def _ota_chunk_data(self, data, data_cb):
# spec https://shadowsocks.org/en/spec/one-time-auth.html
unchunk_data = b''
while len(data) > 0:
if self._ota_len == 0:
# get DATA.LEN + HMAC-SHA1
length = ONETIMEAUTH_CHUNK_BYTES - len(self._ota_buff_head)
self._ota_buff_head += data[:length]
data = data[length:]
if len(self._ota_buff_head) < ONETIMEAUTH_CHUNK_BYTES:
# wait more data
return
data_len = self._ota_buff_head[:ONETIMEAUTH_CHUNK_DATA_LEN]
self._ota_len = struct.unpack('>H', data_len)[0]
length = min(self._ota_len - len(self._ota_buff_data), len(data))
self._ota_buff_data += data[:length]
data = data[length:]
if len(self._ota_buff_data) == self._ota_len:
# get a chunk data
_hash = self._ota_buff_head[ONETIMEAUTH_CHUNK_DATA_LEN:]
_data = self._ota_buff_data
index = struct.pack('>I', self._ota_chunk_idx)
key = self._cryptor.decipher_iv + index
if onetimeauth_verify(_hash, _data, key) is False:
logging.warn('one time auth fail, drop chunk !')
else:
unchunk_data += _data
self._ota_chunk_idx += 1
self._ota_buff_head = b''
self._ota_buff_data = b''
self._ota_len = 0
data_cb(unchunk_data)
return
def _ota_chunk_data(self, data, data_cb):
# spec https://shadowsocks.org/en/spec/one-time-auth.html
# 前面数据是 len + hac-sha1，这里就是处理粘包情况，每个数据头
# 都有一个len字段表示这段数据的长度，每个数据包都有一个hmac-sha1
# hmac-sha1是iv+包序列号计算得到
# +----------+-----------+----------+----
# | DATA.LEN | HMAC - SHA1 | DATA | ...
# +----------+-----------+----------+----
# | 2 | 10 | Variable | ...
# +----------+-----------+----------+----
while len(data) > 0:
if self._ota_len == 0:
# get DATA.LEN + HMAC-SHA1
# 总共12字节，2字节长度，10字节hmac-sha1，这里是取得
# len和hmac-sha1，赋值给ota_len
length = ONETIMEAUTH_CHUNK_BYTES - len(self._ota_buff_head)
# 去后面的数据，length字段超过len(data)也没关系，python列表的data[:len]超过len(data)
# 只会得到len(data)大小的数据
self._ota_buff_head += data[:length]
data = data[length:]
# 还没完整取得整个包头
if len(self._ota_buff_head) < ONETIMEAUTH_CHUNK_BYTES:
# wait more data
return
# 得到data.len
data_len = self._ota_buff_head[:ONETIMEAUTH_CHUNK_DATA_LEN]
self._ota_len = struct.unpack('>H', data_len)[0]
# 开始取数据
length = min(self._ota_len, len(data))
self._ota_buff_data += data[:length]
data = data[length:]
# 得到一个完整数据包，开始校验 hmac-ha1
if len(self._ota_buff_data) == self._ota_len:
# get a chunk data
# 跨过2字节len
_hash = self._ota_buff_head[ONETIMEAUTH_CHUNK_DATA_LEN:]
_data = self._ota_buff_data
# 计数器 iv+counter作为key
index = struct.pack('>I', self._ota_chunk_idx)
key = self._encryptor.decipher_iv + index
if onetimeauth_verify(_hash, _data, key) is False:
logging.warn('one time auth fail, drop chunk !')
