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

Comparing Convert-BER-XS/XS.pm (file contents):
Revision 1.2 by root, Fri Apr 19 16:23:00 2019 UTC vs.
Revision 1.25 by root, Sat Apr 20 15:23:26 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, # constructed, 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_CONSTRUCTED 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_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
		140
		141	=item C<:decode>
		142
		143	C<ber_decode> and the match helper functions:
		144
		145	ber_decode ber_is ber_is_seq ber_is_int ber_is_oid
		146
		147	=item C<:encode>
		148
		149	C<ber_encode> and the construction helper functions:
		150
		151	ber_encode ber_int
		152
		153	=back
		154
		155	=head2 ASN.1/BER/DER/... BASICS
		156
		157	ASN.1 is a strange language that can be used to describe protocols and
		158	data structures. It supports various mappings to JSON, XML, but most
		159	importantly, to a various binary encodings such as BER, that is the topic
		160	of this module, and is used in SNMP or LDAP for example.
		161
		162	While ASN.1 defines a schema that is useful to interpret encoded data,
		163	the BER encoding is actually somewhat self-describing: you might not know
		164	whether something is a string or a number or a sequence or something else,
		165	but you can nevertheless decode the overall structure, even if you end up
		166	with just a binary blob for the actual value.
		167
		168	This works because BER values are tagged with a type and a namespace,
		169	and also have a flag that says whether a value consists of subvalues (is
		170	"constructed") or not (is "primitive").
		171
		172	Tags are simple integers, and ASN.1 defines a somewhat weird assortment
		173	of those - for example, you have one integers and 16(!) different
		174	string types, but there is no Unsigned32 type for example. Different
		175	applications work around this in different ways, for example, SNMP defines
		176	application-specific Gauge32, Counter32 and Unsigned32, which are mapped
		177	to two different tags: you can distinguish between Counter32 and the
		178	others, but not between Gause32 and Unsigned32, without the ASN.1 schema.
		179
		180	Ugh.
		181
		182	=head2 DECODED BER REPRESENTATION
		183
		184	This module represents every BER value as a 4-element tuple (actually an
		185	array-reference):
		186
		187	[CLASS, TAG, CONSTRUCTED, DATA]
		188
		189	For example:
		190
		191	[ASN_UNIVERSAL, ASN_INTEGER, 0, 177] # the integer 177
		192	[ASN_UNIVERSAL, ASN_OCTET_STRING, 0, "john"] # the string "john"
		193	[ASN_UNIVERSAL, ASN_OID, 0, "1.3.6.133"] # some OID
		194	[ASN_UNIVERSAL, ASN_SEQUENCE, 1, [ [ASN_UNIVERSAL... # a sequence
		195
		196	To avoid non-descriptive hardcoded array index numbers, this module
		197	defines symbolic constants to access these members: C<BER_CLASS>,
		198	C<BER_TAG>, C<BER_CONSTRUCTED> and C<BER_DATA>.
		199
		200	Also, the first three members are integers with a little caveat: for
		201	performance reasons, these are readonly and shared, so you must not modify
		202	them (increment, assign to them etc.) in any way. You may modify the
		203	I<DATA> member, and you may re-assign the array itself, e.g.:
		204
		205	$ber = ber_decode $binbuf;
		206
		207	# the following is NOT legal:
		208	$ber->[BER_CLASS] = ASN_PRIVATE; # ERROR, CLASS/TAG/CONSTRUCTED are READ ONLY(!)
		209
		210	# but all of the following are fine:
		211	$ber->[BER_DATA] = "string";
		212	$ber->[BER_DATA] = [ASN_UNIVERSAL, ASN_INTEGER, 0, 123];
		213	@$ber = (ASN_APPLICATION, SNMP_TIMETICKS, 0, 1000);
		214
		215	I<CLASS> is something like a namespace for I<TAG>s - there is the
		216	C<ASN_UNIVERSAL> namespace which defines tags common to all ASN.1
		217	implementations, the C<ASN_APPLICATION> namespace which defines tags for
		218	specific applications (for example, the SNMP C<Unsigned32> type is in this
		219	namespace), a special-purpose context namespace (C<ASN_CONTEXT>, used e.g.
		220	for C<CHOICE>) and a private namespace (C<ASN_PRIVATE>).
		221
		222	The meaning of the I<TAG> depends on the namespace, and defines a
		223	(partial) interpretation of the data value. For example, SNMP defines
		224	extra tags in the C<ASN_APPLICATION> namespace, and to take full advantage
		225	of these, you need to tell this module how to handle those via profiles.
		226
		227	The most common tags in the C<ASN_UNIVERSAL> namespace are
		228	C<ASN_INTEGER>, C<ASN_BIT_STRING>, C<ASN_NULL>, C<ASN_OCTET_STRING>,
		229	C<ASN_OBJECT_IDENTIFIER>, C<ASN_SEQUENCE>, C<ASN_SET> and
		230	C<ASN_IA5_STRING>.
		231
		232	The most common tags in SNMP's C<ASN_APPLICATION> namespace are
		233	C<SNMP_COUNTER32>, C<SNMP_UNSIGNED32>, C<SNMP_TIMETICKS> and
		234	C<SNMP_COUNTER64>.
		235
		236	The I<CONSTRUCTED> flag is really just a boolean - if it is false,
		237	the value is "primitive" and contains no subvalues, kind of like a
		238	non-reference perl scalar. If it is true, then the value is "constructed"
		239	which just means it contains a list of subvalues which this module will
		240	en-/decode as BER tuples themselves.
		241
		242	The I<DATA> value is either a reference to an array of further tuples (if
		243	the value is I<CONSTRUCTED>), some decoded representation of the value,
		244	if this module knows how to decode it (e.g. for the integer types above)
		245	or a binary string with the raw octets if this module doesn't know how to
		246	interpret the namespace/tag.
		247
		248	Thus, you can always decode a BER data structure and at worst you get a
		249	string in place of some nice decoded value.
		250
		251	See the SYNOPSIS for an example of such an encoded tuple representation.
		252
		253	=head2 DECODING AND ENCODING
		254
		255	=over
		256
		257	=item $tuple = ber_decoded $bindata[, $profile]
		258
		259	Decodes binary BER data in C<$bindata> and returns the resulting BER
		260	tuple. Croaks on any decoding error, so the returned C<$tuple> is always
		261	valid.
		262
		263	How tags are interpreted is defined by the second argument, which must
		264	be a C<Convert::BER::XS::Profile> object. If it is missing, the default
		265	profile will be used (C<$Convert::BER::XS::DEFAULT_PROFILE>).
		266
		267	In addition to rolling your own, this module provides a
		268	C<$Convert::BER::XS::SNMP_PROFILE> that knows about the additional SNMP
		269	types.
		270
		271	Example: decode a BER blob using the default profile - SNMP values will be
		272	decided as raw strings.
		273
		274	$tuple = ber_decode $data;
		275
		276	Example: as above, but use the provided SNMP profile.
		277
		278	$tuple = ber_encode $data, $Convert::BER::XS::SNMP_PROFILE;
		279
		280	=item $bindata = ber_encode $tuple[, $profile]
		281
		282	Encodes the BER tuple into a BER/DER data structure. AS with
		283	Cyber_decode>, an optional profile can be given.
		284
		285	=back
		286
		287	=head2 HELPER FUNCTIONS
		288
		289	Working with a 4-tuple for every value can be annoying. Or, rather, I<is>
		290	annoying. To reduce this a bit, this module defines a number of helper
		291	functions, both to match BER tuples and to construct BER tuples:
		292
		293	=head3 MATCH HELPERS
		294
		295	These functions accept a BER tuple as first argument and either partially
		296	or fully match it. They often come in two forms, one which exactly matches
		297	a value, and one which only matches the type and returns the value.
		298
		299	They do check whether valid tuples are passed in and croak otherwise. As
		300	a ease-of-use exception, they usually also accept C<undef> instead of a
		301	tuple reference, in which case they silently fail to match.
		302
		303	=over
		304
		305	=item $bool = ber_is $tuple, $class, $tag, $constructed, $data
		306
		307	This takes a BER C<$tuple> and matches its elements against the provided
		308	values, all of which are optional - values that are either missing or
		309	C<undef> will be ignored, the others will be matched exactly (e.g. as if
		310	you used C<==> or C<eq> (for C<$data>)).
		311
		312	Some examples:
		313
		314	ber_is $tuple, ASN_UNIVERSAL, ASN_SEQUENCE, 1
		315	orf die "tuple is not an ASN SEQUENCE";
		316
		317	ber_is $tuple, ASN_UNIVERSAL, ASN_NULL
		318	or die "tuple is not an ASN NULL value";
		319
		320	ber_is $tuple, ASN_UNIVERSAL, ASN_INTEGER, 0, 50
		321	or die "BER integer must be 50";
		322
		323	=item $seq = ber_is_seq $tuple
		324
		325	Returns the sequence members (the array of subvalues) if the C<$tuple> is
		326	an ASN SEQUENCE, i.e. the C<BER_DATA> member. If the C<$tuple> is not a
		327	sequence it returns C<undef>. For example, SNMP version 1/2c/3 packets all
		328	consist of an outer SEQUENCE value:
		329
		330	my $ber = ber_decode $snmp_data;
		331
		332	my $snmp = ber_is_seq $ber
		333	or die "SNMP packet invalid: does not start with SEQUENCE";
		334
		335	# now we know $snmp is a sequence, so decode the SNMP version
		336
		337	my $version = ber_is_int $snmp->[0]
		338	or die "SNMP packet invalid: does not start with version number";
		339
		340	=item $bool = ber_is_int $tuple, $int
		341
		342	Returns a true value if the C<$tuple> represents an ASN INTEGER with
		343	the value C<$int>.
		344
		345	=item $int = ber_is_int $tuple
		346
		347	Returns true (and extracts the integer value) if the C<$tuple> is an
		348	C<ASN_INTEGER>. For C<0>, this function returns a special value that is 0
		349	but true.
		350
		351	=item $bool = ber_is_oid $tuple, $oid_string
		352
		353	Returns true if the C<$tuple> represents an ASN_OBJECT_IDENTIFIER
		354	that exactly matches C<$oid_string>. Example:
		355
		356	ber_is_oid $tuple, "1.3.6.1.4"
		357	or die "oid must be 1.3.6.1.4";
		358
		359	=item $oid = ber_is_oid $tuple
		360
		361	Returns true (and extracts the OID string) if the C<$tuple> is an ASN
		362	OBJECT IDENTIFIER. Otherwise, it returns C<undef>.
		363
		364	=back
		365
		366	=head3 CONSTRUCTION HELPERS
		367
		368	=over
		369
		370	=item $tuple = ber_int $value
		371
		372	Constructs a new C<ASN_INTEGER> tuple.
		373
		374	=back
44		375
45	=head2 RELATIONSHIP TO L<Convert::BER> and L<Convert::ASN1>	376	=head2 RELATIONSHIP TO L<Convert::BER> and L<Convert::ASN1>
46		377
47	This module is I<not> the XS version of L<Convert::BER>, but a different	378	This module is I<not> the XS version of L<Convert::BER>, but a different
48	take at doing the same thing. I imagine this module would be a good base	379	take at doing the same thing. I imagine this module would be a good base
49	for speeding up either fo these, or write a similar module, or write your	380	for speeding up either of these, or write a similar module, or write your
50	own LDAP or SNMP module for example.	381	own LDAP or SNMP module for example.
51		382
52	=cut	383	=cut
53		384
54	package Convert::BER::XS;	385	package Convert::BER::XS;
56	use common::sense;	387	use common::sense;
57		388
58	use XSLoader ();	389	use XSLoader ();
59	use Exporter qw(import);	390	use Exporter qw(import);
60		391
		392	our $VERSION;
		393
		394	BEGIN {
61	our $VERSION = '0.0';	395	$VERSION = 0.8;
62
63	XSLoader::load __PACKAGE__, $VERSION;	396	XSLoader::load __PACKAGE__, $VERSION;
		397	}
64		398
65	our %EXPORT_TAGS = (	399	our %EXPORT_TAGS = (
66	all => [qw(	400	const_index => [qw(
		401	BER_CLASS BER_TAG BER_CONSTRUCTED BER_DATA
		402	)],
		403	const_asn => [qw(
		404	ASN_BOOLEAN ASN_INTEGER ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER
		405	ASN_OBJECT_DESCRIPTOR ASN_OID ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED
		406	ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING
		407	ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING
		408	ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING
		409	ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING
		410
		411	ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE
		412	)],
		413	const_ber_type => [qw(
		414	BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT
		415	BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL
		416	BER_TYPE_IPADDRESS BER_TYPE_CROAK
		417	)],
		418	const_snmp => [qw(
		419	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
		420	)],
		421	decode => [qw(
67	ber_decode	422	ber_decode
68	ber_is ber_is_seq ber_is_i32 ber_is_oid	423	ber_is ber_is_seq ber_is_int ber_is_oid
69	BER_CLASS BER_TAG BER_CONSTRUCTED BER_DATA	424	)],
70	ASN_BOOLEAN ASN_INTEGER32 ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER ASN_TAG_BER ASN_TAG_MASK	425	encode => [qw(
71	ASN_CONSTRUCTED ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE ASN_CLASS_MASK ASN_CLASS_SHIFT	426	ber_encode
72	ASN_SEQUENCE ASN_IPADDRESS ASN_COUNTER32 ASN_UNSIGNED32 ASN_TIMETICKS ASN_OPAQUE ASN_COUNTER64	427	ber_int
73	)],	428	)],
74	);	429	);
75		430
76	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;	431	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;
77		432
		433	$EXPORT_TAGS{all} = \@EXPORT_OK;
		434	$EXPORT_TAGS{const} = [map @{ $EXPORT_TAGS{$_} }, qw(const_index const_asn)];
		435	use Data::Dump; ddx \%EXPORT_TAGS;
		436
		437	=head1 PROFILES
		438
		439	While any BER data can be correctly encoded and decoded out of the box, it
		440	can be inconvenient to have to manually decode some values into a "better"
		441	format: for instance, SNMP TimeTicks values are decoded into the raw octet
		442	strings of their BER representation, which is quite hard to decode. With
		443	profiles, you can change which class/tag combinations map to which decoder
		444	function inside C<ber_decode> (and of course also which encoder functions
		445	are used in C<ber_encode>).
		446
		447	This works by mapping specific class/tag combinations to an internal "ber
		448	type".
		449
		450	The default profile supports the standard ASN.1 types, but no
		451	application-specific ones. This means that class/tag combinations not in
		452	the base set of ASN.1 are decoded into their raw octet strings.
		453
		454	C<Convert::BER::XS> defines two profile variables you can use out of the box:
		455
		456	=over
		457
		458	=item C<$Convert::BER::XS::DEFAULT_PROFILE>
		459
		460	This is the default profile, i.e. the profile that is used when no
		461	profile is specified for de-/encoding.
		462
		463	You can modify it, but remember that this modifies the defaults for all
		464	callers that rely on the default profile.
		465
		466	=item C<$Convert::BER::XS::SNMP_PROFILE>
		467
		468	A profile with mappings for SNMP-specific application tags added. This is
		469	useful when de-/encoding SNMP data.
		470
		471	Example:
		472
		473	$ber = ber_decode $data, $Convert::BER::XS::SNMP_PROFILE;
		474
		475	=back
		476
		477	=head2 The Convert::BER::XS::Profile class
		478
		479	=over
		480
		481	=item $profile = new Convert::BER::XS::Profile
		482
		483	Create a new profile. The profile will be identical to the default
		484	profile.
		485
		486	=item $profile->set ($class, $tag, $type)
		487
		488	Sets the mapping for the given C<$class>/C<$tag> combination to C<$type>,
		489	which must be one of the C<BER_TYPE_*> constants.
		490
		491	Note that currently, the mapping is stored in a flat array, so large
		492	values of C<$tag> will consume large amounts of memory.
		493
		494	Example:
		495
		496	$profile = new Convert::BER::XS::Profile;
		497	$profile->set (ASN_APPLICATION, SNMP_COUNTER32, BER_TYPE_INT);
		498	$ber = ber_decode $data, $profile;
		499
		500	=item $type = $profile->get ($class, $tag)
		501
		502	Returns the BER type mapped to the given C<$class>/C<$tag> combination.
		503
		504	=back
		505
		506	=head2 BER TYPES
		507
		508	This lists the predefined BER types - you can map any C<CLASS>/C<TAG>
		509	combination to any C<BER_TYPE_*>.
		510
		511	=over
		512
		513	=item C<BER_TYPE_BYTES>
		514
		515	The raw octets of the value. This is the default type for unknown tags and
		516	de-/encodes the value as if it were an octet string, i.e. by copying the
		517	raw bytes.
		518
		519	=item C<BER_TYPE_UTF8>
		520
		521	Like C<BER_TYPE_BYTES>, but decodes the value as if it were a UTF-8 string
		522	(without validation!) and encodes a perl unicode string into a UTF-8 BER
		523	string.
		524
		525	=item C<BER_TYPE_UCS2>
		526
		527	Similar to C<BER_TYPE_UTF8>, but treats the BER value as UCS-2 encoded
		528	string.
		529
		530	=item C<BER_TYPE_UCS4>
		531
		532	Similar to C<BER_TYPE_UTF8>, but treats the BER value as UCS-4 encoded
		533	string.
		534
		535	=item C<BER_TYPE_INT>
		536
		537	Encodes and decodes a BER integer value to a perl integer scalar. This
		538	should correctly handle 64 bit signed and unsigned values.
		539
		540	=item C<BER_TYPE_OID>
		541
		542	Encodes and decodes an OBJECT IDENTIFIER into dotted form without leading
		543	dot, e.g. C<1.3.6.1.213>.
		544
		545	=item C<BER_TYPE_RELOID>
		546
		547	Same as C<BER_TYPE_OID> but uses relative object identifier
		548	encoding: ASN.1 has this hack of encoding the first two OID components
		549	into a single integer in a weird attempt to save an insignificant amount
		550	of space in an otherwise wasteful encoding, and relative OIDs are
		551	basically OIDs without this hack. The practical difference is that the
		552	second component of an OID can only have the values 1..40, while relative
		553	OIDs do not have this restriction.
		554
		555	=item C<BER_TYPE_NULL>
		556
		557	Decodes an C<ASN_NULL> value into C<undef>, and always encodes a
		558	C<ASN_NULL> type, regardless of the perl value.
		559
		560	=item C<BER_TYPE_BOOL>
		561
		562	Decodes an C<ASN_BOOLEAN> value into C<0> or C<1>, and encodes a perl
		563	boolean value into an C<ASN_BOOLEAN>.
		564
		565	=item C<BER_TYPE_REAL>
		566
		567	Decodes/encodes a BER real value. NOT IMPLEMENTED.
		568
		569	=item C<BER_TYPE_IPADDRESS>
		570
		571	Decodes/encodes a four byte string into an IPv4 dotted-quad address string
		572	in Perl. Given the obsolete nature of this type, this is a low-effort
		573	implementation that simply uses C<sprintf> and C<sscanf>-style conversion,
		574	so it won't handle all string forms supported by C<inet_aton> for example.
		575
		576	=item C<BER_TYPE_CROAK>
		577
		578	Always croaks when encountered during encoding or decoding - the
		579	default behaviour when encountering an unknown type is to treat it as
		580	C<BER_TYPE_BYTES>. When you don't want that but instead prefer a hard
		581	error for some types, then C<BER_TYPE_CROAK> is for you.
		582
		583	=back
		584
		585	=cut
		586
		587	our $DEFAULT_PROFILE = new Convert::BER::XS::Profile;
		588	our $SNMP_PROFILE = new Convert::BER::XS::Profile;
		589
		590	# additional SNMP application types
		591	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS);
		592	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT);
		593	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT);
		594	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT);
		595	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_IPADDRESS);
		596	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT);
		597
		598	$DEFAULT_PROFILE->_set_default;
		599
78	1;	600	1;
		601
		602	=head2 LIMITATIONS/NOTES
		603
		604	This module can only en-/decode 64 bit signed and unsigned integers, and
		605	only when your perl supports those.
		606
		607	This module does not generally care about ranges, i.e. it will happily
		608	de-/encode 64 bit integers into an C<ASN_INTEGER> value, or a negative
		609	number into an C<SNMP_COUNTER64>.
		610
		611	OBJECT IDENTIFIEERs cannot have unlimited length, although the limit is
		612	much larger than e.g. the one imposed by SNMP or other protocols,a nd is
		613	about 4kB.
		614
		615	REAL values are not supported and will currently croak.
		616
		617	This module has undergone little to no testing so far.
		618
		619	=head2 ITHREADS SUPPORT
		620
		621	This module is unlikely to work when the (officially discouraged) ithreads
		622	are in use.
79		623
80	=head1 AUTHOR	624	=head1 AUTHOR
81		625
82	Marc Lehmann <schmorp@schmorp.de>	626	Marc Lehmann <schmorp@schmorp.de>
83	http://software.schmorp.de/pkg/Convert-BER-XS	627	http://software.schmorp.de/pkg/Convert-BER-XS

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Comparing Convert-BER-XS/XS.pm (file contents): Revision 1.2 by root, Fri Apr 19 16:23:00 2019 UTC vs. Revision 1.25 by root, Sat Apr 20 15:23:26 2019 UTC

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Comparing Convert-BER-XS/XS.pm (file contents):
Revision 1.2 by root, Fri Apr 19 16:23:00 2019 UTC vs.
Revision 1.25 by root, Sat Apr 20 15:23:26 2019 UTC