packet lib: fix udp header length

Fix the f5d2157 commit.

Signed-off-by: HIYAMA Manabu <hiyama.manabu@po.ntts.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
This commit is contained in:
HIYAMA Manabu 2012-10-11 17:19:57 +09:00 committed by FUJITA Tomonori
parent c42673def1
commit c92d8be079

View File

@ -24,31 +24,33 @@ class udp(packet_base.PacketBase):
_PACK_STR = '!HHHH'
_MIN_LEN = struct.calcsize(_PACK_STR)
def __init__(self, src_port, dst_port, length, csum=0):
def __init__(self, src_port, dst_port, total_length=0, csum=0):
super(udp, self).__init__()
self.src_port = src_port
self.dst_port = dst_port
self.length = length
self.total_length = total_length
self.csum = csum
self.length = udp._MIN_LEN
@classmethod
def parser(cls, buf):
(src_port, dst_port, length, csum) = struct.unpack_from(cls._PACK_STR,
buf)
msg = cls(src_port, dst_port, length, csum)
(src_port, dst_port, total_length, csum) = struct.unpack_from(
cls._PACK_STR, buf)
msg = cls(src_port, dst_port, total_length, csum)
return msg, None
def serialize(self, payload, prev):
if self.length == 0:
self.length = udp._MIN_LEN + len(payload)
if self.total_length == 0:
self.total_length = udp._MIN_LEN + len(payload)
h = struct.pack(udp._PACK_STR, self.src_port, self.dst_port,
self.length, self.csum)
self.total_length, self.csum)
if self.csum == 0:
ph = struct.pack('!IIBBH', prev.src, prev.dst, 0, 17, self.length)
ph = struct.pack('!IIBBH', prev.src, prev.dst, 0, 17,
self.total_length)
f = ph + h + payload
if len(f) % 2:
f += '\x00'
self.csum = socket.htons(packet_utils.checksum(f))
h = struct.pack(udp._PACK_STR, self.src_port, self.dst_port,
self.length, self.csum)
self.total_length, self.csum)
return h