Re: kern/53562: bridge(4) breaks segmentation / TX checksum offloading

[Christoph Badura <bad%bsd.de@localhost>]

The following reply was made to PR kern/53562; it has been noted by GNATS.

From: Christoph Badura <bad%bsd.de@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: Rin Okuyama <rokuyama%rk.phys.keio.ac.jp@localhost>,
	Masanobu SAITOH <msaitoh%execsw.org@localhost>,
	Ryota Ozaki <ozaki-r%netbsd.org@localhost>
Subject: Re: kern/53562: bridge(4) breaks segmentation / TX checksum
 offloading
Date: Wed, 3 Apr 2019 00:58:41 +0200

 There is one more problem:
 
 We use the same bits in csum_flags to indicate both that the hardware
 *needs to do* offloading and that the hardware *has done* offloading.
 
 IIRC, this wasn't a problem when this interface was introduced, because we
 didn't have bridge(4) yet and packets would either travel down the stack
 from kernel to harware or up the stack from hardware to kernel only.
 
 Adding bridge(4) changed that, hence the problems.
 
 To finaly resolve that for good we need separate flags to indicate that
 the hardware did offloading and what the status of that is.
 
 --chris