[socket-nif] Add (partial) support for socket (level sctp) option associnfo

Added support for the SCTP option ASSOCINFO.

This option is a bit tricky. As the underlying structure (sctp_assocparams)
contains the assoc_id, it begs the question what happens if this option
is fetched for:

   * The own assoc (which means that we might have the assoc id in the
     descriptor and can initiate that part of the struct accordningly).
   * Another assoc: From assoc A asks for info with assoc_id set to
     that of assoc B.
   * The "owning" endpoint.
   * Another endpoint (an endpoint to which the assoc does not belong).

So, if the user calls socket:[getopt|setopt] for an association socket,
shall we require that the assoc_id field is set to -1? Or not set at all
and therefor filled in automatically by the nif-code?

And, if the user calls socket:[getopt|setopt] for an endpoint socket,
shall we require that the assoc_id field is set to a valid id? Or shall
it not be allowed?

Questions, questions...

OTP-14831

1 files changed, 7 insertions, 1 deletions

diff --git a/lib/kernel/test/socket_server.erl b/lib/kernel/test/socket_server.erl
index a9b4aca5f8..56200e0ae9 100644
--- a/lib/kernel/test/socket_server.erl
+++ b/lib/kernel/test/socket_server.erl
@@ -200,8 +200,14 @@ do_manager_init(Domain, seqpacket = Type, sctp = Proto, _Peek) ->
                                {error, R} -> f("error: ~p", [R])
                            end
                  end,
+            %% ok = socket:setopt(Sock, otp, debug, true),
             i("Miscellaneous options: "
-              "~n   disable-fragments: ~s", [GO(disable_fragments)]),
+              "~n   associnfo:         ~s"
+              "~n   autoclose:         ~s"
+              "~n   disable-fragments: ~s", 
+              [GO(associnfo),
+               GO(autoclose),
+               GO(disable_fragments)]),
             Events = #{data_in          => true,
                        association      => true,
                        address          => true,