selftests/net: fix GRO coalesce test and add ext header coalesce tests

Currently there is no test which checks that IPv6 extension header packets
successfully coalesce. This commit adds a test, which verifies two IPv6
packets with HBH extension headers do coalesce, and another test which
checks that packets with different extension header data do not coalesce
in GRO.

I changed the receive socket filter to accept a packet with one extension
header. This change exposed a bug in the fragment test -- the old BPF did
not accept the fragment packet. I updated correct_num_packets in the
fragment test accordingly.

Signed-off-by: Richard Gobert <richardbgobert@gmail.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/69282fed-2415-47e8-b3d3-34939ec3eb56@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests/net: expand gro with two machine test

The test is currently run on a single host with private addresses,
either over veth or by setting a nic in loopback mode with macvlan.

Support running between two real devices. Allow overriding addresses.

Also cut timeout to fail faster on error and explicitly log success.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

selftests/net: remove ARRAY_SIZE define from individual tests

ARRAY_SIZE is defined in several selftests. Remove definitions from
individual test files and include header file for the define instead.
ARRAY_SIZE define is added in a separate patch to prepare for this
change.

Remove ARRAY_SIZE from net tests and pickup the one defined in
kselftest.h.

Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

selftests/net: GRO coalesce test

Implement a GRO testsuite that expects Linux kernel GRO behavior.
All tests pass with the kernel software GRO stack. Run against a device
with hardware GRO to verify that it matches the software stack.

gro.c generates packets and sends them out through a packet socket. The
receiver in gro.c (run separately) receives the packets on a packet
socket, filters them by destination ports using BPF and checks the
packet geometry to see whether GRO was applied.

gro.sh provides a wrapper to run the gro.c in NIC loopback mode.
It is not included in continuous testing because it modifies network
configuration around a physical NIC: gro.sh sets the NIC in loopback
mode, creates macvlan devices on the physical device in separate
namespaces, and sends traffic generated by gro.c between the two
namespaces to observe coalescing behavior.

GRO coalescing is time sensitive.
Some tests may prove flaky on some hardware.

Note that this test suite tests for software GRO unless hardware GRO is
enabled (ethtool -K $DEV rx-gro-hw on).

To test, run ./gro.sh.
The wrapper will output success or failed test names, and generate
log.txt and stderr.

Sample log.txt result:
...
pure data packet of same size: Test succeeded

large data packets followed by a smaller one: Test succeeded

small data packets followed by a larger one: Test succeeded
...

Sample stderr result:
...
carrier ready
running test ipv4 data
Expected {200 }, Total 1 packets
Received {200 }, Total 1 packets.
...

Signed-off-by: Coco Li <lixiaoyan@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>