Ralf Schneider's changes to enhance to OSI CLNP, CLTP, and ISIS support

and to add OSI ESIS support.

svn path=/trunk/; revision=1865

1 files changed, 132 insertions, 1732 deletions

diff --git a/packet-osi.c b/packet-osi.c
index ebd5c015a4..2b242597b6 100644
--- a/packet-osi.c
+++ b/packet-osi.c
@@ -1,8 +1,10 @@
 /* packet-osi.c
  * Routines for ISO/OSI network and transport protocol packet disassembly
+ * Main entrance point and common functions
  *
- * $Id: packet-osi.c,v 1.29 2000/04/15 21:27:12 guy Exp $
+ * $Id: packet-osi.c,v 1.30 2000/04/15 22:11:12 guy Exp $
  * Laurent Deniel <deniel@worldnet.fr>
+ * Ralf Schneider <Ralf.Schneider@t-online.de>
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@zing.org>
@@ -26,9 +28,9 @@
  *
  * To do:
  *
- * - add other network protocols (ES,IS-IS)
+ * - add other network protocols (IS-IS)
  * - add NSAP decoding & resolution
- * - complete CLNP decoding (options)
+ * 
  *
  */
 
@@ -45,1693 +47,161 @@
 #include <ctype.h>
 #include <glib.h>
 #include "packet.h"
-#include "packet-isis.h"
 #include "packet-h1.h"
 #include "nlpid.h"
+#include "packet-osi.h"
+#include "packet-clnp.h"
+#include "packet-isis.h"
+#include "packet-esis.h"
 
-/* protocols and fields */
-
-static int proto_clnp = -1;
-
-static int hf_clnp_id = -1;
-static int hf_clnp_length = -1;
-static int hf_clnp_version = -1;
-static int hf_clnp_ttl = -1;
-static int hf_clnp_type = -1;
-static int hf_clnp_pdu_length = -1;
-static int hf_clnp_checksum = -1;
-static int hf_clnp_dest_length = -1;
-static int hf_clnp_dest = -1;
-static int hf_clnp_src_length = -1;
-static int hf_clnp_src = -1;
-
-static gint ett_clnp = -1;
-
-static int proto_cotp = -1;
-
-static gint ett_cotp = -1;
-
-/*
- * ISO8473 OSI CLNP definition (see RFC994)
- *
- *            _________________________________
- *           |           Fixed Part            |
- *           |_________________________________|
- *           |          Address Part           |
- *           |_________________________________|
- *           |   Segmentation Part (optional)  |
- *           |_________________________________|
- *           |     Options Part (optional)     |
- *           |_________________________________|
- *           |         Data (optional)         |
- *           |_________________________________|
- */
-
-#define	ISO8473_V1		0x01	/* CLNP version 1 */
-
-/* Fixed part */
-
-struct clnp_header {
-  u_char	cnf_proto_id;	/* network layer protocol identifier */
-  u_char	cnf_hdr_len;	/* length indicator (octets) */
-  u_char	cnf_vers;	/* version/protocol identifier extension */
-  u_char	cnf_ttl;      	/* lifetime (500 milliseconds) */
-  u_char	cnf_type;      	/* type code */
-  u_char	cnf_seglen_msb;	/* pdu segment length (octets) high byte */
-  u_char	cnf_seglen_lsb;	/* pdu segment length (octets) low byte */
-  u_char	cnf_cksum_msb;	/* checksum high byte */
-  u_char	cnf_cksum_lsb;	/* checksum low byte */
-};
-
-#define CNF_TYPE		0x1f
-#define CNF_ERR_OK		0x20
-#define CNF_MORE_SEGS		0x40
-#define CNF_SEG_OK		0x80
-
-#define DT_NPDU			0x1C
-#define MD_NPDU			0x1D
-#define ER_NPDU			0x01
-#define ERQ_NPDU		0x1E
-#define ERP_NPDU		0x1F
-
-static const value_string npdu_type_vals[] = {
-  { DT_NPDU,	"DT" },
-  { MD_NPDU,	"MD" },
-  { ER_NPDU,	"ER" },
-  { ERQ_NPDU,	"ERQ" },
-  { ERP_NPDU,	"ERP" },
-  { 0,		NULL }
-};
-
-/* field position */
-
-#define P_ADDRESS_PART		9
-
-/* Segmentation part */
-
-struct clnp_segment {
-  u_short	cng_id;		/* data unit identifier */
-  u_short	cng_off;	/* segment offset */
-  u_short	cng_tot_len;	/* total length */
-};
-
-/* NSAP selector */
-
-#define NSEL_NET 		0x00
-#define NSEL_NP  		0x20
-#define NSEL_TP  		0x21
-
-/*
- * ISO8073 OSI COTP definition (see RFC905)
- */
-
-/* don't use specific TPDU types to avoid alignment problems & copy overhead */
-
-/* TPDU definition */
-
-#define ED_TPDU        		0x1
-#define EA_TPDU        		0x2
-#define RJ_TPDU        		0x5
-#define AK_TPDU        		0x6
-#define ER_TPDU        		0x7
-#define DR_TPDU        		0x8
-#define DC_TPDU        		0xC
-#define CC_TPDU        		0xD
-#define CR_TPDU        		0xE
-#define DT_TPDU        		0xF
-
-/* field position */
-
-#define P_LI           		0
-#define P_TPDU         		1
-#define P_CDT          		1
-#define P_DST_REF      		2
-#define P_SRC_REF      		4
-#define P_TPDU_NR_0_1  		2
-#define P_TPDU_NR_234  		4
-#define P_VAR_PART_NDT 		5
-#define P_VAR_PART_EDT 		8
-#define P_VAR_PART_NAK 		5
-#define P_VAR_PART_CC  		7
-#define P_VAR_PART_EAK 		10
-#define P_VAR_PART_DC           6
-#define P_VAR_PART_DR		7
-#define P_CDT_IN_AK    		8
-#define P_CDT_IN_RJ    		8
-#define P_REJECT_ER    		4
-#define P_REASON_IN_DR 		6
-#define P_CLASS_OPTION 		6
-
-/* TPDU length indicator */
-
-#define LI_NORMAL_DT_CLASS_01		 2
-#define LI_NORMAL_DT_WITH_CHECKSUM       8
-#define LI_NORMAL_DT_WITHOUT_CHECKSUM    4
-#define LI_EXTENDED_DT_WITH_CHECKSUM     11
-#define LI_EXTENDED_DT_WITHOUT_CHECKSUM  7
-#define LI_NORMAL_EA_WITH_CHECKSUM       8
-#define LI_NORMAL_EA_WITHOUT_CHECKSUM    4
-#define LI_EXTENDED_EA_WITH_CHECKSUM     11
-#define LI_EXTENDED_EA_WITHOUT_CHECKSUM  7
-#define LI_NORMAL_RJ                     4
-#define LI_EXTENDED_RJ                   9
-#define LI_MIN_DR                        6
-#define LI_MAX_DC                        9
-#define LI_MAX_AK                        27
-#define LI_MAX_EA                        11
-#define LI_MAX_ER			 8
-#define LI_DC_WITH_CHECKSUM		 9
-#define LI_DC_WITHOUT_CHECKSUM           5
-#define is_LI_NORMAL_AK(p)               ( p & 0x01 )
-
-/* variant part */
-
-#define VP_ACK_TIME     	0x85
-#define VP_RES_ERROR    	0x86
-#define VP_PRIORITY     	0x87
-#define VP_TRANSIT_DEL  	0x88
-#define VP_THROUGHPUT   	0x89
-#define VP_SEQ_NR       	0x8A         /* in AK */
-#define VP_REASSIGNMENT 	0x8B
-#define VP_FLOW_CNTL    	0x8C         /* in AK */
-#define VP_TPDU_SIZE    	0xC0
-#define VP_SRC_TSAP     	0xC1         /* in CR/CC */
-#define VP_DST_TSAP     	0xC2
-#define VP_CHECKSUM     	0xC3
-#define VP_VERSION_NR   	0xC4
-#define VP_PROTECTION   	0xC5
-#define VP_OPT_SEL      	0xC6
-#define VP_PROTO_CLASS  	0xC7
-
-/* misc */
-
-#define EXTRACT_SHORT(p) 	pntohs(p)
-#define EXTRACT_LONG(p) 	pntohl(p)
-
-/* global variables */
-
-static u_char  li, tpdu, cdt; 	/* common fields */
-static u_short dst_ref;
-
-/* function definitions */
-
-static int osi_decode_DR(const u_char *pd, int offset, 
-			 frame_data *fd, proto_tree *tree) 
-{
-  proto_tree *cotp_tree;
-  proto_item *ti;
-  u_short src_ref;
-  u_char  reason;
-  char *str;
-  
-  if (li < LI_MIN_DR) 
-    return -1;
-  
-  src_ref = EXTRACT_SHORT(&pd[offset + P_SRC_REF]);
-  reason  = pd[offset + P_REASON_IN_DR];
-
-  switch(reason) {
-    case (128+0): str = "Normal Disconnect"; break;
-    case (128+1): str = "Remote transport entity congestion"; break;
-    case (128+2): str = "Connection negotiation failed"; break;
-    case (128+3): str = "Duplicate source reference"; break;
-    case (128+4): str = "Mismatched references"; break;
-    case (128+5): str = "Protocol error"; break;
-    case (128+7): str = "Reference overflow"; break;
-    case (128+8): str = "Connection requestion refused"; break;
-    case (128+10):str = "Header or parameter length invalid"; break;
-    case (0):     str = "Reason not specified"; break;
-    case (1):     str = "Congestion at TSAP"; break;
-    case (2):     str = "Session entity not attached to TSAP"; break;
-    case (3):     str = "Address unknown"; break;
-    default:      return -1;
-      /*NOTREACHED*/
-      break;
-  }
-
-  if (check_col(fd, COL_INFO))
-    col_append_fstr(fd, COL_INFO, "DR TPDU src-ref: 0x%04x dst-ref: 0x%04x",
-		 src_ref, dst_ref);
-
-  if (tree) {
-    ti = proto_tree_add_item(tree, proto_cotp, offset, li + 1, NULL);
-    cotp_tree = proto_item_add_subtree(ti, ett_cotp);
-    proto_tree_add_text(cotp_tree, offset,      1,
-			"Length indicator: %d", li);
-    proto_tree_add_text(cotp_tree, offset +  1, 1, 
-			"TPDU code: 0x%x (DR)", tpdu); 
-    proto_tree_add_text(cotp_tree, offset +  2, 2, 
-			"Destination reference: 0x%04x", dst_ref);
-    proto_tree_add_text(cotp_tree, offset +  4, 2, 
-			"Source reference: 0x%04x", src_ref);
-    proto_tree_add_text(cotp_tree, offset +  6, 1, 
-			"Cause: %s", str);
-  }
-
-  offset += li + 1;
-  dissect_data(pd, offset, fd, tree);
-
-  return pi.captured_len;	/* we dissected all of the containing PDU */
-
-} /* osi_decode_DR */
-
-/* Returns TRUE if we called a sub-dissector, FALSE if not. */
-static gboolean osi_decode_DT(const u_char *pd, int offset, 
-			 frame_data *fd, proto_tree *tree,
-			 gboolean uses_inactive_subset)
-{
-  proto_tree *cotp_tree;
-  proto_item *ti;
-  u_int    tpdu_nr ;
-  u_short  checksum = 0;
-  u_char   code = 0, length = 0;
-  u_int    fragment = 0;
-    
-  switch (li) {
-    case LI_NORMAL_DT_WITH_CHECKSUM      :
-      tpdu_nr = pd[offset + P_TPDU_NR_234];
-      if ( tpdu_nr & 0x80 )
-	tpdu_nr = tpdu_nr & 0x7F;
-      else
-	fragment = 1;
-      code = pd[offset + P_VAR_PART_NDT];
-      if (code == VP_CHECKSUM)
-	checksum = EXTRACT_SHORT(&pd[offset + P_VAR_PART_NDT + 2]);
-      else
-	return -1;
-      break;
-    case LI_NORMAL_DT_WITHOUT_CHECKSUM   :
-      tpdu_nr = pd[offset + P_TPDU_NR_234];
-      if ( tpdu_nr & 0x80 )
-	tpdu_nr = tpdu_nr & 0x7F;
-      else
-	fragment = 1;
-      break;
-    case LI_EXTENDED_DT_WITH_CHECKSUM    :
-      tpdu_nr = EXTRACT_LONG(&pd[offset + P_TPDU_NR_234]);
-      if ( tpdu_nr & 0x80000000 )
-	tpdu_nr = tpdu_nr & 0x7FFFFFFF;
-      else
-	fragment = 1;
-      code = pd[offset + P_VAR_PART_EDT];
-      if (code == VP_CHECKSUM)
-	checksum = EXTRACT_SHORT(&pd[offset + P_VAR_PART_EDT + 2]);
-      else
-	return -1;
-      break;
-    case LI_EXTENDED_DT_WITHOUT_CHECKSUM :
-      tpdu_nr = EXTRACT_LONG(&pd[offset + P_TPDU_NR_234]);
-      if ( tpdu_nr & 0x80000000 )
-	tpdu_nr = tpdu_nr & 0x7FFFFFFF;
-      else
-	fragment = 1;
-      break;
-    case LI_NORMAL_DT_CLASS_01           :
-      tpdu_nr = pd[offset + P_TPDU_NR_0_1];
-      if ( tpdu_nr & 0x80 )
-	tpdu_nr = tpdu_nr & 0x7F;
-      else
-	fragment = 1;      
-      break;
-    default : /* bad TPDU */
-      return -1;
-      /*NOTREACHED*/
-      break;
-  }
-
-  if (check_col(fd, COL_INFO))
-    col_append_fstr(fd, COL_INFO, "DT TPDU (%d) dst-ref: 0x%04x %s", 
-		 tpdu_nr,
-		 dst_ref,
-		 (fragment)? "(fragment)" : "");
-
-  if (tree) {
-    ti = proto_tree_add_item(tree, proto_cotp, offset, li + 1, NULL);
-    cotp_tree = proto_item_add_subtree(ti, ett_cotp);
-    proto_tree_add_text(cotp_tree, offset,      1,
-			"Length indicator: %d", li);
-    proto_tree_add_text(cotp_tree, offset +  1, 1, 
-			"TPDU code: 0x%x (DT)", tpdu); 
-
-    if (li != LI_NORMAL_DT_CLASS_01)
-      proto_tree_add_text(cotp_tree, offset +  2, 2, 
-			  "Destination reference: 0x%04x", dst_ref);
 
