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

Comparing Convert-BER-XS/XS.pm (file contents):
Revision 1.12 by root, Fri Apr 19 21:24:31 2019 UTC vs.
Revision 1.40 by root, Sun Apr 21 00:42:15 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" ],	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
69	WARNING: Before release 1.0, the API is not considered stable in any way.	74	WARNING: Before release 1.0, the API is not considered stable in any way.
70		75
71	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.
72		77
73	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
74	level of user-friendlyness.	79	level of user-friendlyness.
75		80
76	Currently, not much is documented, as this is an initial release to	81	=head2 EXPORT TAGS AND CONSTANTS
77	reserve CPAN namespace, stay tuned for a few days.	82
		83	By default this module doesn't export any symbols, but if you don't want
		84	to break your keyboard, editor or eyesight with extremely long names, I
		85	recommend importing the C<:all> tag. Still, you can selectively import
		86	things.
		87
		88	=over
		89
		90	=item C<:all>
		91
		92	All of the below. Really. Recommended for at least first steps, or if you
		93	don't care about a few kilobytes of wasted memory (and namespace).
		94
		95	=item C<:const>
		96
		97	All of the strictly ASN.1-related constants defined by this module, the
		98	same as C<:const_asn :const_index>. Notably, this does not contain
		99	C<:const_ber_type> and C<:const_snmp>.
		100
		101	A good set to get everything you need to decode and match BER data would be
		102	C<:decode :const>.
		103
		104	=item C<:const_index>
		105
		106	The BER tuple array index constants:
		107
		108	BER_CLASS BER_TAG BER_FLAGS BER_DATA
		109
		110	=item C<:const_asn>
		111
		112	ASN class values (these are C<0>, C<1>, C<2> and C<3>, respectively -
		113	exactly thw two topmost bits from the identifier octet shifted 6 bits to
		114	the right):
		115
		116	ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE
		117
		118	ASN tag values (some of which are aliases, such as C<ASN_OID>). Their
		119	numerical value corresponds exactly to the numbers used in BER/X.690.
		120
		121	ASN_BOOLEAN ASN_INTEGER ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OID
		122	ASN_OBJECT_IDENTIFIER ASN_OBJECT_DESCRIPTOR ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED
		123	ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING
		124	ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING
		125	ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING
		126	ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING
		127
		128	=item C<:const_ber_type>
		129
		130	The BER type constants, explained in the PROFILES section.
		131
		132	BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT
		133	BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL
		134	BER_TYPE_IPADDRESS BER_TYPE_CROAK
		135
		136	=item C<:const_snmp>
		137
		138	Constants only relevant to SNMP. These are the tag values used by SNMP in
		139	the C<ASN_APPLICATION> namespace and have the exact numerical value as in
		140	BER/RFC 2578.
		141
		142	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_GAUGE32
		143	SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
		144
		145	=item C<:decode>
		146
		147	C<ber_decode> and the match helper functions:
		148
		149	ber_decode ber-decode_prefix
		150	ber_is ber_is_seq ber_is_int ber_is_oid
		151	ber_dump
		152
		153	=item C<:encode>
		154
		155	C<ber_encode> and the construction helper functions:
		156
		157	ber_encode
		158	ber_int
		159
		160	=back
78		161
79	=head2 ASN.1/BER/DER/... BASICS	162	=head2 ASN.1/BER/DER/... BASICS
80		163
81	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
82	data structures. It supports various mappings to JSON, XML, but most	165	data structures. It supports various mappings to JSON, XML, but most
83	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
84	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.
85		168
86	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,
87	the BER encoding is actually somewhat self-describing: you might not know	170	the BER encoding is actually somewhat self-describing: you might not know
88	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,
89	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
90	with just a binary blob for the actual value.	173	with just a binary blob for the actual value.
91		174
92	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,
93	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
94	"constructed") or not (is "primitive").	177	"constructed") or not (is "primitive").
95		178
96	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
97	those - for example, you have 32 bit signed integers and 16(!) different	180	of those - for example, you have one integers and 16(!) different
98	string types, but there is no unsigned32 type for example. Different	181	string types, but there is no Unsigned32 type for example. Different
99	applications work around this in different ways, for example, SNMP defines	182	applications work around this in different ways, for example, SNMP defines
100	application-specific Gauge32, Counter32 and Unsigned32, which are mapped	183	application-specific Gauge32, Counter32 and Unsigned32, which are mapped
101	to two different tags: you can distinguish between Counter32 and the	184	to two different tags: you can distinguish between Counter32 and the
102	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.
103		186
…		…
106	=head2 DECODED BER REPRESENTATION	189	=head2 DECODED BER REPRESENTATION
107		190
108	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
109	array-reference):	192	array-reference):
110		193
111	[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
112		202
113	To avoid non-descriptive hardcoded array index numbers, this module	203	To avoid non-descriptive hardcoded array index numbers, this module
114	defines symbolic constants to access these members: C<BER_CLASS>,	204	defines symbolic constants to access these members: C<BER_CLASS>,
115	C<BER_TAG>, C<BER_CONSTRUCTED> and C<BER_DATA>.	205	C<BER_TAG>, C<BER_FLAGS> and C<BER_DATA>.
116		206
117	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
118	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
119	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
120	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.:
121		211
122	$ber = ber_decode $binbuf;	212	$ber = ber_decode $binbuf;
123		213
124	# the following is NOT legal:	214	# the following is NOT legal:
125	$ber->[BER_CLASS] = ASN_PRIVATE; # ERROR, CLASS/TAG/CONSTRUCTED are READ ONLY(!)	215	$ber->[BER_CLASS] = ASN_PRIVATE; # ERROR, CLASS/TAG/FLAGS are READ ONLY(!)
126		216
127	# but all of the following are fine:	217	# but all of the following are fine:
128	$ber->[BER_DATA] = "string";	218	$ber->[BER_DATA] = "string";
129	$ber->[BER_DATA] = [ASN_UNIVERSAL, ASN_INTEGER32, 0, 123];	219	$ber->[BER_DATA] = [ASN_UNIVERSAL, ASN_INTEGER, 0, 123];
130	@$ber = (ASN_APPLICATION, SNMP_TIMETICKS, 0, 1000);	220	@$ber = (ASN_APPLICATION, SNMP_TIMETICKS, 0, 1000);
131		221
132	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
133	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
134	implementations, the C<ASN_APPLICATION> namespace which defines tags for	224	implementations, the C<ASN_APPLICATION> namespace which defines tags for
135	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
136	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.
137	for C<CHOICE>) and a private namespace (C<ASN_PRIVATE>).	227	for C<CHOICE>) and a private namespace (C<ASN_PRIVATE>).
138		228
139	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
140	(partial) interpretation of the data value. For example, right now, SNMP	230	(partial) interpretation of the data value. For example, SNMP defines
141	application namespace knowledge ix hardcoded into this module, so it	231	extra tags in the C<ASN_APPLICATION> namespace, and to take full advantage
142	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.
143	integers.
144		233
145	The most common tags in the C<ASN_UNIVERSAL> namespace are	234	The most common tags in the C<ASN_UNIVERSAL> namespace are
146	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>,
147	C<ASN_OBJECT_IDENTIFIER>, C<ASN_SEQUENCE>, C<ASN_SET> and	236	C<ASN_OBJECT_IDENTIFIER>, C<ASN_SEQUENCE>, C<ASN_SET> and
148	C<ASN_IA5_STRING>.	237	C<ASN_IA5_STRING>.
149		238
150	The most common tags in SNMP's C<ASN_APPLICATION> namespace	239	The most common tags in SNMP's C<ASN_APPLICATION> namespace are
151	are C<SNMP_IPADDRESS>, C<SNMP_COUNTER32>, C<SNMP_UNSIGNED32>,	240	C<SNMP_COUNTER32>, C<SNMP_UNSIGNED32>, C<SNMP_TIMETICKS> and
152	C<SNMP_TIMETICKS>, C<SNMP_OPAQUE> and C<SNMP_COUNTER64>.	241	C<SNMP_COUNTER64>.
153		242
154	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
155	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
156	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>,
157	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
158	en-/decode as BER tuples themselves.	247	subvalues which this module will en-/decode as BER tuples themselves.
159		248
160	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
161	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
162	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
163	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
164	interpret the namespace/tag.	253	interpret the namespace/tag.
165		254
166	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
167	string in place of some nice decoded value.	256	string in place of some nice decoded value.
168		257
…		…
170		259
171	=head2 DECODING AND ENCODING	260	=head2 DECODING AND ENCODING
172		261
173	=over	262	=over
174		263
175	=item $tuple = ber_decoded $bindata	264	=item $tuple = ber_decode $bindata[, $profile]
176		265
177	Decodes binary BER data in C<$bindata> and returns the resulting BER	266	Decodes binary BER data in C<$bindata> and returns the resulting BER
178	tuple. Croaks on any decoding error, so the returned C<$tuple> is always	267	tuple. Croaks on any decoding error, so the returned C<$tuple> is always
179	valid.	268	valid.
180		269
		270	How tags are interpreted is defined by the second argument, which must
		271	be a C<Convert::BER::XS::Profile> object. If it is missing, the default
		272	profile will be used (C<$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
181	=item $bindata = ber_encode $tuple	299	=item $bindata = ber_encode $tuple[, $profile]
182		300
183	Encodes the BER tuple into a BER/DER data structure.	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).
184		306
185	=back	307	=back
186		308
187	=head2 HELPER FUNCTIONS	309	=head2 HELPER FUNCTIONS
188		310
189	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>
190	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
191	functions, both to match BER tuples and to conmstruct BER tuples:	313	functions, both to match BER tuples and to construct BER tuples:
192		314
193	=head3 MATCH HELPERS	315	=head3 MATCH HELPERS
194		316
195	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
196	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
197	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.
198		320
199	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
200	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
201	tuple reference. in which case they silently fail to match.	323	tuple reference, in which case they silently fail to match.
202		324
203	=over	325	=over
204		326
205	=item $bool = ber_is $tuple, $class, $tag, $constructed, $data	327	=item $bool = ber_is $tuple, $class, $tag, $flags, $data
206		328
207	This takes a BER C<$tuple> and matches its elements agains the privded	329	This takes a BER C<$tuple> and matches its elements against the provided
208	values, all of which are optional - values that are either missing or	330	values, all of which are optional - values that are either missing or
209	C<undef> will be ignored, the others will be matched exactly (e.g. as if	331	C<undef> will be ignored, the others will be matched exactly (e.g. as if
210	you used C<==> or C<eq> (for C<$data>)).	332	you used C<==> or C<eq> (for C<$data>)).
211		333
212	Some examples:	334	Some examples:
…		…
215	orf die "tuple is not an ASN SEQUENCE";	337	orf die "tuple is not an ASN SEQUENCE";
216		338
217	ber_is $tuple, ASN_UNIVERSAL, ASN_NULL	339	ber_is $tuple, ASN_UNIVERSAL, ASN_NULL
218	or die "tuple is not an ASN NULL value";	340	or die "tuple is not an ASN NULL value";
219		341
220	ber_is $tuple, ASN_UNIVERSAL, ASN_INTEGER32, 0, 50	342	ber_is $tuple, ASN_UNIVERSAL, ASN_INTEGER, 0, 50
221	or die "BER integer must be 50";	343	or die "BER integer must be 50";
222		344
223	=item $seq = ber_is_seq $tuple	345	=item $seq = ber_is_seq $tuple
224		346
225	Returns the sequence members (the array of subvalues) if the C<$tuple> is	347	Returns the sequence members (the array of subvalues) if the C<$tuple> is
…		…
232	my $snmp = ber_is_seq $ber	354	my $snmp = ber_is_seq $ber
233	or die "SNMP packet invalid: does not start with SEQUENCE";	355	or die "SNMP packet invalid: does not start with SEQUENCE";
234		356
235	# 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
236		358
237	my $version = ber_is_i32 $snmp->[0]	359	my $version = ber_is_int $snmp->[0]
238	or die "SNMP packet invalid: does not start with version number";	360	or die "SNMP packet invalid: does not start with version number";
239		361
240	=item $bool = ber_is_i32 $tuple, $i32	362	=item $bool = ber_is_int $tuple, $int
241		363
242	Returns a true value if the C<$tuple> represents an ASN INTEGER32 with	364	Returns a true value if the C<$tuple> represents an ASN INTEGER with
243	the value C<$i32>.	365	the value C<$int>.
244		366
245	=item $i32 = ber_is_i32 $tuple	367	=item $int = ber_is_int $tuple
246		368
247	Returns true (and extracts the integer value) if the C<$tuple> is an ASN	369	Returns true (and extracts the integer value) if the C<$tuple> is an
248	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
249	true.	371	but true.
250		372
251	=item $bool = ber_is_oid $tuple, $oid_string	373	=item $bool = ber_is_oid $tuple, $oid_string
252		374
253	Returns true if the C<$tuple> represents an ASN_OBJECT_IDENTIFIER	375	Returns true if the C<$tuple> represents an ASN_OBJECT_IDENTIFIER
254	that exactly matches C<$oid_string>. Example:	376	that exactly matches C<$oid_string>. Example:
…		…
265		387
266	=head3 CONSTRUCTION HELPERS	388	=head3 CONSTRUCTION HELPERS
267		389
268	=over	390	=over
269		391
270	=item $tuple = ber_i32 $value	392	=item $tuple = ber_int $value
271		393
272	Constructs a new C<ASN_INTEGER32> tuple.	394	Constructs a new C<ASN_INTEGER> tuple.
273		395
274	=back	396	=back
275		397
276	=head2 RELATIONSHIP TO L<Convert::BER> and L<Convert::ASN1>	398	=head2 RELATIONSHIP TO L<Convert::BER> and L<Convert::ASN1>
277		399
…		…
287	use common::sense;	409	use common::sense;
288		410
289	use XSLoader ();	411	use XSLoader ();
290	use Exporter qw(import);	412	use Exporter qw(import);
291		413
292	our $VERSION = 0.2;	414	our $VERSION;
293		415
		416	BEGIN {
		417	$VERSION = '1.0';
294	XSLoader::load __PACKAGE__, $VERSION;	418	XSLoader::load __PACKAGE__, $VERSION;
		419	}
295		420
296	our %EXPORT_TAGS = (	421	our %EXPORT_TAGS = (
		422	const_index => [qw(
		423	BER_CLASS BER_TAG BER_FLAGS BER_DATA
		424	)],
		425	const_asn_class => [qw(
		426	ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE
		427	)],
		428	const_asn_tag => [qw(
		429	ASN_BOOLEAN ASN_INTEGER ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OID ASN_OBJECT_IDENTIFIER
		430	ASN_OBJECT_DESCRIPTOR ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED
		431	ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING
		432	ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING
		433	ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING
		434	ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING
		435	)],
		436	const_ber_type => [qw(
		437	BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT
		438	BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL
		439	BER_TYPE_IPADDRESS BER_TYPE_CROAK
		440	)],
297	const => [qw(	441	const_snmp => [qw(
298	BER_CLASS BER_TAG BER_CONSTRUCTED BER_DATA	442	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_GAUGE32 SNMP_UNSIGNED32
299		443	SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
300	ASN_BOOLEAN ASN_INTEGER32 ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER ASN_TAG_BER ASN_TAG_MASK	444	)],
301	ASN_CONSTRUCTED ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE ASN_CLASS_MASK ASN_CLASS_SHIFT	445	decode => [qw(
302	ASN_SEQUENCE	446	ber_decode ber_decode_prefix
303		447	ber_is ber_is_seq ber_is_int ber_is_oid
304	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64	448	ber_dump
305	)],	449	)],
306	encode => [qw(	450	encode => [qw(
307	ber_decode
308	ber_is ber_is_seq ber_is_i32 ber_is_oid
309	)],
310	decode => [qw(
311	ber_encode	451	ber_encode
		452	ber_int
312	)],	453	)],
313	);	454	);
314		455
315	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;	456	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;
316		457
317	$EXPORT_TAGS{all} = \@EXPORT_OK;	458	$EXPORT_TAGS{all} = \@EXPORT_OK;
		459	$EXPORT_TAGS{const_asn} = [map @{ $EXPORT_TAGS{$_} }, qw(const_asn_class const_asn_tag)];
		460	$EXPORT_TAGS{const} = [map @{ $EXPORT_TAGS{$_} }, qw(const_index const_asn)];
318		461
319	1;	462	our $DEFAULT_PROFILE = new Convert::BER::XS::Profile;
320		463
321	=head2 BUGS / SHORTCOMINGs	464	$DEFAULT_PROFILE->_set_default;
322		465
323	This module does have a number of SNMPisms hardcoded, such as the SNMP	466	# additional SNMP application types
324	tags for Unsigned32 and so on. More configurability is needed, and, if	467	our $SNMP_PROFILE = new Convert::BER::XS::Profile;
325	ever implemented, will come in a form similar to how L<JSON::XS> and	468
326	L<CBOR::XS> respresent things, namely with an object-oriented interface.	469	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS);
		470	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT);
		471	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT);
		472	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT);
		473	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_IPADDRESS);
		474
		475	=head2 DEBUGGING
		476
		477	To aid debugging, you cna call the C<ber_dump> function to print a "nice"
		478	representation to STDOUT.
		479
		480	=over
		481
		482	=item ber_dump $tuple[, $profile[, $prefix]]
		483
		484	In addition to specifying the BER C<$tuple> to dump, youc an also specify
		485	a C<$profile> and a C<$prefix> string that is printed in front of each line.
		486
		487	If C<$profile> is C<$Convert::BER::XS::SNMP_PROFILE>, then C<ber_dump>
		488	will try to improve its output for SNMP data.
		489
		490	The output usually contains three columns, the "human readable" tag, the
		491	BER type used to decode it, and the data value.
		492
		493	This function is somewhat slow and uses a number of heuristics and tricks,
		494	so it really is only suitable for debug prints.
		495
		496	Example output:
		497
		498	SEQUENCE
		499	\| OCTET_STRING bytes 800063784300454045045400000001
		500	\| OCTET_STRING bytes
		501	\| CONTEXT (7) bytes CONSTRUCTED
		502	\| \| INTEGER int 1058588941
		503	\| \| INTEGER int 0
		504	\| \| INTEGER int 0
		505	\| \| SEQUENCE
		506	\| \| \| SEQUENCE
		507	\| \| \| \| OID oid 1.3.6.1.2.1.1.3.0
		508	\| \| \| \| TIMETICKS int 638085796
		509
		510	=cut
		511
		512	# reverse enum, very slow and ugly hack
		513	sub _re {
		514	my ($export_tag, $value) = @_;
		515
		516	for my $symbol (@{ $EXPORT_TAGS{$export_tag} }) {
		517	$value == eval $symbol
		518	and return $symbol;
		519	}
		520
		521	"($value)"
		522	}
		523
		524	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT);
		525
		526	sub _ber_dump {
		527	my ($ber, $profile, $indent) = @_;
		528
		529	if (my $seq = ber_is_seq $ber) {
		530	printf "%sSEQUENCE\n", $indent;
		531	&_ber_dump ($_, $profile, "$indent\| ")
		532	for @$seq;
		533	} else {
		534	my $asn = $ber->[BER_CLASS] == ASN_UNIVERSAL;
		535
		536	my $class = _re const_asn_class => $ber->[BER_CLASS];
		537	my $tag = $asn ? _re const_asn_tag => $ber->[BER_TAG] : $ber->[BER_TAG];
		538	my $type = _re const_ber_type => $profile->get ($ber->[BER_CLASS], $ber->[BER_TAG]);
		539	my $data = $ber->[BER_DATA];
		540
		541	if ($profile == $SNMP_PROFILE and $ber->[BER_CLASS] == ASN_APPLICATION) {
		542	$tag = _re const_snmp => $ber->[BER_TAG];
		543	} elsif (!$asn) {
		544	$tag = "$class ($tag)";
		545	}
		546
		547	$class =~ s/^ASN_//;
		548	$tag =~ s/^(ASN_\|SNMP_)//;
		549	$type =~ s/^BER_TYPE_//;
		550
		551	if ($ber->[BER_FLAGS]) {
		552	printf "$indent%-16.16s %-6.6s CONSTRUCTED\n", $tag, lc $type;
		553	&_ber_dump ($_, $profile, "$indent\| ")
		554	for @$data;
		555	} else {
		556	if ($data =~ y/\x20-\x7e//c / (length $data \|\| 1) > 0.2 or $data =~ /\x00./s) {
		557	# assume binary
		558	$data = unpack "H*", $data;
		559	substr $data, 40, 1e9, "..." if 40 < length $data;
		560	} else {
		561	$data =~ s/[^\x20-\x7e]/./g;
		562	$data = "\"$data\"" if $type =~ /string/i;
		563	substr $data, 40, 1e9, "..." if 40 < length $data;
		564	}
		565
		566	printf "$indent%-16.16s %-6.6s %s\n", $tag, lc $type, $data;
		567	}
		568	}
		569	}
		570
		571	sub ber_dump($;$$) {
		572	_ber_dump $_[0], $_[1] \|\| $DEFAULT_PROFILE, $_[2];
		573	}
		574
		575	=head1 PROFILES
		576
		577	While any BER data can be correctly encoded and decoded out of the box, it
		578	can be inconvenient to have to manually decode some values into a "better"
		579	format: for instance, SNMP TimeTicks values are decoded into the raw octet
		580	strings of their BER representation, which is quite hard to decode. With
		581	profiles, you can change which class/tag combinations map to which decoder
		582	function inside C<ber_decode> (and of course also which encoder functions
		583	are used in C<ber_encode>).
		584
		585	This works by mapping specific class/tag combinations to an internal "ber
		586	type".
		587
		588	The default profile supports the standard ASN.1 types, but no
		589	application-specific ones. This means that class/tag combinations not in
		590	the base set of ASN.1 are decoded into their raw octet strings.
		591
		592	C<Convert::BER::XS> defines two profile variables you can use out of the box:
		593
		594	=over
		595
		596	=item C<$Convert::BER::XS::DEFAULT_PROFILE>
		597
		598	This is the default profile, i.e. the profile that is used when no
		599	profile is specified for de-/encoding.
		600
		601	You can modify it, but remember that this modifies the defaults for all
		602	callers that rely on the default profile.
		603
		604	=item C<$Convert::BER::XS::SNMP_PROFILE>
		605
		606	A profile with mappings for SNMP-specific application tags added. This is
		607	useful when de-/encoding SNMP data.
		608
		609	Example:
		610
		611	$ber = ber_decode $data, $Convert::BER::XS::SNMP_PROFILE;
		612
		613	=back
		614
		615	=head2 The Convert::BER::XS::Profile class
		616
		617	=over
		618
		619	=item $profile = new Convert::BER::XS::Profile
		620
		621	Create a new profile. The profile will be identical to the default
		622	profile.
		623
		624	=item $profile->set ($class, $tag, $type)
		625
		626	Sets the mapping for the given C<$class>/C<$tag> combination to C<$type>,
		627	which must be one of the C<BER_TYPE_*> constants.
		628
		629	Note that currently, the mapping is stored in a flat array, so large
		630	values of C<$tag> will consume large amounts of memory.
		631
		632	Example:
		633
		634	$profile = new Convert::BER::XS::Profile;
		635	$profile->set (ASN_APPLICATION, SNMP_COUNTER32, BER_TYPE_INT);
		636	$ber = ber_decode $data, $profile;
		637
		638	=item $type = $profile->get ($class, $tag)
		639
		640	Returns the BER type mapped to the given C<$class>/C<$tag> combination.
		641
		642	=back
		643
		644	=head2 BER TYPES
		645
		646	This lists the predefined BER types - you can map any C<CLASS>/C<TAG>
		647	combination to any C<BER_TYPE_*>.
		648
		649	=over
		650
		651	=item C<BER_TYPE_BYTES>
		652
		653	The raw octets of the value. This is the default type for unknown tags and
		654	de-/encodes the value as if it were an octet string, i.e. by copying the
		655	raw bytes.
		656
		657	=item C<BER_TYPE_UTF8>
		658
		659	Like C<BER_TYPE_BYTES>, but decodes the value as if it were a UTF-8 string
		660	(without validation!) and encodes a perl unicode string into a UTF-8 BER
		661	string.
		662
		663	=item C<BER_TYPE_UCS2>
		664
		665	Similar to C<BER_TYPE_UTF8>, but treats the BER value as UCS-2 encoded
		666	string.
		667
		668	=item C<BER_TYPE_UCS4>
		669
		670	Similar to C<BER_TYPE_UTF8>, but treats the BER value as UCS-4 encoded
		671	string.
		672
		673	=item C<BER_TYPE_INT>
		674
		675	Encodes and decodes a BER integer value to a perl integer scalar. This
		676	should correctly handle 64 bit signed and unsigned values.
		677
		678	=item C<BER_TYPE_OID>
		679
		680	Encodes and decodes an OBJECT IDENTIFIER into dotted form without leading
		681	dot, e.g. C<1.3.6.1.213>.
		682
		683	=item C<BER_TYPE_RELOID>
		684
		685	Same as C<BER_TYPE_OID> but uses relative object identifier
		686	encoding: ASN.1 has this hack of encoding the first two OID components
		687	into a single integer in a weird attempt to save an insignificant amount
		688	of space in an otherwise wasteful encoding, and relative OIDs are
		689	basically OIDs without this hack. The practical difference is that the
		690	second component of an OID can only have the values 1..40, while relative
		691	OIDs do not have this restriction.
		692
		693	=item C<BER_TYPE_NULL>
		694
		695	Decodes an C<ASN_NULL> value into C<undef>, and always encodes a
		696	C<ASN_NULL> type, regardless of the perl value.
		697
		698	=item C<BER_TYPE_BOOL>
		699
		700	Decodes an C<ASN_BOOLEAN> value into C<0> or C<1>, and encodes a perl
		701	boolean value into an C<ASN_BOOLEAN>.
		702
		703	=item C<BER_TYPE_REAL>
		704
		705	Decodes/encodes a BER real value. NOT IMPLEMENTED.
		706
		707	=item C<BER_TYPE_IPADDRESS>
		708
		709	Decodes/encodes a four byte string into an IPv4 dotted-quad address string
		710	in Perl. Given the obsolete nature of this type, this is a low-effort
		711	implementation that simply uses C<sprintf> and C<sscanf>-style conversion,
		712	so it won't handle all string forms supported by C<inet_aton> for example.
		713
		714	=item C<BER_TYPE_CROAK>
		715
		716	Always croaks when encountered during encoding or decoding - the
		717	default behaviour when encountering an unknown type is to treat it as
		718	C<BER_TYPE_BYTES>. When you don't want that but instead prefer a hard
		719	error for some types, then C<BER_TYPE_CROAK> is for you.
		720
		721	=back
		722
		723	=head2 Example Profile
		724
		725	The following creates a profile suitable for SNMP - it's exactly identical
		726	to the C<$Convert::BER::XS::SNMP_PROFILE> profile.
		727
		728	our $SNMP_PROFILE = new Convert::BER::XS::Profile;
		729
		730	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS);
		731	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT);
		732	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT);
		733	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT);
		734	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_IPADDRESS);
		735	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT);
		736
		737	=head2 LIMITATIONS/NOTES
		738
		739	This module can only en-/decode 64 bit signed and unsigned integers, and
		740	only when your perl supports those.
		741
		742	This module does not generally care about ranges, i.e. it will happily
		743	de-/encode 64 bit integers into an C<ASN_INTEGER> value, or a negative
		744	number into an C<SNMP_COUNTER64>.
		745
		746	OBJECT IDENTIFIEERs cannot have unlimited length, although the limit is
		747	much larger than e.g. the one imposed by SNMP or other protocols,a nd is
		748	about 4kB.
		749
		750	Indefinite length encoding is not supported.
		751
		752	Constructed strings are decoded just fine, but there should be a way to
		753	join them for convenience.
		754
		755	REAL values are not supported and will currently croak.
		756
		757	The encoder and decoder tend to accept more formats than should be
		758	strictly supported.
		759
		760	This module has undergone little to no testing so far.
		761
		762	=head2 ITHREADS SUPPORT
		763
		764	This module is unlikely to work when the (officially discouraged) ithreads
		765	are in use.
327		766
328	=head1 AUTHOR	767	=head1 AUTHOR
329		768
330	Marc Lehmann <schmorp@schmorp.de>	769	Marc Lehmann <schmorp@schmorp.de>
331	http://software.schmorp.de/pkg/Convert-BER-XS	770	http://software.schmorp.de/pkg/Convert-BER-XS
332		771
333	=cut	772	=cut
334		773
		774	1;
		775

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Comparing Convert-BER-XS/XS.pm (file contents): Revision 1.12 by root, Fri Apr 19 21:24:31 2019 UTC vs. Revision 1.40 by root, Sun Apr 21 00:42:15 2019 UTC

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Comparing Convert-BER-XS/XS.pm (file contents):
Revision 1.12 by root, Fri Apr 19 21:24:31 2019 UTC vs.
Revision 1.40 by root, Sun Apr 21 00:42:15 2019 UTC