From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eva Kurchatova Date: Fri, 21 Aug 2026 18:20:28 +0300 Subject: [Devel] [PATCH vz10] selftests: mptcp: turn forwarding off in the test namespaces Message-ID: <20260821152029.796830-1-eva.kurchatova@virtuozzo.com> List-Id: A new namespace inherits net.ipv4.ip_forward from the host, so on a host that routes, so do the namespaces these tests build. "invalid address, ADD_ADDR timeout" then reports 0 JOINs where it wants 1. The server announces an unreachable address first and a valid one after it. With forwarding on, the SYN to the unreachable address draws an ICMP error instead of being dropped, so the subflow attempt fails at once and the next ADD_ADDR retransmission starts another one. Every attempt that no longer finds its predecessor bumps add_addr_accepted, so the unreachable address alone uses up both accepted slots and the valid address that follows is dropped without ever getting a subflow. The two tests that do need a router, mptcp_connect.sh and simult_flows.sh, turn forwarding on themselves for those namespaces, so switching it off in the common setup is enough. https://virtuozzo.atlassian.net/browse/VSTOR-139651 Feature: fix selftests Signed-off-by: Eva Kurchatova --- tools/testing/selftests/net/mptcp/mptcp_lib.sh | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/tools/testing/selftests/net/mptcp/mptcp_lib.sh b/tools/testing/selftests/net/mptcp/mptcp_lib.sh index a326f34fc719..43112e1c8c59 100644 --- a/tools/testing/selftests/net/mptcp/mptcp_lib.sh +++ b/tools/testing/selftests/net/mptcp/mptcp_lib.sh @@ -455,6 +455,13 @@ mptcp_lib_ns_init() { local netns for netns in "${@}"; do ip netns exec "${!netns}" sysctl -q net.mptcp.enabled=1 + # The tests that need a router enable forwarding themselves, + # everywhere else it has to be off: a new namespace inherits + # the setting, so on a host that routes, an unreachable + # announced address is answered with an ICMP error instead of + # being silently dropped. + ip netns exec "${!netns}" sysctl -q net.ipv4.ip_forward=0 + ip netns exec "${!netns}" sysctl -q net.ipv6.conf.all.forwarding=0 done } -- 2.55.0