| … | |
… | |
| 8 | |
8 | |
| 9 | my $ber = ber_decode $buf, $Convert::BER::XS::SNMP_PROFILE |
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, flags, data) |
13 | # (class, tag, flags, 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? |
| … | |
… | |
| 69 | |
69 | |
| 70 | my $buf = ber_encode $ber, $Convert::BER::XS::SNMP_PROFILE; |
70 | my $buf = ber_encode $ber, $Convert::BER::XS::SNMP_PROFILE; |
| 71 | |
71 | |
| 72 | =head1 DESCRIPTION |
72 | =head1 DESCRIPTION |
| 73 | |
73 | |
| 74 | WARNING: Before release 1.0, the API is not considered stable in any way. |
|
|
| 75 | |
|
|
| 76 | This module implements a I<very> low level BER/DER en-/decoder. |
74 | This module implements a I<very> low level BER/DER en-/decoder. |
| 77 | |
75 | |
| 78 | It is tuned for low memory and high speed, while still maintaining some |
76 | It is tuned for low memory and high speed, while still maintaining some |
| 79 | level of user-friendlyness. |
77 | level of user-friendlyness. |
| 80 | |
78 | |
| … | |
… | |
| 108 | BER_CLASS BER_TAG BER_FLAGS BER_DATA |
106 | BER_CLASS BER_TAG BER_FLAGS BER_DATA |
| 109 | |
107 | |
| 110 | =item C<:const_asn> |
108 | =item C<:const_asn> |
| 111 | |
109 | |
| 112 | ASN class values (these are C<0>, C<1>, C<2> and C<3>, respectively - |
110 | ASN class values (these are C<0>, C<1>, C<2> and C<3>, respectively - |
| 113 | exactly thw two topmost bits from the identifier octet shifted 6 bits to |
111 | exactly the two topmost bits from the identifier octet shifted 6 bits to |
| 114 | the right): |
112 | the right): |
| 115 | |
113 | |
| 116 | ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE |
114 | ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE |
| 117 | |
115 | |
| 118 | ASN tag values (some of which are aliases, such as C<ASN_OID>). Their |
116 | ASN tag values (some of which are aliases, such as C<ASN_OID>). Their |
| … | |
… | |
| 296 | Also, since BER is self-delimited, this can be used to decode multiple BER |
294 | Also, since BER is self-delimited, this can be used to decode multiple BER |
| 297 | values joined together. |
295 | values joined together. |
| 298 | |
296 | |
| 299 | =item $bindata = ber_encode $tuple[, $profile] |
297 | =item $bindata = ber_encode $tuple[, $profile] |
| 300 | |
298 | |
| 301 | Encodes the BER tuple into a BER/DER data structure. AS with |
299 | Encodes the BER tuple into a BER/DER data structure. As with |
| 302 | Cyber_decode>, an optional profile can be given. |
300 | Cyber_decode>, an optional profile can be given. |
| 303 | |
301 | |
| 304 | The encoded data should be both BER and DER ("shortest form") compliant |
302 | The encoded data should be both BER and DER ("shortest form") compliant |
| 305 | unless the input says otherwise (e.g. it uses constructed strings). |
303 | unless the input says otherwise (e.g. it uses constructed strings). |
| 306 | |
304 | |
| … | |
… | |
| 409 | use common::sense; |
407 | use common::sense; |
| 410 | |
408 | |
| 411 | use XSLoader (); |
409 | use XSLoader (); |
| 412 | use Exporter qw(import); |
410 | use Exporter qw(import); |
| 413 | |
411 | |
|
|
412 | use Carp (); |
|
|
413 | |
| 414 | our $VERSION; |
414 | our $VERSION; |
| 415 | |
415 | |
| 416 | BEGIN { |
416 | BEGIN { |
| 417 | $VERSION = '1.0'; |
417 | $VERSION = 1.21; |
| 418 | XSLoader::load __PACKAGE__, $VERSION; |
418 | XSLoader::load __PACKAGE__, $VERSION; |
| 419 | } |
419 | } |
| 420 | |
420 | |
| 421 | our %EXPORT_TAGS = ( |
421 | our %EXPORT_TAGS = ( |
| 422 | const_index => [qw( |
422 | const_index => [qw( |
| … | |
… | |
| 468 | |
468 | |
| 469 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS); |
469 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS); |
| 470 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT); |
470 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT); |
