Introduce resolve/2 and connect_options/3 callbacks for xmpp_stream_out

src/xmpp_stream_out.erl

@@ -90,9 +90,11 @@
 -callback tls_required(state()) -> boolean().
 -callback tls_verify(state()) -> boolean().
 -callback tls_enabled(state()) -> boolean().
+-callback resolve(string(), state()) -> [host_port()].
 -callback dns_timeout(state()) -> timeout().
 -callback dns_retries(state()) -> non_neg_integer().
 -callback default_port(state()) -> inet:port_number().
+-callback connect_options(inet:ip_address(), list(), state()) -> list().
 -callback address_families(state()) -> [inet:address_family()].
 -callback connect_timeout(state()) -> timeout().
 
@@ -121,9 +123,11 @@
 		     tls_required/1,
 		     tls_verify/1,
 		     tls_enabled/1,
+		     resolve/2,
 		     dns_timeout/1,
 		     dns_retries/1,
 		     default_port/1,
+		     connect_options/3,
 		     address_families/1,
 		     connect_timeout/1]).
 
@@ -394,8 +398,7 @@ handle_info({'$gen_event', {xmlstreamelement, El}},
 		  false -> process_invalid_xml(State1, El, Why)
 	      end
       end);
-handle_info({'$gen_all_state_event', {xmlstreamcdata, Data}},
-	    State) ->
+handle_info({'$gen_all_state_event', {xmlstreamcdata, Data}}, State) ->
     noreply(try callback(handle_cdata, Data, State)
 	    catch _:{?MODULE, undef} -> State
 	    end);
@@ -934,6 +937,17 @@ idna_to_ascii(Host) ->
 
 -spec resolve(string(), state()) -> {ok, [ip_port()]} | network_error().
 resolve(Host, State) ->
+    try callback(resolve, Host, State) of
+	[] ->
+	    do_resolve(Host, State);
+	HostPorts ->
+	    a_lookup(HostPorts, State)
+    catch _:{?MODULE, undef} ->
+	    do_resolve(Host, State)
+    end.
+
+-spec do_resolve(string(), state()) -> {ok, [ip_port()]} | network_error().
+do_resolve(Host, State) ->
     case srv_lookup(Host, State) of
 	{error, _Reason} ->
 	    DefaultPort = get_default_port(State),
@@ -967,10 +981,14 @@ srv_lookup(Host, State) ->
 	    end
     end.
 
-srv_lookup(Host, State, Timeout, Retries) ->
+srv_lookup(Host, #{xmlns := NS} = State, Timeout, Retries) ->
+    SRVType = case NS of
+		  ?NS_SERVER -> "-server._tcp.";
+		  ?NS_CLIENT -> "-client._tcp."
+	      end,
     TLSAddrs = case is_starttls_available(State) of
 		   true ->
-		       case srv_lookup("_xmpps-server._tcp." ++ Host,
+		       case srv_lookup("_xmpps" ++ SRVType ++ Host,
 				       Timeout, Retries) of
 			   {ok, HostEnt} ->
 			       [{A, true} || A <- HostEnt#hostent.h_addr_list];
@@ -980,7 +998,7 @@ srv_lookup(Host, State, Timeout, Retries) ->
 		   false ->
 		       []
 	       end,
-    case srv_lookup("_xmpp-server._tcp." ++ Host, Timeout, Retries) of
+    case srv_lookup("_xmpp" ++ SRVType ++ Host, Timeout, Retries) of
 	{ok, HostEntry} ->
 	    Addrs = [{A, false} || A <- HostEntry#hostent.h_addr_list],
 	    {ok, TLSAddrs ++ Addrs};
@@ -1033,24 +1051,35 @@ a_lookup([], _State, Acc, _) ->
 a_lookup(_Host, _Port, _TLS, _Family, _Timeout, Retries) when Retries < 1 ->
     {error, timeout};
 a_lookup(Host, Port, TLS, Family, Timeout, Retries) ->
-    Start = p1_time_compat:monotonic_time(milli_seconds),
-    case inet:gethostbyname(Host, Family, Timeout) of
-	{error, nxdomain} = Err ->
-	    %% inet:gethostbyname/3 doesn't return {error, timeout},
-	    %% so we should check if 'nxdomain' is in fact a result
-	    %% of a timeout.
-	    %% We also cannot use inet_res:gethostbyname/3 because
-	    %% it ignores DNS configuration settings (/etc/hosts, etc)
-	    End = p1_time_compat:monotonic_time(milli_seconds),
-	    if (End - Start) >= Timeout ->
-		    a_lookup(Host, Port, TLS, Family, Timeout, Retries - 1);
+    case inet:parse_address(Host) of
+	{ok, Addr} ->
+	    if tuple_size(Addr) == 4 andalso Family == inet ->
+		    {ok, [{Addr, Port, TLS}]};
+	       tuple_size(Addr) == 8 andalso Family == inet6 ->
+		    {ok, [{Addr, Port, TLS}]};
 	       true ->
-		    Err
+		    {error, nxdomain}
 	    end;
-	{error, _} = Err ->
-	    Err;
-	{ok, HostEntry} ->
-	    host_entry_to_addr_ports(HostEntry, Port, TLS)
+	{error, _} ->
+	    Start = p1_time_compat:monotonic_time(milli_seconds),
+	    case inet:gethostbyname(Host, Family, Timeout) of
+		{error, nxdomain} = Err ->
+		    %% inet:gethostbyname/3 doesn't return {error, timeout},
+		    %% so we should check if 'nxdomain' is in fact a result
+		    %% of a timeout.
+		    %% We also cannot use inet_res:gethostbyname/3 because
+		    %% it ignores DNS configuration settings (/etc/hosts, etc)
+		    End = p1_time_compat:monotonic_time(milli_seconds),
+		    if (End - Start) >= Timeout ->
+			    a_lookup(Host, Port, TLS, Family, Timeout, Retries - 1);
+		       true ->
+			    Err
+		    end;
+		{error, _} = Err ->
+		    Err;
+		{ok, HostEntry} ->
+		    host_entry_to_addr_ports(HostEntry, Port, TLS)
+	    end
     end.
 
