class NSM(object):
"""
Neighbor State Machine
:param ism: ISM objects.
:param rtid: RouterID.
:param pkt: coming hello packet.
"""
def __init__(self, ism, rtid, pkt):
# OSPF neighbor information
self.state = NSM_STATE["NSM_Down"] # NSM status.
self._inactive_timer = None
self._dd_exstart_timer = None
self.lsr_resend_timer = None
self.dd_flags = 0 # DD bit flags. Slave or master.
self.dd_seqnum = 0 # DD Sequence Number.
# Last sent Database Description packet.
self.last_send = None # just the packet, not tuple
# Timestemp when last Database Description packet was sent
self.last_send_ts = 0 # not used
# Last received Database Description packet.
self.last_recv = tuple() # pattern: (ddseq, init, more, ms)
# LSA data.
self.ls_rxmt = list() # Link state retransmission list
self.db_sum = list() # Database summary list
self.ls_req = list() # Link state request list
self.ism = ism
self.rtid = rtid # neighbor router id
self.nsm = dict()
# Neighbor Information from Hello.
self.src = pkt["H"]["SRC"]
self.options = pkt["V"]["V"]["OPTS"]
self.priority = pkt["V"]["V"]["PRIO"]
self.d_router = pkt["V"]["V"]["DESIG"]
self.bd_router = pkt["V"]["V"]["BDESIG"]
# inactive timer is equal to dead interval
self.inactive_timer_interval = self.ism.dead_interval
self.ep = ExchangeProtocol(self)
self.fp = FloodProtocol(self)
# register all nsm events
for nsmEvent in NSM_EVENT.keys():
if nsmEvent == "NSM_PacketReceived":
self.nsm[nsmEvent] = self._hello_received
elif nsmEvent == "NSM_TwoWayReceived":
self.nsm[nsmEvent] = self._two_way_or_exstart
elif nsmEvent == "NSM_OneWayReceived":
self.nsm[nsmEvent] = self._init
elif nsmEvent == "NSM_NegotiationDone":
self.nsm[nsmEvent] = self._exchange
elif nsmEvent == "NSM_SeqNumberMismatch":
self.nsm[nsmEvent] = self._seq_mismatch_or_bad_lsr
elif nsmEvent == "NSM_ExchangeDone":
self.nsm[nsmEvent] = self._loading
elif nsmEvent == "NSM_BadLSReq":
self.nsm[nsmEvent] = self._seq_mismatch_or_bad_lsr
elif nsmEvent == "NSM_LoadingDone":
self.nsm[nsmEvent] = self._full
else:
continue
def fire(self, event):
self.nsm[event]()
def reset(self):
self.change_nsm_state("NSM_Down")
if self._dd_exstart_timer is not None:
self._dd_exstart_timer.stop()
del self._dd_exstart_timer
if self.lsr_resend_timer is not None:
self.lsr_resend_timer.stop()
del self.lsr_resend_timer
self._dd_exstart_timer = None
self.lsr_resend_timer = None
self.ls_req = list()
self.ls_rxmt = list()
self.db_sum = list()
self.last_recv = tuple()
self.last_send = None
self.last_send_ts = 0
# Delete all LSA in LSDB
self.ism.ai.oi.lsdb.empty_lsdb()
def dead(self):
neighborLock.acquire()
self.reset()
self.rtid = 0
self.src = 0
self.options = {"E": 0, "MC": 0, "L": 0, "NP": 0, "DC": 0, "O": 0, "DN": 0, "Q": 0}
self.priority = 0
self.d_router = 0
self.bd_router = 0
if self._inactive_timer is not None:
self._inactive_timer.stop()
del self._inactive_timer
self._inactive_timer = None
LOG.info("[ISM] Event: ISM_NeighborChange")
self.ism.fire("ISM_NeighborChange")
neighborLock.release()
def _hello_received(self):
if self.state == NSM_STATE["NSM_Down"]:
self.change_nsm_state("NSM_Init")
# start inactive timer
if self._inactive_timer is None or self._inactive_timer.is_stop():
self._inactive_timer = Timer(self.inactive_timer_interval, self.dead)
self._inactive_timer.start()
LOG.debug("[NSM] %s starts inactive timer." % util.int2ip(self.rtid))
else:
self._inactive_timer.reset()
else:
self._inactive_timer.reset()
def _attempt(self):
"""
Only for nbma network
"""
self.change_nsm_state("NSM_Attempt")
def _init(self):
if self.state == NSM_STATE["NSM_Init"]:
return
self.change_nsm_state("NSM_Init")
self.last_recv = tuple()
self.last_send = None
self.last_send_ts = 0
self.ls_req = list()
self.ls_rxmt = list()
self.db_sum = list()
if not self.lsr_resend_timer is None:
self.lsr_resend_timer.stop()
def _two_way_or_exstart(self):
# whether become adjacent in broadcast, rfc 10.4
if self.state == NSM_STATE["NSM_Init"] or self.state == NSM_STATE["NSM_TwoWay"]:
# need to make adjacency
if self.ism.bdrip == self.src or self.ism.drip == self.src or self.ism.link_type == "Point-to-Point":
self.change_nsm_state("NSM_ExStart")
