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

Comparing Convert-BER-XS/XS.pm (file contents):
Revision 1.11 by root, Fri Apr 19 20:44:34 2019 UTC vs.
Revision 1.35 by root, Sat Apr 20 21:51:40 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" ],
…		…
40	# let's decode it a bit with some helper functions	42	# let's decode it a bit with some helper functions
41		43
42	my $msg = ber_is_seq $ber	44	my $msg = ber_is_seq $ber
43	or die "SNMP message does not start with a sequence";	45	or die "SNMP message does not start with a sequence";
44		46
45	ber_is $msg->[0], ASN_UNIVERSAL, ASN_INTEGER32, 0	47	ber_is $msg->[0], ASN_UNIVERSAL, ASN_INTEGER, 0
46	or die "SNMP message does not start with snmp version\n";	48	or die "SNMP message does not start with snmp version\n";
47		49
48	# message is SNMP v1 or v2c?	50	# message is SNMP v1 or v2c?
49	if ($msg->[0][BER_DATA] == 0 \|\| $msg->[0][BER_DATA] == 1) {	51	if ($msg->[0][BER_DATA] == 0 \|\| $msg->[0][BER_DATA] == 1) {
50		52
…		…
53	my $trap = $msg->[2][BER_DATA];	55	my $trap = $msg->[2][BER_DATA];
54		56
55	# check whether trap is a cisco mac notification mac changed message	57	# check whether trap is a cisco mac notification mac changed message
56	if (	58	if (
57	(ber_is_oid $trap->[0], "1.3.6.1.4.1.9.9.215.2") # cmnInterfaceObjects	59	(ber_is_oid $trap->[0], "1.3.6.1.4.1.9.9.215.2") # cmnInterfaceObjects
58	and (ber_is_i32 $trap->[2], 6)	60	and (ber_is_int $trap->[2], 6)
59	and (ber_is_i32 $trap->[3], 1) # mac changed msg	61	and (ber_is_int $trap->[3], 1) # mac changed msg
60	) {	62	) {
61	... and so on	63	... and so on
62		64
63	# finally, let's encode it again and hope it results in the same bit pattern	65	# finally, let's encode it again and hope it results in the same bit pattern
64		66
65	my $buf = ber_encode $ber;	67	my $buf = ber_encode $ber, $Convert::BER::XS::SNMP_PROFILE;
66		68
67	=head1 DESCRIPTION	69	=head1 DESCRIPTION
68		70
69	WARNING: Before release 1.0, the API is not considered stable in any way.	71	WARNING: Before release 1.0, the API is not considered stable in any way.
70		72
71	This module implements a I<very> low level BER/DER en-/decoder.	73	This module implements a I<very> low level BER/DER en-/decoder.
72		74
73	If is tuned for low memory and high speed, while still maintaining some	75	It is tuned for low memory and high speed, while still maintaining some
74	level of user-friendlyness.	76	level of user-friendlyness.
75		77
76	Currently, not much is documented, as this is an initial release to	78	=head2 EXPORT TAGS AND CONSTANTS
77	reserve CPAN namespace, stay tuned for a few days.	79
		80	By default this module doesn't export any symbols, but if you don't want
		81	to break your keyboard, editor or eyesight with extremely long names, I
		82	recommend importing the C<:all> tag. Still, you can selectively import
		83	things.
		84
		85	=over
		86
		87	=item C<:all>
		88
		89	All of the below. Really. Recommended for at least first steps, or if you
		90	don't care about a few kilobytes of wasted memory (and namespace).
