If you register more than one field with the same name, the dfilter code

can now handle that; this allows us to register both the modulo-8 and
the modulo-128 versions of various X.25 bitfields with "x.25.XXX" names,
which lets us get rid of the "ex.25" protocol stuff completely and use
"x.25" for both modulo-8 and modulo-128 X.25.  Do so.  (Also, fix up
some cases where we appeared to be using the modulo-8 fields when
dissecting modulo-128 X.25.)

This, in turn, allows us to register the X.25 dissector, as there's now
only one protocol with which it's associated, and make it static and
have it called only through a handle, and to, when registering it with
the "llc.dsap" dissector table, associate it with "proto_x25".

That, in turn, allows us to get rid of the "CHECK_DISPLAY_AS_DATA()"
calls, and the code to set "pinfo->current_proto", in the X.25
dissector.

The code for the display filter expression dialog would, if there are
two fields with the same name registered under a protocol, list both of
them; have it list only one of them - the fields should have the same
type, the same radix, and the same value_string/true_false_string table
if any (if they don't, they're really not the same field...).

svn path=/trunk/; revision=3023

1 files changed, 93 insertions, 163 deletions

diff --git a/packet-x25.c b/packet-x25.c
index adc83cdf95..a0f1b70cc5 100644
--- a/packet-x25.c
+++ b/packet-x25.c
@@ -2,7 +2,7 @@
  * Routines for x25 packet disassembly
  * Olivier Abad <oabad@cybercable.fr>
  *
- * $Id: packet-x25.c,v 1.45 2001/01/09 06:31:45 guy Exp $
+ * $Id: packet-x25.c,v 1.46 2001/02/12 09:06:17 guy Exp $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@zing.org>
@@ -39,7 +39,6 @@
 #include "etypes.h"
 #include "llcsaps.h"
 #include "packet.h"
-#include "packet-x25.h"
 #include "packet-ip.h"
 #include "packet-osi.h"
 #include "nlpid.h"
@@ -99,20 +98,12 @@ static int hf_x25_dbit = -1;
 static int hf_x25_mod = -1;
 static int hf_x25_lcn = -1;
 static int hf_x25_type = -1;
-static int hf_x25_p_r = -1;
-static int hf_x25_mbit = -1;
-static int hf_x25_p_s = -1;
-static int proto_ex25 = -1;
-static int hf_ex25_gfi = -1;
-static int hf_ex25_abit = -1;
-static int hf_ex25_qbit = -1;
-static int hf_ex25_dbit = -1;
-static int hf_ex25_mod = -1;
-static int hf_ex25_lcn = -1;
-static int hf_ex25_type = -1;
-static int hf_ex25_p_r = -1;
-static int hf_ex25_mbit = -1;
-static int hf_ex25_p_s = -1;
+static int hf_x25_p_r_mod8 = -1;
+static int hf_x25_p_r_mod128 = -1;
+static int hf_x25_mbit_mod8 = -1;
+static int hf_x25_mbit_mod128 = -1;
+static int hf_x25_p_s_mod8 = -1;
+static int hf_x25_p_s_mod128 = -1;
 
 static gint ett_x25 = -1;
 static gint ett_x25_gfi = -1;
@@ -1394,7 +1385,7 @@ static const value_string sharing_strategy_vals[] = {
         {0x00,            NULL}
 };
 
-void
+static void
 dissect_x25(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 {
     proto_tree *x25_tree=0, *gfi_tree=0;
@@ -1409,8 +1400,6 @@ dissect_x25(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
     guint8 pkt_type;
     tvbuff_t *next_tvb;
 
-    pinfo->current_proto = "X.25";
-
     if (check_col(pinfo->fd, COL_PROTOCOL))
 	col_set_str(pinfo->fd, COL_PROTOCOL, "X.25");
 
@@ -1419,12 +1408,6 @@ dissect_x25(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
     modulo = ((bytes0_1 & 0x2000) ? 128 : 8);
     vc     = (int)(bytes0_1 & 0x0FFF);
 
