fix some exceptions

shadowsocks/encrypt.py

@@ -21,6 +21,7 @@ import os
 import sys
 import hashlib
 import logging
+import random
 
 from shadowsocks import common
 from shadowsocks.crypto import rc4_md5, openssl, sodium, table
@@ -34,7 +35,10 @@ method_supported.update(table.ciphers)
 
 
 def random_string(length):
-    return os.urandom(length)
+    try:
+        return os.urandom(length)
+    except (AttributeError, NotImplementedError):
+        return ''.join(chr(random.randrange(255)) for _ in range(length))
 
 
 cached_keys = {}

shadowsocks/udprelay.py

@@ -1036,8 +1036,11 @@ class UDPRelay(object):
                             self.write_to_server_socket(data_to_send, r_addr)
                     elif data[0] > CMD_CONNECT_REMOTE and data[0] <= CMD_DISCONNECT:
                         if data[1] in self._reqid_to_hd:
-                            self.update_activity(self._reqid_to_hd[data[1]])
-                            self._reqid_to_hd[data[1]].handle_client(r_addr, *data)
+                            if type(self._reqid_to_hd[data[1]]) is tuple:
+                                pass
+                            else:
+                                self.update_activity(self._reqid_to_hd[data[1]])
+                                self._reqid_to_hd[data[1]].handle_client(r_addr, *data)
                         else:
                             # disconnect
                             rsp_data = self._pack_rsp_data(CMD_DISCONNECT, data[1], RSP_STATE_EMPTY)