# Generate dd_sum from each lsa list, and exception for virtual link and stub area.
# But as a probe, we need not to send dd_sum.
# start dd sync procedure
self.dd_seqnum = int(time.time())
self.dd_flags = 7 # set init bit, more bit, master bit
self._send_dd()
if self._dd_exstart_timer is None:
pass
elif self._dd_exstart_timer.is_stop():
del self._dd_exstart_timer
else:
self._dd_exstart_timer.stop()
del self._dd_exstart_timer
self._dd_exstart_timer = Timer(self.ism.rxmt_interval, self._send_dd)
self._dd_exstart_timer.start()
# do not need to make adjacency
else:
if self.state == NSM_STATE["NSM_Init"]:
# change to 2-way state
self.change_nsm_state("NSM_TwoWay")
else:
# stay in 2-way state
pass
def _exchange(self):
self.change_nsm_state("NSM_Exchange")
self._dd_exstart_timer.stop()
self.fp.set_ospf_header(self.ism.version, self.ism.area_id, self.ism.rid, self.ism.options)
self.ep.exchange()
def _loading(self):
self.change_nsm_state("NSM_Loading")
# start to send first lsr
if len(self.ls_req) != 0:
self._send_lsr(self.ls_req)
self.lsr_resend_timer = Timer(self.ism.rxmt_interval, self._send_lsr, self.ls_req)
self.lsr_resend_timer.start()
else:
self._full()
def _full(self):
self.change_nsm_state("NSM_Full")
def _seq_mismatch_or_bad_lsr(self):
LOG.warn("[NSM] %s sequence mismatch or bad LSR." % util.int2ip(self.rtid))
# make sure that all these are clear
self.ls_req = list()
self.ls_rxmt = list()
self.db_sum = list()
self.last_recv = tuple()
self.last_send = None
self.last_send_ts = 0
self.change_nsm_state("NSM_ExStart")
self.dd_flags = 7 # set init bit, more bit, master bit
self.dd_seqnum = int(time.time())
self._send_dd()
if self._dd_exstart_timer is None:
self._dd_exstart_timer = Timer(self.ism.rxmt_interval, self._send_dd)
self._dd_exstart_timer.start()
elif self._dd_exstart_timer.is_stop():
del self._dd_exstart_timer
self._dd_exstart_timer = Timer(self.ism.rxmt_interval, self._send_dd)
self._dd_exstart_timer.start()
else:
self._dd_exstart_timer.reset()
def _send_dd(self, lsa=None):
self.ep.set_ospf_header(self.ism.version, self.ism.area_id, self.ism.rid, self.ism.options)
self.ep.set_dd_options()
self.ep.send_dd(self.ep.gen_dd(lsa))
def _send_lsr(self, lsr):
self.ep.send_lsr(self.ep.gen_lsr(lsr))
def change_nsm_state(self, newstate):
LOG.info("[NSM] %s change state to %s." % (util.int2ip(self.rtid), newstate))
self.state = NSM_STATE[newstate]
class ExchangeProtocol(OspfProtocol):
def __init__(self, nsm):
OspfProtocol.__init__(self)
self.init = 0
self.more = 0
self.ms = 0
self._rls_last_dd_timer = None
self.nsm = nsm
self.dst = ALL_SPF_ROUTER # by default
if self.nsm.ism.link_type == 'Broadcast':
if self.nsm.ism.drip == self.nsm.src:
self.dst = util.int2ip(self.nsm.ism.drip)
if self.nsm.ism.bdrip == self.nsm.src:
self.dst = util.int2ip(self.nsm.ism.bdrip)
elif self.nsm.ism.link_type == 'Point-to-Point':
self.dst = util.int2ip(self.nsm.src)
else:
#TODO: if link type is virtual or others, set dst specific.
pass
#ospf socket
self._sock = OspfSock()
self._sock.bind(self.nsm.ism.ip_intf_addr)
def __del__(self):
self._sock.close()
def set_dd_options(self):
dolist = list(util.int2bin(self.nsm.dd_flags))
self.init, self.more, self.ms = dolist[-3], dolist[-2], dolist[-1]
def gen_dd(self, lsa=None):
#In dd packet, the mtu is 1500 by default, but in virtual link, mtu is must set to 0
#TODO: set virtual link mtu
dd = DBDesc(
mtu=self.nsm.ism.mtu,
ddoptions=self.nsm.dd_flags,
options=self.options,
ddseq=self.nsm.dd_seqnum,
)
#TODO: unimplemented to send probe's dd
if not lsa is None:
pass
ospf_packet = OSPF(
v=self.version,
type=2, # 2 for dd
area=self.area,
len=len(dd) + len(OSPF()),
router=self.rid,
data=dd)
return str(ospf_packet)
def check_dd(self, pkt):
"""
check received dd packet,
return True means the packet is handled correctly,
return False means the packet is not in right procedure
"""
seq = pkt['V']['V']['DDSEQ']
mss, i, m = pkt['V']['V']['MS'], pkt['V']['V']['INIT'], pkt['V']['V'][
'MORE']
r, mtu = pkt['V']['RID'], pkt['V']['V']['MTU']
opt = pkt['V']['V']['OPTS']
last_ospf_opt = self.nsm.options # save current ospf options
self.nsm.options = opt # update nsm ospf options
tmp_last_recv = None # save last recv packet
if self.nsm.last_recv != (seq, i, m, mss):
tmp_last_recv = self.nsm.last_recv
self.nsm.last_recv = (seq, i, m, mss)
#check mtu, if neighbor's mtu greater than our interface, drop it
if self.nsm.ism.mtu < mtu:
LOG.warn('[Exchange] Deny for bigger MTU.')
