def test_basic(self):
pth_seg_db = PathSegmentDB()
pth_seg_db._db = create_mock(['delete'])
pth_seg_db._db.return_value = "data1"
ntools.eq_(pth_seg_db.delete("data2"), DBResult.ENTRY_DELETED)
pth_seg_db._db.assert_called_once_with(id="data2")
pth_seg_db._db.delete.assert_called_once_with("data1")
def test(self):
inst = PathSegmentDB()
inst.delete = create_mock()
inst.delete.side_effect = (DBResult.ENTRY_DELETED, DBResult.NONE,
DBResult.ENTRY_DELETED)
# Call
ntools.eq_(inst.delete_all((0, 1, 2)), 2)
# Tests
assert_these_calls(inst.delete, [call(i) for i in (0, 1, 2)])
class PathServer(SCIONElement, metaclass=ABCMeta):
"""
The SCION Path Server.
"""
SERVICE_TYPE = PATH_SERVICE
MAX_SEG_NO = 5 # TODO: replace by config variable.
# ZK path for incoming PATHs
ZK_PATH_CACHE_PATH = "path_cache"
# ZK path for incoming REVs
ZK_REV_CACHE_PATH = "rev_cache"
# Max number of segments per propagation packet
PROP_LIMIT = 5
# Max number of segments per ZK cache entry
ZK_SHARE_LIMIT = 10
# Time to store revocations in zookeeper
ZK_REV_OBJ_MAX_AGE = HASHTREE_EPOCH_TIME
# TTL of segments in the queue for ZK (in seconds)
SEGS_TO_ZK_TTL = 10 * 60
def __init__(self,
server_id,
conf_dir,
spki_cache_dir=GEN_CACHE_PATH,
prom_export=None):
"""
:param str server_id: server identifier.
:param str conf_dir: configuration directory.
:param str prom_export: prometheus export address.
"""
super().__init__(server_id,
conf_dir,
spki_cache_dir=spki_cache_dir,
prom_export=prom_export)
self.config = self._load_as_conf()
down_labels = {
**self._labels, "type": "down"
} if self._labels else None
core_labels = {
**self._labels, "type": "core"
} if self._labels else None
self.down_segments = PathSegmentDB(max_res_no=self.MAX_SEG_NO,
labels=down_labels)
self.core_segments = PathSegmentDB(max_res_no=self.MAX_SEG_NO,
labels=core_labels)
# Dict of pending requests.
self.pending_req = defaultdict(
lambda: ExpiringDict(1000, PATH_REQ_TOUT))
self.pen_req_lock = threading.Lock()
self._request_logger = None
# Used when l/cPS doesn't have up/dw-path.
self.waiting_targets = defaultdict(list)
self.revocations = RevCache(labels=self._labels)
# A mapping from (hash tree root of AS, IFID) to segments
self.htroot_if2seg = ExpiringDict(1000,
self.config.revocation_tree_ttl)
self.htroot_if2seglock = Lock()
self.CTRL_PLD_CLASS_MAP = {
PayloadClass.PATH: {
PMT.IFSTATE_INFOS: self.handle_ifstate_infos,
PMT.REQUEST: self.path_resolution,
PMT.REPLY: self.handle_path_reply,
PMT.REG: self.handle_seg_recs,
PMT.REVOCATION: self._handle_revocation,
PMT.SYNC: self.handle_seg_recs,
},
PayloadClass.CERT: {
CertMgmtType.CERT_CHAIN_REQ: self.process_cert_chain_request,
CertMgmtType.CERT_CHAIN_REPLY: self.process_cert_chain_reply,
CertMgmtType.TRC_REPLY: self.process_trc_reply,
CertMgmtType.TRC_REQ: self.process_trc_request,
},
}
self.SCMP_PLD_CLASS_MAP = {
SCMPClass.PATH: {
SCMPPathClass.REVOKED_IF: self._handle_scmp_revocation,
},
}
self._segs_to_zk = ExpiringDict(1000, self.SEGS_TO_ZK_TTL)
self._revs_to_zk = ExpiringDict(1000, HASHTREE_EPOCH_TIME)
self._zkid = ZkID.from_values(self.addr.isd_as, self.id,
[(self.addr.host, self._port)])
self.zk = Zookeeper(self.topology.isd_as, PATH_SERVICE,
self._zkid.copy().pack(), self.topology.zookeepers)
self.zk.retry("Joining party", self.zk.party_setup)
self.path_cache = ZkSharedCache(self.zk, self.ZK_PATH_CACHE_PATH,
self._handle_paths_from_zk)
self.rev_cache = ZkSharedCache(self.zk, self.ZK_REV_CACHE_PATH,
self._rev_entries_handler)
self._init_request_logger()
def worker(self):
"""
Worker thread that takes care of reading shared paths from ZK, and
handling master election for core servers.
"""
worker_cycle = 1.0
start = SCIONTime.get_time()
while self.run_flag.is_set():
sleep_interval(start, worker_cycle, "cPS.worker cycle",
self._quiet_startup())
start = SCIONTime.get_time()
try:
self.zk.wait_connected()
self.path_cache.process()
self.rev_cache.process()
# Try to become a master.
ret = self.zk.get_lock(lock_timeout=0, conn_timeout=0)
if ret: # Either got the lock, or already had it.
if ret == ZK_LOCK_SUCCESS:
logging.info("Became master")
self.path_cache.expire(self.config.propagation_time * 10)
self.rev_cache.expire(self.ZK_REV_OBJ_MAX_AGE)
except ZkNoConnection:
logging.warning('worker(): ZkNoConnection')
pass
self._update_master()
self._propagate_and_sync()
self._handle_pending_requests()
self._update_metrics()
def _update_master(self):
pass
def _rev_entries_handler(self, raw_entries):
for raw in raw_entries:
rev_info = RevocationInfo.from_raw(raw)
try:
rev_info.validate()
except SCIONBaseError as e:
logging.warning("Failed to validate RevInfo from zk: %s\n%s",
e, rev_info.short_desc())
continue
self._remove_revoked_segments(rev_info)
def _add_rev_mappings(self, pcb):
"""
Add if revocation token to segment ID mappings.
