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

Comparing Convert-BER-XS/XS.pm (file contents):
Revision 1.9 by root, Fri Apr 19 20:43:12 2019 UTC vs.
Revision 1.29 by root, Sat Apr 20 15:39:13 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_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
		140
		141	=item C<:decode>
		142
		143	C<ber_decode> and the match helper functions:
		144
		145	ber_decode ber_is ber_is_seq ber_is_int ber_is_oid
		146
		147	=item C<:encode>
		148
		149	C<ber_encode> and the construction helper functions:
		150
		151	ber_encode ber_int
		152
		153	=back
78		154
79	=head2 ASN.1/BER/DER/... BASICS	155	=head2 ASN.1/BER/DER/... BASICS
80		156
81	ASN.1 is a strange language that can be sed to describe protocols and	157	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	158	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	159	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.	160	of this module, and is used in SNMP, LDAP or X.509 for example.
85		161
86	While ASN.1 defines a schema that is useful to interpret encoded data,	162	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	163	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,	164	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	165	but you can nevertheless decode the overall structure, even if you end up
90	with just a binary blob for the actual value.	166	with just a binary blob for the actual value.
91		167
92	This works because BER values are tagged with a type and a namespace,	168	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	169	and also have a flag that says whether a value consists of subvalues (is
94	"constructed") or not (is "primitive").	170	"constructed") or not (is "primitive").
95		171
96	Tags are simple integers, and ASN.1 defines a somewhat weird assortment of	172	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	173	of those - for example, you have one integers and 16(!) different
98	string types, but there is no unsigned32 type for example. Different	174	string types, but there is no Unsigned32 type for example. Different
99	applications work around this in different ways, for example, SNMP defines	175	applications work around this in different ways, for example, SNMP defines
100	application-specific Gauge32, Counter32 and Unsigned32, which are mapped	176	application-specific Gauge32, Counter32 and Unsigned32, which are mapped
101	to two different tags: you can distinguish between Counter32 and the	177	to two different tags: you can distinguish between Counter32 and the
102	others, but not between Gause32 and Unsigned32, without the ASN.1 schema.	178	others, but not between Gause32 and Unsigned32, without the ASN.1 schema.
103		179
…		…
106	=head2 DECODED BER REPRESENTATION	182	=head2 DECODED BER REPRESENTATION
107		183
108	This module represents every BER value as a 4-element tuple (actually an	184	This module represents every BER value as a 4-element tuple (actually an
109	array-reference):	185	array-reference):
110		186
111	[CLASS, TAG, CONSTRUCTED, DATA]	187	[CLASS, TAG, FLAGS, DATA]
		188
		189	For example:
		190
		191	[ASN_UNIVERSAL, ASN_INTEGER, 0, 177] # the integer 177
		192	[ASN_UNIVERSAL, ASN_OCTET_STRING, 0, "john"] # the string "john"
		193	[ASN_UNIVERSAL, ASN_OID, 0, "1.3.6.133"] # some OID
		194	[ASN_UNIVERSAL, ASN_SEQUENCE, 1, [ [ASN_UNIVERSAL... # a sequence
112		195
113	To avoid non-descriptive hardcoded array index numbers, this module	196	To avoid non-descriptive hardcoded array index numbers, this module
114	defines symbolic constants to access these members: C<BER_CLASS>,	197	defines symbolic constants to access these members: C<BER_CLASS>,
115	C<BER_TAG>, C<BER_CONSTRUCTED> and C<BER_DATA>.	198	C<BER_TAG>, C<BER_FLAGS> and C<BER_DATA>.
116		199
117	Also, the first three members are integers with a little caveat: for	200	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	201	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	202	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.:	203	I<DATA> member, and you may re-assign the array itself, e.g.:
121		204
122	$ber = ber_decode $binbuf;	205	$ber = ber_decode $binbuf;
123		206
124	# the following is NOT legal:	207	# the following is NOT legal:
125	$ber->[BER_CLASS] = ASN_PRIVATE; # ERROR, class/tag/constructed are readonly(!)	208	$ber->[BER_CLASS] = ASN_PRIVATE; # ERROR, CLASS/TAG/FLAGS are READ ONLY(!)