-    if (modulo == 8) {
-      CHECK_DISPLAY_AS_DATA(proto_x25, tvb, pinfo, tree);
-    } else {
-      CHECK_DISPLAY_AS_DATA(proto_ex25, tvb, pinfo, tree);
-    }
-
     if (bytes0_1 & 0x8000) toa = TRUE;
     else toa = FALSE;
 
@@ -1434,8 +1417,7 @@ dissect_x25(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 	if (check_col(pinfo->fd, COL_INFO))
 	    col_set_str(pinfo->fd, COL_INFO, "Invalid/short X.25 packet");
 	if (tree)
-	    proto_tree_add_protocol_format(tree,
-		    (modulo == 8 ? proto_x25 : proto_ex25), tvb, 0,
+	    proto_tree_add_protocol_format(tree, proto_x25, tvb, 0,
 		    tvb_length(tvb), "Invalid/short X.25 packet");
 	return;
     }
@@ -1443,31 +1425,24 @@ dissect_x25(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
     pkt_type = tvb_get_guint8(tvb, 2);
 
     if (tree) {
-	ti = proto_tree_add_protocol_format(tree,
-		(modulo == 8) ? proto_x25 : proto_ex25, tvb, 0, x25_pkt_len,
-		"X.25");
+	ti = proto_tree_add_item(tree, proto_x25, tvb, 0, x25_pkt_len, FALSE);
 	x25_tree = proto_item_add_subtree(ti, ett_x25);
-	ti = proto_tree_add_item(x25_tree,
-		(modulo == 8) ? hf_x25_gfi : hf_ex25_gfi, tvb, 0, 2, FALSE);
+	ti = proto_tree_add_item(x25_tree, hf_x25_gfi, tvb, 0, 2, FALSE);
 	gfi_tree = proto_item_add_subtree(ti, ett_x25_gfi);
 	if ((pkt_type & 0x01) == X25_DATA)
-	    proto_tree_add_boolean(gfi_tree,
-		    (modulo == 8) ? hf_x25_qbit : hf_ex25_qbit, tvb, 0, 2,
+	    proto_tree_add_boolean(gfi_tree, hf_x25_qbit, tvb, 0, 2,
 		    bytes0_1);
 	else if (pkt_type == X25_CALL_REQUEST ||
 		pkt_type == X25_CALL_ACCEPTED ||
 		pkt_type == X25_CLEAR_REQUEST ||
 		pkt_type == X25_CLEAR_CONFIRMATION)
-	    proto_tree_add_boolean(gfi_tree,
-		    (modulo == 8) ? hf_x25_abit : hf_ex25_abit, tvb, 0, 2,
+	    proto_tree_add_boolean(gfi_tree, hf_x25_abit, tvb, 0, 2,
 		    bytes0_1);
 	if (pkt_type == X25_CALL_REQUEST || pkt_type == X25_CALL_ACCEPTED ||
 		(pkt_type & 0x01) == X25_DATA)
-	    proto_tree_add_boolean(gfi_tree,
-		    (modulo == 8) ? hf_x25_dbit : hf_ex25_dbit, tvb, 0, 2,
+	    proto_tree_add_boolean(gfi_tree, hf_x25_dbit, tvb, 0, 2,
 		    bytes0_1);
-	proto_tree_add_uint(gfi_tree, (modulo == 8) ? hf_x25_mod : hf_ex25_mod,
-		tvb, 0, 2, bytes0_1);
+	proto_tree_add_uint(gfi_tree, hf_x25_mod, tvb, 0, 2, bytes0_1);
     }
 
