TUN-2606: add DialEdge helpers

connection/connection.go

@@ -2,7 +2,6 @@ package connection
 
 import (
 	"context"
-	"net"
 	"time"
 
 	"github.com/cloudflare/cloudflared/h2mux"
@@ -20,20 +19,12 @@ const (
 	openStreamTimeout = 30 * time.Second
 )
 
-type dialError struct {
-	cause error
-}
-
-func (e dialError) Error() string {
-	return e.cause.Error()
-}
-
 type Connection struct {
 	id    uuid.UUID
 	muxer *h2mux.Muxer
 }
 
-func newConnection(muxer *h2mux.Muxer, edgeIP *net.TCPAddr) (*Connection, error) {
+func newConnection(muxer *h2mux.Muxer) (*Connection, error) {
 	id, err := uuid.NewRandom()
 	if err != nil {
 		return nil, err

connection/dial.go

@@ -0,0 +1,54 @@
+package connection
+
+import (
+	"context"
+	"crypto/tls"
+	"net"
+	"time"
+
+	"github.com/pkg/errors"
+)
+
+// DialEdge makes a TLS connection to a Cloudflare edge node
+func DialEdge(
+	ctx context.Context,
+	timeout time.Duration,
+	tlsConfig *tls.Config,
+	edgeTCPAddr *net.TCPAddr,
+) (net.Conn, error) {
+	// Inherit from parent context so we can cancel (Ctrl-C) while dialing
+	dialCtx, dialCancel := context.WithTimeout(ctx, timeout)
+	defer dialCancel()
+
+	dialer := net.Dialer{}
+	edgeConn, err := dialer.DialContext(dialCtx, "tcp", edgeTCPAddr.String())
+	if err != nil {
+		return nil, newDialError(err, "DialContext error")
+	}
+	tlsEdgeConn := tls.Client(edgeConn, tlsConfig)
+	tlsEdgeConn.SetDeadline(time.Now().Add(timeout))
+
+	if err = tlsEdgeConn.Handshake(); err != nil {
+		return nil, newDialError(err, "Handshake with edge error")
+	}
+	// clear the deadline on the conn; h2mux has its own timeouts
+	tlsEdgeConn.SetDeadline(time.Time{})
+	return tlsEdgeConn, nil
+}
+
+// DialError is an error returned from DialEdge
+type DialError struct {
+	cause error
+}
+
+func newDialError(err error, message string) error {
+	return DialError{cause: errors.Wrap(err, message)}
+}
+
+func (e DialError) Error() string {
+	return e.cause.Error()
+}
+
+func (e DialError) Cause() error {
+	return e.cause
+}

connection/manager.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"crypto/tls"
 	"fmt"
-	"net"
 	"sync"
 	"time"
 
@@ -128,12 +127,12 @@ func (em *EdgeManager) UpdateConfigurable(newConfigurable *EdgeManagerConfigurab
 }
 
 func (em *EdgeManager) newConnection(ctx context.Context) *pogs.ConnectError {
-	edgeIP := em.serviceDiscoverer.Addr()
-	edgeConn, err := em.dialEdge(ctx, edgeIP)
+	edgeTCPAddr := em.serviceDiscoverer.Addr()
+	configurable := em.state.getConfigurable()
+	edgeConn, err := DialEdge(ctx, configurable.Timeout, em.tlsConfig, edgeTCPAddr)
 	if err != nil {
 		return retryConnection(fmt.Sprintf("dial edge error: %v", err))
 	}
-	configurable := em.state.getConfigurable()
 	// Establish a muxed connection with the edge
 	// Client mux handshake with agent server
 	muxer, err := h2mux.Handshake(edgeConn, edgeConn, h2mux.MuxerConfig{
@@ -148,7 +147,7 @@ func (em *EdgeManager) newConnection(ctx context.Context) *pogs.ConnectError {
 		retryConnection(fmt.Sprintf("couldn't perform handshake with edge: %v", err))
 	}
 
-	h2muxConn, err := newConnection(muxer, edgeIP)
+	h2muxConn, err := newConnection(muxer)
 	if err != nil {
 		return retryConnection(fmt.Sprintf("couldn't create h2mux connection: %v", err))
 	}
@@ -196,28 +195,6 @@ func (em *EdgeManager) serveConn(ctx context.Context, conn *Connection) {
 	em.state.closeConnection(conn)
 }
 
-func (em *EdgeManager) dialEdge(ctx context.Context, edgeIP *net.TCPAddr) (*tls.Conn, error) {
-	timeout := em.state.getConfigurable().Timeout
-	// Inherit from parent context so we can cancel (Ctrl-C) while dialing
-	dialCtx, dialCancel := context.WithTimeout(ctx, timeout)
-	defer dialCancel()
-
-	dialer := net.Dialer{}
-	edgeConn, err := dialer.DialContext(dialCtx, "tcp", edgeIP.String())
-	if err != nil {
-		return nil, dialError{cause: errors.Wrap(err, "DialContext error")}
-	}
-	tlsEdgeConn := tls.Client(edgeConn, em.tlsConfig)
-	tlsEdgeConn.SetDeadline(time.Now().Add(timeout))
-
-	if err = tlsEdgeConn.Handshake(); err != nil {
-		return nil, dialError{cause: errors.Wrap(err, "Handshake with edge error")}
-	}
-	// clear the deadline on the conn; h2mux has its own timeouts
-	tlsEdgeConn.SetDeadline(time.Time{})
-	return tlsEdgeConn, nil
-}
-
 func (em *EdgeManager) noRetryMessage() string {
 	messageTemplate := "cloudflared could not register an Argo Tunnel on your account. Please confirm the following before trying again:" +
 		"1. You have Argo Smart Routing enabled in your account, See Enable Argo section of %s." +