You can send clients customised messages by sending data into a named pipe. (Or fd 3 with the onconnect/ondisconnect/pre_commandon/pre_commandoff commands).
Data sent to the FIFO starts with a username or pid (as for admin commands8) followed by a colon and then the text message. The username can be an ordinary user or a meta-user8 like %con (which matches all CONNECTed users).
The text data should start with '#' otherwise some clients will exit, thinking it's an error message. The message should also end in a newline. (Echo does this by default). Messages sent in ip-up after sending SIGUSR2 to dwun will not be seen; send them before you send that signal. It is safe to send a message after SIGUSR1 or SIGINT.
For example, to send ``#Hello my pretties'' to all CONNECTed users,
echo '%con:#Hello my pretties' > /usr/lib/dwun-msgUsing fd 3 this would be
echo '%con:#Hello my pretties' >&3Make sure each line is below 512 characters in length.