| Convert::ASN1 - ASN.1 Encode/Decode library |
Convert::ASN1 - ASN.1 Encode/Decode library
version 0.27
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)
Convert::ASN1 encodes and decodes ASN.1 data structures using BER/DER rules.
Contructor, creates a new object.
If given, OPTIONS are the same ones as for configure ( OPTIONS ) below.
Returns the last error.
Configure options to control how Convert::ASN1 will perform various tasks. Options are passed as name-value pairs.
Encode options
withzone.
timezone
configure option.
Decode options
utctime.
time function.
utctime, the second is the timezone offset, in seconds, that was
used in the encoding.
1.
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.
Compile the ASN.1 description to be read from the specified pathname.
Find a macro from a prepared ASN.1 description. Returns an object which can be used for encode/decode.
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 the PDU, returns a reference to a hash containg the values for the PDU. Returns undef if there was an error.
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 ).
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 ).
As well as providing an object interface for encoding/decoding PDUs Convert::ASN1 also provides the following functions.
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.
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.
send, see the perlfunc manpage
syswrite with 2 arguments, see the perlfunc manpage
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 works with asn_get. It will return true if asn_get has already
read enough data into the buffer to return a complete element.
TAG.
LEN.
LEN to its ASN.1 encoding.
STDERR if the handle is not given.
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.
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 {...}.
Graham Barr <gbarr@cpan.org>
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 (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.
| Convert::ASN1 - ASN.1 Encode/Decode library |