[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 1.33 by root, Sat Apr 20 17:23:21 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_is ber_is_seq ber_is_int ber_is_oid
		147
		148	=item C<:encode>
		149
		150	C<ber_encode> and the construction helper functions:
		151
		152	ber_encode ber_int
		153
		154	=back
78		155
79	=head2 ASN.1/BER/DER/... BASICS	156	=head2 ASN.1/BER/DER/... BASICS
80		157
81	ASN.1 is a strange language that can be sed to describe protocols and	158	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	159	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	160	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.	161	of this module, and is used in SNMP, LDAP or X.509 for example.
85		162
86	While ASN.1 defines a schema that is useful to interpret encoded data,	163	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	164	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,	165	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	166	but you can nevertheless decode the overall structure, even if you end up
90	with just a binary blob for the actual value.	167	with just a binary blob for the actual value.
91		168
92	This works because BER values are tagged with a type and a namespace,	169	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	170	and also have a flag that says whether a value consists of subvalues (is
94	"constructed") or not (is "primitive").	171	"constructed") or not (is "primitive").
95		172
96	Tags are simple integers, and ASN.1 defines a somewhat weird assortment of	173	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	174	of those - for example, you have one integers and 16(!) different
98	string types, but there is no unsigned32 type for example. Different	175	string types, but there is no Unsigned32 type for example. Different
99	applications work around this in different ways, for example, SNMP defines	176	applications work around this in different ways, for example, SNMP defines
100	application-specific Gauge32, Counter32 and Unsigned32, which are mapped	177	application-specific Gauge32, Counter32 and Unsigned32, which are mapped
101	to two different tags: you can distinguish between Counter32 and the	178	to two different tags: you can distinguish between Counter32 and the
102	others, but not between Gause32 and Unsigned32, without the ASN.1 schema.	179	others, but not between Gause32 and Unsigned32, without the ASN.1 schema.
103		180
…		…
106	=head2 DECODED BER REPRESENTATION	183	=head2 DECODED BER REPRESENTATION
107		184
108	This module represents every BER value as a 4-element tuple (actually an	185	This module represents every BER value as a 4-element tuple (actually an
109	array-reference):	186	array-reference):
110		187
111	[CLASS, TAG, CONSTRUCTED, DATA]	188	[CLASS, TAG, FLAGS, DATA]
		189
		190	For example:
		191
		192	[ASN_UNIVERSAL, ASN_INTEGER, 0, 177] # the integer 177
		193	[ASN_UNIVERSAL, ASN_OCTET_STRING, 0, "john"] # the string "john"
		194	[ASN_UNIVERSAL, ASN_OID, 0, "1.3.6.133"] # some OID
		195	[ASN_UNIVERSAL, ASN_SEQUENCE, 1, [ [ASN_UNIVERSAL... # a sequence
112		196
113	To avoid non-descriptive hardcoded array index numbers, this module	197	To avoid non-descriptive hardcoded array index numbers, this module
114	defines symbolic constants to access these members: C<BER_CLASS>,	198	defines symbolic constants to access these members: C<BER_CLASS>,
115	C<BER_TAG>, C<BER_CONSTRUCTED> and C<BER_DATA>.	199	C<BER_TAG>, C<BER_FLAGS> and C<BER_DATA>.
116		200
117	Also, the first three members are integers with a little caveat: for	201	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	202	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	203	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.:	204	I<DATA> member, and you may re-assign the array itself, e.g.:
121		205
122	$ber = ber_decode $binbuf;	206	$ber = ber_decode $binbuf;
123		207
124	# the following is NOT legal:	208	# the following is NOT legal:
125	$ber->[BER_CLASS] = ASN_PRIVATE; # ERROR, class/tag/constructed are readonly(!)	209	$ber->[BER_CLASS] = ASN_PRIVATE; # ERROR, CLASS/TAG/FLAGS are READ ONLY(!)
126		210
127	# but all of the following are fine:	211	# but all of the following are fine:
128	$ber->[BER_DATA] = "string";	212	$ber->[BER_DATA] = "string";
129	$ber->[BER_DATA] = [ASN_UNIVERSAL, ASN_INTEGER32, 0, 123];	213	$ber->[BER_DATA] = [ASN_UNIVERSAL, ASN_INTEGER, 0, 123];
130	@$ber = (ASN_APPLICATION, SNMP_TIMETICKS, 1000);	214	@$ber = (ASN_APPLICATION, SNMP_TIMETICKS, 0, 1000);
131		215
132	I<CLASS> is something like a namespace for I<TAG>s - there is the	216	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	217	C<ASN_UNIVERSAL> namespace which defines tags common to all ASN.1
134	implementations, the C<ASN_APPLICATION> namespace which defines tags for	218	implementations, the C<ASN_APPLICATION> namespace which defines tags for
135	specific applications (for example, the SNMP C<Unsigned32> type is in this	219	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.	220	namespace), a special-purpose context namespace (C<ASN_CONTEXT>, used e.g.
137	for C<CHOICE>) and a private namespace (C<ASN_PRIVATE>).	221	for C<CHOICE>) and a private namespace (C<ASN_PRIVATE>).
138		222
139	The meaning of the I<TAG> depends on the namespace, and defines a	223	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	224	(partial) interpretation of the data value. For example, SNMP defines
141	application namespace knowledge ix hardcoded into this module, so it	225	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	226	of these, you need to tell this module how to handle those via profiles.
143	integers.
144		227
145	The most common tags in the C<ASN_UNIVERSAL> namespace are	228	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>,	229	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	230	C<ASN_OBJECT_IDENTIFIER>, C<ASN_SEQUENCE>, C<ASN_SET> and
148	C<ASN_IA5_STRING>.	231	C<ASN_IA5_STRING>.
149		232
150	The most common tags in SNMP's C<ASN_APPLICATION> namespace	233	The most common tags in SNMP's C<ASN_APPLICATION> namespace are
151	are C<SNMP_IPADDRESS>, C<SNMP_COUNTER32>, C<SNMP_UNSIGNED32>,	234	C<SNMP_COUNTER32>, C<SNMP_UNSIGNED32>, C<SNMP_TIMETICKS> and
152	C<SNMP_TIMETICKS>, C<SNMP_OPAQUE> and C<SNMP_COUNTER64>.	235	C<SNMP_COUNTER64>.
153		236
154	The I<CONSTRUCTED> flag is really just a boolean - if it is false, the	237	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	238	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"	239	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	240	then the value is "constructed" which just means it contains a list of
158	en-/decode as BER tuples themselves.	241	subvalues which this module will en-/decode as BER tuples themselves.
159		242
160	The I<DATA> value is either a reference to an array of further tuples (if	243	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,	244	(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)	245	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	246	a binary string with the raw octets if this module doesn't know how to
164	interpret the namespace/tag.	247	interpret the namespace/tag.
165		248
166	Thus, you can always decode a BER data structure and at worst you get a	249	Thus, you can always decode a BER data structure and at worst you get a
167	string in place of some nice decoded value.	250	string in place of some nice decoded value.
168		251
…		…
170		253
171	=head2 DECODING AND ENCODING	254	=head2 DECODING AND ENCODING
172		255
173	=over	256	=over
174		257
175	=item $tuple = ber_decoded $bindata	258	=item $tuple = ber_decoded $bindata[, $profile]
176		259
177	Decodes binary BER data in C<$bindata> and returns the resulting BER	260	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	261	tuple. Croaks on any decoding error, so the returned C<$tuple> is always
179	valid.	262	valid.
180		263
		264	How tags are interpreted is defined by the second argument, which must
		265	be a C<Convert::BER::XS::Profile> object. If it is missing, the default
		266	profile will be used (C<$Convert::BER::XS::DEFAULT_PROFILE>).
		267
		268	In addition to rolling your own, this module provides a
		269	C<$Convert::BER::XS::SNMP_PROFILE> that knows about the additional SNMP
		270	types.
		271
		272	Example: decode a BER blob using the default profile - SNMP values will be
		273	decided as raw strings.
