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# $Id: sctp.py 23 2006-11-08 15:45:33Z dugsong $
"""Stream Control Transmission Protocol."""
import dpkt, crc32c
# Stream Control Transmission Protocol
# http://tools.ietf.org/html/rfc2960
# Chunk Types
DATA = 0
INIT = 1
INIT_ACK = 2
SACK = 3
HEARTBEAT = 4
HEARTBEAT_ACK = 5
ABORT = 6
SHUTDOWN = 7
SHUTDOWN_ACK = 8
ERROR = 9
COOKIE_ECHO = 10
COOKIE_ACK = 11
ECNE = 12
CWR = 13
SHUTDOWN_COMPLETE = 14
class SCTP(dpkt.Packet):
__hdr__ = (
('sport', 'H', 0),
('dport', 'H', 0),
('vtag', 'I', 0),
('sum', 'I', 0)
)
def unpack(self, buf):
dpkt.Packet.unpack(self, buf)
l = []
while self.data:
chunk = Chunk(self.data)
l.append(chunk)
self.data = self.data[len(chunk):]
self.data = self.chunks = l
def __len__(self):
return self.__hdr_len__ + \
sum(map(len, self.data))
def __str__(self):
l = [ str(x) for x in self.data ]
if self.sum == 0:
s = crc32c.add(0xffffffffL, self.pack_hdr())
for x in l:
s = crc32c.add(s, x)
self.sum = crc32c.done(s)
return self.pack_hdr() + ''.join(l)
class Chunk(dpkt.Packet):
__hdr__ = (
('type', 'B', INIT),
('flags', 'B', 0),
('len', 'H', 0)
)
def unpack(self, buf):
dpkt.Packet.unpack(self, buf)
self.data = self.data[:self.len - self.__hdr_len__]
if __name__ == '__main__':
import unittest
class SCTPTestCase(unittest.TestCase):
def testPack(self):
sctp = SCTP(self.s)
self.failUnless(self.s == str(sctp))
sctp.sum = 0
self.failUnless(self.s == str(sctp))
def testUnpack(self):
sctp = SCTP(self.s)
self.failUnless(sctp.sport == 32836)
self.failUnless(sctp.dport == 80)
self.failUnless(len(sctp.chunks) == 1)
self.failUnless(len(sctp) == 72)
chunk = sctp.chunks[0]
self.failUnless(chunk.type == INIT)
self.failUnless(chunk.len == 60)
s = '\x80\x44\x00\x50\x00\x00\x00\x00\x30\xba\xef\x54\x01\x00\x00\x3c\x3b\xb9\x9c\x46\x00\x01\xa0\x00\x00\x0a\xff\xff\x2b\x2d\x7e\xb2\x00\x05\x00\x08\x9b\xe6\x18\x9b\x00\x05\x00\x08\x9b\xe6\x18\x9c\x00\x0c\x00\x06\x00\x05\x00\x00\x80\x00\x00\x04\xc0\x00\x00\x04\xc0\x06\x00\x08\x00\x00\x00\x00'
unittest.main()
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