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" <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

drivers/net/vrf.c

@@ -298,14 +298,15 @@ static int vrf_finish_output(struct sock *sk, struct sk_buff *skb)
 static int vrf_output(struct sock *sk, struct sk_buff *skb)
 {
 	struct net_device *dev = skb_dst(skb)->dev;
+	struct net *net = dev_net(dev);
 
-	IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUT, skb->len);
+	IP_UPD_PO_STATS(net, IPSTATS_MIB_OUT, skb->len);
 
 	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,
 			    vrf_finish_output,
 			    !(IPCB(skb)->flags & IPSKB_REROUTED));
 }

include/linux/netfilter.h

@@ -190,12 +190,11 @@ static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
 	return 1;
 }
 
-static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sock *sk,
-			  struct sk_buff *skb, struct net_device *indev,
-			  struct net_device *outdev,
+static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
+			  struct sock *sk, struct sk_buff *skb,
+			  struct net_device *indev, struct net_device *outdev,
 			  int (*okfn)(struct sock *, struct sk_buff *))
 {
-	struct net *net = dev_net(indev ? indev : outdev);
 	return nf_hook_thresh(pf, hook, net, sk, skb, indev, outdev, okfn, INT_MIN);
 }
 
@@ -217,24 +216,22 @@ static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sock *sk,
 */
 
 static inline int
-NF_HOOK_THRESH(uint8_t pf, unsigned int hook, struct sock *sk,
+NF_HOOK_THRESH(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 	       struct sk_buff *skb, struct net_device *in,
 	       struct net_device *out,
 	       int (*okfn)(struct sock *, struct sk_buff *), int thresh)
 {
-	struct net *net = dev_net(in ? in : out);
 	int ret = nf_hook_thresh(pf, hook, net, sk, skb, in, out, okfn, thresh);
 	if (ret == 1)
 		ret = okfn(sk, skb);
 	return ret;
 }
 
 static inline int
-NF_HOOK_COND(uint8_t pf, unsigned int hook, struct sock *sk,
+NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
 	     struct sk_buff *skb, struct net_device *in, struct net_device *out,
 	     int (*okfn)(struct sock *, struct sk_buff *), bool cond)
 {
-	struct net *net = dev_net(in ? in : out);
 	int ret;
 
 	if (!cond ||
@@ -244,11 +241,11 @@ NF_HOOK_COND(uint8_t pf, unsigned int hook, struct sock *sk,
 }
 
 static inline int
-NF_HOOK(uint8_t pf, unsigned int hook, struct sock *sk, struct sk_buff *skb,
+NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, struct sk_buff *skb,
 	struct net_device *in, struct net_device *out,
 	int (*okfn)(struct sock *, struct sk_buff *))
 {
-	return NF_HOOK_THRESH(pf, hook, sk, skb, in, out, okfn, INT_MIN);
+	return NF_HOOK_THRESH(pf, hook, net, sk, skb, in, out, okfn, INT_MIN);
 }
 
 /* Call setsockopt() */
@@ -348,11 +345,11 @@ nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
 }
 
 #else /* !CONFIG_NETFILTER */
-#define NF_HOOK(pf, hook, sk, skb, indev, outdev, okfn) (okfn)(sk, skb)
-#define NF_HOOK_COND(pf, hook, sk, skb, indev, outdev, okfn, cond) (okfn)(sk, skb)
-static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sock *sk,
-			  struct sk_buff *skb, struct net_device *indev,
-			  struct net_device *outdev,
+#define NF_HOOK(pf, hook, net, sk, skb, indev, outdev, okfn) (okfn)(sk, skb)
+#define NF_HOOK_COND(pf, hook, net, sk, skb, indev, outdev, okfn, cond) (okfn)(sk, skb)
+static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
+			  struct sock *sk, struct sk_buff *skb,
+			  struct net_device *indev, struct net_device *outdev,
 			  int (*okfn)(struct sock *, struct sk_buff *))
 {
 	return 1;

net/bridge/br_forward.c

@@ -67,8 +67,9 @@ EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);
 
 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);
+	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING,
+		       net, sk, skb, NULL, skb->dev,
 		       br_dev_queue_push_xmit);
 
 }
@@ -92,8 +93,8 @@ static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
 		return;
 	}
 
-	NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, NULL, skb,
-		NULL, skb->dev,
+	NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT,
+		dev_net(skb->dev), NULL, skb,NULL, skb->dev,
 		br_forward_finish);
 }
 
@@ -114,8 +115,8 @@ static void __br_forward(const struct net_bridge_port *to, struct sk_buff *skb)
 	skb->dev = to->dev;
 	skb_forward_csum(skb);
 