		274
		275	$tuple = ber_decode $data;
		276
		277	Example: as above, but use the provided SNMP profile.
		278
		279	$tuple = ber_encode $data, $Convert::BER::XS::SNMP_PROFILE;
		280
181	=item $bindata = ber_encode $tuple	281	=item $bindata = ber_encode $tuple[, $profile]
182		282
183	Encodes the BER tuple into a BER/DER data structure.	283	Encodes the BER tuple into a BER/DER data structure. AS with
		284	Cyber_decode>, an optional profile can be given.
		285
		286	The encoded data should be both BER and DER ("shortest form") compliant
		287	unless the input says otherwise (e.g. it uses constructed strings).
184		288
185	=back	289	=back
186		290
187	=head2 HELPER FUNCTIONS	291	=head2 HELPER FUNCTIONS
188		292
189	Working with a 4-tuple for every value can be annoying. Or, rather, I<is>	293	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	294	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:	295	functions, both to match BER tuples and to construct BER tuples:
192		296
193	=head3 MATCH HELPERS	297	=head3 MATCH HELPERS
194		298
195	Thse functions accept a BER tuple as first argument and either paertially	299	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	300	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.	301	a value, and one which only matches the type and returns the value.
198		302
199	They do check whether valid tuples are passed in and croak otherwise. As	303	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	304	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.	305	tuple reference, in which case they silently fail to match.
202		306
203	=over	307	=over
204		308
205	=item $bool = ber_is $tuple, $class, $tag, $constructed, $data	309	=item $bool = ber_is $tuple, $class, $tag, $flags, $data
206		310
207	This takes a BER C<$tuple> and matches its elements agains the privded	311	This takes a BER C<$tuple> and matches its elements against the provided
208	values, all of which are optional - values that are either missing or	312	values, all of which are optional - values that are either missing or
209	C<undef> will be ignored, the others will be matched exactly (e.g. as if	313	C<undef> will be ignored, the others will be matched exactly (e.g. as if
210	you used C<==> or C<eq> (for C<$data>)).	314	you used C<==> or C<eq> (for C<$data>)).
211		315
212	Some examples:	316	Some examples:
…		…
215	orf die "tuple is not an ASN SEQUENCE";	319	orf die "tuple is not an ASN SEQUENCE";
216		320
217	ber_is $tuple, ASN_UNIVERSAL, ASN_NULL	321	ber_is $tuple, ASN_UNIVERSAL, ASN_NULL
218	or die "tuple is not an ASN NULL value";	322	or die "tuple is not an ASN NULL value";
219		323
220	ber_is $tuple, ASN_UNIVERSAL, ASN_INTEGER32, 0, 50	324	ber_is $tuple, ASN_UNIVERSAL, ASN_INTEGER, 0, 50
221	or die "BER integer must be 50";	325	or die "BER integer must be 50";
222		326
223	=item $seq = ber_is_seq $tuple	327	=item $seq = ber_is_seq $tuple
224		328
225	Returns the sequence members (the array of subvalues) if the C<$tuple> is	329	Returns the sequence members (the array of subvalues) if the C<$tuple> is
…		…
232	my $snmp = ber_is_seq $ber	336	my $snmp = ber_is_seq $ber
233	or die "SNMP packet invalid: does not start with SEQUENCE";	337	or die "SNMP packet invalid: does not start with SEQUENCE";
234		338
235	# now we know $snmp is a sequence, so decode the SNMP version	339	# now we know $snmp is a sequence, so decode the SNMP version
236		340
237	my $version = ber_is_i32 $snmp->[0]	341	my $version = ber_is_int $snmp->[0]
238	or die "SNMP packet invalid: does not start with version number";	342	or die "SNMP packet invalid: does not start with version number";
239		343
240	=item $bool = ber_is_i32 $tuple, $i32	344	=item $bool = ber_is_int $tuple, $int
241		345
242	Returns a true value if the C<$tuple> represents an ASN INTEGER32 with	346	Returns a true value if the C<$tuple> represents an ASN INTEGER with
243	the value C<$i32>.	347	the value C<$int>.
244		348
245	=item $i32 = ber_is_i32 $tuple	349	=item $int = ber_is_int $tuple
246		350
247	Returns true (and extracts the integer value) if the C<$tuple> is an ASN	351	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	352	C<ASN_INTEGER>. For C<0>, this function returns a special value that is 0
249	true.	353	but true.
250		354
251	=item $bool = ber_is_oid $tuple, $oid_string	355	=item $bool = ber_is_oid $tuple, $oid_string
252		356
253	Returns true if the C<$tuple> represents an ASN_OBJECT_IDENTIFIER	357	Returns true if the C<$tuple> represents an ASN_OBJECT_IDENTIFIER
254	that exactly matches C$oid_string>. Exmaple:	358	that exactly matches C<$oid_string>. Example:
255		359
256	ber_is_oid $tuple, "1.3.6.1.4"	360	ber_is_oid $tuple, "1.3.6.1.4"
257	or die "oid must be 1.3.6.1.4";	361	or die "oid must be 1.3.6.1.4";
258		362
259	=item $oid = ber_is_oid $tuple	363	=item $oid = ber_is_oid $tuple
…		…
265		369
266	=head3 CONSTRUCTION HELPERS	370	=head3 CONSTRUCTION HELPERS
267		371
268	=over	372	=over
269		373
270	=item $tuple = ber_i32 $value	374	=item $tuple = ber_int $value
271		375
272	Constructs a new C<ASN_INTEGER32> tuple.	376	Constructs a new C<ASN_INTEGER> tuple.
273		377
274	=back	378	=back
275		379
276	=head2 RELATIONSHIP TO L<Convert::BER> and L<Convert::ASN1>	380	=head2 RELATIONSHIP TO L<Convert::BER> and L<Convert::ASN1>
277		381
…		…
287	use common::sense;	391	use common::sense;
288		392
289	use XSLoader ();	393	use XSLoader ();
290	use Exporter qw(import);	394	use Exporter qw(import);
291		395
292	our $VERSION = 0.2;	396	our $VERSION;
293		397
		398	BEGIN {
		399	$VERSION = 0.9;
294	XSLoader::load __PACKAGE__, $VERSION;	400	XSLoader::load __PACKAGE__, $VERSION;
		401	}
295		402
296	our %EXPORT_TAGS = (	403	our %EXPORT_TAGS = (
		404	const_index => [qw(
		405	BER_CLASS BER_TAG BER_FLAGS BER_DATA
		406	)],
297	const => [qw(	407	const_asn => [qw(
298	BER_CLASS BER_TAG BER_CONSTRUCTED BER_DATA
299
300	ASN_BOOLEAN ASN_INTEGER32 ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER ASN_TAG_BER ASN_TAG_MASK	408	ASN_BOOLEAN ASN_INTEGER ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER
301	ASN_CONSTRUCTED ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE ASN_CLASS_MASK ASN_CLASS_SHIFT	409	ASN_OBJECT_DESCRIPTOR ASN_OID ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED
302	ASN_SEQUENCE	410	ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING
303		411	ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING
304	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64	412	ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING
		413	ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING
		414
		415	ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE
		416	)],
		417	const_ber_type => [qw(
		418	BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT
		419	BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL
		420	BER_TYPE_IPADDRESS BER_TYPE_CROAK
		421	)],
		422	const_snmp => [qw(
		423	SNMP_IPADDRESS SNMP_COUNTER32 SNMP_GAUGE32 SNMP_UNSIGNED32
		424	SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
		425	)],
		426	decode => [qw(
		427	ber_decode
		428	ber_is ber_is_seq ber_is_int ber_is_oid
305	)],	429	)],
306	encode => [qw(	430	encode => [qw(
307	ber_decode
308	ber_is ber_is_seq ber_is_i32 ber_is_oid
309	)],
310	decode => [qw(
311	ber_encode	431	ber_encode
		432	ber_int
312	)],	433	)],
313	);	434	);
314		435
315	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;	436	our @EXPORT_OK = map @$_, values %EXPORT_TAGS;
316		437
317	$EXPORT_TAGS{all} = \@EXPORT_OK;	438	$EXPORT_TAGS{all} = \@EXPORT_OK;
		439	$EXPORT_TAGS{const} = [map @{ $EXPORT_TAGS{$_} }, qw(const_index const_asn)];
		440
		441	=head1 PROFILES
		442
		443	While any BER data can be correctly encoded and decoded out of the box, it
		444	can be inconvenient to have to manually decode some values into a "better"
		445	format: for instance, SNMP TimeTicks values are decoded into the raw octet
		446	strings of their BER representation, which is quite hard to decode. With
		447	profiles, you can change which class/tag combinations map to which decoder
		448	function inside C<ber_decode> (and of course also which encoder functions
		449	are used in C<ber_encode>).
