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

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

VERSION
       version 0.27

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 ( [OPTIONS] )
       Contructor, creates a new object.

       If given, OPTIONS are the same ones as for "configure ( OPTIONS )"
       below.

   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'

       tagdefault
	   One of 'EXPLICIT' or	'IMPLICIT'.  Default tagging conventions are
	   normally given in the ASN.1 module definition (not supported	by the
	   parser). The	ASN.1 spec states EXPLICIT tagging is the default, but
	   this	option has IMPLICIT tagging default for	backward compatibility
	   reasons.

       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 overridden 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.

       null
	   The value to	decode ASN.1 NULL types	into.  If not set, it defaults
	   to 1.

   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.

   registeroid ( OID, HANDLER )
       Register	a handler for all ASN.1	elements that are "DEFINED BY" the
       given OID.

       HANDLER must be a Convert::ASN1 object, e.g. as returned	by "find (
       MACRO )".

   registertype	( NAME,	OID, HANDLER )
       Register	a handler for all ASN.1	elements named "NAME", that are
       "DEFINED	BY" the	given OID.

       HANDLER must be a Convert::ASN1 object, e.g. as returned	by "find (
       MACRO )".

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 ( CLASS,	VALUE )
	   Given CLASS and a VALUE, calculate an integer which when encoded
	   will	become the tag.

       asn_decode_tag (	TAG )
	   Decode the given ASN.1 encoded "TAG".

       asn_encode_tag (	TAG )
	   Encode TAG value for	encoding.  We assume that the tag has been
	   correctly generated with "asn_tag ( CLASS, VALUE )".

       asn_decode_length ( LEN )
	   Decode the given ASN.1 decoded "LEN".

       asn_encode_length ( LEN )
	   Encode the given "LEN" to its ASN.1 encoding.

   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	( [FH,]	BUFFER )
	   Try to decode the given buffer as ASN.1 structure and dump it to
	   the given file handle, or "STDERR" if the handle is not given.

       asn_hexdump ( FH, BUFFER	)

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_hexdump

       :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	},
	 ]}

       Finally,	if you wish to pre-parse ASN.1 and hold	it to include inline
       in your PDU, you	can coerce it into the ASN.1 spec by defining the
       value as	ANY in the schema, and then pass the pre encoded value inline.

	 # ASN.1
	 int INTEGER,
	 str OCTET STRING,
	 pre ANY

	 # Perl
	 { int => 5, str => "text", pre=>"\x03\x03\x00\x0a\x05"	}

       passes a	pre-encoded BIT	STRING instance	as hex text. -But it could be
       a previous run of $obj->encode()	from another run held in some
       variable.

   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 <gbarr@cpan.org>

SUPPORT
       Report issues via github	at
       https://github.com/gbarr/perl-Convert-ASN1/issues

       To contribute I encourage you to	create a git fork of the repository at
       https://github.com/gbarr/perl-Convert-ASN1 do you work on a fresh
       branch created from master and submit a pull request

COPYRIGHT
       Copyright (c) 2000-2012 Graham Barr <gbarr@cpan.org>. All rights
       reserved.  This program is free software; you can redistribute it
       and/or modify it	under the same terms as	Perl itself.

perl v5.32.0			  2014-06-25		      Convert::ASN1(3)

NAME | VERSION | SYNOPSYS | DESCRIPTION | METHODS | EXPORTS | EXPORT TAGS | MAPPING ASN.1 TO PERL | TODO | AUTHOR | SUPPORT | COPYRIGHT

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