def _update_fields(self):
if self.sum_au_active and self._changed():
# logger.debug(">>> IP: calculating sum")
# reset checksum for recalculation, mark as changed / clear cache
self.sum = 0
# logger.debug(">>> IP: bytes for sum: %s" % self.header_bytes)
self.sum = checksum.in_cksum(
packetracer.Packet.bin(self, update_auto_fields=True))
def _calc_sum(self):
try:
# we need src/dst for checksum-calculation
src, dst = self._lower_layer.src, self._lower_layer.dst
except Exception:
# not an IP packet as lower layer (src, dst not present) or invalid src/dst
# logger.debug("could not calculate checksum: %r" % e)
return
# pseudoheader
# packet length = length of upper layers
self.sum = 0
# logger.debug("TCP sum recalc: IP6= len(src)=%d\n%s\n%s\nhdr=%s\nbody=%s" %
# (len(src), src, dst, self.header_bytes, self.body_bytes))
pkt = self.header_bytes + self.body_bytes
hdr = pack_ipv6_icmp6(src, dst, len(pkt), 58)
# this will set the header status to changes, should be reset by calling bin()
self.sum = checksum.in_cksum(hdr + pkt)
def _update_fields(self):
if self.sum_au_active and self._changed():
self.sum = 0
self.sum = checksum.in_cksum(packetracer.Packet.bin(self))