Merge branch 'xfrm: policy: replace session decode with flow dissector'

Florian Westphal says:

============
Remove the ipv4+ipv6 session decode functions and use generic flow
dissector to populate the flowi for the policy lookup.

Changes since v2:
- first patch broke CONFIG_XFRM=n builds

Changes since v1:
- Can't use skb_flow_dissect(), we might see skbs that have neither
  skb->sk nor skb->dev set. Flow dissector WARN()s in this case, it
  tries to check for a bpf program assigned in that net namespace.

Add a preparation patch to pass down 'struct net' in
xfrm_decode_session so its available for use in patch 3.

Changes since RFC:

- Drop mobility header support.  I don't think that anyone uses
  this.  MOBIKE doesn't appear to need this either.
- Drop fl6->flowlabel assignment, original code leaves it as 0.

There is no reason for this change other than to remove code.
============
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

include/net/xfrm.h

@@ -1207,20 +1207,20 @@ static inline int xfrm6_policy_check_reverse(struct sock *sk, int dir,
 	return __xfrm_policy_check2(sk, dir, skb, AF_INET6, 1);
 }
 
-int __xfrm_decode_session(struct sk_buff *skb, struct flowi *fl,
+int __xfrm_decode_session(struct net *net, struct sk_buff *skb, struct flowi *fl,
 			  unsigned int family, int reverse);
 
-static inline int xfrm_decode_session(struct sk_buff *skb, struct flowi *fl,
+static inline int xfrm_decode_session(struct net *net, struct sk_buff *skb, struct flowi *fl,
 				      unsigned int family)
 {
-	return __xfrm_decode_session(skb, fl, family, 0);
+	return __xfrm_decode_session(net, skb, fl, family, 0);
 }
 
-static inline int xfrm_decode_session_reverse(struct sk_buff *skb,
+static inline int xfrm_decode_session_reverse(struct net *net, struct sk_buff *skb,
 					      struct flowi *fl,
 					      unsigned int family)
 {
-	return __xfrm_decode_session(skb, fl, family, 1);
+	return __xfrm_decode_session(net, skb, fl, family, 1);
 }
 
 int __xfrm_route_forward(struct sk_buff *skb, unsigned short family);
@@ -1296,7 +1296,7 @@ static inline int xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *sk
 {
 	return 1;
 }
-static inline int xfrm_decode_session_reverse(struct sk_buff *skb,
+static inline int xfrm_decode_session_reverse(struct net *net, struct sk_buff *skb,
 					      struct flowi *fl,
 					      unsigned int family)
 {

net/ipv4/icmp.c

@@ -517,7 +517,7 @@ static struct rtable *icmp_route_lookup(struct net *net,
 	} else
 		return rt;
 
-	err = xfrm_decode_session_reverse(skb_in, flowi4_to_flowi(&fl4_dec), AF_INET);
+	err = xfrm_decode_session_reverse(net, skb_in, flowi4_to_flowi(&fl4_dec), AF_INET);
 	if (err)
 		goto relookup_failed;
 

net/ipv4/ip_vti.c

@@ -288,11 +288,11 @@ static netdev_tx_t vti_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 	switch (skb->protocol) {
 	case htons(ETH_P_IP):
 		memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
-		xfrm_decode_session(skb, &fl, AF_INET);
+		xfrm_decode_session(dev_net(dev), skb, &fl, AF_INET);
 		break;
 	case htons(ETH_P_IPV6):
 		memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
-		xfrm_decode_session(skb, &fl, AF_INET6);
+		xfrm_decode_session(dev_net(dev), skb, &fl, AF_INET6);
 		break;
 	default:
 		goto tx_err;

net/ipv4/netfilter.c

@@ -62,7 +62,7 @@ int ip_route_me_harder(struct net *net, struct sock *sk, struct sk_buff *skb, un
 
 #ifdef CONFIG_XFRM
 	if (!(IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) &&
-	    xfrm_decode_session(skb, flowi4_to_flowi(&fl4), AF_INET) == 0) {
+	    xfrm_decode_session(net, skb, flowi4_to_flowi(&fl4), AF_INET) == 0) {
 		struct dst_entry *dst = skb_dst(skb);
 		skb_dst_set(skb, NULL);
 		dst = xfrm_lookup(net, dst, flowi4_to_flowi(&fl4), sk, 0);

net/ipv6/icmp.c

@@ -385,7 +385,7 @@ static struct dst_entry *icmpv6_route_lookup(struct net *net,
 			return dst;
 	}
 
-	err = xfrm_decode_session_reverse(skb, flowi6_to_flowi(&fl2), AF_INET6);
+	err = xfrm_decode_session_reverse(net, skb, flowi6_to_flowi(&fl2), AF_INET6);
 	if (err)
 		goto relookup_failed;
 

net/ipv6/ip6_vti.c

@@ -569,11 +569,11 @@ vti6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
 			goto tx_err;
 
 		memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
-		xfrm_decode_session(skb, &fl, AF_INET6);
+		xfrm_decode_session(dev_net(dev), skb, &fl, AF_INET6);
 		break;
 	case htons(ETH_P_IP):
 		memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
-		xfrm_decode_session(skb, &fl, AF_INET);
+		xfrm_decode_session(dev_net(dev), skb, &fl, AF_INET);
 		break;
 	default:
 		goto tx_err;

net/ipv6/netfilter.c

@@ -61,7 +61,7 @@ int ip6_route_me_harder(struct net *net, struct sock *sk_partial, struct sk_buff
 
 #ifdef CONFIG_XFRM
 	if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
-	    xfrm_decode_session(skb, flowi6_to_flowi(&fl6), AF_INET6) == 0) {
+	    xfrm_decode_session(net, skb, flowi6_to_flowi(&fl6), AF_INET6) == 0) {
 		skb_dst_set(skb, NULL);
 		dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0);
 		if (IS_ERR(dst))

net/netfilter/nf_nat_proto.c

@@ -668,7 +668,7 @@ static int nf_xfrm_me_harder(struct net *net, struct sk_buff *skb, unsigned int
 	struct flowi fl;
 	int err;
 
-	err = xfrm_decode_session(skb, &fl, family);
+	err = xfrm_decode_session(net, skb, &fl, family);
 	if (err < 0)
 		return err;
 

net/xfrm/xfrm_interface_core.c

@@ -538,7 +538,7 @@ static netdev_tx_t xfrmi_xmit(struct sk_buff *skb, struct net_device *dev)
 	switch (skb->protocol) {
 	case htons(ETH_P_IPV6):
 		memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
-		xfrm_decode_session(skb, &fl, AF_INET6);
+		xfrm_decode_session(dev_net(dev), skb, &fl, AF_INET6);
 		if (!dst) {
 			fl.u.ip6.flowi6_oif = dev->ifindex;
 			fl.u.ip6.flowi6_flags |= FLOWI_FLAG_ANYSRC;
@@ -553,7 +553,7 @@ static netdev_tx_t xfrmi_xmit(struct sk_buff *skb, struct net_device *dev)
 		break;
 	case htons(ETH_P_IP):
 		memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
-		xfrm_decode_session(skb, &fl, AF_INET);
+		xfrm_decode_session(dev_net(dev), skb, &fl, AF_INET);
 		if (!dst) {
 			struct rtable *rt;