Add code to check the checksums of TCP segments and UDP datagrams;

replace the existing checksummer with a modified version of the BSD
checksumming code.  Add a flag to the "packet_info" structure to
indicate that a packet is the first fragment of a fragmented datagram,
so that the checksummers won't try to checksum those.

(It doesn't seem to add a lot of CPU overhead, so we don't introduce a
flag to disable it, yet.  Further checks may be necessary to see whether
the overhead is just swamped by other overheads when scanning through a
capture dissecting all frames, or if it truly is negligible.)

Make the Boolean preference option controlling whether to make the
top-level protocol tree item for TCP display a packet summary static to
the TCP dissector (it doesn't need to be accessible outside the TCP
dissector).

svn path=/trunk/; revision=2751

1 files changed, 14 insertions, 0 deletions

diff --git a/in_cksum.h b/in_cksum.h
new file mode 100644
index 0000000000..66cbcc4a91
--- /dev/null
+++ b/in_cksum.h
@@ -0,0 +1,14 @@
+/* in_cksum.h
+ * Declaration of  Internet checksum routine.
+ *
+ * $Id: in_cksum.h,v 1.1 2000/12/13 02:24:22 guy Exp $
+ */
+
+typedef struct {
+	const guint8 *ptr;
+	int	len;
+} vec_t;
+
+extern int in_cksum(const vec_t *vec, int veclen);
+
+extern guint16 in_cksum_shouldbe(guint16 sum, guint16 computed_sum);