update ns
This commit is contained in:
clowwindy
parent
795e0f4b8e
commit
7a77205530
1 changed files with 156 additions and 19 deletions
|
|
@ -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__':
|
||||
|
|
|
|||
Loading…
Reference in a new issue