126		209
127	# but all of the following are fine:	210	# but all of the following are fine:
128	$ber->[BER_DATA] = "string";	211	$ber->[BER_DATA] = "string";
129	$ber->[BER_DATA] = [ASN_UNIVERSAL, ASN_INTEGER32, 0, 123];	212	$ber->[BER_DATA] = [ASN_UNIVERSAL, ASN_INTEGER, 0, 123];
130	@$ber = (ASN_APPLICATION, SNMP_TIMETICKS, 1000);	213	@$ber = (ASN_APPLICATION, SNMP_TIMETICKS, 0, 1000);
131		214
132	I<CLASS> is something like a namespace for I<TAG>s - there is the	215	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	216	C<ASN_UNIVERSAL> namespace which defines tags common to all ASN.1
134	implementations, the C<ASN_APPLICATION> namespace which defines tags for	217	implementations, the C<ASN_APPLICATION> namespace which defines tags for
135	specific applications (for example, the SNMP C<Unsigned32> type is in this	218	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.	219	namespace), a special-purpose context namespace (C<ASN_CONTEXT>, used e.g.
137	for C<CHOICE>) and a private namespace (C<ASN_PRIVATE>).	220	for C<CHOICE>) and a private namespace (C<ASN_PRIVATE>).
138		221
139	The meaning of the I<TAG> depends on the namespace, and defines a	222	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	223	(partial) interpretation of the data value. For example, SNMP defines
141	application namespace knowledge ix hardcoded into this module, so it	224	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	225	of these, you need to tell this module how to handle those via profiles.
143	integers.
144		226
145	The most common tags in the C<ASN_UNIVERSAL> namespace are	227	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>,	228	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	229	C<ASN_OBJECT_IDENTIFIER>, C<ASN_SEQUENCE>, C<ASN_SET> and
148	C<ASN_IA5_STRING>.	230	C<ASN_IA5_STRING>.
149		231
150	The most common tags in SNMP's C<ASN_APPLICATION> namespace	232	The most common tags in SNMP's C<ASN_APPLICATION> namespace are
151	are C<SNMP_IPADDRESS>, C<SNMP_COUNTER32>, C<SNMP_UNSIGNED32>,	233	C<SNMP_COUNTER32>, C<SNMP_UNSIGNED32>, C<SNMP_TIMETICKS> and
152	C<SNMP_TIMETICKS>, C<SNMP_OPAQUE> and C<SNMP_COUNTER64>.	234	C<SNMP_COUNTER64>.
153		235
154	The I<CONSTRUCTED> flag is really just a boolean - if it is false, the	236	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	237	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"	238	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	239	then the value is "constructed" which just means it contains a list of
158	en-/decode as BER tuples themselves.	240	subvalues which this module will en-/decode as BER tuples themselves.
159		241
160	The I<DATA> value is either a reference to an array of further tuples (if	242	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,	243	(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)	244	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	245	a binary string with the raw octets if this module doesn't know how to
164	interpret the namespace/tag.	246	interpret the namespace/tag.
165		247
166	Thus, you can always decode a BER data structure and at worst you get a	248	Thus, you can always decode a BER data structure and at worst you get a
167	string in place of some nice decoded value.	249	string in place of some nice decoded value.
168		250
…		…
170		252
171	=head2 DECODING AND ENCODING	253	=head2 DECODING AND ENCODING
172		254
173	=over	255	=over
174		256
175	=item $tuple = ber_decoded $bindata	257	=item $tuple = ber_decoded $bindata[, $profile]
176		258
177	Decodes binary BER data in C<$bindata> and returns the resulting BER	259	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	260	tuple. Croaks on any decoding error, so the returned C<$tuple> is always
179	valid.	261	valid.
180		262
		263	How tags are interpreted is defined by the second argument, which must
		264	be a C<Convert::BER::XS::Profile> object. If it is missing, the default
		265	profile will be used (C<$Convert::BER::XS::DEFAULT_PROFILE>).
		266
		267	In addition to rolling your own, this module provides a
		268	C<$Convert::BER::XS::SNMP_PROFILE> that knows about the additional SNMP
		269	types.
		270
		271	Example: decode a BER blob using the default profile - SNMP values will be
		272	decided as raw strings.
		273
		274	$tuple = ber_decode $data;
		275
		276	Example: as above, but use the provided SNMP profile.
		277
		278	$tuple = ber_encode $data, $Convert::BER::XS::SNMP_PROFILE;
		279
181	=item $bindata = ber_encode $tuple	280	=item $bindata = ber_encode $tuple[, $profile]
182		281
183	Encodes the BER tuple into a BER/DER data structure.	282	Encodes the BER tuple into a BER/DER data structure. AS with
		283	Cyber_decode>, an optional profile can be given.
		284
		285	The encoded data should be both BER and DER ("shortest form") compliant
		286	unless the input says otherwise (e.g. it uses constructed strings).
184		287
185	=back	288	=back
186		289
187	=head2 HELPER FUNCTIONS	290	=head2 HELPER FUNCTIONS
188		291
189	Working with a 4-tuple for every value can be annoying. Or, rather, I<is>	292	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	293	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:	294	functions, both to match BER tuples and to construct BER tuples:
192		295
193	=head3 MATCH HELPERS	296	=head3 MATCH HELPERS
194		297
195	Thse functions accept a BER tuple as first argument and either paertially	298	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	299	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.	300	a value, and one which only matches the type and returns the value.
198		301
199	They do check whether valid tuples are passed in and croak otherwise. As	302	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	303	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.	304	tuple reference, in which case they silently fail to match.
202		305
203	=over	306	=over
204		307
205	=item $bool = ber_is $tuple, $class, $tag, $constructed, $data	308	=item $bool = ber_is $tuple, $class, $tag, $flags, $data
206		309
207	This takes a BER C<$tuple> and matches its elements agains the privded	310	This takes a BER C<$tuple> and matches its elements against the provided
208	values, all of which are optional - values that are either missing or	311	values, all of which are optional - values that are either missing or
209	C<undef> will be ignored, the others will be matched exactly (e.g. as if	312	C<undef> will be ignored, the others will be matched exactly (e.g. as if
210	you used C<==> or C<eq> (for C<$data>)).	313	you used C<==> or C<eq> (for C<$data>)).
211		314
212	Some examples:	315	Some examples:
…		…
215	orf die "tuple is not an ASN SEQUENCE";	318	orf die "tuple is not an ASN SEQUENCE";
216		319
217	ber_is $tuple, ASN_UNIVERSAL, ASN_NULL	320	ber_is $tuple, ASN_UNIVERSAL, ASN_NULL
218	or die "tuple is not an ASN NULL value";	321	or die "tuple is not an ASN NULL value";
219		322
220	ber_is $tuple, ASN_UNIVERSAL, ASN_INTEGER32, 0, 50	323	ber_is $tuple, ASN_UNIVERSAL, ASN_INTEGER, 0, 50
221	or die "BER integer must be 50";	324	or die "BER integer must be 50";
222		325
223	=item $seq = ber_is_seq $tuple	326	=item $seq = ber_is_seq $tuple
224		327
225	Returns the sequence members (the array of subvalues) if the C<$tuple> is	328	Returns the sequence members (the array of subvalues) if the C<$tuple> is
…		…
232	my $snmp = ber_is_seq $ber	335	my $snmp = ber_is_seq $ber
233	or die "SNMP packet invalid: does not start with SEQUENCE";	336	or die "SNMP packet invalid: does not start with SEQUENCE";
234		337
235	# now we know $snmp is a sequence, so decode the SNMP version	338	# now we know $snmp is a sequence, so decode the SNMP version
236		339
237	my $version = ber_is_i32 $snmp->[0]	340	my $version = ber_is_int $snmp->[0]
238	or die "SNMP packet invalid: does not start with version number";	341	or die "SNMP packet invalid: does not start with version number";
239		342
240	=item $bool = ber_is_i32 $tuple, $i32	343	=item $bool = ber_is_int $tuple, $int
241		344
242	Returns a true value if the C<$tuple> represents an ASN INTEGER32 with	345	Returns a true value if the C<$tuple> represents an ASN INTEGER with
243	the value C<$i32>.	346	the value C<$int>.