| 471 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT); |
471 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT); |
| 472 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT); |
472 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT); |
| 473 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_IPADDRESS); |
473 | |
|
|
474 | # decodes REAL values according to ECMA-63 |
|
|
475 | # this is pretty strict, except it doesn't catch -0. |
|
|
476 | # I don't have access to ISO 6093 (or BS 6727, or ANSI X.3-42)), so this is all guesswork. |
|
|
477 | sub _decode_real_decimal { |
|
|
478 | my ($format, $val) = @_; |
|
|
479 | |
|
|
480 | $val =~ y/,/./; # probably not in ISO-6093 |
|
|
481 | |
|
|
482 | if ($format == 1) { |
|
|
483 | $val =~ /^ \ * [+-]? [0-9]+ \z/x |
|
|
484 | or Carp::croak "BER_TYPE_REAL NR1 value not in NR1 format ($val) (X.690 8.5.8)"; |
|
|
485 | } elsif ($format == 2) { |
|
|
486 | $val =~ /^ \ * [+-]? (?: [0-9]+\.[0-9]* | [0-9]*\.[0-9]+ ) \z/x |
|
|
487 | or Carp::croak "BER_TYPE_REAL NR2 value not in NR2 format ($val) (X.690 8.5.8)"; |
|
|
488 | } elsif ($format == 3) { |
|
|
489 | $val =~ /^ \ * [+-] (?: [0-9]+\.[0-9]* | [0-9]*\.[0-9]+ ) [eE] [+-]? [0-9]+ \z/x |
|
|
490 | or Carp::croak "BER_TYPE_REAL NR3 value not in NR3 format ($val) (X.690 8.5.8)"; |
|
|
491 | } else { |
|
|
492 | Carp::croak "BER_TYPE_REAL invalid decimal numerical representation format $format"; |
|
|
493 | } |
|
|
494 | |
|
|
495 | $val |
|
|
496 | } |
|
|
497 | |
|
|
498 | # this is a mess, but perl's support for floating point formatting is nearly nonexistant |
|
|
499 | sub _encode_real_decimal { |
|
|
500 | my ($val, $nvdig) = @_; |
|
|
501 | |
|
|
502 | $val = sprintf "%.*G", $nvdig + 1, $val; |
|
|
503 | |
|
|
504 | if ($val =~ /E/) { |
|
|
505 | $val =~ s/E(?=[^+-])/E+/; |
|
|
506 | $val =~ s/E/.E/ if $val !~ /\./; |
|
|
507 | $val =~ s/^/+/ unless $val =~ /^-/; |
|
|
508 | |
|
|
509 | return "\x03$val" # NR3 |
|
|
510 | } |
|
|
511 | |
|
|
512 | $val =~ /\./ |
|
|
513 | ? "\x02$val" # NR2 |
|
|
514 | : "\x01$val" # NR1 |
|
|
515 | } |
| 474 | |
516 | |
| 475 | =head2 DEBUGGING |
517 | =head2 DEBUGGING |
| 476 | |
518 | |
| 477 | To aid debugging, you cna call the C<ber_dump> function to print a "nice" |
519 | To aid debugging, you can call the C<ber_dump> function to print a "nice" |
| 478 | representation to STDOUT. |
520 | representation to STDOUT. |
| 479 | |
521 | |
| 480 | =over |
522 | =over |
| 481 | |
523 | |
| 482 | =item ber_dump $tuple[, $profile[, $prefix]] |
524 | =item ber_dump $tuple[, $profile[, $prefix]] |
| 483 | |
525 | |
| 484 | In addition to specifying the BER C<$tuple> to dump, youc an also specify |
526 | In addition to specifying the BER C<$tuple> to dump, you can also specify |
| 485 | a C<$profile> and a C<$prefix> string that is printed in front of each line. |
527 | a C<$profile> and a C<$prefix> string that is printed in front of each line. |
| 486 | |
528 | |
| 487 | If C<$profile> is C<$Convert::BER::XS::SNMP_PROFILE>, then C<ber_dump> |
529 | If C<$profile> is C<$Convert::BER::XS::SNMP_PROFILE>, then C<ber_dump> |
| 488 | will try to improve its output for SNMP data. |
530 | will try to improve its output for SNMP data. |
| 489 | |
531 | |
| … | |
… | |
| 496 | Example output: |
538 | Example output: |
| 497 | |
539 | |
| 498 | SEQUENCE |
540 | SEQUENCE |
| 499 | | OCTET_STRING bytes 800063784300454045045400000001 |
541 | | OCTET_STRING bytes 800063784300454045045400000001 |
| 500 | | OCTET_STRING bytes |
542 | | OCTET_STRING bytes |
| 501 | | CONTEXT (7) bytes CONSTRUCTED |
543 | | CONTEXT (7) CONSTRUCTED |
| 502 | | | INTEGER int 1058588941 |
544 | | | INTEGER int 1058588941 |
| 503 | | | INTEGER int 0 |
545 | | | INTEGER int 0 |
| 504 | | | INTEGER int 0 |
546 | | | INTEGER int 0 |
| 505 | | | SEQUENCE |
547 | | | SEQUENCE |
| 506 | | | | SEQUENCE |
548 | | | | SEQUENCE |
| 507 | | | | | OID oid 1.3.6.1.2.1.1.3.0 |
549 | | | | | OID oid 1.3.6.1.2.1.1.3.0 |
| 508 | | | | | TIMETICKS int 638085796 |
550 | | | | | TIMETICKS int 638085796 |
| 509 | |
551 | |
|
|
552 | =back |
|
|
553 | |
| 510 | =cut |
554 | =cut |
| 511 | |
555 | |
| 512 | # reverse enum, very slow and ugly hack |
556 | # reverse enum, very slow and ugly hack |
| 513 | sub _re { |
557 | sub _re { |
| 514 | my ($export_tag, $value) = @_; |
558 | my ($export_tag, $value) = @_; |
| … | |
… | |
| 547 | $class =~ s/^ASN_//; |
591 | $class =~ s/^ASN_//; |
| 548 | $tag =~ s/^(ASN_|SNMP_)//; |
592 | $tag =~ s/^(ASN_|SNMP_)//; |
| 549 | $type =~ s/^BER_TYPE_//; |
593 | $type =~ s/^BER_TYPE_//; |
| 550 | |
594 | |
| 551 | if ($ber->[BER_FLAGS]) { |
595 | if ($ber->[BER_FLAGS]) { |
| 552 | printf "$indent%-16.16s %-6.6s CONSTRUCTED\n", $tag, lc $type; |
596 | printf "$indent%-16.16s\n", $tag; |
| 553 | &_ber_dump ($_, $profile, "$indent| ") |
597 | &_ber_dump ($_, $profile, "$indent| ") |
| 554 | for @$data; |
598 | for @$data; |
| 555 | } else { |
599 | } else { |
| 556 | if ($data =~ y/\x20-\x7e//c / (length $data || 1) > 0.2 or $data =~ /\x00./s) { |
600 | if ($data =~ y/\x20-\x7e//c / (length $data || 1) > 0.2 or $data =~ /\x00./s) { |
| 557 | # assume binary |
601 | # assume binary |
| 558 | $data = unpack "H*", $data; |
602 | $data = unpack "H*", $data; |
| 559 | substr $data, 40, 1e9, "..." if 40 < length $data; |
|
|
| 560 | } else { |
603 | } else { |
| 561 | $data =~ s/[^\x20-\x7e]/./g; |
604 | $data =~ s/[^\x20-\x7e]/./g; |
| 562 | $data = "\"$data\"" if $type =~ /string/i; |
605 | $data = "\"$data\"" if $tag =~ /string/i || !length $data; |
| 563 | substr $data, 40, 1e9, "..." if 40 < length $data; |
|
|
| 564 | } |
606 | } |
|
|
607 | |
|
|
608 | substr $data, 40, 1e9, "..." if 40 < length $data; |
| 565 | |
609 | |
| 566 | printf "$indent%-16.16s %-6.6s %s\n", $tag, lc $type, $data; |
610 | printf "$indent%-16.16s %-6.6s %s\n", $tag, lc $type, $data; |
| 567 | } |
611 | } |
| 568 | } |
612 | } |
| 569 | } |
613 | } |
| … | |
… | |
| 639 | |
683 | |
| 640 | Returns the BER type mapped to the given C<$class>/C<$tag> combination. |
684 | Returns the BER type mapped to the given C<$class>/C<$tag> combination. |
| 641 | |
685 | |
| 642 | =back |
686 | =back |
| 643 | |
687 | |
| 644 | =head2 BER TYPES |
688 | =head2 BER Types |
| 645 | |
689 | |
| 646 | This lists the predefined BER types - you can map any C<CLASS>/C<TAG> |
690 | This lists the predefined BER types. BER types are formatters used |
| 647 | combination to any C<BER_TYPE_*>. |
691 | internally to format and encode BER values. You can assign any C<BER_TYPE> |
|
|
692 | to any C<CLASS>/C<TAG> combination tgo change how that tag is decoded or |
|
|
693 | encoded. |
| 648 | |
694 | |
| 649 | =over |
695 | =over |
| 650 | |
696 | |
| 651 | =item C<BER_TYPE_BYTES> |
697 | =item C<BER_TYPE_BYTES> |
| 652 | |
698 | |
| … | |
… | |
| 681 | dot, e.g. C<1.3.6.1.213>. |
727 | dot, e.g. C<1.3.6.1.213>. |
| 682 | |
728 | |
| 683 | =item C<BER_TYPE_RELOID> |
729 | =item C<BER_TYPE_RELOID> |
| 684 | |
730 | |
| 685 | Same as C<BER_TYPE_OID> but uses relative object identifier |
731 | Same as C<BER_TYPE_OID> but uses relative object identifier |
| 686 | encoding: ASN.1 has this hack of encoding the first two OID components |
732 | encoding: ASN.1 uses some hack encoding of the first two OID components |
| 687 | into a single integer in a weird attempt to save an insignificant amount |
733 | into a single integer in a weird attempt to save an insignificant amount |
| 688 | of space in an otherwise wasteful encoding, and relative OIDs are |
734 | of space in an otherwise wasteful encoding, and relative OIDs are |
| 689 | basically OIDs without this hack. The practical difference is that the |
