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Revision 1.14 by root, Sat Apr 20 01:31:07 2019 UTC vs.
Revision 1.27 by root, Sat Apr 20 15:27:28 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 12 # The above results in a data structure consisting of
13 # (class, tag, # constructed, data) 13 # (class, tag, # constructed, data)
14 # tuples. Below is such a message, SNMPv1 trap 14 # tuples. Below is such a message, SNMPv1 trap
15 # with a Cisco mac change notification. 15 # with a Cisco mac change notification.
16 # Did you know that Cisco is in the news almost 16 # Did you know that Cisco is in the news almost
17 # every week because # of some backdoor password 17 # every week because of some backdoor password
18 # or other extremely stupid security bug? 18 # or other extremely stupid security bug?
19 19
20 [ ASN_UNIVERSAL, ASN_SEQUENCE, 1, 20 [ ASN_UNIVERSAL, ASN_SEQUENCE, 1,
21 [ 21 [
22 [ ASN_UNIVERSAL, ASN_INTEGER32, 0, 0 ], # snmp version 1 22 [ ASN_UNIVERSAL, ASN_INTEGER, 0, 0 ], # snmp version 1
23 [ ASN_UNIVERSAL, 4, 0, "public" ], # community 23 [ ASN_UNIVERSAL, 4, 0, "public" ], # community
24 [ ASN_CONTEXT, 4, 1, # CHOICE, constructed - trap PDU 24 [ ASN_CONTEXT, 4, 1, # CHOICE, constructed - trap PDU
25 [ 25 [
26 [ 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
27 [ 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
28 [ ASN_UNIVERSAL, ASN_INTEGER32, 0, 6 ], # generic trap 28 [ ASN_UNIVERSAL, ASN_INTEGER, 0, 6 ], # generic trap
29 [ ASN_UNIVERSAL, ASN_INTEGER32, 0, 1 ], # specific trap 29 [ ASN_UNIVERSAL, ASN_INTEGER, 0, 1 ], # specific trap
30 [ ASN_APPLICATION, ASN_TIMETICKS, 0, 1817903850 ], # SNMP TimeTicks 30 [ ASN_APPLICATION, SNMP_TIMETICKS, 0, 1817903850 ], # SNMP TimeTicks
31 [ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # the varbindlist 31 [ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # the varbindlist
32 [ 32 [
33 [ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # a single varbind, "key value" pair 33 [ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # a single varbind, "key value" pair
34 [ 34 [
35 [ 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" ],
42 # let's decode it a bit with some helper functions 42 # let's decode it a bit with some helper functions
43 43
44 my $msg = ber_is_seq $ber 44 my $msg = ber_is_seq $ber
45 or die "SNMP message does not start with a sequence"; 45 or die "SNMP message does not start with a sequence";
46 46
47 ber_is $msg->[0], ASN_UNIVERSAL, ASN_INTEGER32, 0 47 ber_is $msg->[0], ASN_UNIVERSAL, ASN_INTEGER, 0
48 or die "SNMP message does not start with snmp version\n"; 48 or die "SNMP message does not start with snmp version\n";
49 49
50 # message is SNMP v1 or v2c? 50 # message is SNMP v1 or v2c?
51 if ($msg->[0][BER_DATA] == 0 || $msg->[0][BER_DATA] == 1) { 51 if ($msg->[0][BER_DATA] == 0 || $msg->[0][BER_DATA] == 1) {
52 52
55 my $trap = $msg->[2][BER_DATA]; 55 my $trap = $msg->[2][BER_DATA];
56 56
57 # check whether trap is a cisco mac notification mac changed message 57 # check whether trap is a cisco mac notification mac changed message
58 if ( 58 if (
59 (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
60 and (ber_is_i32 $trap->[2], 6) 60 and (ber_is_int $trap->[2], 6)
61 and (ber_is_i32 $trap->[3], 1) # mac changed msg 61 and (ber_is_int $trap->[3], 1) # mac changed msg
62 ) { 62 ) {
63 ... and so on 63 ... and so on
64 64
65 # 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
66 66
67 my $buf = ber_encode $ber; 67 my $buf = ber_encode $ber, $Convert::BER::XS::SNMP_PROFILE;
68 68
69=head1 DESCRIPTION 69=head1 DESCRIPTION
70 70
71WARNING: Before release 1.0, the API is not considered stable in any way. 71WARNING: Before release 1.0, the API is not considered stable in any way.