return False
if self.nsm.state == NSM_STATE[
'NSM_Down'] or self.nsm.state == NSM_STATE['NSM_Attempt']:
LOG.warn('[Exchange] Deny for inappropriate state.')
return False
elif self.nsm.state == NSM_STATE['NSM_Init']:
self.nsm.fire('NSM_TwoWayReceived')
return False
elif self.nsm.state == NSM_STATE['NSM_TwoWay']:
LOG.warn('[Exchange] Ignore for inappropriate state.')
return False
elif self.nsm.state == NSM_STATE['NSM_ExStart']:
#Negotiate DD exchange
if mss == 1 and m == 1 and i == 1 and r > self.rid:
self.init = 0
self.more = 1
self.ms = 0 # set myself slave, use master dd seq number
self.nsm.dd_seqnum = pkt['V']['V']['DDSEQ']
self.nsm.dd_flags = 4 * self.init + 2 * self.more + self.ms
LOG.info('[NSM] Event: NSM_NegotiationDone')
LOG.info('[NSM] We are slave.')
self.nsm.fire('NSM_NegotiationDone')
return True
elif mss == 0 and i == 0 and r < self.rid:
self.init = 0
self.more = 1
self.ms = 1 # set myself master, use my dd seq number
self.nsm.dd_seqnum += 1
self.nsm.dd_flags = 4 * self.init + 2 * self.more + self.ms
LOG.info('[NSM] Event: NSM_NegotiationDone')
LOG.info('[NSM] We are master.')
self.nsm.fire('NSM_NegotiationDone')
if m == 0:
self.nsm.fire('NSM_ExchangeDone')
return True
else:
LOG.warn('[Exchange] Ignore for inappropriate dd options.')
return False
if self.nsm.state == NSM_STATE['NSM_Exchange']:
if (seq, i, m, mss) == tmp_last_recv:
if self.ms == 1:
LOG.warn('[Exchange] Duplicate DD packet, drop as master.')
return False
else:
#retransmit the last send packet
LOG.warn(
'[Exchange] Duplicate DD packet, retransmit as slave.')
self.send_dd(self.nsm.last_send)
return False
#check whether master/slave bit match or init bit is set unexpected
if mss == self.ms or i == 1:
LOG.warn('[Exchange] DD packet wrong options.')
self.nsm.fire('NSM_SeqNumberMismatch')
return False
#check whether ospf option is as same as the last received ospf packet
if not last_ospf_opt is None:
if last_ospf_opt != pkt['V']['V']['OPTS']:
LOG.warn(
'[Exchange] DD packet OSPF options are not same as the last received packet.'
)
self.nsm.fire('NSM_SeqNumberMismatch')
return False
#new recv dd packet is not last recv dd packet, get its lsa header
if not self._get_lsa(pkt):
#if there's some thing wrong in lsa header, fire SeqNumMismatch
LOG.error('[Exchange] DD packet has wrong LSA header.')
self.nsm.fire('NSM_SeqNumberMismatch')
return False
#when more bit is 0, exchange stop, goto loading state
if m == 0:
if self.ms == 0: # If we are slave, send dd as reply.
self.nsm.dd_seqnum = seq
#all pass checked, send my dd to neighbor
self.exchange()
self.nsm.fire('NSM_ExchangeDone')
else:
#if probe is master, ddseq + 1; if slave, set ddseq to master ddseq
if self.ms == 1:
self.nsm.dd_seqnum += 1
else:
self.nsm.dd_seqnum = seq
#all pass checked, send my dd to neighbor
self.exchange()
return True
elif self.nsm.state == NSM_STATE[
'NSM_Loading'] or self.nsm.state == NSM_STATE['NSM_Full']:
#check whether ospf option is as same as the last received ospf packet
if not last_ospf_opt is None:
if last_ospf_opt != pkt['V']['V']['OPTS']:
LOG.warn(
'[Exchange] DD packet OSPF options are not same as the last received packet.'
