ipv4: add new arguments to udp_tunnel_dst_lookup()

We want to make the function more generic so that it can be used by
other UDP tunnel implementations such as geneve and vxlan. To do that,
add the following arguments:

 - source and destination UDP port;
 - ifindex of the output interface, needed by vxlan;
 - the tos, because in some cases it is not taken from struct
   ip_tunnel_info (for example, when it's inherited from the inner
   packet);
 - the dst cache, because not all tunnel types (e.g. vxlan) want to
   use the one from struct ip_tunnel_info.

With these parameters, the function no longer needs the full struct
ip_tunnel_info as argument and we can pass only the relevant part of
it (struct ip_tunnel_key).
Suggested-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Beniamino Galvani <b.galvani@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bareudp.c

@@ -306,8 +306,10 @@ static int bareudp_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 	if (!sock)
 		return -ESHUTDOWN;
 
-	rt = udp_tunnel_dst_lookup(skb, dev, bareudp->net, &saddr, info,
-				   use_cache);
+	rt = udp_tunnel_dst_lookup(skb, dev, bareudp->net, 0, &saddr, &info->key,
+				   0, 0, key->tos,
+				   use_cache ?
+				   (struct dst_cache *)&info->dst_cache : NULL);
 
 	if (IS_ERR(rt))
 		return PTR_ERR(rt);
@@ -483,8 +485,9 @@ static int bareudp_fill_metadata_dst(struct net_device *dev,
 		struct rtable *rt;
 		__be32 saddr;
 
-		rt = udp_tunnel_dst_lookup(skb, dev, bareudp->net, &saddr,
-					   info, use_cache);
+		rt = udp_tunnel_dst_lookup(skb, dev, bareudp->net, 0, &saddr,
+					   &info->key, 0, 0, info->key.tos,
+					   use_cache ? &info->dst_cache : NULL);
 		if (IS_ERR(rt))
 			return PTR_ERR(rt);
 

include/net/udp_tunnel.h

@@ -164,9 +164,11 @@ void udp_tunnel_sock_release(struct socket *sock);
 
 struct rtable *udp_tunnel_dst_lookup(struct sk_buff *skb,
 				     struct net_device *dev,
-				     struct net *net, __be32 *saddr,
-				     const struct ip_tunnel_info *info,
-				     bool use_cache);
+				     struct net *net, int oif,
+				     __be32 *saddr,
+				     const struct ip_tunnel_key *key,
+				     __be16 sport, __be16 dport, u8 tos,
+				     struct dst_cache *dst_cache);
 
 struct metadata_dst *udp_tun_rx_dst(struct sk_buff *skb, unsigned short family,
 				    __be16 flags, __be64 tunnel_id,

net/ipv4/udp_tunnel_core.c

@@ -206,31 +206,31 @@ EXPORT_SYMBOL_GPL(udp_tun_rx_dst);
 
 struct rtable *udp_tunnel_dst_lookup(struct sk_buff *skb,
 				     struct net_device *dev,
-				     struct net *net, __be32 *saddr,
-				     const struct ip_tunnel_info *info,
-				     bool use_cache)
+				     struct net *net, int oif,
+				     __be32 *saddr,
+				     const struct ip_tunnel_key *key,
+				     __be16 sport, __be16 dport, u8 tos,
+				     struct dst_cache *dst_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) {
+	if (dst_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 = IPPROTO_UDP;
-	fl4.daddr = info->key.u.ipv4.dst;
-	fl4.saddr = info->key.u.ipv4.src;
-	tos = info->key.tos;
+	fl4.flowi4_oif = oif;
+	fl4.daddr = key->u.ipv4.dst;
+	fl4.saddr = key->u.ipv4.src;
+	fl4.fl4_dport = dport;
+	fl4.fl4_sport = sport;
 	fl4.flowi4_tos = RT_TOS(tos);
 
 	rt = ip_route_output_key(net, &fl4);
@@ -244,7 +244,7 @@ struct rtable *udp_tunnel_dst_lookup(struct sk_buff *skb,
 		return ERR_PTR(-ELOOP);
 	}
 #ifdef CONFIG_DST_CACHE
-	if (use_cache)
+	if (dst_cache)
 		dst_cache_set_ip4(dst_cache, &rt->dst, fl4.saddr);
 #endif
 	*saddr = fl4.saddr;