def __init__(self, name, **kv):
self.packet = None
self.name = name
self.len = pcs.Field("len", 16)
self.flags = pcs.Field("flags", 8)
self.hops = pcs.Field("hops", 8)
self.ifindex = pcs.Field("ifindex", 32)
self.tlvs = pcs.OptionListField("tlvs")
# XXX I actually have variable width when I am being encoded,
# OptionList deals with this.
self.width = self.len.width + self.flags.width + \
self.hops.width + self.ifindex.width + \
self.tlvs.width
# If keyword initializers are present, deal with the syntactic sugar.
# TODO: Figure out how to initialize the TLVs inside our TLV...
if kv is not None:
for kw in kv.iteritems():
if kw[0] in self.__dict__:
if kw[0] == 'tlvs':
if not isinstance(kw[1], list):
if __debug__:
print "argument is not a list"
continue
#for src in kw[1]:
# if not isinstance(src, int):
# if __debug__:
# print "source is not an IPv4 address"
# continue
# self.sources.append(pcs.Field("", 32, default=src))
else:
self.__dict__[kw[0]].value = kw[1]
def __init__(self, bytes=None, timestamp=None, **kv):
"""common header initialization"""
type = pcs.Field("type", 8, default=0)
reserved = pcs.Field("reserved", 5)
unordered = pcs.Field("unordered", 1)
beginning = pcs.Field("beginning", 1)
ending = pcs.Field("ending", 1)
length = pcs.Field("length", 16)
tsn = pcs.Field("tsn", 32)
stream_id = pcs.Field("stream_id", 16)
stream_seq = pcs.Field("stream_seq", 16)
ppi = pcs.Field("ppi", 32)
pcs.Packet.__init__(self, [
type, reserved, unordered, beginning, ending, length, tsn,
stream_im, stream_seq, ppi
],
bytes=bytes,
**kv)
self.description = "SCTP payload chunk class"
if timestamp is None:
self.timestamp = time.time()
else:
self.timestamp = timestamp
if (bytes is not None):
self.data = self.next(bytes[0:len(bytes)], timestamp=timestamp)
else:
self.data = None
def __init__(self, bytes=None, timestamp=None, **kv):
family = pcs.Field("family", 8)
prefixlen = pcs.Field("pad00", 8)
flags = pcs.Field("flags", 8)
scope = pcs.Field("scope", 8)
index = pcs.Field("index", 32)
#tlvs = pcs.OptionListField("tlvs")
pcs.Packet.__init__(self, [family, prefixlen, flags, scope, index],\
bytes = bytes, **kv)
self.description = "RFC 3549 interface address message."
if timestamp is None:
self.timestamp = time.time()
else:
self.timestamp = timestamp
if bytes is not None:
offset = self.sizeof()
remaining = len(bytes) - offset
# TODO demux TLVs.
if self.data is None:
self.data = payload.payload(bytes[offset:remaining], \
timestamp=timestamp)
else:
self.data = None
def __init__(self, bytes=None, timestamp=None, **kv):
"""initialize an IGMPv3 report header"""
reserved00 = pcs.Field("reserved00", 16)
nrecords = pcs.Field("nrecords", 16)
records = pcs.OptionListField("records")
pcs.Packet.__init__(self, [reserved00, nrecords, records], bytes, **kv)
self.description = "initialize an IGMPv3 report header"
if timestamp is None:
self.timestamp = time.time()
else:
self.timestamp = timestamp
# Decode additional bytes into group records, if provided.
# Group records are variable length structures.
# Some IGMPv3 implementations re-use the same buffers which
# may contain junk, so don't try to parse the entire packet
# as a set of group record fields.
if bytes is not None:
curr = self.sizeof()
byteBR = 8
found = 0
expected = self._fieldnames['nrecords'].value
while len(self.records) < expected and curr < len(bytes):
rec = GroupRecordField("")
oldcurr = curr
[dummy, curr, byteBR] = rec.decode(bytes, curr, byteBR)
self.records.append(rec)
#print len(self.records), "records parsed"
self.data = payload.payload(bytes[curr:len(bytes)])
else:
self.data = None
def __init__(self, bytes=None):
"""IPv6 routing extension header from RFC 2460"""
next = pcs.Field("next_header", 8)
len = pcs.Field("length", 8)
type = pcs.Field("type", 8)
segments_left = pcs.Field("segments_left", 8)
pcs.Packet.__init__(self, [next, len, type, segments_left], bytes)
def __init__(self, bytes=None, timestamp=None, **kv):
"""Followup Header """
preciseOriginTimestampSeconds = pcs.Field(
"preciseOriginTimestampSeconds", 48)
preciseOriginTimestampNanoSeconds = pcs.Field(
"preciseOriginTimestampNanoSeconds", 32)
pcs.Packet.__init__(
self,
[preciseOriginTimestampSeconds, preciseOriginTimestampNanoSeconds],
bytes=bytes,
**kv)
self.description = "Followup"
if timestamp is None:
self.timestamp = time.time()
else:
self.timestamp = timestamp
if (bytes is not None):
self.data = self.next(bytes[self.sizeof():len(bytes)],
timestamp=timestamp)
else:
self.data = None
def __init__(self, bytes=None, timestamp=None, **kv):
"""initialize a header very similar to that of IGMPv1/v2"""
reserved00 = pcs.Field("reserved00", 8)
capabilities = pcs.Field("capabilities", 8)
minor = pcs.Field("minor", 8)
major = pcs.Field("major", 8)
options = pcs.OptionListField("options")
pcs.Packet.__init__(self,
[reserved00, capabilities, minor, major, options],
bytes, **kv)
self.description = "initialize a header very similar to that of IGMPv1/v2"
if timestamp is None:
self.timestamp = time.time()
else:
self.timestamp = timestamp
# XXX optional bytes not processed yet.
if bytes is not None:
offset = self.sizeof()
self.data = payload.payload(bytes[offset:len(bytes)])
else:
self.data = None
def __init__(self, bytes = None, timestamp = None, **kv):
"""initialize the common header """
versionPTP = pcs.Field("versionPTP", 16)
versionNetwork = pcs.Field("versionNetwork", 16)
subdomain = pcs.StringField("subdomain", PTP_SUBDOMAIN_NAME_LENGTH * 8)
messageType = pcs.Field("messageType", 8)
sourceCommunicationTechnology = pcs.Field("sourceCommunicationTechnology", 8)
sourceUuid = pcs.StringField("sourceUuid", PTP_UUID_LENGTH * 8)
sourcePortId = pcs.Field("sourcePortId", 16)
sequenceId = pcs.Field("sequenceId", 16)
control = pcs.Field("control", 8, discriminator = True)
zero1 = pcs.Field("zero1", 8, default = 0)
flags = pcs.Field("flags", 16)
zero2 = pcs.Field("zero2", 32, default = 0)
pcs.Packet.__init__(self, [versionPTP, versionNetwork,
subdomain, messageType,
sourceCommunicationTechnology,
sourceUuid, sourcePortId, sequenceId,
control, zero1, flags, zero2],
bytes = bytes, **kv)
self.description = "initialize the common header "
if timestamp is None:
self.timestamp = time.time()
else:
self.timestamp = timestamp
if (bytes is not None):
self.data = self.next(bytes[self.sizeof():len(bytes)],
timestamp = timestamp)
else:
self.data = None
def __init__(self, bytes=None, timestamp=None, **kv):
""" Define the common IGMP encapsulation; see RFC 2236. """
type = pcs.Field("type", 8, discriminator=True)
code = pcs.Field("code", 8)
checksum = pcs.Field("checksum", 16)
pcs.Packet.__init__(self, [type, code, checksum], bytes=bytes, **kv)
self.description = "IGMP"
if timestamp is None:
self.timestamp = time.time()
else:
self.timestamp = timestamp
if bytes is not None:
offset = self.sizeof()
if self.type == IGMP_HOST_MEMBERSHIP_QUERY and \
len(bytes) >= igmpv3.IGMP_V3_QUERY_MINLEN:
self.data = igmpv3.query(bytes[offset:len(bytes)],
timestamp=timestamp)
else:
# XXX Workaround Packet.next() -- it only returns something
# if it can discriminate.
self.data = self.next(bytes[offset:len(bytes)],
timestamp=timestamp)
if self.data is None:
self.data = payload.payload(bytes[offset:len(bytes)])
else:
self.data = None
def test_tcp_with_options(self):
"""Assert that a TCP with options is correctly encoded."""
packet = tcp()
nop = pcs.Field("nop", 8)
mss = pcs.TypeLengthValueField("mss", pcs.Field("t", 8, default=0x02),
pcs.Field("l", 8), pcs.Field("v", 16))
end = pcs.Field("end", 8)
nop.value = 1
mss.value.value = 1460 # Most common Internet MSS value.
# Build a TCP option list which will be 32-bits aligned.
packet.options.append(nop)
packet.options.append(nop)
packet.options.append(mss)
packet.options.append(nop)
packet.options.append(end)
expected = "\x00\x00\x00\x00\x00\x00\x00\x00" \
"\x00\x00\x00\x00\x00\x00\x00\x00" \
"\x00\x00\x00\x00\x01\x01\x02\x04" \
"\x05\xb4\x01\x00"
got = packet.bytes
#packet.encode()
#hd = hexdumper()
#print hd.dump(expected)
#print hd.dump(got)
# XXX: Note well: just because you added an option list,
# doesn't mean the TCP option length is correct.
self.assertEqual(expected, got)
def __init__(self, bytes=None):
"""initialize a DNS query packet, which is a query for information"""
type = pcs.Field("type", 16)
qclass = pcs.Field("query_class", 16)
pcs.Packet.__init__(self, [type, qclass], bytes=bytes)
self.description = "DNS Query"
def __init__(self, bytes=None, timestamp=None, **kv):
"""Followup Header """
zero1 = pcs.Field("zero1", 16, default=0)
associatedSequenceId = pcs.Field("associatedSequenceId", 16)
preciseTimestampSeconds = pcs.Field("preciseTimestampSeconds", 32)
preciseTimestampNanoseconds = pcs.Field("preciseTimestampNanoseconds",
32)
pcs.Packet.__init__(self, [
zero1, associatedSequenceId, preciseTimestampSeconds,
preciseTimestampNanoseconds
],
bytes=bytes,
**kv)
self.description = "Followup Header "
if timestamp is None:
self.timestamp = time.time()
else:
self.timestamp = timestamp
if (bytes is not None):
self.data = self.next(bytes[self.sizeof():len(bytes)],
timestamp=timestamp)
else:
self.data = None
def __init__(self, bytes=None, timestamp=None, **kv):
ntpts = pcs.Field("ntpts", 64)
rtpts = pcs.Field("rtpts", 32)
spkts = pcs.Field("spkts", 32)
sbytes = pcs.Field("sbytes", 32)
opt = pcs.OptionListField("opt")
pcs.Packet.__init__(self, [ntpts, rtpts, spkts, sbytes, opt],
bytes=bytes,
**kv)
self.description = "RFC 3550 Real Time Control Protocol sender message portion"
if timestamp is None:
self.timestamp = time.time()
else:
self.timestamp = timestamp
if bytes is not None:
offset = self.sizeof()
curr = offset
remaining = len(bytes) - offset
# XXX TODO decapsulate all the report counts.
# to do this, we need to see the parent RC.
self.data = payload.payload(bytes[curr:remaining], \
timestamp = timestamp)
else:
self.data = None
def test_copy_lengthvaluefield(self):
"""Test shallow copy of LengthValueField. It contains two other
Fields, so a shallow copy should copy only those members."""
addr1 = inet_atol("192.0.2.1")
lf1 = pcs.Field("", 8)
vf1 = pcs.Field("", 32)
lvf1 = LengthValueField("lvf1", lf1, vf1)
self.assert_(isinstance(lvf1, pcs.LengthValueField))
self.assert_(isinstance(lvf1.length, pcs.Field))
self.assert_(isinstance(lvf1.value, pcs.Field))
self.assert_(id(lf1) == id(lvf1.length))
self.assert_(id(vf1) == id(lvf1.value))
vf1.value = addr1
self.assertEqual(lvf1.value.value, addr1, \
"lvf1's value-field value not set by assignment!")
lvf2 = copy(lvf1)
self.assertEqual(lvf2.packet, None, "lvf2.packet is not None!")
self.assert_(isinstance(lvf2, pcs.LengthValueField))
self.assert_(isinstance(lvf2.length, pcs.Field))
self.assert_(isinstance(lvf2.value, pcs.Field))
# Must be a shallow copy
self.assert_(id(lf1) == id(lvf2.length))
self.assert_(id(vf1) == id(lvf2.value))
self.assertEqual(lvf2.name, "lvf1", "lvf2's name not set by copy()!")
