[ovs-dev] [PATCH] datapath: Kernel flow metadata parsing should be less restrictive

[Ansis Atteka]

The function flow_metadata_from_nlattrs() is very restrictive
about the ordering and type of metadata attributes that it receives.
This patch will change flow_metadata_from_nlattrs() behavior by
ignoring attributes that it does not understand and allowing them
to be passed in arbitrary order.

Issue #8167
---
 datapath/flow.c |   17 +++++------------
 1 files changed, 5 insertions(+), 12 deletions(-)

diff --git a/datapath/flow.c b/datapath/flow.c
index 2dc87ae..287816f 100644
--- a/datapath/flow.c
+++ b/datapath/flow.c
@@ -1166,43 +1166,36 @@ int flow_metadata_from_nlattrs(u32 *priority, u16 *in_port, __be64 *tun_id,
 			       const struct nlattr *attr)
 {
 	const struct nlattr *nla;
-	u16 prev_type;
 	int rem;
 
 	*in_port = USHRT_MAX;
 	*tun_id = 0;
 	*priority = 0;
 
-	prev_type = OVS_KEY_ATTR_UNSPEC;
 	nla_for_each_nested(nla, attr, rem) {
 		int type = nla_type(nla);
 
 		if (type > OVS_KEY_ATTR_MAX || nla_len(nla) != ovs_key_lens[type])
 			return -EINVAL;
 
-		switch (TRANSITION(prev_type, type)) {
-		case TRANSITION(OVS_KEY_ATTR_UNSPEC, OVS_KEY_ATTR_PRIORITY):
+		switch (type) {
+		case OVS_KEY_ATTR_PRIORITY:
 			*priority = nla_get_u32(nla);
 			break;
 
-		case TRANSITION(OVS_KEY_ATTR_UNSPEC, OVS_KEY_ATTR_TUN_ID):
-		case TRANSITION(OVS_KEY_ATTR_PRIORITY, OVS_KEY_ATTR_TUN_ID):
+		case OVS_KEY_ATTR_TUN_ID:
 			*tun_id = nla_get_be64(nla);
 			break;
 
-		case TRANSITION(OVS_KEY_ATTR_UNSPEC, OVS_KEY_ATTR_IN_PORT):
-		case TRANSITION(OVS_KEY_ATTR_PRIORITY, OVS_KEY_ATTR_IN_PORT):
-		case TRANSITION(OVS_KEY_ATTR_TUN_ID, OVS_KEY_ATTR_IN_PORT):
+		case OVS_KEY_ATTR_IN_PORT:
 			if (nla_get_u32(nla) >= DP_MAX_PORTS)
 				return -EINVAL;
 			*in_port = nla_get_u32(nla);
 			break;
 
 		default:
-			return 0;
+			break;
 		}
-
-		prev_type = type;
 	}
 	if (rem)
 		return -EINVAL;
-- 
1.7.4.1