µMurmur
µMurmur or uMurmur is a minimalistic Mumble (software) server primarily targeted to run on embedded devices with an open OS like OpenWrt.
Project page for more info and most up-to-date documentation at https://github.com/umurmur/umurmur
Preparation
Prerequisites
So far there are two uMurmur packages available in the repos, one compiled against the Mbed-TLS library and one against the OpenSSL library.
opkg info umurmur-mbedtls opkg info umurmur-openssl
Note that currently, the Mbed-TLS version does not auto-generate a certificate, causing it to not startup correctly. It is therefor suggested to use the OpenSSL version for the time being.
See this GitHub issue: https://github.com/openwrt/packages/issues/22188
Firewall: The default ports are 64738 tcp and 64738 udp. open them up in /etc/config/firewall.
Required Packages
The following list specifies package versions for latest stable release of OpenWrt. At time of writing, 23.05.
Server (OpenWrt)
| Name | Version | Size | Description |
|---|---|---|---|
| umurmur-openssl | 0.2.20-2 | 36762 | Minimalistic Mumble server daemon. Uses OpenSSL library for SSL and crypto. |
| libopenssl3 | 3.0.12-1 | 1394609 | The OpenSSL Project is a collaborative effort to develop a robust, commercial-grade, full-featured, and Open Source toolkit implementing the Secure Sockets Layer (SSL v2/v3) and Transport Layer Security (TLS v1) protocols as well as a full-strength general purpose cryptography library. This package contains the OpenSSL shared libraries, needed by other programs. |
| libconfig11 | 1.7.3-1 | 15719 | Libconfig is a simple library for manipulating structured configuration files. This file format is more compact and more readable than XML. And unlike XML, it is type-aware, so it is not necessary to do string parsing in application code. Libconfig is very compact -- just 38K for the stripped C shared library (less than one-fourth the size of the expat XML parser library) and 66K for the stripped C++ shared library. This makes it well-suited for memory-constrained systems like handheld devices. |
| libprotobuf-c | 1.4.1-1 | 9922 | Runtime library to use Google Protocol Buffers from C applications. Protocol Buffers are a way of encoding structured data in an efficient yet extensible format. Google uses Protocol Buffers for almost all of its internal RPC protocols and file formats. |
Client (your PC)
On Linux you need to install the mumble package, like this one. On Windows or MacOSX you have to download it: http://mumble.sourceforge.net/.
Note that uMurmur version 0.2.x is compatible with Mumble version 1.2.x series. Mumble version 1.1.x series is not compatible.
Installation
Example using shell access:
opkg install umurmur-openssl vi /etc/umurmur.conf /etc/init.d/umurmur enable /etc/init.d/umurmur start logread
Check log output that the uMurmurd started up OK.
open port 64738 for TCP and UDP in /etc/config/firewall.
vi /etc/config/firewall /etc/init.d/firewall reload
You should now be able to connect via the mumble protocol.
Configuration
cat /etc/umurmur.conf
max_bandwidth = 48000;
welcometext = “Welcome to uMurmur!”;
certificate = “/etc/umurmur/cert.crt”;
private_key = “/etc/umurmur/key.key”;
password = “”;
max_users = 10;
# Root channel must always be defined first.
# If a channel has a parent, the parent must be defined before the child channel(s).
channels = ( {
name = “Root”;
parent = “”;
description = “The Root of all channels”;
},
{
name = “Lobby”;
parent = “Root”;
description = “Lobby channel”;
},
{
name = “Red team”;
parent = “Lobby”;
description = “The Red team channel”;
},
{
name = “Blue team”;
parent = “Lobby”;
description = “The Blue team channel”;
}
);
# Channel links configuration.
channel_links = ( {
source = “Lobby”;
destination = “Red team”;
},
{
source = “Lobby”;
destination = “Blue team”;
}
);
default_channel = “Lobby”; |
Start on boot
To enable/disable start on boot:
/etc/init.d/umurmur enable this simply creates a symlink to umurmur in “/etc/rc.d/”
/etc/init.d/umurmur disable this removes the symlink again
Administration
There is no privilege system implemented in uMurmur version < 0.2.10 meaning that users cannot be kicked, banned or muted by other users. If you have a need for this kind of functionality the options are:
- Set a server password
- Add the IP of misbehaving users to your firewall.
Since uMurmur 0.2.10 there is a password based administration scheme. A package is available in OpenWRT trunk. For this to work you'd need to install the dependencies from trunk as well if you are running Backfire.
Troubleshooting
The most common error is the firewall. Double check connection problems with
iptables -n -v
and check those counters.
If users cannot connect and you get this error in the log
WARN: SSL handshake failed: -28672
you're probably running Backfire 10.03.1-rc4 with Polarssl 0.14. Upgrade to Backfire 10.03.1-RC5 or later.
Notes
- Read about certificates in general. Do it! Public key certificate
- enlighten your friends, there is no point in security if not all users understand the principle of operation
- Project Homepage: https://github.com/umurmur/umurmur