Add "tvb_reported_length()" to get the "reported length" of a tvbuff

(i.e., the amount of data that was in the packet, even if not all of it
was captured), for use when dissecting packets containing data that
fills the packet (we want the dissector to try to dissect all of it; if
it runs past the end of the captured data, we want it to throw an
exception so that we'll put a "Short Frame" note in the protocol tree).

This means we always want a tvbuff to have a real reported length value,
so we make it an unsigned integer, and don't bother checking it for -1,
as it should never be -1.

If the reported length passed in to "tvb_set_subset()" is -1, set the
reported length to the reported length of the tvbuff of which the new
tvbuff will be a subset minus the offset in that tvbuff of the subset,
so that "-1" means "what's left of the packet after we chop off the
header".  This is necessary in order to ensure that all tvbuffs have a
real reported length value.

Have "dissect_packet()" set the reported length of the top-level tvbuff
to the reported length of the frame, so that we start out with a tvbuff
with a real reported length value.

Have "tvb_offset_exists()" return FALSE if the offset is past the end of
the tvbuff.

If the offset passed to it is postitive, have "compute_offset_length()"
check for that it's not more than one byte past the end of the tvbuff -
if it's just past the end, we don't want the check to fail, as we don't
want attempts to create a subset tvbuff containing zero bytes to fail;
that would be done if a captured packet was all header and no payload,
and we'd want the dissector of the payload, not the dissector of the
header, to throw an exception, as the problem isn't with the protocol
for the header, it's with the protocol for the payload.

Convert the ATM dissector, the SSCOP dissector, the Q.2931 dissector,
and the Q.931 dissector to use tvbuffs.

Make the LAPD dissector set up a tvbuff for the Q.931 dissector (it's
not converted yet).

svn path=/trunk/; revision=2023

1 files changed, 158 insertions, 152 deletions

diff --git a/packet-atm.c b/packet-atm.c
index 5a7bbcfb59..500c41a485 100644
--- a/packet-atm.c
+++ b/packet-atm.c
@@ -1,7 +1,7 @@
 /* packet-atm.c
  * Routines for ATM packet disassembly
  *
- * $Id: packet-atm.c,v 1.20 2000/05/19 23:06:08 gram Exp $
+ * $Id: packet-atm.c,v 1.21 2000/05/29 08:57:36 guy Exp $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@zing.org>
@@ -148,22 +148,22 @@ static const value_string le_control_lan_type_vals[] = {
 };
 
 static void
-dissect_le_client(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) 
+dissect_le_client(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 {
   proto_item *ti;
   proto_tree *lane_tree;
 
   if (tree) {
-    ti = proto_tree_add_protocol_format(tree, proto_atm_lane, NullTVB, offset, 2, "ATM LANE");
+    ti = proto_tree_add_protocol_format(tree, proto_atm_lane, tvb, 0, 2, "ATM LANE");
     lane_tree = proto_item_add_subtree(ti, ett_atm_lane);
 
-    proto_tree_add_text(lane_tree, NullTVB, offset, 2, "LE Client: 0x%04X",
-			pntohs(&pd[offset]));
+    proto_tree_add_text(lane_tree, tvb, 0, 2, "LE Client: 0x%04X",
+			tvb_get_ntohs(tvb, 0));
   }
 }
 
 static void
-dissect_lan_destination(const u_char *pd, int offset, const char *type, proto_tree *tree) 
+dissect_lan_destination(tvbuff_t *tvb, int offset, const char *type, proto_tree *tree) 
 {
   proto_item *td;
   proto_tree *dest_tree;
@@ -172,11 +172,11 @@ dissect_lan_destination(const u_char *pd, int offset, const char *type, proto_tr
   proto_tree *rd_tree;
   guint16 route_descriptor;
 
-  td = proto_tree_add_text(tree, NullTVB, offset, 8, "%s LAN destination",
+  td = proto_tree_add_text(tree, tvb, offset, 8, "%s LAN destination",
     			type);
   dest_tree = proto_item_add_subtree(td, ett_atm_lane_lc_lan_dest);
-  tag = pntohs(&pd[offset]);
-  proto_tree_add_text(dest_tree, NullTVB, offset, 2, "Tag: %s",
+  tag = tvb_get_ntohs(tvb, offset);
+  proto_tree_add_text(dest_tree, tvb, offset, 2, "Tag: %s",
 	val_to_str(tag, le_control_landest_tag_vals,
 				"Unknown (0x%04X)"));
   offset += 2;
@@ -184,20 +184,20 @@ dissect_lan_destination(const u_char *pd, int offset, const char *type, proto_tr
   switch (tag) {
 
