ipv6: change ipv6_stub_impl.ipv6_dst_lookup to take net argument

This patch adds net argument to ipv6_stub_impl.ipv6_dst_lookup
for use cases where sk is not available (like mpls).
sk appears to be needed to get the namespace 'net' and is optional
otherwise. This patch series changes ipv6_stub_impl.ipv6_dst_lookup
to take net argument. sk remains optional.

All callers of ipv6_stub_impl.ipv6_dst_lookup have been modified
to pass net. I have modified them to use already available
'net' in the scope of the call. I can change them to
sock_net(sk) to avoid any unintended change in behaviour if sock
namespace is different. They dont seem to be from code inspection.

Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index c5fc852..92b7cf0 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -881,10 +881,9 @@
 	return dst;
 }
 
-static int ip6_dst_lookup_tail(struct sock *sk,
+static int ip6_dst_lookup_tail(struct net *net, struct sock *sk,
 			       struct dst_entry **dst, struct flowi6 *fl6)
 {
-	struct net *net = sock_net(sk);
 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 	struct neighbour *n;
 	struct rt6_info *rt;
@@ -994,10 +993,11 @@
  *
  *	It returns zero on success, or a standard errno code on error.
  */
-int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi6 *fl6)
+int ip6_dst_lookup(struct net *net, struct sock *sk, struct dst_entry **dst,
+		   struct flowi6 *fl6)
 {
 	*dst = NULL;
-	return ip6_dst_lookup_tail(sk, dst, fl6);
+	return ip6_dst_lookup_tail(net, sk, dst, fl6);
 }
 EXPORT_SYMBOL_GPL(ip6_dst_lookup);
 
@@ -1018,7 +1018,7 @@
 	struct dst_entry *dst = NULL;
 	int err;
 
-	err = ip6_dst_lookup_tail(sk, &dst, fl6);
+	err = ip6_dst_lookup_tail(sock_net(sk), sk, &dst, fl6);
 	if (err)
 		return ERR_PTR(err);
 	if (final_dst)
@@ -1052,7 +1052,7 @@
 
 	dst = ip6_sk_dst_check(sk, dst, fl6);
 
-	err = ip6_dst_lookup_tail(sk, &dst, fl6);
+	err = ip6_dst_lookup_tail(sock_net(sk), sk, &dst, fl6);
 	if (err)
 		return ERR_PTR(err);
 	if (final_dst)