add verify_sha1 (libev OTA)

shadowsocks/obfs.py

@@ -23,13 +23,14 @@ import hashlib
 import logging
 
 from shadowsocks import common
-from shadowsocks.obfsplugin import plain, http_simple, verify_simple
+from shadowsocks.obfsplugin import plain, http_simple, verify, auth
 
 
 method_supported = {}
 method_supported.update(plain.obfs_map)
 method_supported.update(http_simple.obfs_map)
-method_supported.update(verify_simple.obfs_map)
+method_supported.update(verify.obfs_map)
+method_supported.update(auth.obfs_map)
 
 class server_info(object):
     def __init__(self, data):

shadowsocks/obfsplugin/auth.py

@@ -0,0 +1,326 @@
+#!/usr/bin/env python
+#
+# Copyright 2015-2015 breakwa11
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+from __future__ import absolute_import, division, print_function, \
+    with_statement
+
+import os
+import sys
+import hashlib
+import logging
+import binascii
+import base64
+import time
+import datetime
+import random
+import struct
+import zlib
+import hmac
+import hashlib
+
+import shadowsocks
+from shadowsocks import common
+from shadowsocks.obfsplugin import plain
+from shadowsocks.common import to_bytes, to_str, ord, chr
+
+def create_auth_obfs(method):
+    return auth_simple(method)
+
+obfs_map = {
+        'auth_simple': (create_auth_obfs,),
+}
+
+def match_begin(str1, str2):
+    if len(str1) >= len(str2):
+        if str1[:len(str2)] == str2:
+            return True
+    return False
+
+class obfs_verify_data(object):
+    def __init__(self):
+        pass
+
+class verify_base(plain.plain):
+    def __init__(self, method):
+        super(verify_base, self).__init__(method)
+        self.method = method
+
+    def init_data(self):
+        return ''
+
+    def set_server_info(self, server_info):
+        self.server_info = server_info
+
+    def client_encode(self, buf):
+        return buf
+
+    def client_decode(self, buf):
+        return (buf, False)
+
+    def server_encode(self, buf):
+        return buf
+
+    def server_decode(self, buf):
+        return (buf, True, False)
+
+class client_queue(object):
+    def __init__(self, begin_id):
+        self.front = begin_id
+        self.back = begin_id
+        self.alloc = {}
+        self.enable = True
+        self.last_update = time.time()
+
+    def update(self):
+        self.last_update = time.time()
+
+    def is_active(self):
+        return time.time() - self.last_update < 60 * 3
+
+    def re_enable(self, connection_id):
+        self.enable = True
+        self.alloc = {}
+        self.front = connection_id
+        self.back = connection_id
+
+    def insert(self, connection_id):
+        self.update()
+        if not self.enable:
+            logging.warn('auth_simple: not enable')
+            return False
+        if connection_id < self.front:
+            logging.warn('auth_simple: duplicate id')
+            return False
+        if not self.is_active():
+            self.re_enable(connection_id)
+        if connection_id > self.front + 0x4000:
+            logging.warn('auth_simple: wrong id')
+            return False
+        if connection_id in self.alloc:
+            logging.warn('auth_simple: duplicate id 2')
+            return False
+        if self.back <= connection_id:
+            self.back = connection_id + 1
+        self.alloc[connection_id] = 1
+        while (self.front in self.alloc) or self.front + 0x1000 < self.back:
+            if self.front in self.alloc:
+                del self.alloc[self.front]
+            self.front += 1
+        return True
+
+class obfs_auth_data(object):
+    def __init__(self):
+        self.client_id = {}
+        self.startup_time = int(time.time() - 30) & 0xFFFFFFFF
+        self.local_client_id = b''
+        self.connection_id = 0
+        self.max_client = 16                         # max active client count
+        self.max_buffer = max(self.max_client, 256)  # max client id buffer size
+
+    def update(self, client_id, connection_id):
+        if client_id in self.client_id:
+            self.client_id[client_id].update()
+
+    def insert(self, client_id, connection_id):
