TFTP server and client library for Golang

Implements:

• RFC 1350 - The TFTP Protocol (Revision 2)
• RFC 2347 - TFTP Option Extension
• RFC 2348 - TFTP Blocksize Option

Partially implements (tsize server side only):

• RFC 2349 - TFTP Timeout Interval and Transfer Size Options

Set of features is sufficient for PXE boot support.

import "github.com/pin/tftp"

TFTP Server

func writeHanlder(filename string, w io.WriterTo) error {
	file, err := os.OpenFile(filename, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0644)
	if err != nil {
		fmt.Fprintf(os.Stderr, "%v\n", err)
		return err
	}
	// In case client provides tsize option.
	if t, ok := wt.(tftp.IncomingTransfer); ok {
		if n, ok := t.Size(); ok {
			fmt.Printf("Transfer size: %d\n", n)
		}
	}
	n, err := w.WriteTo(file)
	if err != nil {
		fmt.Fprintf(os.Stderr, "%v\n", err)
		return err
	}
	fmt.Printf("%d bytes received\n", n)
	return nil
}

func readHandler(filename string, r io.ReaderFrom) error {
	file, err := os.Open(filename)
	if err != nil {
		fmt.Fprintf(os.Stderr, "%v\n", err)
		return err
	}
	// Optional tsize support.
	// Set transfer size before calling ReadFrom.
	if t, ok := rf.(tftp.OutgoingTransfer); ok {
		if fi, err := file.Stat(); err == nil {
			t.SetSize(fi.Size())
		}
	}
	n, err := r.ReadFrom(file)
	if err != nil {
		fmt.Fprintf(os.Stderr, "%v\n", err)
		return err
	}
	fmt.Printf("%d bytes sent\n", n)
	return nil
}

func main() {
	// use nil in place of handler to disable read or write operations
	s := tftp.NewServer(readHandler, writeHanlder)
	s.SetTimeout(5 * time.Second) // optional
	err := s.ListenAndServe(":69") // blocks until s.Shutdown() is called
	if err != nil {
		fmt.Fprintf(os.Stdout, "server: %v\n", err)
		os.Exit(1)
	}
}

TFTP Client

Uploading file to server:

// TODO: handle errors
c, err := tftp.NewClient("172.16.4.21:69")
file, err := os.Open(path)
c.SetTimeout(5 * time.Second) // optional
r, err := c.Send("foobar.txt", "octet")
n, err := r.ReadFrom(file)
fmt.Printf("%d bytes sent\n", n)

Downloading file from server:

// TODO: handle errors
c, err := tftp.NewClient("172.16.4.21:69")
w, err := c.Receive("foobar.txt", "octet")
file, err := os.Create(path)
// Optional tsize.
if it, ok := readTransfer.(IncomingTransfer); ok {
	if n, ok := it.Size(); ok {
		fmt.Printf("Transfer size: %d\n", n)
	}
}
n, err := w.WriteTo(file)
fmt.Printf("%d bytes received\n", n)

Legacy API

API has been improved in non-backward-compartible way recently. Please use v1 release in legacy code.

Legacy code should import http://gopkg.in/pin/tftp.v1