"""
segment_id = pcb.get_hops_hash()
with self.htroot_if2seglock:
for asm in pcb.iter_asms():
hof = asm.pcbm(0).hof()
egress_h = (asm.p.hashTreeRoot, hof.egress_if)
self.htroot_if2seg.setdefault(egress_h, set()).add(segment_id)
ingress_h = (asm.p.hashTreeRoot, hof.ingress_if)
self.htroot_if2seg.setdefault(ingress_h, set()).add(segment_id)
@abstractmethod
def _handle_up_segment_record(self, pcb, **kwargs):
raise NotImplementedError
@abstractmethod
def _handle_down_segment_record(self, pcb, **kwargs):
raise NotImplementedError
@abstractmethod
def _handle_core_segment_record(self, pcb, **kwargs):
raise NotImplementedError
def _add_segment(self, pcb, seg_db, name, reverse=False):
res = seg_db.update(pcb, reverse=reverse)
if res == DBResult.ENTRY_ADDED:
self._add_rev_mappings(pcb)
logging.info("%s-Segment registered: %s", name, pcb.short_id())
return True
elif res == DBResult.ENTRY_UPDATED:
self._add_rev_mappings(pcb)
logging.debug("%s-Segment updated: %s", name, pcb.short_id())
return False
def handle_ifstate_infos(self, cpld, meta):
"""
Handles IFStateInfos.
:param IFStatePayload infos: The state info objects.
"""
pmgt = cpld.union
infos = pmgt.union
assert isinstance(infos, IFStatePayload), type(infos)
for info in infos.iter_infos():
if not info.p.active and info.p.revInfo:
rev_info = info.rev_info()
try:
rev_info.validate()
except SCIONBaseError as e:
logging.warning(
"Failed to validate IFStateInfo RevInfo from %s: %s\n%s",
meta, e, rev_info.short_desc())
continue
self._handle_revocation(CtrlPayload(PathMgmt(info.rev_info())),
meta)
def _handle_scmp_revocation(self, pld, meta):
rev_info = RevocationInfo.from_raw(pld.info.rev_info)
try:
rev_info.validate()
except SCIONBaseError as e:
logging.warning("Failed to validate SCMP RevInfo from %s: %s\n%s",
meta, e, rev_info.short_desc())
return
self._handle_revocation(CtrlPayload(PathMgmt(rev_info)), meta)
def _handle_revocation(self, cpld, meta):
"""
Handles a revocation of a segment, interface or hop.
:param rev_info: The RevocationInfo object.
"""
pmgt = cpld.union
rev_info = pmgt.union
assert isinstance(rev_info, RevocationInfo), type(rev_info)
# Validate before checking for presense in self.revocations, as that will trigger an assert
# failure if the rev_info is invalid.
try:
rev_info.validate()
except SCIONBaseError as e:
# Validation already done in the IFStateInfo and SCMP paths, so a failure here means
# it's from a CtrlPld.
logging.warning(
"Failed to validate CtrlPld RevInfo from %s: %s\n%s", meta, e,
rev_info.short_desc())
return
if rev_info in self.revocations:
return
logging.debug("Received revocation from %s: %s", meta,
rev_info.short_desc())
try:
rev_info.validate()
except SCIONBaseError as e:
logging.warning("Failed to validate RevInfo from %s: %s", meta, e)
return
if meta.ia[0] != self.addr.isd_as[0]:
logging.info(
"Dropping revocation received from a different ISD. Src: %s RevInfo: %s"
% (meta, rev_info.short_desc()))
return
self.revocations.add(rev_info)
self._revs_to_zk[rev_info] = rev_info.copy().pack(
) # have to pack copy
# Remove segments that contain the revoked interface.
self._remove_revoked_segments(rev_info)
# Forward revocation to other path servers.
self._forward_revocation(rev_info, meta)
def _remove_revoked_segments(self, rev_info):
"""
Try the previous and next hashes as possible astokens,
and delete any segment that matches
:param rev_info: The revocation info
:type rev_info: RevocationInfo
"""
if ConnectedHashTree.verify_epoch(
rev_info.p.epoch) != ConnectedHashTree.EPOCH_OK:
return
(hash01, hash12) = ConnectedHashTree.get_possible_hashes(rev_info)
if_id = rev_info.p.ifID
with self.htroot_if2seglock:
down_segs_removed = 0
core_segs_removed = 0
up_segs_removed = 0
for h in (hash01, hash12):
for sid in self.htroot_if2seg.pop((h, if_id), []):
if self.down_segments.delete(
sid) == DBResult.ENTRY_DELETED:
down_segs_removed += 1
if self.core_segments.delete(
sid) == DBResult.ENTRY_DELETED:
core_segs_removed += 1
if not self.topology.is_core_as:
if (self.up_segments.delete(sid) ==
DBResult.ENTRY_DELETED):
up_segs_removed += 1
logging.debug(
"Removed segments revoked by [%s]: UP: %d DOWN: %d CORE: %d" %
(rev_info.short_desc(), up_segs_removed, down_segs_removed,
core_segs_removed))
@abstractmethod
def _forward_revocation(self, rev_info, meta):
"""
Forwards a revocation to other path servers that need to be notified.
:param rev_info: The RevInfo object.
:param meta: The MessageMeta object.
"""
raise NotImplementedError
def _send_path_segments(self,
req,
req_id,
meta,
logger,
up=None,
core=None,
down=None):
"""
Sends path-segments to requester (depending on Path Server's location).
"""
up = up or set()
core = core or set()
down = down or set()
all_segs = up | core | down
if not all_segs:
logger.warning("No segments to send for request: %s from: %s" %
(req.short_desc(), meta))
return
revs_to_add = self._peer_revs_for_segs(all_segs)
recs = PathSegmentRecords.from_values(
{
PST.UP: up,
PST.CORE: core,
PST.DOWN: down
}, revs_to_add)
pld = PathSegmentReply.from_values(req.copy(), recs)
self.send_meta(CtrlPayload(PathMgmt(pld), req_id=req_id), meta)
logger.info("Sending PATH_REPLY with %d segment(s).", len(all_segs))
def _peer_revs_for_segs(self, segs):
"""Returns a list of peer revocations for segments in 'segs'."""
def _handle_one_seg(seg):
for asm in seg.iter_asms():
for pcbm in asm.iter_pcbms(1):
hof = pcbm.hof()
for if_id in [hof.ingress_if, hof.egress_if]:
rev_info = self.revocations.get((asm.isd_as(), if_id))
if rev_info:
revs_to_add.add(rev_info.copy())
return
revs_to_add = set()
for seg in segs:
_handle_one_seg(seg)
return list(revs_to_add)
def _handle_pending_requests(self):
rem_keys = []
# Serve pending requests.
with self.pen_req_lock:
for key in self.pending_req:
for req_key, (req, req_id, meta,
logger) in self.pending_req[key].items():
if self.path_resolution(CtrlPayload(PathMgmt(req),
req_id=req_id),
meta,
new_request=False,
logger=logger):
meta.close()
del self.pending_req[key][req_key]
if not self.pending_req[key]:
rem_keys.append(key)
for key in rem_keys:
del self.pending_req[key]
def _handle_paths_from_zk(self, raw_entries):
"""
Handles cached paths through ZK, passed as a list.