+        if client_id not in self.client_id or not self.client_id[client_id].enable:
+            active = 0
+            for c_id in self.client_id:
+                if self.client_id[c_id].is_active():
+                    active += 1
+            if active >= self.max_client:
+                logging.warn('auth_simple: max active clients exceeded')
+                return False
+
+            if len(self.client_id) < self.max_client:
+                if client_id not in self.client_id:
+                    self.client_id[client_id] = client_queue(connection_id)
+                else:
+                    self.client_id[client_id].re_enable(connection_id)
+                return self.client_id[client_id].insert(connection_id)
+            keys = self.client_id.keys()
+            random.shuffle(keys)
+            for c_id in keys:
+                if not self.client_id[c_id].is_active() and self.client_id[c_id].enable:
+                    if len(self.client_id) >= self.max_buffer:
+                        del self.client_id[c_id]
+                    else:
+                        self.client_id[c_id].enable = False
+                    if client_id not in self.client_id:
+                        self.client_id[client_id] = client_queue(connection_id)
+                    else:
+                        self.client_id[client_id].re_enable(connection_id)
+                    return self.client_id[client_id].insert(connection_id)
+            logging.warn('auth_simple: no inactive client [assert]')
+            return False
+        else:
+            return self.client_id[client_id].insert(connection_id)
+
+class auth_simple(verify_base):
+    def __init__(self, method):
+        super(auth_simple, self).__init__(method)
+        self.recv_buf = b''
+        self.unit_len = 8100
+        self.decrypt_packet_num = 0
+        self.raw_trans = False
+        self.has_sent_header = False
+        self.has_recv_header = False
+        self.client_id = 0
+        self.connection_id = 0
+        self.max_time_dif = 60 * 5 # time dif (second) setting
+
+    def init_data(self):
+        return obfs_auth_data()
+
+    def pack_data(self, buf):
+        if len(buf) == 0:
+            return b''
+        rnd_data = os.urandom(common.ord(os.urandom(1)[0]) % 16)
+        data = common.chr(len(rnd_data) + 1) + rnd_data + buf
+        data = struct.pack('>H', len(data) + 6) + data
+        crc = (0xffffffff - binascii.crc32(data)) & 0xffffffff
+        data += struct.pack('<I', crc)
+        return data
+
+    def auth_data(self):
+        utc_time = int(time.time()) & 0xFFFFFFFF
+        if self.server_info.data.connection_id > 0xFF000000:
+            self.server_info.data.local_client_id = b''
+        if not self.server_info.data.local_client_id:
+            self.server_info.data.local_client_id = os.urandom(4)
+            logging.debug("local_client_id %s" % (binascii.hexlify(self.server_info.data.local_client_id),))
+            self.server_info.data.connection_id = struct.unpack('<I', os.urandom(4))[0] & 0xFFFFFF
+        self.server_info.data.connection_id += 1
+        return b''.join([struct.pack('<I', utc_time),
+                self.server_info.data.local_client_id,
+                struct.pack('<I', self.server_info.data.connection_id)])
+
+    def client_pre_encrypt(self, buf):
+        ret = b''
+        if not self.has_sent_header:
+            head_size = self.get_head_size(buf, 30)
+            datalen = min(len(buf), random.randint(0, 31) + head_size)
+            ret += self.pack_data(self.auth_data() + buf[:datalen])
+            buf = buf[datalen:]
+            self.has_sent_header = True
+        while len(buf) > self.unit_len:
+            ret += self.pack_data(buf[:self.unit_len])
+            buf = buf[self.unit_len:]
+        ret += self.pack_data(buf)
+        return ret
+
+    def client_post_decrypt(self, buf):
+        if self.raw_trans:
+            return buf
+        self.recv_buf += buf
+        out_buf = b''
+        while len(self.recv_buf) > 2:
+            length = struct.unpack('>H', self.recv_buf[:2])[0]
+            if length >= 8192 or length < 7:
