more work

shadowsocks/asyncdns.py

@@ -28,6 +28,8 @@ import common
 import eventloop
 
 
+common.patch_socket()
+
 _request_count = 1
 
 # rfc1035
@@ -99,40 +101,30 @@ def parse_ip(addrtype, data, length, offset):
     elif addrtype == QTYPE_AAAA:
         return socket.inet_ntop(socket.AF_INET6, data[offset:offset + length])
     elif addrtype == QTYPE_CNAME:
-        return parse_name(data, offset, length)[1]
+        return parse_name(data, offset)[1]
     else:
         return data
 
 
-def parse_name(data, offset, length=512):
+def parse_name(data, offset):
     p = offset
-    if (ord(data[offset]) & (128 + 64)) == (128 + 64):
-        # pointer
-        pointer = struct.unpack('!H', data[offset:offset + 2])[0]
-        pointer = pointer & 0x3FFF
-        if pointer == offset:
-            return (0, None)
-        return (2, parse_name(data, pointer)[1])
-    else:
     labels = []
     l = ord(data[p])
-        while l > 0 and p < offset + length:
+    while l > 0:
         if (l & (128 + 64)) == (128 + 64):
             # pointer
             pointer = struct.unpack('!H', data[p:p + 2])[0]
-                pointer = pointer & 0x3FFF
+            pointer &= 0x3FFF
-                # if pointer == offset:
-                #     return (0, None)
             r = parse_name(data, pointer)
             labels.append(r[1])
             p += 2
             # pointer is the end
-                return (p - offset + 1, '.'.join(labels))
+            return p - offset, '.'.join(labels)
         else:
             labels.append(data[p + 1:p + 1 + l])
             p += 1 + l
         l = ord(data[p])
-        return (p - offset + 1, '.'.join(labels))
+    return p - offset + 1, '.'.join(labels)
 
 
 # rfc1035
@@ -158,33 +150,30 @@ def parse_name(data, offset, length=512):
 #    /                                               /
 #    +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
 def parse_record(data, offset, question=False):
-    len, name = parse_name(data, offset)
+    nlen, name = parse_name(data, offset)
-    # TODO
-    assert len
     if not question:
         record_type, record_class, record_ttl, record_rdlength = struct.unpack(
-            '!HHiH', data[offset + len:offset + len + 10]
+            '!HHiH', data[offset + nlen:offset + nlen + 10]
         )
-        ip = parse_ip(record_type, data, record_rdlength, offset + len + 10)
+        ip = parse_ip(record_type, data, record_rdlength, offset + nlen + 10)
-        return len + 10 + record_rdlength, \
+        return nlen + 10 + record_rdlength, \
             (name, ip, record_type, record_class, record_ttl)
     else:
         record_type, record_class = struct.unpack(
-            '!HH', data[offset + len:offset + len + 4]
+            '!HH', data[offset + nlen:offset + nlen + 4]
         )
-        return len + 4, (name, None, record_type, record_class, None, None)
+        return nlen + 4, (name, None, record_type, record_class, None, None)
 
 
 def parse_response(data):
     try:
         if len(data) >= 12:
             header = struct.unpack('!HBBHHHH', data[:12])
-            res_id = header[0]
+            # res_id = header[0]
-            res_qr = header[1] & 128
+            # res_qr = header[1] & 128
             res_tc = header[1] & 2
-            res_ra = header[2] & 128
+            # res_ra = header[2] & 128
             res_rcode = header[2] & 15
-            # TODO check tc and rcode
             assert res_tc == 0
             assert res_rcode == 0
             res_qdcount = header[3]
@@ -193,8 +182,6 @@ def parse_response(data):
             res_arcount = header[6]
             qds = []
             ans = []
-            nss = []
-            ars = []
             offset = 12
             for i in xrange(0, res_qdcount):
                 l, r = parse_record(data, offset, True)
@@ -209,13 +196,9 @@ def parse_response(data):
             for i in xrange(0, res_nscount):
                 l, r = parse_record(data, offset)
                 offset += l
-                if r:
-                    nss.append(r)
             for i in xrange(0, res_arcount):
                 l, r = parse_record(data, offset)
                 offset += l
-                if r:
-                    ars.append(r)
             response = DNSResponse()
             if qds:
                 response.hostname = qds[0][0]
@@ -225,6 +208,7 @@ def parse_response(data):
     except Exception as e:
         import traceback
         traceback.print_exc()
+        logging.error(e)
         return None
 
 
@@ -380,9 +364,9 @@ def test():
     resolver = DNSResolver()
     resolver.add_to_loop(loop)
 
+    resolver.resolve('www.google.com', _callback)
     resolver.resolve('8.8.8.8', _callback)
     resolver.resolve('www.twitter.com', _callback)
-    resolver.resolve('www.google.com', _callback)
     resolver.resolve('ipv6.google.com', _callback)
     resolver.resolve('ipv6.l.google.com', _callback)
     resolver.resolve('www.gmail.com', _callback)

shadowsocks/common.py

@@ -63,6 +63,7 @@ def inet_pton(family, addr):
         raise RuntimeError("What family?")
 
 
+def patch_socket():
     if not hasattr(socket, 'inet_pton'):
         socket.inet_pton = inet_pton
 
@@ -70,6 +71,9 @@ if not hasattr(socket, 'inet_ntop'):
         socket.inet_ntop = inet_ntop
 
 
+patch_socket()
+
+
 ADDRTYPE_IPV4 = 1
 ADDRTYPE_IPV6 = 4
 ADDRTYPE_HOST = 3