72 72
73This module implements a I<very> low level BER/DER en-/decoder. 73This module implements a I<very> low level BER/DER en-/decoder.
74 74
75If is tuned for low memory and high speed, while still maintaining some 75It is tuned for low memory and high speed, while still maintaining some
76level of user-friendlyness. 76level of user-friendlyness.
77 77
78Currently, not much is documented, as this is an initial release to 78=head2 EXPORT TAGS AND CONSTANTS
79reserve CPAN namespace, stay tuned for a few days. 79
80By default this module doesn't export any symbols, but if you don't want
81to break your keyboard, editor or eyesight with extremely long names, I
82recommend importing the C<:all> tag. Still, you can selectively import
83things.
84
85=over
86
87=item C<:all>
88
89All of the below. Really. Recommended for at least first steps, or if you
90don't care about a few kilobytes of wasted memory (and namespace).
91
92=item C<:const>
93
94All of the strictly ASN.1-related constants defined by this module, the
95same as C<:const_asn :const_index>. Notably, this does not contain
96C<:const_ber_type> and C<:const_snmp>.
97
98A good set to get everything you need to decode and match BER data would be
99C<:decode :const>.
100
101=item C<:const_index>
102
103The BER tuple array index constants:
104
105 BER_CLASS BER_TAG BER_CONSTRUCTED BER_DATA
106
107=item C<:const_asn>
108
109ASN class values (these are C<0>, C<1>, C<2> and C<3>, respectively -
110exactly thw two topmost bits from the identifier octet shifted 6 bits to
111the right):
112
113 ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE
114
115ASN tag values (some of which are aliases, such as C<ASN_OID>). Their
116numerical 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
127The 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
135Constants only relevant to SNMP. These are the tag values used by SNMP in
136the C<ASN_APPLICATION> namespace and have the exact numerical value as in
137BER/RFC 2578.
138
139 SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
140
141=item C<:decode>
142
143C<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
149C<ber_encode> and the construction helper functions:
150
151 ber_encode ber_int
152
153=back
80 154
81=head2 ASN.1/BER/DER/... BASICS 155=head2 ASN.1/BER/DER/... BASICS
82 156
83ASN.1 is a strange language that can be sed to describe protocols and 157ASN.1 is a strange language that can be used to describe protocols and
84data structures. It supports various mappings to JSON, XML, but most 158data structures. It supports various mappings to JSON, XML, but most
85importantly, to a various binary encodings such as BER, that is the topic 159importantly, to a various binary encodings such as BER, that is the topic
86of this module, and is used in SNMP or LDAP for example. 160of this module, and is used in SNMP, LDAP or X.509 for example.
87 161
88While ASN.1 defines a schema that is useful to interpret encoded data, 162While ASN.1 defines a schema that is useful to interpret encoded data,
89the BER encoding is actually somewhat self-describing: you might not know 163the BER encoding is actually somewhat self-describing: you might not know
90whether something is a string or a number or a sequence or something else, 164whether something is a string or a number or a sequence or something else,
91but you can nevertheless decode the overall structure, even if you end up 165but you can nevertheless decode the overall structure, even if you end up
92with just a binary blob for the actual value. 166with just a binary blob for the actual value.
93 167
94This works because BER values are tagged with a type and a namespace, 168This works because BER values are tagged with a type and a namespace,
95and also have a flag that says whther a value consists of subvalues (is 169and also have a flag that says whether a value consists of subvalues (is
96"constructed") or not (is "primitive"). 170"constructed") or not (is "primitive").
