Move the definition of the structure constructed for each SPX

transmission (and shared by all retransmissions), and passed to SPX
subdissectors, to "packet-ipx.h", and use the same structure in the SPX
dissector and the NDPS dissector.

Set up conversations and those structures without checking whether we've
seen the packet before or not; just check whether we find the
conversation before creating a new one, and check whether we find a
structure for the packet before creating a new one.  Pass it to the
subdissector regardless of whether we've seen the packet before or not,
and check it in the NDPS dissector regardless of whether we've seen it
before or not.

Don't store a "retransmission" flag in the structure - the initial
transmission and the retransmissions all share a single data structure,
but they don't all have the same value for the "retransmission" flag,
and you can tell whether a packet is a retransmission or not by
comparing its frame number with the frame number from the structure; if
they're different, it's a retransmission.

svn path=/trunk/; revision=7418

1 files changed, 74 insertions, 62 deletions

diff --git a/packet-ipx.c b/packet-ipx.c
index 657df6fd6f..2d295ae858 100644
--- a/packet-ipx.c
+++ b/packet-ipx.c
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 2000-2002 by Gilbert Ramirez.
  * Portions Copyright (c) Novell, Inc. 2002-2003
  *
- * $Id: packet-ipx.c,v 1.123 2003/04/08 00:39:27 guy Exp $
+ * $Id: packet-ipx.c,v 1.124 2003/04/08 02:00:53 guy Exp $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@ethereal.com>
@@ -354,14 +354,6 @@ typedef struct {
 	guint32		    spx_src;
 } spx_hash_key;
 
-typedef struct {
-        guint16             spx_seq;
-        guint16             spx_ack;
-        guint16             spx_all;
-        guint32             num;
-        gboolean            retransmission;
-} spx_hash_value;
-
 static GHashTable *spx_hash = NULL;
 static GMemChunk *spx_hash_keys = NULL;
 static GMemChunk *spx_hash_values = NULL;
@@ -406,8 +398,8 @@ spx_init_protocol(void)
 			SPX_PACKET_INIT_COUNT * sizeof(spx_hash_key),
 			G_ALLOC_ONLY);
 	spx_hash_values = g_mem_chunk_new("spx_hash_values",
-			sizeof(spx_hash_value),
-			SPX_PACKET_INIT_COUNT * sizeof(spx_hash_value),
+			sizeof(spx_info),
+			SPX_PACKET_INIT_COUNT * sizeof(spx_info),
 			G_ALLOC_ONLY);
 }
 
@@ -430,11 +422,11 @@ spx_postseq_cleanup(void)
 	 * needed during random-access processing of the proto_tree.*/
 }
 
-spx_hash_value*
+spx_info*
 spx_hash_insert(conversation_t *conversation, guint32 spx_src)
 {
 	spx_hash_key		*key;
-	spx_hash_value		*value;
+	spx_info		*value;
 
 	/* Now remember the packet, so we can find it if we later. */
 	key = g_mem_chunk_alloc(spx_hash_keys);
@@ -446,7 +438,6 @@ spx_hash_insert(conversation_t *conversation, guint32 spx_src)
 	value->spx_ack = 0;
 	value->spx_all = 0;
 	value->num = 0;
-	value->retransmission = FALSE;
        
 	g_hash_table_insert(spx_hash, key, value);
 
@@ -454,7 +445,7 @@ spx_hash_insert(conversation_t *conversation, guint32 spx_src)
 }
 
 /* Returns the spx_rec*, or NULL if not found. */
-spx_hash_value*
+spx_info*
 spx_hash_lookup(conversation_t *conversation, guint32 spx_src)
 {
 	spx_hash_key		key;
@@ -520,7 +511,7 @@ dissect_spx(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 	const char	*spx_msg_string;
 	guint16		low_socket, high_socket;
 	guint32		src;
-	spx_hash_value	*pkt_value = NULL;
+	spx_info	*pkt_value = NULL;
 	conversation_t	*conversation = NULL;
 