		450
		451	This works by mapping specific class/tag combinations to an internal "ber
		452	type".
		453
		454	The default profile supports the standard ASN.1 types, but no
		455	application-specific ones. This means that class/tag combinations not in
		456	the base set of ASN.1 are decoded into their raw octet strings.
		457
		458	C<Convert::BER::XS> defines two profile variables you can use out of the box:
		459
		460	=over
		461
		462	=item C<$Convert::BER::XS::DEFAULT_PROFILE>
		463
		464	This is the default profile, i.e. the profile that is used when no
		465	profile is specified for de-/encoding.
		466
		467	You can modify it, but remember that this modifies the defaults for all
		468	callers that rely on the default profile.
		469
		470	=item C<$Convert::BER::XS::SNMP_PROFILE>
		471
		472	A profile with mappings for SNMP-specific application tags added. This is
		473	useful when de-/encoding SNMP data.
		474
		475	Example:
		476
		477	$ber = ber_decode $data, $Convert::BER::XS::SNMP_PROFILE;
		478
		479	=back
		480
		481	=head2 The Convert::BER::XS::Profile class
		482
		483	=over
		484
		485	=item $profile = new Convert::BER::XS::Profile
		486
		487	Create a new profile. The profile will be identical to the default
		488	profile.
		489
		490	=item $profile->set ($class, $tag, $type)
		491
		492	Sets the mapping for the given C<$class>/C<$tag> combination to C<$type>,
		493	which must be one of the C<BER_TYPE_*> constants.
		494
		495	Note that currently, the mapping is stored in a flat array, so large
		496	values of C<$tag> will consume large amounts of memory.
		497
		498	Example:
		499
		500	$profile = new Convert::BER::XS::Profile;
		501	$profile->set (ASN_APPLICATION, SNMP_COUNTER32, BER_TYPE_INT);
		502	$ber = ber_decode $data, $profile;
		503
		504	=item $type = $profile->get ($class, $tag)
		505
		506	Returns the BER type mapped to the given C<$class>/C<$tag> combination.
		507
		508	=back
		509
		510	=head2 BER TYPES
		511
		512	This lists the predefined BER types - you can map any C<CLASS>/C<TAG>
		513	combination to any C<BER_TYPE_*>.
		514
		515	=over
		516
		517	=item C<BER_TYPE_BYTES>
		518
		519	The raw octets of the value. This is the default type for unknown tags and
		520	de-/encodes the value as if it were an octet string, i.e. by copying the
		521	raw bytes.
		522
		523	=item C<BER_TYPE_UTF8>
		524
		525	Like C<BER_TYPE_BYTES>, but decodes the value as if it were a UTF-8 string
		526	(without validation!) and encodes a perl unicode string into a UTF-8 BER
		527	string.
		528
		529	=item C<BER_TYPE_UCS2>
		530
		531	Similar to C<BER_TYPE_UTF8>, but treats the BER value as UCS-2 encoded
		532	string.
		533
		534	=item C<BER_TYPE_UCS4>
		535
		536	Similar to C<BER_TYPE_UTF8>, but treats the BER value as UCS-4 encoded
		537	string.
		538
		539	=item C<BER_TYPE_INT>
		540
		541	Encodes and decodes a BER integer value to a perl integer scalar. This
		542	should correctly handle 64 bit signed and unsigned values.
		543
		544	=item C<BER_TYPE_OID>
		545
		546	Encodes and decodes an OBJECT IDENTIFIER into dotted form without leading
		547	dot, e.g. C<1.3.6.1.213>.
		548
		549	=item C<BER_TYPE_RELOID>
		550
		551	Same as C<BER_TYPE_OID> but uses relative object identifier
		552	encoding: ASN.1 has this hack of encoding the first two OID components
		553	into a single integer in a weird attempt to save an insignificant amount
		554	of space in an otherwise wasteful encoding, and relative OIDs are
		555	basically OIDs without this hack. The practical difference is that the
		556	second component of an OID can only have the values 1..40, while relative
		557	OIDs do not have this restriction.
		558
		559	=item C<BER_TYPE_NULL>
		560
		561	Decodes an C<ASN_NULL> value into C<undef>, and always encodes a
		562	C<ASN_NULL> type, regardless of the perl value.
		563
		564	=item C<BER_TYPE_BOOL>
		565
		566	Decodes an C<ASN_BOOLEAN> value into C<0> or C<1>, and encodes a perl
		567	boolean value into an C<ASN_BOOLEAN>.
		568
		569	=item C<BER_TYPE_REAL>
		570
		571	Decodes/encodes a BER real value. NOT IMPLEMENTED.
		572
		573	=item C<BER_TYPE_IPADDRESS>
		574
		575	Decodes/encodes a four byte string into an IPv4 dotted-quad address string
		576	in Perl. Given the obsolete nature of this type, this is a low-effort
		577	implementation that simply uses C<sprintf> and C<sscanf>-style conversion,
		578	so it won't handle all string forms supported by C<inet_aton> for example.
		579
		580	=item C<BER_TYPE_CROAK>
		581
		582	Always croaks when encountered during encoding or decoding - the
		583	default behaviour when encountering an unknown type is to treat it as
		584	C<BER_TYPE_BYTES>. When you don't want that but instead prefer a hard
		585	error for some types, then C<BER_TYPE_CROAK> is for you.
		586
		587	=back
		588
		589	=head2 Example Profile
		590
		591	The following creates a profile suitable for SNMP - it's exactly identical
		592	to the C<$Convert::BER::XS::SNMP_PROFILE> profile.
		593
		594	our $SNMP_PROFILE = new Convert::BER::XS::Profile;
		595
		596	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS);
		597	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT);
		598	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT);
		599	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT);
		600	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_IPADDRESS);
		601	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT);
		602
		603	=cut
		604
		605	our $DEFAULT_PROFILE = new Convert::BER::XS::Profile;
		606
		607	$DEFAULT_PROFILE->_set_default;
		608
		609	# additional SNMP application types
		610	our $SNMP_PROFILE = new Convert::BER::XS::Profile;
		611
		612	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS);
		613	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT);
		614	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT);
		615	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT);
		616	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_IPADDRESS);
		617	$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT);
318		618
319	1;	619	1;
320		620
321	=head2 BUGS / SHORTCOMINGs	621	=head2 LIMITATIONS/NOTES
322		622
323	This module does have a number of SNMPisms hardcoded, such as the SNMP	623	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	624	only when your perl supports those.
325	ever implemented, will come in a form similar to how L<JSON::XS> and	625
326	L<CBOR::XS> respresent things, namely with an object-oriented interface.	626	This module does not generally care about ranges, i.e. it will happily
		627	de-/encode 64 bit integers into an C<ASN_INTEGER> value, or a negative
		628	number into an C<SNMP_COUNTER64>.
		629
		630	OBJECT IDENTIFIEERs cannot have unlimited length, although the limit is
		631	much larger than e.g. the one imposed by SNMP or other protocols,a nd is
		632	about 4kB.
		633
		634	Indefinite length encoding is not supported.
		635
		636	Constructed strings are decoded just fine, but there should be a way to
		637	join them for convenience.
		638
		639	REAL values are not supported and will currently croak.
		640
		641	The encoder and decoder tend to accept more formats than should be
		642	strictly supported.
		643
		644	This module has undergone little to no testing so far.
		645
		646	=head2 ITHREADS SUPPORT
		647
		648	This module is unlikely to work when the (officially discouraged) ithreads
		649	are in use.
327		650
328	=head1 AUTHOR	651	=head1 AUTHOR
329		652
330	Marc Lehmann <schmorp@schmorp.de>	653	Marc Lehmann <schmorp@schmorp.de>
331	http://software.schmorp.de/pkg/Convert-BER-XS	654	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 1.33 by root, Sat Apr 20 17:23:21 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 1.33 by root, Sat Apr 20 17:23:21 2019 UTC