[PATCH mptcp-next v3 0/5] Add 'dump_subflow' test in selftests

[Gang Yan <yangang@kylinos.cn>]

The 'subflow_get_info_size' is called only in 'inet_sk_attr_size', and
the only calltrace is that 'tcp_diag_dump_one'->'inet_diag_dump_one_icsk'
->'inet_sk_attr_size'.

So It's necessary to add 'get_subflow_info' in mptcp_diag.c to cover this
function. Given a specific TCP connection, it is possible to judge if
it is a MPTCP subflow by 'INET_ULP_INFO_MPTCP' and print 'subflow_info'.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/524

------
Changelog
  v2:
    - Fix the CI compiling error.
  v3:
    - Set idaig_ext when 'r' is declared.
    - Declare iovlen to 0, and adjust the increment logic.
    - Squash patch 3 into patch 4.
    - Rename 'subflow_addr' to 'subflow_addrs'
    - Remove the comment and declare [ad]ddr on the same line.
    - Set id.idiag_cookie[0/1] when r is declared.
    - Remove the 'id.idiag_if = 0' because the default value is 0.
    - Squash patch 6 into patch 5.
    - Add the example of output in commit message.
    - Adjust the input of 'mptcp_diag -s' to "saddr:sport daddr:dport"
      to save a few lines in diag.sh
    - In diag.sh, use "mptcp_diag -s '$subflow_line'" instead of
      the old version, and call 'ss' only once to ensure the safety.
    - Fix some error/check/warning problems in CI.
    - Put the link of issue into the commit message of patch 5.

Gang Yan (5):
  selftests: mptcp: add struct params in mptcp_diag
  selftests: mptcp: refactor send_query parameters for code clarity
  selftests: mptcp: refactor NLMSG handling with 'proto'
  selftests: mptcp: add helpers to get subflow_info
  selftests: mptcp: add chk_sublfow in diag.sh

 tools/testing/selftests/net/mptcp/diag.sh     |  33 +++
 .../testing/selftests/net/mptcp/mptcp_diag.c  | 228 +++++++++++++++---
 2 files changed, 229 insertions(+), 32 deletions(-)

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2.43.0