)
self.nsm.fire('NSM_SeqNumberMismatch')
return False
#Unexpected init bit
if i == 1:
LOG.error('[Exchange] Unexpected init bit in DD packet.')
self.nsm.fire('NSM_SeqNumberMismatch')
return False
if self.ms == 1:
LOG.error('[Exchange] Duplicate DD packet, drop as master.')
return False
else:
#retransmit the last send packet
if self.nsm.last_send is None:
LOG.error('[Exchange] Cannot retransmit last DD packet.')
self.nsm.fire('NSM_SeqNumberMismatch')
return False
LOG.warn(
'[Exchange] Duplicate DD packet, retransmit as slave.')
self.send_dd(self.nsm.last_send)
return True
else:
pass
def send_dd(self, pkt):
if self.nsm.ism.link_type == 'Broadcast' and self.dst != self.nsm.ism.drip and self.dst != self.nsm.ism.bdrip:
if self.nsm.ism.drip == self.nsm.src:
self.dst = util.int2ip(self.nsm.ism.drip)
if self.nsm.ism.bdrip == self.nsm.src:
self.dst = util.int2ip(self.nsm.ism.bdrip)
self._sock.conn(self.dst)
LOG.info('[Exchange] Send DD to %s.' % self.dst)
self._sock.sendp(pkt)
self.nsm.ism.ai.oi.stat.send_dd_count += 1
self.nsm.ism.ai.oi.stat.total_send_packet_count += 1
if self.nsm.state == NSM_STATE[
'NSM_Loading'] or self.nsm.state == NSM_STATE['NSM_Full']:
self.nsm.last_send = pkt # save the last sent packet
#start a timer to wait dead interval to release the last recv packet
if self._rls_last_dd_timer is None or self._rls_last_dd_timer.is_stop(
):
self._rls_last_dd_timer = Timer(self.nsm.ism.dead_interval,
self._rls_last_dd,
once=True)
self._rls_last_dd_timer.start()
else:
self._rls_last_dd_timer.reset()
def _rls_last_dd(self):
LOG.debug('[Exchange] Release last send DD packet.')
self.nsm.last_send = None
def _get_lsa(self, pkt):
aid = pkt['V']['AID']
lsa_hdr_list = pkt['V']['V']['LSAS']
for lsah in lsa_hdr_list.keys():
tp, lsid, adv, seq = lsa_hdr_list[lsah]['T'],\
lsa_hdr_list[lsah]['LSID'],\
lsa_hdr_list[lsah]['ADVRTR'],\
lsa_hdr_list[lsah]['LSSEQNO'],\
#generate lsa key according to lsa type.
if tp == 5:
#check if a type-5 lsa into a stub area, return false
if self.nsm.ism.options['E'] == 0:
return False
lsakey = (tp, lsid, adv)
else:
lsakey = (tp, aid, lsid, adv)
lsalist = self.nsm.ism.ai.oi.lsdb.lookup_lsa_list(tp)
if not lsalist is None:
lsa = self.lookup_lsa(lsakey, lsalist)
if lsa is None:
self.nsm.ls_req.append(lsakey)
elif lsa['H']['LSSEQNO'] < seq:
#the lsa in dd is newer than lsa in the database
self.nsm.ls_req.append(lsakey)
else:
continue
#if did not find the lsa list
else:
LOG.error('[Exchange] Wrong LSA type in DD.')
return False
return True
def exchange(self):
#TODO: The probe always set more bit to 0 when exchange. Need to modify if we want to send probe's DD summary.
lsa = self.nsm.db_sum
tosend = lsa
self.more = 0 # set more bit 0
self.nsm.dd_flags = 4 * int(self.init) + 2 * int(self.more) + int(
self.ms)
LOG.debug('[Exchange] DD flag is %s.' % self.nsm.dd_flags)
self.send_dd(self.gen_dd(tosend))
def gen_lsr(self, rq):
pkts = []
maxlsa = 100
more = True
#In each LSR packet, it contains 100 lsa headers at max
while more:
if len(rq) - maxlsa > 0:
lsas, rq = rq[:maxlsa], rq[maxlsa:]
else:
lsas = rq
more = False
lsrdata = []
lsrlen = len(lsas) * len(LSR())
for r in lsas:
if r[0] == 5:
lsrdata.append(str(LSR(lstype=r[0], lsid=r[1], adv=r[2])))
else:
lsrdata.append(str(LSR(lstype=r[0], lsid=r[2], adv=r[3])))
ospf_packet = OSPF(
v=self.version,
type=3, # 3 for lsr
area=self.area,
len=lsrlen + len(OSPF()),
router=self.rid,
data=''.join(lsrdata))
pkts.append(str(ospf_packet))
return pkts
def send_lsr(self, pkts):
if self.nsm.ism.link_type == 'Broadcast' and self.dst != self.nsm.ism.drip and self.dst != self.nsm.ism.bdrip:
if self.nsm.ism.drip == self.nsm.src:
self.dst = util.int2ip(self.nsm.ism.drip)
if self.nsm.ism.bdrip == self.nsm.src:
self.dst = util.int2ip(self.nsm.ism.bdrip)
LOG.debug('[Exchange] Send LSR to %s.' % self.dst)
self._sock.conn(self.dst)
for p in pkts:
self._sock.sendp(p)
self.nsm.ism.ai.oi.stat.send_lsr_count += 1
self.nsm.ism.ai.oi.stat.total_send_packet_count += 1
def check_lsr(self, pkt):
"""
The probe doesn't need to receive LSR
"""
pass
class ExchangeProtocol(OspfProtocol):
def __init__(self, nsm):
OspfProtocol.__init__(self)
self.init = 0
self.more = 0
self.ms = 0
self._rls_last_dd_timer = None
self.nsm = nsm
self.dst = ALL_SPF_ROUTER # by default
if self.nsm.ism.link_type == 'Broadcast':
if self.nsm.ism.drip == self.nsm.src:
self.dst = util.int2ip(self.nsm.ism.drip)
if self.nsm.ism.bdrip == self.nsm.src:
self.dst = util.int2ip(self.nsm.ism.bdrip)
elif self.nsm.ism.link_type == 'Point-to-Point':
self.dst = util.int2ip(self.nsm.src)
else:
#TODO: if link type is virtual or others, set dst specific.
