Le 16/09/2015 03:04, Eric W. Biederman a écrit :
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" <ebied...@xmission.com>
---
[snip]
  int br_forward_finish(struct sock *sk, struct sk_buff *skb)
  {
-       return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING, sk, skb,
-                      NULL, skb->dev,
+       struct net *net = dev_net(skb->dev);
nit: blank line after the declaration

+       return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING,
+                      net, sk, skb, NULL, skb->dev,
                       br_dev_queue_push_xmit);

  }
[snip]
  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);
nit: same here

+       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));
  }
[snip]
  int xfrm6_output(struct sock *sk, struct sk_buff *skb)
  {
-       return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING, sk, skb,
-                           NULL, skb_dst(skb)->dev, __xfrm6_output,
+       struct net *net = dev_net(skb_dst(skb)->dev);
nit: same here

+       return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
+                           net, sk, skb,  NULL, skb_dst(skb)->dev,
+                           __xfrm6_output,
                            !(IP6CB(skb)->flags & IP6SKB_REROUTED));
  }
[snip]
  int xfrm_output_resume(struct sk_buff *skb, int err)
  {
+       struct net *net = xs_net(skb_dst(skb)->xfrm);
nit: same here

        while (likely((err = xfrm_output_one(skb, err)) == 0)) {
                nf_reset(skb);

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to