 	if (check_col(pinfo->cinfo, COL_PROTOCOL))
@@ -555,56 +546,70 @@ dissect_spx(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 		proto_tree_add_item(spx_tree, hf_spx_ack_nr, tvb,  8, 2, FALSE);
 		proto_tree_add_item(spx_tree, hf_spx_all_nr, tvb, 10, 2, FALSE);
 	}
-	src = tvb_get_ntohs(tvb, 0)+tvb_get_ntohs(tvb, 2)+tvb_get_ntohs(tvb, 4)+tvb_get_ntohs(tvb, 6)+tvb_get_ntohs(tvb, 8);
-	/* SPX is Connection Oriented and Delivery Guaranteed
-	 *  We need to flag retransmissions by the SPX protocol
+
+	/*
+	 * SPX is Connection Oriented and Delivery Guaranteed.
+	 * We need to flag retransmissions by the SPX protocol, so that
+	 * subdissectors know whether a packet was retransmitted.
+	 *
+	 * We start out by creating a conversation for this IPX session.
+	 * XXX - should we be using "pinfo->srcport" twice, or
+	 * "pinfo->srcport" and "pinfo->destport"?  For that matter, should
+	 * we just be using PT_IPX, and get rid of PT_NCP?
 	 */
-	if (!pinfo->fd->flags.visited) {
-		conversation = find_conversation(&pinfo->src, &pinfo->dst,
+	conversation = find_conversation(&pinfo->src, &pinfo->dst,
+	    PT_NCP, pinfo->srcport, pinfo->srcport, 0);
+	if (conversation == NULL) {
+		/*
+		 * It's not part of any conversation - create a new one.
+		 */
+		conversation = conversation_new(&pinfo->src, &pinfo->dst,
 		    PT_NCP, pinfo->srcport, pinfo->srcport, 0);
-    
-		if (conversation == NULL) {
-			/*
-			 * It's not part of any conversation - create a new
-			 * one.
-			 */
-			conversation = conversation_new(&pinfo->src,
-			    &pinfo->dst, PT_NCP, pinfo->srcport,
-			    pinfo->srcport, 0);
-			pkt_value = spx_hash_insert(conversation, src);
-			pkt_value->spx_seq = tvb_get_ntohs(tvb, 6);
-			pkt_value->spx_ack = tvb_get_ntohs(tvb, 8);
-			pkt_value->spx_all = tvb_get_ntohs(tvb, 10);
-			pkt_value->num = pinfo->fd->num;
-			pkt_value->retransmission = FALSE;
-		} else {
-			pkt_value = spx_hash_lookup(conversation, src);
-			if (pkt_value &&
-			    tvb_reported_length_remaining(tvb, SPX_HEADER_LEN) > 0) {
-				if (check_col(pinfo->cinfo, COL_INFO)) {
-					col_add_fstr(pinfo->cinfo, COL_INFO,
-					"[Retransmission] Original Packet %u",
-					pkt_value->num);
-				}
-				pkt_value->spx_seq = tvb_get_ntohs(tvb, 6);
-				pkt_value->spx_ack = tvb_get_ntohs(tvb, 8);
-				pkt_value->spx_all = tvb_get_ntohs(tvb, 10);
-				pkt_value->retransmission = TRUE;
-			} else {
-				pkt_value = spx_hash_insert(conversation, src);
-				pkt_value->spx_seq = tvb_get_ntohs(tvb, 6);
-				pkt_value->spx_ack = tvb_get_ntohs(tvb, 8);
-				pkt_value->spx_all = tvb_get_ntohs(tvb, 10);
-				pkt_value->num = pinfo->fd->num;
-				pkt_value->retransmission = FALSE;
-			}
-		}
+	}
+
+	/*
+	 * Now we'll hash the SPX header and use the result of that,
+	 * plus the conversation, as a hash key to identify this packet,
+	 * and, if it's not already in the SPX packet hash table, enter
+	 * it into that hash table so we can detect retransmissions.
+	 *
+	 * On the first pass, if we don't find it in the hash table, it's
+	 * not a retransmission, otherwise it is.  If we don't find it,
+	 * we enter it into the hash table, with the frame number.
+	 *
+	 * On subsequent passes, we should find it in the frame table
+	 * whether it's a retransmission or not; it's a retransmission
+	 * iff the frame number doesn't match the frame number in the
+	 * hash table.
+	 */
+	src = tvb_get_ntohs(tvb, 0)+tvb_get_ntohs(tvb, 2)+tvb_get_ntohs(tvb, 4)+tvb_get_ntohs(tvb, 6)+tvb_get_ntohs(tvb, 8);
+	pkt_value = spx_hash_lookup(conversation, src);
+	if (pkt_value == NULL) {
 		/*
-		 * Store the spx info so that subidissectors know what this
-		 * is.
-		 * Note: num will equal retransmitted source packet number.
+		 * Not found in the hash table.
+		 * Enter it into the hash table.
 		 */
-		pinfo->private_data = pkt_value;
+		pkt_value = spx_hash_insert(conversation, src);
+		pkt_value->spx_seq = tvb_get_ntohs(tvb, 6);
+		pkt_value->spx_ack = tvb_get_ntohs(tvb, 8);
+		pkt_value->spx_all = tvb_get_ntohs(tvb, 10);
+		pkt_value->num = pinfo->fd->num;
+	}
+
+	/*
+	 * It's a retransmission iff the frame number in the hash table
+	 * entry (which is the frame number of the original transmission)
+	 * isn't the frame number of this frame.
+	 *
+	 * XXX - put something into the protocol tree as well?
+	 * If so, give the frame number, as an FT_FRAMENUM.
+	 */
+	if (pkt_value->num != pinfo->fd->num) {
+		if (check_col(pinfo->cinfo, COL_INFO)) {
+			col_add_fstr(pinfo->cinfo, COL_INFO,
+			    "[Retransmission] Original Packet %u",
+			    pkt_value->num);
+		}
 	}
 
 	if (tvb_reported_length_remaining(tvb, SPX_HEADER_LEN) > 0) {
@@ -631,6 +636,13 @@ dissect_spx(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 			high_socket = pinfo->destport;
 		}
 
+		/*
+		 * Pass the SPX info to subdissectors, so that they know
+		 * what this is.
+		 * Note: num will equal retransmitted source packet number.
+		 */
+		pinfo->private_data = pkt_value;
+
 		next_tvb = tvb_new_subset(tvb, SPX_HEADER_LEN, -1, -1);
 		if (dissector_try_port(spx_socket_dissector_table, low_socket,
 		    next_tvb, pinfo, tree))