On Wed, 2007-05-02 at 14:48 +0300, Kalle Valo wrote: > > It would take modifications to the kernel - ideally some sort of DBUS > > message when a packet needs to be routed - but this would remove the > > need to hook into applications, and allow ANY app to generate a request > > for connection. > > Sounds a bit complicated to do this in kernel. How would the > application notify that it doesn't need the connection anymore? > You don't do it ALL in the kernel, hence my statement about DBUS. All the kernel needs to do is provide DBUS messages for: Outbound packet detected with interface down More than $TIME has elapsed without an outbound packet.
You could probably plug into iptables for this - just have an iptables plugin for generating a DBUS message on a matching packet. This has the advantage of being a nice general tool, which can be used for other things (e.g. notification of the firewall blocking a packet) as well. You then have an application watching for that event, and bringing up the connection dialog when needed. Once the connection is established, the application then: Signals the kernel to retry the packet Disables the iptables rule if needed. Watches the packet count on the interface to determine activity. When the packet count does not increase for some period of time, re-instate the iptables rule and down the interface. Of course, if the user forces the interface up directly, then all that becomes moot - you leave the interface up until it fails, or until the user tells you otherwise. > Sounds a bit complicated to do this in kernel. How would the > application notify that it doesn't need the connection anymore? The whole problem here is that the application *cannot* make the decision about whether the connection is needed, as it simply does not have the information needed. The application may know it wants to talk to a server, but the application may not know if that server is local to the device or remote, and requiring a connection - the browser being a perfect example of this. The browser would have to evaluate every host's address to determine routability - but that in and of itself may or may not require bringing up the interface to do a DNS query, and there is no way for the browser to know that until it does the query. And how can the application decide it does not need the connection? Again, to pick on the poor browser - how does the browser know that it is done loading the page? What if there is a META refresh on the page? What if there is AJAX running? All the application can say is that *at this moment* it doesn't need a connection. _______________________________________________ maemo-developers mailing list maemo-developers@maemo.org https://maemo.org/mailman/listinfo/maemo-developers