97 171
98Tags are simple integers, and ASN.1 defines a somewhat weird assortment of 172Tags are simple integers, and ASN.1 defines a somewhat weird assortment
99those - for example, you have 32 bit signed integers and 16(!) different 173of those - for example, you have one integers and 16(!) different
100string types, but there is no unsigned32 type for example. Different 174string types, but there is no Unsigned32 type for example. Different
101applications work around this in different ways, for example, SNMP defines 175applications work around this in different ways, for example, SNMP defines
102application-specific Gauge32, Counter32 and Unsigned32, which are mapped 176application-specific Gauge32, Counter32 and Unsigned32, which are mapped
103to two different tags: you can distinguish between Counter32 and the 177to two different tags: you can distinguish between Counter32 and the
104others, but not between Gause32 and Unsigned32, without the ASN.1 schema. 178others, but not between Gause32 and Unsigned32, without the ASN.1 schema.
105 179
110This module represents every BER value as a 4-element tuple (actually an 184This module represents every BER value as a 4-element tuple (actually an
111array-reference): 185array-reference):
112 186
113 [CLASS, TAG, CONSTRUCTED, DATA] 187 [CLASS, TAG, CONSTRUCTED, DATA]
114 188
189For 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
195
115To avoid non-descriptive hardcoded array index numbers, this module 196To avoid non-descriptive hardcoded array index numbers, this module
116defines symbolic constants to access these members: C<BER_CLASS>, 197defines symbolic constants to access these members: C<BER_CLASS>,
117C<BER_TAG>, C<BER_CONSTRUCTED> and C<BER_DATA>. 198C<BER_TAG>, C<BER_CONSTRUCTED> and C<BER_DATA>.
118 199
119Also, the first three members are integers with a little caveat: for 200Also, the first three members are integers with a little caveat: for
126 # the following is NOT legal: 207 # the following is NOT legal:
127 $ber->[BER_CLASS] = ASN_PRIVATE; # ERROR, CLASS/TAG/CONSTRUCTED are READ ONLY(!) 208 $ber->[BER_CLASS] = ASN_PRIVATE; # ERROR, CLASS/TAG/CONSTRUCTED are READ ONLY(!)
128 209
129 # but all of the following are fine: 210 # but all of the following are fine:
130 $ber->[BER_DATA] = "string"; 211 $ber->[BER_DATA] = "string";
131 $ber->[BER_DATA] = [ASN_UNIVERSAL, ASN_INTEGER32, 0, 123]; 212 $ber->[BER_DATA] = [ASN_UNIVERSAL, ASN_INTEGER, 0, 123];
132 @$ber = (ASN_APPLICATION, SNMP_TIMETICKS, 0, 1000); 213 @$ber = (ASN_APPLICATION, SNMP_TIMETICKS, 0, 1000);
133 214
134I<CLASS> is something like a namespace for I<TAG>s - there is the 215I<CLASS> is something like a namespace for I<TAG>s - there is the
135C<ASN_UNIVERSAL> namespace which defines tags common to all ASN.1 216C<ASN_UNIVERSAL> namespace which defines tags common to all ASN.1
136implementations, the C<ASN_APPLICATION> namespace which defines tags for 217implementations, the C<ASN_APPLICATION> namespace which defines tags for
137specific applications (for example, the SNMP C<Unsigned32> type is in this 218specific applications (for example, the SNMP C<Unsigned32> type is in this
138namespace), a special-purpose context namespace (C<ASN_CONTEXT>, used e.g. 219namespace), a special-purpose context namespace (C<ASN_CONTEXT>, used e.g.
139for C<CHOICE>) and a private namespace (C<ASN_PRIVATE>). 220for C<CHOICE>) and a private namespace (C<ASN_PRIVATE>).
140 221
141The meaning of the I<TAG> depends on the namespace, and defines a 222The meaning of the I<TAG> depends on the namespace, and defines a
142(partial) interpretation of the data value. For example, right now, SNMP 223(partial) interpretation of the data value. For example, SNMP defines
143application namespace knowledge ix hardcoded into this module, so it 224extra tags in the C<ASN_APPLICATION> namespace, and to take full advantage
144knows that SNMP C<Unsigned32> values need to be decoded into actual perl 225of these, you need to tell this module how to handle those via profiles.
