From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	Aleksei Oladko <aleksey.oladko@virtuozzo.com>,
	Ido Schimmel <idosch@nvidia.com>,
	Paolo Abeni <pabeni@redhat.com>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.18 539/641] selftests: forwarding: vxlan_bridge_1d: fix test failure with br_netfilter enabled
Date: Tue, 24 Feb 2026 17:24:25 -0800
Message-ID: <20260225012401.589850494@linuxfoundation.org>
In-Reply-To: <20260225012348.915798704@linuxfoundation.org>
References: <20260225012348.915798704@linuxfoundation.org>
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6.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Aleksei Oladko <aleksey.oladko@virtuozzo.com>

[ Upstream commit 02cb2e6bacbb08ebf6acb61be816efd11e1f4a21 ]

The test generates VXLAN traffic using mausezahn, where the encapsulated
inner IPv4 packet contains a zero IP header checksum. After VXLAN
decapsulation, such packets do not pass sanity checks in br_netfilter
and are dropped, which causes the test to fail.

Fix this by calculating and setting a valid IPv4 header checksum for the
encapsulated packet generated by mausezahn, so that the packet is accepted
by br_netfilter. Fixed by using the payload_template_calc_checksum() /
payload_template_expand_checksum() helpers that are only available
in v6.3 and newer kernels.

Fixes: a0b61f3d8ebf ("selftests: forwarding: vxlan_bridge_1d: Add an ECN decap test")
Signed-off-by: Aleksei Oladko <aleksey.oladko@virtuozzo.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260213131907.43351-2-aleksey.oladko@virtuozzo.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 .../net/forwarding/vxlan_bridge_1d.sh         | 26 ++++++++++++-------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/tools/testing/selftests/net/forwarding/vxlan_bridge_1d.sh b/tools/testing/selftests/net/forwarding/vxlan_bridge_1d.sh
index b43816dd998ca..457f41d5e584b 100755
--- a/tools/testing/selftests/net/forwarding/vxlan_bridge_1d.sh
+++ b/tools/testing/selftests/net/forwarding/vxlan_bridge_1d.sh
@@ -567,6 +567,21 @@ vxlan_encapped_ping_do()
 	local inner_tos=$1; shift
 	local outer_tos=$1; shift
 
+	local ipv4hdr=$(:
+		    )"45:"$(                      : IP version + IHL
+		    )"$inner_tos:"$(              : IP TOS
+		    )"00:54:"$(                   : IP total length
+		    )"99:83:"$(                   : IP identification
+		    )"40:00:"$(                   : IP flags + frag off
+		    )"40:"$(                      : IP TTL
+		    )"01:"$(                      : IP proto
+		    )"CHECKSUM:"$(                : IP header csum
+		    )"c0:00:02:03:"$(             : IP saddr: 192.0.2.3
+		    )"c0:00:02:01"$(              : IP daddr: 192.0.2.1
+		)
+	local checksum=$(payload_template_calc_checksum "$ipv4hdr")
+	ipv4hdr=$(payload_template_expand_checksum "$ipv4hdr" $checksum)
+
 	$MZ $dev -c $count -d 100msec -q \
 		-b $next_hop_mac -B $dest_ip \
 		-t udp tos=$outer_tos,sp=23456,dp=$VXPORT,p=$(:
@@ -577,16 +592,7 @@ vxlan_encapped_ping_do()
 		    )"$dest_mac:"$(               : ETH daddr
 		    )"$(mac_get w2):"$(           : ETH saddr
 		    )"08:00:"$(                   : ETH type
-		    )"45:"$(                      : IP version + IHL
-		    )"$inner_tos:"$(              : IP TOS
-		    )"00:54:"$(                   : IP total length
-		    )"99:83:"$(                   : IP identification
-		    )"40:00:"$(                   : IP flags + frag off
-		    )"40:"$(                      : IP TTL
-		    )"01:"$(                      : IP proto
-		    )"00:00:"$(                   : IP header csum
-		    )"c0:00:02:03:"$(             : IP saddr: 192.0.2.3
-		    )"c0:00:02:01:"$(             : IP daddr: 192.0.2.1
+		    )"$ipv4hdr:"$(                : IPv4 header
 		    )"08:"$(                      : ICMP type
 		    )"00:"$(                      : ICMP code
 		    )"8b:f2:"$(                   : ICMP csum
-- 
2.51.0