Support TsigProvider for Server and Transfer

client.go

@@ -39,6 +39,14 @@ type Conn struct {
 	tsigRequestMAC string
 }
 
+func (co *Conn) tsigProvider() TsigProvider {
+	if co.TsigProvider != nil {
+		return co.TsigProvider
+	}
+	// tsigSecretProvider will return ErrSecret if co.TsigSecret is nil.
+	return tsigSecretProvider(co.TsigSecret)
+}
+
 // A Client defines parameters for a DNS client.
 type Client struct {
 	Net       string      // if "tcp" or "tcp-tls" (DNS over TLS) a TCP query will be initiated, otherwise an UDP one (default is "" for UDP)
@@ -271,15 +279,8 @@ func (co *Conn) ReadMsg() (*Msg, error) {
 		return m, err
 	}
 	if t := m.IsTsig(); t != nil {
-		if co.TsigProvider != nil {
-			err = tsigVerifyProvider(p, co.TsigProvider, co.tsigRequestMAC, false)
-		} else {
-			if _, ok := co.TsigSecret[t.Hdr.Name]; !ok {
-				return m, ErrSecret
-			}
-			// Need to work on the original message p, as that was used to calculate the tsig.
-			err = TsigVerify(p, co.TsigSecret[t.Hdr.Name], co.tsigRequestMAC, false)
-		}
+		// Need to work on the original message p, as that was used to calculate the tsig.
+		err = tsigVerifyProvider(p, co.tsigProvider(), co.tsigRequestMAC, false)
 	}
 	return m, err
 }
@@ -356,17 +357,8 @@ func (co *Conn) Read(p []byte) (n int, err error) {
 func (co *Conn) WriteMsg(m *Msg) (err error) {
 	var out []byte
 	if t := m.IsTsig(); t != nil {
-		mac := ""
-		if co.TsigProvider != nil {
-			out, mac, err = tsigGenerateProvider(m, co.TsigProvider, co.tsigRequestMAC, false)
-		} else {
-			if _, ok := co.TsigSecret[t.Hdr.Name]; !ok {
-				return ErrSecret
-			}
-			out, mac, err = TsigGenerate(m, co.TsigSecret[t.Hdr.Name], co.tsigRequestMAC, false)
-		}
-		// Set for the next read, although only used in zone transfers
-		co.tsigRequestMAC = mac
+		// Set tsigRequestMAC for the next read, although only used in zone transfers.
+		out, co.tsigRequestMAC, err = tsigGenerateProvider(m, co.tsigProvider(), co.tsigRequestMAC, false)
 	} else {
 		out, err = m.Pack()
 	}

server.go

@@ -71,12 +71,12 @@ type response struct {
 	tsigTimersOnly bool
 	tsigStatus     error
 	tsigRequestMAC string
-	tsigSecret     map[string]string // the tsig secrets
-	udp            net.PacketConn    // i/o connection if UDP was used
-	tcp            net.Conn          // i/o connection if TCP was used
-	udpSession     *SessionUDP       // oob data to get egress interface right
-	pcSession      net.Addr          // address to use when writing to a generic net.PacketConn
-	writer         Writer            // writer to output the raw DNS bits
+	tsigProvider   TsigProvider
+	udp            net.PacketConn // i/o connection if UDP was used
+	tcp            net.Conn       // i/o connection if TCP was used
+	udpSession     *SessionUDP    // oob data to get egress interface right
+	pcSession      net.Addr       // address to use when writing to a generic net.PacketConn
+	writer         Writer         // writer to output the raw DNS bits
 }
 
 // handleRefused returns a HandlerFunc that returns REFUSED for every request it gets.
@@ -211,6 +211,8 @@ type Server struct {
 	WriteTimeout time.Duration
 	// TCP idle timeout for multiple queries, if nil, defaults to 8 * time.Second (RFC 5966).
 	IdleTimeout func() time.Duration
+	// An implementation of the TsigProvider interface. If defined it replaces TsigSecret and is used for all TSIG operations.
+	TsigProvider TsigProvider
 	// Secret(s) for Tsig map[<zonename>]<base64 secret>. The zonename must be in canonical form (lowercase, fqdn, see RFC 4034 Section 6.2).
 	TsigSecret map[string]string
 	// If NotifyStartedFunc is set it is called once the server has started listening.
@@ -238,6 +240,16 @@ type Server struct {
 	udpPool sync.Pool
 }
 
