def address_family(self):
"""
The packet address family:
- socket.AF_INET, if IPv4
- socket.AF_INET6, if IPv6
- None, otherwise.
"""
if len(self.raw) >= 20:
v = i(self.raw[0]) >> 4
if v == 4:
return socket.AF_INET
if v == 6:
return socket.AF_INET6
def address_family(self):
"""
The packet address family:
- socket.AF_INET, if IPv4
- socket.AF_INET6, if IPv6
- None, otherwise.
"""
if len(self.raw) >= 20:
v = i(self.raw[0]) >> 4
if v == 4:
return socket.AF_INET
if v == 6:
return socket.AF_INET6
def protocol(self):
"""
- | A (ipproto, proto_start) tuple.
| ``ipproto`` is the IP protocol in use, e.g. Protocol.TCP or Protocol.UDP.
| ``proto_start`` denotes the beginning of the protocol data.
| If the packet does not match our expectations, both ipproto and proto_start are None.
"""
if self.address_family == socket.AF_INET:
proto = i(self.raw[9])
start = (i(self.raw[0]) & 0b1111) * 4
elif self.address_family == socket.AF_INET6:
proto = i(self.raw[6])
# skip over well-known ipv6 headers
start = 40
while proto in IPV6_EXT_HEADERS:
if start >= len(self.raw):
# less than two bytes left
start = None
proto = None
break
if proto == Protocol.FRAGMENT:
hdrlen = 8
elif proto == Protocol.AH:
hdrlen = (i(self.raw[start + 1]) + 2) * 4
else:
# Protocol.HOPOPT, Protocol.DSTOPTS, Protocol.ROUTING
hdrlen = (i(self.raw[start + 1]) + 1) * 8
proto = i(self.raw[start])
start += hdrlen
else:
start = None
proto = None
out_of_bounds = ((proto == Protocol.TCP and start + 20 > len(self.raw))
or
(proto == Protocol.UDP and start + 8 > len(self.raw))
or (proto in {Protocol.ICMP, Protocol.ICMPV6}
and start + 4 > len(self.raw)))
if out_of_bounds:
# special-case tcp/udp so that we can rely on .protocol for the port properties.
start = None
proto = None
return proto, start
def protocol(self):
"""
- | A (ipproto, proto_start) tuple.
| ``ipproto`` is the IP protocol in use, e.g. Protocol.TCP or Protocol.UDP.
| ``proto_start`` denotes the beginning of the protocol data.
| If the packet does not match our expectations, both ipproto and proto_start are None.
"""
if self.address_family == socket.AF_INET:
proto = i(self.raw[9])
start = (i(self.raw[0]) & 0b1111) * 4
elif self.address_family == socket.AF_INET6:
proto = i(self.raw[6])
# skip over well-known ipv6 headers
start = 40
while proto in IPV6_EXT_HEADERS:
if start >= len(self.raw):
# less than two bytes left
start = None
proto = None
break
if proto == Protocol.FRAGMENT:
hdrlen = 8
elif proto == Protocol.AH:
hdrlen = (i(self.raw[start + 1]) + 2) * 4
else:
# Protocol.HOPOPT, Protocol.DSTOPTS, Protocol.ROUTING
hdrlen = (i(self.raw[start + 1]) + 1) * 8
proto = i(self.raw[start])
start += hdrlen
else:
start = None
proto = None
out_of_bounds = (
(proto == Protocol.TCP and start + 20 > len(self.raw)) or
(proto == Protocol.UDP and start + 8 > len(self.raw)) or
(proto in {Protocol.ICMP, Protocol.ICMPV6} and start + 4 > len(self.raw))
)
if out_of_bounds:
# special-case tcp/udp so that we can rely on .protocol for the port properties.
start = None
proto = None
return proto, start
def reserved(self):
"""
The reserved field.
"""
return (i(self.raw[12]) >> 1) & 0x07
def ecn(self):
"""
The Explicit Congestion Notification field.
"""
return i(self.raw[1]) & 0x03
def hdr_len(self):
"""
The header length in words of 32bit.
"""
return i(self.raw[0]) & 0x0F
def type(self, val):
self.raw[0] = i(val)
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
def ecn(self):
"""
The Explicit Congestion Notification field.
"""
return i(self.raw[1]) & 0x03
def code(self):
"""
The ICMP message code.
"""
return i(self.raw[1])
def data_offset(self):
"""
The size of TCP header in 32bit words.
"""
return i(self.raw[12]) >> 4
def flags(self):
"""
The flags field: RESERVED (the evil bit), DF (don't fragment), MF (more fragments).
"""
return i(self.raw[6]) >> 5
def code(self, val):
self.raw[1] = i(val)
def code(self):
"""
The ICMP message code.
"""
return i(self.raw[1])
def type(self, val):
self.raw[0] = i(val)
def type(self):
"""
The ICMP message type.
"""
return i(self.raw[0])
def code(self, val):
self.raw[1] = i(val)
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
def data_offset(self):
"""
The size of TCP header in 32bit words.
"""
return i(self.raw[12]) >> 4
def hdr_len(self):
"""
The header length in words of 32bit.
"""
return i(self.raw[0]) & 0x0F
def reserved(self):
"""
The reserved field.
"""
return (i(self.raw[12]) >> 1) & 0x07
def flags(self):
"""
The flags field: RESERVED (the evil bit), DF (don't fragment), MF (more fragments).
"""
return i(self.raw[6]) >> 5
def type(self):
"""
The ICMP message type.
"""
return i(self.raw[0])
