def unpack(cls, msg):
"""
Factory function.
Return a NOTIFICATION object corresponding to the given packed msg.
"""
length, type = Message.header_unpack(msg[:19])
error_code, error_subcode = struct.unpack('!BB', msg[19:21])
if length > 21:
data = struct.unpack('!%ds' % (length - 21), msg[21:length])
return cls(error_code, error_subcode, data)
def unpack(cls, msg):
"""
Factory function.
Return a OPEN object corresponding to the given packed msg.
"""
length, type = Message.header_unpack(msg)
if type != Type.OPEN:
raise Exception
version, asn, hold_time, router_id = struct.unpack('!BHHI', msg[19:28])
length_capabilities = struct.unpack('!B', msg[28:29])
if length_capabilities:
pass
return cls(asn, hold_time, router_id)
def unpack(cls, msg):
"""
Factory function. Return a UPDATE object corresponding
to the msg unpacked.
"""
length, type = Message.header_unpack(msg)
msg = msg[19:]
# Unpack Withdrawn routes
wd_routes_length, = struct.unpack('!H', msg[:2])
wd_routes = []
wr_packed = msg[2:2+wd_routes_length]
while(wr_packed):
ipfield = IPField.unpack(wr_packed)
wd_routes.append(ipfield)
wr_packed = wr_packed[len(ipfield):]
msg = msg[2+wd_routes_length:]
# Unpack Path Attributes
path_attrs_length, = struct.unpack('!H', msg[:2])
path_attrs = []
pa_packed = msg[2:2+path_attrs_length]
while(pa_packed):
path_attr = PathAttribute.create(pa_packed)
path_attrs.append(path_attr)
pa_packed = pa_packed[len(path_attr):]
msg = msg[2+path_attrs_length:]
# Unpack NLRI
nlris = []
nlris_packed = msg[:length]
while(nlris_packed):
ipfield = IPField.unpack(nlris_packed)
nlris.append(ipfield)
nlris_packed = nlris_packed[len(ipfield):]
return cls(wd_routes, path_attrs, nlris)
