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>

10 files changed, 32 insertions, 26 deletions

diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index c628dba477d4..583cf959c23d 100644
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -183,8 +183,8 @@ int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt
 	/* Must drop socket now because of tproxy. */
 	skb_orphan(skb);
 
-	return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, NULL, skb,
-		       dev, NULL,
+	return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
+		       net, NULL, skb, dev, NULL,
 		       ip6_rcv_finish);
 err:
 	IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS);
@@ -278,8 +278,8 @@ discard:
 
 int ip6_input(struct sk_buff *skb)
 {
-	return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN, NULL, skb,
-		       skb->dev, NULL,
+	return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN,
+		       dev_net(skb->dev), NULL, skb, skb->dev, NULL,
 		       ip6_input_finish);
 }
 
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 8cab909b181e..96e76ddd4a44 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -83,7 +83,7 @@ static int ip6_finish_output2(struct sock *sk, struct sk_buff *skb)
 			 */
 			if (newskb)
 				NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING,
-					sk, newskb, NULL, newskb->dev,
+					net, sk, newskb, NULL, newskb->dev,
 					dev_loopback_xmit);
 
 			if (ipv6_hdr(skb)->hop_limit == 0) {
@@ -142,8 +142,8 @@ int ip6_output(struct sock *sk, struct sk_buff *skb)
 		return 0;
 	}
 
-	return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING, sk, skb,
-			    NULL, dev,
+	return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
+			    net, sk, skb, NULL, dev,
 			    ip6_finish_output,
 			    !(IP6CB(skb)->flags & IP6SKB_REROUTED));
 }
@@ -223,8 +223,9 @@ int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
 	if ((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb)) {
 		IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)),
 			      IPSTATS_MIB_OUT, skb->len);
-		return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, sk, skb,
-			       NULL, dst->dev, dst_output);
+		return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
+			       net, sk, skb, NULL, dst->dev,
+			       dst_output);
 	}
 
 	skb->dev = dst->dev;
@@ -511,8 +512,8 @@ int ip6_forward(struct sk_buff *skb)
 
 	IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
 	IP6_ADD_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len);
-	return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD, NULL, skb,
-		       skb->dev, dst->dev,
+	return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD,
+		       net, NULL, skb, skb->dev, dst->dev,
 		       ip6_forward_finish);
 
 error:
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 3e3085b37a91..e830942b2090 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -2064,8 +2064,8 @@ static int ip6mr_forward2(struct net *net, struct mr6_table *mrt,
 
 	IP6CB(skb)->flags |= IP6SKB_FORWARDED;
 
-	return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD, NULL, skb,
-		       skb->dev, dev,
+	return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD,
+		       net, NULL, skb, skb->dev, dev,
 		       ip6mr_forward2_finish);
 
 out_free:
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index 5b3f2841acf6..124338a39e29 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -1645,7 +1645,7 @@ static void mld_sendpack(struct sk_buff *skb)
 	payload_len = skb->len;
 
 	err = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
-		      net->ipv6.igmp_sk, skb, NULL, skb->dev,
+		      net, net->ipv6.igmp_sk, skb, NULL, skb->dev,
 		      dst_output);
 out:
 	if (!err) {
@@ -2008,8 +2008,9 @@ static void igmp6_send(struct in6_addr *addr, struct net_device *dev, int type)
 	}
 
 	skb_dst_set(skb, dst);
-	err = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, sk, skb,
-		      NULL, skb->dev, dst_output);
+	err = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
+		      net, sk, skb, NULL, skb->dev,
+		      dst_output);
 out:
 	if (!err) {
 		ICMP6MSGOUT_INC_STATS(net, idev, type);
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 349ac1b022b6..dd2b08d7c8d1 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -463,8 +463,8 @@ static void ndisc_send_skb(struct sk_buff *skb,
 	idev = __in6_dev_get(dst->dev);
 	IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUT, skb->len);
 
