Cleanup ParseHostOrFile (#2100)

Create plugin/pkg/transport that holds the transport related functions.
This needed to be a new pkg to prevent cyclic import errors.

This cleans up a bunch of duplicated code in core/dnsserver that also
tried to parse a transport (now all done in transport.Parse).

Signed-off-by: Miek Gieben <miek@miek.nl>

core/dnsserver/address.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 
 	"github.com/coredns/coredns/plugin"
+	"github.com/coredns/coredns/plugin/pkg/transport"
 
 	"github.com/miekg/dns"
 )
@@ -27,43 +28,13 @@ func (z zoneAddr) String() string {
 	return s
 }
 
-// Transport returns the protocol of the string s
-func Transport(s string) string {
-	switch {
-	case strings.HasPrefix(s, TransportTLS+"://"):
-		return TransportTLS
-	case strings.HasPrefix(s, TransportDNS+"://"):
-		return TransportDNS
-	case strings.HasPrefix(s, TransportGRPC+"://"):
-		return TransportGRPC
-	case strings.HasPrefix(s, TransportHTTPS+"://"):
-		return TransportHTTPS
-	}
-	return TransportDNS
-}
-
 // normalizeZone parses an zone string into a structured format with separate
 // host, and port portions, as well as the original input string.
 func normalizeZone(str string) (zoneAddr, error) {
 	var err error
 
-	// Default to DNS if there isn't a transport protocol prefix.
+	var trans string
-	trans := TransportDNS
+	trans, str = transport.Parse(str)
-
-	switch {
-	case strings.HasPrefix(str, TransportTLS+"://"):
-		trans = TransportTLS
-		str = str[len(TransportTLS+"://"):]
-	case strings.HasPrefix(str, TransportDNS+"://"):
-		trans = TransportDNS
-		str = str[len(TransportDNS+"://"):]
-	case strings.HasPrefix(str, TransportGRPC+"://"):
-		trans = TransportGRPC
-		str = str[len(TransportGRPC+"://"):]
-	case strings.HasPrefix(str, TransportHTTPS+"://"):
-		trans = TransportHTTPS
-		str = str[len(TransportHTTPS+"://"):]
-	}
 
 	host, port, ipnet, err := plugin.SplitHostPort(str)
 	if err != nil {
@@ -71,17 +42,15 @@ func normalizeZone(str string) (zoneAddr, error) {
 	}
 
 	if port == "" {
-		if trans == TransportDNS {
+		switch trans {
+		case transport.DNS:
 			port = Port
-		}
+		case transport.TLS:
-		if trans == TransportTLS {
+			port = transport.TLSPort
-			port = TLSPort
+		case transport.GRPC:
-		}
+			port = transport.GRPCPort
-		if trans == TransportGRPC {
+		case transport.HTTPS:
-			port = GRPCPort
+			port = transport.HTTPSPort
-		}
-		if trans == TransportHTTPS {
-			port = HTTPSPort
 		}
 	}
 
@@ -103,14 +72,6 @@ func SplitProtocolHostPort(address string) (protocol string, ip string, port str
 	}
 }
 
-// Supported transports.
-const (
-	TransportDNS   = "dns"
-	TransportTLS   = "tls"
-	TransportGRPC  = "grpc"
-	TransportHTTPS = "https"
-)
-
 type zoneOverlap struct {
 	registeredAddr map[zoneAddr]zoneAddr // each zoneAddr is registered once by its key
 	unboundOverlap map[zoneAddr]zoneAddr // the "no bind" equiv ZoneAdddr is registered by its original key

core/dnsserver/address_test.go

@@ -192,21 +192,3 @@ func TestOverlapAddressChecker(t *testing.T) {
 		}
 	}
 }
-
-func TestTransport(t *testing.T) {
-	for i, test := range []struct {
-		input    string
-		expected string
-	}{
-		{"dns://.:53", TransportDNS},
-		{"2003::1/64.:53", TransportDNS},
-		{"grpc://example.org:1443 ", TransportGRPC},
-		{"tls://example.org ", TransportTLS},
-		{"https://example.org ", TransportHTTPS},
-	} {
-		actual := Transport(test.input)
-		if actual != test.expected {
-			t.Errorf("Test %d: Expected %s but got %s", i, test.expected, actual)
-		}
-	}
-}

core/dnsserver/register.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/coredns/coredns/plugin"
 	"github.com/coredns/coredns/plugin/pkg/dnsutil"
+	"github.com/coredns/coredns/plugin/pkg/transport"
 