else:
data_cb(self._ota_buff_data)
self._ota_chunk_idx += 1
self._ota_buff_head = b''
self._ota_buff_data = b''
self._ota_len = 0
return
def _handle_stage_addr(self, data):
try:
if self._is_local:
cmd = common.ord(data[1])
if cmd == CMD_UDP_ASSOCIATE:
logging.debug('UDP associate')
if self._local_sock.family == socket.AF_INET6:
# 0x4 ipv6
header = b'\x05\x00\x00\x04'
else:
# 0x1 ipv4
header = b'\x05\x00\x00\x01'
addr, port = self._local_sock.getsockname()[:2]
addr_to_send = socket.inet_pton(self._local_sock.family,
addr)
port_to_send = struct.pack('>H', port)
# 响应 CMD_UDP_ASSOCIATE 命令，告诉客户端udp地址
self._write_to_sock(header + addr_to_send + port_to_send,
self._local_sock)
self._stage = STAGE_UDP_ASSOC
# just wait for the client to disconnect
# 这里已经返回
return
elif cmd == CMD_CONNECT:
# just trim VER CMD RSV
# 跨过socks5前面3字节，后面字节与socks5兼容，不过在addrtype字段加入了ota验证
data = data[3:]
else:
# bing命令？
logging.error('unknown command %d', cmd)
self.destroy()
return
# 服务器端初始时候解析包头，下面也是socks5请求时从第三个字节开始的地址数据
# 这里ssserver刚好兼容剩下的socks5的请求头
header_result = parse_header(data)
if header_result is None:
raise Exception('can not parse header')
addrtype, remote_addr, remote_port, header_length = header_result
# 经常看到的服务器接收到请求时候打印的日志
logging.info('connecting %s:%d from %s:%d' %
(common.to_str(remote_addr), remote_port,
self._client_address[0], self._client_address[1]))
if self._is_local is False:
# spec https://shadowsocks.org/en/spec/one-time-auth.html
# 验证ota正确性
if self._ota_enable or addrtype & ADDRTYPE_AUTH:
self._ota_enable = True
if len(data) < header_length + ONETIMEAUTH_BYTES:
logging.warn('one time auth header is too short')
return None
offset = header_length + ONETIMEAUTH_BYTES
# header后的一段hash值, 10字节one-time-auth
_hash = data[header_length:offset]
_data = data[:header_length]
# iv+key
key = self._encryptor.decipher_iv + self._encryptor.key
# 验证是否允许
if onetimeauth_verify(_hash, _data, key) is False:
logging.warn('one time auth fail')
self.destroy()
return
header_length += ONETIMEAUTH_BYTES
self._remote_address = (common.to_str(remote_addr), remote_port)
# pause reading 上送数据
self._update_stream(STREAM_UP, WAIT_STATUS_WRITING)
self._stage = STAGE_DNS
if self._is_local:
# 客户端
# forward address to remote
# 告诉浏览器，socks5验证成功
self._write_to_sock((b'\x05\x00\x00\x01'
b'\x00\x00\x00\x00\x10\x10'),
self._local_sock)
# spec https://shadowsocks.org/en/spec/one-time-auth.html
# ATYP & 0x10 == 1, then OTA is enabled.
if self._ota_enable:
# 自己实现的ota，在浏览器之类发来的socks5请求头部的addrtype中加入ADDRTYPE_AUTH
# 然后发往ssserver，修改第一字节，实际是socks5头部的第3字节
data = common.chr(addrtype | ADDRTYPE_AUTH) + data[1:]
key = self._encryptor.cipher_iv + self._encryptor.key
# 附在数据尾部? 这里的data是socks5请求报文第三字节之后的数据
data += onetimeauth_gen(data, key)
# 加密
data_to_send = self._encryptor.encrypt(data)
self._data_to_write_to_remote.append(data_to_send)
# notice here may go into _handle_dns_resolved directly
# 选择一个ssserver发送数据
self._dns_resolver.resolve(self._chosen_server[0],
self._handle_dns_resolved)
else:
# 服务端
if self._ota_enable:
# 过滤前面的远程地址和ota hmac-sha1头
data = data[header_length:]
self._ota_chunk_data(data,
self._data_to_write_to_remote.append)
elif len(data) > header_length:
# 过滤掉头部还有数据要发送
self._data_to_write_to_remote.append(data[header_length:])
# notice here may go into _handle_dns_resolved directly
# 解析dns之后remote_sock连接远端web站点
self._dns_resolver.resolve(remote_addr,
self._handle_dns_resolved)
except Exception as e:
self._log_error(e)
if self._config['verbose']:
traceback.print_exc()
self.destroy()
def _handle_server(self):
server = self._server_socket
data, r_addr = server.recvfrom(BUF_SIZE)
key = None
iv = None
if not data:
logging.debug('UDP handle_server: data is empty')
if self._stat_callback:
self._stat_callback(self._listen_port, len(data))
if self._is_local:
frag = common.ord(data[2])
if frag != 0:
logging.warn('UDP drop a message since frag is not 0')
return
else:
# RSV and FRAG are dropped
data = data[3:]
else:
# 服务器解密
data, key, iv = encrypt.dencrypt_all(self._password, self._method,
data)
# decrypt data
if not data:
logging.debug('UDP handle_server: data is empty after decrypt')
return
# +------+---------------------+------------------+----------+-----------+
# | ATYP | Destination Address | Destination Port | DATA | HMAC - SHA1 |
# +------+---------------------+------------------+----------+-----------+
# | 1 | Variable | 2 | Variable | 10 |
# +------+---------------------+------------------+----------+-----------+
header_result = parse_header(data)
