Make a "tcp_dissect_pdus()" with the standard loop for a TCP segment,

extracting PDUs from it and possibly doing reassembly.  Make the COPS,
DNS, DSI, Gryphon, and SCCP dissectors use it.

Add "set_actual_length()", "tcp_dissect_pdus()",
"decode_boolean_bitfield()", "decode_numeric_bitfield()", and
"decode_enumerated_bitfield()" to the list of routines available to
dissectors on platforms where routines in the main program aren't
available to dynamically-loaded code.

Declare routines in "to_str.h" as "extern"; as I remember, that's
necessary to allow the "decode_XXX_bitfield()" routines declared therein
to be made available to plugins as per the above.

Note that new exported routines should be added to the end of the table
if that's the only change being made to the table.

Create a new "plugin_api_decls.h" header file, used to declare both the
"p_" variables and the "p_" structure members in the routine-exporting
mechanism; this reduces the number of places you have to change to
change the list of exported routines.

svn path=/trunk/; revision=5394

1 files changed, 21 insertions, 102 deletions

diff --git a/packet-skinny.c b/packet-skinny.c
index 7933827819..663bd5fb9e 100644
--- a/packet-skinny.c
+++ b/packet-skinny.c
@@ -11,7 +11,7 @@
  * This file is based on packet-aim.c, which is
  * Copyright 2000, Ralf Hoelzer <ralf@well.com>
  *
- * $Id: packet-skinny.c,v 1.17 2002/03/27 20:29:05 guy Exp $
+ * $Id: packet-skinny.c,v 1.18 2002/05/05 00:16:32 guy Exp $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@ethereal.com>
@@ -45,7 +45,7 @@
 #include <epan/packet.h>
 #include "prefs.h"
 
-#include "packet-frame.h"
+#include "packet-tcp.h"
 
 #define TCP_PORT_SKINNY 2000
 
@@ -828,6 +828,23 @@ static gboolean skinny_desegment = TRUE;
 
 static dissector_handle_t data_handle;
 
+/* Get the length of a single SCCP PDU */
+static guint get_skinny_pdu_len(tvbuff_t *tvb, int offset)
+{
+  guint32 hdr_data_length;
+
+  /*
+   * Get the length of the SCCP packet.
+   */
+  hdr_data_length = tvb_get_letohl(tvb, offset);
+
+  /*
+   * That length doesn't include the length of the header itself;
+   * add that in.
+   */
+  return hdr_data_length + 8;
+}
+
 /* Dissect a single SCCP PDU */
 static void dissect_skinny_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 {
@@ -1446,12 +1463,6 @@ static void dissect_skinny(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
   /* The general structure of a packet: {IP-Header|TCP-Header|n*SKINNY}
    * SKINNY-Packet: {Header(Size, Reserved)|Data(MessageID, Message-Data)}
    */
-  
-  volatile int offset = 0;
-  int length_remaining;
-  int length;
-  tvbuff_t *next_tvb;
-
   /* Header fields */
   volatile guint32 hdr_data_length;
   guint32 hdr_reserved;
@@ -1480,100 +1491,8 @@ static void dissect_skinny(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
     col_set_str(pinfo->cinfo, COL_INFO, "Skinny Client Control Protocol");
   }
   
-  while (tvb_reported_length_remaining(tvb, offset) != 0) {
-    length_remaining = tvb_length_remaining(tvb, offset);
-
-    /*
-     * Can we do reassembly?
-     */
-    if (skinny_desegment && pinfo->can_desegment) {
-      /*
-       * Yes - is the length field in the SCCP header split across
-       * segment boundaries?
-       */
-      if (length_remaining < 4) {
-	/*
-	 * Yes.  Tell the TCP dissector where the data for this message
-	 * starts in the data it handed us, and how many more bytes we
-	 * need, and return.
-	 */
-	pinfo->desegment_offset = offset;
-	pinfo->desegment_len = 4 - length_remaining;
-	return;
-      }
-    }
-
-    /*
-     * Get the length of the SCCP packet.
-     */
-    hdr_data_length = tvb_get_letohl(tvb, offset);
-
-    /*
-     * Can we do reassembly?
-     */
-    if (skinny_desegment && pinfo->can_desegment) {
-      /*
-       * Yes - is the SCCP packet split across segment boundaries?
-       */
-      if ((guint32)length_remaining < hdr_data_length + 8) {
-	/*
-	 * Yes.  Tell the TCP dissector where the data for this message
-	 * starts in the data it handed us, and how many more bytes we
-	 * need, and return.
-	 */
-	pinfo->desegment_offset = offset;
-	pinfo->desegment_len = (hdr_data_length + 8) - length_remaining;
-	return;
-      }
-    }
-
-    /*
-     * Construct a tvbuff containing the amount of the payload we have
-     * available.  Make its reported length the amount of data in the
-     * SCCP packet.
-     *
-     * XXX - if reassembly isn't enabled. the subdissector will throw a
-     * BoundsError exception, rather than a ReportedBoundsError exception.
-     * We really want a tvbuff where the length is "length", the reported
-     * length is "hdr_data_length + 8", and the "if the snapshot length
-     * were infinite" length is the minimum of the reported length of
-     * the tvbuff handed to us and "hdr_data_length + 8", with a new type
-     * of exception thrown if the offset is within the reported length but
-     * beyond that third length, with that exception getting the
-     * "Unreassembled Packet" error.
-     */
-    length = length_remaining;
-    if ((guint32)length > hdr_data_length + 8)
-      length = hdr_data_length + 8;
-    next_tvb = tvb_new_subset(tvb, offset, length, hdr_data_length + 8);
-
-    /*
-     * Dissect the SCCP packet.
-     *
-     * Catch the ReportedBoundsError exception; if this particular message
-     * happens to get a ReportedBoundsError exception, that doesn't mean
-     * that we should stop dissecting SCCP messages within this frame or
-     * chunk of reassembled data.
-     *
-     * If it gets a BoundsError, we can stop, as there's nothing more to
-     * see, so we just re-throw it.
-     */
-    TRY {
-      dissect_skinny_pdu(next_tvb, pinfo, tree);
-    }
-    CATCH(BoundsError) {
-      RETHROW;
-    }
-    CATCH(ReportedBoundsError) {
-      show_reported_bounds_error(tvb, pinfo, tree);
-    }
-    ENDTRY;
-
-    /*
-     * Skip the SCCP header and the payload.
-     */
-    offset += hdr_data_length + 8;
-  }
+  tcp_dissect_pdus(tvb, pinfo, tree, skinny_desegment, 4,
+	get_skinny_pdu_len, dissect_skinny_pdu);
 }
 
 /* Register the protocol with Ethereal */