+func (srv *Server) tsigProvider() TsigProvider {
+	if srv.TsigProvider != nil {
+		return srv.TsigProvider
+	}
+	if srv.TsigSecret != nil {
+		return tsigSecretProvider(srv.TsigSecret)
+	}
+	return nil
+}
+
 func (srv *Server) isStarted() bool {
 	srv.lock.RLock()
 	started := srv.started
@@ -526,7 +538,7 @@ func (srv *Server) serveUDP(l net.PacketConn) error {
 
 // Serve a new TCP connection.
 func (srv *Server) serveTCPConn(wg *sync.WaitGroup, rw net.Conn) {
-	w := &response{tsigSecret: srv.TsigSecret, tcp: rw}
+	w := &response{tsigProvider: srv.tsigProvider(), tcp: rw}
 	if srv.DecorateWriter != nil {
 		w.writer = srv.DecorateWriter(w)
 	} else {
@@ -581,7 +593,7 @@ func (srv *Server) serveTCPConn(wg *sync.WaitGroup, rw net.Conn) {
 
 // Serve a new UDP request.
 func (srv *Server) serveUDPPacket(wg *sync.WaitGroup, m []byte, u net.PacketConn, udpSession *SessionUDP, pcSession net.Addr) {
-	w := &response{tsigSecret: srv.TsigSecret, udp: u, udpSession: udpSession, pcSession: pcSession}
+	w := &response{tsigProvider: srv.tsigProvider(), udp: u, udpSession: udpSession, pcSession: pcSession}
 	if srv.DecorateWriter != nil {
 		w.writer = srv.DecorateWriter(w)
 	} else {
@@ -632,15 +644,11 @@ func (srv *Server) serveDNS(m []byte, w *response) {
 	}
 
 	w.tsigStatus = nil
-	if w.tsigSecret != nil {
+	if w.tsigProvider != nil {
 		if t := req.IsTsig(); t != nil {
-			if secret, ok := w.tsigSecret[t.Hdr.Name]; ok {
-				w.tsigStatus = TsigVerify(m, secret, "", false)
-			} else {
-				w.tsigStatus = ErrSecret
-			}
+			w.tsigStatus = tsigVerifyProvider(m, w.tsigProvider, "", false)
 			w.tsigTimersOnly = false
-			w.tsigRequestMAC = req.Extra[len(req.Extra)-1].(*TSIG).MAC
+			w.tsigRequestMAC = t.MAC
 		}
 	}
 
@@ -718,9 +726,9 @@ func (w *response) WriteMsg(m *Msg) (err error) {
 	}
 
 	var data []byte
-	if w.tsigSecret != nil { // if no secrets, dont check for the tsig (which is a longer check)
+	if w.tsigProvider != nil { // if no provider, dont check for the tsig (which is a longer check)
 		if t := m.IsTsig(); t != nil {
-			data, w.tsigRequestMAC, err = TsigGenerate(m, w.tsigSecret[t.Hdr.Name], w.tsigRequestMAC, w.tsigTimersOnly)
+			data, w.tsigRequestMAC, err = tsigGenerateProvider(m, w.tsigProvider, w.tsigRequestMAC, w.tsigTimersOnly)
 			if err != nil {
 				return err
 			}

tsig.go

@@ -74,6 +74,24 @@ func (key tsigHMACProvider) Verify(msg []byte, t *TSIG) error {
 	return nil
 }
 
+type tsigSecretProvider map[string]string
+
+func (ts tsigSecretProvider) Generate(msg []byte, t *TSIG) ([]byte, error) {
+	key, ok := ts[t.Hdr.Name]
+	if !ok {
+		return nil, ErrSecret
+	}
+	return tsigHMACProvider(key).Generate(msg, t)
+}
+
+func (ts tsigSecretProvider) Verify(msg []byte, t *TSIG) error {
+	key, ok := ts[t.Hdr.Name]
+	if !ok {
+		return ErrSecret
+	}
+	return tsigHMACProvider(key).Verify(msg, t)
+}
+
 // TSIG is the RR the holds the transaction signature of a message.
 // See RFC 2845 and RFC 4635.
 type TSIG struct {

xfr.go

@@ -17,11 +17,22 @@ type Transfer struct {
 	DialTimeout    time.Duration     // net.DialTimeout, defaults to 2 seconds
 	ReadTimeout    time.Duration     // net.Conn.SetReadTimeout value for connections, defaults to 2 seconds
 	WriteTimeout   time.Duration     // net.Conn.SetWriteTimeout value for connections, defaults to 2 seconds
+	TsigProvider   TsigProvider      // An implementation of the TsigProvider interface. If defined it replaces TsigSecret and is used for all TSIG operations.
 	TsigSecret     map[string]string // Secret(s) for Tsig map[<zonename>]<base64 secret>, zonename must be in canonical form (lowercase, fqdn, see RFC 4034 Section 6.2)
 	tsigTimersOnly bool
 }
 
