pacredir
pacredir - redirect pacman requests, assisted by mDNS Service Discovery
By default every Arch Linux ↗️ installation downloads its package files from online mirrors, transferring all the bits via WAN connection.
But often other Arch systems may be around that already have the files
available on local storage - just a fast LAN connection away. This is
where pacredir can help.
It uses mDNS Service Discovery ↗️
by systemd-resolved ↗️
to find other instances and redirect pacman there if available.
Use at your own risk, pay attention to license and warranty, and disclaimer on external links!
Requirements
To compile and run pacredir you need:
And these are build time or make dependencies:
- markdown ↗️ (HTML documentation)
- librsvg ↗️ (render the favicon)
- oxipng ↗️ (optimize the favicon)
Arch Linux installs development files for the packages by default, so
no additional development packages are required.
Build and install
Building and installing is very easy. Just run:
make
followed by:
make install
This will place an executable at /usr/bin/pacredir,
documentation can be found in /usr/share/doc/pacredir/.
Additionally systemd service files are installed to
/usr/lib/systemd/system/.
You can not have systemd-resolved and the avahi daemon announce services
at the same time. If you really, really need the avahi daemon running
install the compatibility files:
make install-avahi
ℹ️ Info: This is packaged as
pacredir(andpacredir-avahifor the compatibility files) in Arch Linux ↗️ and derived distributions. Install with:
pacman -Syu pacredir
Usage
Make sure mDNS is enabled in systemd-resolved, and also make sure it
is enabled for all interface you want to use this with. Run resolvectl
to get an overview.
Then enable and start systemd services pacserve and pacredir, allow
TCP port 7078 in your firewall and add the following line to your
repository definitions in pacman.conf:
Include = /etc/pacman.d/pacredir
To get a better idea what happens in the background have a look at the request flow chart.
Status page
A simple status page is available when pacredir is running. Just point
your browser to your local instance.
The instance is listening on localhost only. To access it from a different
host you need to proxy (for example reverse proxy with nginx) or tunnel
it. The latter can be used ad hoc, for example with ssh local forwarding:
ssh -L 17077:localhost:7077 host
Then point your browser to http://localhost:17077/. A desktop file for
that url is installed, so your desktop environment has a shortcut.
Databases from cache server
By default databases are not fetched from cache servers. To make that
happen just add the server twice, additionally as regular server. This
is prepared in /etc/pacman.d/pacredir, just uncomment the corresponding
line.
Do not worry if pacman reports the following after the change:
error: failed retrieving file 'core.db' from 127.0.0.1:7077 : The requested URL returned error: 404 Not Found
This is ok, it just tells pacman that pacredir could not find a file
and downloading it from an official server is required.
Please note that pacredir redirects to the most recent database file
found on the local network if it is not too old (currently 24 hours). To
make sure you really do have the latest files run pacman -Syu twice.
Security
There is no security within this project, information and file content
is transferred unencrypted and unverified. Anybody is free to serve
broken and/or malicious files to you, but this is by design. So make
sure pacman is configured to check signatures! It will then detect if
anything goes wrong.
Querying systemd-resolved
You may want to query systemd-resolved directly to verify the results.
This will list all instances:
resolvectl query --legend=false --protocol=mdns --type=PTR --synthesize=false --zone=false '_pacserve._tcp.local'
(The escape sequence \032 represents a space.)
For details on the services you can query each:
resolvectl service --legend=false 'pacserve on host._pacserve._tcp.local'
License and warranty
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
Disclaimer on external links
Our website contains links to the websites of third parties ("external links"). As the content of these websites is not under our control, we cannot assume any liability for such external content. In all cases, the provider of information of the linked websites is liable for the content and accuracy of the information provided. At the point in time when the links were placed, no infringements of the law were recognisable to us. As soon as an infringement of the law becomes known to us, we will immediately remove the link in question.
💡️ Hint: All external links are marked with an arrow pointing diagonally in an up-right (or north-east) direction (↗️).
Upstream
URL: GitHub.com
Mirror: eworm.de GitLab.com