"""
for raw in raw_entries:
recs = PathSegmentRecords.from_raw(raw)
for type_, pcb in recs.iter_pcbs():
seg_meta = PathSegMeta(pcb,
self.continue_seg_processing,
type_=type_,
params={'from_zk': True})
self._process_path_seg(seg_meta)
if raw_entries:
logging.debug("Processed %s segments from ZK", len(raw_entries))
def handle_path_reply(self, cpld, meta):
pmgt = cpld.union
reply = pmgt.union
assert isinstance(reply, PathSegmentReply), type(reply)
self._handle_seg_recs(reply.recs(), cpld.req_id, meta)
def handle_seg_recs(self, cpld, meta):
pmgt = cpld.union
seg_recs = pmgt.union
self._handle_seg_recs(seg_recs, cpld.req_id, meta)
def _handle_seg_recs(self, seg_recs, req_id, meta):
"""
Handles paths received from the network.
"""
assert isinstance(seg_recs, PathSegmentRecords), type(seg_recs)
params = self._dispatch_params(seg_recs, meta)
# Add revocations for peer interfaces included in the path segments.
for rev_info in seg_recs.iter_rev_infos():
self.revocations.add(rev_info)
# Verify pcbs and process them
for type_, pcb in seg_recs.iter_pcbs():
seg_meta = PathSegMeta(pcb, self.continue_seg_processing, meta,
type_, params)
self._process_path_seg(seg_meta, req_id)
def continue_seg_processing(self, seg_meta):
"""
For every path segment(that can be verified) received from the network
or ZK this function gets called to continue the processing for the
segment.
The segment is added to pathdb and pending requests are checked.
"""
pcb = seg_meta.seg
logging.debug("Successfully verified PCB %s" % pcb.short_id())
type_ = seg_meta.type
params = seg_meta.params
self.handle_ext(pcb)
self._dispatch_segment_record(type_, pcb, **params)
self._handle_pending_requests()
def handle_ext(self, pcb):
"""
Handle beacon extensions.
"""
# Handle PCB extensions:
for asm in pcb.iter_asms():
pol = asm.routing_pol_ext()
if pol:
self.handle_routing_pol_ext(pol)
def handle_routing_pol_ext(self, ext):
# TODO(Sezer): Implement extension handling
logging.debug("Routing policy extension: %s" % ext)
def _dispatch_segment_record(self, type_, seg, **kwargs):
# Check that segment does not contain a revoked interface.
if not self._validate_segment(seg):
return
handle_map = {
PST.UP: self._handle_up_segment_record,
PST.CORE: self._handle_core_segment_record,
PST.DOWN: self._handle_down_segment_record,
}
handle_map[type_](seg, **kwargs)
def _validate_segment(self, seg):
"""
Check segment for revoked upstream/downstream interfaces.
:param seg: The PathSegment object.
:return: False, if the path segment contains a revoked upstream/
downstream interface (not peer). True otherwise.
"""
for asm in seg.iter_asms():
pcbm = asm.pcbm(0)
for if_id in [pcbm.hof().ingress_if, pcbm.hof().egress_if]:
rev_info = self.revocations.get((asm.isd_as(), if_id))
if rev_info:
logging.debug(
"Found revoked interface (%d, %s) in segment %s." %
(rev_info.p.ifID, rev_info.isd_as(), seg.short_desc()))
return False
return True
def _dispatch_params(self, pld, meta):
return {}
def _propagate_and_sync(self):
self._share_via_zk()
self._share_revs_via_zk()
def _gen_prop_recs(self, container, limit=PROP_LIMIT):
count = 0
pcbs = defaultdict(list)
while container:
try:
_, (type_, pcb) = container.popitem(last=False)
except KeyError:
continue
count += 1
pcbs[type_].append(pcb.copy())
if count >= limit:
yield (pcbs)
count = 0
pcbs = defaultdict(list)
if pcbs:
yield (pcbs)
@abstractmethod
def path_resolution(self,
path_request,
meta,
new_request=True,
logger=None):
"""
Handles all types of path request.
"""
raise NotImplementedError
def _handle_waiting_targets(self, pcb):
"""
Handle any queries that are waiting for a path to any core AS in an ISD.
"""
dst_ia = pcb.first_ia()
if not self.is_core_as(dst_ia):
logging.warning("Invalid waiting target, not a core AS: %s",
dst_ia)
return
self._send_waiting_queries(dst_ia[0], pcb)
def _send_waiting_queries(self, dst_isd, pcb):
targets = self.waiting_targets[dst_isd]
if not targets:
return
path = pcb.get_path(reverse_direction=True)
src_ia = pcb.first_ia()
while targets:
(seg_req, logger) = targets.pop(0)
meta = self._build_meta(ia=src_ia,
path=path,
host=SVCType.PS_A,
reuse=True)
req_id = mk_ctrl_req_id()
self.send_meta(CtrlPayload(PathMgmt(seg_req), req_id=req_id), meta)
logger.info("Waiting request (%s) sent to %s via %s [id: %016x]",
seg_req.short_desc(), meta, pcb.short_desc(), req_id)
def _share_via_zk(self):
if not self._segs_to_zk:
return
logging.info("Sharing %d segment(s) via ZK", len(self._segs_to_zk))
for pcb_dict in self._gen_prop_recs(self._segs_to_zk,
limit=self.ZK_SHARE_LIMIT):
seg_recs = PathSegmentRecords.from_values(pcb_dict)
self._zk_write(seg_recs.pack())
def _share_revs_via_zk(self):
if not self._revs_to_zk:
return
logging.info("Sharing %d revocation(s) via ZK", len(self._revs_to_zk))
while self._revs_to_zk:
try:
data = self._revs_to_zk.popitem(last=False)[1]
except KeyError:
continue
self._zk_write_rev(data)
def _zk_write(self, data):
hash_ = crypto_hash(data).hex()
try:
self.path_cache.store("%s-%s" % (hash_, SCIONTime.get_time()),
data)
except ZkNoConnection:
logging.warning("Unable to store segment(s) in shared path: "
"no connection to ZK")
def _zk_write_rev(self, data):
hash_ = crypto_hash(data).hex()
try:
self.rev_cache.store("%s-%s" % (hash_, SCIONTime.get_time()), data)
except ZkNoConnection:
logging.warning("Unable to store revocation(s) in shared path: "
"no connection to ZK")
def _init_request_logger(self):
"""
Initializes the request logger.
"""
self._request_logger = logging.getLogger("RequestLogger")
# Create new formatter to include the request in the log.
formatter = formatter = Rfc3339Formatter(
"%(asctime)s [%(levelname)s] (%(threadName)s) %(message)s "
"{id=%(id)s, from=%(from)s}")
add_formatter('RequestLogger', formatter)
def get_request_logger(self, req_id, meta):
"""
Returns a logger adapter for a request.
"""
# Create a logger for the request to log with context.
return logging.LoggerAdapter(self._request_logger, {
"id": req_id,
"from": str(meta)
})
def _init_metrics(self):
super()._init_metrics()
REQS_TOTAL.labels(**self._labels).inc(0)
REQS_PENDING.labels(**self._labels).set(0)
SEGS_TO_ZK.labels(**self._labels).set(0)
REVS_TO_ZK.labels(**self._labels).set(0)
HT_ROOT_MAPPTINGS.labels(**self._labels).set(0)
IS_MASTER.labels(**self._labels).set(0)
def _update_metrics(self):
"""
Updates all Gauge metrics. Subclass can update their own metrics but must
call the superclass' implementation.
"""
if not self._labels:
return
# Update pending requests metric.
# XXX(shitz): This could become a performance problem should there ever be
# a large amount of pending requests (>100'000).
total_pending = 0
with self.pen_req_lock:
for reqs in self.pending_req.values():
total_pending += len(reqs)
REQS_PENDING.labels(**self._labels).set(total_pending)
# Update SEGS_TO_ZK and REVS_TO_ZK metrics.
SEGS_TO_ZK.labels(**self._labels).set(len(self._segs_to_zk))
REVS_TO_ZK.labels(**self._labels).set(len(self._revs_to_zk))
# Update HT_ROOT_MAPPTINGS metric.
HT_ROOT_MAPPTINGS.labels(**self._labels).set(len(self.htroot_if2seg))
# Update IS_MASTER metric.
IS_MASTER.labels(**self._labels).set(int(self.zk.have_lock()))
def run(self):
"""
Run an instance of the Path Server.
"""
threading.Thread(target=thread_safety_net,
args=(self.worker, ),
name="PS.worker",
daemon=True).start()
threading.Thread(target=thread_safety_net,
args=(self._check_trc_cert_reqs, ),
name="Elem.check_trc_cert_reqs",
daemon=True).start()
super().run()
class LocalPathServer(PathServer):
"""
SCION Path Server in a non-core AS. Stores up-segments to the core and
registers down-segments with the CPS. Can cache segments learned from a CPS.
"""
def __init__(self, server_id, conf_dir):
"""
:param str server_id: server identifier.
:param str conf_dir: configuration directory.
"""
super().__init__(server_id, conf_dir)
# Sanity check that we should indeed be a local path server.
assert not self.topology.is_core_as, "This shouldn't be a core PS!"
# Database of up-segments to the core.
self.up_segments = PathSegmentDB(max_res_no=self.MAX_SEG_NO)
def _handle_up_segment_record(self, pcb, from_zk=False):
if not from_zk:
self._segs_to_zk.append((PST.UP, pcb))
if self._add_segment(pcb, self.up_segments, "Up"):
# Sending pending targets to the core using first registered
# up-segment.
self._handle_waiting_targets(pcb)
return set([(pcb.first_ia(), pcb.is_sibra())])
return set()
def _handle_down_segment_record(self, pcb, from_zk=None):
if self._add_segment(pcb, self.down_segments, "Down"):
return set([(pcb.last_ia(), pcb.is_sibra())])
return set()
def _handle_core_segment_record(self, pcb, from_zk=None):
if self._add_segment(pcb, self.core_segments, "Core"):
return set([(pcb.first_ia(), pcb.is_sibra())])
return set()
def _remove_revoked_segments(self, rev_info):
"""
Remove segments that contain a revoked interface. Checks 20 tokens in
case previous revocations were missed by the PS.
:param rev_info: The revocation info
:type rev_info: RevocationInfo
"""
rev_token = rev_info.rev_token
for _ in range(self.N_TOKENS_CHECK):
segments = self.iftoken2seg[rev_token]
while segments:
sid = segments.pop()
# Delete segment from DB.
self.up_segments.delete(sid)
self.down_segments.delete(sid)
self.core_segments.delete(sid)
if rev_token in self.iftoken2seg:
del self.iftoken2seg[rev_token]
rev_token = SHA256.new(rev_token).digest()
def path_resolution(self, pkt, new_request=True):
"""
Handle generic type of a path request.
"""
req = pkt.get_payload()
dst_ia = req.dst_ia()
if new_request:
logging.info("PATH_REQ received: %s", req.short_desc())
if dst_ia == self.addr.isd_as:
logging.warning("Dropping request: requested DST is local AS")
return False
up_segs = set()
core_segs = set()
down_segs = set()
# dst as==0 means any core AS in the specified ISD
if self.is_core_as(dst_ia) or dst_ia[1] == 0:
self._resolve_core(req, up_segs, core_segs)
else:
self._resolve_not_core(req, up_segs, core_segs, down_segs)
if (up_segs | core_segs | down_segs):
self._send_path_segments(pkt, up_segs, core_segs, down_segs)
return True
if new_request:
self._request_paths_from_core(req)
self.pending_req[(dst_ia, req.p.flags.sibra)].append(pkt)
else:
# That could happend when needed segment expired.
logging.warning("Handling pending request and needed seg "
"is missing. Shouldn't be here (too often).")
return False
def _resolve_core(self, req, up_segs, core_segs):
"""
Dst is core AS.
"""
dst_ia = req.dst_ia()
params = dst_ia.params()
params["sibra"] = req.p.flags.sibra
if dst_ia[0] == self.addr.isd_as[0]:
# Dst in local ISD. First check whether DST is a (super)-parent.
up_segs.update(self.up_segments(**params))
# Check whether dst is known core AS.
for cseg in self.core_segments(**params):
# Check do we have an up-seg that is connected to core_seg.
tmp_up_segs = self.up_segments(first_ia=cseg.last_ia(),
sibra=req.p.flags.sibra)
if tmp_up_segs:
up_segs.update(tmp_up_segs)
core_segs.add(cseg)
def _resolve_not_core(self, req, up_segs, core_segs, down_segs):
"""
Dst is regular AS.
"""
sibra = req.p.flags.sibra
# Check if there exists down-seg to DST.
for dseg in self.down_segments(last_ia=req.dst_ia(), sibra=sibra):
first_ia = dseg.first_ia()
if req.dst_ia()[0] == self.addr.isd_as[0]:
# Dst in local ISD. First try to find direct up-seg.
dir_up_segs = self.up_segments(first_ia=first_ia, sibra=sibra)
if dir_up_segs:
up_segs.update(dir_up_segs)
down_segs.add(dseg)
# Now try core segments that connect to down segment.
# PSz: it might make sense to start with up_segments instead.
for cseg in self.core_segments(first_ia=first_ia, sibra=sibra):
# And up segments that connect to core segment.
up_core_segs = self.up_segments(first_ia=cseg.last_ia(),
sibra=sibra)
if up_core_segs:
up_segs.update(up_core_segs)
core_segs.add(cseg)
down_segs.add(dseg)
def _request_paths_from_core(self, req):
"""
Try to request core PS for given target.
"""
up_segs = self.up_segments(sibra=req.p.flags.sibra)
if not up_segs:
logging.info('Pending target added for %s', req.short_desc())
# Wait for path to any local core AS
self.waiting_targets[self.addr.isd_as[0]].append(req)
return
# PSz: for multipath it makes sense to query with multiple core ASes
pcb = up_segs[0]
logging.info('Send request to core (%s) via %s', req.short_desc(),
pcb.short_desc())
path = pcb.get_path(reverse_direction=True)
req_pkt = self._build_packet(SVCType.PS,
payload=req.copy(),
path=path,
dst_ia=pcb.first_ia())
self._send_to_next_hop(req_pkt, path.get_fwd_if())
def test_not_present(self):
pth_seg_db = PathSegmentDB()
pth_seg_db._db = create_mock()
pth_seg_db._db.return_value = False
ntools.eq_(pth_seg_db.delete("data"), DBResult.NONE)
class PathServer(SCIONElement, metaclass=ABCMeta):
"""
The SCION Path Server.
"""
SERVICE_TYPE = PATH_SERVICE
MAX_SEG_NO = 5 # TODO: replace by config variable.
# ZK path for incoming PATHs
ZK_PATH_CACHE_PATH = "path_cache"
# ZK path for incoming REVs
ZK_REV_CACHE_PATH = "rev_cache"
# Max number of segments per propagation packet
PROP_LIMIT = 5
# Max number of segments per ZK cache entry
ZK_SHARE_LIMIT = 10
# Time to store revocations in zookeeper
ZK_REV_OBJ_MAX_AGE = HASHTREE_EPOCH_TIME
def __init__(self, server_id, conf_dir):
"""
:param str server_id: server identifier.
:param str conf_dir: configuration directory.
"""
super().__init__(server_id, conf_dir)
self.down_segments = PathSegmentDB(max_res_no=self.MAX_SEG_NO)
self.core_segments = PathSegmentDB(max_res_no=self.MAX_SEG_NO)
self.pending_req = defaultdict(list) # Dict of pending requests.
self.pen_req_lock = threading.Lock()
# Used when l/cPS doesn't have up/dw-path.
self.waiting_targets = defaultdict(list)
self.revocations = RevCache()
# A mapping from (hash tree root of AS, IFID) to segments
self.htroot_if2seg = ExpiringDict(1000, HASHTREE_TTL)
self.htroot_if2seglock = Lock()
self.CTRL_PLD_CLASS_MAP = {
PayloadClass.PATH: {
PMT.REQUEST: self.path_resolution,
PMT.REPLY: self.handle_path_segment_record,
PMT.REG: self.handle_path_segment_record,
PMT.REVOCATION: self._handle_revocation,
PMT.SYNC: self.handle_path_segment_record,
},
PayloadClass.CERT: {
CertMgmtType.CERT_CHAIN_REQ: self.process_cert_chain_request,
CertMgmtType.CERT_CHAIN_REPLY: self.process_cert_chain_reply,
CertMgmtType.TRC_REPLY: self.process_trc_reply,
CertMgmtType.TRC_REQ: self.process_trc_request,
},
}
self.SCMP_PLD_CLASS_MAP = {
SCMPClass.PATH: {
SCMPPathClass.REVOKED_IF: self._handle_scmp_revocation,
},
}
self._segs_to_zk = deque()
self._revs_to_zk = deque()
self._zkid = ZkID.from_values(self.addr.isd_as, self.id,
[(self.addr.host, self._port)])
self.zk = Zookeeper(self.topology.isd_as, PATH_SERVICE,
self._zkid.copy().pack(), self.topology.zookeepers)
self.zk.retry("Joining party", self.zk.party_setup)
self.path_cache = ZkSharedCache(self.zk, self.ZK_PATH_CACHE_PATH,
self._handle_paths_from_zk)
self.rev_cache = ZkSharedCache(self.zk, self.ZK_REV_CACHE_PATH,
self._rev_entries_handler)
def worker(self):
"""
Worker thread that takes care of reading shared paths from ZK, and
handling master election for core servers.
"""
worker_cycle = 1.0
start = SCIONTime.get_time()
was_master = False
while self.run_flag.is_set():
sleep_interval(start, worker_cycle, "cPS.worker cycle",
self._quiet_startup())
start = SCIONTime.get_time()
try:
self.zk.wait_connected()
self.path_cache.process()
self.rev_cache.process()
# Try to become a master.
is_master = self.zk.get_lock(lock_timeout=0, conn_timeout=0)
if is_master:
if not was_master:
logging.info("Became master")
self.path_cache.expire(self.config.propagation_time * 10)
self.rev_cache.expire(self.ZK_REV_OBJ_MAX_AGE)
was_master = True
else:
was_master = False
except ZkNoConnection:
logging.warning('worker(): ZkNoConnection')
pass
self._update_master()
self._propagate_and_sync()
self._handle_pending_requests()
def _update_master(self):
pass
def _rev_entries_handler(self, raw_entries):
for raw in raw_entries:
rev_info = RevocationInfo.from_raw(raw)
self._remove_revoked_segments(rev_info)
def _add_rev_mappings(self, pcb):
"""
Add if revocation token to segment ID mappings.
"""
segment_id = pcb.get_hops_hash()
with self.htroot_if2seglock:
for asm in pcb.iter_asms():
hof = asm.pcbm(0).hof()
egress_h = (asm.p.hashTreeRoot, hof.egress_if)
self.htroot_if2seg.setdefault(egress_h, set()).add(segment_id)
ingress_h = (asm.p.hashTreeRoot, hof.ingress_if)
self.htroot_if2seg.setdefault(ingress_h, set()).add(segment_id)
@abstractmethod
def _handle_up_segment_record(self, pcb, **kwargs):
raise NotImplementedError
@abstractmethod
def _handle_down_segment_record(self, pcb, **kwargs):
raise NotImplementedError
@abstractmethod
def _handle_core_segment_record(self, pcb, **kwargs):
raise NotImplementedError
def _add_segment(self, pcb, seg_db, name, reverse=False):
res = seg_db.update(pcb, reverse=reverse)
if res == DBResult.ENTRY_ADDED:
self._add_rev_mappings(pcb)
logging.info("%s-Segment registered: %s", name, pcb.short_desc())
return True
elif res == DBResult.ENTRY_UPDATED:
self._add_rev_mappings(pcb)
logging.debug("%s-Segment updated: %s", name, pcb.short_desc())
return False
def _handle_scmp_revocation(self, pld, meta):
rev_info = RevocationInfo.from_raw(pld.info.rev_info)
self._handle_revocation(rev_info, meta)
def _handle_revocation(self, rev_info, meta):
"""
Handles a revocation of a segment, interface or hop.
