Escalus uses fast_tls instead of ssl

The biggest magic is on the `escalus_ctp: tcp_to_tls/2` helper function.
Fast_tls has a pretty much hacky and undocumented way to setup client
connections, which is nothing but ugly. Anyway, that's the way it works.

rebar.config

@@ -13,7 +13,8 @@
         {bbmustache, "1.8.0"},
         {uuid, "1.7.5", {pkg, uuid_erl}},
         {gun, "1.3.1"},
-        {worker_pool, "3.2.0"}
+        {worker_pool, "3.2.0"},
+        {fast_tls, {git, "https://github.com/processone/fast_tls.git", {ref, "a0fe32d"}}}
 ]}.
 
 {relx, [{release, {escalus, "0.0.1"},

rebar.lock

@@ -9,12 +9,17 @@
   {git,"https://github.com/esl/exml.git",
        {ref,"a307e83669ad0a8d96ea3f2be9da36417efb94fc"}},
   0},
+ {<<"fast_tls">>,
+  {git,"https://github.com/processone/fast_tls.git",
+       {ref,"a0fe32dcac2ea0ae3d282269a081f627423e6ae4"}},
+  0},
  {<<"fusco">>,
   {git,"https://github.com/esl/fusco.git",
        {ref,"0a428471aefb3a38207c2141249181e6c018e565"}},
   0},
  {<<"gun">>,{pkg,<<"gun">>,<<"1.3.1">>},0},
  {<<"meck">>,{pkg,<<"meck">>,<<"0.8.13">>},0},
+ {<<"p1_utils">>,{pkg,<<"p1_utils">>,<<"1.0.18">>},1},
  {<<"quickrand">>,{pkg,<<"quickrand">>,<<"1.7.5">>},1},
  {<<"uuid">>,{pkg,<<"uuid_erl">>,<<"1.7.5">>},0},
  {<<"worker_pool">>,{pkg,<<"worker_pool">>,<<"3.2.0">>},0}]}.
@@ -24,6 +29,7 @@
  {<<"cowlib">>, <<"8AA629F81A0FC189F261DC98A42243FA842625FEEA3C7EC56C48F4CCDB55490F">>},
  {<<"gun">>, <<"1489FD96018431B89F401041A9CE0B02B45265247F0FDCF71273BF087C64EA4F">>},
  {<<"meck">>, <<"FFEDB39F99B0B99703B8601C6F17C7F76313EE12DE6B646E671E3188401F7866">>},
+ {<<"p1_utils">>, <<"3FE224DE5B2E190D730A3C5DA9D6E8540C96484CF4B4692921D1E28F0C32B01C">>},
  {<<"quickrand">>, <<"E3086A153EB13A057FC19192D05E2D4C6BB2BDBB55746A699BEAE9847AC17CA8">>},
  {<<"uuid">>, <<"3862FF9A21C42566DFD0376B97512FA202922897129E09A05E2AFA0D9CAFD97A">>},
  {<<"worker_pool">>, <<"54DD752BA4CA4B702124C45803AA958B36BCE77D683B87886606F1AADA3E124D">>}]}

src/escalus.app.src

@@ -13,7 +13,8 @@
                   gun,
                   meck,
                   bbmustache,
-                  uuid
+                  uuid,
+                  fast_tls
                  ]},
   {maintainers, ["ESL"]},
   {licenses, ["Apache 2.0"]},

