proxy: split SOCKS5 Dial method in two
Split off a new SOCKS5 connect() method from Dial.
connect() takes an existing connection to a socks5 server, and
commands the server to extend that connection to a given target
address and port.
Change-Id: I5dbba58a67a0d884bda3d3ac194dc18bdebe74ab
Reviewed-on: https://go-review.googlesource.com/36643
Reviewed-by: Adam Langley <agl@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/proxy/socks5.go b/proxy/socks5.go
index 9b96282..973f57f 100644
--- a/proxy/socks5.go
+++ b/proxy/socks5.go
@@ -72,24 +72,28 @@
if err != nil {
return nil, err
}
- closeConn := &conn
- defer func() {
- if closeConn != nil {
- (*closeConn).Close()
- }
- }()
-
- host, portStr, err := net.SplitHostPort(addr)
- if err != nil {
+ if err := s.connect(conn, addr); err != nil {
+ conn.Close()
return nil, err
}
+ return conn, nil
+}
+
+// connect takes an existing connection to a socks5 proxy server,
+// and commands the server to extend that connection to target,
+// which must be a canonical address with a host and port.
+func (s *socks5) connect(conn net.Conn, target string) error {
+ host, portStr, err := net.SplitHostPort(target)
+ if err != nil {
+ return err
+ }
port, err := strconv.Atoi(portStr)
if err != nil {
- return nil, errors.New("proxy: failed to parse port number: " + portStr)
+ return errors.New("proxy: failed to parse port number: " + portStr)
}
if port < 1 || port > 0xffff {
- return nil, errors.New("proxy: port number out of range: " + portStr)
+ return errors.New("proxy: port number out of range: " + portStr)
}
// the size here is just an estimate
@@ -103,17 +107,17 @@
}
if _, err := conn.Write(buf); err != nil {
- return nil, errors.New("proxy: failed to write greeting to SOCKS5 proxy at " + s.addr + ": " + err.Error())
+ return errors.New("proxy: failed to write greeting to SOCKS5 proxy at " + s.addr + ": " + err.Error())
}
if _, err := io.ReadFull(conn, buf[:2]); err != nil {
- return nil, errors.New("proxy: failed to read greeting from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+ return errors.New("proxy: failed to read greeting from SOCKS5 proxy at " + s.addr + ": " + err.Error())
}
if buf[0] != 5 {
- return nil, errors.New("proxy: SOCKS5 proxy at " + s.addr + " has unexpected version " + strconv.Itoa(int(buf[0])))
+ return errors.New("proxy: SOCKS5 proxy at " + s.addr + " has unexpected version " + strconv.Itoa(int(buf[0])))
}
if buf[1] == 0xff {
- return nil, errors.New("proxy: SOCKS5 proxy at " + s.addr + " requires authentication")
+ return errors.New("proxy: SOCKS5 proxy at " + s.addr + " requires authentication")
}
if buf[1] == socks5AuthPassword {
@@ -125,15 +129,15 @@
buf = append(buf, s.password...)
if _, err := conn.Write(buf); err != nil {
- return nil, errors.New("proxy: failed to write authentication request to SOCKS5 proxy at " + s.addr + ": " + err.Error())
+ return errors.New("proxy: failed to write authentication request to SOCKS5 proxy at " + s.addr + ": " + err.Error())
}
if _, err := io.ReadFull(conn, buf[:2]); err != nil {
- return nil, errors.New("proxy: failed to read authentication reply from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+ return errors.New("proxy: failed to read authentication reply from SOCKS5 proxy at " + s.addr + ": " + err.Error())
}
if buf[1] != 0 {
- return nil, errors.New("proxy: SOCKS5 proxy at " + s.addr + " rejected username/password")
+ return errors.New("proxy: SOCKS5 proxy at " + s.addr + " rejected username/password")
}
}
@@ -150,7 +154,7 @@
buf = append(buf, ip...)
} else {
if len(host) > 255 {
- return nil, errors.New("proxy: destination hostname too long: " + host)
+ return errors.New("proxy: destination hostname too long: " + host)
}
buf = append(buf, socks5Domain)
buf = append(buf, byte(len(host)))
@@ -159,11 +163,11 @@
buf = append(buf, byte(port>>8), byte(port))
if _, err := conn.Write(buf); err != nil {
- return nil, errors.New("proxy: failed to write connect request to SOCKS5 proxy at " + s.addr + ": " + err.Error())
+ return errors.New("proxy: failed to write connect request to SOCKS5 proxy at " + s.addr + ": " + err.Error())
}
if _, err := io.ReadFull(conn, buf[:4]); err != nil {
- return nil, errors.New("proxy: failed to read connect reply from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+ return errors.New("proxy: failed to read connect reply from SOCKS5 proxy at " + s.addr + ": " + err.Error())
}
failure := "unknown error"
@@ -172,7 +176,7 @@
}
if len(failure) > 0 {
- return nil, errors.New("proxy: SOCKS5 proxy at " + s.addr + " failed to connect: " + failure)
+ return errors.New("proxy: SOCKS5 proxy at " + s.addr + " failed to connect: " + failure)
}
bytesToDiscard := 0
@@ -184,11 +188,11 @@
case socks5Domain:
_, err := io.ReadFull(conn, buf[:1])
if err != nil {
- return nil, errors.New("proxy: failed to read domain length from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+ return errors.New("proxy: failed to read domain length from SOCKS5 proxy at " + s.addr + ": " + err.Error())
}
bytesToDiscard = int(buf[0])
default:
- return nil, errors.New("proxy: got unknown address type " + strconv.Itoa(int(buf[3])) + " from SOCKS5 proxy at " + s.addr)
+ return errors.New("proxy: got unknown address type " + strconv.Itoa(int(buf[3])) + " from SOCKS5 proxy at " + s.addr)
}
if cap(buf) < bytesToDiscard {
@@ -197,14 +201,13 @@
buf = buf[:bytesToDiscard]
}
if _, err := io.ReadFull(conn, buf); err != nil {
- return nil, errors.New("proxy: failed to read address from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+ return errors.New("proxy: failed to read address from SOCKS5 proxy at " + s.addr + ": " + err.Error())
}
// Also need to discard the port number
if _, err := io.ReadFull(conn, buf[:2]); err != nil {
- return nil, errors.New("proxy: failed to read port from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+ return errors.New("proxy: failed to read port from SOCKS5 proxy at " + s.addr + ": " + err.Error())
}
- closeConn = nil
- return conn, nil
+ return nil
}