:param rev_info: The RevocationInfo object.
"""
assert isinstance(rev_info, RevocationInfo)
if not self._validate_revocation(rev_info):
return
if meta.ia[0] != self.addr.isd_as[0]:
logging.info("Dropping revocation received from a different ISD.")
return
if rev_info in self.revocations:
logging.debug("Already received revocation. Dropping...")
return False
self.revocations.add(rev_info)
logging.debug("Received revocation from %s:\n%s", meta.get_addr(),
rev_info)
self._revs_to_zk.append(rev_info.copy().pack()) # have to pack copy
# Remove segments that contain the revoked interface.
self._remove_revoked_segments(rev_info)
# Forward revocation to other path servers.
self._forward_revocation(rev_info, meta)
def _remove_revoked_segments(self, rev_info):
"""
Try the previous and next hashes as possible astokens,
and delete any segment that matches
:param rev_info: The revocation info
:type rev_info: RevocationInfo
"""
if not ConnectedHashTree.verify_epoch(rev_info.p.epoch):
return
(hash01, hash12) = ConnectedHashTree.get_possible_hashes(rev_info)
if_id = rev_info.p.ifID
with self.htroot_if2seglock:
down_segs_removed = 0
core_segs_removed = 0
up_segs_removed = 0
for h in (hash01, hash12):
for sid in self.htroot_if2seg.pop((h, if_id), []):
if self.down_segments.delete(
sid) == DBResult.ENTRY_DELETED:
down_segs_removed += 1
if self.core_segments.delete(
sid) == DBResult.ENTRY_DELETED:
core_segs_removed += 1
if not self.topology.is_core_as:
if (self.up_segments.delete(sid) ==
DBResult.ENTRY_DELETED):
up_segs_removed += 1
logging.info(
"Removed segments containing IF %d: "
"UP: %d DOWN: %d CORE: %d" %
(if_id, up_segs_removed, down_segs_removed, core_segs_removed))
@abstractmethod
def _forward_revocation(self, rev_info, meta):
"""
Forwards a revocation to other path servers that need to be notified.
:param rev_info: The RevInfo object.
:param meta: The MessageMeta object.
"""
raise NotImplementedError
def _send_path_segments(self, req, meta, up=None, core=None, down=None):
"""
Sends path-segments to requester (depending on Path Server's location).
"""
up = up or set()
core = core or set()
down = down or set()
all_segs = up | core | down
if not all_segs:
logging.warning("No segments to send")
return
revs_to_add = self._peer_revs_for_segs(all_segs)
pld = PathRecordsReply.from_values(
{
PST.UP: up,
PST.CORE: core,
PST.DOWN: down
}, revs_to_add)
self.send_meta(pld, meta)
logging.info(
"Sending PATH_REPLY with %d segment(s) to:%s "
"port:%s in response to: %s",
len(all_segs),
meta.get_addr(),
meta.port,
req.short_desc(),
)
def _peer_revs_for_segs(self, segs):
"""Returns a list of peer revocations for segments in 'segs'."""
def _handle_one_seg(seg):
for asm in seg.iter_asms():
for pcbm in asm.iter_pcbms(1):
hof = pcbm.hof()
for if_id in [hof.ingress_if, hof.egress_if]:
rev_info = self.revocations.get((asm.isd_as(), if_id))
if rev_info:
revs_to_add.add(rev_info.copy())
return
revs_to_add = set()
for seg in segs:
_handle_one_seg(seg)
return list(revs_to_add)
def _handle_pending_requests(self):
rem_keys = []
# Serve pending requests.
with self.pen_req_lock:
for key in self.pending_req:
to_remove = []
for req, meta in self.pending_req[key]:
if self.path_resolution(req, meta, new_request=False):
meta.close()
to_remove.append((req, meta))
# Clean state.
for req_meta in to_remove:
self.pending_req[key].remove(req_meta)
if not self.pending_req[key]:
rem_keys.append(key)
for key in rem_keys:
del self.pending_req[key]
def _handle_paths_from_zk(self, raw_entries):
"""
Handles cached paths through ZK, passed as a list.
"""
for raw in raw_entries:
recs = PathSegmentRecords.from_raw(raw)
for type_, pcb in recs.iter_pcbs():
seg_meta = PathSegMeta(pcb,
self.continue_seg_processing,
type_=type_,
params={'from_zk': True})
self.process_path_seg(seg_meta)
logging.debug("Processed %s segments from ZK", len(raw_entries))
def handle_path_segment_record(self, seg_recs, meta):
"""
Handles paths received from the network.
"""
params = self._dispatch_params(seg_recs, meta)
# Add revocations for peer interfaces included in the path segments.
for rev_info in seg_recs.iter_rev_infos():
self.revocations.add(rev_info)
# Verify pcbs and process them
for type_, pcb in seg_recs.iter_pcbs():
seg_meta = PathSegMeta(pcb, self.continue_seg_processing, meta,
type_, params)
self.process_path_seg(seg_meta)
def continue_seg_processing(self, seg_meta):
"""
For every path segment(that can be verified) received from the network
or ZK this function gets called to continue the processing for the
segment.
The segment is added to pathdb and pending requests are checked.
"""
pcb = seg_meta.seg
type_ = seg_meta.type
params = seg_meta.params
self._dispatch_segment_record(type_, pcb, **params)
self._handle_pending_requests()
def _dispatch_segment_record(self, type_, seg, **kwargs):
# Check that segment does not contain a revoked interface.
if not self._validate_segment(seg):
logging.debug("Not adding segment due to revoked interface:\n%s" %
seg.short_desc())
return
handle_map = {
PST.UP: self._handle_up_segment_record,
PST.CORE: self._handle_core_segment_record,
PST.DOWN: self._handle_down_segment_record,
}
handle_map[type_](seg, **kwargs)
def _validate_segment(self, seg):
"""
Check segment for revoked upstream/downstream interfaces.
:param seg: The PathSegment object.
:return: False, if the path segment contains a revoked upstream/
downstream interface (not peer). True otherwise.