src/escalus_tcp.erl

@@ -220,11 +220,11 @@ handle_call({upgrade_to_tls, SSLOpts}, _From, #state{socket = Socket} = State) -
     SSLOpts1 = [{reuse_sessions, true}],
     SSLOpts2 = lists:keymerge(1, lists:keysort(1, SSLOpts),
                               lists:keysort(1, SSLOpts1)),
-    case ssl:connect(Socket, SSLOpts2) of
-        {ok, Socket2} ->
+    inet:setopts(Socket, [{active, false}]),
+    case tcp_to_tls(Socket, SSLOpts2) of
+        {ok, TlsSocket} ->
             {ok, Parser} = exml_stream:new_parser(),
-            {reply, Socket2,
-             State#state{socket = Socket2, parser = Parser, ssl=true}};
+            {reply, TlsSocket, State#state{socket = TlsSocket, parser = Parser, ssl = true}};
         {error, _} = E ->
             {reply, E, State}
     end;
@@ -248,7 +248,7 @@ handle_call({set_filter_pred, Pred}, _From, State) ->
     {reply, ok, State#state{filter_pred = Pred}};
 handle_call(kill_connection, _, #state{socket = Socket, ssl = SSL} = S) ->
     case SSL of
-        true -> ssl:close(Socket);
+        true -> fast_tls:close(Socket);
         false -> gen_tcp:close(Socket)
     end,
     close_compression_streams(S#state.compress),
@@ -276,8 +276,11 @@ handle_cast(stop, State) ->
 handle_info({tcp, Socket, Data}, #state{socket = Socket, ssl = false} = State) ->
     NewState = handle_data(Socket, Data, State),
     {noreply, NewState};
-handle_info({ssl, Socket, Data}, #state{socket = Socket, ssl = true} = State) ->
-    NewState = handle_data(Socket, Data, State),
+handle_info({tcp, TcpSocket, Data},
+            #state{socket = {tlssock, TcpSocket, _} = TlsSocket, ssl = true} = State) ->
+    % This means we're on fast_tls
+    {ok, NewData} = fast_tls:recv_data(TlsSocket, Data),
+    NewState = handle_data(TlsSocket, NewData, State),
     {noreply, NewState};
 handle_info({tcp_closed, _Socket}, #state{} = State) ->
     {stop, normal, State};
@@ -293,7 +296,7 @@ handle_info(_, State) ->
 -spec terminate(term(), state()) -> term().
 terminate(Reason, #state{socket = Socket, ssl = true} = State) ->
     common_terminate(Reason, State),
-    ssl:close(Socket);
+    fast_tls:close(Socket);
 terminate(Reason, #state{socket = Socket} = State) ->
     common_terminate(Reason, State),
     gen_tcp:close(Socket).
@@ -348,7 +351,7 @@ set_active_opt(#state{ssl = SSL, socket = Soc} = State, at_least_once) ->
 
 
 set_active_opt(true, Socket, true) ->
-    ssl:setopts(Socket, [{active, once}]);
+    fast_tls:setopts(Socket, [{active, once}]);
 set_active_opt(false, Socket, true) ->
     inet:setopts(Socket, [{active, once}]);
 set_active_opt(_,_,_) ->
@@ -444,7 +447,7 @@ maybe_compress_and_send(Data, State) ->
     raw_send(Data, State).
 
 raw_send(Data, #state{socket = Socket, ssl = true}) ->
-    ssl:send(Socket, Data);
+    fast_tls:send(Socket, Data);
 raw_send(Data, #state{socket = Socket}) ->
     gen_tcp:send(Socket, Data).
 
@@ -506,10 +509,25 @@ do_connect(#{ssl        := IsSSLConn,
     Reply.
 
 maybe_ssl_connection(true, Address, Port, SocketOpts, SSLOpts) ->
-    ssl:connect(Address, Port, SocketOpts ++ SSLOpts);
+    {ok, Socket} = gen_tcp:connect(Address, Port, SocketOpts),
+    tcp_to_tls(Socket, SSLOpts);
 maybe_ssl_connection(_, Address, Port, SocketOpts, _) ->
     gen_tcp:connect(Address, Port, SocketOpts).
 
+tcp_to_tls(GenTcpSocket, SSLOpts) ->
+    inet:setopts(GenTcpSocket, [{active, false}]),
+    case fast_tls:tcp_to_tls(GenTcpSocket, [connect | SSLOpts]) of
+        {ok, TlsSocket} ->
+            %% fast_tls requires dummy recv_data/2 call to accomplish TLS handshake
+            fast_tls:recv(TlsSocket, 0, 100),
+            fast_tls:recv_data(TlsSocket, <<>>),
+            fast_tls:recv_data(TlsSocket, <<>>),
+            fast_tls:setopts(TlsSocket, [{active, once}]),
+            {ok, TlsSocket};
+        {error, _} = E ->
+            E
+    end.
+
 %%===================================================================
 %%% Init options parsing helpers
 %%%===================================================================

src/escalus_tcp.hrl

@@ -15,7 +15,7 @@
 %%==============================================================================
 
 -record(state, {owner,
-                socket,
+                socket :: gen_tcp:socket() | fast_tls:tls_socket(),
                 parser,
                 filter_pred,
                 ssl = false,