getting source/destination ip-address/port number in plugin

[Gaurav Bansal]

hi all,
I am writing a plugin and need the value of client/server
ip-address/port-number. Is there any existing api, using which i can get
these OR any structure from which i can get these values ? Definitely these
would have been stored in some structure while parsing the ip headers, just
want to know how to access them from the plugin.
thanks,
gaurav