Add DoH Config (#227)

x/config/config.go

@@ -38,6 +38,10 @@ func NewDefaultConfigParser() *ConfigParser {
 	p := new(ConfigParser)
 
 	// Please keep the list in alphabetical order.
+	p.RegisterStreamDialerWrapper("doh", wrapStreamDialerWithDOH)
+	p.RegisterPacketDialerWrapper("doh", func(baseDialer transport.PacketDialer, wrapConfig *url.URL) (transport.PacketDialer, error) {
+		return nil, errors.New("doh is not supported for PacketDialers")
+	})
 
 	p.RegisterStreamDialerWrapper("override", wrapStreamDialerWithOverride)
 	p.RegisterPacketDialerWrapper("override", wrapPacketDialerWithOverride)

x/config/dns.go

@@ -0,0 +1,66 @@
+// Copyright 2024 Jigsaw Operations LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package config
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"net/url"
+	"strings"
+
+	"github.com/Jigsaw-Code/outline-sdk/dns"
+	"github.com/Jigsaw-Code/outline-sdk/transport"
+)
+
+func wrapStreamDialerWithDOH(innerDialer transport.StreamDialer, configURL *url.URL) (transport.StreamDialer, error) {
+	query := configURL.Opaque
+	values, err := url.ParseQuery(query)
+	if err != nil {
+		return nil, err
+	}
+	var name, address string
+	for key, values := range values {
+		switch strings.ToLower(key) {
+		case "address":
+			if len(values) != 1 {
+				return nil, fmt.Errorf("address option must has one value, found %v", len(values))
+			}
+			address = values[0]
+		case "name":
+			if len(values) != 1 {
+				return nil, fmt.Errorf("name option must has one value, found %v", len(values))
+			}
+			name = values[0]
+		default:
+			return nil, fmt.Errorf("unsupported option %v", key)
+
+		}
+	}
+	if name == "" {
+		return nil, errors.New("must set a name")
+	}
+	if address == "" {
+		address = name
+	}
+	_, port, err := net.SplitHostPort(address)
+	if err != nil {
+		address = net.JoinHostPort(address, "443")
+		port = "443"
+	}
+	dohURL := url.URL{Scheme: "https", Host: net.JoinHostPort(name, port), Path: "/dns-query"}
+	resolver := dns.NewHTTPSResolver(innerDialer, address, dohURL.String())
+	return dns.NewStreamDialer(resolver, innerDialer)
+}

x/config/doc.go

@@ -44,6 +44,14 @@ SOCKS5 proxy (currently streams only, package [github.com/Jigsaw-Code/outline-sd
 
 USERINFO field is optional and only required if username and password authentication is used. It is in the format of username:password.
 
+DNS-over-HTTPS resolution (streams only, package [github.com/Jigsaw-Code/outline-sdk/dns])
+
+It takes a host name and a host:port address. The name will be used in the SNI and Host header, while the address is used to connect
+to the DoH server. The address is optional, and will default to "[NAME]:443". The resulting dialer will use the input dialer with
+Happy Eyeballs to connect to the destination.
+
+	doh:name=[NAME]&address=[ADDRESS]
+
 Stream split transport (streams only, package [github.com/Jigsaw-Code/outline-sdk/transport/split])
 
 It takes the length of the prefix. The stream will be split when PREFIX_LENGTH bytes are first written.

x/examples/fetch/main.go

@@ -45,6 +45,7 @@ func main() {
 	transportFlag := flag.String("transport", "", "Transport config")
 	addressFlag := flag.String("address", "", "Address to connect to. If empty, use the URL authority")
 	methodFlag := flag.String("method", "GET", "The HTTP method to use")
+	timeoutSecFlag := flag.Int("timeout", 5, "Timeout in seconds")
 
 	flag.Parse()
 
@@ -89,7 +90,7 @@ func main() {
 		}
 		return dialer.DialStream(ctx, net.JoinHostPort(host, port))
 	}
-	httpClient := &http.Client{Transport: &http.Transport{DialContext: dialContext}, Timeout: 5 * time.Second}
+	httpClient := &http.Client{Transport: &http.Transport{DialContext: dialContext}, Timeout: time.Duration(*timeoutSecFlag) * time.Second}
 
 	req, err := http.NewRequest(*methodFlag, url, nil)
 	if err != nil {