Fix SSL accept blocking the main acceptor

examples/tcp_echo/src/echo_protocol.erl

@@ -8,8 +8,8 @@ start_link(ListenerPid, Socket, Transport, Opts) ->
 	{ok, Pid}.
 
 init(ListenerPid, Socket, Transport, _Opts = []) ->
-	ok = ranch:accept_ack(ListenerPid),
-	loop(Socket, Transport).
+	{ok, Socket1} = ranch:accept_ack(ListenerPid, Socket, Transport, infinity),
+	loop(Socket1, Transport).
 
 loop(Socket, Transport) ->
 	case Transport:recv(Socket, 0, 5000) of

guide/protocols.md

@@ -19,17 +19,18 @@ the call to `ranch:start_listener/6`. This callback must
 return `{ok, Pid}`, with `Pid` the pid of the new process.
 
 The newly started process can then freely initialize itself. However,
-it must call `ranch:accept_ack/1` before doing any socket operation.
+it must call `ranch:accept_ack/4` before doing any socket operation.
 This will ensure the connection process is the owner of the socket.
-It expects the listener's pid as argument.
+It expects the listener's pid as argument, as well as the socket and
+the transport.
 
 ``` erlang
-ok = ranch:accept_ack(ListenerPid).
+ok = ranch:accept_ack(ListenerPid, Socket, Transport, Timeout).
 ```
 
 If your protocol code requires specific socket options, you should
 set them while initializing your connection process and before
-starting `ranch:accept_ack/1`. You can use `Transport:setopts/2`
+starting `ranch:accept_ack/4`. You can use `Transport:setopts/2`
 for that purpose.
 
 Following is the complete protocol code for the example found
@@ -47,8 +48,8 @@ start_link(ListenerPid, Socket, Transport, Opts) ->
     {ok, Pid}.
 
 init(ListenerPid, Socket, Transport, _Opts = []) ->
-    ok = ranch:accept_ack(ListenerPid),
-    loop(Socket, Transport).
+    {ok, Socket1} = ranch:accept_ack(ListenerPid, Socket, Transport, infinity),
+    loop(Socket1, Transport).
 
 loop(Socket, Transport) ->
     case Transport:recv(Socket, 0, 5000) of
@@ -66,7 +67,7 @@ Using gen_server
 Special processes like the ones that use the `gen_server` or `gen_fsm`
 behaviours have the particularity of having their `start_link` call not
 return until the `init` function returns. This is problematic, because
-you won't be able to call `ranch:accept_ack/1` from the `init` callback
+you won't be able to call `ranch:accept_ack/4` from the `init` callback
 as this would cause a deadlock to happen.
 
 There are two ways of solving this problem.
@@ -92,9 +93,9 @@ start_link(ListenerPid, Socket, Transport, Opts) ->
 init(ListenerPid, Socket, Transport, _Opts = []) ->
     ok = proc_lib:init_ack({ok, self()}),
     %% Perform any required state initialization here.
-    ok = ranch:accept_ack(ListenerPid),
+    {ok, Socket1} = ranch:accept_ack(ListenerPid, Socket, Transport, infinity),
     ok = Transport:setopts(Socket, [{active, once}]),
-    gen_server:enter_loop(?MODULE, [], {state, Socket, Transport}).
+    gen_server:enter_loop(?MODULE, [], {state, Socket1, Transport}).
 
 %% Other gen_server callbacks here.
 ```
@@ -114,8 +115,8 @@ init([ListenerPid, Socket, Transport]) ->
     {ok, {state, ListenerPid, Socket, Transport}, 0}.
 
 handle_info(timeout, State={state, ListenerPid, Socket, Transport}) ->
-    ok = ranch:accept_ack(ListenerPid),
-    ok = Transport:setopts(Socket, [{active, once}]),
-    {noreply, State};
+    {ok, Socket1} = ranch:accept_ack(ListenerPid, Socket, Transport, infinity),
+    ok = Transport:setopts(Socket1, [{active, once}]),
+    {noreply, {state, ListenerPid, Socket1, Transport}};
 %% ...
 ```

src/ranch.erl

@@ -18,7 +18,7 @@
 -export([start_listener/6]).
 -export([stop_listener/1]).
 -export([child_spec/6]).
--export([accept_ack/1]).
+-export([accept_ack/4]).
 -export([get_port/1]).
 -export([get_max_connections/1]).
 -export([set_max_connections/2]).
@@ -115,9 +115,10 @@ child_spec(Ref, NbAcceptors, Transport, TransOpts, Protocol, ProtoOpts)
 %%
 %% Effectively used to make sure the socket control has been given to
 %% the protocol process before starting to use it.
--spec accept_ack(pid()) -> ok.
-accept_ack(ListenerPid) ->
-	receive {shoot, ListenerPid} -> ok end.
+-spec accept_ack(pid(), any(), module(), timeout()) -> {ok, inet:socket()} | {error, closed | timeout | atom()}.
+accept_ack(ListenerPid, Socket, Transport, Timeout) ->
+	receive {shoot, ListenerPid} -> ok end,
+	Transport:handshake(Socket, Timeout).
 
 %% @doc Return the listener's port.
 -spec get_port(any()) -> inet:port_number().

src/ranch_ssl.erl

@@ -29,6 +29,7 @@
 -export([messages/0]).
 -export([listen/1]).
 -export([accept/2]).
+-export([handshake/2]).
 -export([connect/3]).
 -export([recv/3]).
 -export([send/2]).
@@ -110,21 +111,29 @@ listen(Opts) ->
 		[binary, {active, false}, {packet, raw},
 			{reuseaddr, true}, {nodelay, true}])).
 