-	err = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, sk, skb,
-		      NULL, dst->dev,
+	err = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
+		      net, sk, skb, NULL, dst->dev,
 		      dst_output);
 	if (!err) {
 		ICMP6MSGOUT_INC_STATS(net, idev, type);
diff --git a/net/ipv6/netfilter/nf_defrag_ipv6_hooks.c b/net/ipv6/netfilter/nf_defrag_ipv6_hooks.c
index 6d9c0b3d5b8c..6b576be3c83e 100644
--- a/net/ipv6/netfilter/nf_defrag_ipv6_hooks.c
+++ b/net/ipv6/netfilter/nf_defrag_ipv6_hooks.c
@@ -74,7 +74,7 @@ static unsigned int ipv6_defrag(const struct nf_hook_ops *ops,
 
 	nf_ct_frag6_consume_orig(reasm);
 
-	NF_HOOK_THRESH(NFPROTO_IPV6, ops->hooknum, state->sk, reasm,
+	NF_HOOK_THRESH(NFPROTO_IPV6, ops->hooknum, state->net, state->sk, reasm,
 		       state->in, state->out,
 		       state->okfn, NF_IP6_PRI_CONNTRACK_DEFRAG + 1);
 
diff --git a/net/ipv6/output_core.c b/net/ipv6/output_core.c
index 8178f72fe90d..9cc9127fb5e7 100644
--- a/net/ipv6/output_core.c
+++ b/net/ipv6/output_core.c
@@ -140,6 +140,7 @@ EXPORT_SYMBOL(ip6_dst_hoplimit);
 
 static int __ip6_local_out_sk(struct sock *sk, struct sk_buff *skb)
 {
+	struct net *net = dev_net(skb_dst(skb)->dev);
 	int len;
 
 	len = skb->len - sizeof(struct ipv6hdr);
@@ -148,8 +149,9 @@ static int __ip6_local_out_sk(struct sock *sk, struct sk_buff *skb)
 	ipv6_hdr(skb)->payload_len = htons(len);
 	IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
 
-	return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, sk, skb,
-		       NULL, skb_dst(skb)->dev, dst_output);
+	return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
+		       net, sk, skb, NULL, skb_dst(skb)->dev,
+		       dst_output);
 }
 
 int __ip6_local_out(struct sk_buff *skb)
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 5aa461302716..dc65ec198f7c 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -654,7 +654,7 @@ static int rawv6_send_hdrinc(struct sock *sk, struct msghdr *msg, int length,
 		goto error_fault;
 
 	IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len);
-	err = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, sk, skb,
+	err = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, net, sk, skb,
 		      NULL, rt->dst.dev, dst_output);
 	if (err > 0)
 		err = net_xmit_errno(err);
diff --git a/net/ipv6/xfrm6_input.c b/net/ipv6/xfrm6_input.c
index 74bd17882a2f..0eaab1fa6be5 100644
--- a/net/ipv6/xfrm6_input.c
+++ b/net/ipv6/xfrm6_input.c
@@ -42,8 +42,8 @@ int xfrm6_transport_finish(struct sk_buff *skb, int async)
 	ipv6_hdr(skb)->payload_len = htons(skb->len);
 	__skb_push(skb, skb->data - skb_network_header(skb));
 
-	NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, NULL, skb,
-		skb->dev, NULL,
+	NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
+		dev_net(skb->dev), NULL, skb, skb->dev, NULL,
 		ip6_rcv_finish);
 	return -1;
 }
diff --git a/net/ipv6/xfrm6_output.c b/net/ipv6/xfrm6_output.c
index b0fcd6c09837..431ae2c22234 100644
--- a/net/ipv6/xfrm6_output.c
+++ b/net/ipv6/xfrm6_output.c
@@ -168,7 +168,9 @@ static int __xfrm6_output(struct sock *sk, struct sk_buff *skb)
 
 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);
+	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));
 }