 -spec h_addr_list_to_host_ports(h_addr_list()) -> {ok, [host_port()]} |
@@ -1094,7 +1123,7 @@ host_entry_to_addr_ports(#hostent{h_addr_list = AddrList}, Port, TLS) ->
 				       {error, {tls, tls_error_reason()}}.
 connect(AddrPorts, State) ->
     Timeout = get_connect_timeout(State),
-    case connect(AddrPorts, Timeout, {error, nxdomain}) of
+    case connect(AddrPorts, Timeout, State, {error, nxdomain}) of
 	{ok, Socket, {Addr, Port, TLS = true}} ->
 	    case starttls(Socket, State) of
 		{ok, TLSSocket} -> {ok, TLSSocket, {Addr, Port, TLS}};
@@ -1106,24 +1135,26 @@ connect(AddrPorts, State) ->
 	    {error, {socket, Why}}
     end.
 
--spec connect([ip_port()], timeout(), network_error()) ->
+-spec connect([ip_port()], timeout(), state(), network_error()) ->
 		     {ok, term(), ip_port()} | network_error().
-connect([{Addr, Port, TLS}|AddrPorts], Timeout, _) ->
+connect([{Addr, Port, TLS}|AddrPorts], Timeout, State, _) ->
     Type = get_addr_type(Addr),
-    try xmpp_socket:connect(Addr, Port,
-			    [binary, {packet, 0},
-			     {send_timeout, ?TCP_SEND_TIMEOUT},
-			     {send_timeout_close, true},
-			     {active, false}, Type],
-			    Timeout) of
+    Opts = [binary, {packet, 0},
+	    {send_timeout, ?TCP_SEND_TIMEOUT},
+	    {send_timeout_close, true},
+	    {active, false}, Type],
+    Opts1 = try callback(connect_options, Addr, Opts, State)
+	    catch _:{?MODULE, undef} -> Opts
+	    end,
+    try xmpp_socket:connect(Addr, Port, Opts1, Timeout) of
 	{ok, Socket} ->
 	    {ok, Socket, {Addr, Port, TLS}};
 	Err ->
-	    connect(AddrPorts, Timeout, Err)
+	    connect(AddrPorts, Timeout, State, Err)
     catch _:badarg ->
-	    connect(AddrPorts, Timeout, {error, einval})
+	    connect(AddrPorts, Timeout, State, {error, einval})
     end;
-connect([], _Timeout, Err) ->
+connect([], _Timeout, _State, Err) ->
     Err.
 
 -spec get_addr_type(inet:ip_address()) -> inet:address_family().