244		347
245	=item $i32 = ber_is_i32 $tuple	348	=item $int = ber_is_int $tuple
246		349
247	Returns true (and extracts the integer value) if the C<$tuple> is an ASN	350	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	351	C<ASN_INTEGER>. For C<0>, this function returns a special value that is 0
249	true.	352	but true.
250		353
251	=item $bool = ber_is_oid $tuple, $oid_string	354	=item $bool = ber_is_oid $tuple, $oid_string
252		355
253	Returns true if the C<$tuple> represents an ASN_OBJECT_IDENTIFIER	356	Returns true if the C<$tuple> represents an ASN_OBJECT_IDENTIFIER
254	that exactly matches C$oid_string>. Exmaple:	357	that exactly matches C<$oid_string>. Example:
255		358
256	ber_is_oid $tuple, "1.3.6.1.4"	359	ber_is_oid $tuple, "1.3.6.1.4"
257	or die "oid must be 1.3.6.1.4";	360	or die "oid must be 1.3.6.1.4";
258		361
259	=item $oid = ber_is_oid $tuple	362	=item $oid = ber_is_oid $tuple
…		…
265		368
266	=head3 CONSTRUCTION HELPERS	369	=head3 CONSTRUCTION HELPERS
267		370
268	=over	371	=over
269		372
270	=item $tuple = ber_i32 $value	373	=item $tuple = ber_int $value
271		374
272	Constructs a new C<ASN_INTEGER32> tuple.	375	Constructs a new C<ASN_INTEGER> tuple.
273		376
274	=back	377	=back
275		378
276	=head2 RELATIONSHIP TO L<Convert::BER> and L<Convert::ASN1>	379	=head2 RELATIONSHIP TO L<Convert::BER> and L<Convert::ASN1>
277		380
…		…
287	use common::sense;	390	use common::sense;
288		391
289	use XSLoader ();	392	use XSLoader ();
290	use Exporter qw(import);	393	use Exporter qw(import);
291		394
292	our $VERSION = 0.2;	395	our $VERSION;
293		396
		397	BEGIN {
		398	$VERSION = 0.8;
294	XSLoader::load __PACKAGE__, $VERSION;	399	XSLoader::load __PACKAGE__, $VERSION;
		400	}
295		401
296	our %EXPORT_TAGS = (	402	our %EXPORT_TAGS = (
		403	const_index => [qw(
		404	BER_CLASS BER_TAG BER_FLAGS BER_DATA
		405	)],
297	const => [qw(	406	const_asn => [qw(
298	BER_CLASS BER_TAG BER_CONSTRUCTED BER_DATA
299
300	ASN_BOOLEAN ASN_INTEGER32 ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER ASN_TAG_BER ASN_TAG_MASK	407	ASN_BOOLEAN ASN_INTEGER ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER
301	ASN_CONSTRUCTED ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE ASN_CLASS_MASK ASN_CLASS_SHIFT	408	ASN_OBJECT_DESCRIPTOR ASN_OID ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED
302	ASN_SEQUENCE	409	ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING
303		410	ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING
		411	ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING
		412	ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING
		413
		414	ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE
		415	)],
		416	const_ber_type => [qw(
		417	BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT
		418	BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL
		419	BER_TYPE_IPADDRESS BER_TYPE_CROAK
		420	)],
		421	const_snmp => [qw(
304	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64	422	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
305	)],	423	)],
		424	decode => [qw(
		425	ber_decode
		426	ber_is ber_is_seq ber_is_int ber_is_oid
		427	)],
306	encode => [qw(	428	encode => [qw(
307	ber_decode
308	ber_is ber_is_seq ber_is_i32 ber_is_oid
309	)],
310	decode => [qw(
311	ber_encode	429	ber_encode
		430	ber_int
312	)],	431	)],
313	);	432	);
314		433
315	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;	434	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;
316		435
317	$EXPORT_TAGS{all} = \@EXPORT_OK;	436	$EXPORT_TAGS{all} = \@EXPORT_OK;
		437	$EXPORT_TAGS{const} = [map @{ $EXPORT_TAGS{$_} }, qw(const_index const_asn)];
		438
		439	=head1 PROFILES
		440
		441	While any BER data can be correctly encoded and decoded out of the box, it
		442	can be inconvenient to have to manually decode some values into a "better"
		443	format: for instance, SNMP TimeTicks values are decoded into the raw octet
		444	strings of their BER representation, which is quite hard to decode. With
		445	profiles, you can change which class/tag combinations map to which decoder
		446	function inside C<ber_decode> (and of course also which encoder functions
		447	are used in C<ber_encode>).
		448
		449	This works by mapping specific class/tag combinations to an internal "ber
		450	type".
		451
		452	The default profile supports the standard ASN.1 types, but no
		453	application-specific ones. This means that class/tag combinations not in
		454	the base set of ASN.1 are decoded into their raw octet strings.
		455
		456	C<Convert::BER::XS> defines two profile variables you can use out of the box:
		457
		458	=over
		459
		460	=item C<$Convert::BER::XS::DEFAULT_PROFILE>
		461
		462	This is the default profile, i.e. the profile that is used when no
		463	profile is specified for de-/encoding.
		464
		465	You can modify it, but remember that this modifies the defaults for all
		466	callers that rely on the default profile.
		467
		468	=item C<$Convert::BER::XS::SNMP_PROFILE>
		469
		470	A profile with mappings for SNMP-specific application tags added. This is
		471	useful when de-/encoding SNMP data.
		472
		473	Example:
		474
		475	$ber = ber_decode $data, $Convert::BER::XS::SNMP_PROFILE;
		476
		477	=back
		478
		479	=head2 The Convert::BER::XS::Profile class
		480
		481	=over
		482
		483	=item $profile = new Convert::BER::XS::Profile
		484
		485	Create a new profile. The profile will be identical to the default
		486	profile.
		487
		488	=item $profile->set ($class, $tag, $type)
		489
		490	Sets the mapping for the given C<$class>/C<$tag> combination to C<$type>,
		491	which must be one of the C<BER_TYPE_*> constants.
		492
		493	Note that currently, the mapping is stored in a flat array, so large
		494	values of C<$tag> will consume large amounts of memory.
		495
		496	Example:
		497
		498	$profile = new Convert::BER::XS::Profile;
		499	$profile->set (ASN_APPLICATION, SNMP_COUNTER32, BER_TYPE_INT);
		500	$ber = ber_decode $data, $profile;
		501
		502	=item $type = $profile->get ($class, $tag)
		503
		504	Returns the BER type mapped to the given C<$class>/C<$tag> combination.
		505
		506	=back
		507
		508	=head2 BER TYPES
		509
		510	This lists the predefined BER types - you can map any C<CLASS>/C<TAG>
		511	combination to any C<BER_TYPE_*>.
		512
		513	=over
		514
		515	=item C<BER_TYPE_BYTES>
		516
		517	The raw octets of the value. This is the default type for unknown tags and
		518	de-/encodes the value as if it were an octet string, i.e. by copying the
		519	raw bytes.
		520
		521	=item C<BER_TYPE_UTF8>
		522
		523	Like C<BER_TYPE_BYTES>, but decodes the value as if it were a UTF-8 string
		524	(without validation!) and encodes a perl unicode string into a UTF-8 BER
		525	string.
		526
		527	=item C<BER_TYPE_UCS2>
		528
		529	Similar to C<BER_TYPE_UTF8>, but treats the BER value as UCS-2 encoded
		530	string.
		531
		532	=item C<BER_TYPE_UCS4>
		533
		534	Similar to C<BER_TYPE_UTF8>, but treats the BER value as UCS-4 encoded
		535	string.
		536
		537	=item C<BER_TYPE_INT>
		538
		539	Encodes and decodes a BER integer value to a perl integer scalar. This
		540	should correctly handle 64 bit signed and unsigned values.
		541
		542	=item C<BER_TYPE_OID>
		543
		544	Encodes and decodes an OBJECT IDENTIFIER into dotted form without leading
		545	dot, e.g. C<1.3.6.1.213>.
		546
		547	=item C<BER_TYPE_RELOID>
		548
		549	Same as C<BER_TYPE_OID> but uses relative object identifier
		550	encoding: ASN.1 has this hack of encoding the first two OID components
		551	into a single integer in a weird attempt to save an insignificant amount
		552	of space in an otherwise wasteful encoding, and relative OIDs are
		553	basically OIDs without this hack. The practical difference is that the
		554	second component of an OID can only have the values 1..40, while relative
		555	OIDs do not have this restriction.
		556
		557	=item C<BER_TYPE_NULL>
		558
		559	Decodes an C<ASN_NULL> value into C<undef>, and always encodes a
		560	C<ASN_NULL> type, regardless of the perl value.
		561
		562	=item C<BER_TYPE_BOOL>
		563
		564	Decodes an C<ASN_BOOLEAN> value into C<0> or C<1>, and encodes a perl
		565	boolean value into an C<ASN_BOOLEAN>.
		566
		567	=item C<BER_TYPE_REAL>
		568
		569	Decodes/encodes a BER real value. NOT IMPLEMENTED.
		570
		571	=item C<BER_TYPE_IPADDRESS>
		572
		573	Decodes/encodes a four byte string into an IPv4 dotted-quad address string
		574	in Perl. Given the obsolete nature of this type, this is a low-effort
		575	implementation that simply uses C<sprintf> and C<sscanf>-style conversion,
		576	so it won't handle all string forms supported by C<inet_aton> for example.
		577
		578	=item C<BER_TYPE_CROAK>
		579
		580	Always croaks when encountered during encoding or decoding - the
		581	default behaviour when encountering an unknown type is to treat it as
		582	C<BER_TYPE_BYTES>. When you don't want that but instead prefer a hard
		583	error for some types, then C<BER_TYPE_CROAK> is for you.
		584
		585	=back
		586
		587	=cut
		588
		589	our $DEFAULT_PROFILE = new Convert::BER::XS::Profile;
		590	our $SNMP_PROFILE = new Convert::BER::XS::Profile;
		591
		592	# additional SNMP application types
		593	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS);
		594	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT);
		595	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT);
		596	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT);
		597	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_IPADDRESS);
		598	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT);
		599
		600	$DEFAULT_PROFILE->_set_default;
318		601
319	1;	602	1;
320		603
321	=head2 BUGS / SHORTCOMINGs	604	=head2 LIMITATIONS/NOTES
322		605
323	This module does have a number of SNMPisms hardcoded, such as the SNMP	606	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	607	only when your perl supports those.
325	ever implemented, will come in a form similar to how L<JSON::XS> and	608
326	L<CBOR::XS> respresent things, namely with an object-oriented interface.	609	This module does not generally care about ranges, i.e. it will happily
		610	de-/encode 64 bit integers into an C<ASN_INTEGER> value, or a negative
		611	number into an C<SNMP_COUNTER64>.
		612
		613	OBJECT IDENTIFIEERs cannot have unlimited length, although the limit is
		614	much larger than e.g. the one imposed by SNMP or other protocols,a nd is
		615	about 4kB.
		616
		617	Indefinite length encoding is not supported.
		618
		619	Constructed strings are decoded just fine, but there should be a way to
		620	join them for convenience.
		621
		622	REAL values are not supported and will currently croak.
		623
		624	This module has undergone little to no testing so far.
		625
		626	=head2 ITHREADS SUPPORT
		627
		628	This module is unlikely to work when the (officially discouraged) ithreads
		629	are in use.
327		630
328	=head1 AUTHOR	631	=head1 AUTHOR
329		632
330	Marc Lehmann <schmorp@schmorp.de>	633	Marc Lehmann <schmorp@schmorp.de>
331	http://software.schmorp.de/pkg/Convert-BER-XS	634	http://software.schmorp.de/pkg/Convert-BER-XS

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Comparing Convert-BER-XS/XS.pm (file contents): Revision 1.9 by root, Fri Apr 19 20:43:12 2019 UTC vs. Revision 1.29 by root, Sat Apr 20 15:39:13 2019 UTC

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Comparing Convert-BER-XS/XS.pm (file contents):
Revision 1.9 by root, Fri Apr 19 20:43:12 2019 UTC vs.
Revision 1.29 by root, Sat Apr 20 15:39:13 2019 UTC