def _check_remote_ifid(self, pcb: PathSegment) -> Optional[ISD_AS]:
Requires(Acc(pcb.State(), 1 / 20))
Ensures(Acc(pcb.State(), 1 / 20))
"""
Checkes whether any PCB markings have unset remote IFID values for
up/downstream ASes. This can happen during normal startup depending
on the timing of PCB propagation vs IFID keep-alives, but should
not happen once the infrastructure is settled.
Remote IFID is only allowed to be 0 if the corresponding ISD-AS is
0-0.
"""
asms = pcb.iter_asms()
for asm in asms:
Invariant(Forall(asms, lambda a: (Acc(a.State(), 1 / 4), [])))
pcbms = asm.iter_pcbms()
for pcbm in pcbms:
Invariant(Forall(pcbms, lambda p: (Acc(p.State(), 1 / 4), [])))
if (pcbm.inIA().to_int() and not Unfolding(
Acc(pcbm.State(), 1 / 8),
Unfolding(Acc(pcbm.p.State(), 1 / 16), pcbm.p.inIF))):
return pcbm.inIA()
if (pcbm.outIA().to_int() and not Unfolding(
Acc(pcbm.State(), 1 / 8),
Unfolding(Acc(pcbm.p.State(), 1 / 16), pcbm.p.outIF))):
return pcbm.outIA()
return None
def check_filters(self, pcb: PathSegment) -> bool:
Requires(Acc(pcb.State(), 1 / 10))
Requires(Acc(self.State(), 1 / 7))
Requires(self.valid_ranges())
Ensures(Acc(pcb.State(), 1 / 10))
Ensures(Acc(self.State(), 1 / 7))
"""
Runs some checks, including: unwanted ASes and min/max property values.
:param pcb: beacon to analyze.
:type pcb: :class:`PathSegment`
:returns:
True if any unwanted AS is present or a range is not respected.
:rtype: bool
"""
assert isinstance(pcb, PathSegment)
isd_as = self._check_unwanted_ases(pcb)
if isd_as:
logging.warning("PathStore: pcb discarded, unwanted AS(%s): %s",
isd_as, pcb.short_desc())
return False
reasons = self._check_property_ranges(pcb)
if reasons:
logging.info("PathStore: pcb discarded(%s): %s",
", ".join(reasons), pcb.short_desc())
return False
ia = self._check_remote_ifid(pcb)
if ia:
logging.error(
"PathStore: pcb discarded, remote IFID of %s unknown", )
return False
return True
def _check_unwanted_ases(
self, pcb: PathSegment) -> Optional[ISD_AS]: # pragma: no cover
Requires(Acc(pcb.State(), 1 / 20))
Requires(Acc(self.State(), 1 / 8))
Ensures(Acc(pcb.State(), 1 / 20))
Ensures(Acc(self.State(), 1 / 8))
"""
Checks whether any of the ASes in the path belong to the black list.
:param pcb: beacon to analyze.
:type pcb: :class:`PathSegment`
"""
asms = pcb.iter_asms()
for asm in asms:
Invariant(Forall(asms, lambda a: (Acc(a.State(), 1 / 4), [])))
Invariant(Acc(self.State(), 1 / 9))
Invariant(Acc(pcb.State(), 1 / 20))
isd_as = asm.isd_as()
Unfold(Acc(self.State(), 1 / 10))
if isd_as in self.unwanted_ases:
Fold(Acc(self.State(), 1 / 10))
return isd_as
Fold(Acc(self.State(), 1 / 10))