This package provides a JavaScript implementation of the open Community ID flow tuple hashing standard.

It targets Node 18 and newer and has no additional dependencies.

This package is available via NPM, therefore:

$ npm install -g communityid

To install locally from a git clone, you can also use npm, e.g. by saying

$ npm install /path/to/the/clone

The package works with local or global installation. It ships with an executable to provide command-line Community ID calculation (see below), for which global installation is recommended.

The API is very simple:

const communityid = require('communityid');

console.log(communityid.calc('tcp', '127.0.0.1', '10.0.0.1', 1234, 80));

This will print "1:mgRgpIZSu0KHDp/QrtcWZpkJpMU=". For details on the arguments and their types, please see the calc function's docstring. Seeding is supported, and base64 encoding can optionally be disabled. In case of problems with the input arguments, the function returns null and reports an error message through the package's communityid.error() function, which defaults to console.error().

The package includes a sample application, community-id, which calculates the ID for given flow tuples. See its --help output for details. An example:

$ community-id tcp 10.0.0.1 10.0.0.2 10 20
1:9j2Dzwrw7T9E+IZi4b4IVT66HBI=

For troubleshooting, the communityid.calc() implementation can report the hashed data to stderr. To enable, set (or add) the communityid debug stream in your NODE_DEBUG environment variable:

$ NODE_DEBUG=communityid community-id tcp 10.0.0.1 10.0.0.2 10 20
COMMUNITYID 1182249:    seed 00:00
COMMUNITYID 1182249:   saddr 0a:00:00:01
COMMUNITYID 1182249:   daddr 0a:00:00:02
COMMUNITYID 1182249:   proto 06
COMMUNITYID 1182249: padding 00
COMMUNITYID 1182249:   sport 00:0a
COMMUNITYID 1182249:   dport 00:14
1:9j2Dzwrw7T9E+IZi4b4IVT66HBI=

The package includes a testsuite in the test folder, via Node's test runner. To execute, run the following from the toplevel or the test folder:

$ node --test
✔ icmp 1 (3.838516ms)
✔ icmp 2 (0.338138ms)
✔ icmp 3 (0.446812ms)
...

The package currently does not support browser-side operation. Contributions very welcome!