When we're dissecting the beginning of a fragmented packet that we

haven't reassembled, we're probably moving sequentially through the
packet, which means that we'll run past the end of the fragment rather
than past the end of what would have been the reassembled packet had we
reassembled it.

I.e., there's little reason to care whether we're past the end of the
fragment but not past the end of the packet, or whether we're past the
end of the packet; in either case, we're past the end of the fragment,
and if somebody wants to know whether the packet is malformed by
stopping short of certain fields, they should enable reassembly.

So we get rid of the explicit fragment length in tvbuffs and, instead,
have a "this is a fragment" flag; if that flag is set, we throw
FragmentBoundsError rather than ReportedBoundsError if we run past the
end of the reported data.

(This also means we could flag the tvbuff even if we don't know how
large the reassembled packet will be, e.g. when doing IP reassembly.)

Replace tvb_new_subset_length_fragment() with tvb_new_subset_length()
and a new "set the "this is a fragment flag"" routine.

svn path=/trunk/; revision=48940

1 files changed, 6 insertions, 6 deletions

diff --git a/epan/tvbuff-int.h b/epan/tvbuff-int.h
index 33057bdd87..6f7e9818a0 100644
--- a/epan/tvbuff-int.h
+++ b/epan/tvbuff-int.h
@@ -48,6 +48,11 @@ typedef struct {
 
 } tvb_comp_t;
 
+/*
+ * Tvbuff flags.
+ */
+#define TVBUFF_FRAGMENT		0x00000001	/* this is a fragment */
+
 struct tvbuff {
 	/* Doubly linked list pointers */
 	tvbuff_t                *next;
@@ -56,6 +61,7 @@ struct tvbuff {
 	/* Record-keeping */
 	tvbuff_type		type;
 	gboolean		initialized;
+	guint			flags;
 	struct tvbuff		*ds_tvb;  /**< data source top-level tvbuff */
 
 	/** TVBUFF_SUBSET and TVBUFF_COMPOSITE keep track
@@ -79,12 +85,6 @@ struct tvbuff {
 	/** Reported length. */
 	guint			reported_length;
 
-	/* If this tvbuff represents the first fragment of a larger packet
-	 * that was not reassembled, this is the length of the fragment
-	 * ("reported_length" will be the length of the full packet).
-	 */
-	guint			fragment_length;
-
 	/* Offset from beginning of first TVBUFF_REAL. */
 	gint			raw_offset;