FX-TFTP

Description

FX-TFTP is a slightly over-OO-ed pure-Ruby implementation of plain RFC1350 TFTP server. It is very flexible and intended for hacking. Also, and more importantly, it works, contrary to other gems that are occupying space at RubyGems.

That flexibility may be useful if you're planning on massive custom TFTP-based boots, or if you're into ~~hacking~~ researching cheap router security. The request packets parsing has been relaxed so that it should work with TFTP clients that use some fancy extensions. I have tested the server on Linux x86_64 with Ruby 2.2.0 and on FreeBSD amd64 with Ruby 1.9.3p194, and it successfully exchanged data both ways with clients running on numerous platforms.

The included tftpd executable gives you a fully-fledged read-write TFTP server that also does logging, daemon mode and does not crap out on SIGTERM.

Hacking

Suppose we want to have a TFTP server that only supports reading, but the files served should depend on the IP block the client is connecting from:

class CustomHandler < TFTP::Handler::RWSimple
    ip = src.remote_address.ip_address.split('.')
    block = ip.slice(0, 3).join('-')
    req.filename = File.join(block, req.filename)
    log :info, "#{tag} Mapped filename to #{req.filename}"
    super(tag, req, sock, src)
  end
end

srv = TFTP::Server::Base.new(CustomHandler.new(path, :no_write => true), opts)

When you combine filename inspection and #send and #recv methods working on plain IO objects you can easily whip up things like serving dynamically built scripts/binaries/archives based on parameters passed as the requested 'filename'.

Included executable

$ tftpd
Usage: tftpd [OPTIONS] PORT
    -v, --version                    Show version and exit
    -d, --debug                      Enable debug output
    -l, --log PATH                   Log to file
    -b, --background                 Fork into background
    -m, --mode MODE                  Run in R/W only mode
    -h, --host HOST                  Bind do host
    -p, --path PATH                  Serving root directory
    -o, --overwrite                  Overwrite existing files

Contributing

Fell free to contributed patches using the common GitHub model (descried below). I'm also interested in cases where something doesn't work (weird platforms etc.). If you feel like it please write the client side.

Fork the repo
Checkout a new branch for your changes
Write code and tests, check, commit
Make a Pull Request

Licensing

Standard two-clause BSD license, see LICENSE.txt for details.