     switch (pkt_type) {
@@ -1478,11 +1453,9 @@ dissect_x25(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 		                                                 : "Call req." ,
                     vc);
 	if (x25_tree) {
-	    proto_tree_add_uint(x25_tree,
-		    (modulo == 8) ? hf_x25_lcn : hf_ex25_lcn, tvb,
+	    proto_tree_add_uint(x25_tree, hf_x25_lcn, tvb,
 		    0, 2, bytes0_1);
-	    proto_tree_add_uint_format(x25_tree,
-		    (modulo == 8) ? hf_x25_type : hf_ex25_type, tvb, 2, 1,
+	    proto_tree_add_uint_format(x25_tree, hf_x25_type, tvb, 2, 1,
 		    X25_CALL_REQUEST,
 		    (pinfo->pseudo_header->x25.flags & FROM_DCE) ? "Incoming call"
 			                                         : "Call request");
@@ -1592,11 +1565,9 @@ dissect_x25(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 			                                         : "Call acc." ,
 		    vc);
 	if (x25_tree) {
-	    proto_tree_add_uint(x25_tree, (modulo == 8) ? hf_x25_lcn : hf_ex25_lcn,
-		    tvb, 0, 2, bytes0_1);
-	    proto_tree_add_uint_format(x25_tree,
-		    (modulo == 8) ? hf_x25_type : hf_ex25_type,
-		    tvb, 2, 1, X25_CALL_ACCEPTED,
+	    proto_tree_add_uint(x25_tree, hf_x25_lcn, tvb, 0, 2, bytes0_1);
+	    proto_tree_add_uint_format(x25_tree, hf_x25_type, tvb, 2, 1,
+	    	    X25_CALL_ACCEPTED,
 		    (pinfo->pseudo_header->x25.flags & FROM_DCE) ? "Call connected"
 		                                                 : "Call accepted");
 	}
@@ -1624,11 +1595,9 @@ dissect_x25(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 	}
 	x25_hash_add_proto_end(vc, pinfo->fd->abs_secs, pinfo->fd->abs_usecs);
 	if (x25_tree) {
-	    proto_tree_add_uint(x25_tree, (modulo == 8) ? hf_x25_lcn : hf_ex25_lcn, tvb,
-		    0, 2, bytes0_1);
-	    proto_tree_add_uint_format(x25_tree,
-		    (modulo == 8) ? hf_x25_type : hf_ex25_type,
-		    tvb, localoffset+2, 1, X25_CLEAR_REQUEST,
+	    proto_tree_add_uint(x25_tree, hf_x25_lcn, tvb, 0, 2, bytes0_1);
+	    proto_tree_add_uint_format(x25_tree, hf_x25_type, tvb,
+	    	    localoffset+2, 1, X25_CLEAR_REQUEST,
 		    (pinfo->pseudo_header->x25.flags & FROM_DCE) ? "Clear indication"
 		                                                 : "Clear request");
 	    proto_tree_add_text(x25_tree, tvb, 3, 1,
@@ -1642,10 +1611,9 @@ dissect_x25(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 	if(check_col(pinfo->fd, COL_INFO))
 	    col_add_fstr(pinfo->fd, COL_INFO, "Clear Conf. VC:%d", vc);
 	if (x25_tree) {
-	    proto_tree_add_uint(x25_tree, (modulo == 8) ? hf_x25_lcn : hf_ex25_lcn, tvb,
-		    0, 2, bytes0_1);
-	    proto_tree_add_uint(x25_tree, (modulo == 8) ? hf_x25_type : hf_ex25_type, tvb,
-		    2, 1, X25_CLEAR_CONFIRMATION);
+	    proto_tree_add_uint(x25_tree, hf_x25_lcn, tvb, 0, 2, bytes0_1);
+	    proto_tree_add_uint(x25_tree, hf_x25_type, tvb, 2, 1,
+		    X25_CLEAR_CONFIRMATION);
 	}
 	localoffset = x25_pkt_len;
 
