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=head1 NAME |
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Convert::BER::XS - I<very> low level BER decoding |
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=head1 SYNOPSIS |
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use Convert::BER::XS ':all'; |
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my $ber = ber_decode $buf |
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or die "unable to decode SNMP v1/v2c Message"; |
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# the above results in a data structure consisting of (class, tag, |
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# constructed, data) tuples. here is such a message, SNMPv1 trap |
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# with a cisoc mac change notification |
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[ ASN_UNIVERSAL, ASN_SEQUENCE, 1, |
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[ |
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[ ASN_UNIVERSAL, ASN_INTEGER32, 0, 0 ], # snmp version 1 |
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[ ASN_UNIVERSAL, 4, 0, "public" ], # community |
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[ ASN_CONTEXT, 4, 1, # CHOICE, constructed |
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[ |
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[ ASN_UNIVERSAL, ASN_OBJECT_IDENTIFIER, 0, "1.3.6.1.4.1.9.9.215.2" ], # enterprise oid |
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[ ASN_APPLICATION, 0, 0, "\x0a\x00\x00\x01" ], # SNMP IpAddress, 10.0.0.1 |
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[ ASN_UNIVERSAL, ASN_INTEGER32, 0, 6 ], # generic trap |
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[ ASN_UNIVERSAL, ASN_INTEGER32, 0, 1 ], # specific trap |
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[ ASN_APPLICATION, ASN_TIMETICKS, 0, 1817903850 ], # SNMP TimeTicks |
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[ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # the varbindlist |
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[ |
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[ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # a single varbind, "key value" pair |
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[ |
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[ ASN_UNIVERSAL, ASN_OBJECT_IDENTIFIER, 0, "1.3.6.1.4.1.9.9.215.1.1.8.1.2.1" ], # the oid |
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[ ASN_UNIVERSAL, ASN_OCTET_STRING, 0, "...data..." # the value |
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] |
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] |
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], |
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... |
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# let's decode it a bit with some helper functions |
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my $msg = ber_is_seq $ber |
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or die "SNMP message does not start with a sequence"; |
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ber_is $msg->[0], ASN_UNIVERSAL, ASN_INTEGER32, 0 |
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or die "SNMP message does not start with snmp version\n"; |
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# message is SNMP v1 or v2c? |
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if ($msg->[0][BER_DATA] == 0 || $msg->[0][BER_DATA] == 1) { |
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# message is v1 trap? |
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if (ber_is $msg->[2], ASN_CONTEXT, 4, 1) { |
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my $trap = $msg->[2][BER_DATA]; |
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# check whether trap is a cisco mac notification mac changed message |
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if ( |
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(ber_is_oid $trap->[0], "1.3.6.1.4.1.9.9.215.2") # cmnInterfaceObjects |
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and (ber_is_i32 $trap->[2], 6) |
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and (ber_is_i32 $trap->[3], 1) # mac changed msg |
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) { |
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... and so on |
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=head1 DESCRIPTION |
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This module implements a I<very> low level BER/DER decoder, and in the |
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future, probably also an encoder (tell me if you want an encoder, this |
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might speed up the process of getting one). |
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If is tuned for low memory and high speed, while still maintaining some |
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level of user-friendlyness. |
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Currently, not much is documented, as this is an initial release to |
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reserve CPAN namespace, stay tuned for a few days. |
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=head2 RELATIONSHIP TO L<Convert::BER> and L<Convert::ASN1> |
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This module is I<not> the XS version of L<Convert::BER>, but a different |
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take at doing the same thing. I imagine this module would be a good base |
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for speeding up either fo these, or write a similar module, or write your |
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own LDAP or SNMP module for example. |
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=cut |
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package Convert::BER::XS; |
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use common::sense; |
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use XSLoader (); |
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use Exporter qw(import); |
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our $VERSION = '0.0'; |
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XSLoader::load __PACKAGE__, $VERSION; |
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our %EXPORT_TAGS = ( |
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all => [qw( |
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ber_decode |
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ber_is ber_is_seq ber_is_i32 ber_is_oid |
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BER_CLASS BER_TAG BER_CONSTRUCTED BER_DATA |
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ASN_BOOLEAN ASN_INTEGER32 ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER ASN_TAG_BER ASN_TAG_MASK |
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ASN_CONSTRUCTED ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE ASN_CLASS_MASK ASN_CLASS_SHIFT |
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ASN_SEQUENCE ASN_IPADDRESS ASN_COUNTER32 ASN_UNSIGNED32 ASN_TIMETICKS ASN_OPAQUE ASN_COUNTER64 |
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)], |
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); |
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our @EXPORT_OK = map @$_, values %EXPORT_TAGS; |
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1; |
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=head1 AUTHOR |
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Marc Lehmann <schmorp@schmorp.de> |
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http://software.schmorp.de/pkg/Convert-BER-XS |
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=cut |
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