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 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.
This patch allows PACKET socket to join a fanout while not RUNNING.
Selftest psock_fanout is extended to test this "fanout while link down"
scenario.
Selftest psock_fanout is also extended to test fanout create/join by
socket that did not bind or specified a protocol, which carries an
implicit bind.
This is the only test that was performed.
Changes:
V03:
* psock_fanout: add test for joining fanout with unbound socket.
* Test that socket can receive packets before adding it to a fanout match.
This is kind of replaces the RUNNING test that was removed.
* Initialize po->ifindex in packet_create. To -1 if no protocol is specified
and add an explicit initialization to 0 if protocol is specified.
* Refactor relevant code in fanout_add within bind_lock, as a sequence of
if {} else if {}, in order to reduce indentation of nested if statements and
provide specific error codes.
V02: https://lore.kernel.org/netdev/cover.1728382839.git.gur.stavi@xxxxxxxxxx
* 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 (3):
af_packet: allow fanout_add when socket is not RUNNING
selftests: net/psock_fanout: socket joins fanout when link is down
selftests: net/psock_fanout: unbound socket fanout
net/packet/af_packet.c | 35 ++++++----
tools/testing/selftests/net/psock_fanout.c | 78 +++++++++++++++++++++-
2 files changed, 96 insertions(+), 17 deletions(-)
base-commit: 36efaca9cb28a893cad98f0448c39a8b698859e2
--
2.45.2