+                self.raw_trans = True
+                self.recv_buf = b''
+                if self.decrypt_packet_num == 0:
+                    return None
+                else:
+                    raise Exception('server_post_decrype data error')
+            if length > len(self.recv_buf):
+                break
+
+            if (binascii.crc32(self.recv_buf[:length]) & 0xffffffff) != 0xffffffff:
+                self.raw_trans = True
+                self.recv_buf = b''
+                if self.decrypt_packet_num == 0:
+                    return None
+                else:
+                    raise Exception('server_post_decrype data uncorrect CRC32')
+
+            pos = common.ord(self.recv_buf[2]) + 2
+            out_buf += self.recv_buf[pos:length - 4]
+            self.recv_buf = self.recv_buf[length:]
+
+        if out_buf:
+            self.decrypt_packet_num += 1
+        return out_buf
+
+    def server_pre_encrypt(self, buf):
+        ret = b''
+        while len(buf) > self.unit_len:
+            ret += self.pack_data(buf[:self.unit_len])
+            buf = buf[self.unit_len:]
+        ret += self.pack_data(buf)
+        return ret
+
+    def server_post_decrypt(self, buf):
+        if self.raw_trans:
+            return buf
+        self.recv_buf += buf
+        out_buf = b''
+        while len(self.recv_buf) > 2:
+            length = struct.unpack('>H', self.recv_buf[:2])[0]
+            if length >= 8192 or length < 7:
+                self.raw_trans = True
+                self.recv_buf = b''
+                if self.decrypt_packet_num == 0:
+                    logging.info('auth_simple: over size')
+                    return b'E'
+                else:
+                    raise Exception('server_post_decrype data error')
+            if length > len(self.recv_buf):
+                break
+
+            if (binascii.crc32(self.recv_buf[:length]) & 0xffffffff) != 0xffffffff:
+                logging.info('auth_simple: crc32 error, data %s' % (binascii.hexlify(self.recv_buf[:length]),))
+                self.raw_trans = True
+                self.recv_buf = b''
+                if self.decrypt_packet_num == 0:
+                    return b'E'
+                else:
+                    raise Exception('server_post_decrype data uncorrect CRC32')
+
+            pos = common.ord(self.recv_buf[2]) + 2
+            out_buf += self.recv_buf[pos:length - 4]
+            if not self.has_recv_header:
+                if len(out_buf) < 12:
+                    self.raw_trans = True
+                    self.recv_buf = b''
+                    logging.info('auth_simple: too short')
+                    return b'E'
+                utc_time = struct.unpack('<I', out_buf[:4])[0]
+                client_id = struct.unpack('<I', out_buf[4:8])[0]
+                connection_id = struct.unpack('<I', out_buf[8:12])[0]
+                time_dif = common.int32((int(time.time()) & 0xffffffff) - utc_time)
+                if time_dif < -self.max_time_dif or time_dif > self.max_time_dif \
+                        or common.int32(utc_time - self.server_info.data.startup_time) < 0:
+                    self.raw_trans = True
+                    self.recv_buf = b''
+                    logging.info('auth_simple: wrong timestamp, time_dif %d, data %s' % (time_dif, binascii.hexlify(out_buf),))
+                    return b'E'
+                elif self.server_info.data.insert(client_id, connection_id):
+                    self.has_recv_header = True
+                    out_buf = out_buf[12:]
+                    self.client_id = client_id
+                    self.connection_id = connection_id
+                else:
+                    self.raw_trans = True
+                    self.recv_buf = b''
+                    logging.info('auth_simple: auth fail, data %s' % (binascii.hexlify(out_buf),))
+                    return b'E'
+            self.recv_buf = self.recv_buf[length:]
+
+        if out_buf:
+            self.server_info.data.update(self.client_id, self.connection_id)
+            self.decrypt_packet_num += 1
+        return out_buf
+