pass
#ospf socket
self._sock = OspfSock()
self._sock.bind(self.nsm.ism.ip_intf_addr)
def __del__(self):
self._sock.close()
def set_dd_options(self):
dolist = list(util.int2bin(self.nsm.dd_flags))
self.init, self.more, self.ms = dolist[-3], dolist[-2], dolist[-1]
def gen_dd(self, lsa=None):
#In dd packet, the mtu is 1500 by default, but in virtual link, mtu is must set to 0
#TODO: set virtual link mtu
dd = DBDesc(
mtu=self.nsm.ism.mtu,
ddoptions=self.nsm.dd_flags,
options=self.options,
ddseq=self.nsm.dd_seqnum,
)
#TODO: unimplemented to send probe's dd
if not lsa is None:
pass
ospf_packet = OSPF(
v=self.version,
type=2, # 2 for dd
area=self.area,
len=len(dd)+len(OSPF()),
router=self.rid,
data=dd
)
return str(ospf_packet)
def check_dd(self, pkt):
"""
check received dd packet,
return True means the packet is handled correctly,
return False means the packet is not in right procedure
"""
seq = pkt['V']['V']['DDSEQ']
mss, i, m = pkt['V']['V']['MS'], pkt['V']['V']['INIT'], pkt['V']['V']['MORE']
r, mtu = pkt['V']['RID'], pkt['V']['V']['MTU']
opt = pkt['V']['V']['OPTS']
last_ospf_opt = self.nsm.options # save current ospf options
self.nsm.options = opt # update nsm ospf options
tmp_last_recv = None # save last recv packet
if self.nsm.last_recv != (seq, i, m, mss):
tmp_last_recv = self.nsm.last_recv
self.nsm.last_recv = (seq, i, m, mss)
#check mtu, if neighbor's mtu greater than our interface, drop it
if self.nsm.ism.mtu < mtu:
LOG.warn('[Exchange] Deny for bigger MTU.')
return False
if self.nsm.state == NSM_STATE['NSM_Down'] or self.nsm.state == NSM_STATE['NSM_Attempt']:
LOG.warn('[Exchange] Deny for inappropriate state.')
return False
elif self.nsm.state == NSM_STATE['NSM_Init']:
self.nsm.fire('NSM_TwoWayReceived')
return False
elif self.nsm.state == NSM_STATE['NSM_TwoWay']:
LOG.warn('[Exchange] Ignore for inappropriate state.')
return False
elif self.nsm.state == NSM_STATE['NSM_ExStart']:
#Negotiate DD exchange
if mss == 1 and m == 1 and i == 1 and r > self.rid:
self.init = 0
self.more = 1
self.ms = 0 # set myself slave, use master dd seq number
self.nsm.dd_seqnum = pkt['V']['V']['DDSEQ']
self.nsm.dd_flags = 4 * self.init + 2 * self.more + self.ms
LOG.info('[NSM] Event: NSM_NegotiationDone')
LOG.info('[NSM] We are slave.')
self.nsm.fire('NSM_NegotiationDone')
return True
elif mss == 0 and i == 0 and r < self.rid:
self.init = 0
self.more = 1
self.ms = 1 # set myself master, use my dd seq number
self.nsm.dd_seqnum += 1
self.nsm.dd_flags = 4 * self.init + 2 * self.more + self.ms
LOG.info('[NSM] Event: NSM_NegotiationDone')
LOG.info('[NSM] We are master.')
self.nsm.fire('NSM_NegotiationDone')
if m == 0:
self.nsm.fire('NSM_ExchangeDone')
return True
else:
LOG.warn('[Exchange] Ignore for inappropriate dd options.')
return False
if self.nsm.state == NSM_STATE['NSM_Exchange']:
if (seq, i, m, mss) == tmp_last_recv:
if self.ms == 1:
LOG.warn('[Exchange] Duplicate DD packet, drop as master.')
return False
else:
#retransmit the last send packet
LOG.warn('[Exchange] Duplicate DD packet, retransmit as slave.')
self.send_dd(self.nsm.last_send)
return False
#check whether master/slave bit match or init bit is set unexpected
if mss == self.ms or i == 1:
LOG.warn('[Exchange] DD packet wrong options.')