if header_result is None:
return
addrtype, dest_addr, dest_port, header_length = header_result
if self._is_local:
server_addr, server_port = self._get_a_server()
else:
# 服务端拆包，ota验证
server_addr, server_port = dest_addr, dest_port
# spec https://shadowsocks.org/en/spec/one-time-auth.html
if self._one_time_auth_enable or addrtype & ADDRTYPE_AUTH:
self._one_time_auth_enable = True
if len(data) < header_length + ONETIMEAUTH_BYTES:
logging.warn('UDP one time auth header is too short')
return
# 尾巴的hmac-sha1
_hash = data[-ONETIMEAUTH_BYTES:]
data = data[:-ONETIMEAUTH_BYTES]
_key = iv + key
if onetimeauth_verify(_hash, data, _key) is False:
logging.warn('UDP one time auth fail')
return
addrs = self._dns_cache.get(server_addr, None)
if addrs is None:
# 同步查询DNS
addrs = socket.getaddrinfo(server_addr, server_port, 0,
socket.SOCK_DGRAM, socket.SOL_UDP)
if not addrs:
# drop
return
else:
self._dns_cache[server_addr] = addrs
af, socktype, proto, canonname, sa = addrs[0]
key = client_key(r_addr, af)
client = self._cache.get(key, None)
if not client:
# 创建client socket
# TODO async getaddrinfo
if self._forbidden_iplist:
if common.to_str(sa[0]) in self._forbidden_iplist:
logging.debug('IP %s is in forbidden list, drop' %
common.to_str(sa[0]))
# drop
return
client = socket.socket(af, socktype, proto)
client.setblocking(False)
self._cache[key] = client
# 记录数据要返回给谁
self._client_fd_to_server_addr[client.fileno()] = r_addr
self._sockets.add(client.fileno())
self._eventloop.add(client, eventloop.POLL_IN, self)
if self._is_local:
# 客户端 ota数据生成，然后加密
key, iv, m = encrypt.gen_key_iv(self._password, self._method)
# spec https://shadowsocks.org/en/spec/one-time-auth.html
if self._one_time_auth_enable:
data = self._ota_chunk_data_gen(key, iv, data)
data = encrypt.encrypt_all_m(key, iv, m, self._method, data)
if not data:
return
else:
# 服务器忽略前面的地址与端口头
data = data[header_length:]
if not data:
return
try:
# 数据上行upstream
client.sendto(data, (server_addr, server_port))
except IOError as e:
err = eventloop.errno_from_exception(e)
if err in (errno.EINPROGRESS, errno.EAGAIN):
pass
else:
shell.print_exception(e)
def _handle_stage_addr(self, data):
if self._is_local:
if self._is_tunnel:
# add ss header to data
tunnel_remote = self.tunnel_remote
tunnel_remote_port = self.tunnel_remote_port
data = common.add_header(tunnel_remote, tunnel_remote_port,
data)
else:
cmd = common.ord(data[1])
if cmd == CMD_UDP_ASSOCIATE:
logging.debug('UDP associate')
if self._local_sock.family == socket.AF_INET6:
header = b'\x05\x00\x00\x04'
else:
header = b'\x05\x00\x00\x01'
addr, port = self._local_sock.getsockname()[:2]
addr_to_send = socket.inet_pton(self._local_sock.family,
addr)
port_to_send = struct.pack('>H', port)
self._write_to_sock(header + addr_to_send + port_to_send,
self._local_sock)
self._stage = STAGE_UDP_ASSOC
# just wait for the client to disconnect
return
elif cmd == CMD_CONNECT:
# just trim VER CMD RSV
data = data[3:]
else:
logging.error('unknown command %d', cmd)
self.destroy()
return
header_result = parse_header(data)
if header_result is None:
raise Exception('can not parse header')
addrtype, remote_addr, remote_port, header_length = header_result
logging.info('connecting %s:%d from %s:%d' %
(common.to_str(remote_addr), remote_port,
self._client_address[0], self._client_address[1]))
#logging.info('connecting %s:%d from %s:%d, %s' %
# (common.to_str(remote_addr), remote_port,
# self._client_address[0], self._client_address[1], data))
if self._is_local is False:
# spec https://shadowsocks.org/en/spec/one-time-auth.html
self._ota_enable_session = addrtype & ADDRTYPE_AUTH
if self._ota_enable and not self._ota_enable_session:
logging.warn('client one time auth is required')
return
if self._ota_enable_session:
if len(data) < header_length + ONETIMEAUTH_BYTES:
logging.warn('one time auth header is too short')
return None
offset = header_length + ONETIMEAUTH_BYTES
_hash = data[header_length:offset]
_data = data[:header_length]
key = self._cryptor.decipher_iv + self._cryptor.key
if onetimeauth_verify(_hash, _data, key) is False:
logging.warn('one time auth fail')
self.destroy()
return
header_length += ONETIMEAUTH_BYTES
self._remote_address = (common.to_str(remote_addr), remote_port)
# pause reading
self._update_stream(STREAM_UP, WAIT_STATUS_WRITING)
self._stage = STAGE_DNS
if self._is_local:
# jump over socks5 response
if not self._is_tunnel:
# forward address to remote
self._write_to_sock((b'\x05\x00\x00\x01'
b'\x00\x00\x00\x00\x10\x10'),
self._local_sock)