145integers.
146 226
147The most common tags in the C<ASN_UNIVERSAL> namespace are 227The most common tags in the C<ASN_UNIVERSAL> namespace are
148C<ASN_INTEGER32>, C<ASN_BIT_STRING>, C<ASN_NULL>, C<ASN_OCTET_STRING>, 228C<ASN_INTEGER>, C<ASN_BIT_STRING>, C<ASN_NULL>, C<ASN_OCTET_STRING>,
149C<ASN_OBJECT_IDENTIFIER>, C<ASN_SEQUENCE>, C<ASN_SET> and 229C<ASN_OBJECT_IDENTIFIER>, C<ASN_SEQUENCE>, C<ASN_SET> and
150C<ASN_IA5_STRING>. 230C<ASN_IA5_STRING>.
151 231
152The most common tags in SNMP's C<ASN_APPLICATION> namespace 232The most common tags in SNMP's C<ASN_APPLICATION> namespace are
153are C<SNMP_IPADDRESS>, C<SNMP_COUNTER32>, C<SNMP_UNSIGNED32>, 233C<SNMP_COUNTER32>, C<SNMP_UNSIGNED32>, C<SNMP_TIMETICKS> and
154C<SNMP_TIMETICKS>, C<SNMP_OPAQUE> and C<SNMP_COUNTER64>. 234C<SNMP_COUNTER64>.
155 235
156The I<CONSTRUCTED> flag is really just a boolean - if it is false, the 236The I<CONSTRUCTED> flag is really just a boolean - if it is false,
157the value is "primitive" and contains no subvalues, kind of like a 237the value is "primitive" and contains no subvalues, kind of like a
158non-reference perl scalar. IF it is true, then the value is "constructed" 238non-reference perl scalar. If it is true, then the value is "constructed"
159which just means it contains a list of subvalues which this module will 239which just means it contains a list of subvalues which this module will
160en-/decode as BER tuples themselves. 240en-/decode as BER tuples themselves.
161 241
162The I<DATA> value is either a reference to an array of further tuples (if 242The I<DATA> value is either a reference to an array of further tuples (if
163the value is I<CONSTRUCTED>), some decoded representation of the value, 243the value is I<CONSTRUCTED>), some decoded representation of the value,
172 252
173=head2 DECODING AND ENCODING 253=head2 DECODING AND ENCODING
174 254
175=over 255=over
176 256
177=item $tuple = ber_decoded $bindata 257=item $tuple = ber_decoded $bindata[, $profile]
178 258
179Decodes binary BER data in C<$bindata> and returns the resulting BER 259Decodes binary BER data in C<$bindata> and returns the resulting BER
180tuple. Croaks on any decoding error, so the returned C<$tuple> is always 260tuple. Croaks on any decoding error, so the returned C<$tuple> is always
181valid. 261valid.
182 262
263How tags are interpreted is defined by the second argument, which must
264be a C<Convert::BER::XS::Profile> object. If it is missing, the default
265profile will be used (C<$Convert::BER::XS::DEFAULT_PROFILE>).
266
267In addition to rolling your own, this module provides a
268C<$Convert::BER::XS::SNMP_PROFILE> that knows about the additional SNMP
269types.
270
271Example: decode a BER blob using the default profile - SNMP values will be
272decided as raw strings.
273
274 $tuple = ber_decode $data;
275
276Example: as above, but use the provided SNMP profile.
277
278 $tuple = ber_encode $data, $Convert::BER::XS::SNMP_PROFILE;
279
183=item $bindata = ber_encode $tuple 280=item $bindata = ber_encode $tuple[, $profile]
184 281
185Encodes the BER tuple into a BER/DER data structure. 282Encodes the BER tuple into a BER/DER data structure. AS with
283Cyber_decode>, an optional profile can be given.
186 284
187=back 285=back
188 286
189=head2 HELPER FUNCTIONS 287=head2 HELPER FUNCTIONS
190 288
191Working with a 4-tuple for every value can be annoying. Or, rather, I<is> 289Working with a 4-tuple for every value can be annoying. Or, rather, I<is>
192annoying. To reduce this a bit, this module defines a number of helper 290annoying. To reduce this a bit, this module defines a number of helper
193functions, both to match BER tuples and to conmstruct BER tuples: 291functions, both to match BER tuples and to construct BER tuples:
194 292
195=head3 MATCH HELPERS 293=head3 MATCH HELPERS
196 294
197Thse functions accept a BER tuple as first argument and either paertially 295These functions accept a BER tuple as first argument and either partially
198or fully match it. They often come in two forms, one which exactly matches 296or fully match it. They often come in two forms, one which exactly matches
199a value, and one which only matches the type and returns the value. 297a value, and one which only matches the type and returns the value.
200 298
201They do check whether valid tuples are passed in and croak otherwise. As 299They do check whether valid tuples are passed in and croak otherwise. As
202a ease-of-use exception, they usually also accept C<undef> instead of a 300a ease-of-use exception, they usually also accept C<undef> instead of a
203tuple reference. in which case they silently fail to match. 301tuple reference, in which case they silently fail to match.
204 302
205=over 303=over
206 304
207=item $bool = ber_is $tuple, $class, $tag, $constructed, $data 305=item $bool = ber_is $tuple, $class, $tag, $constructed, $data
208 306
209This takes a BER C<$tuple> and matches its elements agains the privded 307This takes a BER C<$tuple> and matches its elements against the provided
210values, all of which are optional - values that are either missing or 308values, all of which are optional - values that are either missing or
211C<undef> will be ignored, the others will be matched exactly (e.g. as if 309C<undef> will be ignored, the others will be matched exactly (e.g. as if
212you used C<==> or C<eq> (for C<$data>)). 310you used C<==> or C<eq> (for C<$data>)).
213 311
214Some examples: 312Some examples:
217 orf die "tuple is not an ASN SEQUENCE"; 315 orf die "tuple is not an ASN SEQUENCE";
218 316
219 ber_is $tuple, ASN_UNIVERSAL, ASN_NULL 317 ber_is $tuple, ASN_UNIVERSAL, ASN_NULL
220 or die "tuple is not an ASN NULL value"; 318 or die "tuple is not an ASN NULL value";
221 319
222 ber_is $tuple, ASN_UNIVERSAL, ASN_INTEGER32, 0, 50 320 ber_is $tuple, ASN_UNIVERSAL, ASN_INTEGER, 0, 50
223 or die "BER integer must be 50"; 321 or die "BER integer must be 50";
224 322
225=item $seq = ber_is_seq $tuple 323=item $seq = ber_is_seq $tuple
226 324
227Returns the sequence members (the array of subvalues) if the C<$tuple> is 325Returns the sequence members (the array of subvalues) if the C<$tuple> is
234 my $snmp = ber_is_seq $ber 332 my $snmp = ber_is_seq $ber
235 or die "SNMP packet invalid: does not start with SEQUENCE"; 333 or die "SNMP packet invalid: does not start with SEQUENCE";
236 334
237 # now we know $snmp is a sequence, so decode the SNMP version 335 # now we know $snmp is a sequence, so decode the SNMP version
238 336
239 my $version = ber_is_i32 $snmp->[0] 337 my $version = ber_is_int $snmp->[0]
240 or die "SNMP packet invalid: does not start with version number"; 338 or die "SNMP packet invalid: does not start with version number";
241 339
242=item $bool = ber_is_i32 $tuple, $i32 340=item $bool = ber_is_int $tuple, $int
243 341
244Returns a true value if the C<$tuple> represents an ASN INTEGER32 with 342Returns a true value if the C<$tuple> represents an ASN INTEGER with
245the value C<$i32>. 343the value C<$int>.
246 344
247=item $i32 = ber_is_i32 $tuple 345=item $int = ber_is_int $tuple
248 346
249Returns true (and extracts the integer value) if the C<$tuple> is an ASN 347Returns true (and extracts the integer value) if the C<$tuple> is an
250INTEGER32. For C<0>, this function returns a special value that is 0 but 348C<ASN_INTEGER>. For C<0>, this function returns a special value that is 0
251true. 349but true.
252 350
253=item $bool = ber_is_oid $tuple, $oid_string 351=item $bool = ber_is_oid $tuple, $oid_string
254 352
255Returns true if the C<$tuple> represents an ASN_OBJECT_IDENTIFIER 353Returns true if the C<$tuple> represents an ASN_OBJECT_IDENTIFIER
256that exactly matches C<$oid_string>. Example: 354that exactly matches C<$oid_string>. Example:
267 365
268=head3 CONSTRUCTION HELPERS 366=head3 CONSTRUCTION HELPERS
269 367
270=over 368=over
271 369
272=item $tuple = ber_i32 $value 370=item $tuple = ber_int $value
273 371
274Constructs a new C<ASN_INTEGER32> tuple. 372Constructs a new C<ASN_INTEGER> tuple.
275 373
276=back 374=back
277 375
278=head2 RELATIONSHIP TO L<Convert::BER> and L<Convert::ASN1> 376=head2 RELATIONSHIP TO L<Convert::BER> and L<Convert::ASN1>
279 377
292use Exporter qw(import); 390use Exporter qw(import);
293 391
294our $VERSION; 392our $VERSION;
295 393
296BEGIN { 394BEGIN {
297 $VERSION = 0.7; 395 $VERSION = 0.8;
298 XSLoader::load __PACKAGE__, $VERSION; 396 XSLoader::load __PACKAGE__, $VERSION;
299} 397}
300 398
301our %EXPORT_TAGS = ( 399our %EXPORT_TAGS = (
302 const => [qw( 400 const_index => [qw(
303 BER_CLASS BER_TAG BER_CONSTRUCTED BER_DATA 401 BER_CLASS BER_TAG BER_CONSTRUCTED BER_DATA
304 402 )],
403 const_asn => [qw(
305 ASN_BOOLEAN ASN_INTEGER32 ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER 404 ASN_BOOLEAN ASN_INTEGER ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER
306 ASN_OBJECT_DESCRIPTOR ASN_OID ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED 405 ASN_OBJECT_DESCRIPTOR ASN_OID ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED
307 ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING 406 ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING
308 ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING 407 ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING
309 ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING 408 ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING
310 ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING 409 ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING
311 410
312 ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE 411 ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE
313 412 )],
413 const_ber_type => [qw(
314 BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT 414 BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT
315 BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL 415 BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL
316 BER_TYPE_IPADDRESS BER_TYPE_CROAK 416 BER_TYPE_IPADDRESS BER_TYPE_CROAK
317 )], 417 )],
318 const_snmp => [qw( 418 const_snmp => [qw(
319 SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64 419 SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
320 )], 420 )],
421 decode => [qw(
422 ber_decode
423 ber_is ber_is_seq ber_is_int ber_is_oid
424 )],
321 encode => [qw( 425 encode => [qw(
322 ber_decode
323 ber_is ber_is_seq ber_is_i32 ber_is_oid
324 )],
325 decode => [qw(
326 ber_encode 426 ber_encode
327 ber_i32 427 ber_int
328 )], 428 )],
329); 429);
330 430
331our @EXPORT_OK = map @$_, values %EXPORT_TAGS; 431our @EXPORT_OK = map @$_, values %EXPORT_TAGS;
332 432
333$EXPORT_TAGS{all} = \@EXPORT_OK; 433$EXPORT_TAGS{all} = \@EXPORT_OK;
434$EXPORT_TAGS{const} = [map @{ $EXPORT_TAGS{$_} }, qw(const_index const_asn)];
334 435
335=head1 PROFILES 436=head1 PROFILES
336 437
337While any BER data can be correctly encoded and decoded out of the box, it 438While any BER data can be correctly encoded and decoded out of the box, it
338can be inconvenient to have to manually decode some values into a "better" 439can be inconvenient to have to manually decode some values into a "better"
347 448
348The default profile supports the standard ASN.1 types, but no 449The default profile supports the standard ASN.1 types, but no
349application-specific ones. This means that class/tag combinations not in 450application-specific ones. This means that class/tag combinations not in
350the base set of ASN.1 are decoded into their raw octet strings. 451the base set of ASN.1 are decoded into their raw octet strings.
351 452
352C<Convert::BER::XS> defines two profile variables you cna use out of the box: 453C<Convert::BER::XS> defines two profile variables you can use out of the box:
353 454
354=over 455=over
355 456
356=item C<$Convert::BER::XS::DEFAULT_PROFILE> 457=item C<$Convert::BER::XS::DEFAULT_PROFILE>
357 458
358This is the default profile, i.e. the profile that is used when no 459This is the default profile, i.e. the profile that is used when no
359profile is specified for de-/encoding. 460profile is specified for de-/encoding.
360 461
361You cna modify it, but remember that this modifies the defaults for all 462You can modify it, but remember that this modifies the defaults for all
362callers that rely on the defauit profile. 463callers that rely on the default profile.
363 464
364=item C<$Convert::BER::XS::SNMP_PROFILE> 465=item C<$Convert::BER::XS::SNMP_PROFILE>
365 466
366A profile with mappings for SNMP-specific application tags added. This is 467A profile with mappings for SNMP-specific application tags added. This is
367useful when de-/encoding SNMP data. 468useful when de-/encoding SNMP data.
368 469
369Example: 470Example:
471
370 $ber = ber_decode $data, $Convert::BER::XS::SNMP_PROFILE; 472 $ber = ber_decode $data, $Convert::BER::XS::SNMP_PROFILE;
371 473
372=back 474=back
373 475
374=head2 The Convert::BER::XS::Profile class 476=head2 The Convert::BER::XS::Profile class
387 489
388Note that currently, the mapping is stored in a flat array, so large 490Note that currently, the mapping is stored in a flat array, so large
389values of C<$tag> will consume large amounts of memory. 491values of C<$tag> will consume large amounts of memory.
390 492
391Example: 493Example:
494
392 $profile = new Convert::BER::XS::Profile; 495 $profile = new Convert::BER::XS::Profile;
393 $profile->set (ASN_APPLICATION, SNMP_COUNTER32, BER_TYPE_INT); 496 $profile->set (ASN_APPLICATION, SNMP_COUNTER32, BER_TYPE_INT);
394 $ber = ber_decode $data, $profile; 497 $ber = ber_decode $data, $profile;
395 498
396=item $type = $profile->get ($class, $tag) 499=item $type = $profile->get ($class, $tag)
438Encodes and decodes an OBJECT IDENTIFIER into dotted form without leading 541Encodes and decodes an OBJECT IDENTIFIER into dotted form without leading
439dot, e.g. C<1.3.6.1.213>. 542dot, e.g. C<1.3.6.1.213>.
440 543
441=item C<BER_TYPE_RELOID> 544=item C<BER_TYPE_RELOID>
442 545
443Same as C<BER_TYPE_OID> but uses relative OID encoding: ASN.1 has this 546Same as C<BER_TYPE_OID> but uses relative object identifier
444hack of encoding the first two OID components into a single integer in a 547encoding: ASN.1 has this hack of encoding the first two OID components
445weird attempt to save an insignificant amount of space in an otherwise 548into a single integer in a weird attempt to save an insignificant amount
446wasteful encoding, and relative OIDs are basically OIDs without this 549of space in an otherwise wasteful encoding, and relative OIDs are
447hack. The practical difference is that the second component of an OID 550basically OIDs without this hack. The practical difference is that the
448can only have the values 1..40, while relative OIDs do not have this 551second component of an OID can only have the values 1..40, while relative
449restriction. 552OIDs do not have this restriction.
