selftests: drv-net: add BIG TCP test cases

Add four new test cases that validate coalescing
under increased size limits (BIG TCP):

big_tcp_data_same
  - validates that equal-sized segments coalesce past
   the legacy IP_MAXPACKET limit.
big_tcp_data_lrg_sml
  - validates that a smaller final segment coalesces into the
    previous chain of large-sized segments while crossing the
    IP_MAXPACKET limit.
big_tcp_tcp_seq
  - validates that a packet with a wrong sequence number doesn't
    coalesce. The test uses a sequence number for which the low 16 bits
    correspond to the correct sequence number to validate against
    truncation bugs, since total aggregate length crosses over the
    legacy size limit for BIG TCP.
big_tcp_large_max
  - validates that coalescing stops at the configured BIG TCP limit.

Use a gro_flush_timeout value 2x higher for the BIG TCP test cases
to prevent under-coalescing.

Signed-off-by: Narcisa Vasile <narcisav.kernel@gmail.com>
Link: https://patch.msgid.link/20260913052419.77910-1-narcisav.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions