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

Comparing Convert-BER-XS/XS.pm (file contents):
Revision 1.6 by root, Fri Apr 19 20:38:38 2019 UTC vs.
Revision 1.59 by root, Fri May 3 08:49:01 2019 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	my $ber = ber_decode $buf, $Convert::BER::XS::SNMP_PROFILE
10	or die "unable to decode SNMP message";	10	or die "unable to decode SNMP message";
11		11
12	# The above results in a data structure consisting of (class, tag,	12	# The above results in a data structure consisting of
		13	# (class, tag, flags, data)
13	# constructed, data) tuples. Below is such a message, SNMPv1 trap	14	# tuples. Below is such a message, SNMPv1 trap
14	# with a Cisco mac change notification.	15	# with a Cisco mac change notification.
15	# Did you know that Cisco is in the news almost every week because	16	# Did you know that Cisco is in the news almost
		17	# every week because of some backdoor password
16	# of some backdoor password or other extremely stupid security bug?	18	# or other extremely stupid security bug?
17		19
18	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1,	20	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1,
19	[	21	[
20	[ ASN_UNIVERSAL, ASN_INTEGER32, 0, 0 ], # snmp version 1	22	[ ASN_UNIVERSAL, ASN_INTEGER, 0, 0 ], # snmp version 1
21	[ ASN_UNIVERSAL, 4, 0, "public" ], # community	23	[ ASN_UNIVERSAL, 4, 0, "public" ], # community
22	[ ASN_CONTEXT, 4, 1, # CHOICE, constructed - trap PDU	24	[ ASN_CONTEXT, 4, 1, # CHOICE, constructed - trap PDU
23	[	25	[
24	[ ASN_UNIVERSAL, ASN_OBJECT_IDENTIFIER, 0, "1.3.6.1.4.1.9.9.215.2" ], # enterprise oid	26	[ ASN_UNIVERSAL, ASN_OBJECT_IDENTIFIER, 0, "1.3.6.1.4.1.9.9.215.2" ], # enterprise oid
25	[ ASN_APPLICATION, 0, 0, "\x0a\x00\x00\x01" ], # SNMP IpAddress, 10.0.0.1	27	[ ASN_APPLICATION, SNMP_IPADDRESS, 0, "10.0.0.1" ], # SNMP IpAddress
26	[ ASN_UNIVERSAL, ASN_INTEGER32, 0, 6 ], # generic trap	28	[ ASN_UNIVERSAL, ASN_INTEGER, 0, 6 ], # generic trap
27	[ ASN_UNIVERSAL, ASN_INTEGER32, 0, 1 ], # specific trap	29	[ ASN_UNIVERSAL, ASN_INTEGER, 0, 1 ], # specific trap
28	[ ASN_APPLICATION, ASN_TIMETICKS, 0, 1817903850 ], # SNMP TimeTicks	30	[ ASN_APPLICATION, SNMP_TIMETICKS, 0, 1817903850 ], # SNMP TimeTicks
29	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # the varbindlist	31	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # the varbindlist
30	[	32	[
31	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # a single varbind, "key value" pair	33	[ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # a single varbind, "key value" pair
32	[	34	[
33	[ ASN_UNIVERSAL, ASN_OBJECT_IDENTIFIER, 0, "1.3.6.1.4.1.9.9.215.1.1.8.1.2.1" ], # the oid	35	[ ASN_UNIVERSAL, ASN_OBJECT_IDENTIFIER, 0, "1.3.6.1.4.1.9.9.215.1.1.8.1.2.1" ],
34	[ ASN_UNIVERSAL, ASN_OCTET_STRING, 0, "...data..." # the value	36	[ ASN_UNIVERSAL, ASN_OCTET_STRING, 0, "...data..." # the value
35	]	37	]
36	]	38	]
37	],	39	],
38	...	40	...
		41	# let's dump it, for debugging
		42
		43	ber_dump $ber, $Convert::BER::XS::SNMP_PROFILE;
39		44
40	# let's decode it a bit with some helper functions	45	# let's decode it a bit with some helper functions
41		46
42	my $msg = ber_is_seq $ber	47	my $msg = ber_is_seq $ber
43	or die "SNMP message does not start with a sequence";	48	or die "SNMP message does not start with a sequence";
44		49
45	ber_is $msg->[0], ASN_UNIVERSAL, ASN_INTEGER32, 0	50	ber_is $msg->[0], ASN_UNIVERSAL, ASN_INTEGER, 0
46	or die "SNMP message does not start with snmp version\n";	51	or die "SNMP message does not start with snmp version\n";
47		52
48	# message is SNMP v1 or v2c?	53	# message is SNMP v1 or v2c?
49	if ($msg->[0][BER_DATA] == 0 \|\| $msg->[0][BER_DATA] == 1) {	54	if ($msg->[0][BER_DATA] == 0 \|\| $msg->[0][BER_DATA] == 1) {
50		55
…		…
53	my $trap = $msg->[2][BER_DATA];	58	my $trap = $msg->[2][BER_DATA];
54		59
55	# check whether trap is a cisco mac notification mac changed message	60	# check whether trap is a cisco mac notification mac changed message
56	if (	61	if (
57	(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
58	and (ber_is_i32 $trap->[2], 6)	63	and (ber_is_int $trap->[2], 6)
59	and (ber_is_i32 $trap->[3], 1) # mac changed msg	64	and (ber_is_int $trap->[3], 1) # mac changed msg
60	) {	65	) {
61	... and so on	66	... and so on
62		67
63	# finally, let's encode it again and hope it results in the same bit pattern	68	# finally, let's encode it again and hope it results in the same bit pattern
64		69
65	my $buf = ber_encode $ber;	70	my $buf = ber_encode $ber, $Convert::BER::XS::SNMP_PROFILE;
66		71
67	=head1 DESCRIPTION	72	=head1 DESCRIPTION
68		73
		74	WARNING: Before release 1.0, the API is not considered stable in any way.
		75
69	This module implements a I<very> low level BER/DER en-/decoder.	76	This module implements a I<very> low level BER/DER en-/decoder.
70		77
71	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
72	level of user-friendlyness.	79	level of user-friendlyness.
73		80
74	Currently, not much is documented, as this is an initial release to	81	=head2 EXPORT TAGS AND CONSTANTS
75	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 the 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
76		161
77	=head2 ASN.1/BER/DER/... BASICS	162	=head2 ASN.1/BER/DER/... BASICS
78		163
79	ASN.1 is a strange language that can be sed to describe protocols and	164	ASN.1 is a strange language that can be used to describe protocols and
80	data structures. It supports various mappings to JSON, XML, but most	165	data structures. It supports various mappings to JSON, XML, but most
81	importantly, to a various binary encodings such as BER, that is the topic	166	importantly, to a various binary encodings such as BER, that is the topic
82	of this module, and is used in SNMP or LDAP for example.	167	of this module, and is used in SNMP, LDAP or X.509 for example.
83		168
84	While ASN.1 defines a schema that is useful to interpret encoded data,	169	While ASN.1 defines a schema that is useful to interpret encoded data,
85	the BER encoding is actually somehat self-describing: you might not know	170	the BER encoding is actually somewhat self-describing: you might not know
86	whether something is a string or a number or a sequence or something else,	171	whether something is a string or a number or a sequence or something else,
87	but you can nevertheless decode the overall structure, even if you end up	172	but you can nevertheless decode the overall structure, even if you end up
88	with just a binary blob for the actual value.	173	with just a binary blob for the actual value.
89		174
90	This works because BER values are tagged with a type and a namespace,	175	This works because BER values are tagged with a type and a namespace,
91	and also have a flag that says whther a value consists of subvalues (is	176	and also have a flag that says whether a value consists of subvalues (is
92	"constructed") or not (is "primitive").	177	"constructed") or not (is "primitive").
93		178
94	Tags are simple integers, and ASN.1 defines a somewhat weird assortment of	179	Tags are simple integers, and ASN.1 defines a somewhat weird assortment
95	those - for example, you have 32 bit signed integers and 16(!) different	180	of those - for example, you have one integers and 16(!) different
96	string types, but there is no unsigned32 type for example. Different	181	string types, but there is no Unsigned32 type for example. Different
97	applications work around this in different ways, for example, SNMP defines	182	applications work around this in different ways, for example, SNMP defines
98	application-specific Gauge32, Counter32 and Unsigned32, which are mapped	183	application-specific Gauge32, Counter32 and Unsigned32, which are mapped
99	to two different tags: you can distinguish between Counter32 and the	184	to two different tags: you can distinguish between Counter32 and the
100	others, but not between Gause32 and Unsigned32, without the ASN.1 schema.	185	others, but not between Gause32 and Unsigned32, without the ASN.1 schema.
101		186
…		…
104	=head2 DECODED BER REPRESENTATION	189	=head2 DECODED BER REPRESENTATION
105		190
106	This module represents every BER value as a 4-element tuple (actually an	191	This module represents every BER value as a 4-element tuple (actually an
107	array-reference):	192	array-reference):
108		193
109	[CLASS, TAG, CONSTRUCTED, DATA]	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
110		202
111	To avoid non-descriptive hardcoded array index numbers, this module	203	To avoid non-descriptive hardcoded array index numbers, this module
112	defines symbolic constants to access these members: C<BER_CLASS>,	204	defines symbolic constants to access these members: C<BER_CLASS>,
113	C<BER_TAG>, C<BER_CONSTRUCTED> and C<BER_DATA>.	205	C<BER_TAG>, C<BER_FLAGS> and C<BER_DATA>.
114		206
115	Also, the first three members are integers with a little caveat: for	207	Also, the first three members are integers with a little caveat: for
116	performance reasons, these are readonly and shared, so you must not modify	208	performance reasons, these are readonly and shared, so you must not modify
117	them (increment, assign to them etc.) in any way. You may modify the	209	them (increment, assign to them etc.) in any way. You may modify the
118	I<DATA> member, and you may re-assign the array itself, e.g.:	210	I<DATA> member, and you may re-assign the array itself, e.g.:
119		211
120	$ber = ber_decode $binbuf;	212	$ber = ber_decode $binbuf;
121		213
122	# the following is NOT legal:	214	# the following is NOT legal:
123	$ber->[BER_CLASS] = ASN_PRIVATE; # ERROR, readonly(!)	215	$ber->[BER_CLASS] = ASN_PRIVATE; # ERROR, CLASS/TAG/FLAGS are READ ONLY(!)
124		216
125	# but all of the following are fine:	217	# but all of the following are fine:
126	$ber->[BER_DATA] = "string";	218	$ber->[BER_DATA] = "string";
127	$ber->[BER_DATA] = [ASN_UNIVERSAL, ASN_INTEGER32, 0, 123];	219	$ber->[BER_DATA] = [ASN_UNIVERSAL, ASN_INTEGER, 0, 123];
128	@$ber = (ASN_APPLICATION, SNMP_TIMETICKS, 1000);	220	@$ber = (ASN_APPLICATION, SNMP_TIMETICKS, 0, 1000);
129		221
130	I<CLASS> is something like a namespace for I<TAG>s - there is the	222	I<CLASS> is something like a namespace for I<TAG>s - there is the
131	C<ASN_UNIVERSAL> namespace which defines tags common to all ASN.1	223	C<ASN_UNIVERSAL> namespace which defines tags common to all ASN.1
132	implementations, the C<ASN_APPLICATION> namespace which defines tags for	224	implementations, the C<ASN_APPLICATION> namespace which defines tags for
133	specific applications (for example, the SNMP C<Unsigned32> type is in this	225	specific applications (for example, the SNMP C<Unsigned32> type is in this
134	namespace), a special-purpose context namespace (C<ASN_CONTEXT>, used e.g.	226	namespace), a special-purpose context namespace (C<ASN_CONTEXT>, used e.g.
135	for C<CHOICE>) and a private namespace (C<ASN_PRIVATE>).	227	for C<CHOICE>) and a private namespace (C<ASN_PRIVATE>).
136		228
137	The meaning of the I<TAG> depends on the namespace, and defines a	229	The meaning of the I<TAG> depends on the namespace, and defines a
138	(partial) interpretation of the data value. For example, right now, SNMP	230	(partial) interpretation of the data value. For example, SNMP defines
139	application namespace knowledge ix hardcoded into this module, so it	231	extra tags in the C<ASN_APPLICATION> namespace, and to take full advantage
140	knows that SNMP C<Unsigned32> values need to be decoded into actual perl	232	of these, you need to tell this module how to handle those via profiles.
141	integers.
142		233
143	The most common tags in the C<ASN_UNIVERSAL> namespace are	234	The most common tags in the C<ASN_UNIVERSAL> namespace are
144	C<ASN_INTEGER32>, C<ASN_BIT_STRING>, C<ASN_NULL>, C<ASN_OCTET_STRING>,	235	C<ASN_INTEGER>, C<ASN_BIT_STRING>, C<ASN_NULL>, C<ASN_OCTET_STRING>,
145	C<ASN_OBJECT_IDENTIFIER>, C<ASN_SEQUENCE>, C<ASN_SET> and	236	C<ASN_OBJECT_IDENTIFIER>, C<ASN_SEQUENCE>, C<ASN_SET> and
146	C<ASN_IA5_STRING>.	237	C<ASN_IA5_STRING>.
147		238
148	The most common tags in SNMP's C<ASN_APPLICATION> namespace	239	The most common tags in SNMP's C<ASN_APPLICATION> namespace are
149	are C<SNMP_IPADDRESS>, C<SNMP_COUNTER32>, C<SNMP_UNSIGNED32>,	240	C<SNMP_COUNTER32>, C<SNMP_UNSIGNED32>, C<SNMP_TIMETICKS> and
150	C<SNMP_TIMETICKS>, C<SNMP_OPAQUE> and C<SNMP_COUNTER64>.	241	C<SNMP_COUNTER64>.
151		242
152	The I<CONSTRUCTED> flag is really just a boolean - if it is false, the	243	The I<FLAGS> value is really just a boolean at this time (but might
153	the value is "primitive" and contains no subvalues, kind of like a	244	get extended) - if it is C<0>, the value is "primitive" and contains
154	non-reference perl scalar. IF it is true, then the value is "constructed"	245	no subvalues, kind of like a non-reference perl scalar. If it is C<1>,
155	which just means it contains a list of subvalues which this module will	246	then the value is "constructed" which just means it contains a list of
156	en-/decode as BER tuples themselves.	247	subvalues which this module will en-/decode as BER tuples themselves.
157		248
158	The I<DATA> value is either a reference to an array of further tuples (if	249	The I<DATA> value is either a reference to an array of further tuples
159	the value is I<CONSTRUCTED>), some decoded representation of the value,	250	(if the value is I<FLAGS>), some decoded representation of the value, if
160	if this module knows how to decode it (e.g. for the integer types above)	251	this module knows how to decode it (e.g. for the integer types above) or
161	or a binary string with the raw octets if this module doesn't know how to	252	a binary string with the raw octets if this module doesn't know how to
162	interpret the namespace/tag.	253	interpret the namespace/tag.
163		254
164	Thus, you can always decode a BER data structure and at worst you get a	255	Thus, you can always decode a BER data structure and at worst you get a
165	string in place of some nice decoded value.	256	string in place of some nice decoded value.
166		257
167	See the SYNOPSIS for an example of such an encoded tuple representation.	258	See the SYNOPSIS for an example of such an encoded tuple representation.
168		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
169	=head2 HELPER FUNCTIONS	309	=head2 HELPER FUNCTIONS
170		310
171	Working with a 4-tuple for every value can be annoying. Or, rather, I<is>	311	Working with a 4-tuple for every value can be annoying. Or, rather, I<is>
172	annoying. To reduce this a bit, this module defines a number of helper	312	annoying. To reduce this a bit, this module defines a number of helper
173	functions, both to match BER tuples and to conmstruct BER tuples:	313	functions, both to match BER tuples and to construct BER tuples:
174		314
175	=head3 MATCH HELPERS	315	=head3 MATCH HELPERS
176		316
177	Thse functions accept a BER tuple as first argument and either paertially	317	These functions accept a BER tuple as first argument and either partially
178	or fully match it. They often come in two forms, one which exactly matches	318	or fully match it. They often come in two forms, one which exactly matches
179	a value, and one which only matches the type and returns the value.	319	a value, and one which only matches the type and returns the value.
180		320
181	They do check whether valid tuples are passed in and croak otherwise. As	321	They do check whether valid tuples are passed in and croak otherwise. As
182	a ease-of-use exception, they usually also accept C<undef> instead of a	322	a ease-of-use exception, they usually also accept C<undef> instead of a
183	tuple reference. in which case they silently fail to match.	323	tuple reference, in which case they silently fail to match.
184		324
185	=over	325	=over
186		326
187	=item $bool = ber_is $tuple, $class, $tag, $constructed, $data	327	=item $bool = ber_is $tuple, $class, $tag, $flags, $data
188		328
189	This takes a BER C<$tuple> and matches its elements agains the privded	329	This takes a BER C<$tuple> and matches its elements against the provided
190	values, all of which are optional - values that are either missing or	330	values, all of which are optional - values that are either missing or
191	C<undef> will be ignored, the others will be matched exactly (e.g. as if	331	C<undef> will be ignored, the others will be matched exactly (e.g. as if
192	you used C<==> or C<eq> (for C<$data>)).	332	you used C<==> or C<eq> (for C<$data>)).
193		333
194	Some examples:	334	Some examples:
…		…
197	orf die "tuple is not an ASN SEQUENCE";	337	orf die "tuple is not an ASN SEQUENCE";
198		338
199	ber_is $tuple, ASN_UNIVERSAL, ASN_NULL	339	ber_is $tuple, ASN_UNIVERSAL, ASN_NULL
200	or die "tuple is not an ASN NULL value";	340	or die "tuple is not an ASN NULL value";
201		341
202	ber_is $tuple, ASN_UNIVERSAL, ASN_INTEGER32, 0, 50	342	ber_is $tuple, ASN_UNIVERSAL, ASN_INTEGER, 0, 50
203	or die "BER integer must be 50";	343	or die "BER integer must be 50";
204		344
205	=item $seq = ber_is_seq $tuple	345	=item $seq = ber_is_seq $tuple
206		346
207	Returns the sequence members (the array of subvalues) if the C<$tuple> is	347	Returns the sequence members (the array of subvalues) if the C<$tuple> is
…		…
214	my $snmp = ber_is_seq $ber	354	my $snmp = ber_is_seq $ber
215	or die "SNMP packet invalid: does not start with SEQUENCE";	355	or die "SNMP packet invalid: does not start with SEQUENCE";
216		356
217	# now we know $snmp is a sequence, so decode the SNMP version	357	# now we know $snmp is a sequence, so decode the SNMP version
218		358
219	my $version = ber_is_i32 $snmp->[0]	359	my $version = ber_is_int $snmp->[0]
220	or die "SNMP packet invalid: does not start with version number";	360	or die "SNMP packet invalid: does not start with version number";
221		361
222	=item $bool = ber_is_i32 $tuple, $i32	362	=item $bool = ber_is_int $tuple, $int
223		363
224	Returns a true value if the C<$tuple> represents an ASN INTEGER32 with	364	Returns a true value if the C<$tuple> represents an ASN INTEGER with
225	the value C<$i32>.	365	the value C<$int>.
226		366
227	=item $i32 = ber_is_i32 $tuple	367	=item $int = ber_is_int $tuple
228		368
229	Returns true (and extracts the integer value) if the C<$tuple> is an ASN	369	Returns true (and extracts the integer value) if the C<$tuple> is an
230	INTEGER32. For C<0>, this function returns a special value that is 0 but	370	C<ASN_INTEGER>. For C<0>, this function returns a special value that is 0
231	true.	371	but true.
232		372
233	=item $bool = ber_is_oid $tuple, $oid_string	373	=item $bool = ber_is_oid $tuple, $oid_string
234		374
235	Returns true if the C<$tuple> represents an ASN_OBJECT_IDENTIFIER	375	Returns true if the C<$tuple> represents an ASN_OBJECT_IDENTIFIER
236	that exactly matches C$oid_string>. Exmaple:	376	that exactly matches C<$oid_string>. Example:
237		377
238	ber_is_oid $tuple, "1.3.6.1.4"	378	ber_is_oid $tuple, "1.3.6.1.4"
239	or die "oid must be 1.3.6.1.4";	379	or die "oid must be 1.3.6.1.4";
240		380
241	=item $oid = ber_is_oid $tuple	381	=item $oid = ber_is_oid $tuple
…		…
247		387
248	=head3 CONSTRUCTION HELPERS	388	=head3 CONSTRUCTION HELPERS
249		389
250	=over	390	=over
251		391
252	=item $tuple = ber_i32 $value	392	=item $tuple = ber_int $value
253		393
254	Constructs a new C<ASN_INTEGER32> tuple.	394	Constructs a new C<ASN_INTEGER> tuple.
255		395
256	=back	396	=back
257		397
258	=head2 RELATIONSHIP TO L<Convert::BER> and L<Convert::ASN1>	398	=head2 RELATIONSHIP TO L<Convert::BER> and L<Convert::ASN1>
259		399
…		…
269	use common::sense;	409	use common::sense;
270		410
271	use XSLoader ();	411	use XSLoader ();
272	use Exporter qw(import);	412	use Exporter qw(import);
273		413
		414	use Carp ();
		415
274	our $VERSION = 0.1;	416	our $VERSION;
275		417
		418	BEGIN {
		419	$VERSION = 1.2;
276	XSLoader::load __PACKAGE__, $VERSION;	420	XSLoader::load __PACKAGE__, $VERSION;
		421	}
277		422
278	our %EXPORT_TAGS = (	423	our %EXPORT_TAGS = (
		424	const_index => [qw(
		425	BER_CLASS BER_TAG BER_FLAGS BER_DATA
		426	)],
		427	const_asn_class => [qw(
		428	ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE
		429	)],
		430	const_asn_tag => [qw(
		431	ASN_BOOLEAN ASN_INTEGER ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OID ASN_OBJECT_IDENTIFIER
		432	ASN_OBJECT_DESCRIPTOR ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED
		433	ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING
		434	ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING
		435	ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING
		436	ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING
		437	)],
		438	const_ber_type => [qw(
		439	BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT
		440	BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL
		441	BER_TYPE_IPADDRESS BER_TYPE_CROAK
		442	)],
279	const => [qw(	443	const_snmp => [qw(
280	BER_CLASS BER_TAG BER_CONSTRUCTED BER_DATA	444	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_GAUGE32 SNMP_UNSIGNED32
281		445	SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
282	ASN_BOOLEAN ASN_INTEGER32 ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER ASN_TAG_BER ASN_TAG_MASK	446	)],
283	ASN_CONSTRUCTED ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE ASN_CLASS_MASK ASN_CLASS_SHIFT	447	decode => [qw(
284	ASN_SEQUENCE	448	ber_decode ber_decode_prefix
285		449	ber_is ber_is_seq ber_is_int ber_is_oid
286	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64	450	ber_dump
287	)],	451	)],
288	encode => [qw(	452	encode => [qw(
289	ber_decode
290	ber_is ber_is_seq ber_is_i32 ber_is_oid
291	)],
292	decode => [qw(
293	ber_encode	453	ber_encode
		454	ber_int
294	)],	455	)],
295	);	456	);
296		457
297	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;	458	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;
298		459
299	$EXPORT_TAGS{all} = \@EXPORT_OK;	460	$EXPORT_TAGS{all} = \@EXPORT_OK;
		461	$EXPORT_TAGS{const_asn} = [map @{ $EXPORT_TAGS{$_} }, qw(const_asn_class const_asn_tag)];
		462	$EXPORT_TAGS{const} = [map @{ $EXPORT_TAGS{$_} }, qw(const_index const_asn)];
300		463
301	1;	464	our $DEFAULT_PROFILE = new Convert::BER::XS::Profile;
302		465
303	=head2 BUGS / SHORTCOMINGs	466	$DEFAULT_PROFILE->_set_default;
304		467
305	This module does have a number of SNMPisms hardcoded, such as the SNMP	468	# additional SNMP application types
306	tags for Unsigned32 and so on. More configurability is needed, and, if	469	our $SNMP_PROFILE = new Convert::BER::XS::Profile;
307	ever implemented, will come in a form similar to how L<JSON::XS> and	470
308	L<CBOR::XS> respresent things, namely with an object-oriented interface.	471	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS);
		472	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , 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	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT);
		571
		572	sub _ber_dump {
		573	my ($ber, $profile, $indent) = @_;
		574
		575	if (my $seq = ber_is_seq $ber) {
		576	printf "%sSEQUENCE\n", $indent;
		577	&_ber_dump ($_, $profile, "$indent\| ")
		578	for @$seq;
		579	} else {
		580	my $asn = $ber->[BER_CLASS] == ASN_UNIVERSAL;
		581
		582	my $class = _re const_asn_class => $ber->[BER_CLASS];
		583	my $tag = $asn ? _re const_asn_tag => $ber->[BER_TAG] : $ber->[BER_TAG];
		584	my $type = _re const_ber_type => $profile->get ($ber->[BER_CLASS], $ber->[BER_TAG]);
		585	my $data = $ber->[BER_DATA];
		586
		587	if ($profile == $SNMP_PROFILE and $ber->[BER_CLASS] == ASN_APPLICATION) {
		588	$tag = _re const_snmp => $ber->[BER_TAG];
		589	} elsif (!$asn) {
		590	$tag = "$class ($tag)";
		591	}
		592
		593	$class =~ s/^ASN_//;
		594	$tag =~ s/^(ASN_\|SNMP_)//;
		595	$type =~ s/^BER_TYPE_//;
		596
		597	if ($ber->[BER_FLAGS]) {
		598	printf "$indent%-16.16s\n", $tag;
		599	&_ber_dump ($_, $profile, "$indent\| ")
		600	for @$data;
		601	} else {
		602	if ($data =~ y/\x20-\x7e//c / (length $data \|\| 1) > 0.2 or $data =~ /\x00./s) {
		603	# assume binary
		604	$data = unpack "H*", $data;
		605	} else {
		606	$data =~ s/[^\x20-\x7e]/./g;
		607	$data = "\"$data\"" if $tag =~ /string/i \|\| !length $data;
		608	}
		609
		610	substr $data, 40, 1e9, "..." if 40 < length $data;
		611
		612	printf "$indent%-16.16s %-6.6s %s\n", $tag, lc $type, $data;
		613	}
		614	}
		615	}
		616
		617	sub ber_dump($;$$) {
		618	_ber_dump $_[0], $_[1] \|\| $DEFAULT_PROFILE, $_[2];
		619	}
		620
		621	=head1 PROFILES
		622
		623	While any BER data can be correctly encoded and decoded out of the box, it
		624	can be inconvenient to have to manually decode some values into a "better"
		625	format: for instance, SNMP TimeTicks values are decoded into the raw octet
		626	strings of their BER representation, which is quite hard to decode. With
		627	profiles, you can change which class/tag combinations map to which decoder
		628	function inside C<ber_decode> (and of course also which encoder functions
		629	are used in C<ber_encode>).
		630
		631	This works by mapping specific class/tag combinations to an internal "ber
		632	type".
		633
		634	The default profile supports the standard ASN.1 types, but no
		635	application-specific ones. This means that class/tag combinations not in
		636	the base set of ASN.1 are decoded into their raw octet strings.
		637
		638	C<Convert::BER::XS> defines two profile variables you can use out of the box:
		639
		640	=over
		641
		642	=item C<$Convert::BER::XS::DEFAULT_PROFILE>
		643
		644	This is the default profile, i.e. the profile that is used when no
		645	profile is specified for de-/encoding.
		646
		647	You can modify it, but remember that this modifies the defaults for all
		648	callers that rely on the default profile.
		649
		650	=item C<$Convert::BER::XS::SNMP_PROFILE>
		651
		652	A profile with mappings for SNMP-specific application tags added. This is
		653	useful when de-/encoding SNMP data.
		654
		655	Example:
		656
		657	$ber = ber_decode $data, $Convert::BER::XS::SNMP_PROFILE;
		658
		659	=back
		660
		661	=head2 The Convert::BER::XS::Profile class
		662
		663	=over
		664
		665	=item $profile = new Convert::BER::XS::Profile
		666
		667	Create a new profile. The profile will be identical to the default
		668	profile.
		669
		670	=item $profile->set ($class, $tag, $type)
		671
		672	Sets the mapping for the given C<$class>/C<$tag> combination to C<$type>,
		673	which must be one of the C<BER_TYPE_*> constants.
		674
		675	Note that currently, the mapping is stored in a flat array, so large
		676	values of C<$tag> will consume large amounts of memory.
		677
		678	Example:
		679
		680	$profile = new Convert::BER::XS::Profile;
		681	$profile->set (ASN_APPLICATION, SNMP_COUNTER32, BER_TYPE_INT);
		682	$ber = ber_decode $data, $profile;
		683
		684	=item $type = $profile->get ($class, $tag)
		685
		686	Returns the BER type mapped to the given C<$class>/C<$tag> combination.
		687
		688	=back
		689
		690	=head2 BER Types
		691
		692	This lists the predefined BER types. BER types are formatters used
		693	internally to format and encode BER values. You can assign any C<BER_TYPE>
		694	to any C<CLASS>/C<TAG> combination tgo change how that tag is decoded or
		695	encoded.
		696
		697	=over
		698
		699	=item C<BER_TYPE_BYTES>
		700
		701	The raw octets of the value. This is the default type for unknown tags and
		702	de-/encodes the value as if it were an octet string, i.e. by copying the
		703	raw bytes.
		704
		705	=item C<BER_TYPE_UTF8>
		706
		707	Like C<BER_TYPE_BYTES>, but decodes the value as if it were a UTF-8 string
		708	(without validation!) and encodes a perl unicode string into a UTF-8 BER
		709	string.
		710
		711	=item C<BER_TYPE_UCS2>
		712
		713	Similar to C<BER_TYPE_UTF8>, but treats the BER value as UCS-2 encoded
		714	string.
		715
		716	=item C<BER_TYPE_UCS4>
		717
		718	Similar to C<BER_TYPE_UTF8>, but treats the BER value as UCS-4 encoded
		719	string.
		720
		721	=item C<BER_TYPE_INT>
		722
		723	Encodes and decodes a BER integer value to a perl integer scalar. This
		724	should correctly handle 64 bit signed and unsigned values.
		725
		726	=item C<BER_TYPE_OID>
		727
		728	Encodes and decodes an OBJECT IDENTIFIER into dotted form without leading
		729	dot, e.g. C<1.3.6.1.213>.
		730
		731	=item C<BER_TYPE_RELOID>
		732
		733	Same as C<BER_TYPE_OID> but uses relative object identifier
		734	encoding: ASN.1 has this hack of encoding the first two OID components
		735	into a single integer in a weird attempt to save an insignificant amount
		736	of space in an otherwise wasteful encoding, and relative OIDs are
		737	basically OIDs without this hack. The practical difference is that the
		738	second component of an OID can only have the values 1..40, while relative
		739	OIDs do not have this restriction.
		740
		741	=item C<BER_TYPE_NULL>
		742
		743	Decodes an C<ASN_NULL> value into C<undef>, and always encodes a
		744	C<ASN_NULL> type, regardless of the perl value.
		745
		746	=item C<BER_TYPE_BOOL>
		747
		748	Decodes an C<ASN_BOOLEAN> value into C<0> or C<1>, and encodes a perl
		749	boolean value into an C<ASN_BOOLEAN>.
		750
		751	=item C<BER_TYPE_REAL>
		752
		753	Decodes/encodes a BER real value. NOT IMPLEMENTED.
		754
		755	=item C<BER_TYPE_IPADDRESS>
		756
		757	Decodes/encodes a four byte string into an IPv4 dotted-quad address string
		758	in Perl. Given the obsolete nature of this type, this is a low-effort
		759	implementation that simply uses C<sprintf> and C<sscanf>-style conversion,
		760	so it won't handle all string forms supported by C<inet_aton> for example.
		761
		762	=item C<BER_TYPE_CROAK>
		763
		764	Always croaks when encountered during encoding or decoding - the
		765	default behaviour when encountering an unknown type is to treat it as
		766	C<BER_TYPE_BYTES>. When you don't want that but instead prefer a hard
		767	error for some types, then C<BER_TYPE_CROAK> is for you.
		768
		769	=back
		770
		771	=head2 Example Profile
		772
		773	The following creates a profile suitable for SNMP - it's exactly identical
		774	to the C<$Convert::BER::XS::SNMP_PROFILE> profile.
		775
		776	our $SNMP_PROFILE = new Convert::BER::XS::Profile;
		777
		778	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS);
		779	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT);
		780	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT);
		781	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT);
		782	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_BYTES);
		783	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT);
		784
		785	=head2 LIMITATIONS/NOTES
		786
		787	This module can only en-/decode 64 bit signed and unsigned
		788	integers/tags/lengths, and only when your perl supports those. So no UUID
		789	OIDs for now (unless you map the C<OBJECT IDENTIFIER> tag to something
		790	other than C<BER_TYPE_OID>).
		791
		792	This module does not generally care about ranges, i.e. it will happily
		793	de-/encode 64 bit integers into an C<SNMP_UNSIGNED32> value, or a negative
		794	number into an C<SNMP_COUNTER64>.
		795
		796	OBJECT IDENTIFIEERs cannot have unlimited length, although the limit is
		797	much larger than e.g. the one imposed by SNMP or other protocols, and is
		798	about 4kB.
		799
		800	Constructed strings are decoded just fine, but there should be a way to
		801	join them for convenience.
		802
		803	REAL values will always be encoded in decimal form and ssometimes is
		804	forced into a perl "NV" type, potentially losing precision.
		805
		806	=head2 ITHREADS SUPPORT
		807
		808	This module is unlikely to work in any other than the loading thread when
		809	the (officially discouraged) ithreads are in use.
309		810
310	=head1 AUTHOR	811	=head1 AUTHOR
311		812
312	Marc Lehmann <schmorp@schmorp.de>	813	Marc Lehmann <schmorp@schmorp.de>
313	http://software.schmorp.de/pkg/Convert-BER-XS	814	http://software.schmorp.de/pkg/Convert-BER-XS
314		815
315	=cut	816	=cut
316		817
		818	1;
		819

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Comparing Convert-BER-XS/XS.pm (file contents): Revision 1.6 by root, Fri Apr 19 20:38:38 2019 UTC vs. Revision 1.59 by root, Fri May 3 08:49:01 2019 UTC

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Comparing Convert-BER-XS/XS.pm (file contents):
Revision 1.6 by root, Fri Apr 19 20:38:38 2019 UTC vs.
Revision 1.59 by root, Fri May 3 08:49:01 2019 UTC