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/ip_output.c b/net/ipv4/ip_output.c
index fc550e97..4c95322 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -97,12 +97,14 @@
static int __ip_local_out_sk(struct sock *sk, struct sk_buff *skb)
{
+ struct net *net = dev_net(skb_dst(skb)->dev);
struct iphdr *iph = ip_hdr(skb);
iph->tot_len = htons(skb->len);
ip_send_check(iph);
- return nf_hook(NFPROTO_IPV4, NF_INET_LOCAL_OUT, sk, skb, NULL,
- skb_dst(skb)->dev, dst_output);
+ return nf_hook(NFPROTO_IPV4, NF_INET_LOCAL_OUT,
+ net, sk, skb, NULL, skb_dst(skb)->dev,
+ dst_output);
}
int __ip_local_out(struct sk_buff *skb)
@@ -322,7 +324,7 @@
struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
if (newskb)
NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING,
- sk, newskb, NULL, newskb->dev,
+ net, sk, newskb, NULL, newskb->dev,
dev_loopback_xmit);
}
@@ -337,12 +339,14 @@
if (rt->rt_flags&RTCF_BROADCAST) {
struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
if (newskb)
- NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, sk, newskb,
- NULL, newskb->dev, dev_loopback_xmit);
+ NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING,
+ net, sk, newskb, NULL, newskb->dev,
+ dev_loopback_xmit);
}
- return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, sk, skb, NULL,
- skb->dev, ip_finish_output,
+ return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
+ net, sk, skb, NULL, skb->dev,
+ ip_finish_output,
!(IPCB(skb)->flags & IPSKB_REROUTED));
}
@@ -356,8 +360,8 @@
skb->dev = dev;
skb->protocol = htons(ETH_P_IP);
- return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, sk, skb,
- NULL, dev,
+ return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
+ net, sk, skb, NULL, dev,
ip_finish_output,
!(IPCB(skb)->flags & IPSKB_REROUTED));
}