 	"github.com/mholt/caddy"
 	"github.com/mholt/caddy/caddyfile"
@@ -111,29 +112,29 @@ func (h *dnsContext) MakeServers() ([]caddy.Server, error) {
 	var servers []caddy.Server
 	for addr, group := range groups {
 		// switch on addr
-		switch Transport(addr) {
+		switch tr, _ := transport.Parse(addr); tr {
-		case TransportDNS:
+		case transport.DNS:
 			s, err := NewServer(addr, group)
 			if err != nil {
 				return nil, err
 			}
 			servers = append(servers, s)
 
-		case TransportTLS:
+		case transport.TLS:
 			s, err := NewServerTLS(addr, group)
 			if err != nil {
 				return nil, err
 			}
 			servers = append(servers, s)
 
-		case TransportGRPC:
+		case transport.GRPC:
 			s, err := NewServergRPC(addr, group)
 			if err != nil {
 				return nil, err
 			}
 			servers = append(servers, s)
 
-		case TransportHTTPS:
+		case transport.HTTPS:
 			s, err := NewServerHTTPS(addr, group)
 			if err != nil {
 				return nil, err
@@ -234,16 +235,8 @@ func groupConfigsByListenAddr(configs []*Config) (map[string][]*Config, error) {
 	return groups, nil
 }
 
-const (
+// DefaultPort is the default port.
-	// DefaultPort is the default port.
+const DefaultPort = "53"
-	DefaultPort = "53"
-	// TLSPort is the default port for DNS-over-TLS.
-	TLSPort = "853"
-	// GRPCPort is the default port for DNS-over-gRPC.
-	GRPCPort = "443"
-	// HTTPSPort is the default port for DNS-over-HTTPS.
-	HTTPSPort = "443"
-)
 
 // These "soft defaults" are configurable by
 // command line flags, etc.

core/dnsserver/server.go

@@ -15,6 +15,7 @@ import (
 	"github.com/coredns/coredns/plugin/pkg/log"
 	"github.com/coredns/coredns/plugin/pkg/rcode"
 	"github.com/coredns/coredns/plugin/pkg/trace"
+	"github.com/coredns/coredns/plugin/pkg/transport"
 	"github.com/coredns/coredns/request"
 
 	"github.com/miekg/dns"
@@ -134,7 +135,7 @@ func (s *Server) ServePacket(p net.PacketConn) error {
 
 // Listen implements caddy.TCPServer interface.
 func (s *Server) Listen() (net.Listener, error) {
-	l, err := net.Listen("tcp", s.Addr[len(TransportDNS+"://"):])
+	l, err := net.Listen("tcp", s.Addr[len(transport.DNS+"://"):])
 	if err != nil {
 		return nil, err
 	}
@@ -143,7 +144,7 @@ func (s *Server) Listen() (net.Listener, error) {
 
 // ListenPacket implements caddy.UDPServer interface.
 func (s *Server) ListenPacket() (net.PacketConn, error) {
-	p, err := net.ListenPacket("udp", s.Addr[len(TransportDNS+"://"):])
+	p, err := net.ListenPacket("udp", s.Addr[len(transport.DNS+"://"):])
 	if err != nil {
 		return nil, err
 	}

core/dnsserver/server_grpc.go

@@ -8,6 +8,7 @@ import (
 	"net"
 
 	"github.com/coredns/coredns/pb"
+	"github.com/coredns/coredns/plugin/pkg/transport"
 	"github.com/coredns/coredns/plugin/pkg/watch"
 
 	"github.com/grpc-ecosystem/grpc-opentracing/go/otgrpc"
@@ -73,7 +74,7 @@ func (s *ServergRPC) ServePacket(p net.PacketConn) error { return nil }
 // Listen implements caddy.TCPServer interface.
 func (s *ServergRPC) Listen() (net.Listener, error) {
 
-	l, err := net.Listen("tcp", s.Addr[len(TransportGRPC+"://"):])
+	l, err := net.Listen("tcp", s.Addr[len(transport.GRPC+"://"):])
 	if err != nil {
 		return nil, err
 	}
@@ -90,7 +91,7 @@ func (s *ServergRPC) OnStartupComplete() {
 		return
 	}
 
-	out := startUpZones(TransportGRPC+"://", s.Addr, s.zones)
+	out := startUpZones(transport.GRPC+"://", s.Addr, s.zones)
 	if out != "" {
 		fmt.Print(out)
 	}

core/dnsserver/server_https.go

@@ -12,6 +12,7 @@ import (
 	"github.com/coredns/coredns/plugin/pkg/dnsutil"
 	"github.com/coredns/coredns/plugin/pkg/doh"
 	"github.com/coredns/coredns/plugin/pkg/response"
+	"github.com/coredns/coredns/plugin/pkg/transport"
 )
 
 // ServerHTTPS represents an instance of a DNS-over-HTTPS server.
@@ -60,7 +61,7 @@ func (s *ServerHTTPS) ServePacket(p net.PacketConn) error { return nil }
 // Listen implements caddy.TCPServer interface.
 func (s *ServerHTTPS) Listen() (net.Listener, error) {
 
-	l, err := net.Listen("tcp", s.Addr[len(TransportHTTPS+"://"):])
+	l, err := net.Listen("tcp", s.Addr[len(transport.HTTPS+"://"):])
 	if err != nil {
 		return nil, err
 	}
@@ -77,7 +78,7 @@ func (s *ServerHTTPS) OnStartupComplete() {
 		return
 	}
 
-	out := startUpZones(TransportHTTPS+"://", s.Addr, s.zones)
+	out := startUpZones(transport.HTTPS+"://", s.Addr, s.zones)
 	if out != "" {
 		fmt.Print(out)
 	}

core/dnsserver/server_tls.go

@@ -6,6 +6,8 @@ import (
 	"fmt"
 	"net"
 
+	"github.com/coredns/coredns/plugin/pkg/transport"
+
 	"github.com/miekg/dns"
 )
 
@@ -55,7 +57,7 @@ func (s *ServerTLS) ServePacket(p net.PacketConn) error { return nil }
 
 // Listen implements caddy.TCPServer interface.
 func (s *ServerTLS) Listen() (net.Listener, error) {
-	l, err := net.Listen("tcp", s.Addr[len(TransportTLS+"://"):])
+	l, err := net.Listen("tcp", s.Addr[len(transport.TLS+"://"):])
 	if err != nil {
 		return nil, err
 	}
@@ -72,7 +74,7 @@ func (s *ServerTLS) OnStartupComplete() {
 		return
 	}
 
-	out := startUpZones(TransportTLS+"://", s.Addr, s.zones)
+	out := startUpZones(transport.TLS+"://", s.Addr, s.zones)
 	if out != "" {
 		fmt.Print(out)
 	}

plugin/forward/connect.go

@@ -35,16 +35,16 @@ func averageTimeout(currentAvg *int64, observedDuration time.Duration, weight in
 	atomic.AddInt64(currentAvg, int64(observedDuration-dt)/weight)
 }
 
-func (t *transport) dialTimeout() time.Duration {
+func (t *Transport) dialTimeout() time.Duration {
 	return limitTimeout(&t.avgDialTime, minDialTimeout, maxDialTimeout)
 }
 
-func (t *transport) updateDialTimeout(newDialTime time.Duration) {
+func (t *Transport) updateDialTimeout(newDialTime time.Duration) {
 	averageTimeout(&t.avgDialTime, newDialTime, cumulativeAvgWeight)
 }
 
 // Dial dials the address configured in transport, potentially reusing a connection or creating a new one.
-func (t *transport) Dial(proto string) (*dns.Conn, bool, error) {
+func (t *Transport) Dial(proto string) (*dns.Conn, bool, error) {
 	// If tls has been configured; use it.
 	if t.tlsConfig != nil {
 		proto = "tcp-tls"

plugin/forward/forward_test.go

@@ -4,6 +4,7 @@ import (
 	"testing"
 
 	"github.com/coredns/coredns/plugin/pkg/dnstest"
+	"github.com/coredns/coredns/plugin/pkg/transport"
 	"github.com/coredns/coredns/plugin/test"
 	"github.com/coredns/coredns/request"
 