# spec https://shadowsocks.org/en/spec/one-time-auth.html
# ATYP & 0x10 == 0x10, then OTA is enabled.
if self._ota_enable_session:
data = common.chr(addrtype | ADDRTYPE_AUTH) + data[1:]
key = self._cryptor.cipher_iv + self._cryptor.key
_header = data[:header_length]
sha110 = onetimeauth_gen(data, key)
data = _header + sha110 + data[header_length:]
data_to_send = self._cryptor.encrypt(data)
self._data_to_write_to_remote.append(data_to_send)
# notice here may go into _handle_dns_resolved directly
self._dns_resolver.resolve(self._chosen_server[0],
self._handle_dns_resolved)
else:
if self._ota_enable_session:
data = data[header_length:]
self._ota_chunk_data(data,
self._data_to_write_to_remote.append)
elif len(data) > header_length:
self._data_to_write_to_remote.append(data[header_length:])
# notice here may go into _handle_dns_resolved directly
self._dns_resolver.resolve(remote_addr, self._handle_dns_resolved)
def _handle_server(self):
server = self._server_socket
data, r_addr = server.recvfrom(BUF_SIZE)
key = None
iv = None
if not data:
logging.debug('UDP handle_server: data is empty')
if self._stat_callback:
self._stat_callback(self._listen_port, len(data))
if self._is_local:
if self._is_tunnel:
# add ss header to data
tunnel_remote = self.tunnel_remote
tunnel_remote_port = self.tunnel_remote_port
data = common.add_header(tunnel_remote, tunnel_remote_port,
data)
else:
frag = common.ord(data[2])
if frag != 0:
logging.warn('UDP drop a message since frag is not 0')
return
else:
data = data[3:]
else:
# decrypt data
try:
data, key, iv = cryptor.decrypt_all(self._password,
self._method, data,
self._crypto_path)
except Exception:
logging.debug('UDP handle_server: decrypt data failed')
return
if not data:
logging.debug('UDP handle_server: data is empty after decrypt')
return
header_result = parse_header(data)
if header_result is None:
return
addrtype, dest_addr, dest_port, header_length = header_result
logging.info("udp data to %s:%d from %s:%d" %
(dest_addr, dest_port, r_addr[0], r_addr[1]))
if self._is_local:
server_addr, server_port = self._get_a_server()
else:
server_addr, server_port = dest_addr, dest_port
# spec https://shadowsocks.org/en/spec/one-time-auth.html
self._ota_enable_session = addrtype & ADDRTYPE_AUTH
if self._ota_enable and not self._ota_enable_session:
logging.warn('client one time auth is required')
return
if self._ota_enable_session:
if len(data) < header_length + ONETIMEAUTH_BYTES:
logging.warn('UDP one time auth header is too short')
return
_hash = data[-ONETIMEAUTH_BYTES:]
data = data[:-ONETIMEAUTH_BYTES]
_key = iv + key
if onetimeauth_verify(_hash, data, _key) is False:
logging.warn('UDP one time auth fail')
return
addrs = self._dns_cache.get(server_addr, None)
if addrs is None:
addrs = socket.getaddrinfo(server_addr, server_port, 0,
socket.SOCK_DGRAM, socket.SOL_UDP)
if not addrs:
# drop
return
else:
self._dns_cache[server_addr] = addrs
af, socktype, proto, canonname, sa = addrs[0]
key = client_key(r_addr, af)
client = self._cache.get(key, None)
if not client:
# TODO async getaddrinfo
if self._forbidden_iplist:
if common.to_str(sa[0]) in self._forbidden_iplist:
logging.debug('IP %s is in forbidden list, drop' %
common.to_str(sa[0]))
# drop
return
client = socket.socket(af, socktype, proto)
client.setblocking(False)
self._cache[key] = client
self._client_fd_to_server_addr[client.fileno()] = r_addr
self._sockets.add(client.fileno())
self._eventloop.add(client, eventloop.POLL_IN, self)
if self._is_local:
key, iv, m = cryptor.gen_key_iv(self._password, self._method)
# spec https://shadowsocks.org/en/spec/one-time-auth.html
if self._ota_enable_session:
data = self._ota_chunk_data_gen(key, iv, data)
try:
data = cryptor.encrypt_all_m(key, iv, m, self._method, data,
self._crypto_path)
except Exception:
logging.debug("UDP handle_server: encrypt data failed")
return
if not data:
return
else:
data = data[header_length:]
if not data:
return
try:
client.sendto(data, (server_addr, server_port))
except IOError as e:
err = eventloop.errno_from_exception(e)
if err in (errno.EINPROGRESS, errno.EAGAIN):
pass
else:
shell.print_exception(e)