PACKET socket can retain its fanout membership through link down and up and leave a fanout while closed regardless of link state. However, socket was forbidden from joining a fanout while it was not RUNNING. This patch allows PACKET socket to join a fanout while not RUNNING. Selftest psock_fanout is extended to test this scenario. This is the only test that was performed. This scenario was identified while studying DPDK pmd_af_packet_drv. Since sockets are only created during initialization, there is no reason to fail the initialization if a single link is temporarily down. I hope it is not considered as breaking user space and that applications are not designed to expect this failure. Changes: V02: * psock_fanout: use explicit loopback up/down instead of toggle. * psock_fanout: don't try to restore loopback state on failure. * Rephrase commit message about "leaving a fanout". V01: https://lore.kernel.org/netdev/cover.1728303615.git.gur.stavi@xxxxxxxxxx/ Gur Stavi (2): af_packet: allow fanout_add when socket is not RUNNING selftests: net/psock_fanout: socket joins fanout when link is down net/packet/af_packet.c | 10 +++--- tools/testing/selftests/net/psock_fanout.c | 42 ++++++++++++++++++++-- 2 files changed, 44 insertions(+), 8 deletions(-) base-commit: f95b4725e796b12e5f347a0d161e1d3843142aa8 -- 2.45.2
