_rtse_fragment_multiple_tails = -1;
static int hf_rtse_fragment_too_long_fragment = -1;
static int hf_rtse_fragment_error = -1;
static int hf_rtse_reassembled_in = -1;

static gint ett_rtse_fragment = -1;
static gint ett_rtse_fragments = -1;

static const fragment_items rtse_frag_items = {
      /* Fragment subtrees */
      &ett_rtse_fragment,
      &ett_rtse_fragments,
      /* Fragment fields */
      &hf_rtse_fragments,
      &hf_rtse_fragment,
      &hf_rtse_fragment_overlap,
      &hf_rtse_fragment_overlap_conflicts,
      &hf_rtse_fragment_multiple_tails,
      &hf_rtse_fragment_too_long_fragment,
      &hf_rtse_fragment_error,
      /* Reassembled in field */
      &hf_rtse_reassembled_in,
      /* Tag */
      "RTSE fragments"
};

void
register_rtse_oid_dissector_handle(const char *oid, dissector_handle_t dissector, int proto _U_, const char *name, gboolean uses_ros)
{

  /* save the name - but not used */
  g_hash_table_insert(oid_table, (gpointer)oid, (gpointer)name);

  /* register RTSE with the BER (ACSE) */
  register_ber_oid_dissector_handle(oid, rtse_handle, proto, name);

  if(uses_ros) {
    /* make sure we call ROS ... */
    dissector_add_string("rtse.oid", oid, ros_handle);

    /* and then tell ROS how to dissect the AS*/
    register_ros_oid_dissector_handle(oid, dissector, proto, name, TRUE);

  } else {
    /* otherwise we just remember how to dissect the AS */
    dissector_add_string("rtse.oid", oid, dissector);
  }
}

static int
call_rtse_oid_callback(const char *oid, tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree)
{
      tvbuff_t *next_tvb;

      next_tvb = tvb_new_subset(tvb, offset, tvb_length_remaining(tvb, offset), tvb_reported_length_remaining(tvb, offset));
      if(!dissector_try_string(rtse_oid_dissector_table, oid, next_tvb, pinfo, tree)){
            proto_item *item=NULL;
            proto_tree *next_tree=NULL;

            item=proto_tree_add_text(tree, next_tvb, 0, tvb_length_remaining(tvb, offset), "RTSE: Dissector for OID:%s not implemented. Contact Wireshark developers if you want this supported", oid);
            if(item){
                  next_tree=proto_item_add_subtree(item, ett_rtse_unknown);
            }
            dissect_unknown_ber(pinfo, next_tvb, offset, next_tree);
      }

      /*XXX until we change the #.REGISTER signature for _PDU()s 
       * into new_dissector_t   we have to do this kludge with
       * manually step past the content in the ANY type.
       */
      offset+=tvb_length_remaining(tvb, offset);

      return offset;
}

static int
call_rtse_external_type_callback(gboolean implicit_tag _U_, tvbuff_t *tvb, int offset, asn1_ctx_t *actx, proto_tree *tree, int hf_index _U_)
{
      const char  *oid = NULL;

        if (actx->external.indirect_ref_present) {
            oid = (const char *)find_oid_by_pres_ctx_id(actx->pinfo, actx->external.indirect_reference);
      } else if (actx->external.direct_ref_present) {
            oid = actx->external.direct_reference;
      }

      if (oid)
            offset = call_rtse_oid_callback(oid, tvb, offset, actx->pinfo, top_tree ? top_tree : tree);

      return offset;
}

#include "packet-rtse-fn.c"

/*
* Dissect RTSE PDUs inside a PPDU.
*/
static void
dissect_rtse(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree)
{
      int offset = 0;
      int old_offset;
      proto_item *item=NULL;
      proto_tree *tree=NULL;
      tvbuff_t *next_tvb = NULL;
      tvbuff_t *data_tvb = NULL;
      fragment_data *frag_msg = NULL;
      guint32 fragment_length;
      guint32 rtse_id = 0;
      gboolean data_handled = FALSE;
      conversation_t *conversation = NULL;
      asn1_ctx_t asn1_ctx;
      asn1_ctx_init(&asn1_ctx, ASN1_ENC_BER, TRUE, pinfo);