-    switch (li) {
-      case LI_NORMAL_DT_WITH_CHECKSUM      :
-	proto_tree_add_text(cotp_tree, offset +  4, 1, 
-			    "TPDU number: 0x%02x (%s)", 
-			    tpdu_nr,
-			    (fragment)? "fragment":"complete");
-	proto_tree_add_text(cotp_tree, 
-			    offset +  P_VAR_PART_NDT, 1, 
-			    "Parameter code: 0x%02x (checksum)", code);
-	proto_tree_add_text(cotp_tree, 
-			    offset +  P_VAR_PART_NDT + 1, 1, 
-			    "Parameter length: %u", length);
-	proto_tree_add_text(cotp_tree, 
-			    offset +  P_VAR_PART_NDT + 2, length, 
-			    "Checksum: 0x%04x", checksum);
-	break;
-      case LI_NORMAL_DT_WITHOUT_CHECKSUM   :
-	proto_tree_add_text(cotp_tree, offset +  4, 1, 
-			    "TPDU number: 0x%02x (%s)", 
-			    tpdu_nr,
-			    (fragment)? "fragment":"complete");
-	break;
-      case LI_EXTENDED_DT_WITH_CHECKSUM    :
-	proto_tree_add_text(cotp_tree, offset +  4, 4, 
-			    "TPDU number: 0x%08x (%s)", 
-			    tpdu_nr,
-			    (fragment)? "fragment":"complete");
-	proto_tree_add_text(cotp_tree, 
-			    offset +  P_VAR_PART_EDT, 1, 
-			    "Parameter code: 0x%02x (checksum)", code);
-	proto_tree_add_text(cotp_tree, 
-			    offset +  P_VAR_PART_EDT + 1, 1, 
-			    "Parameter length: %u", length);
-	proto_tree_add_text(cotp_tree, 
-			    offset +  P_VAR_PART_EDT + 2, length, 
-			    "Checksum: 0x%04x", checksum);
-	break;
-      case LI_EXTENDED_DT_WITHOUT_CHECKSUM :
-	proto_tree_add_text(cotp_tree, offset +  4, 4, 
-			    "TPDU number: 0x%08x (%s)", 
-			    tpdu_nr,
-			    (fragment)? "fragment":"complete");
-	break;
-      case LI_NORMAL_DT_CLASS_01           :
-	proto_tree_add_text(cotp_tree, offset +  2, 1, 
-			    "TPDU number: 0x%02x (%s)", 
-			    tpdu_nr,
-			    (fragment)? "fragment":"complete");
-	break;
+gchar *print_system_id( const u_char *buffer, int length ) {
+  int           tmp;
+  u_char       *cur; 
+  static gchar  str[MAX_SYSTEMID_LEN * 3 + 5]; /* Don't trust exact matching */  
+ 
+  if ( ( length <= 0 ) || ( length > MAX_SYSTEMID_LEN ) ) {
+    sprintf( str, "<Invalid length of SYSTEM ID>");
+    return( str );
+  }  
+ 
+  cur = str;
+  if ( ( 6 == length ) || ( 7 == length ) ) { /* Special case, print as MAC */
+    cur += sprintf(str, "[%02x:%02x:%02x_%02x:%02x:%02x]", buffer[0], buffer[1],
+                    buffer[2], buffer[3], buffer[4], buffer[5] );
+    if ( 7 == length ) {
+      sprintf( cur, "-%02x", buffer[6] );
     }
-  } /* tree */
-
-  offset += li + 1;
-  if (uses_inactive_subset){
-	dissect_h1(pd, offset, fd, tree);
-	return TRUE;
-	}
+  }
   else {
-	dissect_data(pd, offset, fd, tree);
-	return FALSE;
-	}
-} /* osi_decode_DT */
-
-static int osi_decode_ED(const u_char *pd, int offset, 
-			 frame_data *fd, proto_tree *tree)
-{
-  proto_tree *cotp_tree;
-  proto_item *ti;
-  u_int    tpdu_nr ;
-  u_short  checksum = 0;
-  u_char   code = 0, length = 0;
-
-  /* ED TPDUs are never fragmented */
-
-  switch (li) {
-    case LI_NORMAL_DT_WITH_CHECKSUM      :
-      tpdu_nr = pd[offset + P_TPDU_NR_234];
-      if ( tpdu_nr & 0x80 )
-	tpdu_nr = tpdu_nr & 0x7F;
-      else
-	return -1;
-      code = pd[offset + P_VAR_PART_NDT];
-      length = pd[offset + P_VAR_PART_NDT + 1];
-      if (code == VP_CHECKSUM)
-	checksum = EXTRACT_SHORT(&pd[offset + P_VAR_PART_NDT + 2]);
-      else
-	return -1;
-      break;
-    case LI_NORMAL_DT_WITHOUT_CHECKSUM   :
-      tpdu_nr = pd[offset + P_TPDU_NR_234];
-      if ( tpdu_nr & 0x80 )
-	tpdu_nr = tpdu_nr & 0x7F;
-      else
-	return -1;
-      break;
-    case LI_EXTENDED_DT_WITH_CHECKSUM    :
-      tpdu_nr = EXTRACT_LONG(&pd[offset + P_TPDU_NR_234]);
-      if ( tpdu_nr & 0x80000000 )
-	tpdu_nr = tpdu_nr & 0x7FFFFFFF;
-      else
-	return -1;
-      code = pd[offset + P_VAR_PART_EDT];
-      length = pd[offset + P_VAR_PART_EDT + 1];
-      if (code == VP_CHECKSUM)
-	checksum = EXTRACT_SHORT(&pd[offset + P_VAR_PART_EDT + 2]);
-      else
-	return -1;
-      break;
-    case LI_EXTENDED_DT_WITHOUT_CHECKSUM :
-      tpdu_nr = EXTRACT_LONG(&pd[offset + P_TPDU_NR_234]);
-      if ( tpdu_nr & 0x80000000 )
-	tpdu_nr = tpdu_nr & 0x7FFFFFFF;
-      else
-	return -1;
-      break;
-    default : /* bad TPDU */
-      return -1;
-      /*NOTREACHED*/
-      break;
-  } /* li */
-
-  if (check_col(fd, COL_INFO))
-    col_append_fstr(fd, COL_INFO, "ED TPDU (%d) dst-ref: 0x%04x", 
-		 tpdu_nr, dst_ref);
-
-  if (tree) {
-    ti = proto_tree_add_item(tree, proto_cotp, offset, li + 1, NULL);
-    cotp_tree = proto_item_add_subtree(ti, ett_cotp);
-    proto_tree_add_text(cotp_tree, offset,      1,
-			"Length indicator: %d", li);
-    proto_tree_add_text(cotp_tree, offset +  1, 1, 
-			"TPDU code: 0x%x (ED)", tpdu); 
-    proto_tree_add_text(cotp_tree, offset +  2, 2, 
-			"Destination reference: 0x%04x", dst_ref);
-
-    switch (li) {
-      case LI_NORMAL_DT_WITH_CHECKSUM      :
-	proto_tree_add_text(cotp_tree, offset +  4, 1, 
-			    "TPDU number: 0x%02x", tpdu_nr);	
-	proto_tree_add_text(cotp_tree, 
-			    offset +  P_VAR_PART_NDT, 1, 
-			    "Parameter code: 0x%02x (checksum)", code);
-	proto_tree_add_text(cotp_tree, 
-			    offset +  P_VAR_PART_NDT + 1, 1, 
-			    "Parameter length: %u", length);
-	proto_tree_add_text(cotp_tree, 
-			    offset +  P_VAR_PART_NDT + 2, length, 
-			    "Checksum: 0x%04x", checksum);
-	break;
-      case LI_NORMAL_DT_WITHOUT_CHECKSUM   :
-	proto_tree_add_text(cotp_tree, offset +  4, 1, 
-			    "TPDU number: 0x%02x", tpdu_nr);
-	break;
-      case LI_EXTENDED_DT_WITH_CHECKSUM    :
-	proto_tree_add_text(cotp_tree, offset +  4, 4, 
-			    "TPDU number: 0x%02x", tpdu_nr);	
-	proto_tree_add_text(cotp_tree, 
-			    offset +  P_VAR_PART_EDT, 1, 
-			    "Parameter code: 0x%02x (checksum)", code);
-	proto_tree_add_text(cotp_tree, 
-			    offset +  P_VAR_PART_EDT + 1, 1, 
-			    "Parameter length: %u", length);
-	proto_tree_add_text(cotp_tree, 
-			    offset +  P_VAR_PART_EDT + 2, length, 
-			    "Checksum: 0x%04x", checksum);
-	break;
-      case LI_EXTENDED_DT_WITHOUT_CHECKSUM :
-	proto_tree_add_text(cotp_tree, offset +  4, 4, 
-			    "TPDU number: 0x%02x", tpdu_nr);
-	break;
+    tmp = 0;
+    while ( tmp < length / 4 ) { /* 16 / 4 == 4 > four Octets left to print */
+      cur += sprintf( str, "%02x%02x%02x%02x.", buffer[tmp++], buffer[tmp++],
+                      buffer[tmp++], buffer[tmp++] );
     }
-  } /* tree */
-
-  offset += li + 1;
-  dissect_data(pd, offset, fd, tree);
-
-  return pi.captured_len;	/* we dissected all of the containing PDU */
-
-} /* osi_decode_ED */
-
-static int osi_decode_RJ(const u_char *pd, int offset, 
-			 frame_data *fd, proto_tree *tree)
-{
-  proto_tree *cotp_tree;
-  proto_item *ti;
-  u_int    tpdu_nr ;
-  u_short  credit = 0;
-
-  switch(li) {
-    case LI_NORMAL_RJ   :
-      tpdu_nr = pd[offset + P_TPDU_NR_234];
-      break;
-    case LI_EXTENDED_RJ :
-      tpdu_nr = EXTRACT_LONG(&pd[offset + P_TPDU_NR_234]);
-      credit = EXTRACT_SHORT(&pd[offset + P_CDT_IN_RJ]);
-      break;
-    default :
-      return -1;
-      /*NOTREACHED*/
-      break;
-  }
-
-  if (check_col(fd, COL_INFO))
-    col_append_fstr(fd, COL_INFO, "RJ TPDU (%d) dst-ref: 0x%04x", 
-		 tpdu_nr, dst_ref);
-
-  if (tree) {
-    ti = proto_tree_add_item(tree, proto_cotp, offset, li + 1, NULL);
-    cotp_tree = proto_item_add_subtree(ti, ett_cotp);
-    proto_tree_add_text(cotp_tree, offset,      1,
-			"Length indicator: %d", li);
-    proto_tree_add_text(cotp_tree, offset +  1, 1, 
-			"TPDU code: 0x%x (RJ)", tpdu); 
-    if (li == LI_NORMAL_RJ)
-      proto_tree_add_text(cotp_tree, offset +  1, 1, 
-			  "Credit: %d", cdt);
-    proto_tree_add_text(cotp_tree, offset +  2, 2, 
-			"Destination reference: 0x%04x", dst_ref);
-    if (li == LI_NORMAL_RJ)
-      proto_tree_add_text(cotp_tree, offset +  4, 1, 
-			  "Your TPDU number: 0x%02x", tpdu_nr);
-    else {
-      proto_tree_add_text(cotp_tree, offset +  4, 4, 
-			  "Your TPDU number: 0x%02x", tpdu_nr);
-      proto_tree_add_text(cotp_tree, offset +  8, 2, 
-			  "Credit: 0x%02x", credit);
+    if ( 1 == tmp ) {   /* Special case for Designated IS */
+      sprintf( --cur, "-%02x", buffer[tmp] );
     }
-  }
-
-  offset += li + 1;
-
-  return offset;
-
-} /* osi_decode_RJ */
-
-#define MAX_TSAP_LEN	32
-
-static gchar *print_tsap(const u_char *tsap, int length)
-{
-
-  static gchar  str[3][MAX_TSAP_LEN * 2 + 1];
-  static gchar *cur;
-  gchar tmp[3];
-  gboolean allprintable;
-  int i;
-
-  if (cur == &str[0][0]) {
-    cur = &str[1][0];
-  } else if (cur == &str[1][0]) {  
-    cur = &str[2][0];
-  } else {  
-    cur = &str[0][0];
-  }
-
-
-  cur[0] = '\0';
-  if (length <= 0 || length > MAX_TSAP_LEN) 
-    sprintf(cur, "<unsupported TSAP length>");
-  else {    
-    allprintable=TRUE;
-    for (i=0;i<length;i++) {
-	if (!isprint(tsap[i])) { /* if any byte is not printable */
-	  allprintable=FALSE;    /* switch to hexdump */
-	  break;
-	  }	 
-	}
-    if (!allprintable){
-      strcat(cur,"0x");
+    else {
+      for ( ; tmp < length; ) {  /* print the rest without dot */
+        cur += sprintf( cur, "%02x", buffer[tmp++] );
       }
-    while (length != 0) {
-      if (allprintable)
-	sprintf(tmp, "%c", *tsap ++);
-      else
-	sprintf(tmp, "%02x", *tsap ++);
-      strcat(cur, tmp);
-      length --;
     }
   }
