add SMART DIRECT feature

README.md

@@ -104,6 +104,10 @@ Please notice that some encryption methods are not available on some environment
 Performance
 ------------
 
+You may use -d option to enable SMART DRIRECT feature. If SMART DIRECT is enabled, connection will be established directly to destination IPs in China.
+
+    python local.py -d
+
 You may want to install gevent for better performance.
 
     $ sudo apt-get install python-gevent

shadowsocks/isdirect.py

@@ -0,0 +1,75 @@
+#!/usr/bin/env python
+
+import sys
+import socket
+import bisect
+
+def ip2int(ip):
+    return reduce(lambda x,y: x*256+y, [int(x) for x in ip.split('.')])
+
+def init_geolite():
+    import urllib2
+    import zipfile
+    import StringIO
+    buf = StringIO.StringIO(urllib2.urlopen("http://geolite.maxmind.com/download/geoip/database/GeoIPCountryCSV.zip").read())
+    geolite_begin = []
+    geolite_end = []
+    for line in zipfile.ZipFile(buf).open('GeoIPCountryWhois.csv').readlines():
+        ip_begin, ip_end, int_begin, int_end, code = line.strip().split(',')[0:5] 
+        if code == '"CN"':
+            geolite_begin.append(int(int_begin[1:-1]))
+            geolite_end.append(int(int_end[1:-1]))
+    for ip_begin, ip_end in internal_ip:
+        ipb = ip2int(ip_begin)
+        ipe = ip2int(ip_end)
+        i = bisect.bisect(geolite_begin, ipb)
+        geolite_begin.insert(i, ipb)
+        geolite_end.insert(i, ipe)
+    return (geolite_begin, geolite_end)
+
+def ischina(ip_int):
+    if geolite:
+        i = bisect.bisect_right(geolite[0], ip_int) -1
+        if i == 0 or ip_int > geolite[1][i]:
+            return False
+        else:
+            return True
+    else:
+        return False
+
+def isdirect(hostname):
+    hostname = hostname.strip()
+    try:
+        ip = socket.gethostbyname(hostname)
+    except Exception, e:
+        ip = "0.0.0.0"
+    ip_int = ip2int(ip)
+    try:
+        is_china = ischina(ip_int)
+    except Exception, e:
+        is_china = False
+
+    return  is_china and \
+            (ip_int not in blacklist_ip) and \
+            (not any([hostname.endswith(i) for i in blacklist_domain])) \
+            or \
+            (any([hostname.endswith(i) for i in whitelist_domain]))
+
+#bad IPs returned by domestic DNS servers
+blacklist_ip =[ip2int(ip) for ip in ['60.191.124.236', '180.168.41.175', '93.46.8.89', '203.98.7.65', '8.7.198.45', '78.16.49.15', '46.82.174.68', '243.185.187.39', '243.185.187.30', '159.106.121.75', '37.61.54.158', '159.24.3.173', '0.0.0.0']]
+#domains hijacked
+blacklist_domain = ['skype.com', 'youtube.com']
+#private IP ranges
+internal_ip = [("127.0.0.0", "127.255.255.255"), ("192.168.0.0", "192.168.255.255"), ("172.16.0.0", "172.31.255.255"), ("10.0.0.0", "10.255.255.255")]
+#private domain names
+whitelist_domain = ['local', 'localhost' ]
+
+geolite = init_geolite()
+
+if __name__ == "__main__":
+    while 1:
+        line=sys.stdin.readline()
+        if line == "":
+            break
+        print("OK" if isdirect(line) else "ERR")
+        sys.stdout.flush()

shadowsocks/local.py

@@ -35,6 +35,12 @@ except ImportError:
     gevent = None
     print >>sys.stderr, 'warning: gevent not found, using threading instead'
 