# Paranoia
self.assertEqual(lvf2.value.value, inet_atol("192.0.2.1"), \
"lvf2's value-field value differs!")
def __init__(self, bytes=None, timestamp=None, **kv):
""" Define the common rtmsg header; see <net/route.h>. """
msglen = pcs.Field("msglen", 16)
version = pcs.Field("version", 8, default=RTM_VERSION)
type = pcs.Field("type", 8, discriminator=True)
# XXX There's implicit padding all over the shop here.
pad0 = pcs.Field("type", 16)
pcs.Packet.__init__(self, [msglen, version, type, pad0], \
bytes = bytes, **kv)
self.description = " Define the common rtmsg header; see <net/route.h>. "
if timestamp is None:
self.timestamp = time.time()
else:
self.timestamp = timestamp
if bytes is not None:
# XXX Workaround Packet.next() -- it only returns something
# if it can discriminate.
# XXX Should try rtmsg next, next.
offset = self.sizeof()
self.data = self.next(bytes[offset:len(bytes)],
timestamp=timestamp)
if self.data is None:
self.data = payload.payload(bytes[offset:len(bytes)])
else:
self.data = None
def __init__(self, bytes=None):
"""Initialize a UDP packet for IPv6"""
sport = pcs.Field("sport", 16)
dport = pcs.Field("dport", 16)
length = pcs.Field("length", 16)
checksum = pcs.Field("checksum", 16)
pcs.Packet.__init__(self, [sport, dport, length, checksum], bytes)
def test_copy_typevaluefield(self):
"""Test shallow copy of TypeValueField."""
addr1 = inet_atol("192.0.2.1")
tf1 = pcs.Field("", 8)
vf1 = pcs.Field("", 32)
tvf1 = TypeValueField("tvf1", tf1, vf1)
self.assert_(isinstance(tvf1, pcs.TypeValueField))
self.assert_(isinstance(tvf1.type, pcs.Field))
self.assert_(isinstance(tvf1.value, pcs.Field))
self.assert_(id(tf1) == id(tvf1.type))
self.assert_(id(vf1) == id(tvf1.value))
tvf1.value.value = addr1
self.assertEqual(tvf1.value.value, addr1, \
"tvf1's value-field value not set by assignment!")
tvf2 = copy(tvf1)
self.assert_(id(tvf1) != id(tvf2))
self.assertEqual(tvf2.packet, None, "tvf2.packet is not None!")
self.assert_(isinstance(tvf2, pcs.TypeValueField))
self.assert_(isinstance(tvf2.type, pcs.Field))
self.assert_(isinstance(tvf2.value, pcs.Field))
# Must be a shallow copy
self.assert_(id(tf1) == id(tvf2.type))
self.assert_(id(vf1) == id(tvf2.value))
self.assertEqual(tvf2.name, "tvf1", \
"tvf2's name not set by copy()!")
# Paranoia
self.assertEqual(tvf2.value.value, inet_atol("192.0.2.1"), \
"tvf2's value-field value differs!")
def __init__(self, bytes=None, timestamp=None, **kv):
"""Delay Response"""
receiveTimestampSeconds = pcs.Field("receiveTimestampSeconds", 48)
receiveTimestampNanoSeconds = pcs.Field("receiveTimestampNanoSeconds",
32)
requestingPortIdentity = pcs.Field("requestingPortIdentity", 80)
pcs.Packet.__init__(self, [
receiveTimestampSeconds, receiveTimestampNanoSeconds,
requestingPortIdentity
],
bytes=bytes,
**kv)
self.description = "Delay Response "
if timestamp is None:
self.timestamp = time.time()
else:
self.timestamp = timestamp
if (bytes is not None):
self.data = self.next(bytes[self.sizeof():len(bytes)],
timestamp=timestamp)
else:
self.data = None
def __init__(self, bytes=None, timestamp=None, **kv):
u = pcs.Field("u", 1)
type = pcs.Field("exp", 15)
length = pcs.Field("length", 16)
id = pcs.Field("id", 32)
mparams = pcs.OptionListField("")
oparams = pcs.OptionListField("")
pcs.Packet.__init__(self, [ u, type, length, id, mparams, oparams ], \
bytes = bytes, **kv)
self.description = "RFC 3036 LDP message header "
if timestamp is None:
self.timestamp = time.time()
else:
self.timestamp = timestamp
if bytes is not None:
offset = self.sizeof()
curr = offset
remaining = len(bytes) - offset
self.data = payload.payload(bytes[curr:remaining], \
timestamp = timestamp)
else:
self.data = None
def __init__(self, bytes=None):
"""IPv6 destination options extension header from RFC 2460"""
global op
op = 0
next = pcs.Field("next_header", 8)
len = pcs.Field("length", 8)
type = pcs.Field("type", 8)
pcs.Packet.__init__(self, [next, len, type], bytes)
def __init__(self, bytes=None, timestamp=None):
"""IPv6 pseudo header from RFC 2460"""
src = pcs.StringField("src", 16 * 8)
dst = pcs.StringField("dst", 16 * 8)
length = pcs.Field("length", 32)
zero = pcs.Field("zero", 24)
nh = pcs.Field("next_header", 8)
pcs.Packet.__init__(self, [src, dst, length, zero, nh], bytes)
def test_deepcopy_typelengthvaluefield(self):
"""Test deep copy of TypeLengthValueField. It contains three other
Fields, so a deep copy should copy everything."""