-  return cur;
-
-} /* print_tsap */
-
-static int osi_decode_CC(const u_char *pd, int offset, 
-			 frame_data *fd, proto_tree *tree)
-{
-
-  /* CC & CR decoding in the same function */
-
-  proto_tree *cotp_tree = NULL;
-  proto_item *ti;
-  u_short src_ref, checksum;
-  u_char  class_option, code, length;
-  u_int   i = 0;
-
-  src_ref = EXTRACT_SHORT(&pd[offset + P_SRC_REF]);
-  class_option = (pd[offset + P_CLASS_OPTION] >> 4 ) & 0x0F;
-  if (class_option > 4)
-    return -1;
-
-  if (check_col(fd, COL_INFO))
-    col_append_fstr(fd, COL_INFO, "%s TPDU src-ref: 0x%04x dst-ref: 0x%04x",
-		 (tpdu == CR_TPDU) ? "CR" : "CC",
-		 src_ref,
-		 dst_ref);
-
-  if (tree) {
-    ti = proto_tree_add_item(tree, proto_cotp, offset, li + 1, NULL);
-    cotp_tree = proto_item_add_subtree(ti, ett_cotp);
-    proto_tree_add_text(cotp_tree, offset,      1,
-			"Length indicator: %d", li);
-    proto_tree_add_text(cotp_tree, offset +  1, 1, 
-			"TPDU code: 0x%x (%s)", tpdu,
-			(tpdu == CR_TPDU) ? "CR" : "CC"); 
-    proto_tree_add_text(cotp_tree, offset +  2, 2, 
-			"Destination reference: 0x%04x", dst_ref);
-    proto_tree_add_text(cotp_tree, offset +  4, 2, 
-			"Source reference: 0x%04x", src_ref);
-    proto_tree_add_text(cotp_tree, offset +  6, 1, 
-			"Class option: 0x%02x", class_option);
-  }
-
-  if (tree)
-    while(li > P_VAR_PART_CC + i - 1) {
-      
-      u_char  c1;
-      u_short s, s1,s2,s3,s4;
-      u_int   t1,t2,t3,t4;
-      
-      switch( (code = pd[offset + P_VAR_PART_CC + i]) )	{
-	case VP_CHECKSUM :
-	  length   = pd[offset + P_VAR_PART_CC + i + 1];
-	  checksum = EXTRACT_SHORT(&pd[offset + P_VAR_PART_CC + i + 2]);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i, 1, 
-			      "Parameter code: 0x%02x (checksum)", code);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 1, 1, 
-			      "Parameter length: %u", length);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 2, length, 
-			      "Checksum: 0x%04x", checksum);
-	  i += length + 2;
-	  break;
-	case VP_SRC_TSAP    :
-	  length = pd[offset + P_VAR_PART_CC + i + 1];
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i, 1, 
-			      "Parameter code: 0x%02x (src-tsap)", code);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 1, 1, 
-			      "Parameter length: %u", length);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 2, length, 
-			      "Calling TSAP: %s", 
-			      print_tsap(&pd[offset + P_VAR_PART_CC + i + 2],
-					 length));
-	  i += length + 2;
-	  break;
-	case VP_DST_TSAP    :
-	  length = pd[offset + P_VAR_PART_CC + i + 1];
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i, 1, 
-			      "Parameter code: 0x%02x (dst-tsap)", code);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 1, 1, 
-			      "Parameter length: %u", length);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 2, length, 
-			      "Called TSAP: %s", 
-			      print_tsap(&pd[offset + P_VAR_PART_CC + i + 2],
-					 length));
-	  i += length + 2;
-	  break;
-	case VP_TPDU_SIZE   :
-	  length = pd[offset + P_VAR_PART_CC + i + 1];
-	  c1 = pd[offset + P_VAR_PART_CC + i + 2] & 0x0F;
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i, 1, 
-			      "Parameter code: 0x%02x (tpdu-size)", code);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 1, 1, 
-			      "Parameter length: %u", length);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 2, length, 
-			      "TPDU size: %u", 2 << c1);
-	  i += length + 2;
-	  break;
-	case VP_OPT_SEL     :
-	  length = pd[offset + P_VAR_PART_CC + i + 1];
-	  c1 = pd[offset + P_VAR_PART_CC + i + 2] & 0x0F;
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i, 1, 
-			      "Parameter code: 0x%02x (options)", code);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 1, 1, 
-			      "Parameter length: %u", length);
-	  if (class_option == 1) {
-	    if (c1 & 0x8)
-	      proto_tree_add_text(cotp_tree, 
-				  offset +  P_VAR_PART_CC + i + 2, 1,
-				  "Use of network expedited data");
-	    else
-	      proto_tree_add_text(cotp_tree, 
-				  offset +  P_VAR_PART_CC + i + 2, 1,
-				  "Non use of network expedited data");
-	    if (c1 & 0x4)
-	      proto_tree_add_text(cotp_tree, 
-				  offset +  P_VAR_PART_CC + i + 2, 1,
-				  "Use of Receipt confirmation");
-	    else
-	      proto_tree_add_text(cotp_tree, 
-				  offset +  P_VAR_PART_CC + i + 2, 1,
-				  "Use of explicit AK variant");
-	  } else if (class_option == 4) {
-	    if (c1 & 0x2)
-	      proto_tree_add_text(cotp_tree, 
-				  offset +  P_VAR_PART_CC + i + 2, 1,
-				  "Use 16 bit checksum ");
-	    else
-	      proto_tree_add_text(cotp_tree, 
-				  offset +  P_VAR_PART_CC + i + 2, 1,
-				  "Non-use 16 bit checksum in class 4");
-	  }
-	  if (c1 & 0x1)
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_CC + i + 2, 1,
-				"Use of transport expedited data transfer\n");
-	  else
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_CC + i + 2, 1,
-				"Non-use of transport expedited data transfer");
-	  i += length + 2;
-	  break;
-	case VP_ACK_TIME    :
-	  length = pd[offset + P_VAR_PART_CC + i + 1];
-	  s = EXTRACT_SHORT(&pd[offset + P_VAR_PART_CC + i + 2]);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i, 1, 
-			      "Parameter code: 0x%02x (ack time)", code);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 1, 1, 
-			      "Parameter length: %u", length);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 2, length, 
-			      "Ack time (ms): %u", s);
-	  i += length + 2;
-	  break;
-	case VP_THROUGHPUT  :
-	  length = pd[offset + P_VAR_PART_CC + i + 1];
-	  t1 = EXTRACT_LONG(&pd[offset + P_VAR_PART_CC + i + 1]);
-	  t2 = EXTRACT_LONG(&pd[offset + P_VAR_PART_CC + i + 4]);
-	  t3 = EXTRACT_LONG(&pd[offset + P_VAR_PART_CC + i + 7]);
-	  t4 = EXTRACT_LONG(&pd[offset + P_VAR_PART_CC + i + 10]);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i, 1, 
-			      "Parameter code: 0x%02x (throughput)", code);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 1, 1, 
-			      "Parameter length: %u", length);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 2, 4, 
-			      "Target value / calling-called: %u o/s", t1);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 6, 4, 
-			      "Minimum / calling-called: %u o/s", t2);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 10, 4, 
-			      "Target value / called-calling: %u o/s", t3);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 14, 4, 
-			      "Minimum / called-calling: %u o/s", t4);
-	  i += length + 2;
-	  break;
-        case VP_TRANSIT_DEL :
-	  length = pd[offset + P_VAR_PART_CC + i + 1];
-	  s1 = EXTRACT_SHORT(&pd[offset + P_VAR_PART_CC + i + 2]);
-	  s2 = EXTRACT_SHORT(&pd[offset + P_VAR_PART_CC + i + 4]);
-	  s3 = EXTRACT_SHORT(&pd[offset + P_VAR_PART_CC + i + 6]);
-	  s4 = EXTRACT_SHORT(&pd[offset + P_VAR_PART_CC + i + 8]);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i, 1, 
-			      "Parameter code: 0x%02x (transit delay)", code);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 1, 1, 
-			      "Parameter length: %u", length);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 2, 2, 
-			      "Target value / calling-called: %u ms", s1);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 4, 2, 
-			      "Minimum / calling-called: %u ms", s2);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 6, 2, 
-			      "Target value / called-calling: %u ms", s3);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 8, 2, 
-			      "Minimum / called-calling: %u ms", s4);
-	  i += length + 2;
-	  break;
-	case VP_PRIORITY    :
-	  length = pd[offset + P_VAR_PART_CC + i + 1];
-	  s = EXTRACT_SHORT(&pd[offset + P_VAR_PART_CC + i + 2]);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i, 1, 
-			      "Parameter code: 0x%02x (priority)", code);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 1, 1, 
-			      "Parameter length: %u", length);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 2, length,
-			      "Priority: %u", s);
-	  i += length + 2;
-	  break;
-	
-	case VP_VERSION_NR  :
-	  length = pd[offset + P_VAR_PART_CC + i + 1];
-	  c1 = pd[offset + P_VAR_PART_CC + i + 2];
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i, 1, 
-			      "Parameter code: 0x%02x (version)", code);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 1, 1, 
-			      "Parameter length: %u", length);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 2, length,
-			      "Version: %u", c1);
-	  i += length + 2;
-	  break;
-
-	case VP_REASSIGNMENT: 	  /* todo */
-	case VP_RES_ERROR   :
-	case VP_PROTECTION  :
-	case VP_PROTO_CLASS :
-	default             :	  /* no decoding */
-	  length = pd[offset + P_VAR_PART_CC + i + 1];
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 0, 1, 
-			      "Parameter code: 0x%02x", code);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 1, 1, 
-			      "Parameter length: %u", length);
-	  proto_tree_add_text(cotp_tree, 
-			      offset +  P_VAR_PART_CC + i + 2, length, 
-			      "Parameter value: <not shown>");
-	  i += length + 2;
-	  break; 
-      }
-    } /* while */
-
-  offset += li + 1;
-  dissect_data(pd, offset, fd, tree);
-
-  return pi.captured_len;	/* we dissected all of the containing PDU */
-
-} /* osi_decode_CC */
+  return( str );
+}
 
