net-tftp

Trivial File Transfer Protocol (TFTP)

Installation

npm install --save net-tftp

Usage

var TFTP = require( 'net-tftp' )

var server = new TFTP.Server({
  ttl: undefined, // If set, will be used to `socket.setTTL()`
  reuseAddr: false, // Set address reuse for the listening socket
})

server.on( 'read-request', ( transfer ) => {

  // Rejecting a request can be done via `transfer.error()`
  if( transfer.request.filename == 'nope' ) {
    return transfer.error( TFTP.ERROR.NOT_FOUND )
  }

  try {
    var readable = fs.createReadStream( filepath )
    var writable = transfer.accept()
    stream.pipeline( readable, writable, ( error ) => {
      if( error ) transfer.error( TFTP.ERROR.UNDEFINED, 'Internal Server Error' )
    })
  } catch( error ) {
    if( error.code == 'ENOENT' ) {
      transfer.error( TFTP.ERROR.NOT_FOUND )
    } else {
      transfer.error( TFTP.ERROR.UNDEFINED, 'Internal Server Error' )
    }
  }

})

server.on( 'write-request', ( transfer ) => {
  // Accepting a write request returns a readable stream
  var readable = transfer.accept()
  var destination = fs.createWriteStream( transfer.request.filename )

  stream.pipeline( readable, destination, ( error ) => {
    if( error ) transfer.error( TFTP.ERROR.UNDEFINED, 'Internal Server Error' )
  })

})

References

Implemented

• RFC 1350 - THE TFTP PROTOCOL (REVISION 2)

Intent to Implement

• RFC 1782, RFC 2347 - TFTP Option Extension
• RFC 1783, RFC 2348 - TFTP Blocksize Option
• RFC 1784, RFC 2349 - TFTP Timeout Interval and Transfer Size Options

Deviations from RFCs

RFC 1350, Section 2:

TFTP recognizes only one error condition that does not cause termination, the source port of a received packet being incorrect. In this case, an error packet is sent to the originating host.

We do not send error packets to the originating host in this case, to prevent sending interfering traffic, and to protect this from being abused in reflection-based attacks.

Further, any other misdirected packets (such as for example ACKs sent to port 69) receive the same silent treatment, and are simply ignored.

This shouldn't have any detrimental effects as the host sending the misdirected packet should time out eventually on what it believes to be its transaction.

RFC 2347, Negotiation Protocol:

The client appends options at the end of the Read Request or Write request packet, as shown above. Any number of options may be specified; however, an option may only be specified once. The order of the options is not significant.

The restriction that an option may only be specified once is not enforced – instead – the option specified last "wins"