6 files changed, 62 insertions, 6 deletions

diff --git a/net/core/lwtunnel.c b/net/core/lwtunnel.c
index 669ecc9f884e..e5f84c26ba1a 100644
--- a/net/core/lwtunnel.c
+++ b/net/core/lwtunnel.c
@@ -251,6 +251,41 @@ drop:
 }
 EXPORT_SYMBOL(lwtunnel_output);
 
+int lwtunnel_xmit(struct sk_buff *skb)
+{
+	struct dst_entry *dst = skb_dst(skb);
+	const struct lwtunnel_encap_ops *ops;
+	struct lwtunnel_state *lwtstate;
+	int ret = -EINVAL;
+
+	if (!dst)
+		goto drop;
+
+	lwtstate = dst->lwtstate;
+
+	if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
+	    lwtstate->type > LWTUNNEL_ENCAP_MAX)
+		return 0;
+
+	ret = -EOPNOTSUPP;
+	rcu_read_lock();
+	ops = rcu_dereference(lwtun_encaps[lwtstate->type]);
+	if (likely(ops && ops->xmit))
+		ret = ops->xmit(skb);
+	rcu_read_unlock();
+
+	if (ret == -EOPNOTSUPP)
+		goto drop;
+
+	return ret;
+
+drop:
+	kfree_skb(skb);
+
+	return ret;
+}
+EXPORT_SYMBOL(lwtunnel_xmit);
+
 int lwtunnel_input(struct sk_buff *skb)
 {
 	struct dst_entry *dst = skb_dst(skb);
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index dde37fb340bf..65569274efb8 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -73,6 +73,7 @@
 #include <net/icmp.h>
 #include <net/checksum.h>
 #include <net/inetpeer.h>
+#include <net/lwtunnel.h>
 #include <linux/igmp.h>
 #include <linux/netfilter_ipv4.h>
 #include <linux/netfilter_bridge.h>
@@ -197,6 +198,13 @@ static int ip_finish_output2(struct net *net, struct sock *sk, struct sk_buff *s
 		skb = skb2;
 	}
 
+	if (lwtunnel_xmit_redirect(dst->lwtstate)) {
+		int res = lwtunnel_xmit(skb);
+
+		if (res < 0 || res == LWTUNNEL_XMIT_DONE)
+			return res;
+	}
+
 	rcu_read_lock_bh();
 	nexthop = (__force u32) rt_nexthop(rt, ip_hdr(skb)->daddr);
 	neigh = __ipv4_neigh_lookup_noref(dev, nexthop);
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index a1f2830d8110..3e992783c1d0 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1246,7 +1246,9 @@ static unsigned int ipv4_mtu(const struct dst_entry *dst)
 			mtu = 576;
 	}
 
-	return min_t(unsigned int, mtu, IP_MAX_MTU);
+	mtu = min_t(unsigned int, mtu, IP_MAX_MTU);
+
+	return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
 }
 
 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 1dfc402d9ad1..993fd9666f1b 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -56,6 +56,7 @@
 #include <net/checksum.h>
 #include <linux/mroute6.h>
 #include <net/l3mdev.h>
+#include <net/lwtunnel.h>
 
 static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
@@ -104,6 +105,13 @@ static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *
 		}
 	}
 
+	if (lwtunnel_xmit_redirect(dst->lwtstate)) {
+		int res = lwtunnel_xmit(skb);
+
+		if (res < 0 || res == LWTUNNEL_XMIT_DONE)
+			return res;
+	}
+
 	rcu_read_lock_bh();
 	nexthop = rt6_nexthop((struct rt6_info *)dst, &ipv6_hdr(skb)->daddr);
 	neigh = __ipv6_neigh_lookup_noref(dst->dev, nexthop);
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 49817555449e..09d43ff11a8d 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1604,7 +1604,9 @@ static unsigned int ip6_mtu(const struct dst_entry *dst)
 	rcu_read_unlock();
 
 out:
-	return min_t(unsigned int, mtu, IP6_MAX_MTU);
+	mtu = min_t(unsigned int, mtu, IP6_MAX_MTU);
+
+	return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
 }
 
 static struct dst_entry *icmp6_dst_gc_list;
diff --git a/net/mpls/mpls_iptunnel.c b/net/mpls/mpls_iptunnel.c
index 644a8da6d4bd..aed872cc05a6 100644
--- a/net/mpls/mpls_iptunnel.c
+++ b/net/mpls/mpls_iptunnel.c
@@ -37,7 +37,7 @@ static unsigned int mpls_encap_size(struct mpls_iptunnel_encap *en)
 	return en->labels * sizeof(struct mpls_shim_hdr);
 }
 
-static int mpls_output(struct net *net, struct sock *sk, struct sk_buff *skb)
+static int mpls_xmit(struct sk_buff *skb)
 {
 	struct mpls_iptunnel_encap *tun_encap_info;
 	struct mpls_shim_hdr *hdr;
@@ -115,7 +115,7 @@ static int mpls_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 		net_dbg_ratelimited("%s: packet transmission failed: %d\n",
 				    __func__, err);
 
-	return 0;
+	return LWTUNNEL_XMIT_DONE;
 
 drop:
 	kfree_skb(skb);
@@ -153,7 +153,8 @@ static int mpls_build_state(struct net_device *dev, struct nlattr *nla,
 	if (ret)
 		goto errout;
 	newts->type = LWTUNNEL_ENCAP_MPLS;
-	newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT;
+	newts->flags |= LWTUNNEL_STATE_XMIT_REDIRECT;
+	newts->headroom = mpls_encap_size(tun_encap_info);
 
 	*ts = newts;
 
@@ -209,7 +210,7 @@ static int mpls_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
 
 static const struct lwtunnel_encap_ops mpls_iptun_ops = {
 	.build_state = mpls_build_state,
-	.output = mpls_output,
+	.xmit = mpls_xmit,
 	.fill_encap = mpls_fill_encap_info,
 	.get_encap_size = mpls_encap_nlsize,
 	.cmp_encap = mpls_encap_cmp,