-static int osi_decode_DC(const u_char *pd, int offset, 
-			 frame_data *fd, proto_tree *tree)
+gchar *print_area(const u_char *buffer, int length)
 {
-  proto_tree *cotp_tree;
-  proto_item *ti;
-  u_short src_ref, checksum = 0;
-  u_char  length = 0, code = 0;
-
-  if (li > LI_MAX_DC) 
-    return -1;
-
-  src_ref = EXTRACT_SHORT(&pd[offset + P_SRC_REF]);
-
-  switch(li) {
-    case LI_DC_WITHOUT_CHECKSUM :
-      break;
-    case LI_DC_WITH_CHECKSUM :
-      if ((code = pd[offset + P_VAR_PART_DC]) != VP_CHECKSUM) 
-	return -1;
-      length   = pd[offset + P_VAR_PART_DC + 1];
-      checksum = EXTRACT_SHORT(&pd[offset + P_VAR_PART_DC + 2]);
-      break;
-    default :
-      return -1;
-      /*NOTREACHED*/
-      break;
-  } /* li */
+  /* to do : all real area decoding now: NET is assumed if id len is 1 more byte
+   * and take away all these stupid resource consuming local statics
+   */
+  
+  static gchar  str[MAX_AREA_LEN * 3 + 20]; /* reserve space for nice layout */
+  gchar *cur;
+  u_int  tmp  = 0;
 
