net: openvswitch: add log message for error case

As requested by upstream OVS, added some error messages in the
validate_and_copy_dec_ttl function.

Includes a small cleanup, which removes an unnecessary parameter
from the dec_ttl_exception_handler() function.

Reported-by: Flavio Leitner <[e-mail]>
Signed-off-by: Eelco Chaudron <[e-mail]>
Acked-by: Flavio Leitner <[e-mail]>
Link: https://lore.kernel.org/r/161054576573.26637.18396634650212670580.stgit@ebuild
Signed-off-by: Jakub Kicinski <[e-mail]>

net/openvswitch/actions.c

···
 
 static int dec_ttl_exception_handler(struct datapath *dp, struct sk_buff *skb,
 				     struct sw_flow_key *key,
-				     const struct nlattr *attr, bool last)
+				     const struct nlattr *attr)
 {
 	/* The first attribute is always 'OVS_DEC_TTL_ATTR_ACTION'. */
 	struct nlattr *actions = nla_data(attr);
 
 	if (nla_len(actions))
 		return clone_execute(dp, skb, key, 0, nla_data(actions),
-				     nla_len(actions), last, false);
+				     nla_len(actions), true, false);
 
 	consume_skb(skb);
 	return 0;
···
 
 		case OVS_ACTION_ATTR_DEC_TTL:
 			err = execute_dec_ttl(skb, key);
-			if (err == -EHOSTUNREACH) {
-				err = dec_ttl_exception_handler(dp, skb, key,
-								a, true);
-				return err;
-			}
+			if (err == -EHOSTUNREACH)
+				return dec_ttl_exception_handler(dp, skb,
+								 key, a);
 			break;
 		}
 

net/openvswitch/flow_netlink.c

···
 		if (type > OVS_DEC_TTL_ATTR_MAX)
 			continue;
 
-		if (!type || attrs[type])
+		if (!type || attrs[type]) {
+			OVS_NLERR(log, "Duplicate or invalid key (type %d).",
+				  type);
 			return -EINVAL;
+		}
 
 		attrs[type] = a;
 	}
 
-	actions = attrs[OVS_DEC_TTL_ATTR_ACTION];
-	if (rem || !actions || (nla_len(actions) && nla_len(actions) < NLA_HDRLEN))
+	if (rem) {
+		OVS_NLERR(log, "Message has %d unknown bytes.", rem);
 		return -EINVAL;
+	}
+
+	actions = attrs[OVS_DEC_TTL_ATTR_ACTION];
+	if (!actions || (nla_len(actions) && nla_len(actions) < NLA_HDRLEN)) {
+		OVS_NLERR(log, "Missing valid actions attribute.");
+		return -EINVAL;
+	}
 
 	start = add_nested_action_start(sfa, OVS_ACTION_ATTR_DEC_TTL, log);
 	if (start < 0)