Merge branch 'use network helpers, part 1'

Merge branch 'use network helpers, part 1'

Geliang Tang says:

====================
v5:
 - address Martin's comments for v4. (thanks)
 - drop start_server_addr_opts, add opts as a argument of
   start_server_addr.
 - add opts argument for connect_to_addr too.
 - move some patches out of this set, stay with start_server_addr()
   and connect_to_addr() only in it.

v4:
 - add more patches using make_sockaddr and get_socket_local_port
   helpers.

v3:
 - address comments of Martin and Eduard in v2. (thanks)
 - move "int type" to the first argument of start_server_addr and
   connect_to_addr.
 - add start_server_addr_opts.
 - using "sockaddr_storage" instead of "sockaddr".
 - move start_server_setsockopt patches out of this series.

v2:
 - update patch 6 only, fix errors reported by CI.

This patchset uses public helpers start_server_* and connect_to_* defined
in network_helpers.c to drop duplicate code.
====================

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>