S2S/out rework

[NelsonVides]

The first important changes to notice are those in mongoose_xmpp_socket; it adds:

• API for the client side for connecting a new socket (whether TLS or not),
• API for the client side upgrading a tcp socket to a TLS one.

---

The next big thing is the mongoose_addr_list module. It uses inet_res:lookup/5 alone to implement DNS discovery as required in the documents below, and also encapsulates preparing all data necessary to know where to connect to. It is currently used by s2s alone, but so much of the logic could be reused by a client by minimal extensions to this module. I'm not implementing the client side of it in this rework though.

• RFC6120 §3.2: Resolution of Fully Qualified Domain Names,
• And also as described by the XEP-0368: SRV records for XMPP over TLS extension.

---

Next, the actual big thing: replace s2s_out modules with a new gen_statem based mongoose_s2s_out module.

• Dialback is still inside, but better separated which process will be an outgoing connection and which one will be just a dialback, and dialback processes are now actually terminated.
• There's so much similar code now in s2s_out, s2s_in, component_connection, and c2s, that it is left to wonder to what extend it can be further unified and to what extend it is just a consistent pattern :)

---

At last, many related minor changes are scattered around code, like:

• Optimisations on mongoose_s2s_dialback (exml attrs matching),
• Optimisations on mongoose_s2s_lib (avoid binary<->string back-nd-forth conversions if not needed),
• Typing information in ejabberd_s2s (more explicit binary shapes than just binary).

[codecov]

Codecov Report

Attention: Patch coverage is 82.09366% with 65 lines in your changes missing coverage. Please review.

Project coverage is 85.64%. Comparing base (a610a89) to head (e70c80a).
Report is 20 commits behind head on feature/listeners.

Files with missing lines	Patch %	Lines
src/s2s/mongoose_s2s_out.erl	76.81%	48 Missing ⚠️
src/mongoose_addr_list.erl	91.13%	7 Missing ⚠️
src/listeners/mongoose_xmpp_socket.erl	85.71%	3 Missing ⚠️
src/mod_bosh_socket.erl	0.00%	2 Missing ⚠️
src/mod_websockets.erl	0.00%	2 Missing ⚠️
src/cert_utils.erl	0.00%	1 Missing ⚠️
src/config/mongoose_config_spec.erl	80.00%	1 Missing ⚠️
src/s2s/ejabberd_s2s.erl	91.66%	1 Missing ⚠️

Additional details and impacted files

@@                  Coverage Diff                  @@
##           feature/listeners    #4479      +/-   ##
=====================================================
+ Coverage              85.48%   85.64%   +0.15%     
=====================================================
  Files                    558      558              
  Lines                  33971    33754     -217     
=====================================================
- Hits                   29041    28907     -134     
+ Misses                  4930     4847      -83     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[DenysGonchar]

looks very good but some minor comments must be addressed.

[mongoose-im]

elasticsearch_and_cassandra_27 / elasticsearch_and_cassandra_mnesia / e70c80a
Reports root/ big
OK: 683 / Failed: 0 / User-skipped: 72 / Auto-skipped: 0

---

small_tests_26 / small_tests / e70c80a
Reports root / small

---

small_tests_27 / small_tests / e70c80a
Reports root / small

---

small_tests_27_arm64 / small_tests / e70c80a
Reports root / small

---

dynamic_domains_mysql_redis_27 / mysql_redis / e70c80a
Reports root/ big
OK: 4809 / Failed: 0 / User-skipped: 154 / Auto-skipped: 0

---

ldap_mnesia_27 / ldap_mnesia / e70c80a
Reports root/ big
OK: 2297 / Failed: 0 / User-skipped: 1022 / Auto-skipped: 0

---

ldap_mnesia_26 / ldap_mnesia / e70c80a
Reports root/ big
OK: 2297 / Failed: 0 / User-skipped: 1007 / Auto-skipped: 0

---

internal_mnesia_27 / internal_mnesia / e70c80a
Reports root/ big
OK: 2431 / Failed: 0 / User-skipped: 888 / Auto-skipped: 0

---

dynamic_domains_pgsql_mnesia_27 / pgsql_mnesia / e70c80a
Reports root/ big
OK: 4844 / Failed: 0 / User-skipped: 119 / Auto-skipped: 0

---

dynamic_domains_mssql_mnesia_27 / odbc_mssql_mnesia / e70c80a
Reports root/ big
OK: 4839 / Failed: 0 / User-skipped: 124 / Auto-skipped: 0

---

dynamic_domains_pgsql_mnesia_26 / pgsql_mnesia / e70c80a
Reports root/ big
OK: 4829 / Failed: 0 / User-skipped: 119 / Auto-skipped: 0

---

pgsql_cets_27 / pgsql_cets / e70c80a
Reports root/ big
OK: 4916 / Failed: 0 / User-skipped: 188 / Auto-skipped: 0

---

pgsql_mnesia_26 / pgsql_mnesia / e70c80a
Reports root/ big
OK: 5204 / Failed: 0 / User-skipped: 128 / Auto-skipped: 0

---

pgsql_mnesia_27 / pgsql_mnesia / e70c80a
Reports root/ big
OK: 5219 / Failed: 0 / User-skipped: 128 / Auto-skipped: 0

---

cockroachdb_cets_27 / cockroachdb_cets / e70c80a
Reports root/ big
OK: 4916 / Failed: 0 / User-skipped: 188 / Auto-skipped: 0

---

mysql_redis_27 / mysql_redis / e70c80a
Reports root/ big
OK: 5197 / Failed: 1 / User-skipped: 149 / Auto-skipped: 0

accounts_SUITE:register:already_registered

{error,
  {timeout_when_waiting_for_stanza,
    [{escalus_client,wait_for_stanza,
       [{client,<<"alice_already_registered_25@localhost/res1">>,
          escalus_tcp,<0.1376.0>,
          [{event_manager,<0.1342.0>},
           {server,<<"localhost">>},
           {username,<<"alicE_already_registered_25">>},
           {resource,<<"res1">>}],
          [{event_client,
             [{event_manager,<0.1342.0>},
            {server,<<"localhost">>},
            {username,<<"alicE_already_registered_25">>},
            {resource,<<"res1">>}]},
           {resource,<<"res1">>},
           {username,<<"alice_already_registered_25">>},
           {server,<<"localhost">>},
           {host,<<"localhost">>},
           {port,5222},
           {auth,fun escalus_auth:auth_plain/2},
           {wspath,undefined},
           {username,<<"alicE_already_registered_25">>},
           {server,<<"localhost">>},
           {password,<<"matygrysa">>},
           {stream_id,<<"9282954657ca95a3">>}]},
        5000],
       [{file,
          "/home/circleci/project/big_tests/_build/default/lib/escalus/src/escalus_client.erl"},
        {line,136}]},
     {accounts_SUITE,already_registered_story,1,
       [{file,
          "/home/circleci/project/big_tests/tests/accounts_SUITE.erl"},
        {line,198}]},
     {escalus_story,story,4,
       [{file,
          "/home/circleci/project/big_tests/_build/default/lib/escalus/src/escalus_story.erl"},
        {line,75}]},
     {test_server,ts_tc,3,[{file...

Report log

---

mssql_mnesia_27 / odbc_mssql_mnesia / e70c80a
Reports root/ big
OK: 5214 / Failed: 0 / User-skipped: 133 / Auto-skipped: 0

---

mysql_redis_27 / mysql_redis / e70c80a
Reports root/ big
OK: 20 / Failed: 0 / User-skipped: 0 / Auto-skipped: 0

[DenysGonchar]

Thanks