irule decode

This could be simple irule, but i am new to it. Could you explain what this means?

when HTTP_REQUEST {

if {[HTTP::uri] contains "root" || [HTTP::uri] contains "wi-index.php"} { if {not[class match [IP::client_addr] equals Src_ip_Address] } {

log local0. "dropped connection [IP::client_addr]" reject } } }