-	NF_HOOK(NFPROTO_BRIDGE, NF_BR_FORWARD, NULL, skb,
-		indev, skb->dev,
+	NF_HOOK(NFPROTO_BRIDGE, NF_BR_FORWARD,
+		dev_net(indev), NULL, skb, indev, skb->dev,
 		br_forward_finish);
 }
 

net/bridge/br_input.c

@@ -60,8 +60,8 @@ static int br_pass_frame_up(struct sk_buff *skb)
 	if (!skb)
 		return NET_RX_DROP;
 
-	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, NULL, skb,
-		       indev, NULL,
+	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN,
+		       dev_net(indev), NULL, skb, indev, NULL,
 		       br_netif_receive_skb);
 }
 
@@ -283,8 +283,9 @@ rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
 		}
 
 		/* Deliver packet to local host only */
-		if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, NULL, skb,
-			    skb->dev, NULL, br_handle_local_finish)) {
+		if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN,
+			    dev_net(skb->dev), NULL, skb, skb->dev, NULL,
+			    br_handle_local_finish)) {
 			return RX_HANDLER_CONSUMED; /* consumed by filter */
 		} else {
 			*pskb = skb;
@@ -308,8 +309,8 @@ rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
 		if (ether_addr_equal(p->br->dev->dev_addr, dest))
 			skb->pkt_type = PACKET_HOST;
 
-		NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, NULL, skb,
-			skb->dev, NULL,
+		NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING,
+			dev_net(skb->dev), NULL, skb, skb->dev, NULL,
 			br_handle_frame_finish);
 		break;
 	default:

net/bridge/br_multicast.c

@@ -829,8 +829,8 @@ static void __br_multicast_send_query(struct net_bridge *br,
 
 	if (port) {
 		skb->dev = port->dev;
-		NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, NULL, skb,
-			NULL, skb->dev,
+		NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT,
+			dev_net(port->dev), NULL, skb, NULL, skb->dev,
 			br_dev_queue_push_xmit);
 	} else {
 		br_multicast_select_own_querier(br, ip, skb);

net/bridge/br_netfilter_hooks.c

@@ -394,7 +394,7 @@ static int br_nf_pre_routing_finish(struct sock *sk, struct sk_buff *skb)
 				nf_bridge_push_encap_header(skb);
 				NF_HOOK_THRESH(NFPROTO_BRIDGE,
 					       NF_BR_PRE_ROUTING,
-					       sk, skb, skb->dev, NULL,
+					       net, sk, skb, skb->dev, NULL,
 					       br_nf_pre_routing_finish_bridge,
 					       1);
 				return 0;
@@ -414,7 +414,7 @@ static int br_nf_pre_routing_finish(struct sock *sk, struct sk_buff *skb)
 	skb->dev = nf_bridge->physindev;
 	nf_bridge_update_protocol(skb);
 	nf_bridge_push_encap_header(skb);
-	NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, sk, skb,
+	NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, net, sk, skb,
 		       skb->dev, NULL,
 		       br_handle_frame_finish, 1);
 
@@ -512,7 +512,7 @@ static unsigned int br_nf_pre_routing(const struct nf_hook_ops *ops,
 
 	skb->protocol = htons(ETH_P_IP);
 
-	NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, state->sk, skb,
+	NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, state->net, state->sk, skb,
 		skb->dev, NULL,
 		br_nf_pre_routing_finish);
 
@@ -539,6 +539,7 @@ static unsigned int br_nf_local_in(const struct nf_hook_ops *ops,
 static int br_nf_forward_finish(struct sock *sk, struct sk_buff *skb)
 {
 	struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
+	struct net *net = dev_net(skb->dev);
 	struct net_device *in;
 
 	if (!IS_ARP(skb) && !IS_VLAN_ARP(skb)) {
@@ -560,7 +561,7 @@ static int br_nf_forward_finish(struct sock *sk, struct sk_buff *skb)
 	}
 	nf_bridge_push_encap_header(skb);
 
-	NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_FORWARD, sk, skb,
+	NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_FORWARD, net, sk, skb,
 		       in, skb->dev, br_forward_finish, 1);
 	return 0;
 }
@@ -627,7 +628,7 @@ static unsigned int br_nf_forward_ip(const struct nf_hook_ops *ops,
 	else
 		skb->protocol = htons(ETH_P_IPV6);
 
-	NF_HOOK(pf, NF_INET_FORWARD, NULL, skb,
+	NF_HOOK(pf, NF_INET_FORWARD, state->net, NULL, skb,
 		brnf_get_logical_dev(skb, state->in),
 		parent,	br_nf_forward_finish);
 
