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

Comparing Convert-BER-XS/XS.pm (file contents):
Revision 1.1 by root, Fri Apr 19 16:19:36 2019 UTC vs.
Revision 1.34 by root, Sat Apr 20 18:38:33 2019 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	Convert::BER::XS - I<very> low level BER decoding	3	Convert::BER::XS - I<very> low level BER en-/decoding
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
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, $Convert::BER::XS::SNMP_PROFILE
10	or die "unable to decode SNMP v1/v2c Message";	10	or die "unable to decode SNMP message";
		11
		12	# The above results in a data structure consisting of
		13	# (class, tag, flags, data)
		14	# tuples. Below is such a message, SNMPv1 trap
		15	# with a Cisco mac change notification.
		16	# Did you know that Cisco is in the news almost
		17	# every week because of some backdoor password
		18	# or other extremely stupid security bug?
		19
		20	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1,
		21	[
		22	[ ASN_UNIVERSAL, ASN_INTEGER, 0, 0 ], # snmp version 1
		23	[ ASN_UNIVERSAL, 4, 0, "public" ], # community
		24	[ ASN_CONTEXT, 4, 1, # CHOICE, constructed - trap PDU
		25	[
		26	[ ASN_UNIVERSAL, ASN_OBJECT_IDENTIFIER, 0, "1.3.6.1.4.1.9.9.215.2" ], # enterprise oid
		27	[ ASN_APPLICATION, SNMP_IPADDRESS, 0, "10.0.0.1" ], # SNMP IpAddress
		28	[ ASN_UNIVERSAL, ASN_INTEGER, 0, 6 ], # generic trap
		29	[ ASN_UNIVERSAL, ASN_INTEGER, 0, 1 ], # specific trap
		30	[ ASN_APPLICATION, SNMP_TIMETICKS, 0, 1817903850 ], # SNMP TimeTicks
		31	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # the varbindlist
		32	[
		33	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # a single varbind, "key value" pair
		34	[
		35	[ ASN_UNIVERSAL, ASN_OBJECT_IDENTIFIER, 0, "1.3.6.1.4.1.9.9.215.1.1.8.1.2.1" ],
		36	[ ASN_UNIVERSAL, ASN_OCTET_STRING, 0, "...data..." # the value
		37	]
		38	]
		39	],
		40	...
		41
		42	# let's decode it a bit with some helper functions
11		43
12	my $msg = ber_is_seq $ber	44	my $msg = ber_is_seq $ber
13	or die "SNMP message does not start with a sequence";	45	or die "SNMP message does not start with a sequence";
14		46
15	ber_is $msg->[0], ASN_UNIVERSAL, ASN_INTEGER32, 0	47	ber_is $msg->[0], ASN_UNIVERSAL, ASN_INTEGER, 0
16	or die "SNMP message does not start with snmp version\n";	48	or die "SNMP message does not start with snmp version\n";
17		49
		50	# message is SNMP v1 or v2c?
18	if ($msg->[0][BER_DATA] == 0 \|\| $msg->[0][BER_DATA] == 1) {	51	if ($msg->[0][BER_DATA] == 0 \|\| $msg->[0][BER_DATA] == 1) {
		52
19	# message is SNMP v1 or v2c	53	# message is v1 trap?
20
21	if (ber_is $msg->[2], ASN_CONTEXT, 4, 1) {	54	if (ber_is $msg->[2], ASN_CONTEXT, 4, 1) {
22	# message is v1 trap
23	my $trap = $msg->[2][BER_DATA];	55	my $trap = $msg->[2][BER_DATA];
24		56
25	# check whether trap is a cisco mac notification mac changed message	57	# check whether trap is a cisco mac notification mac changed message
26	if (	58	if (
27	(ber_is_oid $trap->[0], "1.3.6.1.4.1.9.9.215.2") # cmnInterfaceObjects	59	(ber_is_oid $trap->[0], "1.3.6.1.4.1.9.9.215.2") # cmnInterfaceObjects
28	and (ber_is_i32 $trap->[2], 6)	60	and (ber_is_int $trap->[2], 6)
29	and (ber_is_i32 $trap->[3], 1) # mac changed msg	61	and (ber_is_int $trap->[3], 1) # mac changed msg
30	) {	62	) {
31	... and so on	63	... and so on
32		64
		65	# finally, let's encode it again and hope it results in the same bit pattern
		66
		67	my $buf = ber_encode $ber, $Convert::BER::XS::SNMP_PROFILE;
		68
33	=head1 DESCRIPTION	69	=head1 DESCRIPTION
34		70
		71	WARNING: Before release 1.0, the API is not considered stable in any way.
		72
35	This module implements a I<very> low level BER/DER decoder, and in the	73	This module implements a I<very> low level BER/DER en-/decoder.
36	future, probably also an encoder (tell me if you want an encoder, this
37	might speed up the process of getting one).
38		74
39	If is tuned for low memory and high speed, while still maintaining some	75	It is tuned for low memory and high speed, while still maintaining some
40	level of user-friendlyness.	76	level of user-friendlyness.
41		77
42	Currently, not much is documented, as this is an initial release to	78	=head2 EXPORT TAGS AND CONSTANTS
43	reserve CPAN namespace, stay tuned for a few days.	79
		80	By default this module doesn't export any symbols, but if you don't want
		81	to break your keyboard, editor or eyesight with extremely long names, I
		82	recommend importing the C<:all> tag. Still, you can selectively import
		83	things.
		84
		85	=over
		86
		87	=item C<:all>
		88
		89	All of the below. Really. Recommended for at least first steps, or if you
		90	don't care about a few kilobytes of wasted memory (and namespace).
		91
		92	=item C<:const>
		93
		94	All of the strictly ASN.1-related constants defined by this module, the
		95	same as C<:const_asn :const_index>. Notably, this does not contain
		96	C<:const_ber_type> and C<:const_snmp>.
		97
		98	A good set to get everything you need to decode and match BER data would be
		99	C<:decode :const>.
		100
		101	=item C<:const_index>
		102
		103	The BER tuple array index constants:
		104
		105	BER_CLASS BER_TAG BER_FLAGS BER_DATA
		106
		107	=item C<:const_asn>
		108
		109	ASN class values (these are C<0>, C<1>, C<2> and C<3>, respectively -
		110	exactly thw two topmost bits from the identifier octet shifted 6 bits to
		111	the right):
		112
		113	ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE
		114
		115	ASN tag values (some of which are aliases, such as C<ASN_OID>). Their
		116	numerical value corresponds exactly to the numbers used in BER/X.690.
		117
		118	ASN_BOOLEAN ASN_INTEGER ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER
		119	ASN_OBJECT_DESCRIPTOR ASN_OID ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED
		120	ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING
		121	ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING
		122	ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING
		123	ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING
		124
		125	=item C<:const_ber_type>
		126
		127	The BER type constants, explained in the PROFILES section.
		128
		129	BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT
		130	BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL
		131	BER_TYPE_IPADDRESS BER_TYPE_CROAK
		132
		133	=item C<:const_snmp>
		134
		135	Constants only relevant to SNMP. These are the tag values used by SNMP in
		136	the C<ASN_APPLICATION> namespace and have the exact numerical value as in
		137	BER/RFC 2578.
		138
		139	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_GAUGE32
		140	SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
		141
		142	=item C<:decode>
		143
		144	C<ber_decode> and the match helper functions:
		145
		146	ber_decode ber-decode_prefix
		147	ber_is ber_is_seq ber_is_int ber_is_oid
		148
		149	=item C<:encode>
		150
		151	C<ber_encode> and the construction helper functions:
		152
		153	ber_encode
		154	ber_int
		155
		156	=back
		157
		158	=head2 ASN.1/BER/DER/... BASICS
		159
		160	ASN.1 is a strange language that can be used to describe protocols and
		161	data structures. It supports various mappings to JSON, XML, but most
		162	importantly, to a various binary encodings such as BER, that is the topic
		163	of this module, and is used in SNMP, LDAP or X.509 for example.
		164
		165	While ASN.1 defines a schema that is useful to interpret encoded data,
		166	the BER encoding is actually somewhat self-describing: you might not know
		167	whether something is a string or a number or a sequence or something else,
		168	but you can nevertheless decode the overall structure, even if you end up
		169	with just a binary blob for the actual value.
		170
		171	This works because BER values are tagged with a type and a namespace,
		172	and also have a flag that says whether a value consists of subvalues (is
		173	"constructed") or not (is "primitive").
		174
		175	Tags are simple integers, and ASN.1 defines a somewhat weird assortment
		176	of those - for example, you have one integers and 16(!) different
		177	string types, but there is no Unsigned32 type for example. Different
		178	applications work around this in different ways, for example, SNMP defines
		179	application-specific Gauge32, Counter32 and Unsigned32, which are mapped
		180	to two different tags: you can distinguish between Counter32 and the
		181	others, but not between Gause32 and Unsigned32, without the ASN.1 schema.
		182
		183	Ugh.
		184
		185	=head2 DECODED BER REPRESENTATION
		186
		187	This module represents every BER value as a 4-element tuple (actually an
		188	array-reference):
		189
		190	[CLASS, TAG, FLAGS, DATA]
		191
		192	For example:
		193
		194	[ASN_UNIVERSAL, ASN_INTEGER, 0, 177] # the integer 177
		195	[ASN_UNIVERSAL, ASN_OCTET_STRING, 0, "john"] # the string "john"
		196	[ASN_UNIVERSAL, ASN_OID, 0, "1.3.6.133"] # some OID
		197	[ASN_UNIVERSAL, ASN_SEQUENCE, 1, [ [ASN_UNIVERSAL... # a sequence
		198
		199	To avoid non-descriptive hardcoded array index numbers, this module
		200	defines symbolic constants to access these members: C<BER_CLASS>,
		201	C<BER_TAG>, C<BER_FLAGS> and C<BER_DATA>.
		202
		203	Also, the first three members are integers with a little caveat: for
		204	performance reasons, these are readonly and shared, so you must not modify
		205	them (increment, assign to them etc.) in any way. You may modify the
		206	I<DATA> member, and you may re-assign the array itself, e.g.:
		207
		208	$ber = ber_decode $binbuf;
		209
		210	# the following is NOT legal:
		211	$ber->[BER_CLASS] = ASN_PRIVATE; # ERROR, CLASS/TAG/FLAGS are READ ONLY(!)
		212
		213	# but all of the following are fine:
		214	$ber->[BER_DATA] = "string";
		215	$ber->[BER_DATA] = [ASN_UNIVERSAL, ASN_INTEGER, 0, 123];
		216	@$ber = (ASN_APPLICATION, SNMP_TIMETICKS, 0, 1000);
		217
		218	I<CLASS> is something like a namespace for I<TAG>s - there is the
		219	C<ASN_UNIVERSAL> namespace which defines tags common to all ASN.1
		220	implementations, the C<ASN_APPLICATION> namespace which defines tags for
		221	specific applications (for example, the SNMP C<Unsigned32> type is in this
		222	namespace), a special-purpose context namespace (C<ASN_CONTEXT>, used e.g.
		223	for C<CHOICE>) and a private namespace (C<ASN_PRIVATE>).
		224
		225	The meaning of the I<TAG> depends on the namespace, and defines a
		226	(partial) interpretation of the data value. For example, SNMP defines
		227	extra tags in the C<ASN_APPLICATION> namespace, and to take full advantage
		228	of these, you need to tell this module how to handle those via profiles.
		229
		230	The most common tags in the C<ASN_UNIVERSAL> namespace are
		231	C<ASN_INTEGER>, C<ASN_BIT_STRING>, C<ASN_NULL>, C<ASN_OCTET_STRING>,
		232	C<ASN_OBJECT_IDENTIFIER>, C<ASN_SEQUENCE>, C<ASN_SET> and
		233	C<ASN_IA5_STRING>.
		234
		235	The most common tags in SNMP's C<ASN_APPLICATION> namespace are
		236	C<SNMP_COUNTER32>, C<SNMP_UNSIGNED32>, C<SNMP_TIMETICKS> and
		237	C<SNMP_COUNTER64>.
		238
		239	The I<FLAGS> value is really just a boolean at this time (but might
		240	get extended) - if it is C<0>, the value is "primitive" and contains
		241	no subvalues, kind of like a non-reference perl scalar. If it is C<1>,
		242	then the value is "constructed" which just means it contains a list of
		243	subvalues which this module will en-/decode as BER tuples themselves.
		244
		245	The I<DATA> value is either a reference to an array of further tuples
		246	(if the value is I<FLAGS>), some decoded representation of the value, if
		247	this module knows how to decode it (e.g. for the integer types above) or
		248	a binary string with the raw octets if this module doesn't know how to
		249	interpret the namespace/tag.
		250
		251	Thus, you can always decode a BER data structure and at worst you get a
		252	string in place of some nice decoded value.
		253
		254	See the SYNOPSIS for an example of such an encoded tuple representation.
		255
		256	=head2 DECODING AND ENCODING
		257
		258	=over
		259
		260	=item $tuple = ber_decode $bindata[, $profile]
		261
		262	Decodes binary BER data in C<$bindata> and returns the resulting BER
		263	tuple. Croaks on any decoding error, so the returned C<$tuple> is always
		264	valid.
		265
		266	How tags are interpreted is defined by the second argument, which must
		267	be a C<Convert::BER::XS::Profile> object. If it is missing, the default
		268	profile will be used (C<$Convert::BER::XS::DEFAULT_PROFILE>).
		269
		270	In addition to rolling your own, this module provides a
		271	C<$Convert::BER::XS::SNMP_PROFILE> that knows about the additional SNMP
		272	types.
		273
		274	Example: decode a BER blob using the default profile - SNMP values will be
		275	decided as raw strings.
		276
		277	$tuple = ber_decode $data;
		278
		279	Example: as above, but use the provided SNMP profile.
		280
		281	$tuple = ber_encode $data, $Convert::BER::XS::SNMP_PROFILE;
		282
		283	=item ($tuple, $bytes) = ber_decode_prefix $bindata[, $profile]
		284
		285	Works like C<ber_decode>, except it doesn't croak when there is data after
		286	the BER data, but instead returns the decoded value and the number of
		287	bytes it decoded.
		288
		289	This is useful when you have BER data at the start of a buffer and other
		290	data after, and you need to find the length.
		291
		292	Also, since BER is self-delimited, this can be used to decode multiple BER
		293	values joined together.
		294
		295	=item $bindata = ber_encode $tuple[, $profile]
		296
		297	Encodes the BER tuple into a BER/DER data structure. AS with
		298	Cyber_decode>, an optional profile can be given.
		299
		300	The encoded data should be both BER and DER ("shortest form") compliant
		301	unless the input says otherwise (e.g. it uses constructed strings).
		302
		303	=back
		304
		305	=head2 HELPER FUNCTIONS
		306
		307	Working with a 4-tuple for every value can be annoying. Or, rather, I<is>
		308	annoying. To reduce this a bit, this module defines a number of helper
		309	functions, both to match BER tuples and to construct BER tuples:
		310
		311	=head3 MATCH HELPERS
		312
		313	These functions accept a BER tuple as first argument and either partially
		314	or fully match it. They often come in two forms, one which exactly matches
		315	a value, and one which only matches the type and returns the value.
		316
		317	They do check whether valid tuples are passed in and croak otherwise. As
		318	a ease-of-use exception, they usually also accept C<undef> instead of a
		319	tuple reference, in which case they silently fail to match.
		320
		321	=over
		322
		323	=item $bool = ber_is $tuple, $class, $tag, $flags, $data
		324
		325	This takes a BER C<$tuple> and matches its elements against the provided
		326	values, all of which are optional - values that are either missing or
		327	C<undef> will be ignored, the others will be matched exactly (e.g. as if
		328	you used C<==> or C<eq> (for C<$data>)).
		329
		330	Some examples:
		331
		332	ber_is $tuple, ASN_UNIVERSAL, ASN_SEQUENCE, 1
		333	orf die "tuple is not an ASN SEQUENCE";
		334
		335	ber_is $tuple, ASN_UNIVERSAL, ASN_NULL
		336	or die "tuple is not an ASN NULL value";
		337
		338	ber_is $tuple, ASN_UNIVERSAL, ASN_INTEGER, 0, 50
		339	or die "BER integer must be 50";
		340
		341	=item $seq = ber_is_seq $tuple
		342
		343	Returns the sequence members (the array of subvalues) if the C<$tuple> is
		344	an ASN SEQUENCE, i.e. the C<BER_DATA> member. If the C<$tuple> is not a
		345	sequence it returns C<undef>. For example, SNMP version 1/2c/3 packets all
		346	consist of an outer SEQUENCE value:
		347
		348	my $ber = ber_decode $snmp_data;
		349
		350	my $snmp = ber_is_seq $ber
		351	or die "SNMP packet invalid: does not start with SEQUENCE";
		352
		353	# now we know $snmp is a sequence, so decode the SNMP version
		354
		355	my $version = ber_is_int $snmp->[0]
		356	or die "SNMP packet invalid: does not start with version number";
		357
		358	=item $bool = ber_is_int $tuple, $int
		359
		360	Returns a true value if the C<$tuple> represents an ASN INTEGER with
		361	the value C<$int>.
		362
		363	=item $int = ber_is_int $tuple
		364
		365	Returns true (and extracts the integer value) if the C<$tuple> is an
		366	C<ASN_INTEGER>. For C<0>, this function returns a special value that is 0
		367	but true.
		368
		369	=item $bool = ber_is_oid $tuple, $oid_string
		370
		371	Returns true if the C<$tuple> represents an ASN_OBJECT_IDENTIFIER
		372	that exactly matches C<$oid_string>. Example:
		373
		374	ber_is_oid $tuple, "1.3.6.1.4"
		375	or die "oid must be 1.3.6.1.4";
		376
		377	=item $oid = ber_is_oid $tuple
		378
		379	Returns true (and extracts the OID string) if the C<$tuple> is an ASN
		380	OBJECT IDENTIFIER. Otherwise, it returns C<undef>.
		381
		382	=back
		383
		384	=head3 CONSTRUCTION HELPERS
		385
		386	=over
		387
		388	=item $tuple = ber_int $value
		389
		390	Constructs a new C<ASN_INTEGER> tuple.
		391
		392	=back
		393
		394	=head2 RELATIONSHIP TO L<Convert::BER> and L<Convert::ASN1>
		395
		396	This module is I<not> the XS version of L<Convert::BER>, but a different
		397	take at doing the same thing. I imagine this module would be a good base
		398	for speeding up either of these, or write a similar module, or write your
		399	own LDAP or SNMP module for example.
44		400
45	=cut	401	=cut
46		402
47	package Convert::BER::XS;	403	package Convert::BER::XS;
48		404
49	use common::sense;	405	use common::sense;
50		406
51	use XSLoader ();	407	use XSLoader ();
52	use Exporter qw(import);	408	use Exporter qw(import);
53		409
		410	our $VERSION;
		411
		412	BEGIN {
54	our $VERSION = '0.0';	413	$VERSION = 0.9;
55
56	XSLoader::load __PACKAGE__, $VERSION;	414	XSLoader::load __PACKAGE__, $VERSION;
		415	}
57		416
58	our %EXPORT_TAGS = (	417	our %EXPORT_TAGS = (
59	all => [qw(	418	const_index => [qw(
60	ber_decode	419	BER_CLASS BER_TAG BER_FLAGS BER_DATA
		420	)],
		421	const_asn => [qw(
		422	ASN_BOOLEAN ASN_INTEGER ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER
		423	ASN_OBJECT_DESCRIPTOR ASN_OID ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED
		424	ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING
		425	ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING
		426	ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING
		427	ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING
		428
		429	ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE
		430	)],
		431	const_ber_type => [qw(
		432	BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT
		433	BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL
		434	BER_TYPE_IPADDRESS BER_TYPE_CROAK
		435	)],
		436	const_snmp => [qw(
		437	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_GAUGE32 SNMP_UNSIGNED32
		438	SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
		439	)],
		440	decode => [qw(
		441	ber_decode ber_decode_prefix
61	ber_is ber_is_seq ber_is_i32 ber_is_oid	442	ber_is ber_is_seq ber_is_int ber_is_oid
62	BER_CLASS BER_TAG BER_CONSTRUCTED BER_DATA	443	)],
63	ASN_BOOLEAN ASN_INTEGER32 ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER ASN_TAG_BER ASN_TAG_MASK	444	encode => [qw(
64	ASN_CONSTRUCTED ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE ASN_CLASS_MASK ASN_CLASS_SHIFT	445	ber_encode
65	ASN_SEQUENCE ASN_IPADDRESS ASN_COUNTER32 ASN_UNSIGNED32 ASN_TIMETICKS ASN_OPAQUE ASN_COUNTER64	446	ber_int
66	)],	447	)],
67	);	448	);
68		449
69	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;	450	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;
70		451
		452	$EXPORT_TAGS{all} = \@EXPORT_OK;
		453	$EXPORT_TAGS{const} = [map @{ $EXPORT_TAGS{$_} }, qw(const_index const_asn)];
		454
		455	=head1 PROFILES
		456
		457	While any BER data can be correctly encoded and decoded out of the box, it
		458	can be inconvenient to have to manually decode some values into a "better"
		459	format: for instance, SNMP TimeTicks values are decoded into the raw octet
		460	strings of their BER representation, which is quite hard to decode. With
		461	profiles, you can change which class/tag combinations map to which decoder
		462	function inside C<ber_decode> (and of course also which encoder functions
		463	are used in C<ber_encode>).
		464
		465	This works by mapping specific class/tag combinations to an internal "ber
		466	type".
		467
		468	The default profile supports the standard ASN.1 types, but no
		469	application-specific ones. This means that class/tag combinations not in
		470	the base set of ASN.1 are decoded into their raw octet strings.
		471
		472	C<Convert::BER::XS> defines two profile variables you can use out of the box:
		473
		474	=over
		475
		476	=item C<$Convert::BER::XS::DEFAULT_PROFILE>
		477
		478	This is the default profile, i.e. the profile that is used when no
		479	profile is specified for de-/encoding.
		480
		481	You can modify it, but remember that this modifies the defaults for all
		482	callers that rely on the default profile.
		483
		484	=item C<$Convert::BER::XS::SNMP_PROFILE>
		485
		486	A profile with mappings for SNMP-specific application tags added. This is
		487	useful when de-/encoding SNMP data.
		488
		489	Example:
		490
		491	$ber = ber_decode $data, $Convert::BER::XS::SNMP_PROFILE;
		492
		493	=back
		494
		495	=head2 The Convert::BER::XS::Profile class
		496
		497	=over
		498
		499	=item $profile = new Convert::BER::XS::Profile
		500
		501	Create a new profile. The profile will be identical to the default
		502	profile.
		503
		504	=item $profile->set ($class, $tag, $type)
		505
		506	Sets the mapping for the given C<$class>/C<$tag> combination to C<$type>,
		507	which must be one of the C<BER_TYPE_*> constants.
		508
		509	Note that currently, the mapping is stored in a flat array, so large
		510	values of C<$tag> will consume large amounts of memory.
		511
		512	Example:
		513
		514	$profile = new Convert::BER::XS::Profile;
		515	$profile->set (ASN_APPLICATION, SNMP_COUNTER32, BER_TYPE_INT);
		516	$ber = ber_decode $data, $profile;
		517
		518	=item $type = $profile->get ($class, $tag)
		519
		520	Returns the BER type mapped to the given C<$class>/C<$tag> combination.
		521
		522	=back
		523
		524	=head2 BER TYPES
		525
		526	This lists the predefined BER types - you can map any C<CLASS>/C<TAG>
		527	combination to any C<BER_TYPE_*>.
		528
		529	=over
		530
		531	=item C<BER_TYPE_BYTES>
		532
		533	The raw octets of the value. This is the default type for unknown tags and
		534	de-/encodes the value as if it were an octet string, i.e. by copying the
		535	raw bytes.
		536
		537	=item C<BER_TYPE_UTF8>
		538
		539	Like C<BER_TYPE_BYTES>, but decodes the value as if it were a UTF-8 string
		540	(without validation!) and encodes a perl unicode string into a UTF-8 BER
		541	string.
		542
		543	=item C<BER_TYPE_UCS2>
		544
		545	Similar to C<BER_TYPE_UTF8>, but treats the BER value as UCS-2 encoded
		546	string.
		547
		548	=item C<BER_TYPE_UCS4>
		549
		550	Similar to C<BER_TYPE_UTF8>, but treats the BER value as UCS-4 encoded
		551	string.
		552
		553	=item C<BER_TYPE_INT>
		554
		555	Encodes and decodes a BER integer value to a perl integer scalar. This
		556	should correctly handle 64 bit signed and unsigned values.
		557
		558	=item C<BER_TYPE_OID>
		559
		560	Encodes and decodes an OBJECT IDENTIFIER into dotted form without leading
		561	dot, e.g. C<1.3.6.1.213>.
		562
		563	=item C<BER_TYPE_RELOID>
		564
		565	Same as C<BER_TYPE_OID> but uses relative object identifier
		566	encoding: ASN.1 has this hack of encoding the first two OID components
		567	into a single integer in a weird attempt to save an insignificant amount
		568	of space in an otherwise wasteful encoding, and relative OIDs are
		569	basically OIDs without this hack. The practical difference is that the
		570	second component of an OID can only have the values 1..40, while relative
		571	OIDs do not have this restriction.
		572
		573	=item C<BER_TYPE_NULL>
		574
		575	Decodes an C<ASN_NULL> value into C<undef>, and always encodes a
		576	C<ASN_NULL> type, regardless of the perl value.
		577
		578	=item C<BER_TYPE_BOOL>
		579
		580	Decodes an C<ASN_BOOLEAN> value into C<0> or C<1>, and encodes a perl
		581	boolean value into an C<ASN_BOOLEAN>.
		582
		583	=item C<BER_TYPE_REAL>
		584
		585	Decodes/encodes a BER real value. NOT IMPLEMENTED.
		586
		587	=item C<BER_TYPE_IPADDRESS>
		588
		589	Decodes/encodes a four byte string into an IPv4 dotted-quad address string
		590	in Perl. Given the obsolete nature of this type, this is a low-effort
		591	implementation that simply uses C<sprintf> and C<sscanf>-style conversion,
		592	so it won't handle all string forms supported by C<inet_aton> for example.
		593
		594	=item C<BER_TYPE_CROAK>
		595
		596	Always croaks when encountered during encoding or decoding - the
		597	default behaviour when encountering an unknown type is to treat it as
		598	C<BER_TYPE_BYTES>. When you don't want that but instead prefer a hard
		599	error for some types, then C<BER_TYPE_CROAK> is for you.
		600
		601	=back
		602
		603	=head2 Example Profile
		604
		605	The following creates a profile suitable for SNMP - it's exactly identical
		606	to the C<$Convert::BER::XS::SNMP_PROFILE> profile.
		607
		608	our $SNMP_PROFILE = new Convert::BER::XS::Profile;
		609
		610	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS);
		611	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT);
		612	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT);
		613	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT);
		614	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_IPADDRESS);
		615	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT);
		616
		617	=cut
		618
		619	our $DEFAULT_PROFILE = new Convert::BER::XS::Profile;
		620
		621	$DEFAULT_PROFILE->_set_default;
		622
		623	# additional SNMP application types
		624	our $SNMP_PROFILE = new Convert::BER::XS::Profile;
		625
		626	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS);
		627	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT);
		628	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT);
		629	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT);
		630	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_IPADDRESS);
		631	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT);
		632
71	1;	633	1;
		634
		635	=head2 LIMITATIONS/NOTES
		636
		637	This module can only en-/decode 64 bit signed and unsigned integers, and
		638	only when your perl supports those.
		639
		640	This module does not generally care about ranges, i.e. it will happily
		641	de-/encode 64 bit integers into an C<ASN_INTEGER> value, or a negative
		642	number into an C<SNMP_COUNTER64>.
		643
		644	OBJECT IDENTIFIEERs cannot have unlimited length, although the limit is
		645	much larger than e.g. the one imposed by SNMP or other protocols,a nd is
		646	about 4kB.
		647
		648	Indefinite length encoding is not supported.
		649
		650	Constructed strings are decoded just fine, but there should be a way to
		651	join them for convenience.
		652
		653	REAL values are not supported and will currently croak.
		654
		655	The encoder and decoder tend to accept more formats than should be
		656	strictly supported.
		657
		658	This module has undergone little to no testing so far.
		659
		660	=head2 ITHREADS SUPPORT
		661
		662	This module is unlikely to work when the (officially discouraged) ithreads
		663	are in use.
72		664
73	=head1 AUTHOR	665	=head1 AUTHOR
74		666
75	Marc Lehmann <schmorp@schmorp.de>	667	Marc Lehmann <schmorp@schmorp.de>
76	http://software.schmorp.de/pkg/Convert-BER-XS	668	http://software.schmorp.de/pkg/Convert-BER-XS

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Comparing Convert-BER-XS/XS.pm (file contents): Revision 1.1 by root, Fri Apr 19 16:19:36 2019 UTC vs. Revision 1.34 by root, Sat Apr 20 18:38:33 2019 UTC

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Comparing Convert-BER-XS/XS.pm (file contents):
Revision 1.1 by root, Fri Apr 19 16:19:36 2019 UTC vs.
Revision 1.34 by root, Sat Apr 20 18:38:33 2019 UTC