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/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 2855b00..7024a87 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -1221,6 +1221,7 @@
 	case IPV6_FLOWLABEL_MGR:
 	{
 		struct in6_flowlabel_req freq;
+		int flags;
 
 		if (len < sizeof(freq))
 			return -EINVAL;
@@ -1232,9 +1233,11 @@
 			return -EINVAL;
 
 		len = sizeof(freq);
+		flags = freq.flr_flags;
+
 		memset(&freq, 0, sizeof(freq));
 
-		val = ipv6_flowlabel_opt_get(sk, &freq);
+		val = ipv6_flowlabel_opt_get(sk, &freq, flags);
 		if (val < 0)
 			return val;