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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Guillaume Nault <gnault@redhat.com>,
        Matthias May <matthias.may@westermo.com>,
        Jakub Kicinski <kuba@kernel.org>
Subject: [PATCH 4.19 237/287] geneve: do not use RT_TOS for IPv6 flowlabel
Date:   Tue, 23 Aug 2022 10:26:46 +0200
Message-Id: <20220823080109.030375355@linuxfoundation.org>
In-Reply-To: <20220823080100.268827165@linuxfoundation.org>
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From: Matthias May <matthias.may@westermo.com>

commit ca2bb69514a8bc7f83914122f0d596371352416c upstream.

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: 3a56f86f1be6 ("geneve: handle ipv6 priority like ipv4 tos")
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/geneve.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -799,8 +799,7 @@ static struct dst_entry *geneve_get_v6_d
 		use_cache = false;
 	}
 
-	fl6->flowlabel = ip6_make_flowinfo(RT_TOS(prio),
-					   info->key.label);
+	fl6->flowlabel = ip6_make_flowinfo(prio, info->key.label);
 	dst_cache = (struct dst_cache *)&info->dst_cache;
 	if (use_cache) {
 		dst = dst_cache_get_ip6(dst_cache, &fl6->saddr);