self.nsm.fire('NSM_SeqNumberMismatch')
return False
#check whether ospf option is as same as the last received ospf packet
if not last_ospf_opt is None:
if last_ospf_opt != pkt['V']['V']['OPTS']:
LOG.warn('[Exchange] DD packet OSPF options are not same as the last received packet.')
self.nsm.fire('NSM_SeqNumberMismatch')
return False
#new recv dd packet is not last recv dd packet, get its lsa header
if not self._get_lsa(pkt):
#if there's some thing wrong in lsa header, fire SeqNumMismatch
LOG.error('[Exchange] DD packet has wrong LSA header.')
self.nsm.fire('NSM_SeqNumberMismatch')
return False
#when more bit is 0, exchange stop, goto loading state
if m == 0:
if self.ms == 0: # If we are slave, send dd as reply.
self.nsm.dd_seqnum = seq
#all pass checked, send my dd to neighbor
self.exchange()
self.nsm.fire('NSM_ExchangeDone')
else:
#if probe is master, ddseq + 1; if slave, set ddseq to master ddseq
if self.ms == 1:
self.nsm.dd_seqnum += 1
else:
self.nsm.dd_seqnum = seq
#all pass checked, send my dd to neighbor
self.exchange()
return True
elif self.nsm.state == NSM_STATE['NSM_Loading'] or self.nsm.state == NSM_STATE['NSM_Full']:
#check whether ospf option is as same as the last received ospf packet
if not last_ospf_opt is None:
if last_ospf_opt != pkt['V']['V']['OPTS']:
LOG.warn('[Exchange] DD packet OSPF options are not same as the last received packet.')
self.nsm.fire('NSM_SeqNumberMismatch')
return False
#Unexpected init bit
if i == 1:
LOG.error('[Exchange] Unexpected init bit in DD packet.')
self.nsm.fire('NSM_SeqNumberMismatch')
return False
if self.ms == 1:
LOG.error('[Exchange] Duplicate DD packet, drop as master.')
return False
else:
#retransmit the last send packet
if self.nsm.last_send is None:
LOG.error('[Exchange] Cannot retransmit last DD packet.')
self.nsm.fire('NSM_SeqNumberMismatch')
return False
LOG.warn('[Exchange] Duplicate DD packet, retransmit as slave.')
self.send_dd(self.nsm.last_send)
return True
else:
pass
def send_dd(self, pkt):
if self.nsm.ism.link_type == 'Broadcast' and self.dst != self.nsm.ism.drip and self.dst != self.nsm.ism.bdrip:
if self.nsm.ism.drip == self.nsm.src:
self.dst = util.int2ip(self.nsm.ism.drip)
if self.nsm.ism.bdrip == self.nsm.src:
self.dst = util.int2ip(self.nsm.ism.bdrip)
self._sock.conn(self.dst)
LOG.info('[Exchange] Send DD to %s.' % self.dst)
self._sock.sendp(pkt)
self.nsm.ism.ai.oi.stat.send_dd_count += 1
self.nsm.ism.ai.oi.stat.total_send_packet_count += 1
if self.nsm.state == NSM_STATE['NSM_Loading'] or self.nsm.state == NSM_STATE['NSM_Full']:
self.nsm.last_send = pkt # save the last sent packet
#start a timer to wait dead interval to release the last recv packet
if self._rls_last_dd_timer is None or self._rls_last_dd_timer.is_stop():
self._rls_last_dd_timer = Timer(self.nsm.ism.dead_interval, self._rls_last_dd, once=True)
self._rls_last_dd_timer.start()
else:
self._rls_last_dd_timer.reset()
def _rls_last_dd(self):
LOG.debug('[Exchange] Release last send DD packet.')
self.nsm.last_send = None
def _get_lsa(self, pkt):
aid = pkt['V']['AID']
lsa_hdr_list = pkt['V']['V']['LSAS']
for lsah in lsa_hdr_list.keys():
tp, lsid, adv, seq = lsa_hdr_list[lsah]['T'],\
lsa_hdr_list[lsah]['LSID'],\
lsa_hdr_list[lsah]['ADVRTR'],\
lsa_hdr_list[lsah]['LSSEQNO'],\
#generate lsa key according to lsa type.
if tp == 5:
#check if a type-5 lsa into a stub area, return false
if self.nsm.ism.options['E'] == 0:
return False
lsakey = (tp, lsid, adv)
else:
lsakey = (tp, aid, lsid, adv)
lsalist = self.nsm.ism.ai.oi.lsdb.lookup_lsa_list(tp)
if not lsalist is None:
lsa = self.lookup_lsa(lsakey, lsalist)
if lsa is None:
self.nsm.ls_req.append(lsakey)
elif lsa['H']['LSSEQNO'] < seq:
#the lsa in dd is newer than lsa in the database
self.nsm.ls_req.append(lsakey)
else:
continue
#if did not find the lsa list
else:
LOG.error('[Exchange] Wrong LSA type in DD.')
return False
return True
def exchange(self):
#TODO: The probe always set more bit to 0 when exchange. Need to modify if we want to send probe's DD summary.
