Use the inet:socket() type instead of the user-defined one.

include/http.hrl

@@ -14,7 +14,7 @@
 
 -record(http_req, {
 	%% Transport.
-	socket     = undefined :: undefined | socket(),
+	socket     = undefined :: undefined | inet:socket(),
 	transport  = undefined :: undefined | module(),
 	connection = keepalive :: keepalive | close,
 

include/types.hrl

@@ -16,7 +16,6 @@
 	{takeover, Node::node()} | {failover, Node::node()}.
 
 -type posix() :: atom().
--opaque socket() :: term().
 -opaque sslsocket() :: term().
 -type port_number() :: 0..65535.
 

src/cowboy_acceptor.erl

@@ -20,7 +20,7 @@
 
 %% API.
 
--spec start_link(LSocket::socket(), Transport::module(),
+-spec start_link(LSocket::inet:socket(), Transport::module(),
 	Protocol::module(), Opts::term(), ReqsSup::pid()) -> {ok, Pid::pid()}.
 start_link(LSocket, Transport, Protocol, Opts, ReqsSup) ->
 	Pid = spawn_link(?MODULE, acceptor,
@@ -29,7 +29,7 @@ start_link(LSocket, Transport, Protocol, Opts, ReqsSup) ->
 
 %% Internal.
 
--spec acceptor(LSocket::socket(), Transport::module(),
+-spec acceptor(LSocket::inet:socket(), Transport::module(),
 	Protocol::module(), Opts::term(), ReqsSup::pid()) -> no_return().
 acceptor(LSocket, Transport, Protocol, Opts, ReqsSup) ->
 	case Transport:accept(LSocket, 2000) of

src/cowboy_http_protocol.erl

@@ -20,7 +20,7 @@
 -include("include/http.hrl").
 
 -record(state, {
-	socket :: socket(),
+	socket :: inet:socket(),
 	transport :: module(),
 	dispatch :: dispatch(),
 	handler :: {Handler::module(), Opts::term()},
@@ -32,15 +32,15 @@
 
 %% API.
 
--spec start_link(Socket::socket(), Transport::module(), Opts::term())
+-spec start_link(Socket::inet:socket(), Transport::module(), Opts::term())
 	-> {ok, Pid::pid()}.
 start_link(Socket, Transport, Opts) ->
 	Pid = spawn_link(?MODULE, init, [Socket, Transport, Opts]),
 	{ok, Pid}.
 
 %% FSM.
 
--spec init(Socket::socket(), Transport::module(), Opts::term()) -> ok.
+-spec init(Socket::inet:socket(), Transport::module(), Opts::term()) -> ok.
 init(Socket, Transport, Opts) ->
 	Dispatch = proplists:get_value(dispatch, Opts, []),
 	MaxEmptyLines = proplists:get_value(max_empty_lines, Opts, 5),

src/cowboy_requests_sup.erl

@@ -26,7 +26,7 @@
 start_link() ->
 	supervisor:start_link(?MODULE, []).
 
--spec start_request(Socket::socket(), Transport::module(),
+-spec start_request(Socket::inet:socket(), Transport::module(),
 	Protocol::module(), Opts::term()) -> {ok, Pid::pid()}.
 start_request(Socket, Transport, Protocol, Opts) ->
 	Protocol:start_link(Socket, Transport, Opts).

src/cowboy_tcp_transport.erl

@@ -27,42 +27,43 @@ name() -> tcp.
 messages() -> {tcp, tcp_closed, tcp_error}.
 
 -spec listen([{port, Port::port_number()}])
-	-> {ok, LSocket::socket()} | {error, Reason::posix()}.
+	-> {ok, LSocket::inet:socket()} | {error, Reason::posix()}.
 listen(Opts) ->
 	{port, Port} = lists:keyfind(port, 1, Opts),
 	gen_tcp:listen(Port, [binary, {active, false},
 		{packet, raw}, {reuseaddr, true}]).
 
--spec accept(LSocket::socket(), Timeout::timeout())
-	-> {ok, Socket::socket()} | {error, Reason::closed | timeout | posix()}.
+-spec accept(LSocket::inet:socket(), Timeout::timeout())
+	-> {ok, Socket::inet:socket()}
+	| {error, Reason::closed | timeout | posix()}.
 accept(LSocket, Timeout) ->
 	gen_tcp:accept(LSocket, Timeout).
 
--spec recv(Socket::socket(), Length::integer(), Timeout::timeout())
+-spec recv(Socket::inet:socket(), Length::integer(), Timeout::timeout())
 	-> {ok, Packet::term()} | {error, Reason::closed | posix()}.
 recv(Socket, Length, Timeout) ->
 	gen_tcp:recv(Socket, Length, Timeout).
 
--spec send(Socket::socket(), Packet::iolist())
+-spec send(Socket::inet:socket(), Packet::iolist())
 	-> ok | {error, Reason::posix()}.
 send(Socket, Packet) ->
 	gen_tcp:send(Socket, Packet).
 
--spec setopts(Socket::socket(), Opts::list(term()))
+-spec setopts(Socket::inet:socket(), Opts::list(term()))
 	-> ok | {error, Reason::posix()}.
 setopts(Socket, Opts) ->
 	inet:setopts(Socket, Opts).
 
--spec controlling_process(Socket::socket(), Pid::pid())
+-spec controlling_process(Socket::inet:socket(), Pid::pid())
 	-> ok | {error, Reason::closed | not_owner | posix()}.
 controlling_process(Socket, Pid) ->
 	gen_tcp:controlling_process(Socket, Pid).
 
--spec peername(Socket::socket())
+-spec peername(Socket::inet:socket())
 	-> {ok, {Address::inet:ip_address(), Port::port_number()}} | {error, posix()}.
 peername(Socket) ->
 	inet:peername(Socket).
 
--spec close(Socket::socket()) -> ok.
+-spec close(Socket::inet:socket()) -> ok.
 close(Socket) ->
 	gen_tcp:close(Socket).