From 7a772055301f0c5cebf5bbd5724411881b9b73a9 Mon Sep 17 00:00:00 2001 From: clowwindy Date: Sat, 7 Jun 2014 11:50:30 +0800 Subject: [PATCH] update ns --- shadowsocks/asyncdns.py | 175 +++++++++++++++++++++++++++++++++++----- 1 file changed, 156 insertions(+), 19 deletions(-) diff --git a/shadowsocks/asyncdns.py b/shadowsocks/asyncdns.py index 6a3f80a..b80c5dd 100644 --- a/shadowsocks/asyncdns.py +++ b/shadowsocks/asyncdns.py @@ -29,6 +29,20 @@ import common _request_count = 1 # rfc1035 +# format +# +---------------------+ +# | Header | +# +---------------------+ +# | Question | the question for the name server +# +---------------------+ +# | Answer | RRs answering the question +# +---------------------+ +# | Authority | RRs pointing toward an authority +# +---------------------+ +# | Additional | RRs holding additional information +# +---------------------+ +# +# header # 1 1 1 1 1 1 # 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 # +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ @@ -48,10 +62,22 @@ _request_count = 1 QTYPE_ANY = 255 QTYPE_A = 1 QTYPE_AAAA = 28 +QTYPE_CNAME = 5 QCLASS_IN = 1 -def convert_address(address): +def parse_ip(addrtype, data, length, offset): + if addrtype == QTYPE_A: + return socket.inet_ntop(socket.AF_INET, data[offset:offset + length]) + 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] + else: + return data + + +def pack_address(address): address = address.strip('.') labels = address.split('.') results = [] @@ -68,32 +94,137 @@ def convert_address(address): def pack_request(address): global _request_count header = struct.pack('!HBBHHHH', _request_count, 1, 0, 1, 0, 0, 0) - addr = convert_address(address) - qtype_qclass = struct.pack('!HH', QTYPE_A, QCLASS_IN) + addr = pack_address(address) + qtype_qclass = struct.pack('!HH', QTYPE_ANY, QCLASS_IN) _request_count += 1 + if _request_count > 65535: + _request_count = 1 return header + addr + qtype_qclass +def parse_name(data, offset, length=512): + 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)) + else: + labels = [] + l = ord(data[p]) + while l > 0 and p < offset + length: + if (l & (128 + 64)) == (128 + 64): + # pointer + pointer = struct.unpack('!H', data[p:p + 2])[0] + pointer = 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)) + else: + labels.append(data[p + 1:p + 1 + l]) + p += 1 + l + l = ord(data[p]) + return (p - offset + 1, '.'.join(labels)) + + +# rfc1035 +# record +# 1 1 1 1 1 1 +# 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ +# | | +# / / +# / NAME / +# | | +# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ +# | TYPE | +# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ +# | CLASS | +# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ +# | TTL | +# | | +# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ +# | RDLENGTH | +# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--| +# / RDATA / +# / / +# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ +def parse_record(data, offset, question=False): + len, 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] + ) + ip = parse_ip(record_type, data, record_rdlength, offset + len + 10) + return len + 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] + ) + return len + 4, (name, None, record_type, record_class, None, None) + + def unpack_response(data): - if len(data) > 12: - header = struct.unpack('!HBBHHHH', data[:12]) - res_id = header[0] - res_qr = header[1] & 128 - res_tc = header[1] & 2 - res_ra = header[2] & 128 - res_rcode = header[2] & 15 - res_qdcount = header[3] - res_ancount = header[4] - res_nscount = header[5] - res_arcount = header[6] - print header - # TODO detect address type - print data - print data.encode('hex') - return data + try: + if len(data) >= 12: + header = struct.unpack('!HBBHHHH', data[:12]) + res_id = header[0] + res_qr = header[1] & 128 + res_tc = header[1] & 2 + 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] + res_ancount = header[4] + res_nscount = header[5] + res_arcount = header[6] + qds = [] + ans = [] + nss = [] + ars = [] + offset = 12 + for i in xrange(0, res_qdcount): + l, r = parse_record(data, offset, True) + offset += l + if r: + qds.append(r) + for i in xrange(0, res_ancount): + l, r = parse_record(data, offset) + offset += l + if r: + ans.append(r) + 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) + + return ans + + except Exception as e: + import traceback + traceback.print_exc() + return None def resolve(address, callback): + # TODO async sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.SOL_UDP) req = pack_request(address) if req is None: @@ -109,7 +240,13 @@ def test(): def _callback(address): print address + resolve('www.twitter.com', _callback) resolve('www.google.com', _callback) + resolve('ipv6.google.com', _callback) + resolve('ipv6.l.google.com', _callback) + resolve('www.baidu.com', _callback) + resolve('www.a.shifen.com', _callback) + resolve('m.baidu.jp', _callback) if __name__ == '__main__':