450 553
451=item C<BER_TYPE_NULL> 554=item C<BER_TYPE_NULL>
452 555
453Decodes an C<ASN_NULL> value into C<undef>, and always encodes a 556Decodes an C<ASN_NULL> value into C<undef>, and always encodes a
454C<ASN_NULL> type, regardless of the perl value. 557C<ASN_NULL> type, regardless of the perl value.
462 565
463Decodes/encodes a BER real value. NOT IMPLEMENTED. 566Decodes/encodes a BER real value. NOT IMPLEMENTED.
464 567
465=item C<BER_TYPE_IPADDRESS> 568=item C<BER_TYPE_IPADDRESS>
466 569
467Decodes/encodes a four byte string into an IOv4 dotted-quad address string 570Decodes/encodes a four byte string into an IPv4 dotted-quad address string
468in perl. Given ther obsolete nature of this type, this is a low-effort 571in Perl. Given the obsolete nature of this type, this is a low-effort
469implementation that simply uses C<sprintf> and C<sscanf>-style conversion, 572implementation that simply uses C<sprintf> and C<sscanf>-style conversion,
470so it won't handle all string forms supported by C<inet_aton>. 573so it won't handle all string forms supported by C<inet_aton> for example.
471 574
472=item C<BER_TYPE_CROAK> 575=item C<BER_TYPE_CROAK>
473 576
474Always croaks when encountered during encoding or decoding - the 577Always croaks when encountered during encoding or decoding - the
475default behaviour when encountering an unknown type is to treat it as 578default behaviour when encountering an unknown type is to treat it as
476C<BER_TYPE_BYTES>. When you don't want that but instead prefer a hard 579C<BER_TYPE_BYTES>. When you don't want that but instead prefer a hard
477error for some types, then CyBER_TYPE_CROAK> is for you. 580error for some types, then C<BER_TYPE_CROAK> is for you.
478 581
479=back 582=back
480 583
481=cut 584=cut
482 585
483our $DEFAULT_PROFILE = new Convert::BER::XS::Profile; 586our $DEFAULT_PROFILE = new Convert::BER::XS::Profile;
484our $SNMP_PROFILE = new Convert::BER::XS::Profile; 587our $SNMP_PROFILE = new Convert::BER::XS::Profile;
485 588
589# additional SNMP application types
486$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS); 590$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS);
487$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT); 591$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT);
488$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT); 592$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT);
489$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT); 593$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT);
490$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_IPADDRESS); 594$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_IPADDRESS);
492 596
493$DEFAULT_PROFILE->_set_default; 597$DEFAULT_PROFILE->_set_default;
494 598
4951; 5991;
496 600
497=head2 LIMITATIONS 601=head2 LIMITATIONS/NOTES
498 602
499This module can only en-/decode 64 bit signed and unsigned integers, and 603This module can only en-/decode 64 bit signed and unsigned integers, and
500only when your perl supports those. 604only when your perl supports those.
501 605
606This module does not generally care about ranges, i.e. it will happily
607de-/encode 64 bit integers into an C<ASN_INTEGER> value, or a negative
608number into an C<SNMP_COUNTER64>.
609
502OBJECT IDENTIFIEERS cannot have unlimited length, although the limit is 610OBJECT IDENTIFIEERs cannot have unlimited length, although the limit is
503much larger than e.g. the one imposed by SNMP or other protocols. 611much larger than e.g. the one imposed by SNMP or other protocols,a nd is
612about 4kB.
504 613
505REAL values are not supported and will croak. 614REAL values are not supported and will currently croak.
506 615
507This module has undergone little to no testing so far. 616This module has undergone little to no testing so far.
617
618=head2 ITHREADS SUPPORT
619
620This module is unlikely to work when the (officially discouraged) ithreads
621are in use.
508 622
509=head1 AUTHOR 623=head1 AUTHOR
510 624
511 Marc Lehmann <schmorp@schmorp.de> 625 Marc Lehmann <schmorp@schmorp.de>
512 http://software.schmorp.de/pkg/Convert-BER-XS 626 http://software.schmorp.de/pkg/Convert-BER-XS

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