-// Think we need to away to stop the transfer
+func (t *Transfer) tsigProvider() TsigProvider {
+	if t.TsigProvider != nil {
+		return t.TsigProvider
+	}
+	if t.TsigSecret != nil {
+		return tsigSecretProvider(t.TsigSecret)
+	}
+	return nil
+}
+
+// TODO: Think we need to away to stop the transfer
 
 // In performs an incoming transfer with the server in a.
 // If you would like to set the source IP, or some other attribute
@@ -224,12 +235,9 @@ func (t *Transfer) ReadMsg() (*Msg, error) {
 	if err := m.Unpack(p); err != nil {
 		return nil, err
 	}
-	if ts := m.IsTsig(); ts != nil && t.TsigSecret != nil {
-		if _, ok := t.TsigSecret[ts.Hdr.Name]; !ok {
-			return m, ErrSecret
-		}
+	if ts, tp := m.IsTsig(), t.tsigProvider(); ts != nil && tp != nil {
 		// Need to work on the original message p, as that was used to calculate the tsig.
-		err = TsigVerify(p, t.TsigSecret[ts.Hdr.Name], t.tsigRequestMAC, t.tsigTimersOnly)
+		err = tsigVerifyProvider(p, tp, t.tsigRequestMAC, t.tsigTimersOnly)
 		t.tsigRequestMAC = ts.MAC
 	}
 	return m, err
@@ -238,11 +246,8 @@ func (t *Transfer) ReadMsg() (*Msg, error) {
 // WriteMsg writes a message through the transfer connection t.
 func (t *Transfer) WriteMsg(m *Msg) (err error) {
 	var out []byte
-	if ts := m.IsTsig(); ts != nil && t.TsigSecret != nil {
-		if _, ok := t.TsigSecret[ts.Hdr.Name]; !ok {
-			return ErrSecret
-		}
-		out, t.tsigRequestMAC, err = TsigGenerate(m, t.TsigSecret[ts.Hdr.Name], t.tsigRequestMAC, t.tsigTimersOnly)
+	if ts, tp := m.IsTsig(), t.tsigProvider(); ts != nil && tp != nil {
+		out, t.tsigRequestMAC, err = tsigGenerateProvider(m, tp, t.tsigRequestMAC, t.tsigTimersOnly)
 	} else {
 		out, err = m.Pack()
 	}

xfr_test.go

@@ -1,6 +1,9 @@
 package dns
 
-import "testing"
+import (
+	"testing"
+	"time"
+)
 
 var (
 	tsigSecret  = map[string]string{"axfr.": "so6ZGir4GPAqINNh9U5c3A=="}
@@ -127,3 +130,54 @@ func axfrTestingSuite(t *testing.T, addrstr string) {
 		}
 	}
 }
+
+func axfrTestingSuiteWithCustomTsig(t *testing.T, addrstr string, provider TsigProvider) {
+	tr := new(Transfer)
+	m := new(Msg)
+	var err error
+	tr.Conn, err = Dial("tcp", addrstr)
+	if err != nil {
+		t.Fatal("failed to dial", err)
+	}
+	tr.TsigProvider = provider
+	m.SetAxfr("miek.nl.")
+	m.SetTsig("axfr.", HmacSHA256, 300, time.Now().Unix())
+
+	c, err := tr.In(m, addrstr)
+	if err != nil {
+		t.Fatal("failed to zone transfer in", err)
+	}
+
+	var records []RR
+	for msg := range c {
+		if msg.Error != nil {
+			t.Fatal(msg.Error)
+		}
+		records = append(records, msg.RR...)
+	}
+
+	if len(records) != len(xfrTestData) {
+		t.Fatalf("bad axfr: expected %v, got %v", records, xfrTestData)
+	}
+
+	for i, rr := range records {
+		if !IsDuplicate(rr, xfrTestData[i]) {
+			t.Errorf("bad axfr: expected %v, got %v", records, xfrTestData)
+		}
+	}
+}
+
+func TestCustomTsigProvider(t *testing.T) {
+	HandleFunc("miek.nl.", SingleEnvelopeXfrServer)
+	defer HandleRemove("miek.nl.")
+
+	s, addrstr, _, err := RunLocalTCPServer(":0", func(srv *Server) {
+		srv.TsigProvider = tsigSecretProvider(tsigSecret)
+	})
+	if err != nil {
+		t.Fatalf("unable to run test server: %s", err)
+	}
+	defer s.Shutdown()
+
+	axfrTestingSuiteWithCustomTsig(t, addrstr, tsigSecretProvider(tsigSecret))
+}