[PATCH net v2] net: openvswitch: fix TTL decrement exception action execution

[Eelco Chaudron <echaudro@redhat.com>]

Currently, the exception actions are not processed correctly as the wrong
dataset is passed. This change fixes this, including the misleading
comment.

In addition, a check was added to make sure we work on an IPv4 packet,
and not just assume if it's not IPv6 it's IPv4.

This was all tested using OVS with patch,
https://patchwork.ozlabs.org/project/openvswitch/list/?series=21639,
applied and sending packets with a TTL of 1 (and 0), both with IPv4
and IPv6.

Fixes: 69929d4c49e1 ("net: openvswitch: fix TTL decrement action netlink message format")
Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
---
v2: - Undid unnessesary paramerter removal from dec_ttl_exception_handler()
    - Updated commit message to include testing information.

 net/openvswitch/actions.c |   15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index 5829a020b81c..ace69777cb29 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -956,16 +956,13 @@ static int dec_ttl_exception_handler(struct datapath *dp, struct sk_buff *skb,
 				     struct sw_flow_key *key,
 				     const struct nlattr *attr, bool last)
 {
-	/* The first action is always 'OVS_DEC_TTL_ATTR_ARG'. */
-	struct nlattr *dec_ttl_arg = nla_data(attr);
+	/* The first attribute is always 'OVS_DEC_TTL_ATTR_ACTION'. */
+	struct nlattr *actions = nla_data(attr);
 
-	if (nla_len(dec_ttl_arg)) {
-		struct nlattr *actions = nla_data(dec_ttl_arg);
+	if (nla_len(actions))
+		return clone_execute(dp, skb, key, 0, nla_data(actions),
+				     nla_len(actions), last, false);
 
-		if (actions)
-			return clone_execute(dp, skb, key, 0, nla_data(actions),
-					     nla_len(actions), last, false);
-	}
 	consume_skb(skb);
 	return 0;
 }
@@ -1209,7 +1206,7 @@ static int execute_dec_ttl(struct sk_buff *skb, struct sw_flow_key *key)
 			return -EHOSTUNREACH;
 
 		key->ip.ttl = --nh->hop_limit;
-	} else {
+	} else if (skb->protocol == htons(ETH_P_IP)) {
 		struct iphdr *nh;
 		u8 old_ttl;