ensc/r-tftpd

TFTP server with RFC 7440 "windowsize" support (mirror-only of https://gitlab-ext.sigma-chemnitz.de/ensc/r-tftpd)

About

r-tftpd is a tftp server with RFC 7440 "windowsize" support and it can relay tftp requests to http servers.

It allows RRQ (read) requests; WRQ support is incomplete and exists only for testing purposes.

Implemented standards

• RFC 1350 "THE TFTP PROTOCOL":

  • RRQ: yes
  • WRQ: only for testing purposes; e.g. accepts only the data but does not store it. No window size support either
  • implements only the "octet" ("binary") transfer mode; "netascii" and "mail" are not supported
  • block ids will wrap around from 65535 to 0

• RFC 2347 "TFTP Option Extension":

  • can be disabled (for testing purposes) by the --no-rfc2347 flag

• RFC 2348 "TFTP Blocksize Option"

• RFC 2349 "TFTP Timeout Interval and Transfer Size Options"

• RFC 7440 "TFTP Windowsize Option"

  • only for RRQ, but not for WRQ

Usage

Usage: r-tftpd [OPTIONS]

Options:
  -s, --systemd                use systemd fd propagation
  -p, --port <PORT>            port to listen on [default: 69]
  -l, --listen <IP>            ip address to listen on [default: ::]
  -m, --max-connections <NUM>  maximum number of connections [default: 64]
  -t, --timeout <TIMEOUT>      timeout in seconds during tftp transfers [default: 3]
  -f, --fallback <URI>         fallback uri
  -L, --log-format <FMT>       log format [default: default] [possible values: default, compact, full, json]
  -C, --cache-dir <DIR>        directory used for cache files
      --no-rfc2347             disable RFC 2347 (OACK) support; only useful for testing some clients
      --wrq-devnull            accept WRQ but throw it away; only useful for testing some clients
      --disable-proxy          disable proxy support
  -h, --help                   Print help information
  -V, --version                Print version information

build

make
cargo build

see r-tftp.spec for ways how to customize it by using makefile variables.

standalone

cd /var/lib/tftpboot && r-tftpd --port 1234

Listening on privileged ports (e.g. the standard 69 one) requires the CAP_NET_BIND_SERVICE capability (see man 7 capabilities).

systemd socket activation

see contrib/

Proxy mode

"r-tftpd" supports relaying of tftp requests to other servers. It allows pseudo virtual hosting by creating (dead) symlinks pointing to an url.

supported uris

• http:// + https://

Schemes accept the following, "plus" sign separated modifiers:

• nocache: downloaded resources will not be cached; by default usual http caching mechanisms (Cache-Control, Etag, ...) are applied and resources are kept locally. They are not accessible on disk but created by O_TMPFILE.

  The cache is cleared periodically

• nocompress: resources are requested with identity encoding; by default, compression is enabled. When compression is enabled, the whole file must be downloaded when starting the transaction because its size can not be determined else.

Without compression, Content-Length information are used and tftp upload and http download happen in parallel, This helps to avoid tftp timeouts

examples

$ tree
.
├── domain1 -> http+nocache://domain1.example.org/
├── domain2 -> http+nocompress://domain2.example.org/
├── existing
├── remote-file -> http+nocompress+nocache://domain3.example.org/some-file
└── subdir
    └── file

$ r-tftp --fallback http://fallback.example.org/

requested path	returned resource	flags
existing	local existing file
subdir/file	local subdir/file
domain1/foo	remote http://domain1.example.org/foo	without caching
domain2/bar	remote http://domain2.example.org/bar	without http compression
remote-file	remote http://fallback.example.org/remote-file	without http compression nor caching
not-here	remote http://fallback.example.org/not-here

License

GPL-3.0 or later