		91
		92	=item C<:const>
		93
		94	All of the strictly ASN.1-related constants defined by this module, the
		95	same as C<:const_asn :const_index>. Notably, this does not contain
		96	C<:const_ber_type> and C<:const_snmp>.
		97
		98	A good set to get everything you need to decode and match BER data would be
		99	C<:decode :const>.
		100
		101	=item C<:const_index>
		102
		103	The BER tuple array index constants:
		104
		105	BER_CLASS BER_TAG BER_FLAGS BER_DATA
		106
		107	=item C<:const_asn>
		108
		109	ASN class values (these are C<0>, C<1>, C<2> and C<3>, respectively -
		110	exactly thw two topmost bits from the identifier octet shifted 6 bits to
		111	the right):
		112
		113	ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE
		114
		115	ASN tag values (some of which are aliases, such as C<ASN_OID>). Their
		116	numerical value corresponds exactly to the numbers used in BER/X.690.
		117
		118	ASN_BOOLEAN ASN_INTEGER ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER
		119	ASN_OBJECT_DESCRIPTOR ASN_OID ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED
		120	ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING
		121	ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING
		122	ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING
		123	ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING
		124
		125	=item C<:const_ber_type>
		126
		127	The BER type constants, explained in the PROFILES section.
		128
		129	BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT
		130	BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL
		131	BER_TYPE_IPADDRESS BER_TYPE_CROAK
		132
		133	=item C<:const_snmp>
		134
		135	Constants only relevant to SNMP. These are the tag values used by SNMP in
		136	the C<ASN_APPLICATION> namespace and have the exact numerical value as in
		137	BER/RFC 2578.
		138
		139	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_GAUGE32
		140	SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
		141
		142	=item C<:decode>
		143
		144	C<ber_decode> and the match helper functions:
		145
		146	ber_decode ber-decode_prefix
		147	ber_is ber_is_seq ber_is_int ber_is_oid
		148
		149	=item C<:encode>
		150
		151	C<ber_encode> and the construction helper functions:
		152
		153	ber_encode
		154	ber_int
		155
		156	=back
78		157
79	=head2 ASN.1/BER/DER/... BASICS	158	=head2 ASN.1/BER/DER/... BASICS
80		159
81	ASN.1 is a strange language that can be sed to describe protocols and	160	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	161	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	162	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.	163	of this module, and is used in SNMP, LDAP or X.509 for example.
85		164
86	While ASN.1 defines a schema that is useful to interpret encoded data,	165	While ASN.1 defines a schema that is useful to interpret encoded data,
87	the BER encoding is actually somehat self-describing: you might not know	166	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,	167	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	168	but you can nevertheless decode the overall structure, even if you end up
90	with just a binary blob for the actual value.	169	with just a binary blob for the actual value.
91		170
92	This works because BER values are tagged with a type and a namespace,	171	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	172	and also have a flag that says whether a value consists of subvalues (is
94	"constructed") or not (is "primitive").	173	"constructed") or not (is "primitive").
95		174
96	Tags are simple integers, and ASN.1 defines a somewhat weird assortment of	175	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	176	of those - for example, you have one integers and 16(!) different
98	string types, but there is no unsigned32 type for example. Different	177	string types, but there is no Unsigned32 type for example. Different
99	applications work around this in different ways, for example, SNMP defines	178	applications work around this in different ways, for example, SNMP defines
100	application-specific Gauge32, Counter32 and Unsigned32, which are mapped	179	application-specific Gauge32, Counter32 and Unsigned32, which are mapped
101	to two different tags: you can distinguish between Counter32 and the	180	to two different tags: you can distinguish between Counter32 and the
102	others, but not between Gause32 and Unsigned32, without the ASN.1 schema.	181	others, but not between Gause32 and Unsigned32, without the ASN.1 schema.
