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

Comparing Convert-BER-XS/XS.pm (file contents):
Revision 1.18 by root, Sat Apr 20 13:48:53 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 message";	11	or die "unable to decode SNMP message";
11		12
12	# The above results in a data structure consisting of	13	# The above results in a data structure consisting of
13	# (class, tag, # constructed, data)	14	# (class, tag, flags, data)
14	# tuples. Below is such a message, SNMPv1 trap	15	# tuples. Below is such a message, an SNMPv1 trap
15	# with a Cisco mac change notification.	16	# with a Cisco mac change notification.
16	# Did you know that Cisco is in the news almost	17	# (Did you know that Cisco is in the news almost
17	# every week because # of some backdoor password	18	# every week because of some backdoor password
18	# or other extremely stupid security bug?	19	# or other extremely stupid security bug?)
19		20
20	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1,	21	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1,
21	[	22	[
22	[ ASN_UNIVERSAL, ASN_INTEGER32, 0, 0 ], # snmp version 1	23	[ ASN_UNIVERSAL, ASN_INTEGER, 0, 0 ], # snmp version 1
23	[ ASN_UNIVERSAL, 4, 0, "public" ], # community	24	[ ASN_UNIVERSAL, 4, 0, "public" ], # community
24	[ ASN_CONTEXT, 4, 1, # CHOICE, constructed - trap PDU	25	[ ASN_CONTEXT, 4, 1, # CHOICE, constructed - trap PDU
25	[	26	[
26	[ 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
27	[ 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
28	[ ASN_UNIVERSAL, ASN_INTEGER32, 0, 6 ], # generic trap	29	[ ASN_UNIVERSAL, ASN_INTEGER, 0, 6 ], # generic trap
29	[ ASN_UNIVERSAL, ASN_INTEGER32, 0, 1 ], # specific trap	30	[ ASN_UNIVERSAL, ASN_INTEGER, 0, 1 ], # specific trap
30	[ ASN_APPLICATION, ASN_TIMETICKS, 0, 1817903850 ], # SNMP TimeTicks	31	[ ASN_APPLICATION, SNMP_TIMETICKS, 0, 1817903850 ], # SNMP TimeTicks
31	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # the varbindlist	32	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # the varbindlist
32	[	33	[
33	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # a single varbind, "key value" pair	34	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # a single varbind, "key value" pair
34	[	35	[
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_OBJECT_IDENTIFIER, 0, "1.3.6.1.4.1.9.9.215.1.1.8.1.2.1" ],
…		…
37	]	38	]
38	]	39	]
39	],	40	],
40	...	41	...
41		42
		43	# let's dump the above structure, for debugging
		44	ber_dump $ber, $Convert::BER::XS::SNMP_PROFILE;
		45
42	# let's decode it a bit with some helper functions	46	# let's decode it a bit with some helper functions.
43		47	# first check whether it starts with a sequence
44	my $msg = ber_is_seq $ber	48	my $msg = ber_is_seq $ber
45	or die "SNMP message does not start with a sequence";	49	or die "SNMP message does not start with a sequence";
46		50
		51	# then check if its some kind of integer
47	ber_is $msg->[0], ASN_UNIVERSAL, ASN_INTEGER32, 0	52	ber_is $msg->[0], ASN_UNIVERSAL, ASN_INTEGER, 0
48	or die "SNMP message does not start with snmp version\n";	53	or die "SNMP message does not start with snmp version";
49		54
50	# message is SNMP v1 or v2c?	55	# message is SNMP v1 or v2c?
51	if ($msg->[0][BER_DATA] == 0 \|\| $msg->[0][BER_DATA] == 1) {	56	if ($msg->[0][BER_DATA] == 0 \|\| $msg->[0][BER_DATA] == 1) {
52		57
53	# message is v1 trap?	58	# message is v1 trap?
…		…
55	my $trap = $msg->[2][BER_DATA];	60	my $trap = $msg->[2][BER_DATA];
56		61
57	# check whether trap is a cisco mac notification mac changed message	62	# check whether trap is a cisco mac notification mac changed message
58	if (	63	if (
59	(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
60	and (ber_is_i32 $trap->[2], 6)	65	and (ber_is_int $trap->[2], 6)
61	and (ber_is_i32 $trap->[3], 1) # mac changed msg	66	and (ber_is_int $trap->[3], 1) # mac changed msg
62	) {	67	) {
63	... and so on	68	... and so on
64		69
65	# 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
66		71	my $buf = ber_encode $ber, $Convert::BER::XS::SNMP_PROFILE;
67	my $buf = ber_encode $ber;
68		72
69	=head1 DESCRIPTION	73	=head1 DESCRIPTION
70		74
71	WARNING: Before release 1.0, the API is not considered stable in any way.
72
73	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.
74		76
75	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
76	level of user-friendlyness.	78	level of user-friendlyness.
		79
		80	=head2 EXPORT TAGS AND CONSTANTS
		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
77		160
78	=head2 ASN.1/BER/DER/... BASICS	161	=head2 ASN.1/BER/DER/... BASICS
79		162
80	ASN.1 is a strange language that can be used to describe protocols and	163	ASN.1 is a strange language that can be used to describe protocols and
81	data structures. It supports various mappings to JSON, XML, but most	164	data structures. It supports various mappings to JSON, XML, but most
82	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
83	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.
84		167
85	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,
86	the BER encoding is actually somewhat self-describing: you might not know	169	the BER encoding is actually somewhat self-describing: you might not know
87	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,
88	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
…		…
90		173
91	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,
92	and also have a flag that says whether a value consists of subvalues (is	175	and also have a flag that says whether a value consists of subvalues (is
93	"constructed") or not (is "primitive").	176	"constructed") or not (is "primitive").
94		177
95	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
96	those - for example, you have 32 bit signed integers and 16(!) different	179	of those - for example, you have one integer but 16(!) different
97	string types, but there is no unsigned32 type for example. Different	180	string types, but there is no Unsigned32 type for example. Different
98	applications work around this in different ways, for example, SNMP defines	181	applications work around this in different ways, for example, SNMP defines
99	application-specific Gauge32, Counter32 and Unsigned32, which are mapped	182	application-specific Gauge32, Counter32 and Unsigned32, which are mapped
100	to two different tags: you can distinguish between Counter32 and the	183	to two different tags: you can distinguish between Counter32 and the
101	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.
102		185
…		…
105	=head2 DECODED BER REPRESENTATION	188	=head2 DECODED BER REPRESENTATION
106		189
107	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
108	array-reference):	191	array-reference):
109		192
110	[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
111		201
112	To avoid non-descriptive hardcoded array index numbers, this module	202	To avoid non-descriptive hardcoded array index numbers, this module
113	defines symbolic constants to access these members: C<BER_CLASS>,	203	defines symbolic constants to access these members: C<BER_CLASS>,
114	C<BER_TAG>, C<BER_CONSTRUCTED> and C<BER_DATA>.	204	C<BER_TAG>, C<BER_FLAGS> and C<BER_DATA>.
115		205
116	Also, the first three members are integers with a little caveat: for	206	Also, the first three members are integers with a little caveat: for
117	performance reasons, these are readonly and shared, so you must not modify	207	performance reasons, these are readonly and shared, so you must not modify
118	them (increment, assign to them etc.) in any way. You may modify the	208	them (increment, assign to them etc.) in any way. You may modify the
119	I<DATA> member, and you may re-assign the array itself, e.g.:	209	I<DATA> member, and you may re-assign the array itself, e.g.:
120		210
121	$ber = ber_decode $binbuf;	211	$ber = ber_decode $binbuf;
122		212
123	# the following is NOT legal:	213	# the following is NOT legal:
124	$ber->[BER_CLASS] = ASN_PRIVATE; # ERROR, CLASS/TAG/CONSTRUCTED are READ ONLY(!)	214	$ber->[BER_CLASS] = ASN_PRIVATE; # ERROR, CLASS/TAG/FLAGS are READ ONLY(!)
125		215
126	# but all of the following are fine:	216	# but all of the following are fine:
127	$ber->[BER_DATA] = "string";	217	$ber->[BER_DATA] = "string";
128	$ber->[BER_DATA] = [ASN_UNIVERSAL, ASN_INTEGER32, 0, 123];	218	$ber->[BER_DATA] = [ASN_UNIVERSAL, ASN_INTEGER, 0, 123];
129	@$ber = (ASN_APPLICATION, SNMP_TIMETICKS, 0, 1000);	219	@$ber = (ASN_APPLICATION, SNMP_TIMETICKS, 0, 1000);
130		220
131	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
132	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
133	implementations, the C<ASN_APPLICATION> namespace which defines tags for	223	implementations, the C<ASN_APPLICATION> namespace which defines tags for
134	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
135	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.
136	for C<CHOICE>) and a private namespace (C<ASN_PRIVATE>).	226	for C<CHOICE>) and a private namespace (C<ASN_PRIVATE>).
137		227
138	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
139	(partial) interpretation of the data value. For example, right now, SNMP	229	(partial) interpretation of the data value. For example, SNMP defines
140	application namespace knowledge ix hardcoded into this module, so it	230	extra tags in the C<ASN_APPLICATION> namespace, and to take full advantage
141	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.
142	integers.
143		232
144	The most common tags in the C<ASN_UNIVERSAL> namespace are	233	The most common tags in the C<ASN_UNIVERSAL> namespace are
145	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>,
146	C<ASN_OBJECT_IDENTIFIER>, C<ASN_SEQUENCE>, C<ASN_SET> and	235	C<ASN_OBJECT_IDENTIFIER>, C<ASN_SEQUENCE>, C<ASN_SET> and
147	C<ASN_IA5_STRING>.	236	C<ASN_IA5_STRING>.
148		237
149	The most common tags in SNMP's C<ASN_APPLICATION> namespace	238	The most common tags in SNMP's C<ASN_APPLICATION> namespace are
150	are C<SNMP_IPADDRESS>, C<SNMP_COUNTER32>, C<SNMP_UNSIGNED32>,	239	C<SNMP_COUNTER32>, C<SNMP_UNSIGNED32>, C<SNMP_TIMETICKS> and
151	C<SNMP_TIMETICKS>, C<SNMP_OPAQUE> and C<SNMP_COUNTER64>.	240	C<SNMP_COUNTER64>.
152		241
153	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
154	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
155	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>,
156	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
157	en-/decode as BER tuples themselves.	246	subvalues which this module will en-/decode as BER tuples themselves.
158		247
159	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
160	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
161	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
162	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
163	interpret the namespace/tag.	252	interpret the namespace/tag.
164		253
165	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
166	string in place of some nice decoded value.	255	string in place of some nice decoded value.
167		256
…		…
169		258
170	=head2 DECODING AND ENCODING	259	=head2 DECODING AND ENCODING
171		260
172	=over	261	=over
173		262
174	=item $tuple = ber_decoded $bindata	263	=item $tuple = ber_decode $bindata[, $profile]
175		264
176	Decodes binary BER data in C<$bindata> and returns the resulting BER	265	Decodes binary BER data in C<$bindata> and returns the resulting BER
177	tuple. Croaks on any decoding error, so the returned C<$tuple> is always	266	tuple. Croaks on any decoding error, so the returned C<$tuple> is always
178	valid.	267	valid.
179		268
		269	How tags are interpreted is defined by the second argument, which must
		270	be a C<Convert::BER::XS::Profile> object. If it is missing, the default
		271	profile will be used (C<$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
180	=item $bindata = ber_encode $tuple	298	=item $bindata = ber_encode $tuple[, $profile]
181		299
182	Encodes the BER tuple into a BER/DER data structure.	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).
183		305
184	=back	306	=back
185		307
186	=head2 HELPER FUNCTIONS	308	=head2 HELPER FUNCTIONS
187		309
188	Working with a 4-tuple for every value can be annoying. Or, rather, I<is>	310	Working with a 4-tuple for every value can be annoying. Or, rather, I<is>
189	annoying. To reduce this a bit, this module defines a number of helper	311	annoying. To reduce this a bit, this module defines a number of helper
190	functions, both to match BER tuples and to conmstruct BER tuples:	312	functions, both to match BER tuples and to construct BER tuples:
191		313
192	=head3 MATCH HELPERS	314	=head3 MATCH HELPERS
193		315
194	Thse functions accept a BER tuple as first argument and either paertially	316	These functions accept a BER tuple as first argument and either partially
195	or fully match it. They often come in two forms, one which exactly matches	317	or fully match it. They often come in two forms, one which exactly matches
196	a value, and one which only matches the type and returns the value.	318	a value, and one which only matches the type and returns the value.
197		319
198	They do check whether valid tuples are passed in and croak otherwise. As	320	They do check whether valid tuples are passed in and croak otherwise. As
199	a ease-of-use exception, they usually also accept C<undef> instead of a	321	a ease-of-use exception, they usually also accept C<undef> instead of a
200	tuple reference. in which case they silently fail to match.	322	tuple reference, in which case they silently fail to match.
201		323
202	=over	324	=over
203		325
204	=item $bool = ber_is $tuple, $class, $tag, $constructed, $data	326	=item $bool = ber_is $tuple, $class, $tag, $flags, $data
205		327
206	This takes a BER C<$tuple> and matches its elements agains the privded	328	This takes a BER C<$tuple> and matches its elements against the provided
207	values, all of which are optional - values that are either missing or	329	values, all of which are optional - values that are either missing or
208	C<undef> will be ignored, the others will be matched exactly (e.g. as if	330	C<undef> will be ignored, the others will be matched exactly (e.g. as if
209	you used C<==> or C<eq> (for C<$data>)).	331	you used C<==> or C<eq> (for C<$data>)).
210		332
211	Some examples:	333	Some examples:
…		…
214	orf die "tuple is not an ASN SEQUENCE";	336	orf die "tuple is not an ASN SEQUENCE";
215		337
216	ber_is $tuple, ASN_UNIVERSAL, ASN_NULL	338	ber_is $tuple, ASN_UNIVERSAL, ASN_NULL
217	or die "tuple is not an ASN NULL value";	339	or die "tuple is not an ASN NULL value";
218		340
219	ber_is $tuple, ASN_UNIVERSAL, ASN_INTEGER32, 0, 50	341	ber_is $tuple, ASN_UNIVERSAL, ASN_INTEGER, 0, 50
220	or die "BER integer must be 50";	342	or die "BER integer must be 50";
221		343
222	=item $seq = ber_is_seq $tuple	344	=item $seq = ber_is_seq $tuple
223		345
224	Returns the sequence members (the array of subvalues) if the C<$tuple> is	346	Returns the sequence members (the array of subvalues) if the C<$tuple> is
…		…
231	my $snmp = ber_is_seq $ber	353	my $snmp = ber_is_seq $ber
232	or die "SNMP packet invalid: does not start with SEQUENCE";	354	or die "SNMP packet invalid: does not start with SEQUENCE";
233		355
234	# now we know $snmp is a sequence, so decode the SNMP version	356	# now we know $snmp is a sequence, so decode the SNMP version
235		357
236	my $version = ber_is_i32 $snmp->[0]	358	my $version = ber_is_int $snmp->[0]
237	or die "SNMP packet invalid: does not start with version number";	359	or die "SNMP packet invalid: does not start with version number";
238		360
239	=item $bool = ber_is_i32 $tuple, $i32	361	=item $bool = ber_is_int $tuple, $int
240		362
241	Returns a true value if the C<$tuple> represents an ASN INTEGER32 with	363	Returns a true value if the C<$tuple> represents an ASN INTEGER with
242	the value C<$i32>.	364	the value C<$int>.
243		365
244	=item $i32 = ber_is_i32 $tuple	366	=item $int = ber_is_int $tuple
245		367
246	Returns true (and extracts the integer value) if the C<$tuple> is an ASN	368	Returns true (and extracts the integer value) if the C<$tuple> is an
247	INTEGER32. For C<0>, this function returns a special value that is 0 but	369	C<ASN_INTEGER>. For C<0>, this function returns a special value that is 0
248	true.	370	but true.
249		371
250	=item $bool = ber_is_oid $tuple, $oid_string	372	=item $bool = ber_is_oid $tuple, $oid_string
251		373
252	Returns true if the C<$tuple> represents an ASN_OBJECT_IDENTIFIER	374	Returns true if the C<$tuple> represents an ASN_OBJECT_IDENTIFIER
253	that exactly matches C<$oid_string>. Example:	375	that exactly matches C<$oid_string>. Example:
…		…
264		386
265	=head3 CONSTRUCTION HELPERS	387	=head3 CONSTRUCTION HELPERS
266		388
267	=over	389	=over
268		390
269	=item $tuple = ber_i32 $value	391	=item $tuple = ber_int $value
270		392
271	Constructs a new C<ASN_INTEGER32> tuple.	393	Constructs a new C<ASN_INTEGER> tuple.
272		394
273	=back	395	=back
274		396
275	=head2 RELATIONSHIP TO L<Convert::BER> and L<Convert::ASN1>	397	=head2 RELATIONSHIP TO L<Convert::BER> and L<Convert::ASN1>
276		398
…		…
286	use common::sense;	408	use common::sense;
287		409
288	use XSLoader ();	410	use XSLoader ();
289	use Exporter qw(import);	411	use Exporter qw(import);
290		412
		413	use Carp ();
		414
291	our $VERSION;	415	our $VERSION;
292		416
293	BEGIN {	417	BEGIN {
294	$VERSION = 0.8;	418	$VERSION = 1.21;
295	XSLoader::load __PACKAGE__, $VERSION;	419	XSLoader::load __PACKAGE__, $VERSION;
296	}	420	}
297		421
298	our %EXPORT_TAGS = (	422	our %EXPORT_TAGS = (
299	const => [qw(	423	const_index => [qw(
300	BER_CLASS BER_TAG BER_CONSTRUCTED BER_DATA	424	BER_CLASS BER_TAG BER_FLAGS BER_DATA
301		425	)],
		426	const_asn_class => [qw(
		427	ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE
		428	)],
		429	const_asn_tag => [qw(
302	ASN_BOOLEAN ASN_INTEGER32 ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER	430	ASN_BOOLEAN ASN_INTEGER ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OID ASN_OBJECT_IDENTIFIER
303	ASN_OBJECT_DESCRIPTOR ASN_OID ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED	431	ASN_OBJECT_DESCRIPTOR ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED
304	ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING	432	ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING
305	ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING	433	ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING
306	ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING	434	ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING
307	ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING	435	ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING
308		436	)],
309	ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE	437	const_ber_type => [qw(
310
311	BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT	438	BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT
312	BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL	439	BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL
313	BER_TYPE_IPADDRESS BER_TYPE_CROAK	440	BER_TYPE_IPADDRESS BER_TYPE_CROAK
314	)],	441	)],
315	const_snmp => [qw(	442	const_snmp => [qw(
316	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64	443	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_GAUGE32 SNMP_UNSIGNED32
		444	SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
		445	)],
		446	decode => [qw(
		447	ber_decode ber_decode_prefix
		448	ber_is ber_is_seq ber_is_int ber_is_oid
		449	ber_dump
317	)],	450	)],
318	encode => [qw(	451	encode => [qw(
319	ber_decode
320	ber_is ber_is_seq ber_is_i32 ber_is_oid
321	)],
322	decode => [qw(
323	ber_encode	452	ber_encode
324	ber_i32	453	ber_int
325	)],	454	)],
326	);	455	);
327		456
328	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;	457	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;
329		458
330	$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)];
		462
		463	our $DEFAULT_PROFILE = new Convert::BER::XS::Profile;
		464
		465	$DEFAULT_PROFILE->_set_default;
		466
		467	# additional SNMP application types
		468	our $SNMP_PROFILE = new Convert::BER::XS::Profile;
		469
		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, $_[2];
		617	}
331		618
332	=head1 PROFILES	619	=head1 PROFILES
333		620
334	While any BER data can be correctly encoded and decoded out of the box, it	621	While any BER data can be correctly encoded and decoded out of the box, it
335	can be inconvenient to have to manually decode some values into a "better"	622	can be inconvenient to have to manually decode some values into a "better"
…		…
361	=item C<$Convert::BER::XS::SNMP_PROFILE>	648	=item C<$Convert::BER::XS::SNMP_PROFILE>
362		649
363	A profile with mappings for SNMP-specific application tags added. This is	650	A profile with mappings for SNMP-specific application tags added. This is
364	useful when de-/encoding SNMP data.	651	useful when de-/encoding SNMP data.
365		652
		653	The L<Example Profile> section, below, shows how this profile is being
		654	constructed.
		655
366	Example:	656	Example:
367		657
368	$ber = ber_decode $data, $Convert::BER::XS::SNMP_PROFILE;	658	$ber = ber_decode $data, $Convert::BER::XS::SNMP_PROFILE;
369		659
370	=back	660	=back
…		…
396		686
397	Returns the BER type mapped to the given C<$class>/C<$tag> combination.	687	Returns the BER type mapped to the given C<$class>/C<$tag> combination.
398		688
399	=back	689	=back
400		690
401	=head2 BER TYPES	691	=head2 BER Types
402		692
403	This lists the predefined BER types - you can map any C<CLASS>/C<TAG>	693	This lists the predefined BER types. BER types are formatters used
404	combination to any C<BER_TYPE_*>.	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.
405		697
406	=over	698	=over
407		699
408	=item C<BER_TYPE_BYTES>	700	=item C<BER_TYPE_BYTES>
409		701
…		…
438	dot, e.g. C<1.3.6.1.213>.	730	dot, e.g. C<1.3.6.1.213>.
439		731
440	=item C<BER_TYPE_RELOID>	732	=item C<BER_TYPE_RELOID>
441		733
442	Same as C<BER_TYPE_OID> but uses relative object identifier	734	Same as C<BER_TYPE_OID> but uses relative object identifier
443	encoding: ASN.1 has this hack of encoding the first two OID components	735	encoding: ASN.1 uses some hack encoding of the first two OID components
444	into a single integer in a weird attempt to save an insignificant amount	736	into a single integer in a weird attempt to save an insignificant amount
445	of space in an otherwise wasteful encoding, and relative OIDs are	737	of space in an otherwise wasteful encoding, and relative OIDs are
446	basically OIDs without this hack. The practical difference is that the	738	basically OIDs without this hack. The practical difference is that the
447	second component of an OID can only have the values 1..40, while relative	739	second component of an OID can only have the values 1..40, while relative
448	OIDs do not have this restriction.	740	OIDs do not have this restriction.
…		…
475	C<BER_TYPE_BYTES>. When you don't want that but instead prefer a hard	767	C<BER_TYPE_BYTES>. When you don't want that but instead prefer a hard
476	error for some types, then C<BER_TYPE_CROAK> is for you.	768	error for some types, then C<BER_TYPE_CROAK> is for you.
477		769
478	=back	770	=back
479		771
480	=cut	772	=head2 Example Profile
481		773
482	our $DEFAULT_PROFILE = new Convert::BER::XS::Profile;	774	The following creates a profile suitable for SNMP - it's exactly identical
		775	to the C<$Convert::BER::XS::SNMP_PROFILE> profile.
		776
483	our $SNMP_PROFILE = new Convert::BER::XS::Profile;	777	our $SNMP_PROFILE = new Convert::BER::XS::Profile;
484		778
485	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS);	779	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS);
486	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT);	780	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT);
487	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT);	781	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT);
488	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT);	782	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT);
489	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_IPADDRESS);	783	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_BYTES);
490	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT);	784	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT);
491		785
492	$DEFAULT_PROFILE->_set_default;
493
494	1;
495
496	=head2 LIMITATIONS	786	=head2 LIMITATIONS/NOTES
497		787
498	This module can only en-/decode 64 bit signed and unsigned integers, and	788	This module can only en-/decode 64 bit signed and unsigned
499	only when your perl supports those.	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>.
500		796
501	OBJECT IDENTIFIEERs cannot have unlimited length, although the limit is	797	OBJECT IDENTIFIEERs cannot have unlimited length, although the limit is
502	much larger than e.g. the one imposed by SNMP or other protocols.	798	much larger than e.g. the one imposed by SNMP or other protocols, and is
		799	about 4kB.
503		800
504	REAL values are not supported and will croak.	801	Constructed strings are decoded just fine, but there should be a way to
		802	join them for convenience.
505		803
506	This module has undergone little to no testing so far.	804	REAL values will always be encoded in decimal form and ssometimes is
		805	forced into a perl "NV" type, potentially losing precision.
507		806
508	=head2 ITHREADS SUPPORT	807	=head2 ITHREADS SUPPORT
509		808
510	This module is unlikely to work when the (officially discouraged) ithreads	809	This module is unlikely to work in any other than the loading thread when
511	are in use.	810	the (officially discouraged) ithreads are in use.
512		811
513	=head1 AUTHOR	812	=head1 AUTHOR
514		813
515	Marc Lehmann <schmorp@schmorp.de>	814	Marc Lehmann <schmorp@schmorp.de>
516	http://software.schmorp.de/pkg/Convert-BER-XS	815	http://software.schmorp.de/pkg/Convert-BER-XS
517		816
518	=cut	817	=cut
519		818
		819	1;
		820

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing Convert-BER-XS/XS.pm (file contents): Revision 1.18 by root, Sat Apr 20 13:48:53 2019 UTC vs. Revision 1.63 by root, Wed Mar 3 05:30:23 2021 UTC

Diff Legend

Comparing Convert-BER-XS/XS.pm (file contents):
Revision 1.18 by root, Sat Apr 20 13:48:53 2019 UTC vs.
Revision 1.63 by root, Wed Mar 3 05:30:23 2021 UTC