@@ -1661,8 +1629,8 @@ dissect_x25(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 		    (int)tvb_get_guint8(tvb, 3));
 	}
 	if (x25_tree) {
-	    proto_tree_add_uint(x25_tree, (modulo == 8) ? hf_x25_type : hf_ex25_type, tvb,
-		    2, 1, X25_DIAGNOSTIC);
+	    proto_tree_add_uint(x25_tree, hf_x25_type, tvb, 2, 1,
+		    X25_DIAGNOSTIC);
 	    proto_tree_add_text(x25_tree, tvb, 3, 1,
 		    "Diagnostic : %d", (int)tvb_get_guint8(tvb, 3));
 	}
@@ -1672,10 +1640,9 @@ dissect_x25(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 	if(check_col(pinfo->fd, COL_INFO))
 	    col_add_fstr(pinfo->fd, COL_INFO, "Interrupt VC:%d", vc);
 	if (x25_tree) {
-	    proto_tree_add_uint(x25_tree, (modulo == 8) ? hf_x25_lcn : hf_ex25_lcn, tvb,
-		    0, 2, bytes0_1);
-	    proto_tree_add_uint(x25_tree, (modulo == 8) ? hf_x25_type : hf_ex25_type, tvb,
-		    2, 1, X25_INTERRUPT);
+	    proto_tree_add_uint(x25_tree, hf_x25_lcn, tvb, 0, 2, bytes0_1);
+	    proto_tree_add_uint(x25_tree, hf_x25_type, tvb, 2, 1,
+		    X25_INTERRUPT);
 	}
 	localoffset = x25_pkt_len;
 	break;
@@ -1683,10 +1650,9 @@ dissect_x25(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 	if(check_col(pinfo->fd, COL_INFO))
 	    col_add_fstr(pinfo->fd, COL_INFO, "Interrupt Conf. VC:%d", vc);
 	if (x25_tree) {
-	    proto_tree_add_uint(x25_tree, (modulo == 8) ? hf_x25_lcn : hf_ex25_lcn, tvb,
-		    0, 2, bytes0_1);
-	    proto_tree_add_uint(x25_tree, (modulo == 8) ? hf_x25_type : hf_ex25_type, tvb,
-		    2, 1, X25_INTERRUPT_CONFIRMATION);
+	    proto_tree_add_uint(x25_tree, hf_x25_lcn, tvb, 0, 2, bytes0_1);
+	    proto_tree_add_uint(x25_tree, hf_x25_type, tvb, 2, 1,
+		    X25_INTERRUPT_CONFIRMATION);
 	}
 	localoffset = x25_pkt_len;
 	break;
@@ -1700,10 +1666,8 @@ dissect_x25(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 	}
 	x25_hash_add_proto_end(vc, pinfo->fd->abs_secs, pinfo->fd->abs_usecs);
 	if (x25_tree) {
-	    proto_tree_add_uint(x25_tree, (modulo == 8) ? hf_x25_lcn : hf_ex25_lcn, tvb,
-		    0, 2, bytes0_1);
-	    proto_tree_add_uint_format(x25_tree,
-		    (modulo == 8) ? hf_x25_type : hf_ex25_type, tvb, 2, 1,
+	    proto_tree_add_uint(x25_tree, hf_x25_lcn, tvb, 0, 2, bytes0_1);
+	    proto_tree_add_uint_format(x25_tree, hf_x25_type, tvb, 2, 1,
 		    X25_RESET_REQUEST,
 		    (pinfo->pseudo_header->x25.flags & FROM_DCE) ? "Reset indication"
                                                                  : "Reset request");
@@ -1718,10 +1682,9 @@ dissect_x25(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 	if(check_col(pinfo->fd, COL_INFO))
 	    col_add_fstr(pinfo->fd, COL_INFO, "Reset conf. VC:%d", vc);
 	if (x25_tree) {
-	    proto_tree_add_uint(x25_tree, (modulo == 8) ? hf_x25_lcn : hf_ex25_lcn, tvb,
-		    0, 2, bytes0_1);
-	    proto_tree_add_uint(x25_tree, (modulo == 8) ? hf_x25_type : hf_ex25_type, tvb,
-		    2, 1, X25_RESET_CONFIRMATION);
+	    proto_tree_add_uint(x25_tree, hf_x25_lcn, tvb, 0, 2, bytes0_1);
+	    proto_tree_add_uint(x25_tree, hf_x25_type, tvb, 2, 1,
+		    X25_RESET_CONFIRMATION);
 	}
 	localoffset = x25_pkt_len;
 	break;