103		182
…		…
106	=head2 DECODED BER REPRESENTATION	185	=head2 DECODED BER REPRESENTATION
107		186
108	This module represents every BER value as a 4-element tuple (actually an	187	This module represents every BER value as a 4-element tuple (actually an
109	array-reference):	188	array-reference):
110		189
111	[CLASS, TAG, CONSTRUCTED, DATA]	190	[CLASS, TAG, FLAGS, DATA]
		191
		192	For example:
		193
		194	[ASN_UNIVERSAL, ASN_INTEGER, 0, 177] # the integer 177
		195	[ASN_UNIVERSAL, ASN_OCTET_STRING, 0, "john"] # the string "john"
		196	[ASN_UNIVERSAL, ASN_OID, 0, "1.3.6.133"] # some OID
		197	[ASN_UNIVERSAL, ASN_SEQUENCE, 1, [ [ASN_UNIVERSAL... # a sequence
112		198
113	To avoid non-descriptive hardcoded array index numbers, this module	199	To avoid non-descriptive hardcoded array index numbers, this module
114	defines symbolic constants to access these members: C<BER_CLASS>,	200	defines symbolic constants to access these members: C<BER_CLASS>,
115	C<BER_TAG>, C<BER_CONSTRUCTED> and C<BER_DATA>.	201	C<BER_TAG>, C<BER_FLAGS> and C<BER_DATA>.
116		202
117	Also, the first three members are integers with a little caveat: for	203	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	204	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	205	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.:	206	I<DATA> member, and you may re-assign the array itself, e.g.:
121		207
122	$ber = ber_decode $binbuf;	208	$ber = ber_decode $binbuf;
123		209
124	# the following is NOT legal:	210	# the following is NOT legal:
125	$ber->[BER_CLASS] = ASN_PRIVATE; # ERROR, CLASS/TAG/CONSTRUCTED are READ ONLY(!)	211	$ber->[BER_CLASS] = ASN_PRIVATE; # ERROR, CLASS/TAG/FLAGS are READ ONLY(!)
126		212
127	# but all of the following are fine:	213	# but all of the following are fine:
128	$ber->[BER_DATA] = "string";	214	$ber->[BER_DATA] = "string";
129	$ber->[BER_DATA] = [ASN_UNIVERSAL, ASN_INTEGER32, 0, 123];	215	$ber->[BER_DATA] = [ASN_UNIVERSAL, ASN_INTEGER, 0, 123];
130	@$ber = (ASN_APPLICATION, SNMP_TIMETICKS, 0, 1000);	216	@$ber = (ASN_APPLICATION, SNMP_TIMETICKS, 0, 1000);
131		217
132	I<CLASS> is something like a namespace for I<TAG>s - there is the	218	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	219	C<ASN_UNIVERSAL> namespace which defines tags common to all ASN.1
134	implementations, the C<ASN_APPLICATION> namespace which defines tags for	220	implementations, the C<ASN_APPLICATION> namespace which defines tags for
135	specific applications (for example, the SNMP C<Unsigned32> type is in this	221	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.	222	namespace), a special-purpose context namespace (C<ASN_CONTEXT>, used e.g.
137	for C<CHOICE>) and a private namespace (C<ASN_PRIVATE>).	223	for C<CHOICE>) and a private namespace (C<ASN_PRIVATE>).
138		224
139	The meaning of the I<TAG> depends on the namespace, and defines a	225	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	226	(partial) interpretation of the data value. For example, SNMP defines
141	application namespace knowledge ix hardcoded into this module, so it	227	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	228	of these, you need to tell this module how to handle those via profiles.
143	integers.
144		229
145	The most common tags in the C<ASN_UNIVERSAL> namespace are	230	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>,	231	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	232	C<ASN_OBJECT_IDENTIFIER>, C<ASN_SEQUENCE>, C<ASN_SET> and
148	C<ASN_IA5_STRING>.	233	C<ASN_IA5_STRING>.
149		234
150	The most common tags in SNMP's C<ASN_APPLICATION> namespace	235	The most common tags in SNMP's C<ASN_APPLICATION> namespace are
151	are C<SNMP_IPADDRESS>, C<SNMP_COUNTER32>, C<SNMP_UNSIGNED32>,	236	C<SNMP_COUNTER32>, C<SNMP_UNSIGNED32>, C<SNMP_TIMETICKS> and
152	C<SNMP_TIMETICKS>, C<SNMP_OPAQUE> and C<SNMP_COUNTER64>.	237	C<SNMP_COUNTER64>.
153		238
154	The I<CONSTRUCTED> flag is really just a boolean - if it is false, the	239	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	240	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"	241	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	242	then the value is "constructed" which just means it contains a list of
158	en-/decode as BER tuples themselves.	243	subvalues which this module will en-/decode as BER tuples themselves.
