[dpdk-dev] [PATCHv2 1/3] ACL: fix a problem in acl_merge_trie

[Konstantin Ananyev <konstantin.ananyev@intel.com>]

Reported by Zi Hu <huzilucky@gmail.com>:

"...
cat test_data/rule1
@192.168.0.0/24 192.168.0.0/24 400 : 500 0 : 52 6/0xff
@192.168.0.0/24 192.168.0.0/24 400 : 500 54 : 65280 6/0xff
@192.168.0.0/24 192.168.0.0/24 400 : 500 0 : 65535 6/0xff

cat test_data/trace1
0xc0a80005 0xc0a80009 450 53 0x06

I run the test by:
sudo ./testacl -n 2 -c 4 -- --rulesf=./test_data/rule1
 --tracef=./test_data/trace1

The result shows that the packet matches the second rule,  which is wrong.
The dest port of the pkt is 53, so it should match the third rule."

Indeed there is problem at ACL build stage.
Sometimes acl_merge_trie() is too aggressive in trying to conserve
space at build time.
So it takes a wrong assumptions and didn't duplicate a node,
even when it should.
The easiest and safest fix seems to always duplicate a left non-root/non-leaf
node first, and let the further code to destroy the node, if it is not needed.

Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
---
 lib/librte_acl/acl_bld.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/lib/librte_acl/acl_bld.c b/lib/librte_acl/acl_bld.c
index a406737..92a85df 100644
--- a/lib/librte_acl/acl_bld.c
+++ b/lib/librte_acl/acl_bld.c
@@ -1044,9 +1044,7 @@ acl_merge_trie(struct acl_build_context *context,
 	 * a subtree of the merging tree (node B side). Otherwise,
 	 * just use node A.
 	 */
-	if (level > 0 &&
-			node_a->subtree_id !=
-			(subtree_id | RTE_ACL_SUBTREE_NODE)) {
+	if (level > 0) {
 		node_c = acl_dup_node(context, node_a);
 		node_c->subtree_id = subtree_id | RTE_ACL_SUBTREE_NODE;
 	}
-- 
2.4.2