Add codecs for EF_SPN and GSM strings via construct
This will replace the hand-crafted codec for EF_SPN
by a struct definition using the construct library.
Old encoders are updated and kept for API compatibility
but are not used internally anymore.
New data structures:
* Rpad(Adapter): Right-padded bytestring (0xff, adjustable)
* GsmStringAdapter(Adapter): Codec for "SMS default 7-bit
coded alphabet as defined int TS 23.038" using
the gsm0338 library.
* GsmString(n): Convenient wrapper of both above
Adjustments:
* utils: update+deprecate old dec_spn(), enc_spn()
* remove refs to deprecated functions
Change-Id: Ia1d3a3835933bac0002b7c52511481dd8094b994
diff --git a/contrib/jenkins.sh b/contrib/jenkins.sh
index ed5ba25..27f0245 100755
--- a/contrib/jenkins.sh
+++ b/contrib/jenkins.sh
@@ -23,6 +23,7 @@
pip install jsonpath-ng
pip install construct
pip install bidict
+pip install gsm0338
# Execute automatically discovered unit tests first
python -m unittest discover -v -s tests/
diff --git a/pySim-read.py b/pySim-read.py
index ebe0e29..9feef9d 100755
--- a/pySim-read.py
+++ b/pySim-read.py
@@ -36,7 +36,7 @@
from pySim.transport import init_reader, argparse_add_reader_args
from pySim.cards import card_detect, Card, UsimCard, IsimCard
from pySim.utils import h2b, swap_nibbles, rpad, dec_imsi, dec_iccid, dec_msisdn
-from pySim.utils import format_xplmn_w_act, dec_spn, dec_st, dec_addr_tlv
+from pySim.utils import format_xplmn_w_act, dec_st, dec_addr_tlv
from pySim.utils import h2s, format_ePDGSelection
option_parser = argparse.ArgumentParser(prog='pySim-read',
diff --git a/pySim/cards.py b/pySim/cards.py
index 30857b3..dcba26c 100644
--- a/pySim/cards.py
+++ b/pySim/cards.py
@@ -25,7 +25,7 @@
from typing import Optional, Dict, Tuple
import abc
-from pySim.ts_51_011 import EF, DF, EF_AD
+from pySim.ts_51_011 import EF, DF, EF_AD, EF_SPN
from pySim.ts_31_102 import EF_USIM_ADF_map
from pySim.ts_31_103 import EF_ISIM_ADF_map
from pySim.utils import *
@@ -203,15 +203,24 @@
return sw
def read_spn(self):
- (spn, sw) = self._scc.read_binary(EF['SPN'])
+ (content, sw) = self._scc.read_binary(EF['SPN'])
if sw == '9000':
- return (dec_spn(spn), sw)
+ abstract_data = EF_SPN().decode_hex(content)
+ show_in_hplmn = abstract_data['show_in_hplmn']
+ hide_in_oplmn = abstract_data['hide_in_oplmn']
+ name = abstract_data['spn']
+ return ((name, show_in_hplmn, hide_in_oplmn), sw)
else:
return (None, sw)
- def update_spn(self, name, hplmn_disp=False, oplmn_disp=False):
- content = enc_spn(name, hplmn_disp, oplmn_disp)
- data, sw = self._scc.update_binary(EF['SPN'], rpad(content, 32))
+ def update_spn(self, name="", show_in_hplmn=False, hide_in_oplmn=False):
+ abstract_data = {
+ 'hide_in_oplmn' : hide_in_oplmn,
+ 'show_in_hplmn' : show_in_hplmn,
+ 'spn' : name,
+ }
+ content = EF_SPN().encode_hex(abstract_data)
+ data, sw = self._scc.update_binary(EF['SPN'], content)
return sw
def read_binary(self, ef, length=None, offset=0):
@@ -915,8 +924,7 @@
# set Service Provider Name
if p.get('name') is not None:
- content = enc_spn(p['name'], True, True)
- data, sw = self._scc.update_binary('6F46', rpad(content, 32))
+ self.update_spn(p['name'], True, True)
if p.get('acc') is not None:
self.update_acc(p['acc'])
@@ -1310,8 +1318,7 @@
# set Service Provider Name
if p.get('name') is not None:
- content = enc_spn(p['name'], True, True)
- data, sw = self._scc.update_binary('6F46', rpad(content, 32))
+ self.update_spn(p['name'], True, True)
# write EF.IMSI
if p.get('imsi'):
diff --git a/pySim/construct.py b/pySim/construct.py
index b0f03b7..a903305 100644
--- a/pySim/construct.py
+++ b/pySim/construct.py
@@ -1,5 +1,6 @@
from construct import *
from pySim.utils import b2h, h2b, swap_nibbles
+import gsm0338
"""Utility code related to the integration of the 'construct' declarative parser."""
@@ -33,6 +34,42 @@
def _encode(self, obj, context, path):
return h2b(swap_nibbles(obj))
+class Rpad(Adapter):
+ """
+ Encoder appends padding bytes (b'\\xff') up to target size.
+ Decoder removes trailing padding bytes.
