net sched: Pass the skb into change so it can access NETLINK_CB

cls_flow.c plays with uids and gids.  Unless I misread that
code it is possible for classifiers to depend on the specific uid and
gid values.  Therefore I need to know the user namespace of the
netlink socket that is installing the packet classifiers.  Pass
in the rtnetlink skb so I can access the NETLINK_CB of the passed
packet.  In particular I want access to sk_user_ns(NETLINK_CB(in_skb).ssk).

Pass in not the user namespace but the incomming rtnetlink skb into
the the classifier change routines as that is generally the more useful
parameter.

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
diff --git a/net/sched/cls_tcindex.c b/net/sched/cls_tcindex.c
index fe29420..a1293b4 100644
--- a/net/sched/cls_tcindex.c
+++ b/net/sched/cls_tcindex.c
@@ -332,7 +332,8 @@
 }
 
 static int
-tcindex_change(struct tcf_proto *tp, unsigned long base, u32 handle,
+tcindex_change(struct sk_buff *in_skb,
+	       struct tcf_proto *tp, unsigned long base, u32 handle,
 	       struct nlattr **tca, unsigned long *arg)
 {
 	struct nlattr *opt = tca[TCA_OPTIONS];