netfilter: Pass struct net into the netfilter hooks
Pass a network namespace parameter into the netfilter hooks. At the
call site of the netfilter hooks the path a packet is taking through
the network stack is well known which allows the network namespace to
be easily and reliabily.
This allows the replacement of magic code like
"dev_net(state->in?:state->out)" that appears at the start of most
netfilter hooks with "state->net".
In almost all cases the network namespace passed in is derived
from the first network device passed in, guaranteeing those
paths will not see any changes in practice.
The exceptions are:
xfrm/xfrm_output.c:xfrm_output_resume() xs_net(skb_dst(skb)->xfrm)
ipvs/ip_vs_xmit.c:ip_vs_nat_send_or_cont() ip_vs_conn_net(cp)
ipvs/ip_vs_xmit.c:ip_vs_send_or_cont() ip_vs_conn_net(cp)
ipv4/raw.c:raw_send_hdrinc() sock_net(sk)
ipv6/ip6_output.c:ip6_xmit() sock_net(sk)
ipv6/ndisc.c:ndisc_send_skb() dev_net(skb->dev) not dev_net(dst->dev)
ipv6/raw.c:raw6_send_hdrinc() sock_net(sk)
br_netfilter_hooks.c:br_nf_pre_routing_finish() dev_net(skb->dev) before skb->dev is set to nf_bridge->physindev
In all cases these exceptions seem to be a better expression for the
network namespace the packet is being processed in then the historic
"dev_net(in?in:out)". I am documenting them in case something odd
pops up and someone starts trying to track down what happened.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/xfrm4_output.c b/net/ipv4/xfrm4_output.c
index 737f5e3..e4a8519 100644
--- a/net/ipv4/xfrm4_output.c
+++ b/net/ipv4/xfrm4_output.c
@@ -96,8 +96,10 @@
int xfrm4_output(struct sock *sk, struct sk_buff *skb)
{
- return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, sk, skb,
- NULL, skb_dst(skb)->dev, __xfrm4_output,
+ struct net *net = dev_net(skb_dst(skb)->dev);
+ return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
+ net, sk, skb, NULL, skb_dst(skb)->dev,
+ __xfrm4_output,
!(IPCB(skb)->flags & IPSKB_REROUTED));
}
