kern/141843: [em] [vlan] Intel txcsum and assigned vlan invoke wrong dst MAC in TCP packets

[Dennis Yusupoff]

The following reply was made to PR kern/141843; it has been noted by GNATS.

From: Dennis Yusupoff <dyr at smartspb.net>
To: pyunyh at gmail.com, bug-followup at FreeBSD.org
Cc:  
Subject: Re: kern/141843: [em] [vlan] Intel txcsum and assigned vlan invoke
 wrong dst MAC in TCP packets
Date: Mon, 11 Jan 2010 12:20:46 +0300

 30.12.2009 23:20, Pyun YongHyeon пишет:
 >
 > Sorry, that wasn't expected one. From your explanation above I
 > think I found a possible cause of checksum offload issue of em(4).
 > The issue was not I initially thought though. It seems the checksum
 > offload context configured in em(4) was incorrectly reused even if
 > a frame requires a new context as IP/TCP header length, checksum
 > offload offset was changed. Setting up new context put more burden
 > to hardware such that em(4) used to avoid new context setup as
 > possible as it can. However it seems em(4) failed to compare all
 > required field in the checksum offload context. Would you try the
 > following patch again?
 >
 > http://people.freebsd.org/~yongari/em.csum_tso.20091230.patch
 Gotcha!
 It works!
 
 ---
 With best regards,
 Dennis Yusupoff,
 network engineer of
 Smart-Telecom ISP
 Russia, Saint-Petersburg