act_nat: get the position info from skb->tc_verd

act_nat uses its flags field to determine where it acts. It isn't reliable, and can't prevent users from doing wrong settings, and act_nat should get the position info from skb->tc_verd as act_mirred does.

----

 include/net/tc_act/tc_nat.h |    2 +-
 net/sched/act_nat.c         |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

index 4a691f3..343376a 100644
@@ -10,7 +10,7 @@ struct tcf_nat {
 	__be32 old_addr;
 	__be32 new_addr;
 	__be32 mask;
-	u32 flags;
+	u32 flags;	/* unused */
 };
 
 static inline struct tcf_nat *to_tcf_nat(struct tcf_common *pc)

index 24e614c..144e118 100644
@@ -121,7 +121,7 @@ static int tcf_nat(struct sk_buff *skb, struct tc_action *a,
 	old_addr = p->old_addr;
 	new_addr = p->new_addr;
 	mask = p->mask;
-	egress = p->flags & TCA_NAT_FLAG_EGRESS;
+	egress = G_TC_AT(skb->tc_verd) & AT_EGRESS;
 	action = p->tcf_action;
 
 	p->tcf_bstats.bytes += qdisc_pkt_len(skb);

Nack, the direction controls whether we NAT saddr or daddr. It's perfectly OK for someone to NAT daddr on the way out.

Cheers,

Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Thanks for your explanation. However, ingress and egress aren't as comprehensive as DNAT and SNAT. BTW I am planning to add stateless PAT(Port Address Translation) support into act_nat. Any comment?

Regards,
Changli Gao([email protected])