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A daemon for continuously opening ports via UPnP.
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.
upnp-daemon can be installed easily through Cargo via crates.io:
shell script
cargo install --locked upnp-daemon
Please note that the --locked flag is necessary here to have the exact same
dependencies as when the application was tagged and tested. Without it, you
might get more up-to-date versions of dependencies, but you have the risk of
undefined and unexpected behavior if the dependencies changed some
functionalities. The application might even fail to build if the public API of
a dependency changed too much.
Alternatively, pre-built binaries can be downloaded from the GitHub releases page.
```text
Usage: upnp-daemon [OPTIONS] --file
Options:
-f, --file
In the most basic case, a call might look like so:
shell script
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 by default
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:
shell script
kill $(</tmp/upnp-daemon.pid)
If you want the PID to be written to another file, maybe because you want to
have multiple running instances intentionally, or because your daemon watcher
expects the file in another place, you can use the --pid-file option to
choose your own file path. Due to technical reasons, this PID file must always
be given as an absolute path. Please be aware that this application does not
create folders, so the parent folder of the PID file needs to exist
beforehand. Also, of course, the user running the application needs to have
write permission to the folder.
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).
Therefore, you will also not see the --pid-file option on Windows since it
has no use there.
Depending on the actual use case, there might be the need to read in the ports configuration from stdin. In this case, you can give the pseudo filename "-", like so:
shell script
generate-configuration | upnp-daemon --file -
The configuration generated by the imaginary generate-configuration needs to
have the same format as described in chapter config file
format.
Note: If you actually want to read in a file with the name -, give it as
an absolute or relative file path, like so:
shell script
upnp-daemon --file ./-
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:
shell script
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.
If you just want to test your configuration, without letting the daemon run
forever, you can use the oneshot flag, like so:
shell script
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.
If you want to close your opened ports when the program exits, you can use the
close-ports-on-exit flag, like so:
shell script
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:
shell script
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.
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:
shell script
RUST_LOG=info upnp-daemon --foreground --file ports.csv
To make the logger even more verbose, try to set the log level to debug:
shell script
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.
The config file can be given as either CSV (default for now) or JSON (with
--format json). The names and contents of the fields are always the same.
The format of the port mapping file is a simple CSV file, like the following example:
text
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.
With the --csv-delimiter option, you can choose an arbitrary character to be
used as a field delimiter in your CSV file. By default, we use the semicolon,
but if you instead prefer a usual comma, you can just say so with
--csv-delimiter ','.
Please be aware that your shell might interpret the delimiter (for example, the semicolon is used in bash to separate two commands), so be sure to correctly escape it.
A config file in JSON format with the above contents could look like this:
json
[
{
"address": "192.168.0.10",
"port": 12345,
"protocol": "UDP",
"duration": 60,
"comment": "Test 1"
},
{
"address": null,
"port": 12346,
"protocol": "TCP",
"duration": 60,
"comment": "Test 2"
}
]
The line breaks and indentations are just for readability, you can format it any way you like. You can even go as far and feed in a single line, as long as it is a valid JSON array with all required fields in it.
Since address is null in the second entry, it can also be left out
completely if you prefer. Also, any key that is not documented below will be
silently ignored, so you might use them as internal comments for yourself. So
a config might also look like:
json
[
{
"rationale": "This port is needed for an awesome application!",
"may-be-deleted": false,
"port": 12347,
"protocol": "TCP",
"duration": 60,
"comment": "Test 3"
}
]
The keys rationale and may-be-deleted will be ignored by the daemon.
Also, please note that even if you want to add just one port mapping, you need to specify a JSON array.
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.
You can also enter the IP address in CIDR notation. In that case, the IP range is checked against all connected interfaces and only matching ones are considered. This is useful if you don't know your current IP address (or it might change from time to time), but you know the DHCP configuration of your router.
Such an IP address might be 192.168.0.10 or 192.168.0.0/24 or even
192.168.0.
More examples can be found in the responsible library's documentation: https://docs.rs/cidr-utils/0.5.10/cidr_utils/index.html
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.