class ICMPHeader(Header, PayloadMixin):
header_len = 4
@property
def type(self):
"""
The ICMP message type.
"""
return i(self.raw[0])
@type.setter
def type(self, val):
self.raw[0] = i(val)
@property
def code(self):
"""
The ICMP message code.
"""
return i(self.raw[1])
@code.setter
def code(self, val):
self.raw[1] = i(val)
cksum = raw_property('!H', 2, docs='The ICMP header checksum field.')
class UDPHeader(PseudoCksumHeaderMixin, PayloadMixin, PortMixin):
header_len = 8
@property
def payload(self):
return PayloadMixin.payload.fget(self)
@payload.setter
def payload(self, val):
PayloadMixin.payload.fset(self, val)
self.payload_len = len(val)
if not PY2 and not PY34:
payload.__doc__ = PayloadMixin.payload.__doc__
@property
def payload_len(self):
return struct.unpack_from("!H", self.raw, 4)[0] - 8
@payload_len.setter
def payload_len(self, val):
self.raw[4:6] = struct.pack("!H", val + 8)
cksum = raw_property('!H', 6, docs='The UDP header checksum field.')
class IPv4Header(IPHeader, PseudoCksumHeaderMixin):
_src_addr = slice(12, 16)
_dst_addr = slice(16, 20)
_af = socket.AF_INET
@property
def header_len(self):
"""
The IP header length in bytes.
"""
return self.hdr_len * 4
@property
def hdr_len(self):
"""
The header length in words of 32bit.
"""
return i(self.raw[0]) & 0x0F
@hdr_len.setter
def hdr_len(self, val):
if val < 5:
raise ValueError("IP header length must be greater or equal than 5.")
struct.pack_into('!B', self.raw, 0, 0x40 | val)
packet_len = raw_property('!H', 2, docs=IPHeader.packet_len.__doc__)
tos = raw_property('!B', 1, docs='The Type Of Service field (six-bit DiffServ field and a two-bit ECN field).')
ident = raw_property('!H', 4, docs='The Identification field.')
reserved = flag_property('reserved', 6, 0b10000000)
evil = flag_property('evil', 6, 0b10000000, docs='Just an april\'s fool joke for the RESERVED flag.')
df = flag_property('df', 6, 0b01000000)
mf = flag_property('mf', 6, 0b00100000)
ttl = raw_property('!B', 8, docs='The Time To Live field.')
protocol = raw_property('!B', 9, docs='The Protocol field.')
cksum = raw_property('!H', 10, docs='The IP header Checksum field.')
@property
def flags(self):
"""
The flags field: RESERVED (the evil bit), DF (don't fragment), MF (more fragments).
"""
return i(self.raw[6]) >> 5
@flags.setter
def flags(self, val):
struct.pack_into('!B', self.raw, 6, (val << 5) | (self.frag_offset & 0xFF00))
@property
def frag_offset(self):
"""
The Fragment Offset field in blocks of 8 bytes.
"""
return struct.unpack_from("!H", self.raw, 6)[0] & 0x1FFF
@frag_offset.setter
def frag_offset(self, val):
self.raw[6:8] = struct.pack("!H", (self.flags << 13) | (val & 0x1FFF))
@property
def dscp(self):
"""
The Differentiated Services Code Point field (originally defined as Type of Service) also known as DiffServ.
"""
return (i(self.raw[1]) >> 2) & 0x3F
@dscp.setter
def dscp(self, val):
struct.pack_into('!B', self.raw, 1, (val << 2) | self.ecn)
diff_serv = dscp
@property
def ecn(self):
"""
The Explicit Congestion Notification field.