   case TAG_MAC_ADDRESS:
-    proto_tree_add_text(dest_tree, NullTVB, offset, 6, "MAC address: %s",
-			ether_to_str((u_char *)&pd[offset]));
+    proto_tree_add_text(dest_tree, tvb, offset, 6, "MAC address: %s",
+			ether_to_str(tvb_get_ptr(tvb, offset, 6)));
     break;
 
   case TAG_ROUTE_DESCRIPTOR:
     offset += 4;
-    route_descriptor = pntohs(&pd[offset]);
-    trd = proto_tree_add_text(dest_tree, NullTVB, offset, 2, "Route descriptor: 0x%02X",
+    route_descriptor = tvb_get_ntohs(tvb, offset);
+    trd = proto_tree_add_text(dest_tree, tvb, offset, 2, "Route descriptor: 0x%02X",
     			route_descriptor);
     rd_tree = proto_item_add_subtree(td, ett_atm_lane_lc_lan_dest_rd);
-    proto_tree_add_text(rd_tree, NullTVB, offset, 2,
+    proto_tree_add_text(rd_tree, tvb, offset, 2,
 	    decode_numeric_bitfield(route_descriptor, 0xFFF0, 2*8,
 			"LAN ID = %u"));
-    proto_tree_add_text(rd_tree, NullTVB, offset, 2,
+    proto_tree_add_text(rd_tree, tvb, offset, 2,
 	    decode_numeric_bitfield(route_descriptor, 0x000F, 2*8,
 			"Bridge number = %u"));
     break;
@@ -245,10 +245,11 @@ static const value_string le_tlv_type_vals[] = {
 };
 
 static void
-dissect_le_control(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) 
+dissect_le_control(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 {
   proto_item *ti;
   proto_tree *lane_tree;
+  int offset = 0;
   proto_item *tf;
   proto_tree *flags_tree;
   proto_item *ttlv;
@@ -259,27 +260,27 @@ dissect_le_control(const u_char *pd, int offset, frame_data *fd, proto_tree *tre
   guint32 tlv_type;
   guint8 tlv_length;
 
-  if (check_col(fd, COL_INFO))
-    col_add_str(fd, COL_INFO, "LE Control");
+  if (check_col(pinfo->fd, COL_INFO))
+    col_add_str(pinfo->fd, COL_INFO, "LE Control");
 
   if (tree) {
-    ti = proto_tree_add_protocol_format(tree, proto_atm_lane, NullTVB, offset, 108, "ATM LANE");
+    ti = proto_tree_add_protocol_format(tree, proto_atm_lane, tvb, offset, 108, "ATM LANE");
     lane_tree = proto_item_add_subtree(ti, ett_atm_lane);
 
-    proto_tree_add_text(lane_tree, NullTVB, offset, 2, "Marker: 0x%04X",
-			pntohs(&pd[offset]));
+    proto_tree_add_text(lane_tree, tvb, offset, 2, "Marker: 0x%04X",
+			tvb_get_ntohs(tvb, offset));
     offset += 2;
 
-    proto_tree_add_text(lane_tree, NullTVB, offset, 1, "Protocol: 0x%02X",
-			pd[offset]);
+    proto_tree_add_text(lane_tree, tvb, offset, 1, "Protocol: 0x%02X",
+			tvb_get_guint8(tvb, offset));
     offset += 1;
 
-    proto_tree_add_text(lane_tree, NullTVB, offset, 1, "Version: 0x%02X",
-			pd[offset]);
+    proto_tree_add_text(lane_tree, tvb, offset, 1, "Version: 0x%02X",
+			tvb_get_guint8(tvb, offset));
     offset += 1;
 
-    opcode = pntohs(&pd[offset]);
-    proto_tree_add_text(lane_tree, NullTVB, offset, 2, "Opcode: %s",
+    opcode = tvb_get_ntohs(tvb, offset);
+    proto_tree_add_text(lane_tree, tvb, offset, 2, "Opcode: %s",
 	val_to_str(opcode, le_control_opcode_vals,
 				"Unknown (0x%04X)"));
     offset += 2;
@@ -291,80 +292,80 @@ dissect_le_control(const u_char *pd, int offset, frame_data *fd, proto_tree *tre
 
     if (opcode & 0x0100) {
       /* Response; decode status. */
-      proto_tree_add_text(lane_tree, NullTVB, offset, 2, "Status: %s",
-	val_to_str(pntohs(&pd[offset]), le_control_status_vals,
+      proto_tree_add_text(lane_tree, tvb, offset, 2, "Status: %s",
+	val_to_str(tvb_get_ntohs(tvb, offset), le_control_status_vals,
 				"Unknown (0x%04X)"));
     }
     offset += 2;
 
