[piksi_multi_cpp] Robustify UDP broadcasting and receiving

[rikba]

UDP broadcasting

During startup of the base station the broadcasting fails, if no interface is up, yet. We could implement a timeout, or watchdog for new interfaces.

UDP receiving

It seems like the UDP correction receiver fails to receive corrections if the WiFi correction breaks. The corrections do not come back if WiFi is returned. Could this be? @michaelpantic

@fabioruetz, @clanegge can you validate these issues when you go testing next time?

[chrissunny94]

Hey dudes i am getting the following error .

`roslaunch piksi_multi_cpp config.launch config_type:=rover 
... logging to /home/pratcha/.ros/log/22b79aae-bccc-11ed-ae71-6fe92d02df3d/roslaunch-cgsclxr79748600-601412.log
Checking log directory for disk usage. This may take a while.
Press Ctrl-C to interrupt
WARNING: disk usage in log directory [/home/pratcha/.ros/log] is over 1GB.
It's recommended that you use the 'rosclean' command.

started roslaunch server http://cgsclxr79748600:37151/

SUMMARY
========

PARAMETERS
 * /piksi_multi_config/config_type: rover
 * /piksi_multi_config/device_ids: serial:///dev/tty...
 * /rosdistro: noetic
 * /rosversion: 1.15.15

NODES
  /
    piksi_multi_config (piksi_multi_cpp/piksi_multi_config)

ROS_MASTER_URI=http://localhost:11311

process[piksi_multi_config-1]: started with pid [601441]
[ INFO] [1678184339.417862873]: serial:///dev/ttyUSB0@115200
[ INFO] [1678184339.419274228]: Opened port: /dev/ttyUSB0
[ INFO] [1678184339.429032406]: Opening config: /home/pratcha/catkin_ws/src/ethz_piksi_ros/piksi_multi_cpp/cfg/config_rover_2_4_20.ini
[ERROR] [1678184343.322244175]: Did not receive write response uart1.mode.SBP
[ WARN] [1678184343.417559626]: Error sbp_process: -2
[ERROR] [1678184344.397085123]: Did not receive write response uart1.baudrate.230400
[ERROR] [1678184345.509675652]: Did not receive write response uart1.flow_control.None
[ERROR] [1678184346.594456070]: Did not receive write response tcp_server0.enabled_sbp_messages.
[ERROR] [1678184347.709145806]: Did not receive write response tcp_server0.port.55555
[ERROR] [1678184348.794069222]: Did not receive write response tcp_server0.mode.SBP
[ERROR] [1678184349.859819438]: Did not receive write response tcp_server1.enabled_sbp_messages.
[ERROR] [1678184350.894352020]: Did not receive write response tcp_server1.port.55556
^C[piksi_multi_config-1] killing on exit
`