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Revision 1.29 by root, Sat Apr 20 15:39:13 2019 UTC vs.
Revision 1.63 by root, Wed Mar 3 05:30:23 2021 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 # decode a binary BER data structure using the SNMP profile
9 my $ber = ber_decode $buf, $Convert::BER::XS::SNMP_PROFILE 10 my $ber = ber_decode $buf, $Convert::BER::XS::SNMP_PROFILE
10 or die "unable to decode SNMP message"; 11 or die "unable to decode SNMP message";
11 12
12 # The above results in a data structure consisting of 13 # The above results in a data structure consisting of
13 # (class, tag, flags, data) 14 # (class, tag, flags, data)
14 # tuples. Below is such a message, SNMPv1 trap 15 # tuples. Below is such a message, an SNMPv1 trap
15 # with a Cisco mac change notification. 16 # with a Cisco mac change notification.
16 # Did you know that Cisco is in the news almost 17 # (Did you know that Cisco is in the news almost
17 # every week because of some backdoor password 18 # every week because of some backdoor password
18 # or other extremely stupid security bug? 19 # or other extremely stupid security bug?)
19 20
20 [ ASN_UNIVERSAL, ASN_SEQUENCE, 1, 21 [ ASN_UNIVERSAL, ASN_SEQUENCE, 1,
21 [ 22 [
22 [ ASN_UNIVERSAL, ASN_INTEGER, 0, 0 ], # snmp version 1 23 [ ASN_UNIVERSAL, ASN_INTEGER, 0, 0 ], # snmp version 1
23 [ ASN_UNIVERSAL, 4, 0, "public" ], # community 24 [ ASN_UNIVERSAL, 4, 0, "public" ], # community
37 ] 38 ]
38 ] 39 ]
39 ], 40 ],
40 ... 41 ...
41 42
43 # let's dump the above structure, for debugging
44 ber_dump $ber, $Convert::BER::XS::SNMP_PROFILE;
45
42 # let's decode it a bit with some helper functions 46 # let's decode it a bit with some helper functions.
43 47 # first check whether it starts with a sequence
44 my $msg = ber_is_seq $ber 48 my $msg = ber_is_seq $ber
45 or die "SNMP message does not start with a sequence"; 49 or die "SNMP message does not start with a sequence";
46 50
51 # then check if its some kind of integer
47 ber_is $msg->[0], ASN_UNIVERSAL, ASN_INTEGER, 0 52 ber_is $msg->[0], ASN_UNIVERSAL, ASN_INTEGER, 0
48 or die "SNMP message does not start with snmp version\n"; 53 or die "SNMP message does not start with snmp version";
49 54
50 # message is SNMP v1 or v2c? 55 # message is SNMP v1 or v2c?
51 if ($msg->[0][BER_DATA] == 0 || $msg->[0][BER_DATA] == 1) { 56 if ($msg->[0][BER_DATA] == 0 || $msg->[0][BER_DATA] == 1) {
52 57
53 # message is v1 trap? 58 # message is v1 trap?
61 and (ber_is_int $trap->[3], 1) # mac changed msg 66 and (ber_is_int $trap->[3], 1) # mac changed msg
62 ) { 67 ) {
63 ... and so on 68 ... and so on
64 69
65 # finally, let's encode it again and hope it results in the same bit pattern 70 # finally, let's encode it again and hope it results in the same bit pattern
66
67 my $buf = ber_encode $ber, $Convert::BER::XS::SNMP_PROFILE; 71 my $buf = ber_encode $ber, $Convert::BER::XS::SNMP_PROFILE;
68 72
69=head1 DESCRIPTION 73=head1 DESCRIPTION
70
71WARNING: Before release 1.0, the API is not considered stable in any way.
72 74
73This module implements a I<very> low level BER/DER en-/decoder. 75This module implements a I<very> low level BER/DER en-/decoder.
74 76
75It is tuned for low memory and high speed, while still maintaining some 77It is tuned for low memory and high speed, while still maintaining some
76level of user-friendlyness. 78level of user-friendlyness.
