selftests: net: cover UDP splice checksum fragment alignment

Exercise software UDP checksums when splice() transfers multiple pipe
fragments into a corked datagram. Use separate source pipes so short writes
cannot merge, and use odd fragment lengths to expose checksum-position
errors between fragments.

Cover IPv4, IPv6 and IPv4-mapped destinations, connected and unconnected
sockets, resident prefixes, even and odd fragment lengths, and a fragment
starting near a page boundary. Ordinary sends provide a control. Check the
complete payload and reject extra datagrams after a successful send.

Keep receive waits bounded and skip unavailable address families or pipe
capacities. The test uses only loopback sockets with ephemeral ports and
has no dependency on the application that exposed the regression.

Signed-off-by: Alireza Asgari <alireza@asgari.net>
Link: https://patch.msgid.link/20260924-fix-udp-splice-checksum-v1-2-fe61d65447a8@asgari.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions