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

Comparing Convert-BER-XS/XS.pm (file contents):
Revision 1.8 by root, Fri Apr 19 20:42:31 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
…		…
71	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.
72		74
73	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
74	level of user-friendlyness.	76	level of user-friendlyness.
75		77
76	Currently, not much is documented, as this is an initial release to
77	reserve CPAN namespace, stay tuned for a few days.
78
79	=head2 ASN.1/BER/DER/... BASICS	78	=head2 ASN.1/BER/DER/... BASICS
80		79
81	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
82	data structures. It supports various mappings to JSON, XML, but most	81	data structures. It supports various mappings to JSON, XML, but most
83	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
84	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.
85		84
86	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,
87	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
88	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,
89	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
90	with just a binary blob for the actual value.	89	with just a binary blob for the actual value.
91		90
92	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,
93	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
94	"constructed") or not (is "primitive").	93	"constructed") or not (is "primitive").
95		94
96	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
97	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
98	string types, but there is no unsigned32 type for example. Different	97	string types, but there is no unsigned32 type for example. Different
…		…
120	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.:
121		120
122	$ber = ber_decode $binbuf;	121	$ber = ber_decode $binbuf;
123		122
124	# the following is NOT legal:	123	# the following is NOT legal:
125	$ber->[BER_CLASS] = ASN_PRIVATE; # ERROR, readonly(!)	124	$ber->[BER_CLASS] = ASN_PRIVATE; # ERROR, CLASS/TAG/CONSTRUCTED are READ ONLY(!)
126		125
127	# but all of the following are fine:	126	# but all of the following are fine:
128	$ber->[BER_DATA] = "string";	127	$ber->[BER_DATA] = "string";
129	$ber->[BER_DATA] = [ASN_UNIVERSAL, ASN_INTEGER32, 0, 123];	128	$ber->[BER_DATA] = [ASN_UNIVERSAL, ASN_INTEGER32, 0, 123];
130	@$ber = (ASN_APPLICATION, SNMP_TIMETICKS, 1000);	129	@$ber = (ASN_APPLICATION, SNMP_TIMETICKS, 0, 1000);
131		130
132	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
133	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
134	implementations, the C<ASN_APPLICATION> namespace which defines tags for	133	implementations, the C<ASN_APPLICATION> namespace which defines tags for
135	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
…		…
249	true.	248	true.
250		249
251	=item $bool = ber_is_oid $tuple, $oid_string	250	=item $bool = ber_is_oid $tuple, $oid_string
252		251
253	Returns true if the C<$tuple> represents an ASN_OBJECT_IDENTIFIER	252	Returns true if the C<$tuple> represents an ASN_OBJECT_IDENTIFIER
254	that exactly matches C$oid_string>. Exmaple:	253	that exactly matches C<$oid_string>. Example:
255		254
256	ber_is_oid $tuple, "1.3.6.1.4"	255	ber_is_oid $tuple, "1.3.6.1.4"
257	or die "oid must be 1.3.6.1.4";	256	or die "oid must be 1.3.6.1.4";
258		257
259	=item $oid = ber_is_oid $tuple	258	=item $oid = ber_is_oid $tuple
…		…
287	use common::sense;	286	use common::sense;
288		287
289	use XSLoader ();	288	use XSLoader ();
290	use Exporter qw(import);	289	use Exporter qw(import);
291		290
292	our $VERSION = 0.2;	291	our $VERSION;
293		292
		293	BEGIN {
		294	$VERSION = 0.8;
294	XSLoader::load __PACKAGE__, $VERSION;	295	XSLoader::load __PACKAGE__, $VERSION;
		296	}
295		297
296	our %EXPORT_TAGS = (	298	our %EXPORT_TAGS = (
297	const => [qw(	299	const => [qw(
298	BER_CLASS BER_TAG BER_CONSTRUCTED BER_DATA	300	BER_CLASS BER_TAG BER_CONSTRUCTED BER_DATA
299		301
300	ASN_BOOLEAN ASN_INTEGER32 ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER ASN_TAG_BER ASN_TAG_MASK	302	ASN_BOOLEAN ASN_INTEGER32 ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER
301	ASN_CONSTRUCTED ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE ASN_CLASS_MASK ASN_CLASS_SHIFT	303	ASN_OBJECT_DESCRIPTOR ASN_OID ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED
302	ASN_SEQUENCE	304	ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING
303		305	ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING
		306	ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING
		307	ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING
		308
		309	ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE
		310
		311	BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT
		312	BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL
		313	BER_TYPE_IPADDRESS BER_TYPE_CROAK
		314	)],
		315	const_snmp => [qw(
304	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64	316	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
305	)],	317	)],
306	encode => [qw(	318	encode => [qw(
307	ber_decode	319	ber_decode
308	ber_is ber_is_seq ber_is_i32 ber_is_oid	320	ber_is ber_is_seq ber_is_i32 ber_is_oid
309	)],	321	)],
310	decode => [qw(	322	decode => [qw(
311	ber_encode	323	ber_encode
		324	ber_i32
312	)],	325	)],
313	);	326	);
314		327
315	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;	328	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;
316		329
317	$EXPORT_TAGS{all} = \@EXPORT_OK;	330	$EXPORT_TAGS{all} = \@EXPORT_OK;
318		331
		332	=head1 PROFILES
		333
		334	While any BER data can be correctly encoded and decoded out of the box, it
		335	can be inconvenient to have to manually decode some values into a "better"
		336	format: for instance, SNMP TimeTicks values are decoded into the raw octet
		337	strings of their BER representation, which is quite hard to decode. With
		338	profiles, you can change which class/tag combinations map to which decoder
		339	function inside C<ber_decode> (and of course also which encoder functions
		340	are used in C<ber_encode>).
		341
		342	This works by mapping specific class/tag combinations to an internal "ber
		343	type".
		344
		345	The default profile supports the standard ASN.1 types, but no
		346	application-specific ones. This means that class/tag combinations not in
		347	the base set of ASN.1 are decoded into their raw octet strings.
		348
		349	C<Convert::BER::XS> defines two profile variables you can use out of the box:
		350
		351	=over
		352
		353	=item C<$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
319	1;	494	1;
320		495
321	=head2 BUGS / SHORTCOMINGs	496	=head2 LIMITATIONS
322		497
323	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
324	tags for Unsigned32 and so on. More configurability is needed, and, if	499	only when your perl supports those.
325	ever implemented, will come in a form similar to how L<JSON::XS> and	500
326	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.
327		512
328	=head1 AUTHOR	513	=head1 AUTHOR
329		514
330	Marc Lehmann <schmorp@schmorp.de>	515	Marc Lehmann <schmorp@schmorp.de>
331	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 1.8 by root, Fri Apr 19 20:42:31 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 1.8 by root, Fri Apr 19 20:42:31 2019 UTC vs.
Revision 1.18 by root, Sat Apr 20 13:48:53 2019 UTC