lsa = self.nsm.db_sum
tosend = lsa
self.more = 0 # set more bit 0
self.nsm.dd_flags = 4 * int(self.init) + 2 * int(self.more) + int(self.ms)
LOG.debug('[Exchange] DD flag is %s.' % self.nsm.dd_flags)
self.send_dd(self.gen_dd(tosend))
def gen_lsr(self, rq):
pkts = []
maxlsa = 100
more = True
#In each LSR packet, it contains 100 lsa headers at max
while more:
if len(rq) - maxlsa > 0:
lsas, rq = rq[:maxlsa], rq[maxlsa:]
else:
lsas = rq
more = False
lsrdata = []
lsrlen = len(lsas) * len(LSR())
for r in lsas:
if r[0] == 5:
lsrdata.append(str(LSR(
lstype=r[0],
lsid=r[1],
adv=r[2]
)))
else:
lsrdata.append(str(LSR(
lstype=r[0],
lsid=r[2],
adv=r[3]
)))
ospf_packet = OSPF(
v=self.version,
type=3, # 3 for lsr
area=self.area,
len=lsrlen + len(OSPF()),
router=self.rid,
data=''.join(lsrdata)
)
pkts.append(str(ospf_packet))
return pkts
def send_lsr(self, pkts):
if self.nsm.ism.link_type == 'Broadcast' and self.dst != self.nsm.ism.drip and self.dst != self.nsm.ism.bdrip:
if self.nsm.ism.drip == self.nsm.src:
self.dst = util.int2ip(self.nsm.ism.drip)
if self.nsm.ism.bdrip == self.nsm.src:
self.dst = util.int2ip(self.nsm.ism.bdrip)
LOG.debug('[Exchange] Send LSR to %s.' % self.dst)
self._sock.conn(self.dst)
for p in pkts:
self._sock.sendp(p)
self.nsm.ism.ai.oi.stat.send_lsr_count += 1
self.nsm.ism.ai.oi.stat.total_send_packet_count += 1
def check_lsr(self, pkt):
"""
The probe doesn't need to receive LSR
"""
pass
class NSM(object):
"""
Neighbor State Machine
:param ism: ISM objects.
:param rtid: RouterID.
:param pkt: coming hello packet.
"""
def __init__(self, ism, rtid, pkt):
#OSPF neighbor information
self.state = NSM_STATE['NSM_Down'] # NSM status.
self._inactive_timer = None
self._dd_exstart_timer = None
self.lsr_resend_timer = None
self.dd_flags = 0 # DD bit flags. Slave or master.
self.dd_seqnum = 0 # DD Sequence Number.
#Last sent Database Description packet.
self.last_send = None # just the packet, not tuple
#Timestemp when last Database Description packet was sent
self.last_send_ts = 0 # not used
#Last received Database Description packet.
self.last_recv = tuple() # pattern: (ddseq, init, more, ms)
#LSA data.
self.ls_rxmt = list() # Link state retransmission list
self.db_sum = list() # Database summary list
self.ls_req = list() # Link state request list
self.ism = ism
self.rtid = rtid # neighbor router id
self.nsm = dict()
#Neighbor Information from Hello.
self.src = pkt['H']['SRC']
self.options = pkt['V']['V']['OPTS']
self.priority = pkt['V']['V']['PRIO']
self.d_router = pkt['V']['V']['DESIG']
self.bd_router = pkt['V']['V']['BDESIG']
#inactive timer is equal to dead interval
self.inactive_timer_interval = self.ism.dead_interval
self.ep = ExchangeProtocol(self)
self.fp = FloodProtocol(self)
#register all nsm events
for nsmEvent in NSM_EVENT.keys():
if nsmEvent == 'NSM_PacketReceived':
self.nsm[nsmEvent] = self._hello_received
elif nsmEvent == 'NSM_TwoWayReceived':
self.nsm[nsmEvent] = self._two_way_or_exstart
elif nsmEvent == 'NSM_OneWayReceived':
self.nsm[nsmEvent] = self._init
elif nsmEvent == 'NSM_NegotiationDone':
self.nsm[nsmEvent] = self._exchange
elif nsmEvent == 'NSM_SeqNumberMismatch':
self.nsm[nsmEvent] = self._seq_mismatch_or_bad_lsr
elif nsmEvent == 'NSM_ExchangeDone':
self.nsm[nsmEvent] = self._loading
elif nsmEvent == 'NSM_BadLSReq':
self.nsm[nsmEvent] = self._seq_mismatch_or_bad_lsr
elif nsmEvent == 'NSM_LoadingDone':
self.nsm[nsmEvent] = self._full
else:
continue
def fire(self, event):
self.nsm[event]()
def reset(self):
self.change_nsm_state('NSM_Down')
if self._dd_exstart_timer is not None:
self._dd_exstart_timer.stop()
del self._dd_exstart_timer
if self.lsr_resend_timer is not None:
self.lsr_resend_timer.stop()
del self.lsr_resend_timer
self._dd_exstart_timer = None
self.lsr_resend_timer = None
self.ls_req = list()
self.ls_rxmt = list()
self.db_sum = list()
self.last_recv = tuple()
self.last_send = None
self.last_send_ts = 0
#Delete all LSA in LSDB
self.ism.ai.oi.lsdb.empty_lsdb()
