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pycrate/pycrate_corenet/HdlrENB.py

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# -*- coding: UTF-8 -*-
#/**
# * Software Name : pycrate
# * Version : 0.4
# *
# * Copyright 2017. Benoit Michau. ANSSI.
# *
# * This library is free software; you can redistribute it and/or
# * modify it under the terms of the GNU Lesser General Public
# * License as published by the Free Software Foundation; either
# * version 2.1 of the License, or (at your option) any later version.
# *
# * This library is distributed in the hope that it will be useful,
# * but WITHOUT ANY WARRANTY; without even the implied warranty of
# * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# * Lesser General Public License for more details.
# *
# * You should have received a copy of the GNU Lesser General Public
# * License along with this library; if not, write to the Free Software
# * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
# * MA 02110-1301 USA
# *
# *--------------------------------------------------------
# * File Name : pycrate_corenet/HdlrENB.py
# * Created : 2017-06-28
# * Authors : Benoit Michau
# *--------------------------------------------------------
#*/
from .utils import *
from .ProcCNS1ap import *
class ENBd(object):
"""eNB handler within a CorenetServer instance
responsible for S1AP signalling
"""
#--------------------------------------------------------------------------#
# debug and tracing level
#--------------------------------------------------------------------------#
#
# verbosity level
DEBUG = ('ERR', 'WNG', 'INF', 'DBG')
# to log S1AP PDU
TRACE_ASN_S1AP = False
# to keep track of all S1AP procedures
TRACK_PROC_S1AP = True
# Radio Access Technology remainder
RAT = RAT_EUTRA
# ID: (PLMN, CellID)
ID = (None, None)
# SCTP socket
SK = None
SKSid = 0
Addr = None
# Server reference
Server = None
def _log(self, logtype, msg):
"""ENBd logging facility
DEBUG logtype: 'ERR', 'WNG', 'INF', 'DBG'
TRACE logtype: 'TRACE_ASN_S1AP_[UL|DL]'
"""
if logtype[:3] == 'TRA':
log('[TRA] [ENB: %s.%s] [%s]\n%s%s%s'\
% (self.ID[0], self.ID[1], logtype[6:], TRACE_COLOR_START, msg, TRACE_COLOR_END))
elif logtype in self.DEBUG:
log('[%s] [ENB: %s.%s] %s' % (logtype, self.ID[0], self.ID[1], msg))
def __init__(self, server, sk, sid):
self.connect(server, sk, sid)
#
# init ENB config dict
self.Config = {}
# dict to link context-id -> UEd instance
self.UE = {}
# dict of warning message id -> warning message IEs
self.WARN = {}
#
# dict of ongoing S1AP procedures (indexed by their procedure code)
self.Proc = {}
# procedure code of the last procedure emitting a pdu toward the RAN
self.ProcLast = None
# list of tracked procedures (requires TRACK_PROC_S1AP = True)
self._proc = []
#
# counter for UE context id
self._ctx_id = 0
#--------------------------------------------------------------------------#
# network socket operations
#--------------------------------------------------------------------------#
def connect(self, server, sk, sid):
self.Server = server
self.SK = sk
self.SKSid = sid
self.Addr = sk.getpeername()
def disconnect(self):
del self.Server, self.SK, self.Addr, self.SKSid
def is_connected(self):
return self.SK is not None
#--------------------------------------------------------------------------#
# handling of non-UE-associated S1AP signalling procedures
#--------------------------------------------------------------------------#
def process_s1ap_pdu(self, pdu_rx):
"""process an S1AP PDU sent by the eNB for non-UE-associated signalling
