vxlan: do not use RT_TOS for IPv6 flowlabel

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2161351
Upstream Status: linux.git

commit e488d4f
Author: Matthias May <matthias.may@westermo.com>
Date:   Fri Aug 5 21:19:04 2022 +0200

    vxlan: do not use RT_TOS for IPv6 flowlabel

    According to Guillaume Nault RT_TOS should never be used for IPv6.

    Quote:
    RT_TOS() is an old macro used to interprete IPv4 TOS as described in
    the obsolete RFC 1349. It's conceptually wrong to use it even in IPv4
    code, although, given the current state of the code, most of the
    existing calls have no consequence.

    But using RT_TOS() in IPv6 code is always a bug: IPv6 never had a "TOS"
    field to be interpreted the RFC 1349 way. There's no historical
    compatibility to worry about.

    Fixes: 1400615 ("vxlan: allow setting ipv6 traffic class")
    Acked-by: Guillaume Nault <gnault@redhat.com>
    Signed-off-by: Matthias May <matthias.may@westermo.com>
    Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Signed-off-by: Guillaume Nault <gnault@redhat.com>

Author: Guillaume Nault

drivers/net/vxlan/vxlan_core.c

@@ -2279,7 +2279,7 @@ static struct dst_entry *vxlan6_get_route(struct vxlan_dev *vxlan,
 	fl6.flowi6_oif = oif;
 	fl6.daddr = *daddr;
 	fl6.saddr = *saddr;
-	fl6.flowlabel = ip6_make_flowinfo(RT_TOS(tos), label);
+	fl6.flowlabel = ip6_make_flowinfo(tos, label);
 	fl6.flowi6_mark = skb->mark;
 	fl6.flowi6_proto = IPPROTO_UDP;
 	fl6.fl6_dport = dport;