ipv6: add a flag to get the flow label used remotly

This information is already available via IPV6_FLOWINFO
of IPV6_2292PKTOPTIONS, and them a filtering to get the flow label
information. But it is probably logical and easier for users to add this
here, and to control both sent/received flow label values with the
IPV6_FLOWLABEL_MGR option.

Signed-off-by: Florent Fourcot <florent.fourcot@enst-bretagne.fr>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 6d80f51..78d3d51 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -253,7 +253,8 @@
 					 struct ipv6_txoptions *fopt);
 void fl6_free_socklist(struct sock *sk);
 int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen);
-int ipv6_flowlabel_opt_get(struct sock *sk, struct in6_flowlabel_req *freq);
+int ipv6_flowlabel_opt_get(struct sock *sk, struct in6_flowlabel_req *freq,
+			   int flags);
 int ip6_flowlabel_init(void);
 void ip6_flowlabel_cleanup(void);