and return a list of S1AP PDU(s) to be sent back to it
"""
errcause = None
if pdu_rx[0] == 'initiatingMessage':
# eNB-initiated procedure, instantiate it
try:
Proc = S1APNonUEProcEnbDispatcher[pdu_rx[1]['procedureCode']](self)
except Exception:
self._log('ERR', 'invalid S1AP PDU, initiatingMessage, code %i'\
% pdu_rx[1]['procedureCode'])
errcause = ('protocol', 'abstract-syntax-error-reject')
Proc = self.init_s1ap_proc(S1APErrorIndNonUECN, Cause=errcause)
else:
if self.TRACK_PROC_S1AP:
self._proc.append( Proc )
# process the PDU within the procedure
Proc.recv( pdu_rx )
if Proc.Class == 2 and Proc.errcause:
Err = self.init_s1ap_proc(S1APErrorIndNonUECN, Cause=Proc.errcause)
self.ProcLast = Err.Code
return Err.send()
elif Proc.Class == 1 or errcause:
self.ProcLast = Proc.Code
return Proc.send()
else:
pdu_tx = []
for ProcRet in Proc.trigger():
pdu_tx.extend( ProcRet.send() )
self.ProcLast = ProcRet.Code
return pdu_tx
#
else:
# CN-initiated procedure, transfer the PDU to it
try:
Proc = self.Proc[pdu_rx[1]['procedureCode']]
except Exception:
self._log('ERR', 'invalid S1AP PDU, %s, code %i'\
% (pdu_rx[0], pdu_rx[1]['procedureCode']))
errcause = ('protocol', 'message-not-compatible-with-receiver-state')
Proc = self.init_s1ap_proc(S1APErrorIndNonUECN, Cause=errcause)
# process the PDU within the procedure
Proc.recv( pdu_rx )
if Proc.errcause:
Err = self.init_s1ap_proc(S1APErrorIndNonUECN, Cause=Proc.errcause)
self.ProcLast = Err.Code
return Err.send()
elif errcause:
self.ProcLast = Proc.Code
return Proc.send()
else:
pdu_tx = []
for ProcRet in Proc.trigger():
pdu_tx.extend( ProcRet.send() )
self.ProcLast = ProcRet.Code
return pdu_tx
def init_s1ap_proc(self, ProcClass, **IEs):
"""initialize a CN-initiated S1AP procedure of class `ProcClass' for
non-UE-associated signalling, encode the initiatingMessage PDU with given
**IEs and return the procedure
"""
if not issubclass(ProcClass, S1APNonUESigProc):
self._log('WNG', 'initializing an invalid S1AP procedure, %s' % ProcClass.__name__)
if ProcClass.Code in self.Proc:
self._log('ERR', 'an S1AP procedure %s is already ongoing, unable to start a new one'\
% ProcClass.__name__)
return None
Proc = ProcClass(self)
if Proc.Code in S1APNonUEProcCnDispatcher and Proc.Class == 1:
# store the procedure, which requires a response from the eNB
self.Proc[Proc.Code] = Proc
if self.TRACK_PROC_S1AP:
# keep track of the procedure
self._proc.append( Proc )
Proc.encode_pdu('ini', **IEs)
return Proc
def start_s1ap_proc(self, ProcClass, **IEs):
"""initialize a CN-initiated S1AP procedure of class `ProcClass' for
non-UE-associated signalling, encode the initiatingMessage PDU with given
**IEs and send the PDU generated by the procedure to the eNB
"""
if not self.is_connected():
self._log('ERR', 'not connected')
return 0
Proc = self.init_s1ap_proc(ProcClass, **IEs)
if Proc is None:
return 0
self.ProcLast, cnt = Proc.Code, 0
for pdu_tx in Proc.send():
if self.Server.send_s1ap_pdu(self, pdu_tx, self.SKSid):
cnt += 1
return cnt
def get_s1setup_ies_from_cfg(self):
"""return the dict of IEs for the S1SetupResponse from the Config dict
"""
return {'MMEname' : self.Server.ConfigS1['MMEname'],
'RelativeMMECapacity': self.Server.ConfigS1['RelativeMMECapacity'],
'ServedGUMMEIs' : cplist(self.Server.ConfigS1['ServedGUMMEIs'])}
#--------------------------------------------------------------------------#
# handling of UE-associated S1AP signalling procedures
#--------------------------------------------------------------------------#