159		244
160	The I<DATA> value is either a reference to an array of further tuples (if	245	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,	246	(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)	247	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	248	a binary string with the raw octets if this module doesn't know how to
164	interpret the namespace/tag.	249	interpret the namespace/tag.
165		250
166	Thus, you can always decode a BER data structure and at worst you get a	251	Thus, you can always decode a BER data structure and at worst you get a
167	string in place of some nice decoded value.	252	string in place of some nice decoded value.
168		253
…		…
170		255
171	=head2 DECODING AND ENCODING	256	=head2 DECODING AND ENCODING
172		257
173	=over	258	=over
174		259
175	=item $tuple = ber_decoded $bindata	260	=item $tuple = ber_decode $bindata[, $profile]
176		261
177	Decodes binary BER data in C<$bindata> and returns the resulting BER	262	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	263	tuple. Croaks on any decoding error, so the returned C<$tuple> is always
179	valid.	264	valid.
180		265
		266	How tags are interpreted is defined by the second argument, which must
		267	be a C<Convert::BER::XS::Profile> object. If it is missing, the default
		268	profile will be used (C<$Convert::BER::XS::DEFAULT_PROFILE>).
		269
		270	In addition to rolling your own, this module provides a
		271	C<$Convert::BER::XS::SNMP_PROFILE> that knows about the additional SNMP
		272	types.
		273
		274	Example: decode a BER blob using the default profile - SNMP values will be
		275	decided as raw strings.
		276
		277	$tuple = ber_decode $data;
		278
		279	Example: as above, but use the provided SNMP profile.
		280
		281	$tuple = ber_encode $data, $Convert::BER::XS::SNMP_PROFILE;
		282
		283	=item ($tuple, $bytes) = ber_decode_prefix $bindata[, $profile]
		284
		285	Works like C<ber_decode>, except it doesn't croak when there is data after
		286	the BER data, but instead returns the decoded value and the number of
		287	bytes it decoded.
		288
		289	This is useful when you have BER data at the start of a buffer and other
		290	data after, and you need to find the length.
		291
		292	Also, since BER is self-delimited, this can be used to decode multiple BER
		293	values joined together.
		294
181	=item $bindata = ber_encode $tuple	295	=item $bindata = ber_encode $tuple[, $profile]
182		296
183	Encodes the BER tuple into a BER/DER data structure.	297	Encodes the BER tuple into a BER/DER data structure. AS with
		298	Cyber_decode>, an optional profile can be given.
		299
		300	The encoded data should be both BER and DER ("shortest form") compliant
		301	unless the input says otherwise (e.g. it uses constructed strings).
184		302
185	=back	303	=back
186		304
187	=head2 HELPER FUNCTIONS	305	=head2 HELPER FUNCTIONS
188		306
189	Working with a 4-tuple for every value can be annoying. Or, rather, I<is>	307	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	308	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:	309	functions, both to match BER tuples and to construct BER tuples:
192		310
193	=head3 MATCH HELPERS	311	=head3 MATCH HELPERS
194		312
195	Thse functions accept a BER tuple as first argument and either paertially	313	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	314	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.	315	a value, and one which only matches the type and returns the value.
198		316
199	They do check whether valid tuples are passed in and croak otherwise. As	317	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	318	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.	319	tuple reference, in which case they silently fail to match.
202		320
203	=over	321	=over
204		322
205	=item $bool = ber_is $tuple, $class, $tag, $constructed, $data	323	=item $bool = ber_is $tuple, $class, $tag, $flags, $data
206		324
207	This takes a BER C<$tuple> and matches its elements agains the privded	325	This takes a BER C<$tuple> and matches its elements against the provided
208	values, all of which are optional - values that are either missing or	326	values, all of which are optional - values that are either missing or
209	C<undef> will be ignored, the others will be matched exactly (e.g. as if	327	C<undef> will be ignored, the others will be matched exactly (e.g. as if
210	you used C<==> or C<eq> (for C<$data>)).	328	you used C<==> or C<eq> (for C<$data>)).
211		329
212	Some examples:	330	Some examples:
…		…
215	orf die "tuple is not an ASN SEQUENCE";	333	orf die "tuple is not an ASN SEQUENCE";
216		334
217	ber_is $tuple, ASN_UNIVERSAL, ASN_NULL	335	ber_is $tuple, ASN_UNIVERSAL, ASN_NULL
218	or die "tuple is not an ASN NULL value";	336	or die "tuple is not an ASN NULL value";
219		337
220	ber_is $tuple, ASN_UNIVERSAL, ASN_INTEGER32, 0, 50	338	ber_is $tuple, ASN_UNIVERSAL, ASN_INTEGER, 0, 50
221	or die "BER integer must be 50";	339	or die "BER integer must be 50";
222		340
223	=item $seq = ber_is_seq $tuple	341	=item $seq = ber_is_seq $tuple
224		342
225	Returns the sequence members (the array of subvalues) if the C<$tuple> is	343	Returns the sequence members (the array of subvalues) if the C<$tuple> is
…		…
232	my $snmp = ber_is_seq $ber	350	my $snmp = ber_is_seq $ber
233	or die "SNMP packet invalid: does not start with SEQUENCE";	351	or die "SNMP packet invalid: does not start with SEQUENCE";
234		352
235	# now we know $snmp is a sequence, so decode the SNMP version	353	# now we know $snmp is a sequence, so decode the SNMP version
236		354
237	my $version = ber_is_i32 $snmp->[0]	355	my $version = ber_is_int $snmp->[0]
238	or die "SNMP packet invalid: does not start with version number";	356	or die "SNMP packet invalid: does not start with version number";
239		357
240	=item $bool = ber_is_i32 $tuple, $i32	358	=item $bool = ber_is_int $tuple, $int
241		359
242	Returns a true value if the C<$tuple> represents an ASN INTEGER32 with	360	Returns a true value if the C<$tuple> represents an ASN INTEGER with
243	the value C<$i32>.	361	the value C<$int>.
244		362
245	=item $i32 = ber_is_i32 $tuple	363	=item $int = ber_is_int $tuple
246		364
247	Returns true (and extracts the integer value) if the C<$tuple> is an ASN	365	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	366	C<ASN_INTEGER>. For C<0>, this function returns a special value that is 0
249	true.	367	but true.
250		368
251	=item $bool = ber_is_oid $tuple, $oid_string	369	=item $bool = ber_is_oid $tuple, $oid_string
252		370
253	Returns true if the C<$tuple> represents an ASN_OBJECT_IDENTIFIER	371	Returns true if the C<$tuple> represents an ASN_OBJECT_IDENTIFIER
254	that exactly matches C$oid_string>. Exmaple:	372	that exactly matches C<$oid_string>. Example:
255		373
256	ber_is_oid $tuple, "1.3.6.1.4"	374	ber_is_oid $tuple, "1.3.6.1.4"
257	or die "oid must be 1.3.6.1.4";	375	or die "oid must be 1.3.6.1.4";