-  if (check_col(fd, COL_INFO))
-    col_append_fstr(fd, COL_INFO, "DC TPDU src-ref: 0x%04x dst-ref: 0x%04x", 
-		 src_ref,
-		 dst_ref);
+  cur = str;
 
-  if (tree) {
-    ti = proto_tree_add_item(tree, proto_cotp, offset, li + 1, NULL);
-    cotp_tree = proto_item_add_subtree(ti, ett_cotp);
-    proto_tree_add_text(cotp_tree, offset,      1,
-			"Length indicator: %d", li);
-    proto_tree_add_text(cotp_tree, offset +  1, 1, 
-			"TPDU code: 0x%x (DC)", tpdu); 
-    proto_tree_add_text(cotp_tree, offset +  2, 2, 
-			"Destination reference: 0x%04x", dst_ref);
-    proto_tree_add_text(cotp_tree, offset +  4, 2, 
-			"Source reference: 0x%04x", src_ref);
-    if (code) {
-      proto_tree_add_text(cotp_tree, 
-			  offset +  P_VAR_PART_DC + 0, 1, 
-			  "Parameter code: 0x%02x (checksum)", code);
-      proto_tree_add_text(cotp_tree, 
-			  offset +  P_VAR_PART_DC + 1, 1, 
-			  "Parameter length: %u", length);
-      proto_tree_add_text(cotp_tree, 
-			  offset +  P_VAR_PART_DC + 2, 2, 
-			  "Checksum: 0x%04x", checksum);
-    }
+  if (length <= 0 || length > MAX_AREA_LEN) {
+    sprintf( str, "<Invalid length of AREA>");
+    return( str );
   }
-
-  offset += li + 1;
-
-  return offset;
-
-} /* osi_decode_DC */
-
-static int osi_decode_AK(const u_char *pd, int offset, 
-			 frame_data *fd, proto_tree *tree)
-{
-  proto_tree *cotp_tree = NULL;
-  proto_item *ti;
-  u_int      tpdu_nr,i =0, r_lower_window_edge ;
-  u_short    cdt_in_ak;
-  u_short    checksum, seq_nr, r_seq_nr, r_cdt;
-  u_char     code, length;
-
-  if (li > LI_MAX_AK) 
-    return -1;
-
-  if (!is_LI_NORMAL_AK(li)) {
-    tpdu_nr = pd[offset + P_TPDU_NR_234];
-
-    if (check_col(fd, COL_INFO))
-      col_append_fstr(fd, COL_INFO, "AK TPDU (%d) dst-ref: 0x%04x", 
-		   tpdu_nr, dst_ref);
-    
-    if (tree) {
-      ti = proto_tree_add_item(tree, proto_cotp, offset, li + 1, NULL);
-      cotp_tree = proto_item_add_subtree(ti, ett_cotp);
-      proto_tree_add_text(cotp_tree, offset,      1,
-			  "Length indicator: %d", li);
-      proto_tree_add_text(cotp_tree, offset +  1, 1, 
-			  "TPDU code: 0x%x (AK)", tpdu); 
-      proto_tree_add_text(cotp_tree, offset +  1, 1, 
-			  "Credit: %d", cdt);
-      proto_tree_add_text(cotp_tree, offset +  2, 2, 
-			  "Destination reference: 0x%04x", dst_ref);
-      proto_tree_add_text(cotp_tree, offset +  4, 1, 
-			  "Your TPDU number: 0x%02x", tpdu_nr);
-    }
-
-    while(li > P_VAR_PART_NAK + i - 1) {
-      switch( (code = pd[offset + P_VAR_PART_NAK + i]) ) {
-        case VP_CHECKSUM :
-	  length   = pd[offset + P_VAR_PART_NAK + i + 1];
-	  checksum = EXTRACT_SHORT(&pd[offset + P_VAR_PART_NAK + i + 2]);
-	  if (tree) {
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_NAK + i + 0, 1, 
-				"Parameter code: 0x%02x (checksum)", code);
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_NAK + i + 1, 1, 
-				"Parameter length: %u", length);
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_NAK + i + 2, 2, 
-				"Checksum: 0x%04x", checksum);
-	  }
-	  i += length + 2;
-	  break;
-        case VP_FLOW_CNTL :
-	  length = pd[offset + P_VAR_PART_NAK + i + 1];
-	  r_lower_window_edge = 
-	    EXTRACT_LONG(&pd[offset + P_VAR_PART_NAK + i + 2]);
-	  r_seq_nr = EXTRACT_SHORT(&pd[offset + P_VAR_PART_NAK + i + 6]);
-	  r_cdt = EXTRACT_SHORT(&pd[offset + P_VAR_PART_NAK + i + 8]);
-	  if (tree) {
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_NAK + i + 0, 1, 
-				"Parameter code: 0x%02x (flow control)", 
-				code);
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_NAK + i + 1, 1, 
-				"Parameter length: %u", length);
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_NAK + i + 2, 4, 
-				"Lower window edge: 0x%08x", 
-				r_lower_window_edge);
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_NAK + i + 6, 2, 
-				"Sequence number: 0x%04x", 
-				r_seq_nr);
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_NAK + i + 8, 2, 
-				"Credit: 0x%04x", 
-				r_cdt);
-	  }
-	  i += length + 2;
-	  break;
-        case VP_SEQ_NR :
-	  length = pd[offset + P_VAR_PART_NAK + i + 1];
-	  seq_nr = EXTRACT_SHORT(&pd[offset + P_VAR_PART_NAK + i + 2]);
-	  if (tree) {
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_NAK + i + 0, 1, 
-				"Parameter code: 0x%02x (seq number)", code);
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_NAK + i + 1, 1, 
-				"Parameter length: %u", length);
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_NAK + i + 2, 2, 
-				"Sequence number: 0x%04x", seq_nr);
-	  }
-	  i += length + 2;
-	  break;
-        default :
-	  length = pd[offset + P_VAR_PART_NAK + i + 1];
-	  if (tree) {
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_NAK + i + 0, 1, 
-				"Parameter code: 0x%02x (unknown)", code);
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_NAK + i + 1, 1, 
-				"Parameter length: %u", length);
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_NAK + i + 2, length, 
-				"Parameter value: <not shown>");
-	  }
-	  i += length + 2;
-	  break;
-      } /* code */
-    }
-  } else { /* extended format */
-    
-    tpdu_nr   = EXTRACT_LONG(&pd[offset + P_TPDU_NR_234]);
-    cdt_in_ak = EXTRACT_SHORT(&pd[offset + P_CDT_IN_AK]);
-
-    if (check_col(fd, COL_INFO))
-      col_append_fstr(fd, COL_INFO, "AK TPDU (%d) dst-ref: 0x%04x", 
-		   tpdu_nr, dst_ref);
-    
-    if (tree) {
-      ti = proto_tree_add_item(tree, proto_cotp, offset, li + 1, NULL);
-      cotp_tree = proto_item_add_subtree(ti, ett_cotp);
-      proto_tree_add_text(cotp_tree, offset,      1,
-			  "Length indicator: %d", li);
-      proto_tree_add_text(cotp_tree, offset +  1, 1, 
-			  "TPDU code: 0x%x (AK)", tpdu); 
-      proto_tree_add_text(cotp_tree, offset +  2, 2, 
-			  "Destination reference: 0x%04x", dst_ref);
-      proto_tree_add_text(cotp_tree, offset +  4, 4, 
-			  "Your TPDU number: 0x%08x", tpdu_nr);
-      proto_tree_add_text(cotp_tree, offset +  8, 2, 
-			  "Credit: 0x%04x", cdt_in_ak);
+  
+  if ( (  ( NSAP_IDI_ISODCC          == *buffer )      
+       || ( NSAP_IDI_GOSIP2          == *buffer )
+       )
+       && 
+       (  ( RFC1237_FULLAREA_LEN     ==  length ) 
+       || ( RFC1237_FULLAREA_LEN + 1 ==  length )
+       ) 
+     ) {    /* AFI is good and length is long enough  */
+  
+    if ( length > RFC1237_FULLAREA_LEN + 1 ) {  /* Special Case Designated IS */
+      sprintf( str, "<Invalid length of AREA for DCC / GOSIP AFI>");
+      return( str );
     }
-    
-    while(li > P_VAR_PART_EAK + i - 1) {
-      switch( (code = pd[offset + P_VAR_PART_EAK + i]) ) {
-        case VP_CHECKSUM :
-	  length   = pd[offset + P_VAR_PART_EAK + i + 1];
-	  checksum = EXTRACT_SHORT(&pd[offset + P_VAR_PART_EAK + i + 2]);
-	  if (tree) {
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_EAK + i + 0, 1, 
-				"Parameter code: 0x%02x (checksum)", code);
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_EAK + i + 1, 1, 
-				"Parameter length: %u", length);
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_EAK + i + 2, 2, 
-				"Checksum: 0x%04x", checksum);
-	  }
-	  i += length + 2;
-	  break;
-        case VP_FLOW_CNTL :
-	  length   = pd[offset + P_VAR_PART_EAK + i + 1];
-	  r_lower_window_edge = 
-	    EXTRACT_LONG(&pd[offset + P_VAR_PART_EAK + i + 2]);
-	  r_seq_nr = EXTRACT_SHORT(&pd[offset + P_VAR_PART_EAK + i + 6]);
-	  r_cdt = EXTRACT_SHORT(&pd[offset + P_VAR_PART_EAK + i + 8]);
-	  if (tree) {
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_EAK + i + 0, 1, 
-				"Parameter code: 0x%02x (flow control)",
-				code);
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_EAK + i + 1, 1, 
-				"Parameter length: %u", length);
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_EAK + i + 2, 4, 
-				"Lower window edge: 0x%08x", 
-				r_lower_window_edge);
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_EAK + i + 6, 2, 
-				"Sequence number: 0x%04x", 
-				r_seq_nr);
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_EAK + i + 8, 2, 
-				"Credit: 0x%04x", 
-				r_cdt);
-	  }
-	  i += length + 2;
-	  break;
-        case VP_SEQ_NR :
-	  length   = pd[offset + P_VAR_PART_EAK + i + 1];
-	  seq_nr = EXTRACT_SHORT(&pd[offset + P_VAR_PART_EAK + i + 2]);
-	  if (tree) {
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_EAK + i + 0, 1, 
-				"Parameter code: 0x%02x (seq number)", code);
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_EAK + i + 1, 1, 
-				"Parameter length: %u", length);
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_EAK + i + 2, 2, 
-				"Sequence number: 0x%04x", seq_nr);
-	  }
-	  i += length + 2;
-	  break;
-        default :
-	  length   = pd[offset + P_VAR_PART_EAK + i + 1];
-	  if (tree) {
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_EAK + i + 0, 1, 
-				"Parameter code: 0x%02x (unknown)", code);
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_EAK + i + 1, 1, 
-				"Parameter length: %u", length);