@@ -19,7 +20,7 @@ func TestForward(t *testing.T) {
 	})
 	defer s.Close()
 
-	p := NewProxy(s.Addr, DNS)
+	p := NewProxy(s.Addr, transport.DNS)
 	f := New()
 	f.SetProxy(p)
 	defer f.Close()
@@ -51,7 +52,7 @@ func TestForwardRefused(t *testing.T) {
 	})
 	defer s.Close()
 
-	p := NewProxy(s.Addr, DNS)
+	p := NewProxy(s.Addr, transport.DNS)
 	f := New()
 	f.SetProxy(p)
 	defer f.Close()

plugin/forward/health.go

@@ -5,6 +5,8 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/coredns/coredns/plugin/pkg/transport"
+
 	"github.com/miekg/dns"
 )
 
@@ -17,10 +19,10 @@ type HealthChecker interface {
 // dnsHc is a health checker for a DNS endpoint (DNS, and DoT).
 type dnsHc struct{ c *dns.Client }
 
-// NewHealthChecker returns a new HealthChecker based on protocol.
+// NewHealthChecker returns a new HealthChecker based on transport.
-func NewHealthChecker(protocol int) HealthChecker {
+func NewHealthChecker(trans string) HealthChecker {
-	switch protocol {
+	switch trans {
-	case DNS, TLS:
+	case transport.DNS, transport.TLS:
 		c := new(dns.Client)
 		c.Net = "udp"
 		c.ReadTimeout = 1 * time.Second

plugin/forward/health_test.go

@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/coredns/coredns/plugin/pkg/dnstest"
+	"github.com/coredns/coredns/plugin/pkg/transport"
 	"github.com/coredns/coredns/plugin/test"
 
 	"github.com/miekg/dns"
@@ -25,7 +26,7 @@ func TestHealth(t *testing.T) {
 	})
 	defer s.Close()
 
-	p := NewProxy(s.Addr, DNS)
+	p := NewProxy(s.Addr, transport.DNS)
 	f := New()
 	f.SetProxy(p)
 	defer f.Close()
@@ -65,7 +66,7 @@ func TestHealthTimeout(t *testing.T) {
 	})
 	defer s.Close()
 
-	p := NewProxy(s.Addr, DNS)
+	p := NewProxy(s.Addr, transport.DNS)
 	f := New()
 	f.SetProxy(p)
 	defer f.Close()
@@ -109,7 +110,7 @@ func TestHealthFailTwice(t *testing.T) {
 	})
 	defer s.Close()
 
-	p := NewProxy(s.Addr, DNS)
+	p := NewProxy(s.Addr, transport.DNS)
 	f := New()
 	f.SetProxy(p)
 	defer f.Close()
@@ -132,7 +133,7 @@ func TestHealthMaxFails(t *testing.T) {
 	})
 	defer s.Close()
 
-	p := NewProxy(s.Addr, DNS)
+	p := NewProxy(s.Addr, transport.DNS)
 	f := New()
 	f.maxfails = 2
 	f.SetProxy(p)
@@ -163,7 +164,7 @@ func TestHealthNoMaxFails(t *testing.T) {
 	})
 	defer s.Close()
 
-	p := NewProxy(s.Addr, DNS)
+	p := NewProxy(s.Addr, transport.DNS)
 	f := New()
 	f.maxfails = 0
 	f.SetProxy(p)

plugin/forward/lookup.go

@@ -7,6 +7,7 @@ package forward
 import (
 	"context"
 
+	"github.com/coredns/coredns/plugin/pkg/transport"
 	"github.com/coredns/coredns/request"
 
 	"github.com/miekg/dns"
@@ -81,7 +82,7 @@ func (f *Forward) Lookup(state request.Request, name string, typ uint16) (*dns.M
 func NewLookup(addr []string) *Forward {
 	f := New()
 	for i := range addr {
-		p := NewProxy(addr[i], DNS)
+		p := NewProxy(addr[i], transport.DNS)
 		f.SetProxy(p)
 	}
 	return f

plugin/forward/lookup_test.go

@@ -4,6 +4,7 @@ import (
 	"testing"
 
 	"github.com/coredns/coredns/plugin/pkg/dnstest"
+	"github.com/coredns/coredns/plugin/pkg/transport"
 	"github.com/coredns/coredns/plugin/test"
 	"github.com/coredns/coredns/request"
 