@@ -1734,8 +1697,7 @@ dissect_x25(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 		    (int)tvb_get_guint8(tvb, 3));
 	}
 	if (x25_tree) {
-	    proto_tree_add_uint_format(x25_tree,
-		    (modulo == 8) ? hf_x25_type : hf_ex25_type, tvb, 2, 1,
+	    proto_tree_add_uint_format(x25_tree, hf_x25_type, tvb, 2, 1,
 		    X25_RESTART_REQUEST,
 		    (pinfo->pseudo_header->x25.flags & FROM_DCE) ? "Restart indication"
 		                                                 : "Restart request");
@@ -1750,16 +1712,16 @@ dissect_x25(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 	if(check_col(pinfo->fd, COL_INFO))
 	    col_set_str(pinfo->fd, COL_INFO, "Restart conf.");
 	if (x25_tree)
-	    proto_tree_add_uint(x25_tree, (modulo == 8) ? hf_x25_type : hf_ex25_type, tvb,
-		    2, 1, X25_RESTART_CONFIRMATION);
+	    proto_tree_add_uint(x25_tree, hf_x25_type, tvb, 2, 1,
+		    X25_RESTART_CONFIRMATION);
 	localoffset = x25_pkt_len;
 	break;
     case X25_REGISTRATION_REQUEST:
 	if(check_col(pinfo->fd, COL_INFO))
 	    col_set_str(pinfo->fd, COL_INFO, "Registration req.");
 	if (x25_tree)
-	    proto_tree_add_uint(x25_tree, (modulo == 8) ? hf_x25_type : hf_ex25_type, tvb,
-		    2, 1, X25_REGISTRATION_REQUEST);
+	    proto_tree_add_uint(x25_tree, hf_x25_type, tvb, 2, 1,
+		    X25_REGISTRATION_REQUEST);
 	localoffset = 3;
 	if (localoffset < x25_pkt_len)
 	    x25_ntoa(x25_tree, &localoffset, tvb, pinfo->fd, FALSE);
@@ -1780,8 +1742,8 @@ dissect_x25(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 	if(check_col(pinfo->fd, COL_INFO))
 	    col_set_str(pinfo->fd, COL_INFO, "Registration conf.");
 	if (x25_tree) {
-	    proto_tree_add_uint(x25_tree, (modulo == 8) ? hf_x25_type : hf_ex25_type, tvb,
-		    2, 1, X25_REGISTRATION_CONFIRMATION);
+	    proto_tree_add_uint(x25_tree, hf_x25_type, tvb, 2, 1,
+		    X25_REGISTRATION_CONFIRMATION);
 	    proto_tree_add_text(x25_tree, tvb, 3, 1,
 		    "Cause: %s", registration_code(tvb_get_guint8(tvb, 3)));
 	    proto_tree_add_text(x25_tree, tvb, 4, 1,
@@ -1822,32 +1784,32 @@ dissect_x25(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 			    (tvb_get_guint8(tvb, localoffset+1) & 0x01) ? " M" : "");
 	    }
 	    if (x25_tree) {
-		proto_tree_add_uint(x25_tree, (modulo == 8) ? hf_x25_lcn : hf_ex25_lcn,
-			tvb, localoffset-2, 2, bytes0_1);
+		proto_tree_add_uint(x25_tree, hf_x25_lcn, tvb, localoffset-2,
+			2, bytes0_1);
+		proto_tree_add_uint_hidden(x25_tree, hf_x25_type, tvb,
+			localoffset, 1, X25_DATA);
 		if (modulo == 8) {
-		    proto_tree_add_uint_hidden(x25_tree, hf_x25_type, tvb,
-			    localoffset, 1, X25_DATA);
-		    proto_tree_add_uint(x25_tree, hf_x25_p_r, tvb,
+		    proto_tree_add_uint(x25_tree, hf_x25_p_r_mod8, tvb,
 			    localoffset, 1, pkt_type);
 		    if (pkt_type & 0x10)
-			proto_tree_add_boolean(x25_tree, hf_x25_mbit, tvb, localoffset, 1,
-			    pkt_type);
-		    proto_tree_add_uint(x25_tree, hf_x25_p_s, tvb, localoffset, 1,
-			    pkt_type);
+			proto_tree_add_boolean(x25_tree, hf_x25_mbit_mod8, tvb,
+			    localoffset, 1, pkt_type);
+		    proto_tree_add_uint(x25_tree, hf_x25_p_s_mod8, tvb,
+			    localoffset, 1, pkt_type);
 		    proto_tree_add_text(x25_tree, tvb, localoffset, 1,