105 BER_CLASS BER_TAG BER_FLAGS BER_DATA 107 BER_CLASS BER_TAG BER_FLAGS BER_DATA
106 108
107=item C<:const_asn> 109=item C<:const_asn>
108 110
109ASN class values (these are C<0>, C<1>, C<2> and C<3>, respectively - 111ASN 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 112exactly the two topmost bits from the identifier octet shifted 6 bits to
111the right): 113the right):
112 114
113 ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE 115 ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE
114 116
115ASN tag values (some of which are aliases, such as C<ASN_OID>). Their 117ASN 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. 118numerical value corresponds exactly to the numbers used in BER/X.690.
117 119
118 ASN_BOOLEAN ASN_INTEGER ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER 120 ASN_BOOLEAN ASN_INTEGER ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OID
119 ASN_OBJECT_DESCRIPTOR ASN_OID ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED 121 ASN_OBJECT_IDENTIFIER ASN_OBJECT_DESCRIPTOR ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED
120 ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING 122 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 123 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 124 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 125 ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING
124 126
134 136
135Constants only relevant to SNMP. These are the tag values used by SNMP in 137Constants 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 138the C<ASN_APPLICATION> namespace and have the exact numerical value as in
137BER/RFC 2578. 139BER/RFC 2578.
138 140
139 SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64 141 SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_GAUGE32
142 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
140 143
141=item C<:decode> 144=item C<:decode>
142 145
143C<ber_decode> and the match helper functions: 146C<ber_decode> and the match helper functions:
144 147
148 ber_decode ber-decode_prefix
145 ber_decode ber_is ber_is_seq ber_is_int ber_is_oid 149 ber_is ber_is_seq ber_is_int ber_is_oid
150 ber_dump
146 151
147=item C<:encode> 152=item C<:encode>
148 153
149C<ber_encode> and the construction helper functions: 154C<ber_encode> and the construction helper functions:
150 155
151 ber_encode ber_int 156 ber_encode
157 ber_int
152 158
153=back 159=back
154 160
155=head2 ASN.1/BER/DER/... BASICS 161=head2 ASN.1/BER/DER/... BASICS
156 162
168This works because BER values are tagged with a type and a namespace, 174This works because BER values are tagged with a type and a namespace,
169and also have a flag that says whether a value consists of subvalues (is 175and also have a flag that says whether a value consists of subvalues (is
170"constructed") or not (is "primitive"). 176"constructed") or not (is "primitive").
171 177
172Tags are simple integers, and ASN.1 defines a somewhat weird assortment 178Tags are simple integers, and ASN.1 defines a somewhat weird assortment
173of those - for example, you have one integers and 16(!) different 179of those - for example, you have one integer but 16(!) different
174string types, but there is no Unsigned32 type for example. Different 180string types, but there is no Unsigned32 type for example. Different
175applications work around this in different ways, for example, SNMP defines 181applications work around this in different ways, for example, SNMP defines
176application-specific Gauge32, Counter32 and Unsigned32, which are mapped 182application-specific Gauge32, Counter32 and Unsigned32, which are mapped
177to two different tags: you can distinguish between Counter32 and the 183to two different tags: you can distinguish between Counter32 and the
178others, but not between Gause32 and Unsigned32, without the ASN.1 schema. 184others, but not between Gause32 and Unsigned32, without the ASN.1 schema.
252 258
253=head2 DECODING AND ENCODING 259=head2 DECODING AND ENCODING
254 260
255=over 261=over
256 262
257=item $tuple = ber_decoded $bindata[, $profile] 263=item $tuple = ber_decode $bindata[, $profile]
258 264
259Decodes binary BER data in C<$bindata> and returns the resulting BER 265Decodes binary BER data in C<$bindata> and returns the resulting BER
260tuple. Croaks on any decoding error, so the returned C<$tuple> is always 266tuple. Croaks on any decoding error, so the returned C<$tuple> is always
261valid. 267valid.
262 268
275 281
276Example: as above, but use the provided SNMP profile. 282Example: as above, but use the provided SNMP profile.
277 283
278 $tuple = ber_encode $data, $Convert::BER::XS::SNMP_PROFILE; 284 $tuple = ber_encode $data, $Convert::BER::XS::SNMP_PROFILE;
279 285
286=item ($tuple, $bytes) = ber_decode_prefix $bindata[, $profile]
287
288Works like C<ber_decode>, except it doesn't croak when there is data after
289the BER data, but instead returns the decoded value and the number of
290bytes it decoded.
291
292This is useful when you have BER data at the start of a buffer and other
293data after, and you need to find the length.
294
295Also, since BER is self-delimited, this can be used to decode multiple BER
296values joined together.
297
280=item $bindata = ber_encode $tuple[, $profile] 298=item $bindata = ber_encode $tuple[, $profile]
281 299
282Encodes the BER tuple into a BER/DER data structure. AS with 300Encodes the BER tuple into a BER/DER data structure. As with
283Cyber_decode>, an optional profile can be given. 301Cyber_decode>, an optional profile can be given.
284 302
285The encoded data should be both BER and DER ("shortest form") compliant 303The encoded data should be both BER and DER ("shortest form") compliant
286unless the input says otherwise (e.g. it uses constructed strings). 304unless the input says otherwise (e.g. it uses constructed strings).
287 305
390use common::sense; 408use common::sense;
391 409
392use XSLoader (); 410use XSLoader ();
393use Exporter qw(import); 411use Exporter qw(import);
394 412
413use Carp ();
414
395our $VERSION; 415our $VERSION;
396 416
397BEGIN { 417BEGIN {
398 $VERSION = 0.8; 418 $VERSION = 1.21;
399 XSLoader::load __PACKAGE__, $VERSION; 419 XSLoader::load __PACKAGE__, $VERSION;
400} 420}
401 421
402our %EXPORT_TAGS = ( 422our %EXPORT_TAGS = (
403 const_index => [qw( 423 const_index => [qw(
404 BER_CLASS BER_TAG BER_FLAGS BER_DATA 424 BER_CLASS BER_TAG BER_FLAGS BER_DATA
405 )], 425 )],
426 const_asn_class => [qw(
427 ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE
428 )],
406 const_asn => [qw( 429 const_asn_tag => [qw(
407 ASN_BOOLEAN ASN_INTEGER ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER 430 ASN_BOOLEAN ASN_INTEGER ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OID ASN_OBJECT_IDENTIFIER
408 ASN_OBJECT_DESCRIPTOR ASN_OID ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED 431 ASN_OBJECT_DESCRIPTOR ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED
409 ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING 432 ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING
410 ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING 433 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 434 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 435 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 )], 436 )],
416 const_ber_type => [qw( 437 const_ber_type => [qw(
417 BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT 438 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 439 BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL
419 BER_TYPE_IPADDRESS BER_TYPE_CROAK 440 BER_TYPE_IPADDRESS BER_TYPE_CROAK
420 )], 441 )],
421 const_snmp => [qw( 442 const_snmp => [qw(
422 SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64 443 SNMP_IPADDRESS SNMP_COUNTER32 SNMP_GAUGE32 SNMP_UNSIGNED32
444 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64
423 )], 445 )],
424 decode => [qw( 446 decode => [qw(
425 ber_decode 447 ber_decode ber_decode_prefix
426 ber_is ber_is_seq ber_is_int ber_is_oid 448 ber_is ber_is_seq ber_is_int ber_is_oid
449 ber_dump
427 )], 450 )],
428 encode => [qw( 451 encode => [qw(
429 ber_encode 452 ber_encode
430 ber_int 453 ber_int
431 )], 454 )],
432); 455);
433 456
434our @EXPORT_OK = map @$_, values %EXPORT_TAGS; 457our @EXPORT_OK = map @$_, values %EXPORT_TAGS;
435 458
436$EXPORT_TAGS{all} = \@EXPORT_OK; 459$EXPORT_TAGS{all} = \@EXPORT_OK;
460$EXPORT_TAGS{const_asn} = [map @{ $EXPORT_TAGS{$_} }, qw(const_asn_class const_asn_tag)];
437$EXPORT_TAGS{const} = [map @{ $EXPORT_TAGS{$_} }, qw(const_index const_asn)]; 461$EXPORT_TAGS{const} = [map @{ $EXPORT_TAGS{$_} }, qw(const_index const_asn)];
462
463our $DEFAULT_PROFILE = new Convert::BER::XS::Profile;
464
465$DEFAULT_PROFILE->_set_default;
466
467# additional SNMP application types
468our $SNMP_PROFILE = new Convert::BER::XS::Profile;
469
470$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS);
471$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT);
472$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT);
473$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT);
474$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT);
475
476# decodes REAL values according to ECMA-63
477# this is pretty strict, except it doesn't catch -0.
478# I don't have access to ISO 6093 (or BS 6727, or ANSI X.3-42)), so this is all guesswork.
479sub _decode_real_decimal {
480 my ($format, $val) = @_;
481
482 $val =~ y/,/./; # probably not in ISO-6093
483
484 if ($format == 1) {
485 $val =~ /^ \ * [+-]? [0-9]+ \z/x
486 or Carp::croak "BER_TYPE_REAL NR1 value not in NR1 format ($val) (X.690 8.5.8)";
487 } elsif ($format == 2) {
488 $val =~ /^ \ * [+-]? (?: [0-9]+\.[0-9]* | [0-9]*\.[0-9]+ ) \z/x
489 or Carp::croak "BER_TYPE_REAL NR2 value not in NR2 format ($val) (X.690 8.5.8)";
490 } elsif ($format == 3) {
491 $val =~ /^ \ * [+-] (?: [0-9]+\.[0-9]* | [0-9]*\.[0-9]+ ) [eE] [+-]? [0-9]+ \z/x
492 or Carp::croak "BER_TYPE_REAL NR3 value not in NR3 format ($val) (X.690 8.5.8)";
493 } else {
494 Carp::croak "BER_TYPE_REAL invalid decimal numerical representation format $format";
495 }
496
497 $val
498}
499
500# this is a mess, but perl's support for floating point formatting is nearly nonexistant
501sub _encode_real_decimal {
502 my ($val, $nvdig) = @_;
503
504 $val = sprintf "%.*G", $nvdig + 1, $val;
505
506 if ($val =~ /E/) {
507 $val =~ s/E(?=[^+-])/E+/;
508 $val =~ s/E/.E/ if $val !~ /\./;
509 $val =~ s/^/+/ unless $val =~ /^-/;
510
511 return "\x03$val" # NR3
512 }
513
514 $val =~ /\./
515 ? "\x02$val" # NR2
516 : "\x01$val" # NR1
517}
518
519=head2 DEBUGGING
520
521To aid debugging, you can call the C<ber_dump> function to print a "nice"
522representation to STDOUT.
523
524=over
525
526=item ber_dump $tuple[, $profile[, $prefix]]
527
528In addition to specifying the BER C<$tuple> to dump, you can also specify
529a C<$profile> and a C<$prefix> string that is printed in front of each line.
530
531If C<$profile> is C<$Convert::BER::XS::SNMP_PROFILE>, then C<ber_dump>
532will try to improve its output for SNMP data.
533
534The output usually contains three columns, the "human readable" tag, the
535BER type used to decode it, and the data value.
536
537This function is somewhat slow and uses a number of heuristics and tricks,
538so it really is only suitable for debug prints.
539
540Example output:
541
542 SEQUENCE
543 | OCTET_STRING bytes 800063784300454045045400000001
544 | OCTET_STRING bytes
545 | CONTEXT (7) CONSTRUCTED
546 | | INTEGER int 1058588941
547 | | INTEGER int 0
548 | | INTEGER int 0
549 | | SEQUENCE
550 | | | SEQUENCE
551 | | | | OID oid 1.3.6.1.2.1.1.3.0
552 | | | | TIMETICKS int 638085796
553
554=back
555
556=cut
557
558# reverse enum, very slow and ugly hack
559sub _re {
560 my ($export_tag, $value) = @_;
561
562 for my $symbol (@{ $EXPORT_TAGS{$export_tag} }) {
563 $value == eval $symbol
564 and return $symbol;
565 }
566
567 "($value)"
568}
569
570sub _ber_dump {
571 my ($ber, $profile, $indent) = @_;
572
573 if (my $seq = ber_is_seq $ber) {
574 printf "%sSEQUENCE\n", $indent;
575 &_ber_dump ($_, $profile, "$indent| ")
576 for @$seq;
577 } else {
578 my $asn = $ber->[BER_CLASS] == ASN_UNIVERSAL;
579
580 my $class = _re const_asn_class => $ber->[BER_CLASS];
581 my $tag = $asn ? _re const_asn_tag => $ber->[BER_TAG] : $ber->[BER_TAG];
582 my $type = _re const_ber_type => $profile->get ($ber->[BER_CLASS], $ber->[BER_TAG]);
583 my $data = $ber->[BER_DATA];
584
585 if ($profile == $SNMP_PROFILE and $ber->[BER_CLASS] == ASN_APPLICATION) {
586 $tag = _re const_snmp => $ber->[BER_TAG];
587 } elsif (!$asn) {
588 $tag = "$class ($tag)";
589 }
590
591 $class =~ s/^ASN_//;
592 $tag =~ s/^(ASN_|SNMP_)//;
593 $type =~ s/^BER_TYPE_//;
594
595 if ($ber->[BER_FLAGS]) {
596 printf "$indent%-16.16s\n", $tag;
597 &_ber_dump ($_, $profile, "$indent| ")
598 for @$data;
599 } else {
600 if ($data =~ y/\x20-\x7e//c / (length $data || 1) > 0.2 or $data =~ /\x00./s) {
601 # assume binary
602 $data = unpack "H*", $data;
603 } else {
604 $data =~ s/[^\x20-\x7e]/./g;
605 $data = "\"$data\"" if $tag =~ /string/i || !length $data;
606 }
607
608 substr $data, 40, 1e9, "..." if 40 < length $data;
609
610 printf "$indent%-16.16s %-6.6s %s\n", $tag, lc $type, $data;
611 }
612 }
613}
614
615sub ber_dump($;$$) {
616 _ber_dump $_[0], $_[1] || $DEFAULT_PROFILE, $_[2];
617}
438 618
439=head1 PROFILES 619=head1 PROFILES
440 620
441While any BER data can be correctly encoded and decoded out of the box, it 621While any BER data can be correctly encoded and decoded out of the box, it
442can be inconvenient to have to manually decode some values into a "better" 622can be inconvenient to have to manually decode some values into a "better"
468=item C<$Convert::BER::XS::SNMP_PROFILE> 648=item C<$Convert::BER::XS::SNMP_PROFILE>
469 649
470A profile with mappings for SNMP-specific application tags added. This is 650A profile with mappings for SNMP-specific application tags added. This is
471useful when de-/encoding SNMP data. 651useful when de-/encoding SNMP data.
472 652
653The L<Example Profile> section, below, shows how this profile is being
654constructed.
655
473Example: 656Example:
474 657
475 $ber = ber_decode $data, $Convert::BER::XS::SNMP_PROFILE; 658 $ber = ber_decode $data, $Convert::BER::XS::SNMP_PROFILE;
476 659
477=back 660=back
503 686
504Returns the BER type mapped to the given C<$class>/C<$tag> combination. 687Returns the BER type mapped to the given C<$class>/C<$tag> combination.
505 688
506=back 689=back
507 690
508=head2 BER TYPES 691=head2 BER Types
509 692
510This lists the predefined BER types - you can map any C<CLASS>/C<TAG> 693This lists the predefined BER types. BER types are formatters used
511combination to any C<BER_TYPE_*>. 694internally to format and encode BER values. You can assign any C<BER_TYPE>
695to any C<CLASS>/C<TAG> combination tgo change how that tag is decoded or
696encoded.
512 697
513=over 698=over
514 699
515=item C<BER_TYPE_BYTES> 700=item C<BER_TYPE_BYTES>
516 701
545dot, e.g. C<1.3.6.1.213>. 730dot, e.g. C<1.3.6.1.213>.
