Add a test method, fix nil pointer panic

client/methods.go

@@ -8,6 +8,7 @@ import (
 	"net"
 	"net/url"
 	"strconv"
+	"strings"
 	"time"
 
 	syncthingprotocol "github.com/syncthing/protocol"
@@ -20,10 +21,10 @@ func GetInvitationFromRelay(uri *url.URL, id syncthingprotocol.DeviceID, certs [
 	}
 
 	conn, err := tls.Dial("tcp", uri.Host, configForCerts(certs))
-	conn.SetDeadline(time.Now().Add(10 * time.Second))
 	if err != nil {
 		return protocol.SessionInvitation{}, err
 	}
+	conn.SetDeadline(time.Now().Add(10 * time.Second))
 
 	if err := performHandshakeAndValidation(conn, uri); err != nil {
 		return protocol.SessionInvitation{}, err
@@ -97,6 +98,25 @@ func JoinSession(invitation protocol.SessionInvitation) (net.Conn, error) {
 	}
 }
 
+func TestRelay(uri *url.URL, certs []tls.Certificate) bool {
+	id := syncthingprotocol.NewDeviceID(certs[0].Certificate[0])
+	c := NewProtocolClient(uri, certs, nil)
+	go c.Serve()
+	defer c.Stop()
+
+	for i := 0; i < 5; i++ {
+		_, err := GetInvitationFromRelay(uri, id, certs)
+		if err == nil {
+			return true
+		}
+		if !strings.Contains(err.Error(), "Incorrect response code") {
+			return false
+		}
+		time.Sleep(time.Second)
+	}
+	return false
+}
+
 func configForCerts(certs []tls.Certificate) *tls.Config {
 	return &tls.Config{
 		Certificates:           certs,

testutil/main.go

@@ -23,10 +23,11 @@ func main() {
 	log.SetFlags(log.LstdFlags | log.Lshortfile)
 
 	var connect, relay, dir string
-	var join bool
+	var join, test bool
 
 	flag.StringVar(&connect, "connect", "", "Device ID to which to connect to")
 	flag.BoolVar(&join, "join", false, "Join relay")
+	flag.BoolVar(&test, "test", false, "Generic relay test")
 	flag.StringVar(&relay, "relay", "relay://127.0.0.1:22067", "Relay address")
 	flag.StringVar(&dir, "keys", ".", "Directory where cert.pem and key.pem is stored")
 
@@ -99,6 +100,12 @@ func main() {
 		log.Println("Joined", conn.RemoteAddr(), conn.LocalAddr())
 		connectToStdio(stdin, conn)
 		log.Println("Finished", conn.RemoteAddr(), conn.LocalAddr())
+	} else if test {
+		if client.TestRelay(uri, []tls.Certificate{cert}) {
+			log.Println("OK")
+		} else {
+			log.Println("FAIL")
+		}
 	} else {
 		log.Fatal("Requires either join or connect")
 	}