flow: Add flow_sidx_valid() helper

To implement the TCP hash table, we need an invalid (NULL-like) value for
flow_sidx_t.  We use FLOW_SIDX_NONE for that, but for defensiveness, we
treat (usually) anything with an out of bounds flow index the same way.

That's not always done consistently though.  In flow_at_sidx() we open code
a check on the flow index.  In tcp_hash_probe() we instead compare against
FLOW_SIDX_NONE, and in some other places we use the fact that
flow_at_sidx() will return NULL in this case, even if we don't otherwise
need the flow it returns.

Clean this up a bit, by adding an explicit flow_sidx_valid() test function.

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

1 files changed, 1 insertions, 1 deletions

diff --git a/flow_table.h b/flow_table.h
index 1b16349..226ddbd 100644
--- a/flow_table.h
+++ b/flow_table.h
@@ -73,7 +73,7 @@ static inline unsigned flow_idx(const struct flow_common *f)
  */
 static inline union flow *flow_at_sidx(flow_sidx_t sidx)
 {
-	if (sidx.flow >= FLOW_MAX)
+	if (!flow_sidx_valid(sidx))
 		return NULL;
 	return FLOW(sidx.flow);
 }