-	    proto_tree_add_text(cotp_tree, 
-				offset +  P_VAR_PART_EAK + i + 2, length, 
-				"Parameter value: <not shown>");
-	  }
-	  i += length + 2;
-	  break;
-      } /* code */
+ 
+    cur += sprintf( cur, "[%02x|%02x:%02x][%02x|%02x:%02x:%02x|%02x:%02x]", 
+                    buffer[0], buffer[1], buffer[2], buffer[3], buffer[4], 
+                    buffer[5], buffer[6], buffer[7], buffer[8] );
+    cur += sprintf( cur, "[%02x:%02x|%02x:%02x]",
+                    buffer[9], buffer[10],  buffer[11], buffer[12] );
+    if ( RFC1237_FULLAREA_LEN + 1 == length ) {
+      sprintf( cur, "-[%02x]", buffer[20] );
     }
-    
-  } /* is_LI_NORMAL_AK */
-
-  offset += li + 1;
-
-  return offset;
-
-} /* osi_decode_AK */
-
-static int osi_decode_EA(const u_char *pd, int offset, 
-			 frame_data *fd, proto_tree *tree)
-{
-  proto_tree *cotp_tree;
-  proto_item *ti;
-  u_int    tpdu_nr ;
-  u_short  checksum = 0;
-  u_char   code = 0;
-  u_char   length = 0;
-
-  if (li > LI_MAX_EA) 
-    return -1;
-
-  switch (li) {
-    case LI_NORMAL_EA_WITH_CHECKSUM      :
-      tpdu_nr = pd[offset + P_TPDU_NR_234];
-      code    = pd[offset + P_VAR_PART_NDT];
-      length  = pd[offset + P_VAR_PART_NDT + 1];
-      if (code != VP_CHECKSUM || length != 1)
-	return -1;
-      checksum = EXTRACT_SHORT(&pd[offset + P_VAR_PART_NDT + 2]);
-      break;
-    case LI_NORMAL_EA_WITHOUT_CHECKSUM   :
-      tpdu_nr = pd[offset + P_TPDU_NR_234];
-      break;
-    case LI_EXTENDED_EA_WITH_CHECKSUM    :
-      tpdu_nr = EXTRACT_LONG(&pd[offset + P_TPDU_NR_234]);
-      code    = pd[offset + P_VAR_PART_EDT];
-      length  = pd[offset + P_VAR_PART_EDT + 1];
-      if (code != VP_CHECKSUM || length != 1)
-	return -1;
-      checksum = EXTRACT_SHORT(&pd[offset + P_VAR_PART_EDT + 2]);
-      break;
-    case LI_EXTENDED_EA_WITHOUT_CHECKSUM :
-      tpdu_nr = EXTRACT_LONG(&pd[offset + P_TPDU_NR_234]);
-      break;
-    default : /* bad TPDU */
-      return -1;
-      /*NOTREACHED*/
-      break;
-  } /* li */
-
-  if (check_col(fd, COL_INFO))
-    col_append_fstr(fd, COL_INFO, 
-		 "EA TPDU (%d) dst-ref: 0x%04x", tpdu_nr, dst_ref);
-
-  if (tree) {
-    ti = proto_tree_add_item(tree, proto_cotp, offset, li + 1, NULL);
-    cotp_tree = proto_item_add_subtree(ti, ett_cotp);
-    proto_tree_add_text(cotp_tree, offset,      1,
-			"Length indicator: %d", li);
-    proto_tree_add_text(cotp_tree, offset +  1, 1, 
-			"TPDU code: 0x%x (EA)", tpdu); 
-    proto_tree_add_text(cotp_tree, offset +  2, 2, 
-			"Destination reference: 0x%04x", dst_ref);
-
-    switch (li) {
-      case LI_NORMAL_EA_WITH_CHECKSUM      :
-	proto_tree_add_text(cotp_tree, offset +  4, 1, 
-			    "Your TPDU number: 0x%02x", tpdu_nr);
-	proto_tree_add_text(cotp_tree, offset +  5, 1, 
-			    "Parameter code: 0x%02x (checksum)", code);
-	proto_tree_add_text(cotp_tree, offset +  6, 1, 
-			    "Parameter length: %u", length);
-	proto_tree_add_text(cotp_tree, offset +  7, 2, 
-			    "Checksum: 0x%04x", checksum);
-	break;
-      case LI_NORMAL_EA_WITHOUT_CHECKSUM   :
-	proto_tree_add_text(cotp_tree, offset +  4, 1, 
-			    "Your TPDU number: 0x%02x", tpdu_nr);
-	break;
-      case LI_EXTENDED_EA_WITH_CHECKSUM    :
-	proto_tree_add_text(cotp_tree, offset +  4, 4, 
-			    "Your TPDU number: 0x%08x", tpdu_nr);
-	proto_tree_add_text(cotp_tree, offset +  8, 1, 
-			    "Parameter code: 0x%02x (checksum)", code);
-	proto_tree_add_text(cotp_tree, offset +  9, 1, 
-			    "Parameter length: %u", length);
-	proto_tree_add_text(cotp_tree, offset +  10, 2, 
-			    "Checksum: 0x%04x", checksum);
-	break;
-      case LI_EXTENDED_EA_WITHOUT_CHECKSUM :
-	proto_tree_add_text(cotp_tree, offset +  4, 4, 
-			    "Your TPDU number: 0x%08x", tpdu_nr);
-	break;
-      default :
-	break;
-    } /* li */
-  } /* tree */
-
-  offset += li + 1;
-
-  return offset;
-
-} /* osi_decode_EA */
-
-static int osi_decode_ER(const u_char *pd, int offset, 
-			 frame_data *fd, proto_tree *tree)
-{
-  proto_tree *cotp_tree;
-  proto_item *ti;
-  u_char *str;
-
-  if (li > LI_MAX_ER) 
-    return -1;
-
-  switch(pd[offset + P_REJECT_ER]) {
-    case 0 :
-      str = "Reason not specified";
-      break;
-    case 1 :
-      str = "Invalid parameter code";
-      break;
-    case 2 :
-      str = "Invalid TPDU type";
-      break;
-    case 3 :
-      str = "Invalid parameter value";
-      break;
-    default:
-      return -1;
-      /*NOTREACHED*/
-      break;
+    return str;
   }
-
-  if (check_col(fd, COL_INFO))
-    col_append_fstr(fd, COL_INFO, "ER TPDU dst-ref: 0x%04x", dst_ref);
-
-  if (tree) {
-    ti = proto_tree_add_item(tree, proto_cotp, offset, li + 1, NULL);
-    cotp_tree = proto_item_add_subtree(ti, ett_cotp);
-    proto_tree_add_text(cotp_tree, offset,      1,
-			"Length indicator: %d", li);
-    proto_tree_add_text(cotp_tree, offset +  1, 1, 
-			"TPDU code: 0x%x (ER)", tpdu); 
-    proto_tree_add_text(cotp_tree, offset +  2, 2, 
-			"Destination reference: 0x%04x", dst_ref);
-    proto_tree_add_text(cotp_tree, offset +  4, 1, 
-			"Reject cause: %s", str);
-  }
-
-  offset += li + 1;
-
-  return offset;
-
-} /* osi_decode_ER */
-
-/* Returns TRUE if we found at least one valid COTP PDU, FALSE
-   otherwise. */
-static gboolean dissect_cotp_internal(const u_char *pd, int offset,
-		  frame_data *fd, proto_tree *tree,
-		  gboolean uses_inactive_subset) 
-{
-  gboolean first_tpdu = TRUE;
-  int new_offset;
-  gboolean found_cotp = FALSE;
-  gboolean subdissector_found = FALSE;
-
-  /* Initialize the COL_INFO field; each of the TPDUs will have its
-     information appended. */
-  if (check_col(fd, COL_INFO))
-    col_add_str(fd, COL_INFO, "");
-
-  while (IS_DATA_IN_FRAME(offset)) {
-    if (!first_tpdu) {
-      if (check_col(fd, COL_INFO))
-        col_append_str(fd, COL_INFO, ", ");
-    }
-    if ((li = pd[offset + P_LI]) == 0) {
-      if (check_col(fd, COL_INFO))
-        col_append_str(fd, COL_INFO, "Length indicator is zero");
-      if (!first_tpdu)
-        dissect_data(pd, offset, fd, tree);
-      return found_cotp;
-    }
-    if (!BYTES_ARE_IN_FRAME(offset, P_LI + li + 1)) {
-      if (check_col(fd, COL_INFO))
-        col_append_str(fd, COL_INFO, "Captured data in frame doesn't include entire frame");
-      if (!first_tpdu)
-        dissect_data(pd, offset, fd, tree);
-      return found_cotp;
-    }
-
-    tpdu    = (pd[offset + P_TPDU] >> 4) & 0x0F;
-    cdt     = pd[offset + P_CDT] & 0x0F;
-    dst_ref = EXTRACT_SHORT(&pd[offset + P_DST_REF]);
-
-    switch (tpdu) {
-      case CC_TPDU :
-      case CR_TPDU :
-        new_offset = osi_decode_CC(pd, offset, fd, tree);
-        break;
-      case DR_TPDU :
-        new_offset = osi_decode_DR(pd, offset, fd, tree);
-        break;
-      case DT_TPDU :
-        if (osi_decode_DT(pd, offset, fd, tree, uses_inactive_subset))
-          subdissector_found = TRUE;
-        new_offset = pi.captured_len;	/* DT PDUs run to the end of the packet */
-        break;
-      case ED_TPDU :
-        new_offset = osi_decode_ED(pd, offset, fd, tree);
-        break;
-      case RJ_TPDU :
-        new_offset = osi_decode_RJ(pd, offset, fd, tree);
-        break;
-      case DC_TPDU :
-        new_offset = osi_decode_DC(pd, offset, fd, tree);
-        break;
-      case AK_TPDU :
-        new_offset = osi_decode_AK(pd, offset, fd, tree);
-        break;
-      case EA_TPDU :
-        new_offset = osi_decode_EA(pd, offset, fd, tree);
-        break;
-      case ER_TPDU :
-        new_offset = osi_decode_ER(pd, offset, fd, tree);
-        break;
-      default      :
-        if (first_tpdu && check_col(fd, COL_INFO))
-          col_append_fstr(fd, COL_INFO, "Unknown TPDU type (0x%x)", tpdu);
-        new_offset = -1;	/* bad PDU type */
-        break;
-    }
-
-    if (new_offset == -1) { /* incorrect TPDU */
-      if (!first_tpdu)
-        dissect_data(pd, offset, fd, tree);
-      break;
-    }
-
-    if (first_tpdu) {
-      /* Well, we found at least one valid COTP PDU, so I guess this
-         is COTP. */
-      if (!subdissector_found && check_col(fd, COL_PROTOCOL))
-        col_add_str(fd, COL_PROTOCOL, "COTP");
-      found_cotp = TRUE;
+  else { /* print standard format */
+    if ( 4 < length ) { 
+      while ( tmp < length / 4 ) {      /* 16/4==4  four Octets left to print */
+        cur += sprintf( str, "%02x%02x%02x%02x.", buffer[tmp++], buffer[tmp++],
+                        buffer[tmp++], buffer[tmp++] );
+      }
+      if ( 1 == tmp ) {                     /* Special case for Designated IS */
+        sprintf( --cur, "-%02x", buffer[tmp] );
+      }
+      else {
+        for ( ; tmp < length; ) {  /* print the rest without dot */ 
+          cur += sprintf( cur, "%02x", buffer[tmp++] );
+        }
+      } 
     }
-
-    offset = new_offset;
-    first_tpdu = FALSE;
+    return( str );
   }
-  return found_cotp;
-} /* dissect_cotp_internal */
+} /* print_area */
 