-%% @doc Accept connections with the given listening socket.
+%% @doc Accept transport connections with the given listening socket.
 %%
-%% Note that this function does both the transport accept and
-%% the SSL handshake. The returned socket is thus fully connected.
+%% Note that this function only does the transport accept and
+%% the returned socket is only connected at the transport layer.
 %%
+%% @see handshake/2
 %% @see ssl:transport_accept/2
-%% @see ssl:ssl_accept/2
 -spec accept(ssl:sslsocket(), timeout())
 	-> {ok, ssl:sslsocket()} | {error, closed | timeout | atom() | tuple()}.
 accept(LSocket, Timeout) ->
-	case ssl:transport_accept(LSocket, Timeout) of
-		{ok, CSocket} ->
-			ssl_accept(CSocket, Timeout);
+	ssl:transport_accept(LSocket, Timeout).
+
+%% @doc Initiate the ssl handshake for the connected socket
+%%
+%% @see ssl:ssl_accept/2
+-spec handshake(ssl:sslsocket(), timeout())
+	-> {ok, ssl:sslsocket()} | {error, closed | timeout | atom() | tuple()}.
+handshake(Socket, Timeout) ->
+	case ssl:ssl_accept(Socket, Timeout) of
+		ok ->
+			{ok, Socket};
 		{error, Reason} ->
-			{error, Reason}
+			{error, {ssl_accept, Reason}}
 	end.
 
 %% @private Experimental. Open a connection to the given host and port number.
@@ -215,15 +224,3 @@ sockname(Socket) ->
 -spec close(ssl:sslsocket()) -> ok.
 close(Socket) ->
 	ssl:close(Socket).
-
-%% Internal.
-
--spec ssl_accept(ssl:sslsocket(), timeout())
-	-> {ok, ssl:sslsocket()} | {error, {ssl_accept, atom()}}.
-ssl_accept(Socket, Timeout) ->
-	case ssl:ssl_accept(Socket, Timeout) of
-		ok ->
-			{ok, Socket};
-		{error, Reason} ->
-			{error, {ssl_accept, Reason}}
-	end.

src/ranch_tcp.erl

@@ -24,6 +24,7 @@
 -export([messages/0]).
 -export([listen/1]).
 -export([accept/2]).
+-export([handshake/2]).
 -export([connect/3]).
 -export([recv/3]).
 -export([send/2]).
@@ -81,6 +82,12 @@ listen(Opts) ->
 accept(LSocket, Timeout) ->
 	gen_tcp:accept(LSocket, Timeout).
 
+%% @doc Post-accept handshake for the connected socket.
+-spec handshake(inet:socket(), timeout())
+	-> {ok, inet:socket()} | {error, closed | timeout | atom()}.
+handshake(Socket, _Timeout) ->
+	{ok, Socket}.
+
 %% @private Experimental. Open a connection to the given host and port number.
 %% @see gen_tcp:connect/3
 %% @todo Probably filter Opts?

src/ranch_transport.erl

@@ -44,6 +44,10 @@
 -callback accept(socket(), timeout())
 	-> {ok, socket()} | {error, closed | timeout | atom() | tuple()}.
 
+%% Initiate any post-accept handshake operations
+-callback handshake(socket(), timeout())
+	-> {ok, socket()} | {error, closed | timeout | atom() | tuple()}.
+
 %% Experimental. Open a connection to the given host and port number.
 -callback connect(string(), inet:port_number(), opts())
 	-> {ok, socket()} | {error, atom()}.

test/active_echo_protocol.erl

@@ -9,8 +9,8 @@ start_link(ListenerPid, Socket, Transport, Opts) ->
 	{ok, Pid}.
 
 init(ListenerPid, Socket, Transport, _Opts = []) ->
-	ok = ranch:accept_ack(ListenerPid),
-	loop(Socket, Transport).
+	{ok, Socket1} = ranch:accept_ack(ListenerPid, Socket, Transport, infinity),
+	loop(Socket1, Transport).
 
 loop(Socket, Transport) ->
 	{OK, Closed, Error} = Transport:messages(),

test/echo_protocol.erl

@@ -9,8 +9,8 @@ start_link(ListenerPid, Socket, Transport, Opts) ->
 	{ok, Pid}.
 
 init(ListenerPid, Socket, Transport, _Opts = []) ->
-	ok = ranch:accept_ack(ListenerPid),
-	loop(Socket, Transport).
+	{ok, Socket1} = ranch:accept_ack(ListenerPid, Socket, Transport, infinity),
+	loop(Socket1, Transport).
 
 loop(Socket, Transport) ->
 	case Transport:recv(Socket, 0, 5000) of

test/remove_conn_and_wait_protocol.erl

@@ -2,14 +2,14 @@
 -behaviour(ranch_protocol).
 
 -export([start_link/4]).
--export([init/2]).
+-export([init/4]).
 
-start_link(ListenerPid, _, _, [{remove, MaybeRemove}]) ->
-	Pid = spawn_link(?MODULE, init, [ListenerPid, MaybeRemove]),
+start_link(ListenerPid, Socket, Transport, [{remove, MaybeRemove}]) ->
+	Pid = spawn_link(?MODULE, init, [ListenerPid, Socket, Transport, MaybeRemove]),
 	{ok, Pid}.
 
-init(ListenerPid, MaybeRemove) ->
-	ranch:accept_ack(ListenerPid),
+init(ListenerPid, Socket, Transport, MaybeRemove) ->
+	_ = ranch:accept_ack(ListenerPid, Socket, Transport, infinity),
 	case MaybeRemove of
 		true ->
 			ranch_listener:remove_connection(ListenerPid);