shadowsocks/obfsplugin/verify_simple.py

@@ -28,11 +28,13 @@ import datetime
 import random
 import struct
 import zlib
+import hmac
+import hashlib
 
 import shadowsocks
 from shadowsocks import common
 from shadowsocks.obfsplugin import plain
-from shadowsocks.common import to_bytes, to_str, ord
+from shadowsocks.common import to_bytes, to_str, ord, chr
 
 def create_verify_obfs(method):
     return verify_simple(method)
@@ -40,13 +42,17 @@ def create_verify_obfs(method):
 def create_verify_deflate(method):
     return verify_deflate(method)
 
+def create_verify_sha1(method):
+    return verify_sha1(method)
+
 def create_auth_obfs(method):
     return auth_simple(method)
 
 obfs_map = {
         'verify_simple': (create_verify_obfs,),
         'verify_deflate': (create_verify_deflate,),
-        'auth_simple': (create_auth_obfs,),
+        'verify_sha1': (create_verify_sha1,),
+        'verify_sha1_compatible': (create_verify_sha1,),
 }
 
 def match_begin(str1, str2):
@@ -261,143 +267,35 @@ class verify_deflate(verify_base):
             self.decrypt_packet_num += 1
         return out_buf
 
-class client_queue(object):
+class verify_sha1(verify_base):
-    def __init__(self, begin_id):
-        self.front = begin_id
-        self.back = begin_id
-        self.alloc = {}
-        self.enable = True
-        self.last_update = time.time()
-
-    def update(self):
-        self.last_update = time.time()
-
-    def is_active(self):
-        return time.time() - self.last_update < 60 * 3
-
-    def re_enable(self, connection_id):
-        self.enable = True
-        self.alloc = {}
-        self.front = connection_id
-        self.back = connection_id
-
-    def insert(self, connection_id):
-        self.update()
-        if not self.enable:
-            logging.warn('auth_simple: not enable')
-            return False
-        if connection_id < self.front:
-            logging.warn('auth_simple: duplicate id')
-            return False
-        if not self.is_active():
-            self.re_enable(connection_id)
-        if connection_id > self.front + 0x4000:
-            logging.warn('auth_simple: wrong id')
-            return False
-        if connection_id in self.alloc:
-            logging.warn('auth_simple: duplicate id 2')
-            return False
-        if self.back <= connection_id:
-            self.back = connection_id + 1
-        self.alloc[connection_id] = 1
-        while (self.front in self.alloc) or self.front + 0x1000 < self.back:
-            if self.front in self.alloc:
-                del self.alloc[self.front]
-            self.front += 1
-        return True
-
-class obfs_auth_data(object):
-    def __init__(self):
-        self.client_id = {}
-        self.startup_time = int(time.time() - 30) & 0xFFFFFFFF
-        self.local_client_id = b''
-        self.connection_id = 0
-        self.max_client = 16                         # max active client count
-        self.max_buffer = max(self.max_client, 256)  # max client id buffer size
-
-    def update(self, client_id, connection_id):
-        if client_id in self.client_id:
-            self.client_id[client_id].update()
-
-    def insert(self, client_id, connection_id):
-        if client_id not in self.client_id or not self.client_id[client_id].enable:
-            active = 0
-            for c_id in self.client_id:
-                if self.client_id[c_id].is_active():
-                    active += 1
-            if active >= self.max_client:
-                logging.warn('auth_simple: max active clients exceeded')
-                return False
-
-            if len(self.client_id) < self.max_client:
-                if client_id not in self.client_id:
-                    self.client_id[client_id] = client_queue(connection_id)
-                else:
-                    self.client_id[client_id].re_enable(connection_id)
-                return self.client_id[client_id].insert(connection_id)
-            keys = self.client_id.keys()
-            random.shuffle(keys)
-            for c_id in keys:
-                if not self.client_id[c_id].is_active() and self.client_id[c_id].enable:
-                    if len(self.client_id) >= self.max_buffer:
-                        del self.client_id[c_id]
-                    else:
-                        self.client_id[c_id].enable = False
-                    if client_id not in self.client_id:
-                        self.client_id[client_id] = client_queue(connection_id)
-                    else:
-                        self.client_id[client_id].re_enable(connection_id)
-                    return self.client_id[client_id].insert(connection_id)
-            logging.warn('auth_simple: no inactive client [assert]')
-            return False
-        else:
-            return self.client_id[client_id].insert(connection_id)
-
-class auth_simple(verify_base):
     def __init__(self, method):
-        super(auth_simple, self).__init__(method)
+        super(verify_sha1, self).__init__(method)
         self.recv_buf = b''
         self.unit_len = 8100
-        self.decrypt_packet_num = 0
         self.raw_trans = False
+        self.pack_id = 0
+        self.recv_id = 0
         self.has_sent_header = False
         self.has_recv_header = False
-        self.client_id = 0
-        self.connection_id = 0
-        self.max_time_dif = 60 * 5 # time dif (second) setting
-
-    def init_data(self):
-        return obfs_auth_data()
 
