ipv6: add new arguments to udp_tunnel6_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).

This is similar to what already done for IPv4 in commit 72fc68c6
("ipv4: add new arguments to udp_tunnel_dst_lookup()").
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

@@ -371,8 +371,10 @@ static int bareudp6_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 	if (!sock)
 		return -ESHUTDOWN;
 
-	dst = udp_tunnel6_dst_lookup(skb, dev, bareudp->net, sock, &saddr, info,
-				     use_cache);
+	dst = udp_tunnel6_dst_lookup(skb, dev, bareudp->net, sock, 0, &saddr,
+				     key, 0, 0, key->tos,
+				     use_cache ?
+				     (struct dst_cache *) &info->dst_cache : NULL);
 	if (IS_ERR(dst))
 		return PTR_ERR(dst);
 
@@ -499,7 +501,9 @@ static int bareudp_fill_metadata_dst(struct net_device *dev,
 		struct socket *sock = rcu_dereference(bareudp->sock);
 
 		dst = udp_tunnel6_dst_lookup(skb, dev, bareudp->net, sock,
-					     &saddr, info, use_cache);
+					     0, &saddr, &info->key,
+					     0, 0, info->key.tos,
+					     use_cache ? &info->dst_cache : NULL);
 		if (IS_ERR(dst))
 			return PTR_ERR(dst);
 

include/net/udp_tunnel.h

@@ -172,10 +172,11 @@ struct rtable *udp_tunnel_dst_lookup(struct sk_buff *skb,
 struct dst_entry *udp_tunnel6_dst_lookup(struct sk_buff *skb,
 					 struct net_device *dev,
 					 struct net *net,
-					 struct socket *sock,
+					 struct socket *sock, int oif,
 					 struct in6_addr *saddr,
-					 const struct ip_tunnel_info *info,
-					 bool use_cache);
+					 const struct ip_tunnel_key *key,
+					 __be16 sport, __be16 dport, u8 dsfield,
+					 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/ipv6/ip6_udp_tunnel.c

@@ -119,9 +119,13 @@ EXPORT_SYMBOL_GPL(udp_tunnel6_xmit_skb);
  *      @dev: Tunnel device
  *      @net: Network namespace of tunnel device
  *      @sock: Socket which provides route info
+ *      @oif: Index of the output interface
  *      @saddr: Memory to store the src ip address
- *      @info: Tunnel information
- *      @use_cache: Flag to enable cache usage
+ *      @key: Tunnel information
+ *      @sport: UDP source port
+ *      @dport: UDP destination port
+ *      @dsfield: The traffic class field
+ *      @dst_cache: The dst cache to use for lookup
  *      This function performs a route lookup on a UDP tunnel
  *
  *      It returns a valid dst pointer and stores src address to be used in
@@ -132,20 +136,17 @@ struct dst_entry *udp_tunnel6_dst_lookup(struct sk_buff *skb,
 					 struct net_device *dev,
 					 struct net *net,
 					 struct socket *sock,
+					 int oif,
 					 struct in6_addr *saddr,
-					 const struct ip_tunnel_info *info,
-					 bool use_cache)
+					 const struct ip_tunnel_key *key,
+					 __be16 sport, __be16 dport, u8 dsfield,
+					 struct dst_cache *dst_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) {
+	if (dst_cache) {
 		dst = dst_cache_get_ip6(dst_cache, saddr);
 		if (dst)
 			return dst;
@@ -154,10 +155,12 @@ struct dst_entry *udp_tunnel6_dst_lookup(struct sk_buff *skb,
 	memset(&fl6, 0, sizeof(fl6));
 	fl6.flowi6_mark = skb->mark;
 	fl6.flowi6_proto = IPPROTO_UDP;
-	fl6.daddr = info->key.u.ipv6.dst;
-	fl6.saddr = info->key.u.ipv6.src;
-	prio = info->key.tos;
-	fl6.flowlabel = ip6_make_flowinfo(prio, info->key.label);
+	fl6.flowi6_oif = oif;
+	fl6.daddr = key->u.ipv6.dst;
+	fl6.saddr = key->u.ipv6.src;
+	fl6.fl6_sport = sport;
+	fl6.fl6_dport = dport;
+	fl6.flowlabel = ip6_make_flowinfo(dsfield, key->label);
 
 	dst = ipv6_stub->ipv6_dst_lookup_flow(net, sock->sk, &fl6,
 					      NULL);
@@ -171,7 +174,7 @@ struct dst_entry *udp_tunnel6_dst_lookup(struct sk_buff *skb,
 		return ERR_PTR(-ELOOP);
 	}
 #ifdef CONFIG_DST_CACHE
-	if (use_cache)
+	if (dst_cache)
 		dst_cache_set_ip6(dst_cache, dst, &fl6.saddr);
 #endif
 	*saddr = fl6.saddr;