Release 2.1.0

According to Apple: Swift compiler no longer supports statically linking the Swift libraries. They're included in the OS by default starting with macOS Mojave 10.14.4. For macOS Mojave 10.14.3 and earlier, there's an optional Swift library package that can be downloaded from "More Downloads" for Apple Developers at https://developer.apple.com/download/more/

Changelog.md

@@ -4,6 +4,13 @@ This Changelog records major changes between versions.
 
 Not all changes are recorded. Please check git log for details.
 
+## Version 2.1.0
+
+- Add `local_addr` configuration for doh-server (#39)
+- Fix a problem when compiling on macOS 10.14.4 or newer
+- Add Quad9 DoH server to the example `doh-client.conf`
+- Use TCP when appropriate for the given query type/response (AXFR/IXFR)
+
 ## Version 2.0.1
 
 - Fix a crash with the random load balancing algorithm.

darwin-wrapper/Makefile

@@ -6,7 +6,7 @@ PREFIX = /usr/local
 all: doh-logger
 
 doh-logger: doh-logger.swift
-	$(SWIFTC) -o $@ -O -static-stdlib $<
+	$(SWIFTC) -o $@ -O $<
 
 clean:
 	rm -f doh-logger

doh-client/doh-client.conf

@@ -21,25 +21,24 @@ upstream_selector = "random"
 #    weight = 50
 
 ## CloudFlare's resolver, bad ECS, good DNSSEC
-#[[upstream.upstream_google]]
-#    url = "https://cloudflare-dns.com/dns-query"
-#    weight = 50
-
-## CloudFlare's resolver, bad ECS, good DNSSEC
-#[[upstream.upstream_google]]
-#    url = "https://1.1.1.1/dns-query"
-#    weight = 50
-
-# CloudFlare's resolver, bad ECS, good DNSSEC
+## ECS is disabled for privacy by design: https://developers.cloudflare.com/1.1.1.1/nitty-gritty-details/#edns-client-subnet
 [[upstream.upstream_ietf]]
     url = "https://cloudflare-dns.com/dns-query"
     weight = 50
 
 ## CloudFlare's resolver, bad ECS, good DNSSEC
+## ECS is disabled for privacy by design: https://developers.cloudflare.com/1.1.1.1/nitty-gritty-details/#edns-client-subnet
+## Note that some ISPs have problems connecting to 1.1.1.1, try 1.0.0.1 if problems happen.
 #[[upstream.upstream_ietf]]
 #    url = "https://1.1.1.1/dns-query"
 #    weight = 50
 
+## Quad9's resolver, bad ECS, good DNSSEC
+## ECS is disabled for privacy by design: https://www.quad9.net/faq/#What_is_EDNS_Client-Subnet
+#[[upstream.upstream_ietf]]
+#    url = "https://9.9.9.9/dns-query"
+#    weight = 50
+
 ## Google's experimental resolver, good ECS, good DNSSEC
 #[[upstream.upstream_ietf]]
 #    url = "https://dns.google.com/experimental"

doh-client/version.go

@@ -24,6 +24,6 @@
 package main
 
 const (
-	VERSION    = "2.0.1"
+	VERSION    = "2.1.0"
 	USER_AGENT = "DNS-over-HTTPS/" + VERSION + " (+https://github.com/m13253/dns-over-https)"
 )

doh-server/config.go

@@ -31,6 +31,7 @@ import (
 
 type config struct {
 	Listen           []string `toml:"listen"`
+	LocalAddr        string   `toml:"local_addr"`
 	Cert             string   `toml:"cert"`
 	Key              string   `toml:"key"`
 	Path             string   `toml:"path"`

doh-server/doh-server.conf

@@ -4,6 +4,10 @@ listen = [
     "[::1]:8053",
 ]
 
+# Local address and port for upstream DNS
+# If left empty, a local address is automatically chosen.
+local_addr = ""
+
 # TLS certification file
 # If left empty, plain-text HTTP will be used.
 # You are recommended to leave empty and to use a server load balancer (e.g.