-    proto_tree_add_text(lane_tree, NullTVB, offset, 4, "Transaction ID: 0x%08X",
-    			pntohl(&pd[offset]));
+    proto_tree_add_text(lane_tree, tvb, offset, 4, "Transaction ID: 0x%08X",
+			tvb_get_ntohl(tvb, offset));
     offset += 4;
 
-    proto_tree_add_text(lane_tree, NullTVB, offset, 2, "Requester LECID: 0x%04X",
-    			pntohs(&pd[offset]));
+    proto_tree_add_text(lane_tree, tvb, offset, 2, "Requester LECID: 0x%04X",
+			tvb_get_ntohs(tvb, offset));
     offset += 2;
 
-    flags = pntohs(&pd[offset]);
-    tf = proto_tree_add_text(lane_tree, NullTVB, offset, 2, "Flags: 0x%04X",
-    			pntohs(&pd[offset]));
+    flags = tvb_get_ntohs(tvb, offset);
+    tf = proto_tree_add_text(lane_tree, tvb, offset, 2, "Flags: 0x%04X",
+			flags);
     flags_tree = proto_item_add_subtree(tf, ett_atm_lane_lc_flags);
-    proto_tree_add_text(flags_tree, NullTVB, offset, 2, "%s",
+    proto_tree_add_text(flags_tree, tvb, offset, 2, "%s",
 	decode_boolean_bitfield(flags, 0x0001, 8*2,
 				"Remote address", "Local address"));
-    proto_tree_add_text(flags_tree, NullTVB, offset, 2, "%s",
+    proto_tree_add_text(flags_tree, tvb, offset, 2, "%s",
 	decode_boolean_bitfield(flags, 0x0080, 8*2,
 				"Proxy", "Not proxy"));
-    proto_tree_add_text(flags_tree, NullTVB, offset, 2, "%s",
+    proto_tree_add_text(flags_tree, tvb, offset, 2, "%s",
 	decode_boolean_bitfield(flags, 0x0100, 8*2,
 				"Topology change", "No topology change"));
     offset += 2;
 
-    dissect_lan_destination(pd, offset, "Source", lane_tree);
+    dissect_lan_destination(tvb, offset, "Source", lane_tree);
     offset += 8;
 
-    dissect_lan_destination(pd, offset, "Target", lane_tree);
+    dissect_lan_destination(tvb, offset, "Target", lane_tree);
     offset += 8;
 
-    proto_tree_add_text(lane_tree, NullTVB, offset, 20, "Source ATM Address: %s",
-    			bytes_to_str(&pd[offset], 20));
+    proto_tree_add_text(lane_tree, tvb, offset, 20, "Source ATM Address: %s",
+			bytes_to_str(tvb_get_ptr(tvb, offset, 20), 20));
     offset += 20;
 
-    proto_tree_add_text(lane_tree, NullTVB, offset, 1, "LAN type: %s",
-	val_to_str(pd[offset], le_control_lan_type_vals,
+    proto_tree_add_text(lane_tree, tvb, offset, 1, "LAN type: %s",
+	val_to_str(tvb_get_guint8(tvb, offset), le_control_lan_type_vals,
 				"Unknown (0x%02X)"));
     offset += 1;
 
-    proto_tree_add_text(lane_tree, NullTVB, offset, 1, "Maximum frame size: %u",
-			pd[offset]);
+    proto_tree_add_text(lane_tree, tvb, offset, 1, "Maximum frame size: %u",
+			tvb_get_guint8(tvb, offset));
     offset += 1;
 
-    num_tlvs = pd[offset];
-    proto_tree_add_text(lane_tree, NullTVB, offset, 1, "Number of TLVs: %u",
+    num_tlvs = tvb_get_guint8(tvb, offset);
+    proto_tree_add_text(lane_tree, tvb, offset, 1, "Number of TLVs: %u",
 			num_tlvs);
     offset += 1;
 
-    proto_tree_add_text(lane_tree, NullTVB, offset, 1, "ELAN name size: %u",
-			pd[offset]);
+    proto_tree_add_text(lane_tree, tvb, offset, 1, "ELAN name size: %u",
+			tvb_get_guint8(tvb, offset));
     offset += 1;
 
