[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 1.38 by root, Sun Apr 21 00:39:26 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, 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	# let's dump it, for debugging
		42
		43	ber_dump $ber, $Convert::BER::XS::SNMP_PROFILE;
		44
		45	# let's decode it a bit with some helper functions
11		46
12	my $msg = ber_is_seq $ber	47	my $msg = ber_is_seq $ber
13	or die "SNMP message does not start with a sequence";	48	or die "SNMP message does not start with a sequence";
14		49
15	ber_is $msg->[0], ASN_UNIVERSAL, ASN_INTEGER32, 0	50	ber_is $msg->[0], ASN_UNIVERSAL, ASN_INTEGER, 0
16	or die "SNMP message does not start with snmp version\n";	51	or die "SNMP message does not start with snmp version\n";
17		52
		53	# message is SNMP v1 or v2c?
18	if ($msg->[0][BER_DATA] == 0 \|\| $msg->[0][BER_DATA] == 1) {	54	if ($msg->[0][BER_DATA] == 0 \|\| $msg->[0][BER_DATA] == 1) {
		55
19	# message is SNMP v1 or v2c	56	# message is v1 trap?
20
21	if (ber_is $msg->[2], ASN_CONTEXT, 4, 1) {	57	if (ber_is $msg->[2], ASN_CONTEXT, 4, 1) {
22	# message is v1 trap
23	my $trap = $msg->[2][BER_DATA];	58	my $trap = $msg->[2][BER_DATA];
24		59
25	# check whether trap is a cisco mac notification mac changed message	60	# check whether trap is a cisco mac notification mac changed message
26	if (	61	if (
27	(ber_is_oid $trap->[0], "1.3.6.1.4.1.9.9.215.2") # cmnInterfaceObjects	62	(ber_is_oid $trap->[0], "1.3.6.1.4.1.9.9.215.2") # cmnInterfaceObjects
28	and (ber_is_i32 $trap->[2], 6)	63	and (ber_is_int $trap->[2], 6)
29	and (ber_is_i32 $trap->[3], 1) # mac changed msg	64	and (ber_is_int $trap->[3], 1) # mac changed msg
30	) {	65	) {
31	... and so on	66	... and so on
32		67
		68	# finally, let's encode it again and hope it results in the same bit pattern
		69
		70	my $buf = ber_encode $ber, $Convert::BER::XS::SNMP_PROFILE;
		71
33	=head1 DESCRIPTION	72	=head1 DESCRIPTION
34		73
		74	WARNING: Before release 1.0, the API is not considered stable in any way.
		75
35	This module implements a I<very> low level BER/DER decoder, and in the	76	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		77
39	If is tuned for low memory and high speed, while still maintaining some	78	It is tuned for low memory and high speed, while still maintaining some
40	level of user-friendlyness.	79	level of user-friendlyness.
41		80
42	Currently, not much is documented, as this is an initial release to	81	=head2 EXPORT TAGS AND CONSTANTS
43	reserve CPAN namespace, stay tuned for a few days.	82
		83	By default this module doesn't export any symbols, but if you don't want
		84	to break your keyboard, editor or eyesight with extremely long names, I
		85	recommend importing the C<:all> tag. Still, you can selectively import
		86	things.
		87
		88	=over
		89
		90	=item C<:all>
		91
		92	All of the below. Really. Recommended for at least first steps, or if you
		93	don't care about a few kilobytes of wasted memory (and namespace).
		94
		95	=item C<:const>
		96
		97	All of the strictly ASN.1-related constants defined by this module, the
		98	same as C<:const_asn :const_index>. Notably, this does not contain
		99	C<:const_ber_type> and C<:const_snmp>.
		100
		101	A good set to get everything you need to decode and match BER data would be
		102	C<:decode :const>.
		103
		104	=item C<:const_index>
		105
		106	The BER tuple array index constants:
		107
		108	BER_CLASS BER_TAG BER_FLAGS BER_DATA
		109
		110	=item C<:const_asn>
		111
		112	ASN class values (these are C<0>, C<1>, C<2> and C<3>, respectively -
		113	exactly thw two topmost bits from the identifier octet shifted 6 bits to
		114	the right):
		115
		116	ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE
		117
		118	ASN tag values (some of which are aliases, such as C<ASN_OID>). Their
		119	numerical value corresponds exactly to the numbers used in BER/X.690.
		120
		121	ASN_BOOLEAN ASN_INTEGER ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OID
		122	ASN_OBJECT_IDENTIFIER ASN_OBJECT_DESCRIPTOR ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED
		123	ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING
		124	ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING
		125	ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING
		126	ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING
		127
		128	=item C<:const_ber_type>
		129
		130	The BER type constants, explained in the PROFILES section.
		131
		132	BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT
		133	BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL
		134	BER_TYPE_IPADDRESS BER_TYPE_CROAK
		135
		136	=item C<:const_snmp>
		137
		138	Constants only relevant to SNMP. These are the tag values used by SNMP in
		139	the C<ASN_APPLICATION> namespace and have the exact numerical value as in
		140	BER/RFC 2578.
		141
		142	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_GAUGE32
		143	SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
		144
		145	=item C<:decode>
		146
		147	C<ber_decode> and the match helper functions:
		148
		149	ber_decode ber-decode_prefix
		150	ber_is ber_is_seq ber_is_int ber_is_oid
		151	ber_dump
		152
		153	=item C<:encode>
		154
		155	C<ber_encode> and the construction helper functions:
		156
		157	ber_encode
		158	ber_int
		159
		160	=back
		161
		162	=head2 ASN.1/BER/DER/... BASICS
		163
		164	ASN.1 is a strange language that can be used to describe protocols and
		165	data structures. It supports various mappings to JSON, XML, but most
		166	importantly, to a various binary encodings such as BER, that is the topic
		167	of this module, and is used in SNMP, LDAP or X.509 for example.
		168
		169	While ASN.1 defines a schema that is useful to interpret encoded data,
		170	the BER encoding is actually somewhat self-describing: you might not know
		171	whether something is a string or a number or a sequence or something else,
		172	but you can nevertheless decode the overall structure, even if you end up
		173	with just a binary blob for the actual value.
		174
		175	This works because BER values are tagged with a type and a namespace,
		176	and also have a flag that says whether a value consists of subvalues (is
		177	"constructed") or not (is "primitive").
		178
		179	Tags are simple integers, and ASN.1 defines a somewhat weird assortment
		180	of those - for example, you have one integers and 16(!) different
		181	string types, but there is no Unsigned32 type for example. Different
		182	applications work around this in different ways, for example, SNMP defines
		183	application-specific Gauge32, Counter32 and Unsigned32, which are mapped
		184	to two different tags: you can distinguish between Counter32 and the
		185	others, but not between Gause32 and Unsigned32, without the ASN.1 schema.
		186
		187	Ugh.
		188
		189	=head2 DECODED BER REPRESENTATION
		190
		191	This module represents every BER value as a 4-element tuple (actually an
		192	array-reference):
		193
		194	[CLASS, TAG, FLAGS, DATA]
		195
		196	For example:
		197
		198	[ASN_UNIVERSAL, ASN_INTEGER, 0, 177] # the integer 177
		199	[ASN_UNIVERSAL, ASN_OCTET_STRING, 0, "john"] # the string "john"
		200	[ASN_UNIVERSAL, ASN_OID, 0, "1.3.6.133"] # some OID
		201	[ASN_UNIVERSAL, ASN_SEQUENCE, 1, [ [ASN_UNIVERSAL... # a sequence
		202
		203	To avoid non-descriptive hardcoded array index numbers, this module
		204	defines symbolic constants to access these members: C<BER_CLASS>,
		205	C<BER_TAG>, C<BER_FLAGS> and C<BER_DATA>.
		206
		207	Also, the first three members are integers with a little caveat: for
		208	performance reasons, these are readonly and shared, so you must not modify
		209	them (increment, assign to them etc.) in any way. You may modify the
		210	I<DATA> member, and you may re-assign the array itself, e.g.:
		211
		212	$ber = ber_decode $binbuf;
		213
		214	# the following is NOT legal:
		215	$ber->[BER_CLASS] = ASN_PRIVATE; # ERROR, CLASS/TAG/FLAGS are READ ONLY(!)
		216
		217	# but all of the following are fine:
		218	$ber->[BER_DATA] = "string";
		219	$ber->[BER_DATA] = [ASN_UNIVERSAL, ASN_INTEGER, 0, 123];
		220	@$ber = (ASN_APPLICATION, SNMP_TIMETICKS, 0, 1000);
		221
		222	I<CLASS> is something like a namespace for I<TAG>s - there is the
		223	C<ASN_UNIVERSAL> namespace which defines tags common to all ASN.1
		224	implementations, the C<ASN_APPLICATION> namespace which defines tags for
		225	specific applications (for example, the SNMP C<Unsigned32> type is in this
		226	namespace), a special-purpose context namespace (C<ASN_CONTEXT>, used e.g.
		227	for C<CHOICE>) and a private namespace (C<ASN_PRIVATE>).
		228
		229	The meaning of the I<TAG> depends on the namespace, and defines a
		230	(partial) interpretation of the data value. For example, SNMP defines
		231	extra tags in the C<ASN_APPLICATION> namespace, and to take full advantage
		232	of these, you need to tell this module how to handle those via profiles.
		233
		234	The most common tags in the C<ASN_UNIVERSAL> namespace are
		235	C<ASN_INTEGER>, C<ASN_BIT_STRING>, C<ASN_NULL>, C<ASN_OCTET_STRING>,
		236	C<ASN_OBJECT_IDENTIFIER>, C<ASN_SEQUENCE>, C<ASN_SET> and
		237	C<ASN_IA5_STRING>.
		238
		239	The most common tags in SNMP's C<ASN_APPLICATION> namespace are
		240	C<SNMP_COUNTER32>, C<SNMP_UNSIGNED32>, C<SNMP_TIMETICKS> and
		241	C<SNMP_COUNTER64>.
		242
		243	The I<FLAGS> value is really just a boolean at this time (but might
		244	get extended) - if it is C<0>, the value is "primitive" and contains
		245	no subvalues, kind of like a non-reference perl scalar. If it is C<1>,
		246	then the value is "constructed" which just means it contains a list of
		247	subvalues which this module will en-/decode as BER tuples themselves.
		248
		249	The I<DATA> value is either a reference to an array of further tuples
		250	(if the value is I<FLAGS>), some decoded representation of the value, if
		251	this module knows how to decode it (e.g. for the integer types above) or
		252	a binary string with the raw octets if this module doesn't know how to
		253	interpret the namespace/tag.
		254
		255	Thus, you can always decode a BER data structure and at worst you get a
		256	string in place of some nice decoded value.
		257
		258	See the SYNOPSIS for an example of such an encoded tuple representation.
		259
		260	=head2 DECODING AND ENCODING
		261
		262	=over
		263
		264	=item $tuple = ber_decode $bindata[, $profile]
		265
		266	Decodes binary BER data in C<$bindata> and returns the resulting BER
		267	tuple. Croaks on any decoding error, so the returned C<$tuple> is always
		268	valid.
		269
		270	How tags are interpreted is defined by the second argument, which must
		271	be a C<Convert::BER::XS::Profile> object. If it is missing, the default
		272	profile will be used (C<$Convert::BER::XS::DEFAULT_PROFILE>).
		273
		274	In addition to rolling your own, this module provides a
		275	C<$Convert::BER::XS::SNMP_PROFILE> that knows about the additional SNMP
		276	types.
		277
		278	Example: decode a BER blob using the default profile - SNMP values will be
		279	decided as raw strings.
		280
		281	$tuple = ber_decode $data;
		282
		283	Example: as above, but use the provided SNMP profile.
		284
		285	$tuple = ber_encode $data, $Convert::BER::XS::SNMP_PROFILE;
		286
		287	=item ($tuple, $bytes) = ber_decode_prefix $bindata[, $profile]
		288
		289	Works like C<ber_decode>, except it doesn't croak when there is data after
		290	the BER data, but instead returns the decoded value and the number of
		291	bytes it decoded.
		292
		293	This is useful when you have BER data at the start of a buffer and other
		294	data after, and you need to find the length.
		295
		296	Also, since BER is self-delimited, this can be used to decode multiple BER
		297	values joined together.
		298
		299	=item $bindata = ber_encode $tuple[, $profile]
		300
		301	Encodes the BER tuple into a BER/DER data structure. AS with
		302	Cyber_decode>, an optional profile can be given.
		303
		304	The encoded data should be both BER and DER ("shortest form") compliant
		305	unless the input says otherwise (e.g. it uses constructed strings).
		306
		307	=back
		308
		309	=head2 HELPER FUNCTIONS
		310
		311	Working with a 4-tuple for every value can be annoying. Or, rather, I<is>
		312	annoying. To reduce this a bit, this module defines a number of helper
		313	functions, both to match BER tuples and to construct BER tuples:
		314
		315	=head3 MATCH HELPERS
		316
		317	These functions accept a BER tuple as first argument and either partially
		318	or fully match it. They often come in two forms, one which exactly matches
		319	a value, and one which only matches the type and returns the value.
		320
		321	They do check whether valid tuples are passed in and croak otherwise. As
		322	a ease-of-use exception, they usually also accept C<undef> instead of a
		323	tuple reference, in which case they silently fail to match.
		324
		325	=over
		326
		327	=item $bool = ber_is $tuple, $class, $tag, $flags, $data
		328
		329	This takes a BER C<$tuple> and matches its elements against the provided
		330	values, all of which are optional - values that are either missing or
		331	C<undef> will be ignored, the others will be matched exactly (e.g. as if
		332	you used C<==> or C<eq> (for C<$data>)).
		333
		334	Some examples:
		335
		336	ber_is $tuple, ASN_UNIVERSAL, ASN_SEQUENCE, 1
		337	orf die "tuple is not an ASN SEQUENCE";
		338
		339	ber_is $tuple, ASN_UNIVERSAL, ASN_NULL
		340	or die "tuple is not an ASN NULL value";
		341
		342	ber_is $tuple, ASN_UNIVERSAL, ASN_INTEGER, 0, 50
		343	or die "BER integer must be 50";
		344
		345	=item $seq = ber_is_seq $tuple
		346
		347	Returns the sequence members (the array of subvalues) if the C<$tuple> is
		348	an ASN SEQUENCE, i.e. the C<BER_DATA> member. If the C<$tuple> is not a
		349	sequence it returns C<undef>. For example, SNMP version 1/2c/3 packets all
		350	consist of an outer SEQUENCE value:
		351
		352	my $ber = ber_decode $snmp_data;
		353
		354	my $snmp = ber_is_seq $ber
		355	or die "SNMP packet invalid: does not start with SEQUENCE";
		356
		357	# now we know $snmp is a sequence, so decode the SNMP version
		358
		359	my $version = ber_is_int $snmp->[0]
		360	or die "SNMP packet invalid: does not start with version number";
		361
		362	=item $bool = ber_is_int $tuple, $int
		363
		364	Returns a true value if the C<$tuple> represents an ASN INTEGER with
		365	the value C<$int>.
		366
		367	=item $int = ber_is_int $tuple
		368
		369	Returns true (and extracts the integer value) if the C<$tuple> is an
		370	C<ASN_INTEGER>. For C<0>, this function returns a special value that is 0
		371	but true.
		372
		373	=item $bool = ber_is_oid $tuple, $oid_string
		374
		375	Returns true if the C<$tuple> represents an ASN_OBJECT_IDENTIFIER
		376	that exactly matches C<$oid_string>. Example:
		377
		378	ber_is_oid $tuple, "1.3.6.1.4"
		379	or die "oid must be 1.3.6.1.4";
		380
		381	=item $oid = ber_is_oid $tuple
		382
		383	Returns true (and extracts the OID string) if the C<$tuple> is an ASN
		384	OBJECT IDENTIFIER. Otherwise, it returns C<undef>.
		385
		386	=back
		387
		388	=head3 CONSTRUCTION HELPERS
		389
		390	=over
		391
		392	=item $tuple = ber_int $value
		393
		394	Constructs a new C<ASN_INTEGER> tuple.
		395
		396	=back
		397
		398	=head2 RELATIONSHIP TO L<Convert::BER> and L<Convert::ASN1>
		399
		400	This module is I<not> the XS version of L<Convert::BER>, but a different
		401	take at doing the same thing. I imagine this module would be a good base
		402	for speeding up either of these, or write a similar module, or write your
		403	own LDAP or SNMP module for example.
44		404
45	=cut	405	=cut
46		406
47	package Convert::BER::XS;	407	package Convert::BER::XS;
48		408
49	use common::sense;	409	use common::sense;
50		410
51	use XSLoader ();	411	use XSLoader ();
52	use Exporter qw(import);	412	use Exporter qw(import);
53		413
		414	our $VERSION;
		415
		416	BEGIN {
54	our $VERSION = '0.0';	417	$VERSION = '1.0';
55
56	XSLoader::load __PACKAGE__, $VERSION;	418	XSLoader::load __PACKAGE__, $VERSION;
		419	}
57		420
58	our %EXPORT_TAGS = (	421	our %EXPORT_TAGS = (
59	all => [qw(	422	const_index => [qw(
60	ber_decode	423	BER_CLASS BER_TAG BER_FLAGS BER_DATA
		424	)],
		425	const_asn_class => [qw(
		426	ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE
		427	)],
		428	const_asn_tag => [qw(
		429	ASN_BOOLEAN ASN_INTEGER ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OID ASN_OBJECT_IDENTIFIER
		430	ASN_OBJECT_DESCRIPTOR ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED
		431	ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING
		432	ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING
		433	ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING
		434	ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING
		435	)],
		436	const_ber_type => [qw(
		437	BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT
		438	BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL
		439	BER_TYPE_IPADDRESS BER_TYPE_CROAK
		440	)],
		441	const_snmp => [qw(
		442	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_GAUGE32 SNMP_UNSIGNED32
		443	SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
		444	)],
		445	decode => [qw(
		446	ber_decode ber_decode_prefix
61	ber_is ber_is_seq ber_is_i32 ber_is_oid	447	ber_is ber_is_seq ber_is_int ber_is_oid
62	BER_CLASS BER_TAG BER_CONSTRUCTED BER_DATA	448	ber_dump
63	ASN_BOOLEAN ASN_INTEGER32 ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER ASN_TAG_BER ASN_TAG_MASK	449	)],
64	ASN_CONSTRUCTED ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE ASN_CLASS_MASK ASN_CLASS_SHIFT	450	encode => [qw(
65	ASN_SEQUENCE ASN_IPADDRESS ASN_COUNTER32 ASN_UNSIGNED32 ASN_TIMETICKS ASN_OPAQUE ASN_COUNTER64	451	ber_encode
		452	ber_int
66	)],	453	)],
67	);	454	);
68		455
69	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;	456	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;
70		457
71	1;	458	$EXPORT_TAGS{all} = \@EXPORT_OK;
		459	$EXPORT_TAGS{const_asn} = [map @{ $EXPORT_TAGS{$_} }, qw(const_asn_class const_asn_tag)];
		460	$EXPORT_TAGS{const} = [map @{ $EXPORT_TAGS{$_} }, qw(const_index const_asn)];
		461
		462	our $DEFAULT_PROFILE = new Convert::BER::XS::Profile;
		463
		464	$DEFAULT_PROFILE->_set_default;
		465
		466	# additional SNMP application types
		467	our $SNMP_PROFILE = new Convert::BER::XS::Profile;
		468
		469	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS);
		470	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT);
		471	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT);
		472	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT);
		473	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_IPADDRESS);
		474
		475	=head2 DEBUGGING
		476
		477	To aid debugging, you cna call the C<ber_dump> function to print a "nice"
		478	representation to STDOUT.
		479
		480	=over
		481
		482	=item ber_dump $tuple[, $profile[, $prefix]]
		483
		484	In addition to specifying the BER C<$tuple> to dump, youc an also specify
		485	a C<$profile> and a C<$prefix> string that is printed in front of each line.
		486
		487	If C<$profile> is C<$Convert::BER::XS::SNMP_PROFILE>, then C<ber_dump>
		488	will try to improve its output for SNMP data.
		489
		490	The output usually contains three columns, the "human readable" tag, the
		491	BER type used to decode it, and the data value.
		492
		493	This function is somewhat slow and uses a number of heuristics and tricks,
		494	so it really is only suitable for debug prints.
		495
		496	Example output:
		497
		498	SEQUENCE
		499	\| OCTET_STRING bytes 800063784300454045045400000001
		500	\| OCTET_STRING bytes
		501	\| CONTEXT (7) bytes CONSTRUCTED
		502	\| \| INTEGER int 1058588941
		503	\| \| INTEGER int 0
		504	\| \| INTEGER int 0
		505	\| \| SEQUENCE
		506	\| \| \| SEQUENCE
		507	\| \| \| \| OID oid 1.3.6.1.2.1.1.3.0
		508	\| \| \| \| TIMETICKS int 638085796
		509
		510	=cut
		511
		512	# reverse enum, very slow and ugly hack
		513	sub _re {
		514	my ($export_tag, $value) = @_;
		515
		516	for my $symbol (@{ $EXPORT_TAGS{$export_tag} }) {
		517	$value == eval $symbol
		518	and return $symbol;
		519	}
		520
		521	"($value)"
		522	}
		523
		524	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT);
		525
		526	sub _ber_dump {
		527	my ($ber, $profile, $indent) = @_;
		528
		529	if (my $seq = ber_is_seq $ber) {
		530	printf "%sSEQUENCE\n", $indent;
		531	&_ber_dump ($_, $profile, "$indent\| ")
		532	for @$seq;
		533	} else {
		534	my $asn = $ber->[BER_CLASS] == ASN_UNIVERSAL;
		535
		536	my $class = _re const_asn_class => $ber->[BER_CLASS];
		537	my $tag = $asn ? _re const_asn_tag => $ber->[BER_TAG] : $ber->[BER_TAG];
		538	my $type = _re const_ber_type => $profile->get ($ber->[BER_CLASS], $ber->[BER_TAG]);
		539	my $data = $ber->[BER_DATA];
		540
		541	if ($profile == $SNMP_PROFILE and $ber->[BER_CLASS] == ASN_APPLICATION) {
		542	$tag = _re const_snmp => $ber->[BER_TAG];
		543	} elsif (!$asn) {
		544	$tag = "$class ($tag)";
		545	}
		546
		547	$class =~ s/^ASN_//;
		548	$tag =~ s/^(ASN_\|SNMP_)//;
		549	$type =~ s/^BER_TYPE_//;
		550
		551	if ($ber->[BER_FLAGS]) {
		552	printf "$indent%-16.16s %-6.6s CONSTRUCTED\n", $tag, lc $type;
		553	&_ber_dump ($_, $profile, "$indent\| ")
		554	for @$data;
		555	} else {
		556	if ($data =~ y/\x20-\x7e//c > 10 or $data =~ /\x00./s) {
		557	# assume binary
		558	$data = unpack "H*", $data;
		559	substr $data, 40, 1e9, "..." if 40 < length $data;
		560	} else {
		561	$data =~ s/[^\x20-\x7e]/./g;
		562	$data = "\"$data\"" if $type =~ /string/i;
		563	substr $data, 40, 1e9, "..." if 40 < length $data;
		564	}
		565
		566	printf "$indent%-16.16s %-6.6s %s\n", $tag, lc $type, $data;
		567	}
		568	}
		569	}
		570
		571	sub ber_dump($;$$) {
		572	_ber_dump $_[0], $_[1] \|\| $DEFAULT_PROFILE, $_[2];
		573	}
		574
		575	=head1 PROFILES
		576
		577	While any BER data can be correctly encoded and decoded out of the box, it
		578	can be inconvenient to have to manually decode some values into a "better"
		579	format: for instance, SNMP TimeTicks values are decoded into the raw octet
		580	strings of their BER representation, which is quite hard to decode. With
		581	profiles, you can change which class/tag combinations map to which decoder
		582	function inside C<ber_decode> (and of course also which encoder functions
		583	are used in C<ber_encode>).
		584
		585	This works by mapping specific class/tag combinations to an internal "ber
		586	type".
		587
		588	The default profile supports the standard ASN.1 types, but no
		589	application-specific ones. This means that class/tag combinations not in
		590	the base set of ASN.1 are decoded into their raw octet strings.
		591
		592	C<Convert::BER::XS> defines two profile variables you can use out of the box:
		593
		594	=over
		595
		596	=item C<$Convert::BER::XS::DEFAULT_PROFILE>
		597
		598	This is the default profile, i.e. the profile that is used when no
		599	profile is specified for de-/encoding.
		600
		601	You can modify it, but remember that this modifies the defaults for all
		602	callers that rely on the default profile.
		603
		604	=item C<$Convert::BER::XS::SNMP_PROFILE>
		605
		606	A profile with mappings for SNMP-specific application tags added. This is
		607	useful when de-/encoding SNMP data.
		608
		609	Example:
		610
		611	$ber = ber_decode $data, $Convert::BER::XS::SNMP_PROFILE;
		612
		613	=back
		614
		615	=head2 The Convert::BER::XS::Profile class
		616
		617	=over
		618
		619	=item $profile = new Convert::BER::XS::Profile
		620
		621	Create a new profile. The profile will be identical to the default
		622	profile.
		623
		624	=item $profile->set ($class, $tag, $type)
		625
		626	Sets the mapping for the given C<$class>/C<$tag> combination to C<$type>,
		627	which must be one of the C<BER_TYPE_*> constants.
		628
		629	Note that currently, the mapping is stored in a flat array, so large
		630	values of C<$tag> will consume large amounts of memory.
		631
		632	Example:
		633
		634	$profile = new Convert::BER::XS::Profile;
		635	$profile->set (ASN_APPLICATION, SNMP_COUNTER32, BER_TYPE_INT);
		636	$ber = ber_decode $data, $profile;
		637
		638	=item $type = $profile->get ($class, $tag)
		639
		640	Returns the BER type mapped to the given C<$class>/C<$tag> combination.
		641
		642	=back
		643
		644	=head2 BER TYPES
		645
		646	This lists the predefined BER types - you can map any C<CLASS>/C<TAG>
		647	combination to any C<BER_TYPE_*>.
		648
		649	=over
		650
		651	=item C<BER_TYPE_BYTES>
		652
		653	The raw octets of the value. This is the default type for unknown tags and
		654	de-/encodes the value as if it were an octet string, i.e. by copying the
		655	raw bytes.
		656
		657	=item C<BER_TYPE_UTF8>
		658
		659	Like C<BER_TYPE_BYTES>, but decodes the value as if it were a UTF-8 string
		660	(without validation!) and encodes a perl unicode string into a UTF-8 BER
		661	string.
		662
		663	=item C<BER_TYPE_UCS2>
		664
		665	Similar to C<BER_TYPE_UTF8>, but treats the BER value as UCS-2 encoded
		666	string.
		667
		668	=item C<BER_TYPE_UCS4>
		669
		670	Similar to C<BER_TYPE_UTF8>, but treats the BER value as UCS-4 encoded
		671	string.
		672
		673	=item C<BER_TYPE_INT>
		674
		675	Encodes and decodes a BER integer value to a perl integer scalar. This
		676	should correctly handle 64 bit signed and unsigned values.
		677
		678	=item C<BER_TYPE_OID>
		679
		680	Encodes and decodes an OBJECT IDENTIFIER into dotted form without leading
		681	dot, e.g. C<1.3.6.1.213>.
		682
		683	=item C<BER_TYPE_RELOID>
		684
		685	Same as C<BER_TYPE_OID> but uses relative object identifier
		686	encoding: ASN.1 has this hack of encoding the first two OID components
		687	into a single integer in a weird attempt to save an insignificant amount
		688	of space in an otherwise wasteful encoding, and relative OIDs are
		689	basically OIDs without this hack. The practical difference is that the
		690	second component of an OID can only have the values 1..40, while relative
		691	OIDs do not have this restriction.
		692
		693	=item C<BER_TYPE_NULL>
		694
		695	Decodes an C<ASN_NULL> value into C<undef>, and always encodes a
		696	C<ASN_NULL> type, regardless of the perl value.
		697
		698	=item C<BER_TYPE_BOOL>
		699
		700	Decodes an C<ASN_BOOLEAN> value into C<0> or C<1>, and encodes a perl
		701	boolean value into an C<ASN_BOOLEAN>.
		702
		703	=item C<BER_TYPE_REAL>
		704
		705	Decodes/encodes a BER real value. NOT IMPLEMENTED.
		706
		707	=item C<BER_TYPE_IPADDRESS>
		708
		709	Decodes/encodes a four byte string into an IPv4 dotted-quad address string
		710	in Perl. Given the obsolete nature of this type, this is a low-effort
		711	implementation that simply uses C<sprintf> and C<sscanf>-style conversion,
		712	so it won't handle all string forms supported by C<inet_aton> for example.
		713
		714	=item C<BER_TYPE_CROAK>
		715
		716	Always croaks when encountered during encoding or decoding - the
		717	default behaviour when encountering an unknown type is to treat it as
		718	C<BER_TYPE_BYTES>. When you don't want that but instead prefer a hard
		719	error for some types, then C<BER_TYPE_CROAK> is for you.
		720
		721	=back
		722
		723	=head2 Example Profile
		724
		725	The following creates a profile suitable for SNMP - it's exactly identical
		726	to the C<$Convert::BER::XS::SNMP_PROFILE> profile.
		727
		728	our $SNMP_PROFILE = new Convert::BER::XS::Profile;
		729
		730	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS);
		731	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT);
		732	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT);
		733	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT);
		734	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_IPADDRESS);
		735	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT);
		736
		737	=head2 LIMITATIONS/NOTES
		738
		739	This module can only en-/decode 64 bit signed and unsigned integers, and
		740	only when your perl supports those.
		741
		742	This module does not generally care about ranges, i.e. it will happily
		743	de-/encode 64 bit integers into an C<ASN_INTEGER> value, or a negative
		744	number into an C<SNMP_COUNTER64>.
		745
		746	OBJECT IDENTIFIEERs cannot have unlimited length, although the limit is
		747	much larger than e.g. the one imposed by SNMP or other protocols,a nd is
		748	about 4kB.
		749
		750	Indefinite length encoding is not supported.
		751
		752	Constructed strings are decoded just fine, but there should be a way to
		753	join them for convenience.
		754
		755	REAL values are not supported and will currently croak.
		756
		757	The encoder and decoder tend to accept more formats than should be
		758	strictly supported.
		759
		760	This module has undergone little to no testing so far.
		761
		762	=head2 ITHREADS SUPPORT
		763
		764	This module is unlikely to work when the (officially discouraged) ithreads
		765	are in use.
72		766
73	=head1 AUTHOR	767	=head1 AUTHOR
74		768
75	Marc Lehmann <schmorp@schmorp.de>	769	Marc Lehmann <schmorp@schmorp.de>
76	http://software.schmorp.de/pkg/Convert-BER-XS	770	http://software.schmorp.de/pkg/Convert-BER-XS
77		771
78	=cut	772	=cut
79		773
		774	1;
		775

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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 1.38 by root, Sun Apr 21 00:39:26 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 1.38 by root, Sun Apr 21 00:39:26 2019 UTC