258		376
259	=item $oid = ber_is_oid $tuple	377	=item $oid = ber_is_oid $tuple
…		…
265		383
266	=head3 CONSTRUCTION HELPERS	384	=head3 CONSTRUCTION HELPERS
267		385
268	=over	386	=over
269		387
270	=item $tuple = ber_i32 $value	388	=item $tuple = ber_int $value
271		389
272	Constructs a new C<ASN_INTEGER32> tuple.	390	Constructs a new C<ASN_INTEGER> tuple.
273		391
274	=back	392	=back
275		393
276	=head2 RELATIONSHIP TO L<Convert::BER> and L<Convert::ASN1>	394	=head2 RELATIONSHIP TO L<Convert::BER> and L<Convert::ASN1>
277		395
…		…
287	use common::sense;	405	use common::sense;
288		406
289	use XSLoader ();	407	use XSLoader ();
290	use Exporter qw(import);	408	use Exporter qw(import);
291		409
292	our $VERSION = 0.2;	410	our $VERSION;
293		411
		412	BEGIN {
		413	$VERSION = '1.0';
294	XSLoader::load __PACKAGE__, $VERSION;	414	XSLoader::load __PACKAGE__, $VERSION;
		415	}
295		416
296	our %EXPORT_TAGS = (	417	our %EXPORT_TAGS = (
		418	const_index => [qw(
		419	BER_CLASS BER_TAG BER_FLAGS BER_DATA
		420	)],
297	const => [qw(	421	const_asn => [qw(
298	BER_CLASS BER_TAG BER_CONSTRUCTED BER_DATA
299
300	ASN_BOOLEAN ASN_INTEGER32 ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER ASN_TAG_BER ASN_TAG_MASK	422	ASN_BOOLEAN ASN_INTEGER ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER
301	ASN_CONSTRUCTED ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE ASN_CLASS_MASK ASN_CLASS_SHIFT	423	ASN_OBJECT_DESCRIPTOR ASN_OID ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED
302	ASN_SEQUENCE	424	ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING
303		425	ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING
304	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64	426	ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING
		427	ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING
		428
		429	ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE
		430	)],
		431	const_ber_type => [qw(
		432	BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT
		433	BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL
		434	BER_TYPE_IPADDRESS BER_TYPE_CROAK
		435	)],
		436	const_snmp => [qw(
		437	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_GAUGE32 SNMP_UNSIGNED32
		438	SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
		439	)],
		440	decode => [qw(
		441	ber_decode ber_decode_prefix
		442	ber_is ber_is_seq ber_is_int ber_is_oid
305	)],	443	)],
306	encode => [qw(	444	encode => [qw(
307	ber_decode
308	ber_is ber_is_seq ber_is_i32 ber_is_oid
309	)],
310	decode => [qw(
311	ber_encode	445	ber_encode
		446	ber_int
312	)],	447	)],
313	);	448	);
314		449
315	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;	450	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;
316		451
317	$EXPORT_TAGS{all} = \@EXPORT_OK;	452	$EXPORT_TAGS{all} = \@EXPORT_OK;
		453	$EXPORT_TAGS{const} = [map @{ $EXPORT_TAGS{$_} }, qw(const_index const_asn)];
		454
		455	=head1 PROFILES
		456
		457	While any BER data can be correctly encoded and decoded out of the box, it
		458	can be inconvenient to have to manually decode some values into a "better"
		459	format: for instance, SNMP TimeTicks values are decoded into the raw octet
		460	strings of their BER representation, which is quite hard to decode. With
		461	profiles, you can change which class/tag combinations map to which decoder
		462	function inside C<ber_decode> (and of course also which encoder functions
		463	are used in C<ber_encode>).
		464
		465	This works by mapping specific class/tag combinations to an internal "ber
		466	type".
		467
		468	The default profile supports the standard ASN.1 types, but no
		469	application-specific ones. This means that class/tag combinations not in
		470	the base set of ASN.1 are decoded into their raw octet strings.
		471
		472	C<Convert::BER::XS> defines two profile variables you can use out of the box:
		473
		474	=over
		475
		476	=item C<$Convert::BER::XS::DEFAULT_PROFILE>
		477
		478	This is the default profile, i.e. the profile that is used when no
		479	profile is specified for de-/encoding.
		480
		481	You can modify it, but remember that this modifies the defaults for all
		482	callers that rely on the default profile.
		483
		484	=item C<$Convert::BER::XS::SNMP_PROFILE>
		485
		486	A profile with mappings for SNMP-specific application tags added. This is
		487	useful when de-/encoding SNMP data.
		488
		489	Example:
		490
		491	$ber = ber_decode $data, $Convert::BER::XS::SNMP_PROFILE;
		492
		493	=back
		494
		495	=head2 The Convert::BER::XS::Profile class
		496
		497	=over
		498
		499	=item $profile = new Convert::BER::XS::Profile
		500
		501	Create a new profile. The profile will be identical to the default
		502	profile.
		503
		504	=item $profile->set ($class, $tag, $type)
		505
		506	Sets the mapping for the given C<$class>/C<$tag> combination to C<$type>,
		507	which must be one of the C<BER_TYPE_*> constants.
		508
		509	Note that currently, the mapping is stored in a flat array, so large
		510	values of C<$tag> will consume large amounts of memory.
		511
		512	Example:
		513
		514	$profile = new Convert::BER::XS::Profile;
		515	$profile->set (ASN_APPLICATION, SNMP_COUNTER32, BER_TYPE_INT);
		516	$ber = ber_decode $data, $profile;
		517
		518	=item $type = $profile->get ($class, $tag)
		519
		520	Returns the BER type mapped to the given C<$class>/C<$tag> combination.
		521
		522	=back
		523
		524	=head2 BER TYPES
		525
		526	This lists the predefined BER types - you can map any C<CLASS>/C<TAG>
		527	combination to any C<BER_TYPE_*>.
		528
		529	=over
		530
		531	=item C<BER_TYPE_BYTES>
		532
		533	The raw octets of the value. This is the default type for unknown tags and
		534	de-/encodes the value as if it were an octet string, i.e. by copying the
		535	raw bytes.
		536
		537	=item C<BER_TYPE_UTF8>
		538
		539	Like C<BER_TYPE_BYTES>, but decodes the value as if it were a UTF-8 string
		540	(without validation!) and encodes a perl unicode string into a UTF-8 BER
		541	string.
		542
		543	=item C<BER_TYPE_UCS2>
		544
		545	Similar to C<BER_TYPE_UTF8>, but treats the BER value as UCS-2 encoded
		546	string.
		547
		548	=item C<BER_TYPE_UCS4>
		549
		550	Similar to C<BER_TYPE_UTF8>, but treats the BER value as UCS-4 encoded
		551	string.
		552
		553	=item C<BER_TYPE_INT>
		554
		555	Encodes and decodes a BER integer value to a perl integer scalar. This
		556	should correctly handle 64 bit signed and unsigned values.
		557
		558	=item C<BER_TYPE_OID>
		559
		560	Encodes and decodes an OBJECT IDENTIFIER into dotted form without leading
		561	dot, e.g. C<1.3.6.1.213>.
		562
		563	=item C<BER_TYPE_RELOID>
		564
		565	Same as C<BER_TYPE_OID> but uses relative object identifier
		566	encoding: ASN.1 has this hack of encoding the first two OID components
		567	into a single integer in a weird attempt to save an insignificant amount
		568	of space in an otherwise wasteful encoding, and relative OIDs are
		569	basically OIDs without this hack. The practical difference is that the
		570	second component of an OID can only have the values 1..40, while relative
		571	OIDs do not have this restriction.
		572
		573	=item C<BER_TYPE_NULL>
		574
		575	Decodes an C<ASN_NULL> value into C<undef>, and always encodes a
		576	C<ASN_NULL> type, regardless of the perl value.
		577
		578	=item C<BER_TYPE_BOOL>
		579
		580	Decodes an C<ASN_BOOLEAN> value into C<0> or C<1>, and encodes a perl
		581	boolean value into an C<ASN_BOOLEAN>.