@@ -662,7 +663,7 @@ static unsigned int br_nf_forward_arp(const struct nf_hook_ops *ops,
 		return NF_ACCEPT;
 	}
 	*d = state->in;
-	NF_HOOK(NFPROTO_ARP, NF_ARP_FORWARD, state->sk, skb,
+	NF_HOOK(NFPROTO_ARP, NF_ARP_FORWARD, state->net, state->sk, skb,
 		state->in, state->out, br_nf_forward_finish);
 
 	return NF_STOLEN;
@@ -842,7 +843,7 @@ static unsigned int br_nf_post_routing(const struct nf_hook_ops *ops,
 	else
 		skb->protocol = htons(ETH_P_IPV6);
 
-	NF_HOOK(pf, NF_INET_POST_ROUTING, state->sk, skb,
+	NF_HOOK(pf, NF_INET_POST_ROUTING, state->net, state->sk, skb,
 		NULL, realoutdev,
 		br_nf_dev_queue_xmit);
 

net/bridge/br_netfilter_ipv6.c

@@ -166,6 +166,7 @@ static int br_nf_pre_routing_finish_ipv6(struct sock *sk, struct sk_buff *skb)
 	struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 	struct rtable *rt;
 	struct net_device *dev = skb->dev;
+	struct net *net = dev_net(dev);
 	const struct nf_ipv6_ops *v6ops = nf_get_ipv6_ops();
 
 	nf_bridge->frag_max_size = IP6CB(skb)->frag_max_size;
@@ -189,7 +190,7 @@ static int br_nf_pre_routing_finish_ipv6(struct sock *sk, struct sk_buff *skb)
 			nf_bridge_update_protocol(skb);
 			nf_bridge_push_encap_header(skb);
 			NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING,
-				       sk, skb, skb->dev, NULL,
+				       net, sk, skb, skb->dev, NULL,
 				       br_nf_pre_routing_finish_bridge,
 				       1);
 			return 0;
@@ -208,7 +209,7 @@ static int br_nf_pre_routing_finish_ipv6(struct sock *sk, struct sk_buff *skb)
 	skb->dev = nf_bridge->physindev;
 	nf_bridge_update_protocol(skb);
 	nf_bridge_push_encap_header(skb);
-	NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, sk, skb,
+	NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, net, sk, skb,
 		       skb->dev, NULL,
 		       br_handle_frame_finish, 1);
 
@@ -237,7 +238,7 @@ unsigned int br_nf_pre_routing_ipv6(const struct nf_hook_ops *ops,
 	nf_bridge->ipv6_daddr = ipv6_hdr(skb)->daddr;
 
 	skb->protocol = htons(ETH_P_IPV6);
-	NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, state->sk, skb,
+	NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, state->net, state->sk, skb,
 		skb->dev, NULL,
 		br_nf_pre_routing_finish_ipv6);
 

net/bridge/br_stp_bpdu.c

@@ -59,8 +59,8 @@ static void br_send_bpdu(struct net_bridge_port *p,
 
 	skb_reset_mac_header(skb);
 
-	NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, NULL, skb,
-		NULL, skb->dev,
+	NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT,
+		dev_net(p->dev), NULL, skb, NULL, skb->dev,
 		br_send_bpdu_finish);
 }
 

net/decnet/dn_neigh.c

@@ -246,8 +246,9 @@ static int dn_long_output(struct neighbour *neigh, struct sock *sk,
 
 	skb_reset_network_header(skb);
 
-	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, sk, skb,
-		       NULL, neigh->dev, dn_neigh_output_packet);
+	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING,
+		       &init_net, sk, skb, NULL, neigh->dev,
+		       dn_neigh_output_packet);
 }
 
 /*
@@ -286,8 +287,9 @@ static int dn_short_output(struct neighbour *neigh, struct sock *sk,
 
 	skb_reset_network_header(skb);
 
-	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, sk, skb,
-		       NULL, neigh->dev, dn_neigh_output_packet);
+	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING,
+		       &init_net, sk, skb, NULL, neigh->dev,
+		       dn_neigh_output_packet);
 }
 
 /*
@@ -327,8 +329,9 @@ static int dn_phase3_output(struct neighbour *neigh, struct sock *sk,
 
 	skb_reset_network_header(skb);
 
-	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, sk, skb,
-		       NULL, neigh->dev, dn_neigh_output_packet);
+	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING,
+		       &init_net, sk, skb, NULL, neigh->dev,
+		       dn_neigh_output_packet);
 }
 
 int dn_to_neigh_output(struct sock *sk, struct sk_buff *skb)

net/decnet/dn_nsp_in.c

@@ -814,8 +814,8 @@ static int dn_nsp_rx_packet(struct sock *sk2, struct sk_buff *skb)
 
 int dn_nsp_rx(struct sk_buff *skb)
 {
-	return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_IN, NULL, skb,
-		       skb->dev, NULL,
+	return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_IN,
+		       &init_net, NULL, skb, skb->dev, NULL,
 		       dn_nsp_rx_packet);
 }