ipv4: netfilter: Unmask upper DSCP bits in ip_route_me_harder()

Unmask the upper DSCP bits when calling ip_route_output_key() so that in
the future it could perform the FIB lookup according to the full DSCP
value.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/netfilter.c

@@ -14,6 +14,7 @@
 #include <net/route.h>
 #include <net/xfrm.h>
 #include <net/ip.h>
+#include <net/inet_dscp.h>
 #include <net/netfilter/nf_queue.h>
 
 /* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */
@@ -43,7 +44,7 @@ int ip_route_me_harder(struct net *net, struct sock *sk, struct sk_buff *skb, un
 	 */
 	fl4.daddr = iph->daddr;
 	fl4.saddr = saddr;
-	fl4.flowi4_tos = RT_TOS(iph->tos);
+	fl4.flowi4_tos = iph->tos & INET_DSCP_MASK;
 	fl4.flowi4_oif = sk ? sk->sk_bound_dev_if : 0;
 	fl4.flowi4_l3mdev = l3mdev_master_ifindex(dev);
 	fl4.flowi4_mark = skb->mark;