735 | basically OIDs without this hack. The practical difference is that the |
| 690 | second component of an OID can only have the values 1..40, while relative |
736 | second component of an OID can only have the values 1..40, while relative |
| 691 | OIDs do not have this restriction. |
737 | OIDs do not have this restriction. |
| … | |
… | |
| 729 | |
775 | |
| 730 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS); |
776 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS); |
| 731 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT); |
777 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT); |
| 732 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT); |
778 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT); |
| 733 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT); |
779 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT); |
| 734 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_IPADDRESS); |
780 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_BYTES); |
| 735 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT); |
781 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER64 , BER_TYPE_INT); |
| 736 | |
782 | |
| 737 | =head2 LIMITATIONS/NOTES |
783 | =head2 LIMITATIONS/NOTES |
| 738 | |
784 | |
| 739 | This module can only en-/decode 64 bit signed and unsigned integers, and |
785 | This module can only en-/decode 64 bit signed and unsigned |
| 740 | only when your perl supports those. |
786 | integers/tags/lengths, and only when your perl supports those. So no UUID |
|
|
787 | OIDs for now (unless you map the C<OBJECT IDENTIFIER> tag to something |
|
|
788 | other than C<BER_TYPE_OID>). |
| 741 | |
789 | |
| 742 | This module does not generally care about ranges, i.e. it will happily |
790 | This module does not generally care about ranges, i.e. it will happily |
| 743 | de-/encode 64 bit integers into an C<ASN_INTEGER> value, or a negative |
791 | de-/encode 64 bit integers into an C<SNMP_UNSIGNED32> value, or a negative |
| 744 | number into an C<SNMP_COUNTER64>. |
792 | number into an C<SNMP_COUNTER64>. |
| 745 | |
793 | |
| 746 | OBJECT IDENTIFIEERs cannot have unlimited length, although the limit is |
794 | OBJECT IDENTIFIEERs cannot have unlimited length, although the limit is |
| 747 | much larger than e.g. the one imposed by SNMP or other protocols,a nd is |
795 | much larger than e.g. the one imposed by SNMP or other protocols, and is |
| 748 | about 4kB. |
796 | about 4kB. |
| 749 | |
|
|
| 750 | Indefinite length encoding is not supported. |
|
|
| 751 | |
797 | |
| 752 | Constructed strings are decoded just fine, but there should be a way to |
798 | Constructed strings are decoded just fine, but there should be a way to |
| 753 | join them for convenience. |
799 | join them for convenience. |
| 754 | |
800 | |
| 755 | REAL values are not supported and will currently croak. |
801 | REAL values will always be encoded in decimal form and ssometimes is |
| 756 | |
802 | forced into a perl "NV" type, potentially losing precision. |
| 757 | The encoder and decoder tend to accept more formats than should be |
|
|
| 758 | strictly supported. |
|
|
| 759 | |
|
|
| 760 | This module has undergone little to no testing so far. |
|
|
| 761 | |
803 | |
| 762 | =head2 ITHREADS SUPPORT |
804 | =head2 ITHREADS SUPPORT |
| 763 | |
805 | |
| 764 | This module is unlikely to work when the (officially discouraged) ithreads |
806 | This module is unlikely to work in any other than the loading thread when |
| 765 | are in use. |
807 | the (officially discouraged) ithreads are in use. |
| 766 | |
808 | |
| 767 | =head1 AUTHOR |
809 | =head1 AUTHOR |
| 768 | |
810 | |
| 769 | Marc Lehmann <schmorp@schmorp.de> |
811 | Marc Lehmann <schmorp@schmorp.de> |
| 770 | http://software.schmorp.de/pkg/Convert-BER-XS |
812 | http://software.schmorp.de/pkg/Convert-BER-XS |