doh-server/main.go

@@ -110,6 +110,9 @@ func main() {
 		conf.Verbose = true
 	}
 
-	server := NewServer(conf)
+	server, err := NewServer(conf)
+	if err != nil {
+		log.Fatalln(err)
+	}
 	_ = server.Start()
 }

doh-server/server.go

@@ -56,22 +56,41 @@ type DNSRequest struct {
 	errtext         string
 }
 
-func NewServer(conf *config) (s *Server) {
-	s = &Server{
+func NewServer(conf *config) (*Server, error) {
+	timeout := time.Duration(conf.Timeout) * time.Second
+	s := &Server{
 		conf: conf,
 		udpClient: &dns.Client{
 			Net:     "udp",
 			UDPSize: dns.DefaultMsgSize,
-			Timeout: time.Duration(conf.Timeout) * time.Second,
+			Timeout: timeout,
 		},
 		tcpClient: &dns.Client{
 			Net:     "tcp",
-			Timeout: time.Duration(conf.Timeout) * time.Second,
+			Timeout: timeout,
 		},
 		servemux: http.NewServeMux(),
 	}
+	if conf.LocalAddr != "" {
+		udpLocalAddr, err := net.ResolveUDPAddr("udp", conf.LocalAddr)
+		if err != nil {
+			return nil, err
+		}
+		tcpLocalAddr, err := net.ResolveTCPAddr("tcp", conf.LocalAddr)
+		if err != nil {
+			return nil, err
+		}
+		s.udpClient.Dialer = &net.Dialer{
+			Timeout:   timeout,
+			LocalAddr: udpLocalAddr,
+		}
+		s.tcpClient.Dialer = &net.Dialer{
+			Timeout:   timeout,
+			LocalAddr: tcpLocalAddr,
+		}
+	}
 	s.servemux.HandleFunc(conf.Path, s.handlerFunc)
-	return
+	return s, nil
 }
 
 func (s *Server) Start() error {
@@ -244,19 +263,38 @@ func (s *Server) patchRootRD(req *DNSRequest) *DNSRequest {
 	return req
 }
 
+// Return the position index for the question of qtype from a DNS msg, otherwise return -1
+func (s *Server) indexQuestionType(msg *dns.Msg, qtype uint16) int {
+	for i, question := range msg.Question {
+		if question.Qtype == qtype {
+			return i
+		}
+	}
+	return -1
+}
+
 func (s *Server) doDNSQuery(ctx context.Context, req *DNSRequest) (resp *DNSRequest, err error) {
 	// TODO(m13253): Make ctx work. Waiting for a patch for ExchangeContext from miekg/dns.
 	numServers := len(s.conf.Upstream)
 	for i := uint(0); i < s.conf.Tries; i++ {
 		req.currentUpstream = s.conf.Upstream[rand.Intn(numServers)]
-		if !s.conf.TCPOnly {
+
+		// Use TCP if always configured to or if the Query type dictates it (AXFR)
+		if s.conf.TCPOnly || (s.indexQuestionType(req.request, dns.TypeAXFR) > -1) {
+			req.response, _, err = s.tcpClient.Exchange(req.request, req.currentUpstream)
+		} else {
 			req.response, _, err = s.udpClient.Exchange(req.request, req.currentUpstream)
 			if err == nil && req.response != nil && req.response.Truncated {
 				log.Println(err)
 				req.response, _, err = s.tcpClient.Exchange(req.request, req.currentUpstream)
 			}
-		} else {
-			req.response, _, err = s.tcpClient.Exchange(req.request, req.currentUpstream)
+
+			// Retry with TCP if this was an IXFR request and we only received an SOA
+			if (s.indexQuestionType(req.request, dns.TypeIXFR) > -1) &&
+				(len(req.response.Answer) == 1) &&
+				(req.response.Answer[0].Header().Rrtype == dns.TypeSOA) {
+				req.response, _, err = s.tcpClient.Exchange(req.request, req.currentUpstream)
+			}
 		}
 		if err == nil {
 			return req, nil

doh-server/version.go

@@ -24,6 +24,6 @@
 package main
 
 const (
-	VERSION    = "2.0.1"
+	VERSION    = "2.1.0"
 	USER_AGENT = "DNS-over-HTTPS/" + VERSION + " (+https://github.com/m13253/dns-over-https)"
 )