-    proto_tree_add_text(lane_tree, NullTVB, offset, 20, "Target ATM Address: %s",
-    			bytes_to_str(&pd[offset], 20));
+    proto_tree_add_text(lane_tree, tvb, offset, 20, "Target ATM Address: %s",
+			bytes_to_str(tvb_get_ptr(tvb, offset, 20), 20));
     offset += 20;
 
-    proto_tree_add_text(lane_tree, NullTVB, offset, 32, "ELAN name: %s",
-    			bytes_to_str(&pd[offset], 32));
+    proto_tree_add_text(lane_tree, tvb, offset, 32, "ELAN name: %s",
+			bytes_to_str(tvb_get_ptr(tvb, offset, 32), 32));
     offset += 32;
 
     while (num_tlvs != 0) {
-      tlv_type = pntohl(&pd[offset]);
-      tlv_length = pd[offset+4];
-      ttlv = proto_tree_add_text(lane_tree, NullTVB, offset, 5+tlv_length, "TLV type: %s",
+      tlv_type = tvb_get_ntohl(tvb, offset);
+      tlv_length = tvb_get_guint8(tvb, offset+4);
+      ttlv = proto_tree_add_text(lane_tree, tvb, offset, 5+tlv_length, "TLV type: %s",
 	val_to_str(tlv_type, le_tlv_type_vals, "Unknown (0x%08x)"));
       tlv_tree = proto_item_add_subtree(ttlv, ett_atm_lane_lc_tlv);
-      proto_tree_add_text(tlv_tree, NullTVB, offset, 4, "TLV Type: %s",
+      proto_tree_add_text(tlv_tree, tvb, offset, 4, "TLV Type: %s",
 	val_to_str(tlv_type, le_tlv_type_vals, "Unknown (0x%08x)"));
-      proto_tree_add_text(tlv_tree, NullTVB, offset+4, 1, "TLV Length: %u", tlv_length);
+      proto_tree_add_text(tlv_tree, tvb, offset+4, 1, "TLV Length: %u", tlv_length);
       offset += 5+tlv_length;
       num_tlvs--;
     }
@@ -372,47 +373,47 @@ dissect_le_control(const u_char *pd, int offset, frame_data *fd, proto_tree *tre
 }
 
 static void
-dissect_lane(const union wtap_pseudo_header *pseudo_header, const u_char *pd,
-		int offset, frame_data *fd, proto_tree *tree) 
+dissect_lane(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) 
 {
   tvbuff_t	*next_tvb;
   tvbuff_t	*next_tvb_le_client;
 
+  pinfo->current_proto = "ATM LANE";
 
-  if (check_col(fd, COL_PROTOCOL))
-    col_add_str(fd, COL_PROTOCOL, "ATM LANE");
-  if (check_col(fd, COL_INFO))
-    col_add_str(fd, COL_INFO, "ATM LANE");
+  if (check_col(pinfo->fd, COL_PROTOCOL))
+    col_add_str(pinfo->fd, COL_PROTOCOL, "ATM LANE");
+  if (check_col(pinfo->fd, COL_INFO))
+    col_add_str(pinfo->fd, COL_INFO, "ATM LANE");
 
   /* Is it LE Control, 802.3, 802.5, or "none of the above"? */
-  switch (pseudo_header->ngsniffer_atm.AppHLType) {
+  switch (pinfo->pseudo_header->ngsniffer_atm.AppHLType) {
 
   case AHLT_LANE_LE_CTRL:
-    dissect_le_control(pd, offset, fd, tree);
+    dissect_le_control(tvb, pinfo, tree);
     break;
 
   case AHLT_LANE_802_3:
   case AHLT_LANE_802_3_MC:
-    dissect_le_client(pd, offset, fd, tree);
+    dissect_le_client(tvb, pinfo, tree);
 
     /* Dissect as Ethernet */
-    next_tvb_le_client	= tvb_new_subset(pi.compat_top_tvb, offset+2, -1, -1);
-    dissect_eth(next_tvb_le_client, &pi, tree);
+    next_tvb_le_client	= tvb_new_subset(tvb, 2, -1, -1);
+    dissect_eth(next_tvb_le_client, pinfo, tree);
     break;
 
   case AHLT_LANE_802_5:
   case AHLT_LANE_802_5_MC:
-    dissect_le_client(pd, offset, fd, tree);
+    dissect_le_client(tvb, pinfo, tree);
 