addr1 = inet_atol("192.0.2.1")
tf1 = pcs.Field("", 8)
lf1 = pcs.Field("", 8)
vf1 = pcs.Field("", 32)
tlvf1 = TypeLengthValueField("tlvf1", tf1, lf1, vf1)
self.assert_(isinstance(tlvf1, pcs.TypeLengthValueField))
self.assert_(isinstance(tlvf1.type, pcs.Field))
self.assert_(isinstance(tlvf1.length, pcs.Field))
self.assert_(isinstance(tlvf1.value, pcs.Field))
self.assert_(id(tf1) == id(tlvf1.type))
self.assert_(id(lf1) == id(tlvf1.length))
self.assert_(id(vf1) == id(tlvf1.value))
tlvf1.value.value = addr1
self.assertEqual(tlvf1.value.value, addr1, \
"tlvf1's value-field value not set by assignment!")
addr2 = ether_atob("01:02:03:04:05:06")
tlvf2 = deepcopy(tlvf1)
self.assert_(id(tlvf1) != id(tlvf2))
self.assertEqual(tlvf2.packet, None, "tlvf2.packet is not None!")
self.assert_(isinstance(tlvf2, pcs.TypeLengthValueField))
self.assert_(isinstance(tlvf2.type, pcs.Field))
self.assert_(isinstance(tlvf2.length, pcs.Field))
self.assert_(isinstance(tlvf2.value, pcs.Field))
# Must be a deep copy
self.assert_(id(tf1) != id(tlvf2.type))
self.assert_(id(lf1) != id(tlvf2.length))
self.assert_(id(vf1) != id(tlvf2.value))
self.assertEqual(tlvf2.name, "tlvf1", \
"tlvf2's name not set by deepcopy()!")
# Paranoia
self.assertEqual(tlvf2.value.value, inet_atol("192.0.2.1"), \
"tlvf2's value-field value differs after deepcopy!")
tlvf1.value.value = inet_atol("192.0.2.2")
self.assertEqual(tlvf2.value.value, inet_atol("192.0.2.1"), \
"tlvf2's value-field value was changed by assignment to tvf1!")
tlvf2.type.value = 123
self.assertNotEqual(
tlvf1.type.value, tlvf2.type.value,
"tlvf2's type-field value does not differ after assignment!")
tlvf2.length.value = len(addr2)
self.assertNotEqual(
tlvf1.length.value, tlvf2.length.value,
"tlvf2's length-field value does not differ after assignment!")
tlvf2.value.value = addr2
self.assertNotEqual(
tlvf1.type.value, tlvf2.type.value,
"tvf2's type-field value does not differ after assignment!")
def _channel(n, x):
"""Given a tuple returned by struct.unpack(), produce a list
of decoded fields for a CHANNEL TLV."""
assert isinstance(n, str)
assert isinstance(x, tuple)
ret = []
ret += pcs.Field("chan_mhz", 8, default=x[0])
ret += pcs.Field("chan_flags", 8, default=x[1])
return ret
def __init__(self, bytes=None, timestamp=None, **kv):
"""initialize a Neighbor Solicitaion header"""
reserved = pcs.Field("reserved", 32)
target = pcs.Field("target", 128)
pcs.Packet.__init__(self, [reserved, target], bytes, **kv)
self.description = "initialize a Neighbor Solicitaion header"
if timestamp is None:
self.timestamp = time.time()
else:
self.timestamp = timestamp
def field(self):
""" Return the complete field value as it should be appended to
the DHCPv4 options payload. """
return pcs.TypeLengthValueField( \
self.fieldname(), \
pcs.Field("t", 8, default = self.optno), \
pcs.Field("l", 8, default = len(self.bytes)), \
self.datafield(), \
inclusive = False, \
bytewise = True)
def __init__(self, bytes=None, timestamp=None, **kv):
version = pcs.Field("version", 8)
type = pcs.Field("type", 8)
flags = pcs.Field("flags", 8)
root = pcs.StringField("root", 8 * 8)
cost = pcs.Field("cost", 32)
src = pcs.StringField("src", 8 * 8)
pid = pcs.Field("pid", 16)
age = pcs.Field("age", 16)
maxage = pcs.Field("maxage", 16)
interval = pcs.Field("interval", 16)
delay = pcs.Field("delay", 16)
#opt = pcs.OptionListField("opt")
pcs.Packet.__init__(self, [ version, type, flags, root, \
cost, src, pid, age, maxage, interval, \
delay ], bytes = bytes, **kv)
self.description = "IEEE 802.1d STP PDU"
if timestamp is None:
self.timestamp = time.time()
else:
self.timestamp = timestamp
if bytes is not None:
offset = self.sizeof()
