Crate upnp_daemon[−][src]

UPnP daemon

A daemon for continuously opening ports via UPnP.

Motivation

There are quite some programs out there that need certain network ports to be open to work properly, but do not provide the capability for opening them automatically via UPnP. Sure, one could always argue about the security implications that come with UPnP, but if you are willing to take the risk, it is just annoying, that for example your webserver is not reachable from the internet, because you forgot to open port 80, or your router rebooted and cleared the table of open ports. Or your machine does for whatever reason not have a static IP address, so you cannot add a consistent port mapping.

Because of this frustration, I created upnp-daemon, a small service written in Rust, that will periodically check a file with your defined port mappings and send them to your router. The main usage will be that you start it once and let it run as a background service forever. The file with the port mappings will be newly read in on each iteration, so you can add new mappings on the fly.

Installation

upnp-daemon can be installed easily through Cargo via crates.io:

cargo install upnp-daemon

Usage

In the most basic case, a call might look like so:

upnp-daemon --file ports.csv

This will start a background process (daemon) that reads in port mappings from a CSV file (see config file format) every minute and ask the appropriate routers to open those ports.

The PID of the process will be written to /tmp/upnp-daemon.pid and locked exclusively, so that only one instance is running at a time. To quit it, kill the PID that is written in this file.

Bash can do it like so:

kill $(</tmp/upnp-daemon.pid)

A note to Windows users: The daemonize library that is used to send this program to the background, does only work on Unix like systems. You can still install and use the program on Windows, but it will behave as if you started it with the --foreground option (see below).

Foreground Operation

Some service monitors expect services to start in the foreground, so they can handle them with their own custom functions. For this use case, you can use the foreground flag, like so:

upnp-daemon --foreground --file ports.csv

This will leave the program running in the foreground. You can terminate it by issuing a SIGINT (Ctrl-C), for example.

A note to Windows users: This option flag does not exist in the Windows version of this program. Instead, foreground operation is the default operation mode, since due to technical limitations, it cannot be sent to the background there.

Oneshot Mode

If you just want to test your configuration, without letting the daemon run forever, you can use the oneshot flag, like so:

upnp-daemon --foreground --oneshot --file ports.csv

You could of course leave off the foreground flag, but then you will not know when the process has finished, which could take some time, depending on the size of the mapping file.

Closing Ports

If you want to close your opened ports when the program exits, you can use the close-ports-on-exit flag, like so:

upnp-daemon --close-ports-on-exit --file ports.csv

If the program later terminates, either by using the kill command or by sending a SIGINT in foreground mode, the currently defined ports in the configuration file will be closed. Errors will be logged, but are not fatal, so they will not cause the program to panic. Those errors might arise, for example, when a port has not been opened in the first place.

If you just want to close all defined ports, without even running the main program, you can use the --only-close-ports flag, like so:

upnp-daemon --foreground --only-close-ports --file ports.csv

The foreground flag here is optional, but it is useful if you need to know when all ports have been closed, since the program only terminates then.

Logging

If you want to activate logging to have a better understanding what the program does under the hood, you need to set the environment variable RUST_LOG, like so:

RUST_LOG=info upnp-daemon --foreground --file ports.csv

To make the logger even more verbose, try to set the log level to debug:

RUST_LOG=debug upnp-daemon --foreground --file ports.csv

Please note that it does not make sense to activate logging without using foreground, since the output (stdout as well as stderr) will not be saved in daemon mode. This might change in a future release.

Config File Format

The format of the port mapping file is a simple CSV file, like the following example:

address;port;protocol;duration;comment
192.168.0.10;12345;UDP;60;Test 1
;12346;TCP;60;Test 2

Please note that the first line is mandatory at the moment, it is needed to accurately map the fields to the internal options.

Fields

  • address

    The IP address for which the port mapping should be added. This field can be empty, in which case every connected interface will be tried, until one gateway reports success. Useful if the IP address is dynamic and not consistent over reboots.

    Fill in an IP address if you want to add a port mapping for a foreign device, or if you know your machine’s address and want to slightly speed up the process.

  • port

    The port number to open for the given IP address. Note that upnp-daemon is greedy at the moment, if a port mapping is already in place, it will be deleted and re-added with the given IP address. This might be configurable in a future release.

  • protocol

    The protocol for which the given port will be opened. Possible values are UDP and TCP.

  • duration

    The lease duration for the port mapping in seconds. Please note that some UPnP capable routers might choose to ignore this value, so do not exclusively rely on this.

  • comment

    A comment about the reason for the port mapping. Will be stored together with the mapping in the router.

Structs

Cli
Options

Enums

PortMappingProtocol