selftests: mptcp: add MPTCP_FULL_INFO testcase

Add a testcase explicitly triggering the newly introduce
MPTCP_FULL_INFO getsockopt.

Link: https://github.com/multipath-tcp/mptcp_net-next/issues/388
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: mptcp: explicitly tests aggregate counters

Update the existing sockopt test-case to do some basic checks
on the newly added counters.

Link: https://github.com/multipath-tcp/mptcp_net-next/issues/385
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: mptcp: sockopt: relax expected returned size

Selftests are supposed to run on any kernels, including the old ones not
supporting all MPTCP features.

One of them is the getsockopt(SOL_MPTCP) to get info about the MPTCP
connections introduced by commit 55c42fa7fa33 ("mptcp: add MPTCP_INFO
getsockopt") and the following ones.

We cannot guess in advance which sizes the kernel will returned: older
kernel can returned smaller sizes, e.g. recently the tcp_info structure
has been modified in commit 71fc704768f6 ("tcp: add rcv_wnd and
plb_rehash to TCP_INFO") where a new field has been added.

The userspace can also expect a smaller size if it is compiled with old
uAPI kernel headers.

So for these sizes, we can only check if they are above a certain
threshold, 0 for the moment. We can also only compared sizes with the
ones set by the kernel.

Link: https://github.com/multipath-tcp/mptcp_net-next/issues/368
Fixes: ce9979129a0b ("selftests: mptcp: add mptcp getsockopt test cases")
Cc: stable@vger.kernel.org
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: mptcp: Initialize variables to quiet gcc 12 warnings

In a few MPTCP selftest tools, gcc 12 complains that the 'sock' variable
might be used uninitialized. This is a false positive because the only
code path that could lead to uninitialized access is where getaddrinfo()
fails, but the local xgetaddrinfo() wrapper exits if such a failure
occurs.

Initialize the 'sock' variable anyway to allow the tools to build with
gcc 12.

Fixes: 048d19d444be ("mptcp: add basic kselftest for mptcp")
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: mptcp: check IP_TOS in/out are the same

Check that getsockopt(IP_TOS) returns what setsockopt(IP_TOS) did set
right before.

Also check that socklen_t == 0 and -1 input values match those
of normal tcp sockets.

Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: mptcp: add mptcp getsockopt test cases

Add a test program that retrieves the three info types:
1. mptcp meta information
2. tcp info for subflow
3. subflow endpoint addresses

For all three rudimentary checks are added.

1. Meta information checks that the logical mptcp
sequence numbers advance as expected, based on the bytes read
(init seq + bytes_received/sent) and the connection state
(after close, we should exect 1 extra byte due to FIN).

2. TCP info checks the number of bytes sent/received vs.
sums of read/write syscall return values.

3. Subflow endpoint addresses are checked vs. getsockname/getpeername
result.

Tests for forward compatibility (0-initialisation of output-only
fields in mptcp_subflow_data structure) are added as well.

Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>