def ICMPExtension_post_dissection(self, pkt):
# RFC4884 section 5.2 says if the ICMP packet length
# is >144 then ICMP extensions start at byte 137.
lastlayer = pkt.lastlayer()
if not isinstance(lastlayer, conf.padding_layer):
return
if IP in pkt:
if (ICMP in pkt and pkt[ICMP].type in [3, 11, 12] and pkt.len > 144):
bytes = pkt[ICMP].build()[136:]
else:
return
elif scapy.layers.inet6.IPv6 in pkt:
if ((scapy.layers.inet6.ICMPv6TimeExceeded in pkt
or scapy.layers.inet6.ICMPv6DestUnreach in pkt)
and pkt.plen > 144):
bytes = pkt[scapy.layers.inet6.ICMPv6TimeExceeded].build()[136:]
else:
return
else:
return
# validate checksum
ieh = ICMPExtensionHeader(bytes)
if checksum(ieh.build()):
return # failed
lastlayer.load = lastlayer.load[:-len(ieh)]
lastlayer.add_payload(ieh)
def post_build(self, p, pay):
p += pay
if self.Length is None:
tmp_len = len(p)
tmp_p = p[:6] + chb((tmp_len >> 8) & 0xff) + chb(tmp_len & 0xff)
p = tmp_p + p[8:]
if self.chksum is None:
ck = checksum(p)
p = p[:2] + chb(ck >> 8) + chb(ck & 0xff) + p[4:]
return p
def post_build(self, p, pay):
p += pay
if self.Length is None:
tmp_len = len(p)
tmp_p = p[:6] + chb((tmp_len >> 8) & 0xff) + chb(tmp_len & 0xff)
p = tmp_p + p[8:]
if self.chksum is None:
ck = checksum(p)
p = p[:2] + chb(ck >> 8) + chb(ck & 0xff) + p[4:]
return p
def post_build(self, pkt, pay):
p = pkt + pay
if self.cksum is None:
cksum = checksum(self._check_len(p))
p = p[:2] + struct.pack("!H", cksum) + p[4:]
return p
def post_build(self, p, pay):
p += pay
if self.chksum is None:
c = checksum(p)
p = p[:2] + chb((c >> 8) & 0xff) + chb(c & 0xff) + p[4:]
return p
def post_build(self, p, pay):
if self.chksum is None:
ck = checksum(p)
p = p[:6] + chb(ck >> 8) + chb(ck & 0xff) + p[8:]
return p
def post_build(self, p, pay):
p += pay
if self.chksum is None:
c = checksum(p)
p = p[:2] + chb((c >> 8) & 0xff) + chb(c & 0xff) + p[4:]
return p
def post_build(self, pkt, pay):
p = pkt + pay
if self.cksum is None:
cksum = checksum(self._check_len(p))
p = p[:2] + struct.pack("!H", cksum) + p[4:]
return p
def post_build(self, p, pay):
if self.chksum is None:
ck = checksum(p)
p = p[:6] + chb(ck >> 8) + chb(ck & 0xff) + p[8:]
return p