     /* Dissect as Token-Ring */
-    next_tvb_le_client	= tvb_new_subset(pi.compat_top_tvb, offset+2, -1, -1);
-    dissect_tr(next_tvb_le_client, &pi, tree);
+    next_tvb_le_client	= tvb_new_subset(tvb, 2, -1, -1);
+    dissect_tr(next_tvb_le_client, pinfo, tree);
     break;
 
   default:
     /* Dump it as raw data. */
-    next_tvb		= tvb_new_subset(pi.compat_top_tvb, offset,   -1, -1);
-    dissect_data_tvb(next_tvb, &pi, tree);
+    next_tvb		= tvb_new_subset(tvb, 0, -1, -1);
+    dissect_data_tvb(next_tvb, pinfo, tree);
     break;
   }
 }
@@ -485,21 +486,22 @@ static const value_string ipsilon_type_vals[] = {
  * We at least know it's AAL5....
  */
 static void
-atm_guess_content(union wtap_pseudo_header *pseudo_header, const u_char *pd,
-    frame_data *fd)
+atm_guess_content(tvbuff_t *tvb, packet_info *pinfo)
 {
-	if (pseudo_header->ngsniffer_atm.Vpi == 0) {
+	guint8 byte0, byte1, byte2;
+
+	if (pinfo->pseudo_header->ngsniffer_atm.Vpi == 0) {
 		/*
 		 * Traffic on some PVCs with a VPI of 0 and certain
 		 * VCIs is of particular types.
 		 */
-		switch (pseudo_header->ngsniffer_atm.Vci) {
+		switch (pinfo->pseudo_header->ngsniffer_atm.Vci) {
 
 		case 5:
 			/*
 			 * Signalling AAL.
 			 */
-			pseudo_header->ngsniffer_atm.AppTrafType =
+			pinfo->pseudo_header->ngsniffer_atm.AppTrafType =
 			    ATT_AAL_SIGNALLING;
 			return;
 
@@ -507,7 +509,7 @@ atm_guess_content(union wtap_pseudo_header *pseudo_header, const u_char *pd,
 			/*
 			 * ILMI.
 			 */
-			pseudo_header->ngsniffer_atm.AppTrafType |=
+			pinfo->pseudo_header->ngsniffer_atm.AppTrafType |=
 			    ATT_HL_ILMI;
 			return;
 		}
@@ -517,22 +519,25 @@ atm_guess_content(union wtap_pseudo_header *pseudo_header, const u_char *pd,
 	 * OK, we can't tell what it is based on the VPI/VCI; try
 	 * guessing based on the contents.
 	 */
-	if (pd[0] == 0xaa && pd[1] == 0xaa && pd[2] == 0x03) {
+	byte0 = tvb_get_guint8(tvb, 0);
+	byte1 = tvb_get_guint8(tvb, 1);
+	byte2 = tvb_get_guint8(tvb, 2);
+	if (byte0 == 0xaa && byte1 == 0xaa && byte2 == 0x03) {
 		/*
 		 * Looks like a SNAP header; assume it's LLC multiplexed
 		 * RFC 1483 traffic.
 		 */
-		pseudo_header->ngsniffer_atm.AppTrafType |= ATT_HL_LLCMX;
+		pinfo->pseudo_header->ngsniffer_atm.AppTrafType |= ATT_HL_LLCMX;
 	} else {
 		/*
 		 * Assume it's LANE.
 		 */
-		pseudo_header->ngsniffer_atm.AppTrafType |= ATT_HL_LANE;
-		if (pd[0] == 0xff && pd[1] == 0x00) {
+		pinfo->pseudo_header->ngsniffer_atm.AppTrafType |= ATT_HL_LANE;
+		if (byte0 == 0xff && byte1 == 0x00) {
 			/*
 			 * Looks like LE Control traffic.
 			 */
-			pseudo_header->ngsniffer_atm.AppHLType =
+			pinfo->pseudo_header->ngsniffer_atm.AppHLType =
 			    AHLT_LANE_LE_CTRL;
 		} else {
 			/*
@@ -543,28 +548,29 @@ atm_guess_content(union wtap_pseudo_header *pseudo_header, const u_char *pd,
 			 * still be situations where the user has to
 			 * tell us.
 			 */
-			pseudo_header->ngsniffer_atm.AppHLType =
+			pinfo->pseudo_header->ngsniffer_atm.AppHLType =
 			    AHLT_LANE_802_3;
 		}
 	}
 }
 
 void
-dissect_atm(union wtap_pseudo_header *pseudo_header, const u_char *pd,
-		frame_data *fd, proto_tree *tree) 
+dissect_atm(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 {
-  int        offset = 0;
-  proto_tree *atm_tree;
-  proto_item *ti;
-  guint       aal_type;
-  guint       hl_type;
-  tvbuff_t*   next_tvb;
+  proto_tree   *atm_tree;
+  proto_item   *ti;
+  guint         aal_type;
+  guint         hl_type;
+  const guint8 *pd;
+  int           offset;
+
+  pinfo->current_proto = "ATM";
 
