Add to tvbuffs a "fragment length" field; if the tvbuff represents the

first fragment of a non-reassembled packet, and we know the length the
packet would have if it were reassembled, this field holds the length of
the fragment, and the "reported length" field shows the length the
packet would have if it were reassembled, so going past the end of the
fragment but staying within the length of the reassembled packet can be
reported as "dissection would have worked if the packet had been
reassembled" rather than "the packet is too short, so it was probably
malformed".

Add a FragmentBoundsError exception, thrown in the "dissection would
have worked if the packet had been reassembled" case.

Add a new tvb_new_subset_length_fragment() routine to create a new
subset tvb with specified fragment and reported lengths.  Use it in the
CLNP dissector.

Add some more sanity checks in the CLNP dissector.

svn path=/trunk/; revision=48917

1 files changed, 11 insertions, 0 deletions

diff --git a/epan/show_exception.c b/epan/show_exception.c
index ddc41bff85..641b86f786 100644
--- a/epan/show_exception.c
+++ b/epan/show_exception.c
@@ -84,6 +84,17 @@ show_exception(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
 		/* expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR, "Packet size limited");*/
 		break;
 
+	case FragmentBoundsError:
+		col_append_fstr(pinfo->cinfo, COL_INFO, "[Unreassembled Packet%s]", pinfo->noreassembly_reason);
+		/*item =*/ proto_tree_add_protocol_format(tree, proto_unreassembled,
+		    tvb, 0, 0, "[Unreassembled Packet%s: %s]",
+		    pinfo->noreassembly_reason, pinfo->current_proto);
+		/* Don't record FragmentBoundsError exceptions as expert events - they merely
+		 * reflect dissection done with reassembly turned off
+		 * (any case where it's caused by something else is a bug). */
+		/* expert_add_info_format(pinfo, item, PI_REASSEMBLE, PI_WARN, "Unreassembled Packet (Exception occured)");*/
+		break;
+
 	case ReportedBoundsError:
 		show_reported_bounds_error(tvb, pinfo, tree);
 		break;