net: UDP tunnel encapsulation module for tunnelling different protocols like MPLS, IP, NSH etc.

The Bareudp tunnel module provides a generic L3 encapsulation
tunnelling module for tunnelling different protocols like MPLS,
IP,NSH etc inside a UDP tunnel.

Signed-off-by: Martin Varghese <martin.varghese@nokia.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 118 insertions, 0 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index ebe7060d0fc9..042599cc691d 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2774,6 +2774,54 @@ struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
 }
 EXPORT_SYMBOL_GPL(ip_route_output_flow);
 
+struct rtable *ip_route_output_tunnel(struct sk_buff *skb,
+				      struct net_device *dev,
+				      struct net *net, __be32 *saddr,
+				      const struct ip_tunnel_info *info,
+				      u8 protocol, bool use_cache)
+{
+#ifdef CONFIG_DST_CACHE
+	struct dst_cache *dst_cache;
+#endif
+	struct rtable *rt = NULL;
+	struct flowi4 fl4;
+	__u8 tos;
+
+#ifdef CONFIG_DST_CACHE
+	dst_cache = (struct dst_cache *)&info->dst_cache;
+	if (use_cache) {
+		rt = dst_cache_get_ip4(dst_cache, saddr);
+		if (rt)
+			return rt;
+	}
+#endif
+	memset(&fl4, 0, sizeof(fl4));
+	fl4.flowi4_mark = skb->mark;
+	fl4.flowi4_proto = protocol;
+	fl4.daddr = info->key.u.ipv4.dst;
+	fl4.saddr = info->key.u.ipv4.src;
+	tos = info->key.tos;
+	fl4.flowi4_tos = RT_TOS(tos);
+
+	rt = ip_route_output_key(net, &fl4);
+	if (IS_ERR(rt)) {
+		netdev_dbg(dev, "no route to %pI4\n", &fl4.daddr);
+		return ERR_PTR(-ENETUNREACH);
+	}
+	if (rt->dst.dev == dev) { /* is this necessary? */
+		netdev_dbg(dev, "circular route to %pI4\n", &fl4.daddr);
+		ip_rt_put(rt);
+		return ERR_PTR(-ELOOP);
+	}
+#ifdef CONFIG_DST_CACHE
+	if (use_cache)
+		dst_cache_set_ip4(dst_cache, &rt->dst, fl4.saddr);
+#endif
+	*saddr = fl4.saddr;
+	return rt;
+}
+EXPORT_SYMBOL_GPL(ip_route_output_tunnel);
+
 /* called with rcu_read_lock held */
 static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
 			struct rtable *rt, u32 table_id, struct flowi4 *fl4,
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 087304427bbb..8a8c2d0cfcc8 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -54,6 +54,7 @@
 #include <linux/mroute6.h>
 #include <net/l3mdev.h>
 #include <net/lwtunnel.h>
+#include <net/ip_tunnels.h>
 
 static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
@@ -1196,6 +1197,75 @@ struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
 }
 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);
 
+/**
+ *      ip6_dst_lookup_tunnel - perform route lookup on tunnel
+ *      @skb: Packet for which lookup is done
+ *      @dev: Tunnel device
+ *      @net: Network namespace of tunnel device
+ *      @sk: Socket which provides route info
+ *      @saddr: Memory to store the src ip address
+ *      @info: Tunnel information
+ *      @protocol: IP protocol
+ *      @use_cahce: Flag to enable cache usage
+ *      This function performs a route lookup on a tunnel
+ *
+ *      It returns a valid dst pointer and stores src address to be used in
+ *      tunnel in param saddr on success, else a pointer encoded error code.
+ */
+
+struct dst_entry *ip6_dst_lookup_tunnel(struct sk_buff *skb,
+					struct net_device *dev,
+					struct net *net,
+					struct socket *sock,
+					struct in6_addr *saddr,
+					const struct ip_tunnel_info *info,
+					u8 protocol,
+					bool use_cache)
+{
+	struct dst_entry *dst = NULL;
+#ifdef CONFIG_DST_CACHE
+	struct dst_cache *dst_cache;
+#endif
+	struct flowi6 fl6;
+	__u8 prio;
+
+#ifdef CONFIG_DST_CACHE
+	dst_cache = (struct dst_cache *)&info->dst_cache;
+	if (use_cache) {
+		dst = dst_cache_get_ip6(dst_cache, saddr);
+		if (dst)
+			return dst;
+	}
+#endif
+	memset(&fl6, 0, sizeof(fl6));
+	fl6.flowi6_mark = skb->mark;
+	fl6.flowi6_proto = protocol;
+	fl6.daddr = info->key.u.ipv6.dst;
+	fl6.saddr = info->key.u.ipv6.src;
+	prio = info->key.tos;
+	fl6.flowlabel = ip6_make_flowinfo(RT_TOS(prio),
+					  info->key.label);
+
+	dst = ipv6_stub->ipv6_dst_lookup_flow(net, sock->sk, &fl6,
+					      NULL);
+	if (IS_ERR(dst)) {
+		netdev_dbg(dev, "no route to %pI6\n", &fl6.daddr);
+		return ERR_PTR(-ENETUNREACH);
+	}
+	if (dst->dev == dev) { /* is this necessary? */
+		netdev_dbg(dev, "circular route to %pI6\n", &fl6.daddr);
+		dst_release(dst);
+		return ERR_PTR(-ELOOP);
+	}
+#ifdef CONFIG_DST_CACHE
+	if (use_cache)
+		dst_cache_set_ip6(dst_cache, dst, &fl6.saddr);
+#endif
+	*saddr = fl6.saddr;
+	return dst;
+}
+EXPORT_SYMBOL_GPL(ip6_dst_lookup_tunnel);
+
 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src,
 					       gfp_t gfp)
 {