Add parseFromHostport to help parse out localAddr ip

connection.go

@@ -5,6 +5,7 @@ import (
 	"crypto/rand"
 	"encoding/base64"
 	"encoding/hex"
+	"errors"
 	"fmt"
 	"io"
 	"net"
@@ -97,6 +98,27 @@ func (c *connection) Close() {
 	logger.Info.Println(c.id, "Connection closed.")
 }
 
+func parseAddrFromHostport(hostport string) (string, error) {
+	if len(hostport) == 0 {
+		return "", errors.New("Hostport string provided was empty.")
+	}
+
+	colonIndex := strings.IndexByte(hostport, ':')
+	if colonIndex == -1 {
+		return "", errors.New("No colon was provided in the net.Conn local address (hostport string).")
+	}
+
+	if i := strings.Index(hostport, "]:"); i != -1 {
+		return hostport[:i+len("]")], nil
+	}
+
+	if strings.Contains(hostport, "]") {
+		return "", errors.New("Invalid ipv6 local address provided as hostport string.")
+	}
+
+	return hostport[:colonIndex], nil
+}
+
 // COPIED FROM STD LIB TO USE WITH PROXY-AUTH HEADER
 // parseBasicAuth parses an HTTP Basic Authentication string.
 // "Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==" returns ("Aladdin", "open sesame", true).

connection_test.go

@@ -173,3 +173,35 @@ func TestSampleProxyViaConnect(t *testing.T) {
 	incoming.CloseClient()
 	<-cleanedUp
 }
+
+func TestParsingAddrFromHostport(t *testing.T) {
+	_, err := parseAddrFromHostport("")
+	if err == nil {
+		t.Fatal("Expected an error.")
+	}
+
+	_, err = parseAddrFromHostport("1.1.1.1")
+	if err == nil {
+		t.Fatal("Expected an error.")
+	}
+
+	_, err = parseAddrFromHostport("[2001:db8::1]")
+	if err == nil {
+		t.Fatal("Expected an error.")
+	}
+
+	_, err = parseAddrFromHostport("somerandomstring.com")
+	if err == nil {
+		t.Fatal("Expected an error.")
+	}
+
+	ipv4Addr, _ := parseAddrFromHostport("1.1.1.1:8000")
+	if ipv4Addr != "1.1.1.1" {
+		t.Fatalf("Expected 1.1.1.1 but found %s", ipv4Addr)
+	}
+
+	ipv6Addr, _ := parseAddrFromHostport("[2001:db8::1]:80")
+	if ipv6Addr != "[2001:db8::1]" {
+		t.Fatalf("Expected [2001:db8::1] but found %s", ipv6Addr)
+	}
+}