Date: Wed, 30 Dec 2009 10:40:04 GMT From: Dennis Yusupoff <dyr@smartspb.net> To: freebsd-net@FreeBSD.org Subject: Re: kern/141843: [em] [vlan] Intel txcsum and assigned vlan invoke wrong dst MAC in TCP packets Message-ID: <200912301040.nBUAe4YN074722@freefall.freebsd.org>
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The following reply was made to PR kern/141843; it has been noted by GNATS. From: Dennis Yusupoff <dyr@smartspb.net> To: pyunyh@gmail.com Cc: bug-followup@FreeBSD.org Subject: Re: kern/141843: [em] [vlan] Intel txcsum and assigned vlan invoke wrong dst MAC in TCP packets Date: Wed, 30 Dec 2009 13:34:30 +0300 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig42235F443B11536DEDB37A0B Content-Type: multipart/alternative; boundary="------------060207040500050208050702" This is a multi-part message in MIME format. --------------060207040500050208050702 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable 29.12.2009 21:51, Pyun YongHyeon ?????: > On Mon, Dec 21, 2009 at 11:53:22PM +0000, linimon@freebsd.org wrote: > =20 >> Old Synopsis: Intel txcsum and assigned vlan invoke wrong dst MAC in T= CP packets >> New Synopsis: [em] [vlan] Intel txcsum and assigned vlan invoke wrong = dst MAC in TCP packets >> >> Responsible-Changed-From-To: freebsd-bugs->freebsd-net >> Responsible-Changed-By: linimon >> Responsible-Changed-When: Mon Dec 21 23:51:33 UTC 2009 >> Responsible-Changed-Why:=20 >> Over to maintainer(s). >> >> http://www.freebsd.org/cgi/query-pr.cgi?pr=3D141843 >> =20 > I'm not sure whether you're seeing one of edge case of em(4)/igb(4) > checksum offload issue. Personally I couldn't reproduce the issue > but I guess the checksum offload/TSO handling might cause > unexpected result. If you disable Tx checksum offload or TSO em(4) > work as expected, right?=20 Not exactly. Only checksum offload gives this issue, TSO on/off doesn't matter. By the way, we checked UDP also and found something interested. For it, we run echo service on server ("|echo dgram udp wait =20 root internal|" in //etc/inetd.conf/) and send strings by "|nc -4 -u server 7|" from client. So...UDP works fine before, while and after "ifconfig vlanX vlan X vlandev em0" command given at server. And the most interesting things is what while server "hangs" for TCP-connections, "establishing" UDP connections between client and server...helps it to "unhang" TCP, so it begins to works correctly. > If so, would you try the following patch > and let me know whether it makes any difference? > > http://people.freebsd.org/~yongari/em.csum_tso.20091229.patch > =20 Doesn't help, same behavior. And moreover, UDP also doesn't "help" and doesn't work so. If you'd like, I could give you an access to this server via SSH, would y= ou? --------------060207040500050208050702 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta content=3D"text/html; charset=3DISO-8859-1" http-equiv=3D"Content-Type"> <title></title> </head> <body bgcolor=3D"#ffffff" text=3D"#000000"> 29.12.2009 21:51, Pyun YongHyeon пишет: <blockquote cite=3D"mid:20091229185119.GF1166@michelle.cdnetworks.com" type=3D"cite"> <pre wrap=3D"">On Mon, Dec 21, 2009 at 11:53:22PM +0000, <a class=3D"mo= z-txt-link-abbreviated" href=3D"mailto:linimon@freebsd.org">linimon@freeb= sd.org</a> wrote: </pre> <blockquote type=3D"cite"> <pre wrap=3D"">Old Synopsis: Intel txcsum and assigned vlan invoke wr= ong dst MAC in TCP packets New Synopsis: [em] [vlan] Intel txcsum and assigned vlan invoke wrong dst= MAC in TCP packets Responsible-Changed-From-To: freebsd-bugs->freebsd-net Responsible-Changed-By: linimon Responsible-Changed-When: Mon Dec 21 23:51:33 UTC 2009 Responsible-Changed-Why:=20 Over to maintainer(s). <a class=3D"moz-txt-link-freetext" href=3D"http://www.freebsd.org/cgi/que= ry-pr.cgi?pr=3D141843">http://www.freebsd.org/cgi/query-pr.cgi?pr=3D14184= 3</a> </pre> </blockquote> <pre wrap=3D""> I'm not sure whether you're seeing one of edge case of em(4)/igb(4) checksum offload issue. Personally I couldn't reproduce the issue but I guess the checksum offload/TSO handling might cause unexpected result. If you disable Tx checksum offload or TSO em(4) work as expected, right? </pre> </blockquote> Not exactly.<br> Only checksum offload gives this issue, TSO on/off doesn't matter.<br> By the way, we checked UDP also and found something interested.<br> For it, we run echo service on server ("<code>echo dgra= m udp wait root internal</code>" in <= i>/etc/inetd.conf</i>) and send strings by "<code>nc -4 -u server 7</code>" from client.<br> So...UDP works fine before, while and after "ifconfig vlanX vlan X vlandev em0" command given at server. And the most interesting things is what while server "hangs" for TCP-connections, "establishing" UDP connections between client and server...helps it to "unhang" TCP, so it begins to works correctly.<br> <br> <blockquote cite=3D"mid:20091229185119.GF1166@michelle.cdnetworks.com" type=3D"cite"> <pre wrap=3D"">If so, would you try the following patch and let me know whether it makes any difference? <a class=3D"moz-txt-link-freetext" href=3D"http://people.freebsd.org/~yon= gari/em.csum_tso.20091229.patch">http://people.freebsd.org/~yongari/em.cs= um_tso.20091229.patch</a> </pre> </blockquote> Doesn't help, same behavior. And moreover, UDP also doesn't "help" and doesn't work so.<br> <br> If you'd like, I could give you an access to this server via SSH, would you?<br> </body> </html> --------------060207040500050208050702-- --------------enig42235F443B11536DEDB37A0B Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBAgAGBQJLOyy2AAoJEBUTaqBS2NB4Le8IAIkQsJHiS2y3JjHRmYK/2OFz jHtHZGOnWw8cHzR275Sr75Os1z8hTJCwDhPwaMaqAr45pA+zg6E9QkKlr3ZbEPgW PNoxdIo+HN7xqJFAt9ye8BviE/HC0gelRSf0rUdc+qS2sR1MH7Pwa8uNwgg1/bpy BMNPWBjCAmsvx5AyaUi7zuGDzhz0UUMcO+k7DlXnJO1GX8ABR6T4mdU2ZzXYGGk7 e5oaT2++ezm5nKN/ABfseQ3UXzG10gv7N0H+4FpWJD5H1lm0pw3tphHGehzbwzBV 6YZmMYq0dHw+E4X5Ybbxe/jnrEsw2aeZdDIfBEqyOgGsudW/7j9zF/VsJPbY57g= =tVqG -----END PGP SIGNATURE----- --------------enig42235F443B11536DEDB37A0B--
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