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

Comparing Convert-BER-XS/XS.pm (file contents):
Revision 1.5 by root, Fri Apr 19 19:46:41 2019 UTC vs.
Revision 1.63 by root, Wed Mar 3 05:30:23 2021 UTC

…		…
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	# decode a binary BER data structure using the SNMP profile
		10	my $ber = ber_decode $buf, $Convert::BER::XS::SNMP_PROFILE
10	or die "unable to decode SNMP v1/v2c Message";	11	or die "unable to decode SNMP message";
11		12
12	# the above results in a data structure consisting of (class, tag,	13	# The above results in a data structure consisting of
13	# constructed, data) tuples. here is such a message, SNMPv1 trap	14	# (class, tag, flags, data)
		15	# tuples. Below is such a message, an SNMPv1 trap
14	# with a cisoc mac change notification	16	# with a Cisco mac change notification.
		17	# (Did you know that Cisco is in the news almost
		18	# every week because of some backdoor password
		19	# or other extremely stupid security bug?)
15		20
16	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1,	21	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1,
17	[	22	[
18	[ ASN_UNIVERSAL, ASN_INTEGER32, 0, 0 ], # snmp version 1	23	[ ASN_UNIVERSAL, ASN_INTEGER, 0, 0 ], # snmp version 1
19	[ ASN_UNIVERSAL, 4, 0, "public" ], # community	24	[ ASN_UNIVERSAL, 4, 0, "public" ], # community
20	[ ASN_CONTEXT, 4, 1, # CHOICE, constructed	25	[ ASN_CONTEXT, 4, 1, # CHOICE, constructed - trap PDU
21	[	26	[
22	[ ASN_UNIVERSAL, ASN_OBJECT_IDENTIFIER, 0, "1.3.6.1.4.1.9.9.215.2" ], # enterprise oid	27	[ ASN_UNIVERSAL, ASN_OBJECT_IDENTIFIER, 0, "1.3.6.1.4.1.9.9.215.2" ], # enterprise oid
23	[ ASN_APPLICATION, 0, 0, "\x0a\x00\x00\x01" ], # SNMP IpAddress, 10.0.0.1	28	[ ASN_APPLICATION, SNMP_IPADDRESS, 0, "10.0.0.1" ], # SNMP IpAddress
24	[ ASN_UNIVERSAL, ASN_INTEGER32, 0, 6 ], # generic trap	29	[ ASN_UNIVERSAL, ASN_INTEGER, 0, 6 ], # generic trap
25	[ ASN_UNIVERSAL, ASN_INTEGER32, 0, 1 ], # specific trap	30	[ ASN_UNIVERSAL, ASN_INTEGER, 0, 1 ], # specific trap
26	[ ASN_APPLICATION, ASN_TIMETICKS, 0, 1817903850 ], # SNMP TimeTicks	31	[ ASN_APPLICATION, SNMP_TIMETICKS, 0, 1817903850 ], # SNMP TimeTicks
27	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # the varbindlist	32	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # the varbindlist
28	[	33	[
29	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # a single varbind, "key value" pair	34	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # a single varbind, "key value" pair
30	[	35	[
31	[ ASN_UNIVERSAL, ASN_OBJECT_IDENTIFIER, 0, "1.3.6.1.4.1.9.9.215.1.1.8.1.2.1" ], # the oid	36	[ ASN_UNIVERSAL, ASN_OBJECT_IDENTIFIER, 0, "1.3.6.1.4.1.9.9.215.1.1.8.1.2.1" ],
32	[ ASN_UNIVERSAL, ASN_OCTET_STRING, 0, "...data..." # the value	37	[ ASN_UNIVERSAL, ASN_OCTET_STRING, 0, "...data..." # the value
33	]	38	]
34	]	39	]
35	],	40	],
36	...	41	...
37		42
		43	# let's dump the above structure, for debugging
		44	ber_dump $ber, $Convert::BER::XS::SNMP_PROFILE;
		45
38	# let's decode it a bit with some helper functions	46	# let's decode it a bit with some helper functions.
39		47	# first check whether it starts with a sequence
40	my $msg = ber_is_seq $ber	48	my $msg = ber_is_seq $ber
41	or die "SNMP message does not start with a sequence";	49	or die "SNMP message does not start with a sequence";
42		50
		51	# then check if its some kind of integer
43	ber_is $msg->[0], ASN_UNIVERSAL, ASN_INTEGER32, 0	52	ber_is $msg->[0], ASN_UNIVERSAL, ASN_INTEGER, 0
44	or die "SNMP message does not start with snmp version\n";	53	or die "SNMP message does not start with snmp version";
45		54
46	# message is SNMP v1 or v2c?	55	# message is SNMP v1 or v2c?
47	if ($msg->[0][BER_DATA] == 0 \|\| $msg->[0][BER_DATA] == 1) {	56	if ($msg->[0][BER_DATA] == 0 \|\| $msg->[0][BER_DATA] == 1) {
48		57
49	# message is v1 trap?	58	# message is v1 trap?
…		…
51	my $trap = $msg->[2][BER_DATA];	60	my $trap = $msg->[2][BER_DATA];
52		61
53	# check whether trap is a cisco mac notification mac changed message	62	# check whether trap is a cisco mac notification mac changed message
54	if (	63	if (
55	(ber_is_oid $trap->[0], "1.3.6.1.4.1.9.9.215.2") # cmnInterfaceObjects	64	(ber_is_oid $trap->[0], "1.3.6.1.4.1.9.9.215.2") # cmnInterfaceObjects
56	and (ber_is_i32 $trap->[2], 6)	65	and (ber_is_int $trap->[2], 6)
57	and (ber_is_i32 $trap->[3], 1) # mac changed msg	66	and (ber_is_int $trap->[3], 1) # mac changed msg
58	) {	67	) {
59	... and so on	68	... and so on
60		69
61	# finally, let's encode it again and hope it results in the same bit pattern	70	# finally, let's encode it again and hope it results in the same bit pattern
62		71	my $buf = ber_encode $ber, $Convert::BER::XS::SNMP_PROFILE;
63	my $buf = ber_encode $ber;
64		72
65	=head1 DESCRIPTION	73	=head1 DESCRIPTION
66		74
67	This module implements a I<very> low level BER/DER en-/decoder.	75	This module implements a I<very> low level BER/DER en-/decoder.
68		76
69	If is tuned for low memory and high speed, while still maintaining some	77	It is tuned for low memory and high speed, while still maintaining some
70	level of user-friendlyness.	78	level of user-friendlyness.
71		79
72	Currently, not much is documented, as this is an initial release to	80	=head2 EXPORT TAGS AND CONSTANTS
73	reserve CPAN namespace, stay tuned for a few days.	81
		82	By default this module doesn't export any symbols, but if you don't want
		83	to break your keyboard, editor or eyesight with extremely long names, I
		84	recommend importing the C<:all> tag. Still, you can selectively import
		85	things.
		86
		87	=over
		88
		89	=item C<:all>
		90
		91	All of the below. Really. Recommended for at least first steps, or if you
		92	don't care about a few kilobytes of wasted memory (and namespace).
		93
		94	=item C<:const>
		95
		96	All of the strictly ASN.1-related constants defined by this module, the
		97	same as C<:const_asn :const_index>. Notably, this does not contain
		98	C<:const_ber_type> and C<:const_snmp>.
		99
		100	A good set to get everything you need to decode and match BER data would be
		101	C<:decode :const>.
		102
		103	=item C<:const_index>
		104
		105	The BER tuple array index constants:
		106
		107	BER_CLASS BER_TAG BER_FLAGS BER_DATA
		108
		109	=item C<:const_asn>
		110
		111	ASN class values (these are C<0>, C<1>, C<2> and C<3>, respectively -
		112	exactly the two topmost bits from the identifier octet shifted 6 bits to
		113	the right):
		114
		115	ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE
		116
		117	ASN tag values (some of which are aliases, such as C<ASN_OID>). Their
		118	numerical value corresponds exactly to the numbers used in BER/X.690.
		119
		120	ASN_BOOLEAN ASN_INTEGER ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OID
		121	ASN_OBJECT_IDENTIFIER ASN_OBJECT_DESCRIPTOR ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED
		122	ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING
		123	ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING
		124	ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING
		125	ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING
		126
		127	=item C<:const_ber_type>
		128
		129	The BER type constants, explained in the PROFILES section.
		130
		131	BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT
		132	BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL
		133	BER_TYPE_IPADDRESS BER_TYPE_CROAK
		134
		135	=item C<:const_snmp>
		136
		137	Constants only relevant to SNMP. These are the tag values used by SNMP in
		138	the C<ASN_APPLICATION> namespace and have the exact numerical value as in
		139	BER/RFC 2578.
		140
		141	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_GAUGE32
		142	SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
		143
		144	=item C<:decode>
		145
		146	C<ber_decode> and the match helper functions:
		147
		148	ber_decode ber-decode_prefix
		149	ber_is ber_is_seq ber_is_int ber_is_oid
		150	ber_dump
		151
		152	=item C<:encode>
		153
		154	C<ber_encode> and the construction helper functions:
		155
		156	ber_encode
		157	ber_int
		158
		159	=back
74		160
75	=head2 ASN.1/BER/DER/... BASICS	161	=head2 ASN.1/BER/DER/... BASICS
76		162
77	ASN.1 is a strange language that can be sed to describe protocols and	163	ASN.1 is a strange language that can be used to describe protocols and
78	data structures. It supports various mappings to JSON, XML, but most	164	data structures. It supports various mappings to JSON, XML, but most
79	importantly, to a various binary encodings such as BER, that is the topic	165	importantly, to a various binary encodings such as BER, that is the topic
80	of this module, and is used in SNMP or LDAP for example.	166	of this module, and is used in SNMP, LDAP or X.509 for example.
81		167
82	While ASN.1 defines a schema that is useful to interpret encoded data,	168	While ASN.1 defines a schema that is useful to interpret encoded data,
83	the BER encoding is actually somehat self-describing: you might not know	169	the BER encoding is actually somewhat self-describing: you might not know
84	whether something is a string or a number or a sequence or something else,	170	whether something is a string or a number or a sequence or something else,
85	but you can nevertheless decode the overall structure, even if you end up	171	but you can nevertheless decode the overall structure, even if you end up
86	with just a binary blob for the actual value.	172	with just a binary blob for the actual value.
87		173
88	This works because BER values are tagged with a type and a namespace,	174	This works because BER values are tagged with a type and a namespace,
89	and also have a flag that says whther a value consists of subvalues (is	175	and also have a flag that says whether a value consists of subvalues (is
90	"constructed") or not (is "primitive").	176	"constructed") or not (is "primitive").
91		177
92	Tags are simple integers, and ASN.1 defines a somewhat weird assortment of	178	Tags are simple integers, and ASN.1 defines a somewhat weird assortment
93	those - for example, you have 32 bit signed integers and 16(!) different	179	of those - for example, you have one integer but 16(!) different
94	string types, but there is no unsigned32 type for example. Different	180	string types, but there is no Unsigned32 type for example. Different
95	applications work around this in different ways, for example, SNMP defines	181	applications work around this in different ways, for example, SNMP defines
96	application-specific Gauge32, Counter32 and Unsigned32, which are mapped	182	application-specific Gauge32, Counter32 and Unsigned32, which are mapped
97	to two different tags: you can distinguish between Counter32 and the	183	to two different tags: you can distinguish between Counter32 and the
98	others, but not between Gause32 and Unsigned32, without the ASN.1 schema.	184	others, but not between Gause32 and Unsigned32, without the ASN.1 schema.
99		185
…		…
102	=head2 DECODED BER REPRESENTATION	188	=head2 DECODED BER REPRESENTATION
103		189
104	This module represents every BER value as a 4-element tuple (actually an	190	This module represents every BER value as a 4-element tuple (actually an
105	array-reference):	191	array-reference):
106		192
107	[CLASS, TAG, CONSTRUCTED, DATA]	193	[CLASS, TAG, FLAGS, DATA]
		194
		195	For example:
		196
		197	[ASN_UNIVERSAL, ASN_INTEGER, 0, 177] # the integer 177
		198	[ASN_UNIVERSAL, ASN_OCTET_STRING, 0, "john"] # the string "john"
		199	[ASN_UNIVERSAL, ASN_OID, 0, "1.3.6.133"] # some OID
		200	[ASN_UNIVERSAL, ASN_SEQUENCE, 1, [ [ASN_UNIVERSAL... # a sequence
		201
		202	To avoid non-descriptive hardcoded array index numbers, this module
		203	defines symbolic constants to access these members: C<BER_CLASS>,
		204	C<BER_TAG>, C<BER_FLAGS> and C<BER_DATA>.
		205
		206	Also, the first three members are integers with a little caveat: for
		207	performance reasons, these are readonly and shared, so you must not modify
		208	them (increment, assign to them etc.) in any way. You may modify the
		209	I<DATA> member, and you may re-assign the array itself, e.g.:
		210
		211	$ber = ber_decode $binbuf;
		212
		213	# the following is NOT legal:
		214	$ber->[BER_CLASS] = ASN_PRIVATE; # ERROR, CLASS/TAG/FLAGS are READ ONLY(!)
		215
		216	# but all of the following are fine:
		217	$ber->[BER_DATA] = "string";
		218	$ber->[BER_DATA] = [ASN_UNIVERSAL, ASN_INTEGER, 0, 123];
		219	@$ber = (ASN_APPLICATION, SNMP_TIMETICKS, 0, 1000);
108		220
109	I<CLASS> is something like a namespace for I<TAG>s - there is the	221	I<CLASS> is something like a namespace for I<TAG>s - there is the
110	C<ASN_UNIVERSAL> namespace which defines tags common to all ASN.1	222	C<ASN_UNIVERSAL> namespace which defines tags common to all ASN.1
111	implementations, the C<ASN_APPLICATION> namespace which defines tags for	223	implementations, the C<ASN_APPLICATION> namespace which defines tags for
112	specific applications (for example, the SNMP C<Unsigned32> type is in this	224	specific applications (for example, the SNMP C<Unsigned32> type is in this
113	namespace), a special-purpose context namespace (C<ASN_CONTEXT>, used e.g.	225	namespace), a special-purpose context namespace (C<ASN_CONTEXT>, used e.g.
114	for C<CHOICE>) and a private namespace (C<ASN_PRIVATE>).	226	for C<CHOICE>) and a private namespace (C<ASN_PRIVATE>).
115		227
116	The meaning of the I<TAG> depends on the namespace, and defines a	228	The meaning of the I<TAG> depends on the namespace, and defines a
117	(partial) interpretation of the data value. For example, right now, SNMP	229	(partial) interpretation of the data value. For example, SNMP defines
118	application namespace knowledge ix hardcoded into this module, so it	230	extra tags in the C<ASN_APPLICATION> namespace, and to take full advantage
119	knows that SNMP C<Unsigned32> values need to be decoded into actual perl	231	of these, you need to tell this module how to handle those via profiles.
120	integers.
121		232
122	The most common tags in the C<ASN_UNIVERSAL> namespace are	233	The most common tags in the C<ASN_UNIVERSAL> namespace are
123	C<ASN_INTEGER32>, C<ASN_BIT_STRING>, C<ASN_NULL>, C<ASN_OCTET_STRING>,	234	C<ASN_INTEGER>, C<ASN_BIT_STRING>, C<ASN_NULL>, C<ASN_OCTET_STRING>,
124	C<ASN_OBJECT_IDENTIFIER>, C<ASN_SEQUENCE>, C<ASN_SET> and	235	C<ASN_OBJECT_IDENTIFIER>, C<ASN_SEQUENCE>, C<ASN_SET> and
125	C<ASN_IA5_STRING>.	236	C<ASN_IA5_STRING>.
126		237
127	The most common tags in SNMP's C<ASN_APPLICATION> namespace	238	The most common tags in SNMP's C<ASN_APPLICATION> namespace are
128	are C<SNMP_IPADDRESS>, C<SNMP_COUNTER32>, C<SNMP_UNSIGNED32>,	239	C<SNMP_COUNTER32>, C<SNMP_UNSIGNED32>, C<SNMP_TIMETICKS> and
129	C<SNMP_TIMETICKS>, C<SNMP_OPAQUE> and C<SNMP_COUNTER64>.	240	C<SNMP_COUNTER64>.
130		241
131	The I<CONSTRUCTED> flag is really just a boolean - if it is false, the	242	The I<FLAGS> value is really just a boolean at this time (but might
132	the value is "primitive" and contains no subvalues, kind of like a	243	get extended) - if it is C<0>, the value is "primitive" and contains
133	non-reference perl scalar. IF it is true, then the value is "constructed"	244	no subvalues, kind of like a non-reference perl scalar. If it is C<1>,
134	which just means it contains a list of subvalues which this module will	245	then the value is "constructed" which just means it contains a list of
135	en-/decode as BER tuples themselves.	246	subvalues which this module will en-/decode as BER tuples themselves.
136		247
137	The I<DATA> value is either a reference to an array of further tuples (if	248	The I<DATA> value is either a reference to an array of further tuples
138	the value is I<CONSTRUCTED>), some decoded representation of the value,	249	(if the value is I<FLAGS>), some decoded representation of the value, if
139	if this module knows how to decode it (e.g. for the integer types above)	250	this module knows how to decode it (e.g. for the integer types above) or
140	or a binary string with the raw octets if this module doesn't know how to	251	a binary string with the raw octets if this module doesn't know how to
141	interpret the namespace/tag.	252	interpret the namespace/tag.
142		253
143	Thus, you can always decode a BER data structure and at worst you get a	254	Thus, you can always decode a BER data structure and at worst you get a
144	string in place of some nice decoded value.	255	string in place of some nice decoded value.
145		256
146	See the SYNOPSIS for an example of such an encoded tuple representation.	257	See the SYNOPSIS for an example of such an encoded tuple representation.
		258
		259	=head2 DECODING AND ENCODING
		260
		261	=over
		262
		263	=item $tuple = ber_decode $bindata[, $profile]
		264
		265	Decodes binary BER data in C<$bindata> and returns the resulting BER
		266	tuple. Croaks on any decoding error, so the returned C<$tuple> is always
		267	valid.
		268
		269	How tags are interpreted is defined by the second argument, which must
		270	be a C<Convert::BER::XS::Profile> object. If it is missing, the default
		271	profile will be used (C<$Convert::BER::XS::DEFAULT_PROFILE>).
		272
		273	In addition to rolling your own, this module provides a
		274	C<$Convert::BER::XS::SNMP_PROFILE> that knows about the additional SNMP
		275	types.
		276
		277	Example: decode a BER blob using the default profile - SNMP values will be
		278	decided as raw strings.
		279
		280	$tuple = ber_decode $data;
		281
		282	Example: as above, but use the provided SNMP profile.
		283
		284	$tuple = ber_encode $data, $Convert::BER::XS::SNMP_PROFILE;
		285
		286	=item ($tuple, $bytes) = ber_decode_prefix $bindata[, $profile]
		287
		288	Works like C<ber_decode>, except it doesn't croak when there is data after
		289	the BER data, but instead returns the decoded value and the number of
		290	bytes it decoded.
		291
		292	This is useful when you have BER data at the start of a buffer and other
		293	data after, and you need to find the length.
		294
		295	Also, since BER is self-delimited, this can be used to decode multiple BER
		296	values joined together.
		297
		298	=item $bindata = ber_encode $tuple[, $profile]
		299
		300	Encodes the BER tuple into a BER/DER data structure. As with
		301	Cyber_decode>, an optional profile can be given.
		302
		303	The encoded data should be both BER and DER ("shortest form") compliant
		304	unless the input says otherwise (e.g. it uses constructed strings).
		305
		306	=back
		307
		308	=head2 HELPER FUNCTIONS
		309
		310	Working with a 4-tuple for every value can be annoying. Or, rather, I<is>
		311	annoying. To reduce this a bit, this module defines a number of helper
		312	functions, both to match BER tuples and to construct BER tuples:
		313
		314	=head3 MATCH HELPERS
		315
		316	These functions accept a BER tuple as first argument and either partially
		317	or fully match it. They often come in two forms, one which exactly matches
		318	a value, and one which only matches the type and returns the value.
		319
		320	They do check whether valid tuples are passed in and croak otherwise. As
		321	a ease-of-use exception, they usually also accept C<undef> instead of a
		322	tuple reference, in which case they silently fail to match.
		323
		324	=over
		325
		326	=item $bool = ber_is $tuple, $class, $tag, $flags, $data
		327
		328	This takes a BER C<$tuple> and matches its elements against the provided
		329	values, all of which are optional - values that are either missing or
		330	C<undef> will be ignored, the others will be matched exactly (e.g. as if
		331	you used C<==> or C<eq> (for C<$data>)).
		332
		333	Some examples:
		334
		335	ber_is $tuple, ASN_UNIVERSAL, ASN_SEQUENCE, 1
		336	orf die "tuple is not an ASN SEQUENCE";
		337
		338	ber_is $tuple, ASN_UNIVERSAL, ASN_NULL
		339	or die "tuple is not an ASN NULL value";
		340
		341	ber_is $tuple, ASN_UNIVERSAL, ASN_INTEGER, 0, 50
		342	or die "BER integer must be 50";
		343
		344	=item $seq = ber_is_seq $tuple
		345
		346	Returns the sequence members (the array of subvalues) if the C<$tuple> is
		347	an ASN SEQUENCE, i.e. the C<BER_DATA> member. If the C<$tuple> is not a
		348	sequence it returns C<undef>. For example, SNMP version 1/2c/3 packets all
		349	consist of an outer SEQUENCE value:
		350
		351	my $ber = ber_decode $snmp_data;
		352
		353	my $snmp = ber_is_seq $ber
		354	or die "SNMP packet invalid: does not start with SEQUENCE";
		355
		356	# now we know $snmp is a sequence, so decode the SNMP version
		357
		358	my $version = ber_is_int $snmp->[0]
		359	or die "SNMP packet invalid: does not start with version number";
		360
		361	=item $bool = ber_is_int $tuple, $int
		362
		363	Returns a true value if the C<$tuple> represents an ASN INTEGER with
		364	the value C<$int>.
		365
		366	=item $int = ber_is_int $tuple
		367
		368	Returns true (and extracts the integer value) if the C<$tuple> is an
		369	C<ASN_INTEGER>. For C<0>, this function returns a special value that is 0
		370	but true.
		371
		372	=item $bool = ber_is_oid $tuple, $oid_string
		373
		374	Returns true if the C<$tuple> represents an ASN_OBJECT_IDENTIFIER
		375	that exactly matches C<$oid_string>. Example:
		376
		377	ber_is_oid $tuple, "1.3.6.1.4"
		378	or die "oid must be 1.3.6.1.4";
		379
		380	=item $oid = ber_is_oid $tuple
		381
		382	Returns true (and extracts the OID string) if the C<$tuple> is an ASN
		383	OBJECT IDENTIFIER. Otherwise, it returns C<undef>.
		384
		385	=back
		386
		387	=head3 CONSTRUCTION HELPERS
		388
		389	=over
		390
		391	=item $tuple = ber_int $value
		392
		393	Constructs a new C<ASN_INTEGER> tuple.
		394
		395	=back
147		396
148	=head2 RELATIONSHIP TO L<Convert::BER> and L<Convert::ASN1>	397	=head2 RELATIONSHIP TO L<Convert::BER> and L<Convert::ASN1>
149		398
150	This module is I<not> the XS version of L<Convert::BER>, but a different	399	This module is I<not> the XS version of L<Convert::BER>, but a different
151	take at doing the same thing. I imagine this module would be a good base	400	take at doing the same thing. I imagine this module would be a good base
…		…
159	use common::sense;	408	use common::sense;
160		409
161	use XSLoader ();	410	use XSLoader ();
162	use Exporter qw(import);	411	use Exporter qw(import);
163		412
		413	use Carp ();
		414
164	our $VERSION = 0.1;	415	our $VERSION;
165		416
		417	BEGIN {
		418	$VERSION = 1.21;
166	XSLoader::load __PACKAGE__, $VERSION;	419	XSLoader::load __PACKAGE__, $VERSION;
		420	}
167		421
168	our %EXPORT_TAGS = (	422	our %EXPORT_TAGS = (
		423	const_index => [qw(
		424	BER_CLASS BER_TAG BER_FLAGS BER_DATA
		425	)],
		426	const_asn_class => [qw(
		427	ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE
		428	)],
		429	const_asn_tag => [qw(
		430	ASN_BOOLEAN ASN_INTEGER ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OID ASN_OBJECT_IDENTIFIER
		431	ASN_OBJECT_DESCRIPTOR ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED
		432	ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING
		433	ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING
		434	ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING
		435	ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING
		436	)],
		437	const_ber_type => [qw(
		438	BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT
		439	BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL
		440	BER_TYPE_IPADDRESS BER_TYPE_CROAK
		441	)],
169	const => [qw(	442	const_snmp => [qw(
170	BER_CLASS BER_TAG BER_CONSTRUCTED BER_DATA	443	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_GAUGE32 SNMP_UNSIGNED32
171		444	SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
172	ASN_BOOLEAN ASN_INTEGER32 ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER ASN_TAG_BER ASN_TAG_MASK	445	)],
173	ASN_CONSTRUCTED ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE ASN_CLASS_MASK ASN_CLASS_SHIFT	446	decode => [qw(
174	ASN_SEQUENCE	447	ber_decode ber_decode_prefix
175		448	ber_is ber_is_seq ber_is_int ber_is_oid
176	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64	449	ber_dump
177	)],	450	)],
178	encode => [qw(	451	encode => [qw(
179	ber_decode
180	ber_is ber_is_seq ber_is_i32 ber_is_oid
181	)],
182	decode => [qw(
183	ber_encode	452	ber_encode
		453	ber_int
184	)],	454	)],
185	);	455	);
186		456
187	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;	457	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;
188		458
189	$EXPORT_TAGS{all} = \@EXPORT_OK;	459	$EXPORT_TAGS{all} = \@EXPORT_OK;
		460	$EXPORT_TAGS{const_asn} = [map @{ $EXPORT_TAGS{$_} }, qw(const_asn_class const_asn_tag)];
		461	$EXPORT_TAGS{const} = [map @{ $EXPORT_TAGS{$_} }, qw(const_index const_asn)];
190		462
191	1;	463	our $DEFAULT_PROFILE = new Convert::BER::XS::Profile;
192		464
193	=head2 BUGS / SHORTCOMINGs	465	$DEFAULT_PROFILE->_set_default;
194		466
195	This module does have a number of SNMPisms hardcoded, such as the SNMP	467	# additional SNMP application types
196	tags for Unsigned32 and so on. More configurability is needed, and, if	468	our $SNMP_PROFILE = new Convert::BER::XS::Profile;
197	ever implemented, will come in a form similar to how L<JSON::XS> and	469
198	L<CBOR::XS> respresent things, namely with an object-oriented interface.	470	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS);
		471	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT);
		472	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT);
		473	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT);
		474	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT);
		475
		476	# decodes REAL values according to ECMA-63
		477	# this is pretty strict, except it doesn't catch -0.
		478	# I don't have access to ISO 6093 (or BS 6727, or ANSI X.3-42)), so this is all guesswork.
		479	sub _decode_real_decimal {
		480	my ($format, $val) = @_;
		481
		482	$val =~ y/,/./; # probably not in ISO-6093
		483
		484	if ($format == 1) {
		485	$val =~ /^ \ * [+-]? [0-9]+ \z/x
		486	or Carp::croak "BER_TYPE_REAL NR1 value not in NR1 format ($val) (X.690 8.5.8)";
		487	} elsif ($format == 2) {
		488	$val =~ /^ \ * [+-]? (?: [0-9]+\.[0-9]* \| [0-9]*\.[0-9]+ ) \z/x
		489	or Carp::croak "BER_TYPE_REAL NR2 value not in NR2 format ($val) (X.690 8.5.8)";
		490	} elsif ($format == 3) {
		491	$val =~ /^ \ * [+-] (?: [0-9]+\.[0-9]* \| [0-9]*\.[0-9]+ ) [eE] [+-]? [0-9]+ \z/x
		492	or Carp::croak "BER_TYPE_REAL NR3 value not in NR3 format ($val) (X.690 8.5.8)";
		493	} else {
		494	Carp::croak "BER_TYPE_REAL invalid decimal numerical representation format $format";
		495	}
		496
		497	$val
		498	}
		499
		500	# this is a mess, but perl's support for floating point formatting is nearly nonexistant
		501	sub _encode_real_decimal {
		502	my ($val, $nvdig) = @_;
		503
		504	$val = sprintf "%.*G", $nvdig + 1, $val;
		505
		506	if ($val =~ /E/) {
		507	$val =~ s/E(?=[^+-])/E+/;
		508	$val =~ s/E/.E/ if $val !~ /\./;
		509	$val =~ s/^/+/ unless $val =~ /^-/;
		510
		511	return "\x03$val" # NR3
		512	}
		513
		514	$val =~ /\./
		515	? "\x02$val" # NR2
		516	: "\x01$val" # NR1
		517	}
		518
		519	=head2 DEBUGGING
		520
		521	To aid debugging, you can call the C<ber_dump> function to print a "nice"
		522	representation to STDOUT.
		523
		524	=over
		525
		526	=item ber_dump $tuple[, $profile[, $prefix]]
		527
		528	In addition to specifying the BER C<$tuple> to dump, you can also specify
		529	a C<$profile> and a C<$prefix> string that is printed in front of each line.
		530
		531	If C<$profile> is C<$Convert::BER::XS::SNMP_PROFILE>, then C<ber_dump>
		532	will try to improve its output for SNMP data.
		533
		534	The output usually contains three columns, the "human readable" tag, the
		535	BER type used to decode it, and the data value.
		536
		537	This function is somewhat slow and uses a number of heuristics and tricks,
		538	so it really is only suitable for debug prints.
		539
		540	Example output:
		541
		542	SEQUENCE
		543	\| OCTET_STRING bytes 800063784300454045045400000001
		544	\| OCTET_STRING bytes
		545	\| CONTEXT (7) CONSTRUCTED
		546	\| \| INTEGER int 1058588941
		547	\| \| INTEGER int 0
		548	\| \| INTEGER int 0
		549	\| \| SEQUENCE
		550	\| \| \| SEQUENCE
		551	\| \| \| \| OID oid 1.3.6.1.2.1.1.3.0
		552	\| \| \| \| TIMETICKS int 638085796
		553
		554	=back
		555
		556	=cut
		557
		558	# reverse enum, very slow and ugly hack
		559	sub _re {
		560	my ($export_tag, $value) = @_;
		561
		562	for my $symbol (@{ $EXPORT_TAGS{$export_tag} }) {
		563	$value == eval $symbol
		564	and return $symbol;
		565	}
		566
		567	"($value)"
		568	}
		569
		570	sub _ber_dump {
		571	my ($ber, $profile, $indent) = @_;
		572
		573	if (my $seq = ber_is_seq $ber) {
		574	printf "%sSEQUENCE\n", $indent;
		575	&_ber_dump ($_, $profile, "$indent\| ")
		576	for @$seq;
		577	} else {
		578	my $asn = $ber->[BER_CLASS] == ASN_UNIVERSAL;
		579
		580	my $class = _re const_asn_class => $ber->[BER_CLASS];
		581	my $tag = $asn ? _re const_asn_tag => $ber->[BER_TAG] : $ber->[BER_TAG];
		582	my $type = _re const_ber_type => $profile->get ($ber->[BER_CLASS], $ber->[BER_TAG]);
		583	my $data = $ber->[BER_DATA];
		584
		585	if ($profile == $SNMP_PROFILE and $ber->[BER_CLASS] == ASN_APPLICATION) {
		586	$tag = _re const_snmp => $ber->[BER_TAG];
		587	} elsif (!$asn) {
		588	$tag = "$class ($tag)";
		589	}
		590
		591	$class =~ s/^ASN_//;
		592	$tag =~ s/^(ASN_\|SNMP_)//;
		593	$type =~ s/^BER_TYPE_//;
		594
		595	if ($ber->[BER_FLAGS]) {
		596	printf "$indent%-16.16s\n", $tag;
		597	&_ber_dump ($_, $profile, "$indent\| ")
		598	for @$data;
		599	} else {
		600	if ($data =~ y/\x20-\x7e//c / (length $data \|\| 1) > 0.2 or $data =~ /\x00./s) {
		601	# assume binary
		602	$data = unpack "H*", $data;
		603	} else {
		604	$data =~ s/[^\x20-\x7e]/./g;
		605	$data = "\"$data\"" if $tag =~ /string/i \|\| !length $data;
		606	}
		607
		608	substr $data, 40, 1e9, "..." if 40 < length $data;
		609
		610	printf "$indent%-16.16s %-6.6s %s\n", $tag, lc $type, $data;
		611	}
		612	}
		613	}
		614
		615	sub ber_dump($;$$) {
		616	_ber_dump $_[0], $_[1] \|\| $DEFAULT_PROFILE, $_[2];
		617	}
		618
		619	=head1 PROFILES
		620
		621	While any BER data can be correctly encoded and decoded out of the box, it
		622	can be inconvenient to have to manually decode some values into a "better"
		623	format: for instance, SNMP TimeTicks values are decoded into the raw octet
		624	strings of their BER representation, which is quite hard to decode. With
		625	profiles, you can change which class/tag combinations map to which decoder
		626	function inside C<ber_decode> (and of course also which encoder functions
		627	are used in C<ber_encode>).
		628
		629	This works by mapping specific class/tag combinations to an internal "ber
		630	type".
		631
		632	The default profile supports the standard ASN.1 types, but no
		633	application-specific ones. This means that class/tag combinations not in
		634	the base set of ASN.1 are decoded into their raw octet strings.
		635
		636	C<Convert::BER::XS> defines two profile variables you can use out of the box:
		637
		638	=over
		639
		640	=item C<$Convert::BER::XS::DEFAULT_PROFILE>
		641
		642	This is the default profile, i.e. the profile that is used when no
		643	profile is specified for de-/encoding.
		644
		645	You can modify it, but remember that this modifies the defaults for all
		646	callers that rely on the default profile.
		647
		648	=item C<$Convert::BER::XS::SNMP_PROFILE>
		649
		650	A profile with mappings for SNMP-specific application tags added. This is
		651	useful when de-/encoding SNMP data.
		652
		653	The L<Example Profile> section, below, shows how this profile is being
		654	constructed.
		655
		656	Example:
		657
		658	$ber = ber_decode $data, $Convert::BER::XS::SNMP_PROFILE;
		659
		660	=back
		661
		662	=head2 The Convert::BER::XS::Profile class
		663
		664	=over
		665
		666	=item $profile = new Convert::BER::XS::Profile
		667
		668	Create a new profile. The profile will be identical to the default
		669	profile.
		670
		671	=item $profile->set ($class, $tag, $type)
		672
		673	Sets the mapping for the given C<$class>/C<$tag> combination to C<$type>,
		674	which must be one of the C<BER_TYPE_*> constants.
		675
		676	Note that currently, the mapping is stored in a flat array, so large
		677	values of C<$tag> will consume large amounts of memory.
		678
		679	Example:
		680
		681	$profile = new Convert::BER::XS::Profile;
		682	$profile->set (ASN_APPLICATION, SNMP_COUNTER32, BER_TYPE_INT);
		683	$ber = ber_decode $data, $profile;
		684
		685	=item $type = $profile->get ($class, $tag)
		686
		687	Returns the BER type mapped to the given C<$class>/C<$tag> combination.
		688
		689	=back
		690
		691	=head2 BER Types
		692
		693	This lists the predefined BER types. BER types are formatters used
		694	internally to format and encode BER values. You can assign any C<BER_TYPE>
		695	to any C<CLASS>/C<TAG> combination tgo change how that tag is decoded or
		696	encoded.
		697
		698	=over
		699
		700	=item C<BER_TYPE_BYTES>
		701
		702	The raw octets of the value. This is the default type for unknown tags and
		703	de-/encodes the value as if it were an octet string, i.e. by copying the
		704	raw bytes.
