SoulSpark
Software
www.skarnet.org

The souldrain program

souldrain is an UCSPI client application that maintains a NetSoul connection open, and regularly checks network connectivity.

Interface

     souldrain [ -T x+y ] [ -t c ] [ -i k ] ip:port [ ip:port ... ]

• souldrain talks with a NetSoul server on fds 6 (for reading) and 7 (for writing).
• souldrain reads and immediately forgets anything the server sends.
• If the server closes the connection, souldrain exits.
• Every k seconds, souldrain sends a keepalive message to the server. By default, k is 570.
• Every c seconds, souldrain spawns a tcpping child, on the ip:port list, with the -T x+y option. If tcpping exits anything else than 0, souldrain exits. By default, c is 40, x is 2 and y is 10.

Notes

souldrain will run exactly as long as the NetSoul server works and maintains network connectivity. If your ip:port list is properly crafted, a dying souldrain means that the network is down for you, and it's time to rerun your NetSoul authentication sequence.
The service/soulspark/run file shows an example of tcpclient + soulspark + souldrain combination, which reliably maintains the network when run under a supervisor.