tcp: Unify spliced and non-spliced connection tables

Currently spliced and non-spliced connections are stored in completely
separate tables, so there are completely independent limits on the number
of spliced and non-spliced connections.  This is a bit counter-intuitive.

More importantly, the fact that the tables are separate prevents us from
unifying some other logic between the two cases.  So, merge these two
tables into one, using the 'c.spliced' common field to distinguish between
them when necessary.

For now we keep a common limit of 128k connections, whether they're spliced
or non-spliced, which means we save memory overall.  If necessary we could
increase this to a 256k or higher total, which would cost memory but give
some more flexibility.

For now, the code paths which need to step through all extant connections
are still separate for the two cases, just skipping over entries which
aren't for them.  We'll improve that in later patches.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

tcp_conn.h

@@ -195,4 +195,10 @@ union tcp_conn {
 	struct tcp_splice_conn splice;
 };
 
+/* TCP connections */
+extern union tcp_conn tc[];
+
+void tcp_splice_conn_update(struct ctx *c, struct tcp_splice_conn *new);
+void tcp_table_compact(struct ctx *c, union tcp_conn *hole);
+
 #endif /* TCP_CONN_H */