[PATCH 4.19 41/48] Revert "vxlan: fix tos value before xmit"

Greg Kroah-Hartman
2020-08-10T15:30:58Z

From: Hangbin Liu <liuhangbin@gmail.com>

[ Upstream commit a0dced17ad9dc08b1b25e0065b54c97a318e6e8b ]

This reverts commit 71130f29979c7c7956b040673e6b9d5643003176.

In commit 71130f29979c ("vxlan: fix tos value before xmit") we want to
make sure the tos value are filtered by RT_TOS() based on RFC1349.

0 1 2 3 4 5 6 7
+-----+-----+-----+-----+-----+-----+-----+-----+
| PRECEDENCE | TOS | MBZ |
+-----+-----+-----+-----+-----+-----+-----+-----+

But RFC1349 has been obsoleted by RFC2474. The new DSCP field defined like

0 1 2 3 4 5 6 7
+-----+-----+-----+-----+-----+-----+-----+-----+
| DS FIELD, DSCP | ECN FIELD |
+-----+-----+-----+-----+-----+-----+-----+-----+

So with

IPTOS_TOS_MASK 0x1E
RT_TOS(tos) ((tos)&IPTOS_TOS_MASK)

the first 3 bits DSCP info will get lost.

To take all the DSCP info in xmit, we should revert the patch and just push
all tos bits to ip_tunnel_ecn_encap(), which will handling ECN field later.

Fixes: 71130f29979c ("vxlan: fix tos value before xmit")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Acked-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/vxlan.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -2223,7 +2223,7 @@ static void vxlan_xmit_one(struct sk_buf
ndst = &rt->dst;
skb_tunnel_check_pmtu(skb, ndst, VXLAN_HEADROOM);

- tos = ip_tunnel_ecn_encap(RT_TOS(tos), old_iph, skb);
+ tos = ip_tunnel_ecn_encap(tos, old_iph, skb);
ttl = ttl ? : ip4_dst_hoplimit(&rt->dst);
err = vxlan_build_skb(skb, ndst, sizeof(struct iphdr),
vni, md, flags, udp_sum);
@@ -2260,7 +2260,7 @@ static void vxlan_xmit_one(struct sk_buf

skb_tunnel_check_pmtu(skb, ndst, VXLAN6_HEADROOM);

- tos = ip_tunnel_ecn_encap(RT_TOS(tos), old_iph, skb);
+ tos = ip_tunnel_ecn_encap(tos, old_iph, skb);
ttl = ttl ? : ip6_dst_hoplimit(ndst);
skb_scrub_packet(skb, xnet);
err = vxlan_build_skb(skb, ndst, sizeof(struct ipv6hdr),