"""
return i(self.raw[1]) & 0x03
@ecn.setter
def ecn(self, val):
struct.pack_into('!B', self.raw, 1, (self.dscp << 2) | (val & 0x03))
class IPv6Header(IPHeader):
_src_addr = slice(8, 24)
_dst_addr = slice(24, 40)
_af = socket.AF_INET6
header_len = 40
payload_len = raw_property('!H', 4, docs='The Payload Length field.')
next_hdr = raw_property('!B', 6, docs='The Next Header field. Replaces the Protocol field in IPv4.')
hop_limit = raw_property('!B', 7, docs='The Hop Limit field. Replaces the TTL field in IPv4.')
@property
def packet_len(self):
return self.payload_len + self.header_len
@packet_len.setter
def packet_len(self, val):
self.payload_len = val - self.header_len
@property
def traffic_class(self):
"""
The Traffic Class field (six-bit DiffServ field and a two-bit ECN field).
"""
return (struct.unpack_from('!H', self.raw, 0)[0] >> 4) & 0x00FF
@traffic_class.setter
def traffic_class(self, val):
struct.pack_into('!H', self.raw, 0, 0x6000 | (val << 4) | (self.flow_label & 0x000F0000))
@property
def flow_label(self):
"""
The Flow Label field.
"""
return struct.unpack_from('!I', self.raw, 0)[0] & 0x000FFFFF
@flow_label.setter
def flow_label(self, val):
struct.pack_into('!I', self.raw, 0, 0x60000000 | (self.traffic_class << 20) | (val & 0x000FFFFF))
@property
def diff_serv(self):
"""
The DiffServ field.
"""
return (self.traffic_class & 0xFC) >> 2
@diff_serv.setter
def diff_serv(self, val):
self.traffic_class = self.ecn | (val << 2)
@property
def ecn(self):
"""
The Explicit Congestion Notification field.
"""
return self.traffic_class & 0x03
@ecn.setter
def ecn(self, val):
self.traffic_class = (self.diff_serv << 2) | val
if not PY2 and not PY34:
packet_len.__doc__ = IPHeader.packet_len.__doc__
class TCPHeader(PseudoCksumHeaderMixin, PayloadMixin, PortMixin):
ns = flag_property("ns", 12, 0b00000001)
cwr = flag_property("cwr", 13, 0b10000000)
ece = flag_property("ece", 13, 0b01000000)
urg = flag_property("syn", 13, 0b00100000)
ack = flag_property("ack", 13, 0b00010000)
psh = flag_property("psh", 13, 0b00001000)
rst = flag_property("rst", 13, 0b00000100)
syn = flag_property("syn", 13, 0b00000010)
fin = flag_property("fin", 13, 0b00000001)
@property
def header_len(self):
"""
The TCP header length.
"""
return self.data_offset * 4
seq_num = raw_property('!I', 4, docs='The sequence number field.')
ack_num = raw_property('!I', 8, docs='The acknowledgement number field.')
window_size = raw_property('!H',
14,
docs='The size of the receive window in bytes.')
cksum = raw_property('!H', 16, docs='The TCP header checksum field.')
urg_ptr = raw_property('!H', 18, docs='The Urgent Pointer field.')
@property
def data_offset(self):
"""
The size of TCP header in 32bit words.
"""
return i(self.raw[12]) >> 4
@data_offset.setter
def data_offset(self, val):
if val < 5 or val > 15:
raise ValueError(
"TCP data offset must be greater or equal than 5 and less than 15."
)
struct.pack_into('!B', self.raw, 12,
(val << 4) | (self.reserved << 1) | self.ns)
@property
def reserved(self):
"""
The reserved field.
"""
return (i(self.raw[12]) >> 1) & 0x07
@reserved.setter
def reserved(self, val):
struct.pack_into('!B', self.raw, 12,
(self.data_offset << 4) | (val << 1) | self.ns)
@property
def control_bits(self):
"""
The Control Bits field.
"""
return struct.unpack_from('!H', self.raw, 12)[0] & 0x01FF
@control_bits.setter
def control_bits(self, val):
struct.pack_into('!H', self.raw, 12, (self.data_offset << 12) |
(self.reserved << 9) | (val & 0x01FF))