[ViewVC] Diff of: cvs/Convert-BER-XS/XS.pm

Comparing Convert-BER-XS/XS.pm (file contents):
Revision 1.6 by root, Fri Apr 19 20:38:38 2019 UTC vs.
Revision 1.18 by root, Sat Apr 20 13:48:53 2019 UTC

…		…
7	use Convert::BER::XS ':all';	7	use Convert::BER::XS ':all';
8		8
9	my $ber = ber_decode $buf	9	my $ber = ber_decode $buf
10	or die "unable to decode SNMP message";	10	or die "unable to decode SNMP message";
11		11
12	# The above results in a data structure consisting of (class, tag,	12	# The above results in a data structure consisting of
		13	# (class, tag, # constructed, data)
13	# constructed, data) tuples. Below is such a message, SNMPv1 trap	14	# tuples. Below is such a message, SNMPv1 trap
14	# with a Cisco mac change notification.	15	# with a Cisco mac change notification.
15	# Did you know that Cisco is in the news almost every week because	16	# Did you know that Cisco is in the news almost
		17	# every week because # of some backdoor password
16	# of some backdoor password or other extremely stupid security bug?	18	# or other extremely stupid security bug?
17		19
18	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1,	20	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1,
19	[	21	[
20	[ ASN_UNIVERSAL, ASN_INTEGER32, 0, 0 ], # snmp version 1	22	[ ASN_UNIVERSAL, ASN_INTEGER32, 0, 0 ], # snmp version 1
21	[ ASN_UNIVERSAL, 4, 0, "public" ], # community	23	[ ASN_UNIVERSAL, 4, 0, "public" ], # community
…		…
28	[ ASN_APPLICATION, ASN_TIMETICKS, 0, 1817903850 ], # SNMP TimeTicks	30	[ ASN_APPLICATION, ASN_TIMETICKS, 0, 1817903850 ], # SNMP TimeTicks
29	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # the varbindlist	31	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # the varbindlist
30	[	32	[
31	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # a single varbind, "key value" pair	33	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # a single varbind, "key value" pair
32	[	34	[
33	[ ASN_UNIVERSAL, ASN_OBJECT_IDENTIFIER, 0, "1.3.6.1.4.1.9.9.215.1.1.8.1.2.1" ], # the oid	35	[ ASN_UNIVERSAL, ASN_OBJECT_IDENTIFIER, 0, "1.3.6.1.4.1.9.9.215.1.1.8.1.2.1" ],
34	[ ASN_UNIVERSAL, ASN_OCTET_STRING, 0, "...data..." # the value	36	[ ASN_UNIVERSAL, ASN_OCTET_STRING, 0, "...data..." # the value
35	]	37	]
36	]	38	]
37	],	39	],
38	...	40	...
…		…
64		66
65	my $buf = ber_encode $ber;	67	my $buf = ber_encode $ber;
66		68
67	=head1 DESCRIPTION	69	=head1 DESCRIPTION
68		70
		71	WARNING: Before release 1.0, the API is not considered stable in any way.
		72
69	This module implements a I<very> low level BER/DER en-/decoder.	73	This module implements a I<very> low level BER/DER en-/decoder.
70		74
71	If is tuned for low memory and high speed, while still maintaining some	75	If is tuned for low memory and high speed, while still maintaining some
72	level of user-friendlyness.	76	level of user-friendlyness.
73		77
74	Currently, not much is documented, as this is an initial release to
75	reserve CPAN namespace, stay tuned for a few days.
76
77	=head2 ASN.1/BER/DER/... BASICS	78	=head2 ASN.1/BER/DER/... BASICS
78		79
79	ASN.1 is a strange language that can be sed to describe protocols and	80	ASN.1 is a strange language that can be used to describe protocols and
80	data structures. It supports various mappings to JSON, XML, but most	81	data structures. It supports various mappings to JSON, XML, but most
81	importantly, to a various binary encodings such as BER, that is the topic	82	importantly, to a various binary encodings such as BER, that is the topic
82	of this module, and is used in SNMP or LDAP for example.	83	of this module, and is used in SNMP or LDAP for example.
83		84
84	While ASN.1 defines a schema that is useful to interpret encoded data,	85	While ASN.1 defines a schema that is useful to interpret encoded data,
85	the BER encoding is actually somehat self-describing: you might not know	86	the BER encoding is actually somewhat self-describing: you might not know
86	whether something is a string or a number or a sequence or something else,	87	whether something is a string or a number or a sequence or something else,
87	but you can nevertheless decode the overall structure, even if you end up	88	but you can nevertheless decode the overall structure, even if you end up
88	with just a binary blob for the actual value.	89	with just a binary blob for the actual value.
89		90
90	This works because BER values are tagged with a type and a namespace,	91	This works because BER values are tagged with a type and a namespace,
91	and also have a flag that says whther a value consists of subvalues (is	92	and also have a flag that says whether a value consists of subvalues (is
92	"constructed") or not (is "primitive").	93	"constructed") or not (is "primitive").
93		94
94	Tags are simple integers, and ASN.1 defines a somewhat weird assortment of	95	Tags are simple integers, and ASN.1 defines a somewhat weird assortment of
95	those - for example, you have 32 bit signed integers and 16(!) different	96	those - for example, you have 32 bit signed integers and 16(!) different
96	string types, but there is no unsigned32 type for example. Different	97	string types, but there is no unsigned32 type for example. Different
…		…
118	I<DATA> member, and you may re-assign the array itself, e.g.:	119	I<DATA> member, and you may re-assign the array itself, e.g.:
119		120
120	$ber = ber_decode $binbuf;	121	$ber = ber_decode $binbuf;
121		122
122	# the following is NOT legal:	123	# the following is NOT legal:
123	$ber->[BER_CLASS] = ASN_PRIVATE; # ERROR, readonly(!)	124	$ber->[BER_CLASS] = ASN_PRIVATE; # ERROR, CLASS/TAG/CONSTRUCTED are READ ONLY(!)
124		125
125	# but all of the following are fine:	126	# but all of the following are fine:
126	$ber->[BER_DATA] = "string";	127	$ber->[BER_DATA] = "string";
127	$ber->[BER_DATA] = [ASN_UNIVERSAL, ASN_INTEGER32, 0, 123];	128	$ber->[BER_DATA] = [ASN_UNIVERSAL, ASN_INTEGER32, 0, 123];
128	@$ber = (ASN_APPLICATION, SNMP_TIMETICKS, 1000);	129	@$ber = (ASN_APPLICATION, SNMP_TIMETICKS, 0, 1000);
129		130
130	I<CLASS> is something like a namespace for I<TAG>s - there is the	131	I<CLASS> is something like a namespace for I<TAG>s - there is the
131	C<ASN_UNIVERSAL> namespace which defines tags common to all ASN.1	132	C<ASN_UNIVERSAL> namespace which defines tags common to all ASN.1
132	implementations, the C<ASN_APPLICATION> namespace which defines tags for	133	implementations, the C<ASN_APPLICATION> namespace which defines tags for
133	specific applications (for example, the SNMP C<Unsigned32> type is in this	134	specific applications (for example, the SNMP C<Unsigned32> type is in this
…		…
164	Thus, you can always decode a BER data structure and at worst you get a	165	Thus, you can always decode a BER data structure and at worst you get a
165	string in place of some nice decoded value.	166	string in place of some nice decoded value.
166		167
167	See the SYNOPSIS for an example of such an encoded tuple representation.	168	See the SYNOPSIS for an example of such an encoded tuple representation.
168		169
		170	=head2 DECODING AND ENCODING
		171
		172	=over
		173
		174	=item $tuple = ber_decoded $bindata
		175
		176	Decodes binary BER data in C<$bindata> and returns the resulting BER
		177	tuple. Croaks on any decoding error, so the returned C<$tuple> is always
		178	valid.
		179
		180	=item $bindata = ber_encode $tuple
		181
		182	Encodes the BER tuple into a BER/DER data structure.
		183
		184	=back
		185
169	=head2 HELPER FUNCTIONS	186	=head2 HELPER FUNCTIONS
170		187
171	Working with a 4-tuple for every value can be annoying. Or, rather, I<is>	188	Working with a 4-tuple for every value can be annoying. Or, rather, I<is>
172	annoying. To reduce this a bit, this module defines a number of helper	189	annoying. To reduce this a bit, this module defines a number of helper
173	functions, both to match BER tuples and to conmstruct BER tuples:	190	functions, both to match BER tuples and to conmstruct BER tuples:
…		…
231	true.	248	true.
232		249
233	=item $bool = ber_is_oid $tuple, $oid_string	250	=item $bool = ber_is_oid $tuple, $oid_string
234		251
235	Returns true if the C<$tuple> represents an ASN_OBJECT_IDENTIFIER	252	Returns true if the C<$tuple> represents an ASN_OBJECT_IDENTIFIER
236	that exactly matches C$oid_string>. Exmaple:	253	that exactly matches C<$oid_string>. Example:
237		254
238	ber_is_oid $tuple, "1.3.6.1.4"	255	ber_is_oid $tuple, "1.3.6.1.4"
239	or die "oid must be 1.3.6.1.4";	256	or die "oid must be 1.3.6.1.4";
240		257
241	=item $oid = ber_is_oid $tuple	258	=item $oid = ber_is_oid $tuple
…		…
269	use common::sense;	286	use common::sense;
270		287
271	use XSLoader ();	288	use XSLoader ();
272	use Exporter qw(import);	289	use Exporter qw(import);
273		290
274	our $VERSION = 0.1;	291	our $VERSION;
275		292
		293	BEGIN {
		294	$VERSION = 0.8;
276	XSLoader::load __PACKAGE__, $VERSION;	295	XSLoader::load __PACKAGE__, $VERSION;
		296	}
277		297
278	our %EXPORT_TAGS = (	298	our %EXPORT_TAGS = (
279	const => [qw(	299	const => [qw(
280	BER_CLASS BER_TAG BER_CONSTRUCTED BER_DATA	300	BER_CLASS BER_TAG BER_CONSTRUCTED BER_DATA
281		301
282	ASN_BOOLEAN ASN_INTEGER32 ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER ASN_TAG_BER ASN_TAG_MASK	302	ASN_BOOLEAN ASN_INTEGER32 ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER
283	ASN_CONSTRUCTED ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE ASN_CLASS_MASK ASN_CLASS_SHIFT	303	ASN_OBJECT_DESCRIPTOR ASN_OID ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED
284	ASN_SEQUENCE	304	ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING
285		305	ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING
		306	ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING
		307	ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING
		308
		309	ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE
		310
		311	BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT
		312	BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL
		313	BER_TYPE_IPADDRESS BER_TYPE_CROAK
		314	)],
		315	const_snmp => [qw(
286	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64	316	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
287	)],	317	)],
288	encode => [qw(	318	encode => [qw(
289	ber_decode	319	ber_decode
290	ber_is ber_is_seq ber_is_i32 ber_is_oid	320	ber_is ber_is_seq ber_is_i32 ber_is_oid
291	)],	321	)],
292	decode => [qw(	322	decode => [qw(
293	ber_encode	323	ber_encode
		324	ber_i32
294	)],	325	)],
295	);	326	);
296		327
297	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;	328	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;
298		329
299	$EXPORT_TAGS{all} = \@EXPORT_OK;	330	$EXPORT_TAGS{all} = \@EXPORT_OK;
300		331
		332	=head1 PROFILES
		333
		334	While any BER data can be correctly encoded and decoded out of the box, it
		335	can be inconvenient to have to manually decode some values into a "better"
		336	format: for instance, SNMP TimeTicks values are decoded into the raw octet
		337	strings of their BER representation, which is quite hard to decode. With
		338	profiles, you can change which class/tag combinations map to which decoder
		339	function inside C<ber_decode> (and of course also which encoder functions
		340	are used in C<ber_encode>).
		341
		342	This works by mapping specific class/tag combinations to an internal "ber
		343	type".
		344
		345	The default profile supports the standard ASN.1 types, but no
		346	application-specific ones. This means that class/tag combinations not in
		347	the base set of ASN.1 are decoded into their raw octet strings.
		348
		349	C<Convert::BER::XS> defines two profile variables you can use out of the box:
		350
		351	=over
		352
		353	=item C<$Convert::BER::XS::DEFAULT_PROFILE>
		354
		355	This is the default profile, i.e. the profile that is used when no
		356	profile is specified for de-/encoding.
		357
		358	You can modify it, but remember that this modifies the defaults for all
		359	callers that rely on the default profile.
		360
		361	=item C<$Convert::BER::XS::SNMP_PROFILE>
		362
		363	A profile with mappings for SNMP-specific application tags added. This is
		364	useful when de-/encoding SNMP data.
		365
		366	Example:
		367
		368	$ber = ber_decode $data, $Convert::BER::XS::SNMP_PROFILE;
		369
		370	=back
		371
		372	=head2 The Convert::BER::XS::Profile class
		373
		374	=over
		375
		376	=item $profile = new Convert::BER::XS::Profile
		377
		378	Create a new profile. The profile will be identical to the default
		379	profile.
		380
		381	=item $profile->set ($class, $tag, $type)
		382
		383	Sets the mapping for the given C<$class>/C<$tag> combination to C<$type>,
		384	which must be one of the C<BER_TYPE_*> constants.
		385
		386	Note that currently, the mapping is stored in a flat array, so large
		387	values of C<$tag> will consume large amounts of memory.
		388
		389	Example:
		390
		391	$profile = new Convert::BER::XS::Profile;
		392	$profile->set (ASN_APPLICATION, SNMP_COUNTER32, BER_TYPE_INT);
		393	$ber = ber_decode $data, $profile;
		394
		395	=item $type = $profile->get ($class, $tag)
		396
		397	Returns the BER type mapped to the given C<$class>/C<$tag> combination.
		398
		399	=back
		400
		401	=head2 BER TYPES
		402
		403	This lists the predefined BER types - you can map any C<CLASS>/C<TAG>
		404	combination to any C<BER_TYPE_*>.
		405
		406	=over
		407
		408	=item C<BER_TYPE_BYTES>
		409
		410	The raw octets of the value. This is the default type for unknown tags and
		411	de-/encodes the value as if it were an octet string, i.e. by copying the
		412	raw bytes.
		413
		414	=item C<BER_TYPE_UTF8>
		415
		416	Like C<BER_TYPE_BYTES>, but decodes the value as if it were a UTF-8 string
		417	(without validation!) and encodes a perl unicode string into a UTF-8 BER
		418	string.
		419
		420	=item C<BER_TYPE_UCS2>
		421
		422	Similar to C<BER_TYPE_UTF8>, but treats the BER value as UCS-2 encoded
		423	string.
		424
		425	=item C<BER_TYPE_UCS4>
		426
		427	Similar to C<BER_TYPE_UTF8>, but treats the BER value as UCS-4 encoded
		428	string.
		429
		430	=item C<BER_TYPE_INT>
		431
		432	Encodes and decodes a BER integer value to a perl integer scalar. This
		433	should correctly handle 64 bit signed and unsigned values.
		434
		435	=item C<BER_TYPE_OID>
		436
		437	Encodes and decodes an OBJECT IDENTIFIER into dotted form without leading
		438	dot, e.g. C<1.3.6.1.213>.
		439
		440	=item C<BER_TYPE_RELOID>
		441
		442	Same as C<BER_TYPE_OID> but uses relative object identifier
		443	encoding: ASN.1 has this hack of encoding the first two OID components
		444	into a single integer in a weird attempt to save an insignificant amount
		445	of space in an otherwise wasteful encoding, and relative OIDs are
		446	basically OIDs without this hack. The practical difference is that the
		447	second component of an OID can only have the values 1..40, while relative
		448	OIDs do not have this restriction.
		449
		450	=item C<BER_TYPE_NULL>
		451
		452	Decodes an C<ASN_NULL> value into C<undef>, and always encodes a
		453	C<ASN_NULL> type, regardless of the perl value.
		454
		455	=item C<BER_TYPE_BOOL>
		456
		457	Decodes an C<ASN_BOOLEAN> value into C<0> or C<1>, and encodes a perl
		458	boolean value into an C<ASN_BOOLEAN>.
		459
		460	=item C<BER_TYPE_REAL>
		461
		462	Decodes/encodes a BER real value. NOT IMPLEMENTED.
		463
		464	=item C<BER_TYPE_IPADDRESS>
		465
		466	Decodes/encodes a four byte string into an IPv4 dotted-quad address string
		467	in Perl. Given the obsolete nature of this type, this is a low-effort
		468	implementation that simply uses C<sprintf> and C<sscanf>-style conversion,
		469	so it won't handle all string forms supported by C<inet_aton> for example.
		470
		471	=item C<BER_TYPE_CROAK>
		472
		473	Always croaks when encountered during encoding or decoding - the
		474	default behaviour when encountering an unknown type is to treat it as
		475	C<BER_TYPE_BYTES>. When you don't want that but instead prefer a hard
		476	error for some types, then C<BER_TYPE_CROAK> is for you.
		477
		478	=back
		479
		480	=cut
		481
		482	our $DEFAULT_PROFILE = new Convert::BER::XS::Profile;
		483	our $SNMP_PROFILE = new Convert::BER::XS::Profile;
		484
		485	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS);
		486	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT);
		487	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT);
		488	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT);
		489	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_IPADDRESS);
		490	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT);
		491
		492	$DEFAULT_PROFILE->_set_default;
		493
301	1;	494	1;
302		495
303	=head2 BUGS / SHORTCOMINGs	496	=head2 LIMITATIONS
304		497
305	This module does have a number of SNMPisms hardcoded, such as the SNMP	498	This module can only en-/decode 64 bit signed and unsigned integers, and
306	tags for Unsigned32 and so on. More configurability is needed, and, if	499	only when your perl supports those.
307	ever implemented, will come in a form similar to how L<JSON::XS> and	500
308	L<CBOR::XS> respresent things, namely with an object-oriented interface.	501	OBJECT IDENTIFIEERs cannot have unlimited length, although the limit is
		502	much larger than e.g. the one imposed by SNMP or other protocols.
		503
		504	REAL values are not supported and will croak.
		505
		506	This module has undergone little to no testing so far.
		507
		508	=head2 ITHREADS SUPPORT
		509
		510	This module is unlikely to work when the (officially discouraged) ithreads
		511	are in use.
309		512
310	=head1 AUTHOR	513	=head1 AUTHOR
311		514
312	Marc Lehmann <schmorp@schmorp.de>	515	Marc Lehmann <schmorp@schmorp.de>
313	http://software.schmorp.de/pkg/Convert-BER-XS	516	http://software.schmorp.de/pkg/Convert-BER-XS

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Comparing Convert-BER-XS/XS.pm (file contents): Revision 1.6 by root, Fri Apr 19 20:38:38 2019 UTC vs. Revision 1.18 by root, Sat Apr 20 13:48:53 2019 UTC

Diff Legend

Comparing Convert-BER-XS/XS.pm (file contents):
Revision 1.6 by root, Fri Apr 19 20:38:38 2019 UTC vs.
Revision 1.18 by root, Sat Apr 20 13:48:53 2019 UTC