From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: "David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>
Cc: "Toke Høiland-Jørgensen" <toke@redhat.com>,
netdev@vger.kernel.org, "Jonathan Morton" <chromatix99@gmail.com>,
"Pete Heist" <pete@heistp.net>
Subject: [PATCH net] inet_ecn: Fix endianness of checksum update when setting ECT(1)
Date: Mon, 30 Nov 2020 19:37:05 +0100 [thread overview]
Message-ID: <20201130183705.17540-1-toke@redhat.com> (raw)
When adding support for propagating ECT(1) marking in IP headers it seems I
suffered from endianness-confusion in the checksum update calculation: In
fact the ECN field is in the *lower* bits of the first 16-bit word of the
IP header when calculating in network byte order. This means that the
addition performed to update the checksum field was wrong; let's fix that.
Fixes: b723748750ec ("tunnel: Propagate ECT(1) when decapsulating as recommended by RFC6040")
Reported-by: Jonathan Morton <chromatix99@gmail.com>
Tested-by: Pete Heist <pete@heistp.net>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
---
include/net/inet_ecn.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/net/inet_ecn.h b/include/net/inet_ecn.h
index e1eaf1780288..563457fec557 100644
--- a/include/net/inet_ecn.h
+++ b/include/net/inet_ecn.h
@@ -107,7 +107,7 @@ static inline int IP_ECN_set_ect1(struct iphdr *iph)
if ((iph->tos & INET_ECN_MASK) != INET_ECN_ECT_0)
return 0;
- check += (__force u16)htons(0x100);
+ check += (__force u16)htons(0x1);
iph->check = (__force __sum16)(check + (check>=0xFFFF));
iph->tos ^= INET_ECN_MASK;
--
2.29.2
next reply other threads:[~2020-11-30 18:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-30 18:37 Toke Høiland-Jørgensen [this message]
2020-12-02 1:24 ` [PATCH net] inet_ecn: Fix endianness of checksum update when setting ECT(1) Jakub Kicinski
2020-12-02 10:07 ` Toke Høiland-Jørgensen
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