-  aal_type = pseudo_header->ngsniffer_atm.AppTrafType & ATT_AALTYPE;
-  hl_type = pseudo_header->ngsniffer_atm.AppTrafType & ATT_HLTYPE;
+  aal_type = pinfo->pseudo_header->ngsniffer_atm.AppTrafType & ATT_AALTYPE;
+  hl_type = pinfo->pseudo_header->ngsniffer_atm.AppTrafType & ATT_HLTYPE;
   if (aal_type == ATT_AAL5) {
     if (hl_type == ATT_HL_UNKNOWN ||
-	pseudo_header->ngsniffer_atm.AppHLType == AHLT_UNKNOWN) {
+	pinfo->pseudo_header->ngsniffer_atm.AppHLType == AHLT_UNKNOWN) {
       /*
        * The joys of a connection-oriented link layer; the type of
        * traffic may be implied by the connection on which it's
@@ -585,106 +591,106 @@ dissect_atm(union wtap_pseudo_header *pseudo_header, const u_char *pd,
        * by which the user can specify what sort of traffic is on a
        * particular circuit.
        */
-      atm_guess_content(pseudo_header, pd, fd);
+      atm_guess_content(tvb, pinfo);
 
       /*
        * OK, now get the AAL type and high-layer type again.
        */
-      aal_type = pseudo_header->ngsniffer_atm.AppTrafType & ATT_AALTYPE;
-      hl_type = pseudo_header->ngsniffer_atm.AppTrafType & ATT_HLTYPE;
+      aal_type = pinfo->pseudo_header->ngsniffer_atm.AppTrafType & ATT_AALTYPE;
+      hl_type = pinfo->pseudo_header->ngsniffer_atm.AppTrafType & ATT_HLTYPE;
     }
   }
 
-  if (check_col(fd, COL_PROTOCOL))
-    col_add_str(fd, COL_PROTOCOL, "ATM");
+  if (check_col(pinfo->fd, COL_PROTOCOL))
+    col_add_str(pinfo->fd, COL_PROTOCOL, "ATM");
 
-  switch (pseudo_header->ngsniffer_atm.channel) {
+  switch (pinfo->pseudo_header->ngsniffer_atm.channel) {
 
   case 0:
     /* Traffic from DCE to DTE. */
-    if (check_col(fd, COL_RES_DL_DST))
-      col_add_str(fd, COL_RES_DL_DST, "DTE");
-    if (check_col(fd, COL_RES_DL_SRC))
-      col_add_str(fd, COL_RES_DL_SRC, "DCE");
+    if (check_col(pinfo->fd, COL_RES_DL_DST))
+      col_add_str(pinfo->fd, COL_RES_DL_DST, "DTE");
+    if (check_col(pinfo->fd, COL_RES_DL_SRC))
+      col_add_str(pinfo->fd, COL_RES_DL_SRC, "DCE");
     break;
 
   case 1:
     /* Traffic from DTE to DCE. */
-    if (check_col(fd, COL_RES_DL_DST))
-      col_add_str(fd, COL_RES_DL_DST, "DCE");
-    if (check_col(fd, COL_RES_DL_SRC))
-      col_add_str(fd, COL_RES_DL_SRC, "DTE");
+    if (check_col(pinfo->fd, COL_RES_DL_DST))
+      col_add_str(pinfo->fd, COL_RES_DL_DST, "DCE");
+    if (check_col(pinfo->fd, COL_RES_DL_SRC))
+      col_add_str(pinfo->fd, COL_RES_DL_SRC, "DTE");
     break;
   }
 
