In "ethertype()", catch exceptions from the dissector we call, and, if

we get an exception, add in any trailer we and then rethrow the
exception, so that the trailer will be put into the tree even if some
subdissector threw an exception.  (Yes, an exception can be thrown even
in a frame with a trailer; you could have a frame, all of which was
captured, that has an IP datagram containing a UDP datagram, and if the
UDP payload isn't big enough for the type of packet it's supposed to be,
a ReportedBoundsError exception can be thrown.)

svn path=/trunk/; revision=2917

1 files changed, 62 insertions, 12 deletions

diff --git a/packet-ethertype.c b/packet-ethertype.c
index ffe3682fb3..d89980a6ba 100644
--- a/packet-ethertype.c
+++ b/packet-ethertype.c
@@ -1,7 +1,7 @@
 /* ethertype.c
  * Routines for calling the right protocol for the ethertype.
  *
- * $Id: packet-ethertype.c,v 1.10 2001/01/18 07:44:39 guy Exp $
+ * $Id: packet-ethertype.c,v 1.11 2001/01/18 08:38:10 guy Exp $
  *
  * Gilbert Ramirez <gram@xiexie.org>
  *
@@ -72,6 +72,9 @@ const value_string etype_vals[] = {
     {ETHERTYPE_DEC_SCA,		"DEC LAVC/SCA"			},
     {0,				NULL				} };
 
+static void add_trailer(proto_tree *fh_tree, int trailer_id, tvbuff_t *tvb,
+    tvbuff_t *next_tvb, int offset_after_etype, guint length_before);
+
 void
 capture_ethertype(guint16 etype, int offset,
 		const u_char *pd, packet_counts *ld)
@@ -100,10 +103,10 @@ ethertype(guint16 etype, tvbuff_t *tvb, int offset_after_etype,
 		packet_info *pinfo, proto_tree *tree, proto_tree *fh_tree,
 		int etype_id, int trailer_id)
 {
-	char		*description;
-	tvbuff_t	*next_tvb;
-	guint		length_before, length;
-	tvbuff_t	*volatile trailer_tvb;
+	char			*description;
+	tvbuff_t		*next_tvb;
+	guint			length_before;
+	volatile gboolean	dissector_found;
 	
 	/* Add to proto_tree */
 	if (tree) {
@@ -117,35 +120,82 @@ ethertype(guint16 etype, tvbuff_t *tvb, int offset_after_etype,
 	/* Remember how much data there is in it. */
 	length_before = tvb_reported_length(next_tvb);
 
-	/* Look for sub-dissector */
-	if (!dissector_try_port(ethertype_dissector_table, etype,
-	    next_tvb, pinfo, tree)) {
+	/* Look for sub-dissector, and call it if found.
+	   Catch BoundsError and ReportedBoundsError, so that if the
+	   reported length of "next_tvb" was reduced by some dissector
+	   before an exception was thrown, we can still put in an item
+	   for the trailer. */
+	TRY {
+		dissector_found = dissector_try_port(ethertype_dissector_table,
+		    etype, next_tvb, pinfo, tree);
+	}
+	CATCH2(BoundsError, ReportedBoundsError) {
+		/* Well, somebody threw an exception; that means that a
+		   dissector was found, so we don't need to dissect
+		   the payload as data or update the protocol or info
+		   columns. */
+		dissector_found = TRUE;
+
+		/* Add the trailer, if appropriate. */
+		add_trailer(fh_tree, trailer_id, tvb, next_tvb,
+		    offset_after_etype, length_before);
+
+		/* Rrethrow the exception, so the "Short Frame" or "Mangled
+		   Frame" indication can be put into the tree. */
+		RETHROW;
+
+		/* XXX - RETHROW shouldn't return. */
+		g_assert_not_reached();
+	}
+	ENDTRY;
+
+	if (!dissector_found) {
 		/* No sub-dissector found.
 		   Label rest of packet as "Data" */
 		dissect_data(next_tvb, 0, pinfo, tree);
 
 		/* Label protocol */
-		switch(etype) {
+		switch (etype) {
 
 		case ETHERTYPE_LOOP:
 			if (check_col(pinfo->fd, COL_PROTOCOL)) {
 				col_add_fstr(pinfo->fd, COL_PROTOCOL, "LOOP");
 			}
 			break;
+
 		default:
 			if (check_col(pinfo->fd, COL_PROTOCOL)) {
-				col_add_fstr(pinfo->fd, COL_PROTOCOL, "0x%04x", etype);
+				col_add_fstr(pinfo->fd, COL_PROTOCOL, "0x%04x",
+				    etype);
 			}
 			break;
 		}
 		if (check_col(pinfo->fd, COL_INFO)) {
 			description = match_strval(etype, etype_vals);
 			if (description) {
-				col_add_fstr(pinfo->fd, COL_INFO, "%s", description);
+				col_add_fstr(pinfo->fd, COL_INFO, "%s",
+				    description);
 			}
 		}
 	}
 
+	add_trailer(fh_tree, trailer_id, tvb, next_tvb, offset_after_etype,
+	    length_before);
+}
+
+static void
+add_trailer(proto_tree *fh_tree, int trailer_id, tvbuff_t *tvb,
+    tvbuff_t *next_tvb, int offset_after_etype, guint length_before)
+{
+	guint		length;
+	tvbuff_t	*volatile trailer_tvb;
+
+	if (fh_tree == NULL)
+		return;	/* we're not building a protocol tree */
+
+	if (trailer_id == -1)
+		return;	/* our caller doesn't care about trailers */
+
 	/* OK, how much is there in that tvbuff now? */
 	length = tvb_reported_length(next_tvb);
 
@@ -170,7 +220,7 @@ ethertype(guint16 etype, tvbuff_t *tvb, int offset_after_etype,
 
 	/* If there's some bytes left over, and we were given an item ID
 	   for a trailer, mark those bytes as a trailer. */
-	if (trailer_tvb && tree && trailer_id != -1) {
+	if (trailer_tvb) {
 		guint	trailer_length;
 
 		trailer_length = tvb_length(trailer_tvb);