php conditional loop question

ok. This is probably simple but I am not thinking straight. Here is what I want to do I have a function that makes a connection to a live datafeed website and downloads data via a pfsockopen() statement. After awhile the data stops feeding but the connection stays open. when the data stops I want to exit out of the function and have the function run again basically i don't know how to exit out of the function and have the program run the function again I have the program downloading the data and all that so I don't need help with that. I just want to be able to reun the function if the data stops or in more general a certain condition is met. any ideas and comments would be greatly appreciated. Randy