"""
for asm in seg.iter_asms():
pcbm = asm.pcbm(0)
for if_id in [pcbm.p.inIF, pcbm.p.outIF]:
rev_info = self.revocations.get((asm.isd_as(), if_id))
if rev_info:
logging.debug("Found revoked interface (%d) in segment "
"%s." % (rev_info.p.ifID, seg.short_desc()))
return False
return True
def _dispatch_params(self, pld, meta):
return {}
def _propagate_and_sync(self):
self._share_via_zk()
self._share_revs_via_zk()
def _gen_prop_recs(self, queue, limit=PROP_LIMIT):
count = 0
pcbs = defaultdict(list)
while queue:
count += 1
type_, pcb = queue.popleft()
pcbs[type_].append(pcb.copy())
if count >= limit:
yield (pcbs)
count = 0
pcbs = defaultdict(list)
if pcbs:
yield (pcbs)
@abstractmethod
def path_resolution(self, path_request, meta, new_request):
"""
Handles all types of path request.
"""
raise NotImplementedError
def _handle_waiting_targets(self, pcb):
"""
Handle any queries that are waiting for a path to any core AS in an ISD.
"""
dst_ia = pcb.first_ia()
if not self.is_core_as(dst_ia):
logging.warning("Invalid waiting target, not a core AS: %s",
dst_ia)
return
self._send_waiting_queries(dst_ia[0], pcb)
def _send_waiting_queries(self, dst_isd, pcb):
targets = self.waiting_targets[dst_isd]
if not targets:
return
path = pcb.get_path(reverse_direction=True)
src_ia = pcb.first_ia()
while targets:
seg_req = targets.pop(0)
meta = self.DefaultMeta.from_values(ia=src_ia,
path=path,
host=SVCType.PS_A)
self.send_meta(seg_req, meta)
logging.info("Waiting request (%s) sent via %s",
seg_req.short_desc(), pcb.short_desc())
def _share_via_zk(self):
if not self._segs_to_zk:
return
logging.info("Sharing %d segment(s) via ZK", len(self._segs_to_zk))
for pcb_dict in self._gen_prop_recs(self._segs_to_zk,
limit=self.ZK_SHARE_LIMIT):
seg_recs = PathSegmentRecords.from_values(pcb_dict)
self._zk_write(seg_recs.pack())
def _share_revs_via_zk(self):
if not self._revs_to_zk:
return
logging.info("Sharing %d revocation(s) via ZK", len(self._revs_to_zk))
while self._revs_to_zk:
self._zk_write_rev(self._revs_to_zk.popleft())
def _zk_write(self, data):
hash_ = SHA256.new(data).hexdigest()
try:
self.path_cache.store("%s-%s" % (hash_, SCIONTime.get_time()),
data)
except ZkNoConnection:
logging.warning("Unable to store segment(s) in shared path: "
"no connection to ZK")
def _zk_write_rev(self, data):
hash_ = SHA256.new(data).hexdigest()
try:
self.rev_cache.store("%s-%s" % (hash_, SCIONTime.get_time()), data)
except ZkNoConnection:
logging.warning("Unable to store revocation(s) in shared path: "
"no connection to ZK")
def run(self):
"""
Run an instance of the Path Server.
"""
threading.Thread(target=thread_safety_net,
args=(self.worker, ),
name="PS.worker",
daemon=True).start()
super().run()
class PathServer(SCIONElement, metaclass=ABCMeta):
"""
The SCION Path Server.
"""
SERVICE_TYPE = PATH_SERVICE
MAX_SEG_NO = 5 # TODO: replace by config variable.
# ZK path for incoming PATHs
ZK_PATH_CACHE_PATH = "path_cache"
# Number of tokens the PS checks when receiving a revocation.
N_TOKENS_CHECK = 20
# Max number of segments per propagation packet
PROP_LIMIT = 5
# Max number of segments per ZK cache entry
ZK_SHARE_LIMIT = 10
def __init__(self, server_id, conf_dir):
"""
:param str server_id: server identifier.
:param str conf_dir: configuration directory.
"""
super().__init__(server_id, conf_dir)
self.down_segments = PathSegmentDB(max_res_no=self.MAX_SEG_NO)
self.core_segments = PathSegmentDB(max_res_no=self.MAX_SEG_NO)
self.pending_req = defaultdict(list) # Dict of pending requests.
# Used when l/cPS doesn't have up/dw-path.
self.waiting_targets = defaultdict(list)
self.revocations = ExpiringDict(1000, 300)
self.iftoken2seg = defaultdict(set)
self.CTRL_PLD_CLASS_MAP = {
PayloadClass.PATH: {
PMT.REQUEST: self.path_resolution,
PMT.REPLY: self.handle_path_segment_record,
PMT.REG: self.handle_path_segment_record,
PMT.REVOCATION: self._handle_revocation,
PMT.SYNC: self.handle_path_segment_record,
},
}
self._segs_to_zk = deque()
# Add more IPs here if we support dual-stack
name_addrs = "\0".join(
[self.id, str(SCION_UDP_PORT),
str(self.addr.host)])
self.zk = Zookeeper(self.topology.isd_as, PATH_SERVICE, name_addrs,
self.topology.zookeepers)
self.zk.retry("Joining party", self.zk.party_setup)
self.path_cache = ZkSharedCache(self.zk, self.ZK_PATH_CACHE_PATH,
self._cached_entries_handler)
def worker(self):
"""
Worker thread that takes care of reading shared paths from ZK, and
handling master election for core servers.
"""
worker_cycle = 1.0
start = SCIONTime.get_time()
while self.run_flag.is_set():
sleep_interval(start, worker_cycle, "cPS.worker cycle",
self._quiet_startup())
start = SCIONTime.get_time()
try:
self.zk.wait_connected()
self.path_cache.process()
# Try to become a master.
is_master = self.zk.get_lock(lock_timeout=0, conn_timeout=0)
if is_master:
self.path_cache.expire(self.config.propagation_time * 10)
except ZkNoConnection:
logging.warning('worker(): ZkNoConnection')
pass
self._update_master()
self._propagate_and_sync()
def _cached_entries_handler(self, raw_entries):
"""
Handles cached through ZK entries, passed as a list.
"""
count = 0
for raw in raw_entries:
recs = PathSegmentRecords.from_raw(raw)
for type_, pcb in recs.iter_pcbs():
count += 1
self._dispatch_segment_record(type_, pcb, from_zk=True)
if count:
logging.debug("Processed %s PCBs from ZK", count)
def _update_master(self):
pass
def _add_if_mappings(self, pcb):
"""
Add if revocation token to segment ID mappings.