546 731
547=item C<BER_TYPE_RELOID> 732=item C<BER_TYPE_RELOID>
548 733
549Same as C<BER_TYPE_OID> but uses relative object identifier 734Same as C<BER_TYPE_OID> but uses relative object identifier
550encoding: ASN.1 has this hack of encoding the first two OID components 735encoding: ASN.1 uses some hack encoding of the first two OID components
551into a single integer in a weird attempt to save an insignificant amount 736into a single integer in a weird attempt to save an insignificant amount
552of space in an otherwise wasteful encoding, and relative OIDs are 737of space in an otherwise wasteful encoding, and relative OIDs are
553basically OIDs without this hack. The practical difference is that the 738basically OIDs without this hack. The practical difference is that the
554second component of an OID can only have the values 1..40, while relative 739second component of an OID can only have the values 1..40, while relative
555OIDs do not have this restriction. 740OIDs do not have this restriction.
582C<BER_TYPE_BYTES>. When you don't want that but instead prefer a hard 767C<BER_TYPE_BYTES>. When you don't want that but instead prefer a hard
583error for some types, then C<BER_TYPE_CROAK> is for you. 768error for some types, then C<BER_TYPE_CROAK> is for you.
584 769
585=back 770=back
586 771
587=cut 772=head2 Example Profile
588 773
589our $DEFAULT_PROFILE = new Convert::BER::XS::Profile; 774The following creates a profile suitable for SNMP - it's exactly identical
775to the C<$Convert::BER::XS::SNMP_PROFILE> profile.
776
590our $SNMP_PROFILE = new Convert::BER::XS::Profile; 777 our $SNMP_PROFILE = new Convert::BER::XS::Profile;
591 778
592# additional SNMP application types
593$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS); 779 $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS);
594$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT); 780 $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT);
595$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT); 781 $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT);
596$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT); 782 $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT);
597$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_IPADDRESS); 783 $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_BYTES);
598$SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT); 784 $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT);
599
600$DEFAULT_PROFILE->_set_default;
601
6021;
603 785
604=head2 LIMITATIONS/NOTES 786=head2 LIMITATIONS/NOTES
605 787
606This module can only en-/decode 64 bit signed and unsigned integers, and 788This module can only en-/decode 64 bit signed and unsigned
607only when your perl supports those. 789integers/tags/lengths, and only when your perl supports those. So no UUID
790OIDs for now (unless you map the C<OBJECT IDENTIFIER> tag to something
791other than C<BER_TYPE_OID>).
608 792
609This module does not generally care about ranges, i.e. it will happily 793This module does not generally care about ranges, i.e. it will happily
610de-/encode 64 bit integers into an C<ASN_INTEGER> value, or a negative 794de-/encode 64 bit integers into an C<SNMP_UNSIGNED32> value, or a negative
611number into an C<SNMP_COUNTER64>. 795number into an C<SNMP_COUNTER64>.
612 796
613OBJECT IDENTIFIEERs cannot have unlimited length, although the limit is 797OBJECT IDENTIFIEERs cannot have unlimited length, although the limit is
614much larger than e.g. the one imposed by SNMP or other protocols,a nd is 798much larger than e.g. the one imposed by SNMP or other protocols, and is
615about 4kB. 799about 4kB.
616
617Indefinite length encoding is not supported.
618 800
619Constructed strings are decoded just fine, but there should be a way to 801Constructed strings are decoded just fine, but there should be a way to
620join them for convenience. 802join them for convenience.
621 803
622REAL values are not supported and will currently croak. 804REAL values will always be encoded in decimal form and ssometimes is
623 805forced into a perl "NV" type, potentially losing precision.
624This module has undergone little to no testing so far.
625 806
626=head2 ITHREADS SUPPORT 807=head2 ITHREADS SUPPORT
627 808
628This module is unlikely to work when the (officially discouraged) ithreads 809This module is unlikely to work in any other than the loading thread when
629are in use. 810the (officially discouraged) ithreads are in use.
630 811
631=head1 AUTHOR 812=head1 AUTHOR
632 813
633 Marc Lehmann <schmorp@schmorp.de> 814 Marc Lehmann <schmorp@schmorp.de>
634 http://software.schmorp.de/pkg/Convert-BER-XS 815 http://software.schmorp.de/pkg/Convert-BER-XS
635 816
636=cut 817=cut
637 818
8191;
820

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