+try:
+    import isdirect
+except ImportError:
+    isdirect = None
+    print >>sys.stderr, 'error importing isdirect, SMART_DIRECT feature disabled'
+
 import socket
 import select
 import SocketServer
@@ -62,13 +68,16 @@ class ThreadingTCPServer(SocketServer.ThreadingMixIn, SocketServer.TCPServer):
 
 
 class Socks5Server(SocketServer.StreamRequestHandler):
-    def handle_tcp(self, sock, remote):
+    def handle_tcp(self, sock, remote, direct):
         try:
             fdset = [sock, remote]
             while True:
                 r, w, e = select.select(fdset, [], [])
                 if sock in r:
-                    data = self.encrypt(sock.recv(4096))
+                    if direct:
+                        data = sock.recv(4096)
+                    else:
+                        data = self.encrypt(sock.recv(4096))
                     if len(data) <= 0:
                         break
                     result = send_all(remote, data)
@@ -76,7 +85,10 @@ class Socks5Server(SocketServer.StreamRequestHandler):
                         raise Exception('failed to send all data')
 
                 if remote in r:
-                    data = self.decrypt(remote.recv(4096))
+                    if direct:
+                        data = remote.recv(4096)
+                    else:
+                        data = self.decrypt(remote.recv(4096))
                     if len(data) <= 0:
                         break
                     result = send_all(sock, data)
@@ -127,24 +139,29 @@ class Socks5Server(SocketServer.StreamRequestHandler):
             addr_port = self.rfile.read(2)
             addr_to_send += addr_port
             port = struct.unpack('>H', addr_port)
+            direct = SMART_DIRECT and isdirect.isdirect(addr)
             try:
                 reply = "\x05\x00\x00\x01"
                 reply += socket.inet_aton('0.0.0.0') + struct.pack(">H", 2222)
                 self.wfile.write(reply)
                 # reply immediately
-                remote = socket.create_connection((SERVER, REMOTE_PORT))
+                if direct:
-                self.send_encrypt(remote, addr_to_send)
+                    remote = socket.create_connection((addr, port[0]))
-                logging.info('connecting %s:%d' % (addr, port[0]))
+                    logging.info('direct connecting %s:%d' % (addr, port[0]))
+                else:
+                    remote = socket.create_connection((SERVER, REMOTE_PORT))
+                    self.send_encrypt(remote, addr_to_send)
+                    logging.info('connecting %s:%d' % (addr, port[0]))
             except socket.error, e:
                 logging.warn(e)
                 return
-            self.handle_tcp(sock, remote)
+            self.handle_tcp(sock, remote, direct)
         except socket.error, e:
             logging.warn(e)
 
 
 def main():
-    global SERVER, REMOTE_PORT, PORT, KEY, METHOD, LOCAL, IPv6
+    global SERVER, REMOTE_PORT, PORT, KEY, METHOD, LOCAL, IPv6, SMART_DIRECT
     
     logging.basicConfig(level=logging.DEBUG,
                         format='%(asctime)s %(levelname)-8s %(message)s',
@@ -167,9 +184,10 @@ def main():
     METHOD = None
     LOCAL = ''
     IPv6 = False
+    SMART_DIRECT = False
     
     config_path = utils.find_config()
-    optlist, args = getopt.getopt(sys.argv[1:], 's:b:p:k:l:m:c:6')
+    optlist, args = getopt.getopt(sys.argv[1:], 's:b:p:k:l:m:c:6d')
     for key, value in optlist:
         if key == '-c':
             config_path = value
@@ -178,8 +196,10 @@ def main():
         logging.info('loading config from %s' % config_path)
         with open(config_path, 'rb') as f:
             config = json.load(f)
-    optlist, args = getopt.getopt(sys.argv[1:], 's:b:p:k:l:m:c:6')
+    optlist, args = getopt.getopt(sys.argv[1:], 's:b:p:k:l:m:c:6d')
     for key, value in optlist:
+        if key == '-d':
+            SMART_DIRECT = (isdirect is not None)
         if key == '-p':
             config['server_port'] = int(value)
         elif key == '-k':