"""
segment_id = pcb.get_hops_hash()
for asm in pcb.p.asms:
self.iftoken2seg[asm.pcbms[0].igRevToken].add(segment_id)
self.iftoken2seg[asm.egRevToken].add(segment_id)
for pm in asm.pcbms:
self.iftoken2seg[pm.igRevToken].add(segment_id)
@abstractmethod
def _handle_up_segment_record(self, pcb, **kwargs):
raise NotImplementedError
@abstractmethod
def _handle_down_segment_record(self, pcb, **kwargs):
raise NotImplementedError
@abstractmethod
def _handle_core_segment_record(self, pcb, **kwargs):
raise NotImplementedError
def _add_segment(self, pcb, seg_db, name, reverse=False):
res = seg_db.update(pcb, reverse=reverse)
if res == DBResult.ENTRY_ADDED:
self._add_if_mappings(pcb)
logging.info("%s-Segment registered: %s", name, pcb.short_desc())
return True
elif res == DBResult.ENTRY_UPDATED:
logging.debug("%s-Segment updated: %s", name, pcb.short_desc())
return False
def _handle_revocation(self, pkt):
"""
Handles a revocation of a segment, interface or hop.
:param pkt: The packet containing the revocation info.
:type pkt: PathMgmtPacket
"""
rev_info = pkt.get_payload()
assert isinstance(rev_info, RevocationInfo)
if hash(rev_info) in self.revocations:
logging.debug("Already received revocation. Dropping...")
return
else:
self.revocations[hash(rev_info)] = rev_info
logging.debug("Received revocation from %s:\n%s", pkt.addrs.src,
rev_info)
# Remove segments that contain the revoked interface.
self._remove_revoked_segments(rev_info)
def _remove_revoked_segments(self, rev_info):
"""
Remove segments that contain a revoked interface. Checks 20 tokens in
case previous revocations were missed by the PS.
:param rev_info: The revocation info
:type rev_info: RevocationInfo
"""
rev_token = rev_info.rev_token
for _ in range(self.N_TOKENS_CHECK):
rev_token = SHA256.new(rev_token).digest()
segments = self.iftoken2seg[rev_token]
while segments:
sid = segments.pop()
# Delete segment from DB.
self.down_segments.delete(sid)
self.core_segments.delete(sid)
if rev_token in self.iftoken2seg:
del self.iftoken2seg[rev_token]
def _send_to_next_hop(self, pkt, if_id):
"""
Sends the packet to the next hop of the given if_id.
:param if_id: The interface ID of the corresponding interface.
:type if_id: int.
"""
if if_id not in self.ifid2er:
logging.error("Unknown Interface ID: %d", if_id)
return
next_hop = self.ifid2er[if_id].addr
self.send(pkt, next_hop)
def _send_path_segments(self, pkt, up=None, core=None, down=None):
"""
Sends path-segments to requester (depending on Path Server's location).
"""
up = up or set()
core = core or set()
down = down or set()
if not (up | core | down):
logging.warning("No segments to send")
return
req = pkt.get_payload()
rep_pkt = pkt.reversed_copy()
rep_pkt.set_payload(
PathRecordsReply.from_values(
{
PST.UP: up,
PST.CORE: core,
PST.DOWN: down
}, ))
rep_pkt.addrs.src.host = self.addr.host
next_hop, port = self.get_first_hop(rep_pkt)
if next_hop is None:
logging.error("Next hop is None for Interface %s",
rep_pkt.path.get_fwd_if())
return
logging.info(
"Sending PATH_REPLY with %d segment(s) to:%s "
"port:%s in response to: %s",
len(up | core | down),
rep_pkt.addrs.dst,
rep_pkt.l4_hdr.dst_port,
req.short_desc(),
)
self.send(rep_pkt, next_hop, port)
def _handle_pending_requests(self, dst_ia, sibra):
to_remove = []
key = dst_ia, sibra
# Serve pending requests.
for pkt in self.pending_req[key]:
if self.path_resolution(pkt, new_request=False):
to_remove.append(pkt)
# Clean state.
for pkt in to_remove:
self.pending_req[key].remove(pkt)
if not self.pending_req[key]:
del self.pending_req[key]
def handle_path_segment_record(self, pkt):
seg_recs = pkt.get_payload()
params = self._dispatch_params(pkt)
added = set()
for type_, pcb in seg_recs.iter_pcbs():
added.update(self._dispatch_segment_record(type_, pcb, **params))
# Handling pending requests, basing on added segments.
for dst_ia, sibra in added:
self._handle_pending_requests(dst_ia, sibra)
def _dispatch_segment_record(self, type_, seg, **kwargs):
handle_map = {
PST.UP: self._handle_up_segment_record,
PST.CORE: self._handle_core_segment_record,
PST.DOWN: self._handle_down_segment_record,
}
return handle_map[type_](seg, **kwargs)
def _dispatch_params(self, pkt):
return {}
def _propagate_and_sync(self):
self._share_via_zk()
def _gen_prop_recs(self, queue, limit=PROP_LIMIT):
count = 0
pcbs = defaultdict(list)
while queue:
count += 1
type_, pcb = queue.popleft()
pcbs[type_].append(pcb.copy())
if count >= limit:
yield (pcbs)
count = 0
pcbs = defaultdict(list)
if pcbs:
yield (pcbs)
@abstractmethod
def path_resolution(self, path_request):
"""
Handles all types of path request.
"""
raise NotImplementedError
def _handle_waiting_targets(self, pcb, reverse=False):
"""
Handle any queries that are waiting for a path to any core AS in an ISD.
"""
dst_ia = pcb.first_ia()
if reverse:
dst_ia = pcb.last_ia()
if not self.is_core_as(dst_ia):
logging.warning("Invalid waiting target, not a core AS: %s",
dst_ia)
return
self._send_waiting_queries(dst_ia[0], pcb)
def _send_waiting_queries(self, dst_isd, pcb):
targets = self.waiting_targets[dst_isd]
if not targets:
return
path = pcb.get_path(reverse_direction=True)
src_ia = pcb.first_ia()
while targets:
seg_req = targets.pop(0)
req_pkt = self._build_packet(SVCType.PS,
dst_ia=src_ia,
path=path,
payload=seg_req)
self._send_to_next_hop(req_pkt, path.get_fwd_if())
logging.info("Waiting request (%s) sent via %s",
seg_req.short_desc(), pcb.short_desc())
def _share_via_zk(self):
if not self._segs_to_zk:
return
logging.info("Sharing %d segment(s) via ZK", len(self._segs_to_zk))
for pcb_dict in self._gen_prop_recs(self._segs_to_zk,
limit=self.ZK_SHARE_LIMIT):
seg_recs = PathSegmentRecords.from_values(pcb_dict)
self._zk_write(seg_recs.pack())
def _zk_write(self, data):
hash_ = SHA256.new(data).hexdigest()
try:
self.path_cache.store("%s-%s" % (hash_, SCIONTime.get_time()),
data)
except ZkNoConnection:
logging.warning("Unable to store segment(s) in shared path: "
"no connection to ZK")
def run(self):
"""
Run an instance of the Path Server.
"""
threading.Thread(target=thread_safety_net,
args=(self.worker, ),
name="PS.worker",
daemon=True).start()
super().run()
