> > This makes bridge port status reflect both the > > state of the interface from software (up/down) > > and the carrier. It makes STP handle link failure > > (cable breakage, etc). > > nice. Does this entrench STP further in the kernel? > Still planning to move it out to user space? > Even if STP were implemented in user space, this part should be done in the kernel to make sure that there is no window of time for a packet to be received or transmitted after the link state changes. Cable failure is not the worst problem here. Imagine some dunce pulling out a cable, realizing he pulled the wrong one, and then plugging it back into the wrong port. If he has created a loop in the network, even a single packet getting through can cause problems. One could be really paranoid and flush the hardware transmit queue too. Is there a way to do that for a port from the bridge driver? (Or should the device drivers do that anyway after a link change?) Are there any ethernet controllers that can automatically disable tx/rx after a link change, requiring the driver to reenable them? That would also be useful.