-  if (check_col(fd, COL_INFO)) {
+  if (check_col(pinfo->fd, COL_INFO)) {
     if (aal_type == ATT_AAL5) {
-      col_add_fstr(fd, COL_INFO, "AAL5 %s",
+      col_add_fstr(pinfo->fd, COL_INFO, "AAL5 %s",
 		val_to_str(hl_type, aal5_hltype_vals,
 				"Unknown traffic type (%x)"));
     } else {
-      col_add_str(fd, COL_INFO,
+      col_add_str(pinfo->fd, COL_INFO,
 		val_to_str(aal_type, aal_vals, "Unknown AAL (%x)"));
     }
   }
 
   if (tree) {
-    ti = proto_tree_add_protocol_format(tree, proto_atm, NullTVB, 0, 0, "ATM");
+    ti = proto_tree_add_protocol_format(tree, proto_atm, tvb, 0, 0, "ATM");
     atm_tree = proto_item_add_subtree(ti, ett_atm);
 
-    proto_tree_add_text(atm_tree, NullTVB, 0, 0, "AAL: %s",
+    proto_tree_add_text(atm_tree, tvb, 0, 0, "AAL: %s",
 	val_to_str(aal_type, aal_vals, "Unknown AAL (%x)"));
     if (aal_type == ATT_AAL5) {
-      proto_tree_add_text(atm_tree, NullTVB, 0, 0, "Traffic type: %s",
+      proto_tree_add_text(atm_tree, tvb, 0, 0, "Traffic type: %s",
 	val_to_str(hl_type, aal5_hltype_vals, "Unknown AAL5 traffic type (%x)"));
       switch (hl_type) {
 
       case ATT_HL_LLCMX:
-        proto_tree_add_text(atm_tree, NullTVB, 0, 0, "LLC multiplexed traffic");
+        proto_tree_add_text(atm_tree, tvb, 0, 0, "LLC multiplexed traffic");
         break;
 
       case ATT_HL_VCMX:
-        proto_tree_add_text(atm_tree, NullTVB, 0, 0, "VC multiplexed traffic type: %s",
-		val_to_str(pseudo_header->ngsniffer_atm.AppHLType,
+        proto_tree_add_text(atm_tree, tvb, 0, 0, "VC multiplexed traffic type: %s",
+		val_to_str(pinfo->pseudo_header->ngsniffer_atm.AppHLType,
 			vcmx_type_vals, "Unknown VCMX traffic type (%x)"));
         break;
 
       case ATT_HL_LANE:
-        proto_tree_add_text(atm_tree, NullTVB, 0, 0, "LANE traffic type: %s",
-		val_to_str(pseudo_header->ngsniffer_atm.AppHLType,
+        proto_tree_add_text(atm_tree, tvb, 0, 0, "LANE traffic type: %s",
+		val_to_str(pinfo->pseudo_header->ngsniffer_atm.AppHLType,
 			lane_type_vals, "Unknown LANE traffic type (%x)"));
         break;
 
       case ATT_HL_IPSILON:
-        proto_tree_add_text(atm_tree, NullTVB, 0, 0, "Ipsilon traffic type: %s",
-		val_to_str(pseudo_header->ngsniffer_atm.AppHLType,
+        proto_tree_add_text(atm_tree, tvb, 0, 0, "Ipsilon traffic type: %s",
+		val_to_str(pinfo->pseudo_header->ngsniffer_atm.AppHLType,
 			ipsilon_type_vals, "Unknown Ipsilon traffic type (%x)"));
         break;
       }
     }
-    proto_tree_add_item(atm_tree, hf_atm_vpi, NullTVB, 0, 0,
-		pseudo_header->ngsniffer_atm.Vpi);
-    proto_tree_add_item(atm_tree, hf_atm_vci, NullTVB, 0, 0,
-		pseudo_header->ngsniffer_atm.Vci);
-    switch (pseudo_header->ngsniffer_atm.channel) {
+    proto_tree_add_item(atm_tree, hf_atm_vpi, tvb, 0, 0,
+		pinfo->pseudo_header->ngsniffer_atm.Vpi);
+    proto_tree_add_item(atm_tree, hf_atm_vci, tvb, 0, 0,
+		pinfo->pseudo_header->ngsniffer_atm.Vci);
+    switch (pinfo->pseudo_header->ngsniffer_atm.channel) {
 
     case 0:
       /* Traffic from DCE to DTE. */
-      proto_tree_add_text(atm_tree, NullTVB, 0, 0, "Channel: DCE->DTE");
+      proto_tree_add_text(atm_tree, tvb, 0, 0, "Channel: DCE->DTE");
       break;
 
     case 1:
       /* Traffic from DTE to DCE. */
-      proto_tree_add_text(atm_tree, NullTVB, 0, 0, "Channel: DTE->DCE");
+      proto_tree_add_text(atm_tree, tvb, 0, 0, "Channel: DTE->DCE");
       break;
 