-void dissect_cotp(const u_char *pd, int offset, frame_data *fd,
-		  proto_tree *tree) 
-{
-  if (!dissect_cotp_internal(pd, offset, fd, tree, FALSE))
-    dissect_data(pd, offset, fd, tree);
-}
-
-
-/*
- *  CLNP part 
- */
-
-#define MAX_NSAP_LEN	20
 
-static gchar *print_nsap(const u_char *nsap, int length)
+gchar *print_nsap_net( const u_char *buffer, int length)
 {
+  /* to do : NSAP / NET decoding */
 
-  /* to do : real NSAP decoding */
+  static gchar  str[MAX_NSAP_LEN * 3 + 50]; /* reserve space for nice layout */
+  gchar *cur;
 
-  static gchar  str[3][MAX_NSAP_LEN * 3 + 1];
-  static gchar *cur;
-  gchar tmp[5];
+  cur = str;
 
-  if (cur == &str[0][0]) {
-    cur = &str[1][0];
-  } else if (cur == &str[1][0]) {  
-    cur = &str[2][0];
-  } else {  
-    cur = &str[0][0];
+  if ( (length <= 0 ) || ( length > MAX_NSAP_LEN ) ) {
+    sprintf( str, "<Invalid length of NSAP>");
+    return( str );
   }
-
-  cur[0] = '\0';
-  if (length <= 0 || length > MAX_NSAP_LEN) 
-    sprintf(cur, "<invalid NSAP>");
-  else
-    while (length != 1) {
-      sprintf(tmp, "%02x:", *nsap ++);
-      strcat(cur, tmp);
-      length --;
+  if ( ( length == RFC1237_NSAP_LEN ) || ( length == RFC1237_NSAP_LEN + 1 ) ) {
+    cur += sprintf( cur, "%s", print_area( buffer, RFC1237_FULLAREA_LEN ) );
+    cur += sprintf( cur, "%s", print_system_id( buffer + RFC1237_FULLAREA_LEN, 
+                    RFC1237_SYSTEMID_LEN ) );
+    cur += sprintf( cur, "[%02x]", 
+                    buffer[ RFC1237_FULLAREA_LEN + RFC1237_SYSTEMID_LEN ] );
+    if ( length == RFC1237_NSAP_LEN + 1 ) {
+      cur += sprintf( cur, "-%02x", buffer[ length -1 ] );
     }
-  sprintf(tmp, "%02x", *nsap);
-  strcat(cur, tmp);
-  return cur;
-
-} /* print_nsap */
-
-void dissect_clnp(const u_char *pd, int offset, frame_data *fd,
-		  proto_tree *tree) 
-{
-
-  struct clnp_header clnp;
-  proto_tree *clnp_tree = NULL;
-  proto_item *ti;
-  u_char src_len, dst_len, nsel;
-  u_int first_offset = offset;
-  char flag_string[6+1];
-  char *pdu_type_string;
-  guint16 segment_length;
-  guint16 segment_offset = 0;
-  guint len;
-
-  if (check_col(fd, COL_PROTOCOL))
-    col_add_str(fd, COL_PROTOCOL, "CLNP");
-
-  /* avoid alignment problem */
-  memcpy(&clnp, &pd[offset], sizeof(clnp));
-
-  if (clnp.cnf_proto_id == NLPID_NULL) {
-    if (check_col(fd, COL_INFO))
-      col_add_str(fd, COL_INFO, "Inactive subset");
-    if (tree) {
-      ti = proto_tree_add_item(tree, proto_clnp, offset, 1, NULL);
-      clnp_tree = proto_item_add_subtree(ti, ett_clnp);
-      proto_tree_add_uint_format(clnp_tree, hf_clnp_id, offset, 1, 
-				 clnp.cnf_proto_id,
-				 "Inactive subset");
-    } 
-    dissect_cotp_internal(pd, offset+1, fd, tree, TRUE);
-    return;
-  } 
- 
-  if (!BYTES_ARE_IN_FRAME(offset, sizeof(clnp))) {
-    dissect_data(pd, offset, fd, tree);
-    return;
+    return ( str );
   }
-
-  /* return if version not known */
-  if (clnp.cnf_vers != ISO8473_V1) {
-    dissect_data(pd, offset, fd, tree);
-    return;
+  else {    /* probably format as standard */
+    return( print_area( buffer, length ) );
   }
+} /* print_nsap */
 
-  /* fixed part decoding */
 
-  segment_length = EXTRACT_SHORT(&clnp.cnf_seglen_msb);
-  flag_string[0] = '\0';
-  if (clnp.cnf_type & CNF_SEG_OK)
-    strcat(flag_string, "S ");
-  if (clnp.cnf_type & CNF_MORE_SEGS)
-    strcat(flag_string, "M ");
-  if (clnp.cnf_type & CNF_ERR_OK)
-    strcat(flag_string, "E ");
-  pdu_type_string = val_to_str(clnp.cnf_type & CNF_TYPE, npdu_type_vals,
-				"Unknown (0x%02x)");
-  if (tree) {
-    ti = proto_tree_add_item(tree, proto_clnp, offset, clnp.cnf_hdr_len, NULL);
-    clnp_tree = proto_item_add_subtree(ti, ett_clnp);
-    proto_tree_add_item(clnp_tree, hf_clnp_id, offset, 1, 
-			       clnp.cnf_proto_id);
-    proto_tree_add_item(clnp_tree, hf_clnp_length, offset +  1, 1, 
-			clnp.cnf_hdr_len); 
-    proto_tree_add_item(clnp_tree, hf_clnp_version, offset +  2, 1, 
-			clnp.cnf_vers);
-    proto_tree_add_uint_format(clnp_tree, hf_clnp_ttl, offset +  3, 1, 
-			       clnp.cnf_ttl,
-			       "TTL: %d (%d secs)", 
-			       clnp.cnf_ttl, clnp.cnf_ttl / 2);
-    proto_tree_add_uint_format(clnp_tree, hf_clnp_type, offset +  4, 1, 
-			       clnp.cnf_type,
-			       "Type code: 0x%02x (%s%s)",
-			       clnp.cnf_type,
-			       flag_string,
-			       pdu_type_string);
-    proto_tree_add_item(clnp_tree, hf_clnp_pdu_length, offset +  5, 2, 
-			segment_length);
-    proto_tree_add_uint_format(clnp_tree, hf_clnp_checksum, offset +  7, 2,
-			       EXTRACT_SHORT(&clnp.cnf_cksum_msb),
-			       "Checksum: 0x%04x",
-			       EXTRACT_SHORT(&clnp.cnf_cksum_msb));
-  } /* tree */
+gchar *calc_checksum( const u_char *buffer, u_int len, u_int checksum) {
+  u_int   calc_sum = 0;
+  u_int   count    = 0;
 
-  /* stop here if header is not complete */
+  static char *checksum_string[] = { "Not Used", 
+                                     "Is good",
+                                     "Is wrong" }; 
+  if ( 0 == checksum )
+    return( checksum_string[0] );
 
-  if (!BYTES_ARE_IN_FRAME(offset, clnp.cnf_hdr_len)) {
-    if (check_col(fd, COL_INFO))
-      col_add_fstr(fd, COL_INFO, "%s NPDU %s", pdu_type_string, flag_string);
-    dissect_data(pd, offset, fd, tree);
-    return;
+  for ( count = 0; count < len; count++ ) {
+    calc_sum += (u_int) buffer[count];
   }
-
-  /* address part */
+  calc_sum %= 255;  /* modulo 255 divison */
   