def process_s1ap_ue_pdu(self, pdu_rx, sid):
"""process an S1AP PDU sent by the eNB for UE-associated signalling with
a given SCTP stream id
and return a list of S1AP PDU(s) to be sent back to it
"""
if pdu_rx[0] == 'initiatingMessage' and pdu_rx[1]['procedureCode'] == 12:
# initialUEMessage, retrieve / create the UE instance
ue, ctx_id = self.get_ued(pdu_rx)
if ue is None:
self._log('ERR', 'unknown UE trying to connect')
errcause = ('protocol', 'abstract-syntax-error-reject')
Proc = self.init_s1ap_proc(S1APErrorIndNonUECN, Cause=errcause)
Proc.recv( pdu_rx )
self.ProcLast = Proc.Code
return Proc.send()
else:
self.set_ue_s1(ue, ctx_id)
try:
ue.set_ran(self, ctx_id, sid)
except Exception as err:
self._log('ERR', 'UE connected to several RAN, %r' % err)
return []
else:
ctx_id = self.get_enb_ue_ctx_id(pdu_rx)
if ctx_id is None:
self._log('ERR', 'no eNB UE context id provided')
errcause = ('protocol', 'abstract-syntax-error-reject')
Proc = self.init_s1ap_proc(S1APErrorIndNonUECN, Cause=errcause)
Proc.recv( pdu_rx )
self.ProcLast = Proc.Code
return Proc.send()
else:
try:
ue = self.UE[ctx_id]
except Exception:
self._log('ERR', 'invalid eNB UE context id provided')
errcause = ('radioNetwork', 'unknown-enb-ue-s1ap-id')
Proc = self.init_s1ap_proc(S1APErrorIndNonUECN, Cause=errcause)
Proc.recv( pdu_rx )
self.ProcLast = Proc.Code
return Proc.send()
else:
return ue.S1.process_s1ap_pdu(pdu_rx)
def set_ue_s1(self, ued, ctx_id):
self.UE[ctx_id] = ued
def unset_ue_s1(self, ctx_id):
try:
del self.UE[ctx_id]
except Exception:
self._log('WNG', 'no UE with S1 context-id %i to unset' % ctx_id)
def get_ued(self, pdu_rx):
enb_ue_id, nas_pdu, tai, s_tmsi = None, None, None, None
for ie in pdu_rx[1]['value'][1]['protocolIEs']:
if ie['id'] == 8:
# ENB-UE-S1AP-ID
enb_ue_id = ie['value'][1]
elif ie['id'] == 26:
# NAS-PDU
nas_pdu = ie['value'][1]
elif ie['id'] == 67:
# TAI
tai = ie['value'][1]
elif ie['id'] == 96:
# S-TMSI
s_tmsi = ie['value'][1]
if enb_ue_id is None or not nas_pdu or not tai:
# missing mandatory IE
return None, enb_ue_id
#plmn = plmn_buf_to_str(tai['pLMNidentity'])
if s_tmsi:
# use the S1AP S-TMSI
return self.Server.get_ued(mtmsi=bytes_to_uint(s_tmsi['m-TMSI'], 32)), enb_ue_id
else:
# use the EPSID within the NAS PDU
TS24007.IE.DECODE_INNER = False
NasRx, err = NAS.parse_NASLTE_MO(nas_pdu, inner=False)
TS24007.IE.DECODE_INNER = True
if err:
return None, enb_ue_id
sh = NasRx[0]['SecHdr'].get_val()
if sh in (1, 3):
TS24007.IE.DECODE_INNER = False
NasRx, err = NAS.parse_NASLTE_MO(NasRx['NASMessage'].get_val(), inner=False)
TS24007.IE.DECODE_INNER = True
if err:
return None, enb_ue_id
sh = NasRx[0]['SecHdr'].get_val()
if sh == 0:
# clear-text NAS PDU
if 'EPSID' in NasRx._by_name:
epsid = NasRx['EPSID'][-1].get_val()
elif 'OldGUTI' in NasRx._by_name:
epsid = NasRx['OldGUTI'][-1].get_val()
else:
return None, enb_ue_id
EpsId = NAS.EPSID()
EpsId.from_bytes(epsid)
ident = EpsId.decode()
if ident[0] == NAS.IDTYPE_IMSI:
return self.Server.get_ued(imsi=ident[1]), enb_ue_id
elif ident[0] == NAS.IDTYPE_GUTI:
# TODO: ensure PLMN, MME group, MMEC correspond
return self.Server.get_ued(mtmsi=ident[4]), enb_ue_id
else:
return None, enb_ue_id
else:
return None, enb_ue_id
def get_enb_ue_ctx_id(self, pdu_rx):
enb_ue_id = None
for ie in pdu_rx[1]['value'][1]['protocolIEs']:
if ie['id'] == 8:
# ENB-UE-S1AP-ID
enb_ue_id = ie['value'][1]
break
return enb_ue_id
#--------------------------------------------------------------------------#
# CN-initiated non-UE-associated S1AP signalling procedures
#--------------------------------------------------------------------------#
def page(self, **IEs):
"""start an S1APPaging toward the eNB
IEs should be set by the UE handler stack
"""
ret = self.start_s1ap_proc(S1APPaging, **IEs)
if not ret:
self._log('ERR', 'page: error')
return True if ret else False
def send_error_ind(self, cause, **IEs):
"""start a S1APErrorIndNonUECN with the given S1AP cause
IEs can contain any of the optional or extended IEs
"""
# send an S1APErrorInd to the eNB
IEs['Cause'] = cause
# send to the eNB
ret = self.start_s1ap_proc(S1APErrorIndNonUECN, **IEs)
if not ret:
self._log('ERR', 'send_error_ind: error')
return True if ret else False
def reset(self, reslist=None, cause=('misc', 115)):
"""start an S1APResetCN toward the eNB after having deleted some or all
UE-related S1 resources
If reslist is None, all UE-associated S1 resources will be reset
otherwise, reslist must be a list of UE context id to be reset
"""
# send an S1APResetCN to the eNB
IEs = {'Cause': cause}
if isinstance(reslist, (tuple, list)):
ue_res_list = []
for uectx in reslist:
if uectx in self.UE:
ue = self.UE[uectx]
ue.S1.unset_ran()
ue.S1.unset_ctx()
ue_res_list.append({
'id': 91,
'criticality': 'ignore',
'value': ('UE-associatedLogicalS1-ConnectionItem',
{'mME-UE-S1AP-ID': uectx,
'eNB-UE-S1AP-ID': uectx})})
else:
ue_res_list.append({
'id': 91,
'criticality': 'ignore',
'value': ('UE-associatedLogicalS1-ConnectionItem',
{'eNB-UE-S1AP-ID': uectx})})
IEs = {'ResetType': ('partOfS1-Interface', ue_res_list)}
else:
IEs = {'ResetType': ('s1-Interface', 'reset-all')}
# send to the eNB
ret = self.start_s1ap_proc(S1APResetCN, **IEs)
if not ret:
self._log('ERR', 'reset: error')
return True if ret else False
def bcast_warn_set(self, msgid, sernum, rep=10, num=10, **IEs):
"""set a warning message to be broacasted by the eNodeB, by using the
S1APWriteReplaceWarning procedure
In case of successful procedure, self.WARN is extended with the warning
message parameters
mandatory parameters:
msgid: uint16, type of warning message
sernum: uint16, unique identifier of the message for the given type
rep: 0..4095, repetition duration in sec
num: 0..65535, number of repetitions
IEs can contain:
- WarningAreaList
- WarningType
- WarningSecurityInfo
- DataCodingScheme
- WarningMessageContents
- ConcurrentWarningMessageIndicator
- ExtendedRepetitionPeriod
"""
#
IEs['MessageIdentifier'] = (msgid, 16)
IEs['SerialNumber'] = (sernum, 16)
IEs['RepetitionPeriod'] = rep
IEs['NumberofBroadcastRequest'] = num
#
ret = self.start_s1ap_proc(S1APWriteReplaceWarning, **IEs)
if not ret:
self._log('ERR', 'bcast_warn_set: error')
return True if ret else False
def bcast_warn_unset(self, msgid=None, sernum=0, **IEs):
"""disable a warning message broacasted by the eNodeB, by using the
S1APKill procedure
If msgid is None, all messages will be disabled, otherwise the given
message will be disabled
mandatory parameters:
msg: None or uint16, type of warning message
sernum: uint16, unique identifier of the message for the given type
IEs can contain:
WarningAreaList
"""
if msgid is None:
msgid, sernum = 0, 0
IEs['KillAllWarningMessages'] = 'true'
IEs['MessageIdentifier'] = (msgid, 16)
IEs['SerialNumber'] = (sernum, 16)
#
ret = self.start_s1ap_proc(S1APKill, **IEs)
if not ret:
self._log('ERR', 'bcast_warn_unset: error')
return False
else:
if IEs['KillAllWarningMessages'] == 'true':
self.WARN.clear()
else:
try:
del self.WARN[msgid]
except Exception:
pass
return True
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