 			    decode_boolean_bitfield(pkt_type, 0x01, 1*8,
 				NULL, "DATA"));
 		}
 		else {
-		    proto_tree_add_uint_hidden(x25_tree, hf_ex25_type, tvb,
-			    localoffset, 1, X25_DATA);
-		    proto_tree_add_uint(x25_tree, hf_x25_p_r, tvb,
+		    proto_tree_add_uint(x25_tree, hf_x25_p_r_mod128, tvb,
 			    localoffset, 1, pkt_type);
-		    proto_tree_add_uint(x25_tree, hf_x25_p_s, tvb,
-			    localoffset+1, 1, tvb_get_guint8(tvb, localoffset+1));
+		    proto_tree_add_uint(x25_tree, hf_x25_p_s_mod128, tvb,
+			    localoffset+1, 1,
+			    tvb_get_guint8(tvb, localoffset+1));
 		    if (tvb_get_guint8(tvb, localoffset+1) & 0x01)
-			proto_tree_add_boolean(x25_tree, hf_ex25_mbit, tvb,
-				localoffset+1, 1, tvb_get_guint8(tvb, localoffset+1));
+			proto_tree_add_boolean(x25_tree, hf_x25_mbit_mod128, tvb,
+				localoffset+1, 1,
+				tvb_get_guint8(tvb, localoffset+1));
 		}
 	    }
 	    localoffset += (modulo == 8) ? 1 : 2;
@@ -1865,18 +1827,18 @@ dissect_x25(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 			    vc, tvb_get_guint8(tvb, localoffset+1) >> 1);
 	    }
 	    if (x25_tree) {
-		proto_tree_add_uint(x25_tree, (modulo == 8) ? hf_x25_lcn : hf_ex25_lcn,
-			tvb, localoffset-2, 2, bytes0_1);
+		proto_tree_add_uint(x25_tree, hf_x25_lcn, tvb, localoffset-2,
+			2, bytes0_1);
 		if (modulo == 8) {
-		    proto_tree_add_uint(x25_tree, hf_x25_p_r, tvb,
+		    proto_tree_add_uint(x25_tree, hf_x25_p_r_mod8, tvb,
 			    localoffset, 1, pkt_type);
 		    proto_tree_add_uint(x25_tree, hf_x25_type, tvb,
 			    localoffset, 1, X25_RR);
 		}
 		else {
-		    proto_tree_add_uint(x25_tree, hf_ex25_type, tvb,
+		    proto_tree_add_uint(x25_tree, hf_x25_type, tvb,
 			    localoffset, 1, X25_RR);
-		    proto_tree_add_item(x25_tree, hf_ex25_p_r, tvb,
+		    proto_tree_add_item(x25_tree, hf_x25_p_r_mod128, tvb,
 			    localoffset+1, 1, FALSE);
 		}
 	    }
@@ -1892,18 +1854,18 @@ dissect_x25(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 			    vc, tvb_get_guint8(tvb, localoffset+1) >> 1);
 	    }
 	    if (x25_tree) {
-		proto_tree_add_uint(x25_tree, (modulo == 8) ? hf_x25_lcn : hf_ex25_lcn,
-			tvb, localoffset-2, 2, bytes0_1);
+		proto_tree_add_uint(x25_tree, hf_x25_lcn, tvb, localoffset-2,
+			2, bytes0_1);
 		if (modulo == 8) {
-		    proto_tree_add_uint(x25_tree, hf_x25_p_r, tvb,
+		    proto_tree_add_uint(x25_tree, hf_x25_p_r_mod8, tvb,
 			    localoffset, 1, pkt_type);
 		    proto_tree_add_uint(x25_tree, hf_x25_type, tvb,
 			    localoffset, 1, X25_RNR);
 		}
 		else {
-		    proto_tree_add_uint(x25_tree, hf_ex25_type, tvb,
+		    proto_tree_add_uint(x25_tree, hf_x25_type, tvb,
 			    localoffset, 1, X25_RNR);
-		    proto_tree_add_item(x25_tree, hf_ex25_p_r, tvb,
+		    proto_tree_add_item(x25_tree, hf_x25_p_r_mod128, tvb,
 			    localoffset+1, 1, FALSE);
 		}
 	    }
@@ -1919,18 +1881,18 @@ dissect_x25(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 			    vc, tvb_get_guint8(tvb, localoffset+1) >> 1);
 	    }
 	    if (x25_tree) {
-		proto_tree_add_uint(x25_tree, (modulo == 8) ? hf_x25_lcn : hf_ex25_lcn,
-			tvb, localoffset-2, 2, bytes0_1);
