[PATCH net 0/2] selftests: net: more pmtu.sh fixes

[PATCH net 0/2] selftests: net: more pmtu.sh fixes

[Paolo Abeni]

The mentioned test is still flaky, unusally enough in 'fast'
environments.

Patch 2/2 [try to] address the existing issues, while patch 1/2
introduces more strict tests for the existing net helpers, to hopefully
prevent future pain.

Paolo Abeni (2):
  selftests: net: more strict check in net_helper
  selftests: net: more pmtu.sh fixes

 tools/testing/selftests/net/net_helper.sh | 11 +++++++----
 tools/testing/selftests/net/pmtu.sh       |  4 ++--
 2 files changed, 9 insertions(+), 6 deletions(-)

-- 
2.43.0

[PATCH net 1/2] selftests: net: more strict check in net_helper

[Paolo Abeni]

The helper waiting for a listener port can match any socket whose
hexadecimal representation of source or destination addresses
matches that of the given port.

Additionally, any socket state is accepted.

All the above can let the helper return successfully before the
relevant listener is actually ready, with unexpected results.

So far I could not find any related failure in the netdev CI, but
the next patch is going to make the critical event more easily
reproducible.

Address the issue matching the port hex only vs the relevant socket
field and additionally checking the socket state for TCP sockets.

Fixes: 3bdd9fd29cb0 ("selftests/net: synchronize udpgro tests' tx and rx connection")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 tools/testing/selftests/net/net_helper.sh | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/net/net_helper.sh b/tools/testing/selftests/net/net_helper.sh
index 4fe0befa13fb..6596fe03c77f 100644
--- a/tools/testing/selftests/net/net_helper.sh
+++ b/tools/testing/selftests/net/net_helper.sh
@@ -8,13 +8,16 @@ wait_local_port_listen()
 	local listener_ns="${1}"
 	local port="${2}"
 	local protocol="${3}"
-	local port_hex
+	local pattern
 	local i
 
-	port_hex="$(printf "%04X" "${port}")"
+	pattern=":$(printf "%04X" "${port}") "
+
+	# for tcp protocol additionally check the socket state
+	[ ${protocol} = "tcp" ] && pattern="${pattern}0A"
 	for i in $(seq 10); do
-		if ip netns exec "${listener_ns}" cat /proc/net/"${protocol}"* | \
-		   grep -q "${port_hex}"; then
+		if ip netns exec "${listener_ns}" awk '{print $2" "$4}' \
+		   /proc/net/"${protocol}"* | grep -q "${pattern}"; then
 			break
 		fi
 		sleep 0.1
-- 
2.43.0

[PATCH net 2/2] selftests: net: more pmtu.sh fixes

[Paolo Abeni]

The netdev CI is reporting failures for the pmtu test:

  [  115.929264] br0: port 2(vxlan_a) entered forwarding state
  # 2024/02/08 17:33:22 socat[7871] E bind(7, {AF=10 [0000:0000:0000:0000:0000:0000:0000:0000]:50000}, 28): Address already in use
  # 2024/02/08 17:33:22 socat[7877] E write(7, 0x5598fb6ff000, 8192): Connection refused
  # TEST: IPv6, bridged vxlan4: PMTU exceptions                         [FAIL]
  # File size 0 mismatches exepcted value in locally bridged vxlan test

The root cause is apparently a socket created by a previous iteration
of the relevant loop still lasting in LAST_ACK state.

Note that even the file size check is racy, the receiver process dumping
the file could still be running in background

Allow the listener to bound on the same local port via SO_REUSEADDR and
collect file output file size only after the listener completion.

Fixes: 136a1b434bbb ("selftests: net: test vxlan pmtu exceptions with tcp")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 tools/testing/selftests/net/pmtu.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/net/pmtu.sh b/tools/testing/selftests/net/pmtu.sh
index d65fdd407d73..cfc84958025a 100755
--- a/tools/testing/selftests/net/pmtu.sh
+++ b/tools/testing/selftests/net/pmtu.sh
@@ -1336,16 +1336,16 @@ test_pmtu_ipvX_over_bridged_vxlanY_or_geneveY_exception() {
 		else
 			TCPDST="TCP:[${dst}]:50000"
 		fi
-		${ns_b} socat -T 3 -u -6 TCP-LISTEN:50000 STDOUT > $tmpoutfile &
+		${ns_b} socat -T 3 -u -6 TCP-LISTEN:50000,reuseaddr STDOUT > $tmpoutfile &
 		local socat_pid=$!
 
 		wait_local_port_listen ${NS_B} 50000 tcp
 
 		dd if=/dev/zero status=none bs=1M count=1 | ${target} socat -T 3 -u STDIN $TCPDST,connect-timeout=3
 
+		wait ${socat_pid}
 		size=$(du -sb $tmpoutfile)
 		size=${size%%/tmp/*}
-		wait ${socat_pid}
 
 		[ $size -ne 1048576 ] && err "File size $size mismatches exepcted value in locally bridged vxlan test" && return 1
 	done
-- 
2.43.0

Re: [PATCH net 0/2] selftests: net: more pmtu.sh fixes

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Mon, 12 Feb 2024 11:19:22 +0100 you wrote:
> The mentioned test is still flaky, unusally enough in 'fast'
> environments.
> 
> Patch 2/2 [try to] address the existing issues, while patch 1/2
> introduces more strict tests for the existing net helpers, to hopefully
> prevent future pain.
> 
> [...]

Here is the summary with links:
  - [net,1/2] selftests: net: more strict check in net_helper
    https://git.kernel.org/netdev/net/c/a71d0908e32f
  - [net,2/2] selftests: net: more pmtu.sh fixes
    https://git.kernel.org/netdev/net/c/20622dc934e1

You are awesome, thank you!
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