@@ -19,7 +20,7 @@ func TestLookup(t *testing.T) {
 	})
 	defer s.Close()
 
-	p := NewProxy(s.Addr, DNS)
+	p := NewProxy(s.Addr, transport.DNS)
 	f := New()
 	f.SetProxy(p)
 	defer f.Close()

plugin/forward/persistent.go

@@ -15,10 +15,10 @@ type persistConn struct {
 	used time.Time
 }
 
-// transport hold the persistent cache.
+// Transport hold the persistent cache.
-type transport struct {
+type Transport struct {
 	avgDialTime int64                     // kind of average time of dial time
-	conns       map[string][]*persistConn //  Buckets for udp, tcp and tcp-tls.
+	conns       map[string][]*persistConn // Buckets for udp, tcp and tcp-tls.
 	expire      time.Duration             // After this duration a connection is expired.
 	addr        string
 	tlsConfig   *tls.Config
@@ -29,8 +29,8 @@ type transport struct {
 	stop  chan bool
 }
 
-func newTransport(addr string) *transport {
+func newTransport(addr string) *Transport {
-	t := &transport{
+	t := &Transport{
 		avgDialTime: int64(defaultDialTimeout / 2),
 		conns:       make(map[string][]*persistConn),
 		expire:      defaultExpire,
@@ -45,7 +45,7 @@ func newTransport(addr string) *transport {
 
 // len returns the number of connection, used for metrics. Can only be safely
 // used inside connManager() because of data races.
-func (t *transport) len() int {
+func (t *Transport) len() int {
 	l := 0
 	for _, conns := range t.conns {
 		l += len(conns)
@@ -54,7 +54,7 @@ func (t *transport) len() int {
 }
 
 // connManagers manages the persistent connection cache for UDP and TCP.
-func (t *transport) connManager() {
+func (t *Transport) connManager() {
 	ticker := time.NewTicker(t.expire)
 Wait:
 	for {
@@ -115,7 +115,7 @@ func closeConns(conns []*persistConn) {
 }
 
 // cleanup removes connections from cache.
-func (t *transport) cleanup(all bool) {
+func (t *Transport) cleanup(all bool) {
 	staleTime := time.Now().Add(-t.expire)
 	for proto, stack := range t.conns {
 		if len(stack) == 0 {
@@ -144,19 +144,19 @@ func (t *transport) cleanup(all bool) {
 }
 
 // Yield return the connection to transport for reuse.
-func (t *transport) Yield(c *dns.Conn) { t.yield <- c }
+func (t *Transport) Yield(c *dns.Conn) { t.yield <- c }
 
 // Start starts the transport's connection manager.
-func (t *transport) Start() { go t.connManager() }
+func (t *Transport) Start() { go t.connManager() }
 
 // Stop stops the transport's connection manager.
-func (t *transport) Stop() { close(t.stop) }
+func (t *Transport) Stop() { close(t.stop) }
 
 // SetExpire sets the connection expire time in transport.
-func (t *transport) SetExpire(expire time.Duration) { t.expire = expire }
+func (t *Transport) SetExpire(expire time.Duration) { t.expire = expire }
 
 // SetTLSConfig sets the TLS config in transport.
-func (t *transport) SetTLSConfig(cfg *tls.Config) { t.tlsConfig = cfg }
+func (t *Transport) SetTLSConfig(cfg *tls.Config) { t.tlsConfig = cfg }
 
 const (
 	defaultExpire      = 10 * time.Second

plugin/forward/protocol.go

@@ -1,30 +0,0 @@
-package forward
-
-// Copied from coredns/core/dnsserver/address.go
-
-import (
-	"strings"
-)
-
-// protocol returns the protocol of the string s. The second string returns s
-// with the prefix chopped off.
-func protocol(s string) (int, string) {
-	switch {
-	case strings.HasPrefix(s, _tls+"://"):
-		return TLS, s[len(_tls)+3:]
-	case strings.HasPrefix(s, _dns+"://"):
-		return DNS, s[len(_dns)+3:]
-	}
-	return DNS, s
-}
-
-// Supported protocols.
-const (
-	DNS = iota + 1
-	TLS
-)
-
-const (
-	_dns = "dns"
-	_tls = "tls"
-)

plugin/forward/proxy.go

@@ -18,7 +18,7 @@ type Proxy struct {
 
 	// Connection caching
 	expire    time.Duration
-	transport *transport
+	transport *Transport
 
