Make timeout error derived from DeadlineExceeded

Add Go 1.13 error wrapping compatible error wrapper and
make errConnectTimeout derived from context.DeadlineExceeded.

conn_go_test.go

@@ -0,0 +1,146 @@
+// +build !js
+
+package dtls
+
+import (
+	"bytes"
+	"context"
+	"crypto/tls"
+	"net"
+	"testing"
+	"time"
+
+	"github.com/pion/dtls/v2/pkg/crypto/selfsign"
+)
+
+func TestContextConfig(t *testing.T) {
+	addrListen, err := net.ResolveUDPAddr("udp", "localhost:0")
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+
+	// Dummy listener
+	listen, err := net.ListenUDP("udp", addrListen)
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+	defer func() {
+		_ = listen.Close()
+	}()
+	addr := listen.LocalAddr().(*net.UDPAddr)
+
+	cert, err := selfsign.GenerateSelfSigned()
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+	config := &Config{
+		ConnectContextMaker: func() (context.Context, func()) {
+			return context.WithTimeout(context.Background(), 40*time.Millisecond)
+		},
+		Certificates: []tls.Certificate{cert},
+	}
+
+	dials := map[string]struct {
+		f     func() (net.Conn, error)
+		order []byte
+	}{
+		"Dial": {
+			f: func() (net.Conn, error) {
+				return Dial("udp", addr, config)
+			},
+			order: []byte{0, 1, 2},
+		},
+		"DialWithContext": {
+			f: func() (net.Conn, error) {
+				ctx, cancel := context.WithTimeout(context.Background(), 60*time.Millisecond)
+				defer cancel()
+				return DialWithContext(ctx, "udp", addr, config)
+			},
+			order: []byte{0, 2, 1},
+		},
+		"Client": {
+			f: func() (net.Conn, error) {
+				ca, _ := net.Pipe()
+				defer func() {
+					_ = ca.Close()
+				}()
+				return Client(ca, config)
+			},
+			order: []byte{0, 1, 2},
+		},
+		"ClientWithContext": {
+			f: func() (net.Conn, error) {
+				ctx, cancel := context.WithTimeout(context.Background(), 60*time.Millisecond)
+				defer cancel()
+				ca, _ := net.Pipe()
+				defer func() {
+					_ = ca.Close()
+				}()
+				return ClientWithContext(ctx, ca, config)
+			},
+			order: []byte{0, 2, 1},
+		},
+		"Server": {
+			f: func() (net.Conn, error) {
+				ca, _ := net.Pipe()
+				defer func() {
+					_ = ca.Close()
+				}()
+				return Server(ca, config)
+			},
+			order: []byte{0, 1, 2},
+		},
+		"ServerWithContext": {
+			f: func() (net.Conn, error) {
+				ctx, cancel := context.WithTimeout(context.Background(), 60*time.Millisecond)
+				defer cancel()
+				ca, _ := net.Pipe()
+				defer func() {
+					_ = ca.Close()
+				}()
+				return ServerWithContext(ctx, ca, config)
+			},
+			order: []byte{0, 2, 1},
+		},
+	}
+
+	for name, dial := range dials {
+		dial := dial
+		t.Run(name, func(t *testing.T) {
+			done := make(chan struct{})
+
+			go func() {
+				conn, err := dial.f()
+				if err != errConnectTimeout {
+					t.Errorf("Expected error: '%v', got: '%v'", errConnectTimeout, err)
+					close(done)
+					return
+				}
+				done <- struct{}{}
+				_ = conn.Close()
+			}()
+
+			var order []byte
+			early := time.After(30 * time.Millisecond)
+			late := time.After(50 * time.Millisecond)
+			func() {
+				for len(order) < 3 {
+					select {
+					case <-early:
+						order = append(order, 0)
+					case _, ok := <-done:
+						if !ok {
+							return
+						}
+						order = append(order, 1)
+					case <-late:
+						order = append(order, 2)
+					}
+				}
+			}()
+			if !bytes.Equal(dial.order, order) {
+				t.Errorf("Invalid cancel timing, expected: %v, got: %v", dial.order, order)
+			}
+		})
+	}
+}

errors.go

@@ -1,6 +1,11 @@
 package dtls
 
-import "errors"
+import (
+	"context"
+	"errors"
+
+	"golang.org/x/xerrors"
+)
 
 // Typed errors
 var (
@@ -50,11 +55,13 @@ var (
 	errNoAvailableCipherSuites           = errors.New("dtls: Connection can not be created, no CipherSuites satisfy this Config")
 	errInvalidClientKeyExchange          = errors.New("dtls: Unable to determine if ClientKeyExchange is a public key or PSK Identity")
 	errNoSupportedEllipticCurves         = errors.New("dtls: Client requested zero or more elliptic curves that are not supported by the server")
-	errConnectTimeout                    = errors.New("dtls: The connection timed out during the handshake")
 	errRequestedButNoSRTPExtension       = errors.New("dtls: SRTP support was requested but server did not respond with use_srtp extension")
 	errClientNoMatchingSRTPProfile       = errors.New("dtls: Server responded with SRTP Profile we do not support")
 	errServerNoMatchingSRTPProfile       = errors.New("dtls: Client requested SRTP but we have no matching profiles")
 	errServerRequiredButNoClientEMS      = errors.New("dtls: Server requires the Extended Master Secret extension, but the client does not support it")
 	errClientRequiredButNoServerEMS      = errors.New("dtls: Client required Extended Master Secret extension, but server does not support it")
 	errInvalidCertificate                = errors.New("dtls: No certificate provided")
+
+	// Wrapped errors
+	errConnectTimeout = xerrors.Errorf("dtls: The connection timed out during the handshake: %w", context.DeadlineExceeded)
 )

go.mod

@@ -5,6 +5,7 @@ require (
 	github.com/pion/transport v0.8.10
 	golang.org/x/crypto v0.0.0-20200128174031-69ecbb4d6d5d
 	golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3
+	golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543
 )
 
 go 1.13

go.sum

@@ -14,5 +14,7 @@ golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=