+		proto_tree_add_uint(x25_tree, hf_x25_lcn, tvb, localoffset-2,
+			2, bytes0_1);
 		if (modulo == 8) {
-		    proto_tree_add_uint(x25_tree, hf_x25_p_r, tvb,
+		    proto_tree_add_uint(x25_tree, hf_x25_p_r_mod8, tvb,
 			    localoffset, 1, pkt_type);
 		    proto_tree_add_uint(x25_tree, hf_x25_type, tvb,
 			    localoffset, 1, X25_REJ);
 		}
 		else {
-		    proto_tree_add_uint(x25_tree, hf_ex25_type, tvb,
+		    proto_tree_add_uint(x25_tree, hf_x25_type, tvb,
 			    localoffset, 1, X25_REJ);
-		    proto_tree_add_item(x25_tree, hf_ex25_p_r, tvb,
+		    proto_tree_add_item(x25_tree, hf_x25_p_r_mod128, tvb,
 			    localoffset+1, 1, FALSE);
 		}
 	    }
@@ -1960,7 +1922,7 @@ dissect_x25(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 void
 proto_register_x25(void)
 {
-    static hf_register_info hf8[] = {
+    static hf_register_info hf[] = {
 	{ &hf_x25_gfi,
 	  { "GFI", "x.25.gfi", FT_UINT16, BASE_BIN, NULL, 0xF000,
 	  	"General format identifier" } },
@@ -1982,47 +1944,23 @@ proto_register_x25(void)
 	{ &hf_x25_type,
 	  { "Packet Type", "x.25.type", FT_UINT8, BASE_HEX, VALS(vals_x25_type), 0x0,
 	  	"Packet Type" } },
-	{ &hf_x25_p_r,
+	{ &hf_x25_p_r_mod8,
 	  { "P(R)", "x.25.p_r", FT_UINT8, BASE_HEX, NULL, 0xE0,
 	  	"Packet Receive Sequence Number" } },
-	{ &hf_x25_mbit,
+	{ &hf_x25_p_r_mod128,
+	  { "P(R)", "x.25.p_r", FT_UINT8, BASE_HEX, NULL, 0xFE,
+	  	"Packet Receive Sequence Number" } },
+	{ &hf_x25_mbit_mod8,
 	  { "M Bit", "x.25.m", FT_BOOLEAN, 8, NULL, 0x10,
 	  	"More Bit" } },
-	{ &hf_x25_p_s,
+	{ &hf_x25_mbit_mod128,
+	  { "M Bit", "x.25.m", FT_BOOLEAN, 8, NULL, 0x01,
+	  	"More Bit" } },
+	{ &hf_x25_p_s_mod8,
 	  { "P(S)", "x.25.p_s", FT_UINT8, BASE_HEX, NULL, 0x0E,
 	  	"Packet Send Sequence Number" } },
-    };
-
-    static hf_register_info hf128[] = {
-	{ &hf_ex25_gfi,
-	  { "GFI", "ex.25.gfi", FT_UINT16, BASE_BIN, NULL, 0xF000,
-	  	"General format identifier" } },
-	{ &hf_ex25_abit,
-	  { "A Bit", "ex.25.a", FT_BOOLEAN, 16, NULL, 0x8000,
-	  	"Address Bit" } },
-	{ &hf_ex25_qbit,
-	  { "Q Bit", "ex.25.q", FT_BOOLEAN, 16, NULL, 0x8000,
-	  	"Qualifier Bit" } },
-	{ &hf_ex25_dbit,
-	  { "D Bit", "ex.25.d", FT_BOOLEAN, 16, NULL, 0x4000,
-	  	"Delivery Confirmation Bit" } },
-	{ &hf_ex25_mod,
-	  { "Modulo", "ex.25.mod", FT_UINT16, BASE_DEC, VALS(vals_modulo), 0x3000,
-	  	"Specifies whether the frame is modulo 8 or 128" } },
-	{ &hf_ex25_lcn,
-	  { "Logical Channel", "ex.25.lcn", FT_UINT16, BASE_HEX, NULL, 0x0FFF,
-	  	"Logical Channel Number" } },
-	{ &hf_ex25_type,
-	  { "Packet Type", "ex.25.type", FT_UINT8, BASE_HEX, VALS(vals_x25_type), 0x0,
-	  	"Packet Type" } },
-	{ &hf_ex25_p_r,
-	  { "P(R)", "ex.25.p_r", FT_UINT8, BASE_HEX, NULL, 0xFE,
-	  	"Packet Receive Sequence Number" } },
-	{ &hf_ex25_mbit,
-	  { "M Bit", "ex.25.m", FT_BOOLEAN, 8, NULL, 0x01,
-	  	"More Bit" } },
-	{ &hf_ex25_p_s,
-	  { "P(S)", "ex.25.p_s", FT_UINT8, BASE_HEX, NULL, 0xFE,
+	{ &hf_x25_p_s_mod128,
+	  { "P(S)", "x.25.p_s", FT_UINT8, BASE_HEX, NULL, 0xFE,
 	  	"Packet Send Sequence Number" } },
     };
     static gint *ett[] = {
@@ -2052,12 +1990,11 @@ proto_register_x25(void)
     };
 