     def pack_data(self, buf):
         if len(buf) == 0:
             return b''
-        rnd_data = os.urandom(common.ord(os.urandom(1)[0]) % 16)
+        sha1data = hmac.new(self.server_info.iv + struct.pack('>I', self.pack_id), buf, hashlib.sha1).digest()
-        data = common.chr(len(rnd_data) + 1) + rnd_data + buf
+        data = struct.pack('>H', len(buf)) + sha1data[:10] + buf
-        data = struct.pack('>H', len(data) + 6) + data
+        self.pack_id += 1
-        crc = (0xffffffff - binascii.crc32(data)) & 0xffffffff
-        data += struct.pack('<I', crc)
         return data
 
-    def auth_data(self):
+    def auth_pack_data(self, buf):
-        utc_time = int(time.time()) & 0xFFFFFFFF
+        data = buf
-        if self.server_info.data.connection_id > 0xFF000000:
+        data += hmac.new(self.server_info.iv + self.server_info.key, buf, hashlib.sha1).digest()[:10]
-            self.server_info.data.local_client_id = b''
+        return data
-        if not self.server_info.data.local_client_id:
-            self.server_info.data.local_client_id = os.urandom(4)
-            logging.debug("local_client_id %s" % (binascii.hexlify(self.server_info.data.local_client_id),))
-            self.server_info.data.connection_id = struct.unpack('<I', os.urandom(4))[0] & 0xFFFFFF
-        self.server_info.data.connection_id += 1
-        return b''.join([struct.pack('<I', utc_time),
-                self.server_info.data.local_client_id,
-                struct.pack('<I', self.server_info.data.connection_id)])
 
     def client_pre_encrypt(self, buf):
         ret = b''
         if not self.has_sent_header:
-            head_size = self.get_head_size(buf, 30)
+            datalen = self.get_head_size(buf, 30)
-            datalen = min(len(buf), random.randint(0, 31) + head_size)
+            ret += self.auth_pack_data(buf[datalen:])
-            ret += self.pack_data(self.auth_data() + buf[:datalen])
             buf = buf[datalen:]
             self.has_sent_header = True
         while len(buf) > self.unit_len:
@@ -407,105 +305,49 @@ class auth_simple(verify_base):
         return ret
 
     def client_post_decrypt(self, buf):
-        if self.raw_trans:
+        return buf
-            return buf
-        self.recv_buf += buf
-        out_buf = b''
-        while len(self.recv_buf) > 2:
-            length = struct.unpack('>H', self.recv_buf[:2])[0]
-            if length >= 8192 or length < 7:
-                self.raw_trans = True
-                self.recv_buf = b''
-                if self.decrypt_packet_num == 0:
-                    return None
-                else:
-                    raise Exception('server_post_decrype data error')
-            if length > len(self.recv_buf):
-                break
-
-            if (binascii.crc32(self.recv_buf[:length]) & 0xffffffff) != 0xffffffff:
-                self.raw_trans = True
-                self.recv_buf = b''
-                if self.decrypt_packet_num == 0:
-                    return None
-                else:
-                    raise Exception('server_post_decrype data uncorrect CRC32')
-
-            pos = common.ord(self.recv_buf[2]) + 2
-            out_buf += self.recv_buf[pos:length - 4]
-            self.recv_buf = self.recv_buf[length:]
-
-        if out_buf:
-            self.decrypt_packet_num += 1
-        return out_buf
 