     default:
       /* Sniffers shouldn't provide anything other than 0 or 1. */
-      proto_tree_add_text(atm_tree, NullTVB, 0, 0, "Channel: %u",
- 		pseudo_header->ngsniffer_atm.channel);
+      proto_tree_add_text(atm_tree, tvb, 0, 0, "Channel: %u",
+ 		pinfo->pseudo_header->ngsniffer_atm.channel);
       break;
     }
-    if (pseudo_header->ngsniffer_atm.cells != 0) {
+    if (pinfo->pseudo_header->ngsniffer_atm.cells != 0) {
       /*
        * If the cell count is 0, assume it means we don't know how
        * many cells it was.
@@ -696,15 +702,15 @@ dissect_atm(union wtap_pseudo_header *pseudo_header, const u_char *pd,
        * some other way of indicating whether we have the AAL5 trailer
        * information.
        */
-      proto_tree_add_text(atm_tree, NullTVB, 0, 0, "Cells: %u",
-		pseudo_header->ngsniffer_atm.cells);
+      proto_tree_add_text(atm_tree, tvb, 0, 0, "Cells: %u",
+		pinfo->pseudo_header->ngsniffer_atm.cells);
       if (aal_type == ATT_AAL5) {
-        proto_tree_add_text(atm_tree, NullTVB, 0, 0, "AAL5 U2U: %u",
-		pseudo_header->ngsniffer_atm.aal5t_u2u);
-        proto_tree_add_text(atm_tree, NullTVB, 0, 0, "AAL5 len: %u",
-		pseudo_header->ngsniffer_atm.aal5t_len);
-        proto_tree_add_text(atm_tree, NullTVB, 0, 0, "AAL5 checksum: 0x%08X",
-		pseudo_header->ngsniffer_atm.aal5t_chksum);
+        proto_tree_add_text(atm_tree, tvb, 0, 0, "AAL5 U2U: %u",
+		pinfo->pseudo_header->ngsniffer_atm.aal5t_u2u);
+        proto_tree_add_text(atm_tree, tvb, 0, 0, "AAL5 len: %u",
+		pinfo->pseudo_header->ngsniffer_atm.aal5t_len);
+        proto_tree_add_text(atm_tree, tvb, 0, 0, "AAL5 checksum: 0x%08X",
+		pinfo->pseudo_header->ngsniffer_atm.aal5t_chksum);
       }
     }
   }
@@ -712,7 +718,7 @@ dissect_atm(union wtap_pseudo_header *pseudo_header, const u_char *pd,
   switch (aal_type) {
 
   case ATT_AAL_SIGNALLING:
-    dissect_sscop(pd, offset, fd, tree);
+    dissect_sscop(tvb, pinfo, tree);
     break;
 
   case ATT_AAL5:
@@ -720,24 +726,24 @@ dissect_atm(union wtap_pseudo_header *pseudo_header, const u_char *pd,
 
     case ATT_HL_LLCMX:
       /* Dissect as WTAP_ENCAP_ATM_RFC1483 */
-      /* The ATM iptrace capture that we have hows LLC at this point,
+      /* The ATM iptrace capture that we have shows LLC at this point,
        * so that's what I'm calling */
-      next_tvb = tvb_new_subset(pi.compat_top_tvb, offset, -1, -1);
-      dissect_llc(next_tvb, &pi, tree);
+      dissect_llc(tvb, &pi, tree);
       break;
 
     case ATT_HL_LANE:
-      dissect_lane(pseudo_header, pd, offset, fd, tree);
+      dissect_lane(tvb, pinfo, tree);
       break;
 
     case ATT_HL_ILMI:
-      dissect_snmp_pdu(pd, offset, fd, tree, "ILMI", proto_ilmi, ett_ilmi);
+      tvb_compat(tvb, &pd, &offset);
+      dissect_snmp_pdu(pd, offset, pinfo->fd, tree, "ILMI", proto_ilmi, ett_ilmi);
       break;
 
     default:
       if (tree) {
         /* Dump it as raw data. */
-        dissect_data(pd, offset, fd, tree);
+        dissect_data_tvb(tvb, pinfo, tree);
         break;
       }
     }
@@ -746,7 +752,7 @@ dissect_atm(union wtap_pseudo_header *pseudo_header, const u_char *pd,
   default:
     if (tree) {
       /* Dump it as raw data.  (Is this a single cell?) */
-      dissect_data(pd, offset, fd, tree);
+      dissect_data_tvb(tvb, pinfo, tree);
     }
     break;
   }