		705
		706	=item C<BER_TYPE_UTF8>
		707
		708	Like C<BER_TYPE_BYTES>, but decodes the value as if it were a UTF-8 string
		709	(without validation!) and encodes a perl unicode string into a UTF-8 BER
		710	string.
		711
		712	=item C<BER_TYPE_UCS2>
		713
		714	Similar to C<BER_TYPE_UTF8>, but treats the BER value as UCS-2 encoded
		715	string.
		716
		717	=item C<BER_TYPE_UCS4>
		718
		719	Similar to C<BER_TYPE_UTF8>, but treats the BER value as UCS-4 encoded
		720	string.
		721
		722	=item C<BER_TYPE_INT>
		723
		724	Encodes and decodes a BER integer value to a perl integer scalar. This
		725	should correctly handle 64 bit signed and unsigned values.
		726
		727	=item C<BER_TYPE_OID>
		728
		729	Encodes and decodes an OBJECT IDENTIFIER into dotted form without leading
		730	dot, e.g. C<1.3.6.1.213>.
		731
		732	=item C<BER_TYPE_RELOID>
		733
		734	Same as C<BER_TYPE_OID> but uses relative object identifier
		735	encoding: ASN.1 uses some hack encoding of the first two OID components
		736	into a single integer in a weird attempt to save an insignificant amount
		737	of space in an otherwise wasteful encoding, and relative OIDs are
		738	basically OIDs without this hack. The practical difference is that the
		739	second component of an OID can only have the values 1..40, while relative
		740	OIDs do not have this restriction.
		741
		742	=item C<BER_TYPE_NULL>
		743
		744	Decodes an C<ASN_NULL> value into C<undef>, and always encodes a
		745	C<ASN_NULL> type, regardless of the perl value.
		746
		747	=item C<BER_TYPE_BOOL>
		748
		749	Decodes an C<ASN_BOOLEAN> value into C<0> or C<1>, and encodes a perl
		750	boolean value into an C<ASN_BOOLEAN>.
		751
		752	=item C<BER_TYPE_REAL>
		753
		754	Decodes/encodes a BER real value. NOT IMPLEMENTED.
		755
		756	=item C<BER_TYPE_IPADDRESS>
		757
		758	Decodes/encodes a four byte string into an IPv4 dotted-quad address string
		759	in Perl. Given the obsolete nature of this type, this is a low-effort
		760	implementation that simply uses C<sprintf> and C<sscanf>-style conversion,
		761	so it won't handle all string forms supported by C<inet_aton> for example.
		762
		763	=item C<BER_TYPE_CROAK>
		764
		765	Always croaks when encountered during encoding or decoding - the
		766	default behaviour when encountering an unknown type is to treat it as
		767	C<BER_TYPE_BYTES>. When you don't want that but instead prefer a hard
		768	error for some types, then C<BER_TYPE_CROAK> is for you.
		769
		770	=back
		771
		772	=head2 Example Profile
		773
		774	The following creates a profile suitable for SNMP - it's exactly identical
		775	to the C<$Convert::BER::XS::SNMP_PROFILE> profile.
		776
		777	our $SNMP_PROFILE = new Convert::BER::XS::Profile;
		778
		779	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS);
		780	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT);
		781	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT);
		782	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT);
		783	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_BYTES);
		784	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT);
		785
		786	=head2 LIMITATIONS/NOTES
		787
		788	This module can only en-/decode 64 bit signed and unsigned
		789	integers/tags/lengths, and only when your perl supports those. So no UUID
		790	OIDs for now (unless you map the C<OBJECT IDENTIFIER> tag to something
		791	other than C<BER_TYPE_OID>).
		792
		793	This module does not generally care about ranges, i.e. it will happily
		794	de-/encode 64 bit integers into an C<SNMP_UNSIGNED32> value, or a negative
		795	number into an C<SNMP_COUNTER64>.
		796
		797	OBJECT IDENTIFIEERs cannot have unlimited length, although the limit is
		798	much larger than e.g. the one imposed by SNMP or other protocols, and is
		799	about 4kB.
		800
		801	Constructed strings are decoded just fine, but there should be a way to
		802	join them for convenience.
		803
		804	REAL values will always be encoded in decimal form and ssometimes is
		805	forced into a perl "NV" type, potentially losing precision.
		806
		807	=head2 ITHREADS SUPPORT
		808
		809	This module is unlikely to work in any other than the loading thread when
		810	the (officially discouraged) ithreads are in use.
199		811
200	=head1 AUTHOR	812	=head1 AUTHOR
201		813
202	Marc Lehmann <schmorp@schmorp.de>	814	Marc Lehmann <schmorp@schmorp.de>
203	http://software.schmorp.de/pkg/Convert-BER-XS	815	http://software.schmorp.de/pkg/Convert-BER-XS
204		816
205	=cut	817	=cut
206		818
		819	1;
		820

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Comparing Convert-BER-XS/XS.pm (file contents): Revision 1.5 by root, Fri Apr 19 19:46:41 2019 UTC vs. Revision 1.63 by root, Wed Mar 3 05:30:23 2021 UTC

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Comparing Convert-BER-XS/XS.pm (file contents):
Revision 1.5 by root, Fri Apr 19 19:46:41 2019 UTC vs.
Revision 1.63 by root, Wed Mar 3 05:30:23 2021 UTC