def dead(self):
neighborLock.acquire()
self.reset()
self.rtid = 0
self.src = 0
self.options = {'E': 0, 'MC': 0, 'L': 0, 'NP': 0, 'DC': 0, 'O': 0, 'DN': 0, 'Q': 0}
self.priority = 0
self.d_router = 0
self.bd_router = 0
if self._inactive_timer is not None:
self._inactive_timer.stop()
del self._inactive_timer
self._inactive_timer = None
LOG.info('[ISM] Event: ISM_NeighborChange')
self.ism.fire('ISM_NeighborChange')
neighborLock.release()
def _hello_received(self):
if self.state == NSM_STATE['NSM_Down']:
self.change_nsm_state('NSM_Init')
#start inactive timer
if self._inactive_timer is None or self._inactive_timer.is_stop():
self._inactive_timer = Timer(self.inactive_timer_interval, self.dead)
self._inactive_timer.start()
LOG.debug('[NSM] %s starts inactive timer.' % util.int2ip(self.rtid))
else:
self._inactive_timer.reset()
else:
self._inactive_timer.reset()
def _attempt(self):
"""
Only for nbma network
"""
self.change_nsm_state('NSM_Attempt')
def _init(self):
if self.state == NSM_STATE['NSM_Init']:
return
self.change_nsm_state('NSM_Init')
self.last_recv = tuple()
self.last_send = None
self.last_send_ts = 0
self.ls_req = list()
self.ls_rxmt = list()
self.db_sum = list()
if not self.lsr_resend_timer is None:
self.lsr_resend_timer.stop()
def _two_way_or_exstart(self):
#whether become adjacent in broadcast, rfc 10.4
if self.state == NSM_STATE['NSM_Init'] or self.state == NSM_STATE['NSM_TwoWay']:
#need to make adjacency
if self.ism.bdrip == self.src or self.ism.drip == self.src or self.ism.link_type == 'Point-to-Point':
self.change_nsm_state('NSM_ExStart')
#Generate dd_sum from each lsa list, and exception for virtual link and stub area.
#But as a probe, we need not to send dd_sum.
#start dd sync procedure
self.dd_seqnum = int(time.time())
self.dd_flags = 7 # set init bit, more bit, master bit
self._send_dd()
if self._dd_exstart_timer is None:
pass
elif self._dd_exstart_timer.is_stop():
del self._dd_exstart_timer
else:
self._dd_exstart_timer.stop()
del self._dd_exstart_timer
self._dd_exstart_timer = Timer(self.ism.rxmt_interval, self._send_dd)
self._dd_exstart_timer.start()
#do not need to make adjacency
else:
if self.state == NSM_STATE['NSM_Init']:
#change to 2-way state
self.change_nsm_state('NSM_TwoWay')
else:
#stay in 2-way state
pass
def _exchange(self):
self.change_nsm_state('NSM_Exchange')
self._dd_exstart_timer.stop()
self.fp.set_ospf_header(
self.ism.version,
self.ism.area_id,
self.ism.rid,
self.ism.options,
)
self.ep.exchange()
def _loading(self):
self.change_nsm_state('NSM_Loading')
#start to send first lsr
if len(self.ls_req) != 0:
self._send_lsr(self.ls_req)
self.lsr_resend_timer = Timer(self.ism.rxmt_interval, self._send_lsr, self.ls_req)
self.lsr_resend_timer.start()
else:
self._full()
def _full(self):
self.change_nsm_state('NSM_Full')
def _seq_mismatch_or_bad_lsr(self):
LOG.warn('[NSM] %s sequence mismatch or bad LSR.' % util.int2ip(self.rtid))
#make sure that all these are clear
self.ls_req = list()
self.ls_rxmt = list()
self.db_sum = list()
self.last_recv = tuple()
self.last_send = None
self.last_send_ts = 0
self.change_nsm_state('NSM_ExStart')
self.dd_flags = 7 # set init bit, more bit, master bit
self.dd_seqnum = int(time.time())
self._send_dd()
if self._dd_exstart_timer is None:
self._dd_exstart_timer = Timer(self.ism.rxmt_interval, self._send_dd)
self._dd_exstart_timer.start()
elif self._dd_exstart_timer.is_stop():
del self._dd_exstart_timer
self._dd_exstart_timer = Timer(self.ism.rxmt_interval, self._send_dd)
self._dd_exstart_timer.start()
else:
self._dd_exstart_timer.reset()
def _send_dd(self, lsa=None):
self.ep.set_ospf_header(
self.ism.version,
self.ism.area_id,
self.ism.rid,
self.ism.options,
)
self.ep.set_dd_options()
self.ep.send_dd(self.ep.gen_dd(lsa))
def _send_lsr(self, lsr):
self.ep.send_lsr(self.ep.gen_lsr(lsr))
def change_nsm_state(self, newstate):
LOG.info('[NSM] %s change state to %s.' % (util.int2ip(self.rtid), newstate))
self.state = NSM_STATE[newstate]