+
+ Parameters:
+ subcon: Subconstruct as defined by construct library
+ pattern: set padding pattern (default: b'\\xff')
+ """
+
+ def __init__(self, subcon, pattern=b'\xff'):
+ super().__init__(subcon)
+ self.pattern = pattern
+
+ def _decode(self, obj, context, path):
+ return obj.rstrip(self.pattern)
+
+ def _encode(self, obj, context, path):
+ if len(obj) > self.sizeof():
+ raise SizeofError("Input ({}) exceeds target size ({})".format(len(obj), self.sizeof()))
+ return obj + self.pattern * (self.sizeof() - len(obj))
+
+class GsmStringAdapter(Adapter):
+ """Convert GSM 03.38 encoded bytes to a string."""
+
+ def __init__(self, subcon, codec='gsm03.38', err='strict'):
+ super().__init__(subcon)
+ self.codec = codec
+ self.err = err
+
+ def _decode(self, obj, context, path):
+ return obj.decode(self.codec)
+
+ def _encode(self, obj, context, path):
+ return obj.encode(self.codec, self.err)
+
def filter_dict(d, exclude_prefix='_'):
"""filter the input dict to ensure no keys starting with 'exclude_prefix' remain."""
res = {}
@@ -88,3 +125,17 @@
n (Integer): Number of bytes (default: 1)
'''
return Default(Bytes(n), __RFU_VALUE)
+
+def GsmString(n):
+ '''
+ GSM 03.38 encoded byte string of fixed length n.
+ Encoder appends padding bytes (b'\\xff') to maintain
+ length. Decoder removes those trailing bytes.
+
+ Exceptions are raised for invalid characters
+ and length excess.
+
+ Parameters:
+ n (Integer): Fixed length of the encoded byte string
+ '''
+ return GsmStringAdapter(Rpad(Bytes(n), pattern=b'\xff'), codec='gsm03.38')
diff --git a/pySim/ts_51_011.py b/pySim/ts_51_011.py
index dba0369..6ab07f0 100644
--- a/pySim/ts_51_011.py
+++ b/pySim/ts_51_011.py
@@ -323,7 +323,7 @@
from struct import pack, unpack
from construct import *
from construct import Optional as COptional
-from pySim.construct import HexAdapter, BcdAdapter, FlagRFU, ByteRFU, GreedyBytesRFU, BitsRFU, BytesRFU
+from pySim.construct import *
import enum
from pySim.filesystem import *
@@ -519,11 +519,14 @@
class EF_SPN(TransparentEF):
def __init__(self, fid='6f46', sfid=None, name='EF.SPN', desc='Service Provider Name', size={17,17}):
super().__init__(fid, sfid=sfid, name=name, desc=desc, size=size)
- def _decode_hex(self, raw_hex):
- return {'spn': dec_spn(raw_hex)}
- def _encode_hex(self, abstract):
- spn = abstract['spn']
- return enc_spn(spn[0], spn[1], spn[2])
+ self._construct = BitStruct(
+ # Byte 1
+ 'rfu'/BitsRFU(6),
+ 'hide_in_oplmn'/Flag,
+ 'show_in_hplmn'/Flag,
+ # Bytes 2..17
+ 'spn'/Bytewise(GsmString(16))
+ )
# TS 51.011 Section 10.3.13
class EF_CBMI(TransRecEF):
diff --git a/pySim/utils.py b/pySim/utils.py
index a3cd1b5..3a8ddac 100644
--- a/pySim/utils.py
+++ b/pySim/utils.py
@@ -248,17 +248,23 @@
return res
def dec_spn(ef):
- byte1 = int(ef[0:2])
- hplmn_disp = (byte1&0x01 == 0x01)
- oplmn_disp = (byte1&0x02 == 0x02)
- name = h2s(ef[2:])
- return (name, hplmn_disp, oplmn_disp)
+ """Obsolete, kept for API compatibility"""
+ from ts_51_011 import EF_SPN
+ abstract_data = EF_SPN().decode_hex(ef)
+ show_in_hplmn = abstract_data['show_in_hplmn']
+ hide_in_oplmn = abstract_data['hide_in_oplmn']
+ name = abstract_data['spn']
+ return (name, show_in_hplmn, hide_in_oplmn)
-def enc_spn(name:str, hplmn_disp=False, oplmn_disp=False):
- byte1 = 0x00
- if hplmn_disp: byte1 = byte1|0x01
- if oplmn_disp: byte1 = byte1|0x02
- return i2h([byte1])+s2h(name)
+def enc_spn(name:str, show_in_hplmn=False, hide_in_oplmn=False):
+ """Obsolete, kept for API compatibility"""
+ from ts_51_011 import EF_SPN
+ abstract_data = {
+ 'hide_in_oplmn' : hide_in_oplmn,
+ 'show_in_hplmn' : show_in_hplmn,
+ 'spn' : name,
+ }
+ return EF_SPN().encode_hex(abstract_data)
def hexstr_to_Nbytearr(s, nbytes):
return [s[i:i+(nbytes*2)] for i in range(0, len(s), (nbytes*2)) ]
diff --git a/requirements.txt b/requirements.txt
index 6e8336c..10e9667 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,3 +5,4 @@
jsonpath-ng
construct
bidict
+gsm0338
diff --git a/setup.py b/setup.py
index 08608dc..2ef498f 100644
--- a/setup.py
+++ b/setup.py
@@ -16,6 +16,7 @@
"jsonpath-ng",
"construct >= 2.9",
"bidict",
+ "gsm0338",
],
scripts=[
'pySim-prog.py',