 	// health checking
 	probe  *up.Probe
@@ -26,7 +26,7 @@ type Proxy struct {
 }
 
 // NewProxy returns a new proxy.
-func NewProxy(addr string, protocol int) *Proxy {
+func NewProxy(addr, trans string) *Proxy {
 	p := &Proxy{
 		addr:      addr,
 		fails:     0,
@@ -34,7 +34,7 @@ func NewProxy(addr string, protocol int) *Proxy {
 		transport: newTransport(addr),
 		avgRtt:    int64(maxTimeout / 2),
 	}
-	p.health = NewHealthChecker(protocol)
+	p.health = NewHealthChecker(trans)
 	runtime.SetFinalizer(p, (*Proxy).finalizer)
 	return p
 }

plugin/forward/proxy_test.go

@@ -5,6 +5,7 @@ import (
 	"testing"
 
 	"github.com/coredns/coredns/plugin/pkg/dnstest"
+	"github.com/coredns/coredns/plugin/pkg/transport"
 	"github.com/coredns/coredns/plugin/test"
 	"github.com/coredns/coredns/request"
 
@@ -26,7 +27,7 @@ func TestProxyClose(t *testing.T) {
 	ctx := context.TODO()
 
 	for i := 0; i < 100; i++ {
-		p := NewProxy(s.Addr, DNS)
+		p := NewProxy(s.Addr, transport.DNS)
 		p.start(hcInterval)
 
 		go func() { p.Connect(ctx, state, options{}) }()
@@ -95,7 +96,7 @@ func TestProxyTLSFail(t *testing.T) {
 }
 
 func TestProtocolSelection(t *testing.T) {
-	p := NewProxy("bad_address", DNS)
+	p := NewProxy("bad_address", transport.DNS)
 
 	stateUDP := request.Request{W: &test.ResponseWriter{}, Req: new(dns.Msg)}
 	stateTCP := request.Request{W: &test.ResponseWriter{TCP: true}, Req: new(dns.Msg)}

plugin/forward/setup.go

@@ -2,7 +2,6 @@ package forward
 
 import (
 	"fmt"
-	"net"
 	"strconv"
 	"time"
 
@@ -11,6 +10,7 @@ import (
 	"github.com/coredns/coredns/plugin/metrics"
 	"github.com/coredns/coredns/plugin/pkg/dnsutil"
 	pkgtls "github.com/coredns/coredns/plugin/pkg/tls"
+	"github.com/coredns/coredns/plugin/pkg/transport"
 
 	"github.com/mholt/caddy"
 	"github.com/mholt/caddy/caddyfile"
@@ -93,8 +93,6 @@ func parseForward(c *caddy.Controller) (*Forward, error) {
 func ParseForwardStanza(c *caddyfile.Dispenser) (*Forward, error) {
 	f := New()
 
-	protocols := map[int]int{}
-
 	if !c.Args(&f.from) {
 		return f, c.ArgErr()
 	}
@@ -105,41 +103,17 @@ func ParseForwardStanza(c *caddyfile.Dispenser) (*Forward, error) {
 		return f, c.ArgErr()
 	}
 
-	// A bit fiddly, but first check if we've got protocols and if so add them back in when we create the proxies.
-	protocols = make(map[int]int)
-	for i := range to {
-		protocols[i], to[i] = protocol(to[i])
-	}
-
-	// If parseHostPortOrFile expands a file with a lot of nameserver our accounting in protocols doesn't make
-	// any sense anymore... For now: lets don't care.
 	toHosts, err := dnsutil.ParseHostPortOrFile(to...)
 	if err != nil {
 		return f, err
 	}
 