     def server_pre_encrypt(self, buf):
-        ret = b''
+        return buf
-        while len(buf) > self.unit_len:
-            ret += self.pack_data(buf[:self.unit_len])
-            buf = buf[self.unit_len:]
-        ret += self.pack_data(buf)
-        return ret
 
     def server_post_decrypt(self, buf):
         if self.raw_trans:
             return buf
         self.recv_buf += buf
         out_buf = b''
-        while len(self.recv_buf) > 2:
+        if not self.has_recv_header:
-            length = struct.unpack('>H', self.recv_buf[:2])[0]
+            if len(self.recv_buf) < 2:
-            if length >= 8192 or length < 7:
+                return b''
-                self.raw_trans = True
+            if (ord(self.recv_buf[0]) & 0x10) != 0x10:
-                self.recv_buf = b''
+                if self.method == 'verify_sha1':
-                if self.decrypt_packet_num == 0:
+                    logging.error('Not One-time authentication header')
-                    logging.info('auth_simple: over size')
                     return b'E'
                 else:
-                    raise Exception('server_post_decrype data error')
+                    self.raw_trans = True
+                    return self.recv_buf
+            head_size = self.get_head_size(self.recv_buf, 30)
+            if len(self.recv_buf) < head_size + 10:
+                return b''
+            sha1data = hmac.new(self.server_info.recv_iv + self.server_info.key, self.recv_buf[:head_size], hashlib.sha1).digest()[:10]
+            if sha1data != self.recv_buf[head_size:head_size + 10]:
+                logging.error('server_post_decrype data uncorrect auth HMAC-SHA1')
+                return b'E'
+            out_buf = to_bytes(chr(ord(self.recv_buf[0]) & 0xF)) + self.recv_buf[1:head_size]
+            self.recv_buf = self.recv_buf[head_size + 10:]
+            self.has_recv_header = True
+        while len(self.recv_buf) > 2:
+            length = struct.unpack('>H', self.recv_buf[:2])[0] + 12
             if length > len(self.recv_buf):
                 break
 
-            if (binascii.crc32(self.recv_buf[:length]) & 0xffffffff) != 0xffffffff:
+            data = self.recv_buf[12:length]
-                logging.info('auth_simple: crc32 error, data %s' % (binascii.hexlify(self.recv_buf[:length]),))
+            sha1data = hmac.new(self.server_info.recv_iv + struct.pack('>I', self.recv_id), data, hashlib.sha1).digest()[:10]
-                self.raw_trans = True
+            if sha1data != self.recv_buf[2:12]:
-                self.recv_buf = b''
+                raise Exception('server_post_decrype data uncorrect chunk HMAC-SHA1')
-                if self.decrypt_packet_num == 0:
-                    return b'E'
-                else:
-                    raise Exception('server_post_decrype data uncorrect CRC32')
 
-            pos = common.ord(self.recv_buf[2]) + 2
+            self.recv_id += 1
-            out_buf += self.recv_buf[pos:length - 4]
+            out_buf += data
-            if not self.has_recv_header:
-                if len(out_buf) < 12:
-                    self.raw_trans = True
-                    self.recv_buf = b''
-                    logging.info('auth_simple: too short')
-                    return b'E'
-                utc_time = struct.unpack('<I', out_buf[:4])[0]
-                client_id = struct.unpack('<I', out_buf[4:8])[0]
-                connection_id = struct.unpack('<I', out_buf[8:12])[0]
-                time_dif = common.int32((int(time.time()) & 0xffffffff) - utc_time)
-                if time_dif < -self.max_time_dif or time_dif > self.max_time_dif \
-                        or common.int32(utc_time - self.server_info.data.startup_time) < 0:
-                    self.raw_trans = True
-                    self.recv_buf = b''
-                    logging.info('auth_simple: wrong timestamp, time_dif %d, data %s' % (time_dif, binascii.hexlify(out_buf),))
-                    return b'E'
-                elif self.server_info.data.insert(client_id, connection_id):
-                    self.has_recv_header = True
-                    out_buf = out_buf[12:]
-                    self.client_id = client_id
-                    self.connection_id = connection_id
-                else:
-                    self.raw_trans = True
-                    self.recv_buf = b''
-                    logging.info('auth_simple: auth fail, data %s' % (binascii.hexlify(out_buf),))
-                    return b'E'
             self.recv_buf = self.recv_buf[length:]
 