curr = offset
remaining = len(bytes) - offset
# 802.1d shouldn't have any trailers.
self.data = payload.payload(bytes[curr:remaining], \
timestamp = timestamp)
else:
self.data = None
def __init__(self, bytes=None, timestamp=None, **kv):
""" Define the common RTNetlink message header."""
family = pcs.Field("family", 8)
dst_len = pcs.Field("dst_len", 8)
src_len = pcs.Field("src_len", 8)
tos = pcs.Field("tos", 8)
table = pcs.Field("table", 8)
protocol = pcs.Field("protocol", 8)
scope = pcs.Field("scope", 8)
type = pcs.Field("type", 8)
flags = pcs.Field("flags", 32)
#tlvs = pcs.OptionListField("tlvs")
pcs.Packet.__init__(self, [family, dst_len, src_len, tos, table, \
protocol, scope, type, flags], \
bytes = bytes, **kv)
self.description = " Define the common RTNetlink message header."
if timestamp is None:
self.timestamp = time.time()
else:
self.timestamp = timestamp
if bytes is not None:
offset = self.sizeof()
remaining = len(bytes) - offset
# TODO demux TLVs.
if self.data is None:
self.data = payload.payload(bytes[offset:remaining], \
timestamp=timestamp)
else:
self.data = None
def __init__(self, bytes = None, timestamp = None, **kv):
originTimestampSeconds = pcs.Field("originTimestampSeconds", 48)
originTimestampNanoSeconds = pcs.Field("originTimestampNanoSeconds", 32)
currentUTCOffset = pcs.Field("currentUTCOffset", 16)
reserved0 = pcs.Field("reserved0", 8, default = 0)
grandmasterPriority1 = pcs.Field("grandmasterPriority1", 8)
grandmasterClockQuality = pcs.Field("grandmasterClockQuality", 32)
grandmasterPriority2 = pcs.Field("grandmasterPriority2", 8)
grandmasterClockIdentity = pcs.StringField("grandmasterClockIdentity", 8)
stepsRemoved = pcs.Field("stepsRemoved", 16)
timeSource = pcs.Field("timeSource", 8)
pcs.Packet.__init__(self, [originTimestampSeconds,
originTimestampNanoSeconds,
currentUTCOffset,
reserved0,
grandmasterPriority1,
grandmasterClockQuality,
grandmasterPriority2,
grandmasterClockIdentity,
stepsRemoved,
timeSource], bytes = bytes, **kv)
self.description = "PTP Announce"
if timestamp is None:
self.timestamp = time.time()
else:
self.timestamp = timestamp
if (bytes is not None):
self.data = self.next(bytes[self.sizeof():len(bytes)],
timestamp = timestamp)
else:
self.data = None
def option(self, len=0):
"""add option header to the destination extension header"""
# XXX: pad0 option has not this header.
global op
op += 1
otype = pcs.Field("otype" + str(op), 8)
olen = pcs.Field("olength" + str(op), 8, default=len / 8)
if len != 0:
odata = pcs.Field("odata" + str(op), len)
pcs.Packet.__add__(self, [otype, olen, odata])
else:
pcs.Packet.__add__(self, [otype, olen])
def __init__(self, bytes=None):
"""initialize a DNS resource record, which encodes data returned from a query"""
name = pcs.LengthValueField("name", 8)
type = pcs.Field("type", 16)
qclass = pcs.Field("query_class", 16)
ttl = pcs.Field("ttl", 16)
rdata = pcs.LengthValueField("rdata", 16)
pcs.Packet.__init__(self, [name, type, qclass, ttl, rdata],
bytes=bytes)
self.description = "DNS Resource Record"