-	for i, h := range toHosts {
+	transports := make([]string, len(toHosts))
-		// Double check the port, if e.g. is 53 and the transport is TLS make it 853.
+	for i, host := range toHosts {
-		// This can be somewhat annoying because you *can't* have TLS on port 53 then.
+		trans, h := transport.Parse(host)
-		switch protocols[i] {
+		p := NewProxy(h, trans)
-		case TLS:
-			h1, p, err := net.SplitHostPort(h)
-			if err != nil {
-				break
-			}
-
-			// This is more of a bug in dnsutil.ParseHostPortOrFile that defaults to
-			// 53 because it doesn't know about the tls:// // and friends (that should be fixed). Hence
-			// Fix the port number here, back to what the user intended.
-			if p == "53" {
-				h = net.JoinHostPort(h1, "853")
-			}
-		}
-
-		// We can't set tlsConfig here, because we haven't parsed it yet.
-		// We set it below at the end of parseBlock, use nil now.
-		p := NewProxy(h, protocols[i])
 		f.proxies = append(f.proxies, p)
+		transports[i] = trans
 	}
 
 	for c.NextBlock() {
@@ -153,7 +127,7 @@ func ParseForwardStanza(c *caddyfile.Dispenser) (*Forward, error) {
 	}
 	for i := range f.proxies {
 		// Only set this for proxies that need it.
-		if protocols[i] == TLS {
+		if transports[i] == transport.TLS {
 			f.proxies[i].SetTLSConfig(f.tlsConfig)
 		}
 		f.proxies[i].SetExpire(f.expire)

plugin/forward/truncated_test.go

@@ -5,6 +5,7 @@ import (
 	"testing"
 
 	"github.com/coredns/coredns/plugin/pkg/dnstest"
+	"github.com/coredns/coredns/plugin/pkg/transport"
 	"github.com/coredns/coredns/plugin/test"
 	"github.com/coredns/coredns/request"
 
@@ -34,7 +35,7 @@ func TestLookupTruncated(t *testing.T) {
 	})
 	defer s.Close()
 
-	p := NewProxy(s.Addr, DNS)
+	p := NewProxy(s.Addr, transport.DNS)
 	f := New()
 	f.SetProxy(p)
 	defer f.Close()
@@ -88,9 +89,9 @@ func TestForwardTruncated(t *testing.T) {
 
 	f := New()
 
-	p1 := NewProxy(s.Addr, DNS)
+	p1 := NewProxy(s.Addr, transport.DNS)
 	f.SetProxy(p1)
-	p2 := NewProxy(s.Addr, DNS)
+	p2 := NewProxy(s.Addr, transport.DNS)
 	f.SetProxy(p2)
 	defer f.Close()
 

plugin/normalize.go

@@ -6,6 +6,8 @@ import (
 	"strconv"
 	"strings"
 
+	"github.com/coredns/coredns/plugin/pkg/transport"
+
 	"github.com/miekg/dns"
 )
 
@@ -61,22 +63,10 @@ type (
 // Normalize will return the host portion of host, stripping
 // of any port or transport. The host will also be fully qualified and lowercased.
 func (h Host) Normalize() string {
-
 	s := string(h)
+	_, s = transport.Parse(s)
 
-	switch {
+	// The error can be ignore here, because this function is called after the corefile has already been vetted.
-	case strings.HasPrefix(s, TransportTLS+"://"):
-		s = s[len(TransportTLS+"://"):]
-	case strings.HasPrefix(s, TransportDNS+"://"):
-		s = s[len(TransportDNS+"://"):]
-	case strings.HasPrefix(s, TransportGRPC+"://"):
-		s = s[len(TransportGRPC+"://"):]
-	case strings.HasPrefix(s, TransportHTTPS+"://"):
-		s = s[len(TransportHTTPS+"://"):]
-	}
-
-	// The error can be ignore here, because this function is called after the corefile
-	// has already been vetted.
 	host, _, _, _ := SplitHostPort(s)
 	return Name(host).Normalize()
 }
@@ -138,11 +128,3 @@ func SplitHostPort(s string) (host, port string, ipnet *net.IPNet, err error) {
 	}
 	return host, port, n, nil
 }
-
-// Duplicated from core/dnsserver/address.go !
-const (
-	TransportDNS   = "dns"
-	TransportTLS   = "tls"
-	TransportGRPC  = "grpc"
-	TransportHTTPS = "https"
-)

plugin/pkg/dnsutil/host.go

@@ -5,15 +5,21 @@ import (
 	"net"
 	"os"
 
+	"github.com/coredns/coredns/plugin/pkg/transport"
+
 	"github.com/miekg/dns"
 )
 
-// ParseHostPortOrFile parses the strings in s, each string can either be a address,
+// ParseHostPortOrFile parses the strings in s, each string can either be a
-// address:port or a filename. The address part is checked and the filename case a
+// address, [scheme://]address:port or a filename. The address part is checked
-// resolv.conf like file is parsed and the nameserver found are returned.
+// and in case of filename a resolv.conf like file is (assumed) and parsed and
+// the nameservers found are returned.
 func ParseHostPortOrFile(s ...string) ([]string, error) {
 	var servers []string
-	for _, host := range s {
+	for _, h := range s {
+
+		trans, host := transport.Parse(h)
+
 		addr, _, err := net.SplitHostPort(host)
 		if err != nil {
 			// Parse didn't work, it is not a addr:port combo
@@ -26,13 +32,23 @@ func ParseHostPortOrFile(s ...string) ([]string, error) {
 				}
 				return servers, fmt.Errorf("not an IP address or file: %q", host)
 			}
-			ss := net.JoinHostPort(host, "53")
+			var ss string
+			switch trans {
+			case transport.DNS:
+				ss = net.JoinHostPort(host, "53")
+			case transport.TLS:
+				ss = transport.TLS + "://" + net.JoinHostPort(host, transport.TLSPort)
+			case transport.GRPC:
+				ss = transport.GRPC + "://" + net.JoinHostPort(host, transport.GRPCPort)
+			case transport.HTTPS:
+				ss = transport.HTTPS + "://" + net.JoinHostPort(host, transport.HTTPSPort)
+			}
 			servers = append(servers, ss)
 			continue
 		}
 
 		if net.ParseIP(addr) == nil {
-			// No an IP address.
+			// Not an IP address.
 			ss, err := tryFile(host)
 			if err == nil {
 				servers = append(servers, ss...)
@@ -40,7 +56,7 @@ func ParseHostPortOrFile(s ...string) ([]string, error) {
 			}
 			return servers, fmt.Errorf("not an IP address or file: %q", host)
 		}
-		servers = append(servers, host)
+		servers = append(servers, h)
 	}
 	return servers, nil
 }

plugin/pkg/transport/transport.go

@@ -0,0 +1,49 @@
+package transport
+
+import (
+	"strings"
+)
+
+// Parse returns the transport defined in s and a string where the
+// transport prefix is removed (if there was any). If no transport is defined
+// we default to TransportDNS
+func Parse(s string) (transport string, addr string) {
+	switch {
+	case strings.HasPrefix(s, TLS+"://"):
+		s = s[len(TLS+"://"):]
+		return TLS, s
+
+	case strings.HasPrefix(s, DNS+"://"):
+		s = s[len(DNS+"://"):]
+		return DNS, s
+
+	case strings.HasPrefix(s, GRPC+"://"):
+		s = s[len(GRPC+"://"):]
+		return GRPC, s
+
+	case strings.HasPrefix(s, HTTPS+"://"):
+		s = s[len(HTTPS+"://"):]
+
+		return HTTPS, s
+	}
+
+	return DNS, s
+}
+
+// Supported transports.
+const (
+	DNS   = "dns"
+	TLS   = "tls"
+	GRPC  = "grpc"
+	HTTPS = "https"
+)
+
+// Port numbers for the various protocols
+const (
+	// TLSPort is the default port for DNS-over-TLS.
+	TLSPort = "853"
+	// GRPCPort is the default port for DNS-over-gRPC.
+	GRPCPort = "443"
+	// HTTPSPort is the default port for DNS-over-HTTPS.
+	HTTPSPort = "443"
+)

plugin/pkg/transport/transport_test.go

@@ -0,0 +1,21 @@
+package transport
+
+import "testing"
+
+func TestParse(t *testing.T) {
+	for i, test := range []struct {
+		input    string
+		expected string
+	}{
+		{"dns://.:53", DNS},
+		{"2003::1/64.:53", DNS},
+		{"grpc://example.org:1443 ", GRPC},
+		{"tls://example.org ", TLS},
+		{"https://example.org ", HTTPS},
+	} {
+		actual, _ := Parse(test.input)
+		if actual != test.expected {
+			t.Errorf("Test %d: Expected %s but got %s", i, test.expected, actual)
+		}
+	}
+}