-        if out_buf:
-            self.server_info.data.update(self.client_id, self.connection_id)
-            self.decrypt_packet_num += 1
         return out_buf
 

shadowsocks/tcprelay.py

@@ -30,9 +30,6 @@ import random
 from shadowsocks import encrypt, obfs, eventloop, shell, common
 from shadowsocks.common import pre_parse_header, parse_header
 
-# set it 'True' if run as a local client and connect to a server which support new protocol
-CLIENT_NEW_PROTOCOL = False #deprecated
-
 # we clear at most TIMEOUTS_CLEAN_SIZE timeouts each time
 TIMEOUTS_CLEAN_SIZE = 512
 
@@ -120,6 +117,7 @@ class TCPRelayHandler(object):
         server_info.port = server._listen_port
         server_info.param = config['obfs_param']
         server_info.iv = self._encryptor.cipher_iv
+        server_info.recv_iv = b''
         server_info.key = self._encryptor.cipher_key
         server_info.head_len = 30
         server_info.tcp_mss = 1440
@@ -131,6 +129,7 @@ class TCPRelayHandler(object):
         server_info.port = server._listen_port
         server_info.param = ''
         server_info.iv = self._encryptor.cipher_iv
+        server_info.recv_iv = b''
         server_info.key = self._encryptor.cipher_key
         server_info.head_len = 30
         server_info.tcp_mss = 1440
@@ -460,12 +459,6 @@ class TCPRelayHandler(object):
                 head_len = self._get_head_size(data, 30)
                 self._obfs.obfs.server_info.head_len = head_len
                 self._protocol.obfs.server_info.head_len = head_len
-                if CLIENT_NEW_PROTOCOL:
-                    rnd_len = random.randint(1, 32)
-                    total_len = 7 + rnd_len + len(data)
-                    data = b'\x88' + struct.pack('>H', total_len) + chr(rnd_len) + (b' ' * (rnd_len - 1)) + data
-                    crc = (0xffffffff - binascii.crc32(data)) & 0xffffffff
-                    data += struct.pack('<I', crc)
                 if self._encryptor is not None:
                     data = self._protocol.client_pre_encrypt(data)
                     data_to_send = self._encryptor.encrypt(data)
@@ -606,6 +599,9 @@ class TCPRelayHandler(object):
                     if obfs_decode[2]:
                         self._write_to_sock(b'', self._local_sock)
                     if obfs_decode[1]:
+                        if not self._protocol.obfs.server_info.recv_iv:
+                            iv_len = len(self._protocol.obfs.server_info.iv)
+                            self._protocol.obfs.server_info.recv_iv = obfs_decode[0][:iv_len]
                         data = self._encryptor.decrypt(obfs_decode[0])
                     else:
                         data = obfs_decode[0]
@@ -673,6 +669,9 @@ class TCPRelayHandler(object):
                 if obfs_decode[1]:
                     send_back = self._obfs.client_encode(b'')
                     self._write_to_sock(send_back, self._remote_sock)
+                if not self._protocol.obfs.server_info.recv_iv:
+                    iv_len = len(self._protocol.obfs.server_info.iv)
+                    self._protocol.obfs.server_info.recv_iv = obfs_decode[0][:iv_len]
                 data = self._encryptor.decrypt(obfs_decode[0])
                 data = self._protocol.client_post_decrypt(data)
             else: