From 11c791572c6c2bfdc06f0b77c36f601a118268f0 Mon Sep 17 00:00:00 2001 From: p1-bmu Date: Wed, 20 Oct 2021 12:29:04 +0200 Subject: [PATCH] GTP-U: complete rework of the Extension Headers --- pycrate_mobile/TS29281_GTPU.py | 362 ++++++++++++++------------------- 1 file changed, 148 insertions(+), 214 deletions(-) diff --git a/pycrate_mobile/TS29281_GTPU.py b/pycrate_mobile/TS29281_GTPU.py index 4101bbc..9ab9318 100644 --- a/pycrate_mobile/TS29281_GTPU.py +++ b/pycrate_mobile/TS29281_GTPU.py @@ -1,7 +1,7 @@ # -*- coding: UTF-8 -*- #/** # * Software Name : pycrate -# * Version : 0.4 +# * Version : 0.5 # * # * Copyright 2019. Benoit Michau. P1Sec. # * @@ -27,25 +27,15 @@ # *-------------------------------------------------------- #*/ - +''' __all__ = [ - # GTPU extension headers - 'GTPUHdrExtAuto', - 'GTPUHdrExt3', - 'GTPUHdrExt32', - 'GTPUHdrExt64', - 'GTPUHdrExt129', - 'GTPUHdrExt131', - 'GTPUHdrExt132', - 'GTPUHdrExt133', - 'GTPUHdrExt192', # GTPU Messages - 'GTPUMsg', 'GTPUEchoRequest', 'GTPUEchoResponse', 'GTPUErrorInd', 'GTPUSuppExtHdrNotif', 'GTPUEndMarker', + 'GTPUTunnelStatus', 'GPDU', # GTPU Message parser and associated errors 'parse_GTPU', @@ -53,7 +43,7 @@ __all__ = [ 'ERR_GTPU_BUF_INVALID', 'ERR_GTPU_TYPE_NONEXIST' ] - +''' #------------------------------------------------------------------------------# # 3GPP TS 29.281: General Packet Radio System (GPRS) Tunnelling Protocol @@ -74,12 +64,12 @@ from pycrate_core.base import * #------------------------------------------------------------------------------# GTPUNextExtHeader_dict = { - 0 : 'No more extension headers', - 1 : 'Reserved - Control Plane only', - 2 : 'Reserved - Control Plane only', - 3 : 'Long PDCP PDU Number', - 32 : 'Service Class Indicator', - 64 : 'UDP source port of the triggering message', + 0 : 'No more extension headers', + 1 : 'Reserved - Control Plane only', + 2 : 'Reserved - Control Plane only', + 3 : 'Long PDCP PDU Number', + 32 : 'Service Class Indicator', + 64 : 'UDP source port of the triggering message', 129 : 'RAN Container', 130 : 'Long PDCP PDU Number', 131 : 'Xw RAN Container', @@ -90,28 +80,10 @@ GTPUNextExtHeader_dict = { 194 : 'Reserved - Control Plane only' } -# non-automated base class -class GTPUHdrExt(Envelope): - _ID = 0xff - _GEN = ( - Uint8('Len'), - Buf('Content'), - Uint8('NextExt', dic=GTPUNextExtHeader_dict) - ) - - def __init__(self, *args, **kwargs): - Envelope.__init__(self, *args, **kwargs) - self[-1].set_valauto(lambda: self._get_next_hdr()) - - def _get_next_hdr(self): - n = self.get_next() - if n and hasattr(n, '_ID'): - return n._ID - else: - return 0 - +# buffer that makes the Ext Header 32-bit-aligned class BufAligned(Buf): + PAD = b'\0' def set_val(self, val): @@ -122,135 +94,107 @@ class BufAligned(Buf): Buf.set_val(self, val) -# automated base class -class GTPUHdrExtAuto(GTPUHdrExt): - _ID = 0xff +# prototype for the content of a generic Ext Header +class _GTPUHdrExtCont(Envelope): _GEN = ( + BufAligned('Value', val=b'\0\0', rep=REPR_HEX), + ) + + _ID = 1 + + def __init__(self, *args, **kwargs): + if 'ID' in kwargs: + self._ID = kwargs['ID'] + del kwargs['ID'] + Envelope.__init__(self, *args, **kwargs) + + def clone(self): + c = Envelope.clone(self) + c._ID = self._ID + return c + + +class _LongPDCPPDUNumber(_GTPUHdrExtCont): + _GEN = ( + Uint('spare', bl=6, rep=REPR_HEX), + Uint('Value', bl=18), + Uint24('spare', rep=REPR_HEX), + ) + + +# All defined Ext Header +GTPUHdrExtCont_dict = { + 3 : _LongPDCPPDUNumber('LongPDCPPDUNumber', + ID=3), + 32 : _GTPUHdrExtCont('ServiceClassInd', GEN=( + Uint8('Value'), + Uint8('spare', rep=REPR_HEX), + ), ID=32), + 64 : _GTPUHdrExtCont('UDPPort', GEN=( + Uint16('Value'), + ), ID=64), + 129 : _GTPUHdrExtCont('RANContainer', + ID=129), + 130 : _LongPDCPPDUNumber('LongPDCPPDUNumber', + ID=130), + 131 : _GTPUHdrExtCont('XwRANContainer', + ID=131), + 132 : _GTPUHdrExtCont('NRRANContainer', + D=132), + 133 : _GTPUHdrExtCont('PDUSessionContainer', + ID=133), + 192 : _GTPUHdrExtCont('PDCPPDUNumber', GEN=( + Uint('Value', bl=15), + Uint('spare', bl=1, rep=REPR_HEX), + ), ID=192) + } + + +class GTPUHdrExt(Envelope): + _GEN = ( Uint8('Len'), - BufAligned('Content', rep=REPR_HEX), + _GTPUHdrExtCont('Content', rep=REPR_HEX), Uint8('NextExt', dic=GTPUNextExtHeader_dict) ) def __init__(self, *args, **kwargs): - GTPUHdrExt.__init__(self, *args, **kwargs) + Envelope.__init__(self, *args, **kwargs) self[0].set_valauto(lambda: (2 + self[1].get_len()) >> 2) - self[1].set_blauto(lambda: max(0, (self[0].get_val()*32) - 16)) - - -#------------------------------------------------------------------------------# -# UDP Port -# TS 29.281, section 5.2.2.1 -#------------------------------------------------------------------------------# - -class GTPUHdrExt64(GTPUHdrExt): - _ID = 64 - _GEN = ( - Uint8('Len', val=1), - Uint16('UDPPort'), - Uint8('NextExt') - ) - - -#------------------------------------------------------------------------------# -# PDCP PDU Number -# TS 29.281, section 5.2.2.2 -#------------------------------------------------------------------------------# - -class GTPUHdrExt192(GTPUHdrExt): - _ID = 192 - _GEN = ( - Uint8('Len', val=1), - Uint('PDCPPDUNumber', bl=15), - Uint('spare', bl=1, rep=REPR_HEX), - Uint8('NextExt') - ) - - -#------------------------------------------------------------------------------# -# Long PDCP PDU Number -# TS 29.281, section 5.2.2.2A -#------------------------------------------------------------------------------# - -class GTPUHdrExt3(GTPUHdrExt): - _ID = 3 - _GEN = ( - Uint8('Len', val=2), - Uint('spare', bl=6, rep=REPR_HEX), - Uint('LongPDCPPDUNumber', bl=18), - Uint24('spare', rep=REPR_HEX), - Uint8('NextExt') - ) - - -#------------------------------------------------------------------------------# -# Service Class Indicator -# TS 29.281, section 5.2.2.3 -#------------------------------------------------------------------------------# - -class GTPUHdrExt32(GTPUHdrExt): - _ID = 32 - _GEN = ( - Uint8('Len', val=1), - Uint8('ServiceClassInd'), - Uint8('spare', rep=REPR_HEX), - Uint8('NextExt') - ) - - -#------------------------------------------------------------------------------# -# RAN Container -# TS 29.281, section 5.2.2.4 -#------------------------------------------------------------------------------# - -class GTPUHdrExt129(GTPUHdrExtAuto): - _ID = 129 - _GEN = ( - Uint8('Len'), - BufAligned('RANContainer', rep=REPR_HEX), - Uint8('NextExt') - ) - - -#------------------------------------------------------------------------------# -# Xw RAN Container -# TS 29.281, section 5.2.2.5 -#------------------------------------------------------------------------------# - -class GTPUHdrExt131(GTPUHdrExtAuto): - _ID = 131 - _GEN = ( - Uint8('Len'), - BufAligned('XwRANContainer', rep=REPR_HEX), - Uint8('NextExt') - ) - - -#------------------------------------------------------------------------------# -# NR RAN Container -# TS 29.281, section 5.2.2.6 -#------------------------------------------------------------------------------# - -class GTPUHdrExt132(GTPUHdrExtAuto): - _ID = 132 - _GEN = ( - Uint8('Len'), - BufAligned('NRRANContainer', rep=REPR_HEX), - Uint8('NextExt') - ) - - -#------------------------------------------------------------------------------# -# PDU Session Container -# TS 29.281, section 5.2.2.7 -#------------------------------------------------------------------------------# - -class GTPUHdrExt133(GTPUHdrExtAuto): - _ID = 133 - _GEN = ( - Uint8('Len'), - BufAligned('PDUSessionContainer', rep=REPR_HEX), - Uint8('NextExt') - ) + self[1].set_blauto(lambda: self._get_cont_len()) + self[2].set_valauto(lambda: self._get_ne()) + + def _get_cont_len(self): + return max(0, (self[0].get_val()*32) - 16) + + def _get_ne(self): + n = self.get_next() + if n: + return n[1]._ID + else: + return 0 + + def set_val(self, val): + self._set_cont_cls() + Envelope.set_val(self, val) + + def _from_char(self, char): + self._set_cont_cls() + Envelope._from_char(self, char) + + def _set_cont_cls(self): + ne = 1 + if self._env: + p = self.get_prev() + if p: + # get NextExt from previous GTPUHdrExt + ne = p['NextExt'].get_val() + elif self._env._env: + # get NextExt from GTPUHdrOpt + ne = self._env._env['GTPUHdrOpt']['NextExt'].get_val() + if ne in GTPUHdrExtCont_dict: + Cont = GTPUHdrExtCont_dict[ne].clone() + Cont.set_blauto(lambda: self._get_cont_len()) + self.replace(self[1], Cont) #------------------------------------------------------------------------------# @@ -258,35 +202,24 @@ class GTPUHdrExt133(GTPUHdrExtAuto): # TS 29.281, section 5.1 #------------------------------------------------------------------------------# -# Warning: this GTPUHdrExtList is not friendly to build, as the user requires to -# explicitely add GTPUHdrExt.. into it when building a message - -class GTPUHdrExtList(Envelope): - _GEN = () - _HdrExt = { - 3 : GTPUHdrExt3, - 32 : GTPUHdrExt32, - 64 : GTPUHdrExt64, - 129 : GTPUHdrExt129, - 130 : GTPUHdrExt3, - 131 : GTPUHdrExt131, - 132 : GTPUHdrExt132, - 133 : GTPUHdrExt133, - 192 : GTPUHdrExt192 - } +class GTPUHdrExtList(Sequence): + _GEN = GTPUHdrExt() def _from_char(self, char): if self.get_trans(): return - self.__init__() + self.set_val(None) + l = 0 p = self.get_prev() - if p and not p.get_trans(): - neid = p['NextExt'].get_val() - while neid > 0 and char.len_bit() >= 32: - ne = self._HdrExt.get(neid, GTPUHdrExtAuto)() - ne._from_char(char) - self.append(ne) - neid = ne['NextExt'].get_val() + if not p: + return + l += 1 + self.set_num(l) + self[-1]._from_char(char) + while self[-1]['NextExt'].get_val() != 0: + l += 1 + self.set_num(l) + self[-1]._from_char(char) class GTPUHdrOpt(Envelope): @@ -298,19 +231,19 @@ class GTPUHdrOpt(Envelope): def __init__(self, *args, **kwargs): Envelope.__init__(self, *args, **kwargs) - self[-1].set_valauto(lambda: self._get_next_hdr()) + self[-1].set_valauto(lambda: self._get_ne()) - def _get_next_hdr(self): + def _get_ne(self): n = self.get_next() - if isinstance(n, GTPUHdrExtList) and len(n._content) and hasattr(n[0], '_ID'): - return n[0]._ID + if isinstance(n, GTPUHdrExtList) and n.get_num(): + return n[0][1]._ID else: return 0 ProtType_dict = { 0 : 'GTP prime', - 1 : 'GTP', + 1 : 'GTP', # the one for GTP-U } GTPUType_dict = { @@ -324,13 +257,13 @@ GTPUType_dict = { } class GTPUType(IntEnum): - EchoRequest = 1 - EchoResponse = 2 - ErrorIndication = 26 - SupportedExtensionHeadersNotification = 31 - TunnelStatus = 253 - EndMarker = 254 - GPDU = 255 + EchoRequest = 1 + EchoResponse = 2 + ErrorIndication = 26 + SupportedExtensionHeadersNotification = 31 + TunnelStatus = 253 + EndMarker = 254 + GPDU = 255 class GTPUHdr(Envelope): @@ -464,7 +397,7 @@ class GTPUIEPrivateExt(GTPUIE): # TS 29.281, section 7 #------------------------------------------------------------------------------# -class GTPUMsg(Envelope): +class _GTPUMsg(Envelope): ENV_SEL_TRANS = False @@ -499,9 +432,9 @@ class GTPUMsg(Envelope): # TS 29.281, section 7.2.1 #------------------------------------------------------------------------------# -class GTPUEchoRequest(GTPUMsg): +class GTPUEchoRequest(_GTPUMsg): _GEN = ( - GTPUHdr(val={'Type': 1}), + GTPUHdr(val={'Type': GTPUType.EchoRequest.value}), GTPUIEPrivateExt(hier=1, trans=True) # optional ) @@ -511,9 +444,9 @@ class GTPUEchoRequest(GTPUMsg): # TS 29.281, section 7.2.2 #------------------------------------------------------------------------------# -class GTPUEchoResponse(GTPUMsg): +class GTPUEchoResponse(_GTPUMsg): _GEN = ( - GTPUHdr(val={'Type': 2}), + GTPUHdr(val={'Type': GTPUType.EchoResponse.value}), GTPUIERecovery(hier=1), GTPUIEPrivateExt(hier=1, trans=True) # optional ) @@ -524,9 +457,9 @@ class GTPUEchoResponse(GTPUMsg): # TS 29.281, section 7.2.3 #------------------------------------------------------------------------------# -class GTPUSuppExtHdrNotif(GTPUMsg): +class GTPUSuppExtHdrNotif(_GTPUMsg): _GEN = ( - GTPUHdr(val={'Type': 31}), + GTPUHdr(val={'Type': GTPUType.SupportedExtensionHeadersNotification.value}), GTPUIEExtHdrList(hier=1) ) @@ -536,9 +469,9 @@ class GTPUSuppExtHdrNotif(GTPUMsg): # TS 29.281, section 7.3.1 #------------------------------------------------------------------------------# -class GTPUErrorInd(GTPUMsg): +class GTPUErrorInd(_GTPUMsg): _GEN = ( - GTPUHdr(val={'Type': 26}), + GTPUHdr(val={'Type': GTPUType.ErrorIndication.value}), GTPUIETEID(hier=1), GTPUIEPeerAddr(hier=1), GTPUIEPrivateExt(hier=1, trans=True) # optional @@ -550,9 +483,9 @@ class GTPUErrorInd(GTPUMsg): # TS 29.281, section 7.3.2 #------------------------------------------------------------------------------# -class GTPUEndMarker(GTPUMsg): +class GTPUEndMarker(_GTPUMsg): _GEN = ( - GTPUHdr(val={'Type': 254}), + GTPUHdr(val={'Type': GTPUType.EndMarker.value}), GTPUIEPrivateExt(hier=1, trans=True) # optional ) @@ -562,9 +495,9 @@ class GTPUEndMarker(GTPUMsg): # TS 29.281, section 7.3.3 #------------------------------------------------------------------------------# -class GTPUTunnelStatus(GTPUMsg): +class GTPUTunnelStatus(_GTPUMsg): _GEN = ( - GTPUHdr(val={'Type': 253}), + GTPUHdr(val={'Type': GTPUType.TunnelStatus.value}), GTPUIEPrivateExt(hier=1, trans=True) # optional ) @@ -576,7 +509,7 @@ class GTPUTunnelStatus(GTPUMsg): class GPDU(Envelope): _GEN = ( - GTPUHdr(val={'Type': 255}), + GTPUHdr(val={'Type': GTPUType.GPDU.value}), Buf('TPDU', hier=1, rep=REPR_HEX) ) @@ -586,9 +519,10 @@ GTPUDispatcher = { 2 : GTPUEchoResponse, 26 : GTPUErrorInd, 31 : GTPUSuppExtHdrNotif, + 253 : GTPUTunnelStatus, 254 : GTPUEndMarker, - 255 : GPDU -} + 255 : GPDU, + } ERR_GTPU_BUF_TOO_SHORT = 1