		582
		583	=item C<BER_TYPE_REAL>
		584
		585	Decodes/encodes a BER real value. NOT IMPLEMENTED.
		586
		587	=item C<BER_TYPE_IPADDRESS>
		588
		589	Decodes/encodes a four byte string into an IPv4 dotted-quad address string
		590	in Perl. Given the obsolete nature of this type, this is a low-effort
		591	implementation that simply uses C<sprintf> and C<sscanf>-style conversion,
		592	so it won't handle all string forms supported by C<inet_aton> for example.
		593
		594	=item C<BER_TYPE_CROAK>
		595
		596	Always croaks when encountered during encoding or decoding - the
		597	default behaviour when encountering an unknown type is to treat it as
		598	C<BER_TYPE_BYTES>. When you don't want that but instead prefer a hard
		599	error for some types, then C<BER_TYPE_CROAK> is for you.
		600
		601	=back
		602
		603	=head2 Example Profile
		604
		605	The following creates a profile suitable for SNMP - it's exactly identical
		606	to the C<$Convert::BER::XS::SNMP_PROFILE> profile.
		607
		608	our $SNMP_PROFILE = new Convert::BER::XS::Profile;
		609
		610	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS);
		611	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT);
		612	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT);
		613	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT);
		614	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_IPADDRESS);
		615	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT);
		616
		617	=cut
		618
		619	our $DEFAULT_PROFILE = new Convert::BER::XS::Profile;
		620
		621	$DEFAULT_PROFILE->_set_default;
		622
		623	# additional SNMP application types
		624	our $SNMP_PROFILE = new Convert::BER::XS::Profile;
		625
		626	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS);
		627	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT);
		628	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT);
		629	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT);
		630	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_IPADDRESS);
		631	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT);
318		632
319	1;	633	1;
320		634
321	=head2 BUGS / SHORTCOMINGs	635	=head2 LIMITATIONS/NOTES
322		636
323	This module does have a number of SNMPisms hardcoded, such as the SNMP	637	This module can only en-/decode 64 bit signed and unsigned integers, and
324	tags for Unsigned32 and so on. More configurability is needed, and, if	638	only when your perl supports those.
325	ever implemented, will come in a form similar to how L<JSON::XS> and	639
326	L<CBOR::XS> respresent things, namely with an object-oriented interface.	640	This module does not generally care about ranges, i.e. it will happily
		641	de-/encode 64 bit integers into an C<ASN_INTEGER> value, or a negative
		642	number into an C<SNMP_COUNTER64>.
		643
		644	OBJECT IDENTIFIEERs cannot have unlimited length, although the limit is
		645	much larger than e.g. the one imposed by SNMP or other protocols,a nd is
		646	about 4kB.
		647
		648	Indefinite length encoding is not supported.
		649
		650	Constructed strings are decoded just fine, but there should be a way to
		651	join them for convenience.
		652
		653	REAL values are not supported and will currently croak.
		654
		655	The encoder and decoder tend to accept more formats than should be
		656	strictly supported.
		657
		658	This module has undergone little to no testing so far.
		659
		660	=head2 ITHREADS SUPPORT
		661
		662	This module is unlikely to work when the (officially discouraged) ithreads
		663	are in use.
327		664
328	=head1 AUTHOR	665	=head1 AUTHOR
329		666
330	Marc Lehmann <schmorp@schmorp.de>	667	Marc Lehmann <schmorp@schmorp.de>
331	http://software.schmorp.de/pkg/Convert-BER-XS	668	http://software.schmorp.de/pkg/Convert-BER-XS

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Comparing Convert-BER-XS/XS.pm (file contents): Revision 1.11 by root, Fri Apr 19 20:44:34 2019 UTC vs. Revision 1.35 by root, Sat Apr 20 21:51:40 2019 UTC

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Comparing Convert-BER-XS/XS.pm (file contents):
Revision 1.11 by root, Fri Apr 19 20:44:34 2019 UTC vs.
Revision 1.35 by root, Sat Apr 20 21:51:40 2019 UTC