Add a timeout around the upstream dialer. Default is 30 seconds.

config.go

@@ -18,6 +18,7 @@ type Config struct {
 	StripProxyHeaders    bool `json:"strip_proxy_headers"`
 	Port                 int
 	UseIncomingLocalAddr bool `json:"use_incoming_local_addr"`
+	DialTimeout          int
 }
 
 func (config *Config) AuthenticationRequired() bool {

connection.go

@@ -10,6 +10,7 @@ import (
 	"net"
 	"net/http"
 	"strings"
+	"time"
 )
 
 const ProxyAuthenticationRequired = "HTTP/1.0 407 Proxy authentication required\r\n\r\n"
@@ -23,6 +24,8 @@ type connection struct {
 }
 
 func (c *connection) Dial(network, address string) (net.Conn, error) {
+	timeout := time.Second * time.Duration(config.DialTimeout)
+
 	if config.UseIncomingLocalAddr {
 		if c.localAddr == nil {
 			logger.Warn.Println(c.id, "Missing local net.Addr: a default local net.Addr will be used")
@@ -39,7 +42,10 @@ func (c *connection) Dial(network, address string) (net.Conn, error) {
 			goto fallback
 		}
 
-		dialer := &net.Dialer{LocalAddr: c.localAddr}
+		dialer := &net.Dialer{
+			LocalAddr: c.localAddr,
+			Timeout:   timeout,
+		}
 
 		// Try to dial with the incoming LocalAddr to keep the incoming and outgoing IPs the same.
 		conn, err := dialer.Dial(network, address)
@@ -54,7 +60,7 @@ func (c *connection) Dial(network, address string) (net.Conn, error) {
 	}
 
 fallback:
-	return net.Dial(network, address)
+	return net.DialTimeout(network, address, timeout)
 }
 
 func (c *connection) Handle() {

main.go

@@ -53,7 +53,8 @@ func main() {
 	configPtr := flag.String("config", "", "config file")
 	portPtr := flag.Int("port", 25000, "listen port")
 	stripProxyHeadersPtr := flag.Bool("strip-proxy-headers", true, "strip proxy headers from http requests")
-	useIncomingLocalAddr := flag.Bool("use-incoming-local-addr", true, "Attempt to use the local address of the incoming connection when connecting upstream")
+	useIncomingLocalAddr := flag.Bool("use-incoming-local-addr", true, "attempt to use the local address of the incoming connection when connecting upstream")
+	dialTimeoutPtr := flag.Int("dial-timeout", 30, " timeout for connecting to an upstream server in seconds")
 	usernamePtr := flag.String("username", "", "username for proxy authentication")
 	passwordPtr := flag.String("password", "", "password for proxy authentication")
 	flag.Parse()
@@ -77,6 +78,7 @@ func main() {
 			Port:                 *portPtr,
 			StripProxyHeaders:    *stripProxyHeadersPtr,
 			UseIncomingLocalAddr: *useIncomingLocalAddr,
+			DialTimeout:          *dialTimeoutPtr,
 		}
 
 		if *usernamePtr != "" {