fix a potential RST problem

shadowsocks/local.py

@@ -100,6 +100,7 @@ class Socks5Server(SocketServer.StreamRequestHandler):
             else:
                 fdset = [sock, remote]
             while True:
+                should_break = False
                 r, w, e = select.select(fdset, [], [])
                 if sock in r:
                     if not connected and config_fast_open:
@@ -123,7 +124,8 @@ class Socks5Server(SocketServer.StreamRequestHandler):
                             pending_data = None
                         data = encryptor.encrypt(data)
                         if len(data) <= 0:
-                            break
+                            should_break = True
+                        else:
                             result = send_all(remote, data)
                             if result < len(data):
                                 raise Exception('failed to send all data')
@@ -131,10 +133,16 @@ class Socks5Server(SocketServer.StreamRequestHandler):
                 if remote in r:
                     data = encryptor.decrypt(remote.recv(4096))
                     if len(data) <= 0:
-                        break
+                        should_break = True
+                    else:
                         result = send_all(sock, data)
                         if result < len(data):
                             raise Exception('failed to send all data')
+                if should_break:
+                    # make sure all data are read before we close the sockets
+                    # TODO: we haven't read ALL the data, actually
+                    # http://cs.ecs.baylor.edu/~donahoo/practical/CSockets/TCPRST.pdf
+                    break
         finally:
             sock.close()
             remote.close()

shadowsocks/server.py

@@ -79,21 +79,29 @@ class Socks5Server(SocketServer.StreamRequestHandler):
         try:
             fdset = [sock, remote]
             while True:
+                should_break = False
                 r, w, e = select.select(fdset, [], [])
                 if sock in r:
                     data = self.decrypt(sock.recv(4096))
                     if len(data) <= 0:
-                        break
+                        should_break = True
+                    else:
                         result = send_all(remote, data)
                         if result < len(data):
                             raise Exception('failed to send all data')
                 if remote in r:
                     data = self.encrypt(remote.recv(4096))
                     if len(data) <= 0:
-                        break
+                        should_break = True
+                    else:
                         result = send_all(sock, data)
                         if result < len(data):
                             raise Exception('failed to send all data')
+                if should_break:
+                    # make sure all data are read before we close the sockets
+                    # TODO: we haven't read ALL the data, actually
+                    # http://cs.ecs.baylor.edu/~donahoo/practical/CSockets/TCPRST.pdf
+                    break
 
         finally:
             sock.close()