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package main
import (
"flag"
"fmt"
"io"
"net/http"
"os"
"path"
"path/filepath"
"time"
"github.com/pin/tftp"
)
var url string
var dir string
// readHandler is called when client starts file download from server
func readHandler(filename string, rf io.ReaderFrom) error {
file_path := path.Join(dir, filepath.Clean(path.Join("/", filename)))
if _, err := os.Stat(file_path); err == nil {
file, err := os.Open(file_path)
if err != nil {
fmt.Fprintf(os.Stderr, "%v\n", err)
return err
}
fi, err := file.Stat()
if err != nil {
fmt.Fprintf(os.Stderr, "%v\n", err)
return err
}
rf.(tftp.OutgoingTransfer).SetSize(fi.Size())
n, err := rf.ReadFrom(file)
if err != nil {
fmt.Fprintf(os.Stderr, "%v\n", err)
return err
}
fmt.Printf("%s %d bytes sent\n", filename, n)
} else { // File not found locally. Proxying the request.
fileUrl := url + "/" + filename
resp, err := http.Get(fileUrl)
if err != nil {
fmt.Fprintf(os.Stderr, "%v\n", err)
return err
}
defer resp.Body.Close()
if resp.StatusCode != 200 {
io.Copy(io.Discard, resp.Body)
return fmt.Errorf("received status code: %d", resp.StatusCode)
}
rf.(tftp.OutgoingTransfer).SetSize(resp.ContentLength)
n, err := rf.ReadFrom(resp.Body)
if err != nil {
fmt.Fprintf(os.Stderr, "%v\n", err)
return err
}
fmt.Printf("%s %d bytes sent\n", filename, n)
}
return nil
}
func main() {
flag.StringVar(&dir, "dir", "/var/lib/tftpboot", "The directory to serve files from. For example /var/lib/tftpboot")
flag.StringVar(&url, "url", "http://example.com", "The URL to proxy requests to. For example http://example.com")
flag.Parse()
// use nil in place of handler to disable read or write operations
s := tftp.NewServer(readHandler, nil)
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)
}
}
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