      /* save parent_tree so subdissectors can create new top nodes */
      top_tree=parent_tree;

      /* do we have application context from the acse dissector?  */
      if( !pinfo->private_data ){
            if(parent_tree){
                  proto_tree_add_text(parent_tree, tvb, offset, -1,
                        "Internal error:can't get application context from ACSE dissector.");
            } 
            return  ;
      } else {
            session  = ( (struct SESSION_DATA_STRUCTURE*)(pinfo->private_data) );

      }

      if (check_col(pinfo->cinfo, COL_PROTOCOL))
            col_set_str(pinfo->cinfo, COL_PROTOCOL, "RTSE");
      if (check_col(pinfo->cinfo, COL_INFO))
            col_clear(pinfo->cinfo, COL_INFO);

      if (rtse_reassemble && 
          ((session->spdu_type == SES_DATA_TRANSFER) ||
           (session->spdu_type == SES_MAJOR_SYNC_POINT))) {
            /* Use conversation index as fragment id */
            conversation  = find_conversation (pinfo->fd->num, 
                                       &pinfo->src, &pinfo->dst, pinfo->ptype, 
                                       pinfo->srcport, pinfo->destport, 0);
            if (conversation != NULL) { 
                  rtse_id = conversation->index;
            } 
            session->rtse_reassemble = TRUE;
      }
      if (rtse_reassemble && session->spdu_type == SES_MAJOR_SYNC_POINT) {
            frag_msg = fragment_end_seq_next (pinfo, rtse_id, rtse_segment_table,
                                      rtse_reassembled_table);
            next_tvb = process_reassembled_data (tvb, offset, pinfo, "Reassembled RTSE", 
                                         frag_msg, &rtse_frag_items, NULL, parent_tree);
      }
      if(parent_tree){
            item = proto_tree_add_item(parent_tree, proto_rtse, next_tvb ? next_tvb : tvb, 0, -1, FALSE);
            tree = proto_item_add_subtree(item, ett_rtse);
      }
      if (rtse_reassemble && session->spdu_type == SES_DATA_TRANSFER) {
            /* strip off the OCTET STRING encoding - including any CONSTRUCTED OCTET STRING */
            dissect_ber_octet_string(FALSE, &asn1_ctx, NULL, tvb, offset, 0, &data_tvb);

            if (data_tvb) {
                  fragment_length = tvb_length_remaining (data_tvb, 0);
                  proto_tree_add_text(tree, data_tvb, 0, (fragment_length) ? -1 : 0,
                                  "RTSE segment data (%u byte%s)", fragment_length,
                                          plurality(fragment_length, "", "s"));
                  frag_msg = fragment_add_seq_next (data_tvb, 0, pinfo, 
                                            rtse_id, rtse_segment_table,
                                            rtse_reassembled_table, fragment_length, TRUE);
                  if (frag_msg && pinfo->fd->num != frag_msg->reassembled_in) {
                        /* Add a "Reassembled in" link if not reassembled in this frame */
                        proto_tree_add_uint (tree, *(rtse_frag_items.hf_reassembled_in),
                                         data_tvb, 0, 0, frag_msg->reassembled_in);
                  }
                  pinfo->fragmented = TRUE;
                  data_handled = TRUE;
            } else {
                  fragment_length = tvb_length_remaining (tvb, offset);
            }

            if (check_col(pinfo->cinfo, COL_INFO))
                  col_append_fstr(pinfo->cinfo, COL_INFO, "[RTSE fragment, %u byte%s]",
                              fragment_length, plurality(fragment_length, "", "s"));
      } else if (rtse_reassemble && session->spdu_type == SES_MAJOR_SYNC_POINT) {
            if (next_tvb) {
                  /* ROS won't do this for us */
                  session->ros_op = (ROS_OP_INVOKE | ROS_OP_ARGUMENT);
                  offset=dissect_ber_external_type(FALSE, tree, next_tvb, 0, &asn1_ctx, -1, call_rtse_external_type_callback);
            } else {
                  offset = tvb_length (tvb);
            }
            pinfo->fragmented = FALSE;
            data_handled = TRUE;
      } 

      if (!data_handled) {
            while (tvb_reported_length_remaining(tvb, offset) > 0){
                  old_offset=offset;
                  offset=dissect_rtse_RTSE_apdus(TRUE, tvb, offset, &asn1_ctx, tree, -1);
                  if(offset == old_offset){
                        proto_tree_add_text(tree, tvb, offset, -1, "Internal error, zero-byte RTSE PDU");
                        offset = tvb_length(tvb);
                        break;
                  }
            }
      }

      top_tree = NULL;
}

static void rtse_reassemble_init (void)
{
      fragment_table_init (&rtse_segment_table);
      reassembled_table_init (&rtse_reassembled_table);
}

