[PATCH 09/25] netns ct: get proper netns from netdevice

[PATCH 09/25] netns ct: get proper netns from netdevice

[Alexey Dobriyan]

Get netns from skb->dev on input, from skb->dst->dev on output to know
where to create or search for conntrack.

Is there some documentation re which device accessible from skb is valid
at which point?

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---

 net/netfilter/nf_conntrack_core.c |   12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -29,7 +29,7 @@
 #include <linux/netdevice.h>
 #include <linux/socket.h>
 #include <linux/mm.h>
-
+#include <net/dst.h>
 #include <net/netfilter/nf_conntrack.h>
 #include <net/netfilter/nf_conntrack_l3proto.h>
 #include <net/netfilter/nf_conntrack_l4proto.h>
@@ -615,6 +615,8 @@ resolve_normal_ct(struct sk_buff *skb,
 		  int *set_reply,
 		  enum ip_conntrack_info *ctinfo)
 {
+	struct net_device *dev;
+	struct net *net;
 	struct nf_conntrack_tuple tuple;
 	struct nf_conntrack_tuple_hash *h;
 	struct nf_conn *ct;
@@ -626,10 +628,14 @@ resolve_normal_ct(struct sk_buff *skb,
 		return NULL;
 	}
 
+	dev = skb->dev;
+	if (!dev)
+		dev = skb->dst->dev;
+	net = dev_net(dev);
 	/* look for tuple match */
-	h = nf_conntrack_find_get(&init_net, &tuple);
+	h = nf_conntrack_find_get(net, &tuple);
 	if (!h) {
-		h = init_conntrack(&init_net, &tuple, l3proto, l4proto, skb, dataoff);
+		h = init_conntrack(net, &tuple, l3proto, l4proto, skb, dataoff);
 		if (!h)
 			return NULL;
 		if (IS_ERR(h))
-- 
1.5.4.5

Re: [PATCH 09/25] netns ct: get proper netns from netdevice

[Patrick McHardy]

Alexey Dobriyan wrote:
> Get netns from skb->dev on input, from skb->dst->dev on output to know
> where to create or search for conntrack.
> 
> Is there some documentation re which device accessible from skb is valid
> at which point?

For netfilter hooks, skb->dev points to the input device in
PREROUTING, INPUT, FORWARD, to the output device in POSTROUTING
and is invalid in OUTPUT.

> @@ -626,10 +628,14 @@ resolve_normal_ct(struct sk_buff *skb,
>  		return NULL;
>  	}
>  
> +	dev = skb->dev;
> +	if (!dev)
> +		dev = skb->dst->dev;
> +	net = dev_net(dev);

Maybe just pass it though nf_conntrack_in from the hook functions,
those get the devices as arguments.