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Convert::ASN1(3pm)    User Contributed Perl Documentation   Convert::ASN1(3pm)



NAME
       Convert::ASN1 - ASN.1 Encode/Decode library

SYNOPSYS
         use Convert::ASN1;

         $asn = Convert::ASN1->new;
         $asn->prepare(q<

           [APPLICATION 7] SEQUENCE {
             int INTEGER,
             str OCTET STRING
           }

         >);

         $pdu = $asn->encode( int => 7, str => "string");

         $out = $asn->decode($pdu);
         print $out->{int}," ",$out->{str},"\n";

         use Convert::ASN1 qw(:io);

         $peer   = asn_recv($sock,$buffer,0);
         $nbytes = asn_read($fh, $buffer);
         $nbytes = asn_send($sock, $buffer, $peer);
         $nbytes = asn_send($sock, $buffer);
         $nbytes = asn_write($fh, $buffer);
         $buffer = asn_get($fh);
         $yes    = asn_ready($fh)

DESCRIPTION
       Convert::ASN1 encodes and decodes ASN.1 data structures using BER/DER
       rules.

METHODS
       new

       Contructor, creates a new object.

       error

       Returns the last error.

       configure ( OPTIONS )

       Configure options to control how Convert::ASN1 will perform various
       tasks.  Options are passed as name-value pairs.

       encode
           Reference to a hash which contains various encode options.

       decode
           Reference to a hash which contains various decode options.

       encoding
           One of 'BER' or 'DER'. The default is 'BER'

       Encode options

       real
           Which encoding to use for real's. One of 'binary', 'nr1', 'nr2',
           'nr3'

       time
           This controls how UTCTime and GeneralizedTime elements are encoded.
           The default is "withzone".

           utctime
               The value passed will be encoded without a zone, ie a UTC
               value.

           withzone
               The value will be encoded with a zone. By default it will be
               encoded using the local time offset. The offset may be set
               using the "timezone" configure option.

           raw The value passed should already be in the correct format and
               will be copied into the PDU as-is.

       timezone
           By default UTCTime and GeneralizedTime will be encoded using the
           local time offset from UTC. This will over-ride that. It is an
           offset from UTC in seconds.  This option can be overriden by
           passing a reference to a list of two values as the time value. The
           list should contain the time value and the offset from UTC in
           seconds.

       bigint
           If during encoding an value greater than 32 bits is discovered and
           is not already a big integer object, then the value will first be
           converted into a big integer object. This option controls the big
           integer class into which the objects will be blessed. The default
           is to use Math::BigInt

       Decode options

       time
           This controls how a UTCTime or a GeneralizedTime element will be
           decoded. The default is "utctime".

           utctime
               The value returned will be a time value as returned by the
               "time" function.

           withzone
               The value returned will be a reference to an array of two
               values. The first is the same as with "utctime", the second is
               the timezone offset, in seconds, that was used in the encoding.

           raw The value returned will be the raw encoding as extracted from
               the PDU.

       bigint
           If during decoding any big integers are discovered (integers
           greater than 32 bits), they will be decoded into big integer
           objects. This option controls the big integer class into which the
           objects will be blessed.  The default is to use Math::BigInt.

       prepare ( ASN )

       Compile the given ASN.1 descripton which can be passed as a string or
       as a filehandle. The syntax used is very close to ASN.1, but has a few
       differences. If the ASN decribes only one macro then encode/decode can
       be called on this object. If ASN describes more than one ASN.1 macro
       then "find" must be called. The method returns undef on error.

       prepare_file ( ASNPATH )

       Compile the ASN.1 description to be read from the specified pathname.

       find ( MACRO )

       Find a macro from a prepared ASN.1 description. Returns an object which
       can be used for encode/decode.

       encode ( VARIABLES )

       Encode a PDU. Top-level variable are passed as name-value pairs, or as
       a reference to a hash containing them. Returns the encoded PDU, or
       undef on error.

       decode ( PDU )

       Decode the PDU, returns a reference to a hash containg the values for
       the PDU. Returns undef if there was an error.

EXPORTS
       As well as providing an object interface for encoding/decoding PDUs
       Convert::ASN1 also provides the following functions.

       IO Functions

       asn_recv SOCK, BUFFER, FLAGS
           Will read a single element from the socket SOCK into BUFFER.  FLAGS
           may be MSG_PEEK as exported by "Socket". Returns the address of the
           sender, or undef if there was an error. Some systems do not support
           the return of the peer address when the socket is a connected
           socket, in these cases the empty string will be returned. This is
           the same behaviour as the "recv" function in perl itself.

           It is recommended that if the socket is of type SOCK_DGRAM then
           "recv" be called directly instead of calling "asn_recv".

       asn_read FH, BUFFER, OFFSET
       asn_read FH, BUFFER
           Will read a single element from the filehandle FH into BUFFER.
           Returns the number of bytes read if a complete element was read, -1
           if an incomplete element was read or undef if there was an error.
           If OFFSET is specified then it is assumed that BUFFER already
           contains an incomplete element and new data will be appended
           starting at OFFSET.

           If FH is a socket the asn_recv is used to read the element, so the
           same restiction applies if FH is a socket of type SOCK_DGRAM.

       asn_send SOCK, BUFFER, FLAGS, TO
       asn_send SOCK, BUFFER, FLAGS
           Identical to calling "send", see perlfunc

       asn_write FH, BUFFER
           Identical to calling "syswrite" with 2 arguments, see perlfunc

       asn_get FH
           "asn_get" provides buffered IO. Because it needs a buffer FH must
           be a GLOB or a reference to a GLOB. "asn_get" will use two entries
           in the hash element of the GLOB to use as its buffer:

             asn_buffer - input buffer
             asn_need   - number of bytes needed for the next element, if known

           Returns an element or undef if there was an error.

       asn_ready FH
           "asn_ready" works with "asn_get". It will return true if "asn_get"
           has already read enough data into the buffer to return a complete
           element.

       Encode/Decode Functions

       asn_tag
       asn_decode_tag
       asn_encode_tag
       asn_decode_length
       asn_encode_length

       Constants

       ASN_BIT_STR
       ASN_BOOLEAN
       ASN_ENUMERATED
       ASN_GENERAL_TIME
       ASN_IA5_STR
       ASN_INTEGER
       ASN_NULL
       ASN_OBJECT_ID
       ASN_OCTET_STR
       ASN_PRINT_STR
       ASN_REAL
       ASN_SEQUENCE
       ASN_SET
       ASN_UTC_TIME
       ASN_APPLICATION
       ASN_CONTEXT
       ASN_PRIVATE
       ASN_UNIVERSAL
       ASN_PRIMITIVE
       ASN_CONSTRUCTOR
       ASN_LONG_LEN
       ASN_EXTENSION_ID
       ASN_BIT

       Debug Functions

       asn_dump
       asn_hexdump

EXPORT TAGS
       :all
           All exported functions

       :const
           ASN_BOOLEAN,     ASN_INTEGER,      ASN_BIT_STR,      ASN_OCTET_STR,
           ASN_NULL,        ASN_OBJECT_ID,    ASN_REAL,
           ASN_ENUMERATED, ASN_SEQUENCE,    ASN_SET,          ASN_PRINT_STR,
           ASN_IA5_STR, ASN_UTC_TIME,    ASN_GENERAL_TIME, ASN_UNIVERSAL,
           ASN_APPLICATION,  ASN_CONTEXT,      ASN_PRIVATE, ASN_PRIMITIVE,
           ASN_CONSTRUCTOR,  ASN_LONG_LEN,     ASN_EXTENSION_ID, ASN_BIT

       :debug
           asn_dump, asn_dumphex

       :io asn_recv, asn_send, asn_read, asn_write, asn_get, asn_ready

       :tag
           asn_tag, asn_decode_tag, asn_encode_tag, asn_decode_length,
           asn_encode_length

MAPPING ASN.1 TO PERL
       Every element in the ASN.1 definition has a name, in perl a hash is
       used with these names as an index and the element value as the hash
       value.

         # ASN.1
         int INTEGER,
         str OCTET STRING

         # Perl
         { int => 5, str => "text" }

       In the case of a SEQUENCE, SET or CHOICE then the value in the
       namespace will be a hash reference which will be the namespce for the
       elements with that element.

         # ASN.1
         int INTEGER,
         seq SEQUENCE {
           str OCTET STRING,
           bool BOOLEAN
         }

         # Perl
         { int => 5, seq => { str => "text", bool => 1}}

       If the element is a SEQUENCE OF, or SET OF, then the value in the
       namespace will be an array reference. The elements in the array will be
       of the type expected by the type following the OF. For example with
       "SEQUENCE OF STRING" the array would contain strings. With "SEQUENCE OF
       SEQUENCE { ... }" the array will contain hash references which will be
       used as namespaces

         # ASN.1
         int INTEGER,
         str SEQUENCE OF OCTET STRING

         # Perl
         { int => 5, str => [ "text1", "text2"]}

         # ASN.1
         int INTEGER,
         str SEQUENCE OF SEQUENCE {
           type OCTET STRING,
           value INTEGER
         }

         # Perl
         { int => 5, str => [
           { type => "abc", value => 4 },
           { type => "def", value => -1 },
         ]}

       Exceptions

       There are some exceptions where Convert::ASN1 does not require an
       element to be named.  These are SEQUENCE {...}, SET {...} and CHOICE.
       In each case if the element is not given a name then the elements
       inside the {...} will share the same namespace as the elements outside
       of the {...}.

TODO
       o   XS implementation.

       o   More documentation.

       o   More tests.

AUTHOR
       Graham Barr <gbarrATpobox.com>, Report bugs via
       <bug-Convert-ASN1ATrt.org>

COPYRIGHT
       Copyright (c) 2000-2005 Graham Barr <gbarrATpobox.com>. All rights
       reserved.  This program is free software; you can redistribute it
       and/or modify it under the same terms as Perl itself.



perl v5.10.0                      2007-02-03                Convert::ASN1(3pm)