Our home automation presence is maintained through an Android app, OwnTracks, which updates a Mosquitto server via a WebSockets reverse proxy. Mosquitto runs on a Fedora 25 server and was installed from the default RPM repository.

Recently, we stopped receiving location updates – both of our Android clients were stuck “Connecting” to the MQTT server. Nothing appeared in the Apache access or error logs, and capturing network traffic only got a small number of packets (TCP session overhead ‘stuff’). Even bypassing the reverse proxy and using the internal network to communicate directly to the Mosquitto server only created a couple of packets. Using a test client (http://www.hivemq.com/demos/websocket-client/), I saw strange connection failures — so I knew the problem was not specific to the OwnTracks client.

It seems there was a bug in libwebsockets v2.1.1 (and possibly others) — when we updated our Fedora installation, the new libwebsockets broke our MQTT over WebSockets. Currently, the Fedora repository still contains an impacted version of libwebsockets. To resolve the issue, I built the latest stable libwebsockets and built mosquitto against this updated library.

Process: The first step is to remove the dnf managed packages (rpm -e libwebsockets libwebsockets-devel mosquitto). Then build libwebsockets and mosquitto.

To Build LibWebSockets:

wget https://github.com/warmcat/libwebsockets/archive/master.zip
unzip master.zip
cd libwebsockets-master/
mkdir build
cd build
cmake ..
make
make install
cp libwebsockets.pc /usr/lib/
cp lws_config.h /usr/include/
cp ../lib/libwebsockets.h /usr/include/
cp ./lib/libwebsockets.so /usr/lib/

To Build Mosquitto:

wget https://github.com/eclipse/mosquitto/archive/master.zip
unzip master.zip
cd mosquitto-1.4.11
vi config.mk # Line 68, change to “WITH_WEBSOCKETS:=yes”
make
make install

Start the Mosquitto server and try again. Voila, presence works again!