-  offset += P_ADDRESS_PART;
-  dst_len = pd[offset];
-  nsel    = pd[offset + dst_len];
-  src_len = pd[offset + dst_len + 1];
-
-  if (tree) {
-    proto_tree_add_item(clnp_tree, hf_clnp_dest_length, offset, 1, 
-			dst_len);
-    proto_tree_add_bytes_format(clnp_tree, hf_clnp_dest, offset + 1 , dst_len, 
-			       &pd[offset + 1],
-			       "Destination address: %s", 
-			       print_nsap(&pd[offset + 1], dst_len));
-    proto_tree_add_item(clnp_tree, hf_clnp_src_length, 
-			offset + 1 + dst_len, 1, src_len);
-    proto_tree_add_bytes_format(clnp_tree, hf_clnp_src, 
-			       offset + dst_len + 2, src_len,
-			       &pd[offset + dst_len + 2],
-			       "Source address: %s", 
-			       print_nsap(&pd[offset + dst_len + 2], src_len));
-  }
-
-  if (check_col(fd, COL_RES_NET_SRC))
-    col_add_fstr(fd, COL_RES_NET_SRC, "%s", 
-		 print_nsap(&pd[offset + dst_len + 2], src_len));
-  if (check_col(fd, COL_RES_NET_DST))
-    col_add_fstr(fd, COL_RES_NET_DST, "%s", 
-		 print_nsap(&pd[offset + 1], dst_len));
-
-  /* Segmentation Part */
-
-  offset += dst_len + src_len + 2;
-
-  if (clnp.cnf_type & CNF_SEG_OK) {
-    struct clnp_segment seg;			/* XXX - not used */
-    memcpy(&seg, &pd[offset], sizeof(seg));	/* XXX - not used */
-    
-    segment_offset = EXTRACT_SHORT(&pd[offset + 2]);
-    if (tree) {
-      proto_tree_add_text(clnp_tree, offset, 2, 
-			"Data unit identifier: 0x%04x",
-			EXTRACT_SHORT(&pd[offset]));
-      proto_tree_add_text(clnp_tree, offset + 2 , 2,
-			"Segment offset: %u", 
-			segment_offset);
-      proto_tree_add_text(clnp_tree, offset + 4 , 2,
-			"Total length: %u", 
-			EXTRACT_SHORT(&pd[offset + 4]));
-    }
-    
-    offset += 6;
-  }
-
-  if (tree) {
-    /* To do : decode options  */
-
-    proto_tree_add_text(clnp_tree, offset, 
-			clnp.cnf_hdr_len + first_offset - offset,
-			"Options/Data: <not shown>");
-  }
-
-  /* Length of CLNP datagram plus headers above it. */
-  len = segment_length + first_offset;
-
-  /* Set the payload and captured-payload lengths to the minima of (the
-     datagram length plus the length of the headers above it) and the
-     frame lengths. */
-  if (pi.len > len)
-    pi.len = len;
-  if (pi.captured_len > len)
-    pi.captured_len = len;
-
-  offset = first_offset + clnp.cnf_hdr_len;
-
-  /* For now, dissect the payload of segments other than the initial
-     segment as data, rather than handing them off to the transport
-     protocol, just as we do with fragments other than the first
-     fragment in a fragmented IP datagram; in the future, we will
-     probably reassemble fragments for IP, and may reassemble segments
-     for CLNP. */
-  if ((clnp.cnf_type & CNF_SEG_OK) && segment_offset != 0) {
-    if (check_col(fd, COL_INFO))
-      col_add_fstr(fd, COL_INFO, "Fragmented %s NPDU %s(off=%u)",
-		pdu_type_string, flag_string, segment_offset);
-    dissect_data(pd, offset, fd, tree);
-    return;
-  }
-
-  if (IS_DATA_IN_FRAME(offset)) {
-    switch (clnp.cnf_type & CNF_TYPE) {
-
-    case DT_NPDU:
-    case MD_NPDU:
-      /* Continue with COTP if any data.
-         XXX - if this isn't the first Derived PDU of a segmented Initial
-         PDU, skip that? */
-
-      if (nsel == NSEL_TP) { 	/* just guessing here - valid for DECNet-OSI */
-        if (dissect_cotp_internal(pd, offset, fd, tree, FALSE))
-          return;	/* yes, it appears to be COTP */
-      }
-      break;
-
-    case ER_NPDU:
-      /* The payload is the header and "none, some, or all of the data
-         part of the discarded PDU", i.e. it's like an ICMP error;
-	 just as we don't yet trust ourselves to be able to dissect
-	 the payload of an ICMP error packet, we don't yet trust
-	 ourselves to dissect the payload of a CLNP ER packet. */
-      break;
-
-    case ERQ_NPDU:
-    case ERP_NPDU:
-      /* XXX - dissect this */
-      break;
-    }
-  }
-  if (check_col(fd, COL_INFO))
-    col_add_fstr(fd, COL_INFO, "%s NPDU %s", pdu_type_string, flag_string);
-  dissect_data(pd, offset, fd, tree);
-
-} /* dissect_clnp */
+  if ( 0 == calc_sum )
+    return( checksum_string[1] );
+  else
+    return( checksum_string[2] );
+}
 
 
 /* main entry point */
@@ -1747,7 +217,7 @@ const value_string nlpid_vals[] = {
 	{ NLPID_ISO8473_CLNP,    "CLNP" },
 	{ NLPID_ISO9542_ESIS,    "ESIS" },
 	{ NLPID_ISO10589_ISIS,   "ISIS" },
-	{ NLPID_ISO10747,        "ISO 10747" },
+	{ NLPID_ISO10747_IDRP,   "IDRP" },
 	{ NLPID_ISO9542X25_ESIS, "ESIS (X.25)" },
 	{ NLPID_ISO10030,        "ISO 10030" },
 	{ NLPID_ISO11577,        "ISO 11577" },
@@ -1759,20 +229,16 @@ const value_string nlpid_vals[] = {
 void dissect_osi(const u_char *pd, int offset, frame_data *fd, 
 		 proto_tree *tree) 
 {
-
   switch (pd[offset]) {
 
-    /* ESIS is not currently decoded */
+    /* ESIS (X.25) is not currently decoded */
 
     case NLPID_ISO8473_CLNP:
     case NLPID_NULL:	/* "Inactive Subset" of ISO 8473 CLNP */
       dissect_clnp(pd, offset, fd, tree);
       break;
     case NLPID_ISO9542_ESIS:
-      if (check_col(fd, COL_PROTOCOL)) {
-	col_add_str(fd, COL_PROTOCOL, "ESIS");
-      }
-      dissect_data(pd, offset, fd, tree);
+      dissect_esis(pd, offset, fd, tree);
       break;
     case NLPID_ISO9542X25_ESIS:
       if (check_col(fd, COL_PROTOCOL)) {
@@ -1783,6 +249,12 @@ void dissect_osi(const u_char *pd, int offset, frame_data *fd,
     case NLPID_ISO10589_ISIS:
       dissect_isis(pd, offset, fd, tree);
       break;
+    case NLPID_ISO10747_IDRP:
+      if (check_col(fd, COL_PROTOCOL)) {
+        col_add_str(fd, COL_PROTOCOL, "IDRP");
+      }
+      dissect_data(pd, offset, fd, tree);
+      break;
     default:
       if (check_col(fd, COL_PROTOCOL)) {
 	col_add_str(fd, COL_PROTOCOL, "ISO");
@@ -1793,76 +265,4 @@ void dissect_osi(const u_char *pd, int offset, frame_data *fd,
       dissect_data(pd, offset, fd, tree);
       break;
   }
-  
 } /* dissect_osi */
-
-void proto_register_clnp(void)
-{
-  static hf_register_info hf[] = {
-    { &hf_clnp_id,
-      { "Protocol identifier",	"clnp.id",	FT_UINT8, BASE_HEX, VALS(nlpid_vals), 0x0,
-      	"" }},
-
-    { &hf_clnp_length,
-      { "Length",		"clnp.len",	FT_UINT8, BASE_DEC, NULL, 0x0,
-      	"" }},
-
-    { &hf_clnp_version,
-      { "Version",		"clnp.version", FT_UINT8, BASE_DEC, NULL, 0x0,
-      	"" }},
-
-    { &hf_clnp_ttl,
-      { "TTL",			"clnp.ttl",	FT_UINT8, BASE_DEC, NULL, 0x0,
-      	"" }},
-
-    { &hf_clnp_type,
-      { "Type code",            "clnp.type",	FT_UINT8, BASE_DEC, NULL, 0x0,
-      	"" }},
-
-    { &hf_clnp_pdu_length,
-      { "PDU segment length",   "clnp.pdu.len", FT_UINT16, BASE_DEC, NULL, 0x0,
-      	"" }},
-
-    { &hf_clnp_checksum,
-      { "Checksum",		"clnp.checksum",FT_UINT16, BASE_DEC, NULL, 0x0,
-      	"" }},
-
-    { &hf_clnp_dest_length,
-      { "Destination address length", "clnp.dsap.len", FT_UINT8, BASE_DEC, NULL, 0x0,
-      	"" }},
-
-    { &hf_clnp_dest,
-      { "Destination address",  "clnp.dsap",	FT_BYTES, BASE_NONE, NULL, 0x0,
-      	"" }},
-
-    { &hf_clnp_src_length,
-      { "Source address length","clnp.ssap.len",FT_UINT8, BASE_DEC, NULL, 0x0,
-      	"" }},
-
-    { &hf_clnp_src,
-      { "Source address",       "clnp.ssap",	FT_BYTES, BASE_NONE, NULL, 0x0,
-      	"" }},
-  };
-  static gint *ett[] = {
-    &ett_clnp,
-  };
-
-  proto_clnp = proto_register_protocol("ISO CLNP", "clnp");
-  proto_register_field_array(proto_clnp, hf, array_length(hf));
-  proto_register_subtree_array(ett, array_length(ett));
-}
-
-void proto_register_cotp(void)
-{
-  /*        static hf_register_info hf[] = {
-                { &variable,
-                { "Name",           "cotp.abbreviation", TYPE, VALS_POINTER }},
-        };*/
-	static gint *ett[] = {
-		&ett_cotp,
-	};
-
-        proto_cotp = proto_register_protocol("ISO COTP", "cotp");
- /*       proto_register_field_array(proto_cotp, hf, array_length(hf));*/
-	proto_register_subtree_array(ett, array_length(ett));
-}