/*--- proto_register_rtse -------------------------------------------*/
void proto_register_rtse(void) {

  /* List of fields */
  static hf_register_info hf[] =
  {
    /* Fragment entries */
    { &hf_rtse_fragments,
      { "RTSE fragments", "rtse.fragments", FT_NONE, BASE_NONE,
      NULL, 0x00, "Message fragments", HFILL } },
    { &hf_rtse_fragment,
      { "RTSE fragment", "rtse.fragment", FT_FRAMENUM, BASE_NONE,
      NULL, 0x00, "Message fragment", HFILL } },
    { &hf_rtse_fragment_overlap,
      { "RTSE fragment overlap", "rtse.fragment.overlap", FT_BOOLEAN,
      BASE_NONE, NULL, 0x00, "Message fragment overlap", HFILL } },
    { &hf_rtse_fragment_overlap_conflicts,
      { "RTSE fragment overlapping with conflicting data",
      "rtse.fragment.overlap.conflicts", FT_BOOLEAN, BASE_NONE, NULL,
      0x00, "Message fragment overlapping with conflicting data", HFILL } },
    { &hf_rtse_fragment_multiple_tails,
      { "RTSE has multiple tail fragments",
      "rtse.fragment.multiple_tails", FT_BOOLEAN, BASE_NONE,
      NULL, 0x00, "Message has multiple tail fragments", HFILL } },
    { &hf_rtse_fragment_too_long_fragment,
      { "RTSE fragment too long", "rtse.fragment.too_long_fragment",
      FT_BOOLEAN, BASE_NONE, NULL, 0x00, "Message fragment too long",
      HFILL } },
    { &hf_rtse_fragment_error,
      { "RTSE defragmentation error", "rtse.fragment.error", FT_FRAMENUM,
      BASE_NONE, NULL, 0x00, "Message defragmentation error", HFILL } },
    { &hf_rtse_reassembled_in,
      { "Reassembled RTSE in frame", "rtse.reassembled.in", FT_FRAMENUM, BASE_NONE,
      NULL, 0x00, "This RTSE packet is reassembled in this frame", HFILL } },

#include "packet-rtse-hfarr.c"
  };

  /* List of subtrees */
  static gint *ett[] = {
    &ett_rtse,
    &ett_rtse_unknown,
    &ett_rtse_fragment,
    &ett_rtse_fragments,
#include "packet-rtse-ettarr.c"
  };

  module_t *rtse_module;

  /* Register protocol */
  proto_rtse = proto_register_protocol(PNAME, PSNAME, PFNAME);
  register_dissector("rtse", dissect_rtse, proto_rtse);
  /* Register fields and subtrees */
  proto_register_field_array(proto_rtse, hf, array_length(hf));
  proto_register_subtree_array(ett, array_length(ett));
  register_init_routine (&rtse_reassemble_init);
  rtse_module = prefs_register_protocol_subtree("OSI", proto_rtse, NULL);

  prefs_register_bool_preference(rtse_module, "reassemble",
                         "Reassemble segmented RTSE datagrams",
                         "Whether segmented RTSE datagrams should be reassembled."
                         " To use this option, you must also enable"
                         " \"Allow subdissectors to reassemble TCP streams\""
                         " in the TCP protocol settings.", &rtse_reassemble);

  rtse_oid_dissector_table = register_dissector_table("rtse.oid", "RTSE OID Dissectors", FT_STRING, BASE_NONE);
  oid_table=g_hash_table_new(g_str_hash, g_str_equal);

  rtse_handle = find_dissector("rtse");
  ros_handle = find_dissector("ros");

}


/*--- proto_reg_handoff_rtse --- */
void proto_reg_handoff_rtse(void) {


}

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