Fix Docker instructions and add option to bind both UDP and TCP DNS listeners (#130)

Dockerfile

@@ -19,3 +19,4 @@ RUN apk --no-cache add ca-certificates && update-ca-certificates
 VOLUME ["/etc/acme-dns", "/var/lib/acme-dns"]
 ENTRYPOINT ["./acme-dns"]
 EXPOSE 53 80 443
+EXPOSE 53/udp

README.md

@@ -149,6 +149,7 @@ See the INSTALL section for information on how to do this.
 ```
 docker run --rm --name acmedns                 \
  -p 53:53                                      \
+ -p 53:53/udp                                  \
  -p 80:80                                      \
  -v /path/to/your/config:/etc/acme-dns:ro      \
  -v /path/to/your/data:/var/lib/acme-dns       \
@@ -216,8 +217,8 @@ $ dig @auth.example.org d420c923-bbd7-4056-ab64-c3ca54c9b3cf.auth.example.org
 # In this case acme-dns will error out and you will need to define the listening interface
 # for example: listen = "127.0.0.1:53"
 listen = ":53"
-# protocol, "udp", "udp4", "udp6" or "tcp", "tcp4", "tcp6"
-protocol = "udp"
+# protocol, "both", "both4", "both6", "udp", "udp4", "udp6" or "tcp", "tcp4", "tcp6"
+protocol = "both"
 # domain name to serve the requests off of
 domain = "auth.example.org"
 # zone name server
@@ -300,6 +301,10 @@ logformat = "text"
 
 
 ## Changelog
+
+- master
+   - Changed
+      - A new protocol selection for DNS server "both", that binds both - UDP and TCP ports.
 - v0.6
    - New
       - Command line flag `-c` to specify location of config file.

config.cfg

@@ -2,9 +2,9 @@
 # DNS interface. Note that systemd-resolved may reserve port 53 on 127.0.0.53
 # In this case acme-dns will error out and you will need to define the listening interface
 # for example: listen = "127.0.0.1:53"
-listen = ":53"
-# protocol, "udp", "udp4", "udp6" or "tcp", "tcp4", "tcp6"
-protocol = "udp"
+listen = "127.0.0.1:53"
+# protocol, "both", "both4", "both6", "udp", "udp4", "udp6" or "tcp", "tcp4", "tcp6"
+protocol = "both"
 # domain name to serve the requests off of
 domain = "auth.example.org"
 # zone name server
@@ -26,7 +26,8 @@ debug = false
 engine = "sqlite3"
 # Connection string, filename for sqlite3 and postgres://$username:$password@$host/$db_name for postgres
 # Please note that the default Docker image uses path /var/lib/acme-dns/acme-dns.db for sqlite3
-connection = "/var/lib/acme-dns/acme-dns.db"
+#connection = "/var/lib/acme-dns/acme-dns.db"
+connection = "acme-dns.db"
 # connection = "postgres://user:password@localhost/acmedns_db"
 
 [api]

docker-compose.yml

@@ -8,6 +8,7 @@ services:
     ports:
       - "443:443"
       - "53:53"
+      - "53:53/udp"
       - "80:80"
     volumes:
       - ./config:/etc/acme-dns:ro

main.go

@@ -8,6 +8,7 @@ import (
 	stdlog "log"
 	"net/http"
 	"os"
+	"strings"
 	"syscall"
 
 	"github.com/julienschmidt/httprouter"
@@ -60,8 +61,25 @@ func main() {
 	errChan := make(chan error, 1)
 
 	// DNS server
-	dnsServer := setupDNSServer()
+	if strings.HasPrefix(Config.General.Proto, "both") {
+		// Handle the case where DNS server should be started for both udp and tcp
+		udpProto := "udp"
+		tcpProto := "tcp"
+		if strings.HasSuffix(Config.General.Proto, "4") {
+			udpProto += "4"
+			tcpProto += "4"
+		} else if strings.HasSuffix(Config.General.Proto, "6") {
+			udpProto += "6"
+			tcpProto += "6"
+		}
+		dnsServerUDP := setupDNSServer(udpProto)
+		dnsServerTCP := setupDNSServer(tcpProto)
+		go startDNS(dnsServerUDP, errChan)
+		go startDNS(dnsServerTCP, errChan)
+	} else {
+		dnsServer := setupDNSServer(Config.General.Proto)
 		go startDNS(dnsServer, errChan)
+	}
 
 	// HTTP API
 	go startHTTPAPI(errChan)
@@ -79,15 +97,15 @@ func main() {
 func startDNS(server *dns.Server, errChan chan error) {
 	// DNS server part
 	dns.HandleFunc(".", handleRequest)
-	log.WithFields(log.Fields{"addr": Config.General.Listen}).Info("Listening DNS")
+	log.WithFields(log.Fields{"addr": Config.General.Listen, "proto": server.Net}).Info("Listening DNS")
 	err := server.ListenAndServe()
 	if err != nil {
 		errChan <- err
 	}
 }
 
-func setupDNSServer() *dns.Server {
-	return &dns.Server{Addr: Config.General.Listen, Net: Config.General.Proto}
+func setupDNSServer(proto string) *dns.Server {
+	return &dns.Server{Addr: Config.General.Listen, Net: proto}
 }
 
 func startHTTPAPI(errChan chan error) {

main_test.go

@@ -43,7 +43,7 @@ func TestMain(m *testing.M) {
 		_ = newDb.Init("sqlite3", ":memory:")
 	}
 	DB = newDb
-	server := setupDNSServer()
+	server := setupDNSServer("udp")
 	// Make sure that we're not creating a race condition in tests
 	var wg sync.WaitGroup
 	wg.Add(1)