function::tcpmib_filter_key.3stap man page
function::tcpmib_filter_key — Default filter function for tcpmib.* probes
pointer to the struct sock being acted on
value to be counted if sk passes the filter
This function is a default filter function. The user can replace this function with their own. The user-supplied filter function returns an index key based on the values in sk. A return value of 0 means this particular sk should be not be counted.