DOCSIS::ConfigFile - Decodes and encodes DOCSIS config files

DOCSIS::ConfigFile is a class which provides functionality to decode and encode DOCSIS (Data over Cable Service Interface Specifications) config files.

This module is used as a layer between any human readable data and the binary structure.

The files are usually served using a TFTP server, after a cable modem or MTA (Multimedia Terminal Adapter) has recevied an IP address from a DHCP server. These files are binary encode using a variety of functions, but all the data in the file are constructed by TLVs (type-length-value) blocks. These can be nested and concatenated.

See the source code or https://thorsen.pm/docsisious for list of supported parameters.

use DOCSIS::ConfigFile qw(encode_docsis decode_docsis);

$data = decode_docsis $bytes;
$bytes = encode_docsis({
  GlobalPrivacyEnable => 1,
  MaxCPE              => 2,
  NetworkAccess       => 1,
  BaselinePrivacy     => {
    AuthTimeout       => 10,
    ReAuthTimeout     => 10,
    AuthGraceTime     => 600,
    OperTimeout       => 1,
    ReKeyTimeout      => 1,
    TEKGraceTime      => 600,
    AuthRejectTimeout => 60,
    SAMapWaitTimeout  => 1,
    SAMapMaxRetries   => 4
  },
  SnmpMibObject => [
    {oid => "1.3.6.1.4.1.1.77.1.6.1.1.6.2",    INTEGER => 1},
    {oid => "1.3.6.1.4.1.1429.77.1.6.1.1.6.2", STRING  => "bootfile.bin"}
  ],
  VendorSpecific => {id => "0x0011ee", options => [30 => "0xff", 31 => "0x00", 32 => "0x28"]}
});

You can install the SNMP.pm module to translate between SNMP OID formats. With the module installed, you can define the SnmpMibObject like the example below, instead of using numeric OIDs:

encode_docsis({
  SnmpMibObject => [
    {oid => "docsDevNmAccessIp.1",     IPADDRESS => "10.0.0.1"},
    {oid => "docsDevNmAccessIpMask.1", IPADDRESS => "255.255.255.255"},
  ]
});

There is an example web application bundled with this distribution called "Docsisious". To run this application, you need to install Mojolicious and YAML::XS:

$ curl -L https://cpanmin.us | perl - -M https://cpan.metacpan.org DOCSIS::ConfigFile Mojolicious;

After installing the modules above, you can run the web app like this:

$ docsisious --listen http://*:8000;

And then open your favorite browser at http://localhost:8000. To see a live demo, you can visit https://thorsen.pm/docsisious.

$data = decode_docsis($byte_string);
$data = decode_docsis(\$path_to_file);

Used to decode a DOCSIS config file into a data structure. The output $data can be used as input to "encode_docsis". Note: $data will only contain array-refs if the DOCSIS parameter occur more than once.

$byte_string = encode_docsis(\%data, \%args);

Used to encode a data structure into a DOCSIS config file. Each of the keys in $data can either hold a hash- or array-ref. An array-ref is used if the same DOCSIS parameter occur multiple times. These two formats will result in the same $byte_string:

# Only one SnmpMibObject
encode_docsis({
  SnmpMibObject => {
    oid => "1.3.6.1.4.1.1429.77.1.6.1.1.6.2", STRING => "bootfile.bin"
  }
})

# Allow one or more SnmpMibObjects
encode_docsis({
  SnmpMibObject => [
    {oid => "1.3.6.1.4.1.1429.77.1.6.1.1.6.2", STRING => "bootfile.bin"}
  ]
})

Possible %args:

• mta_algorithm

  This argument is required when encoding MTA config files. Can be set to either empty string, "sha1" or "md5".

• shared_secret

  This argument is optional, but will be used as the shared secret used to increase security between the cable modem and CMTS.

Copyright (C) 2014-2018, Jan Henning Thorsen

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

docsisious bundles Font Awesome.

Jan Henning Thorsen - [email protected]