     proto_x25 = proto_register_protocol ("X.25", "X.25", "x.25");
-    proto_ex25 = proto_register_protocol ("Extended X.25 (modulo 128)",
-        "Extended X.25", "ex.25");
-    proto_register_field_array (proto_x25, hf8, array_length(hf8));
-    proto_register_field_array (proto_ex25, hf128, array_length(hf128));
+    proto_register_field_array (proto_x25, hf, array_length(hf));
     proto_register_subtree_array(ett, array_length(ett));
     register_init_routine(&reinit_x25_hashtable);
+
+    register_dissector("x.25", dissect_x25, proto_x25);
 }
 
 void
@@ -2069,12 +2006,5 @@ proto_reg_handoff_x25(void)
     ip_handle = find_dissector("ip");
     ositp_handle = find_dissector("ositp");
 
-    /*
-     * XXX - we can't associate this with both "proto_x25" and
-     * "proto_ex25"; we really should have only one X.25 protocol,
-     * but to do that right, we need to arrange that, for example,
-     * we can have two field definitions with the name "x.25.p_r",
-     * one for modulo-8 operation and one for modulo-128 operation.
-     */
-    dissector_add("llc.dsap", SAP_X25, dissect_x25, -1);
+    dissector_add("llc.dsap", SAP_X25, dissect_x25, proto_x25);
 }