Re: kern/48104: Incorrect forwarding of broadcast packets by bridge(4)

[Ryota Ozaki <ozaki-r%iij.ad.jp@localhost>]

(2014/02/21 9:25), Lloyd Parkes wrote:
> Hi all,
> I finally got around to running the last test on my changes to bridge(4) and 
> it all works well.
> 
> The only real problem I had to think about was that the point in the network 
> stack for tapping off bridged packets was above the point in the network 
> stack where packets are injected. This means that when multicasting packets 
> up the network stack you have to do something to prevent a packet storm. My 
> initial implementation used a link local mbuf flag, but bridging is 
> inherently not link local, so I discarded that method. 
> 
> I settled on moving the point at which the bridge taps into the network stack 
> down the stack so that it is now below the point at which packets are 
> injected into the stack. In particular, I removed the bridge code from 
> ether_input() and made the bridge update the struct ifnet if_input field when 
> an interface is added to or removed from a bridge. The code for updating the 
> if_input field is purposefully simple and conservative.
> 

I prefer this reconstruction of ether_input and bridge_input.
Actually I (and my coworker) are thinking the approach to make
the part simple.

I'm checking and testing your patch.

> There are some interface drivers that call ether_input() directly instead of 
> indirecting through struct ifnet if_input and that seems to be a requirement 
> that was missed when porting the drivers from FreeBSD. I’ll PR those drivers 
> once I finish this email and send this patch to kern/48104.
> 
> Overall this patch removes 107 of old code and adds 85 lines of new code. I 
> know it’s a crude code metric, but I do like increased functionality with 
> less code.

me too :)

Regards,
  ozaki-r

> 
> Cheers,
> Lloyd