ipv4: ip_tunnel: Unmask upper DSCP bits in ip_md_tunnel_xmit()

[ Upstream commit c34cfe72bb260fc49660d9e6a9ba95ba01669ae2 ]

Unmask the upper DSCP bits when initializing an IPv4 flow key via
ip_tunnel_init_flow() before passing it to ip_route_output_key() so that
in the future we could perform the FIB lookup according to the full DSCP
value.

Note that the 'tos' variable includes the full DS field. Either the one
specified via the tunnel key or the one inherited from the inner packet.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stable-dep-of: b5a7b661a073 ("net: Fix netns for ip_tunnel_init_flow()")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index d3ad2c424fe9e30c781dc7153971332257498d38..eb74e33ffb64f54184074c51ee3a03a3297db0a1 100644 (file)
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -43,6 +43,7 @@
 #include <net/rtnetlink.h>
 #include <net/udp.h>
 #include <net/dst_metadata.h>
+#include <net/inet_dscp.h>
 
 #if IS_ENABLED(CONFIG_IPV6)
 #include <net/ipv6.h>
@@ -609,9 +610,9 @@ void ip_md_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
                        tos = ipv6_get_dsfield((const struct ipv6hdr *)inner_iph);
        }
        ip_tunnel_init_flow(&fl4, proto, key->u.ipv4.dst, key->u.ipv4.src,
-                           tunnel_id_to_key32(key->tun_id), RT_TOS(tos),
-                           dev_net(dev), 0, skb->mark, skb_get_hash(skb),
-                           key->flow_flags);
+                           tunnel_id_to_key32(key->tun_id),
+                           tos & INET_DSCP_MASK, dev_net(dev), 0, skb->mark,
+                           skb_get_hash(skb), key->flow_flags);
 
        if (!tunnel_hlen)
                tunnel_hlen = ip_encap_hlen(&tun_info->encap);