Date: Tue, 11 Oct 2005 10:10:19 GMT From: Kris Kennaway <kris@obsecurity.org> To: freebsd-bugs@FreeBSD.org Subject: Re: kern/87194: fxp(4) promiscuous mode seems to corrupt hw-csum Message-ID: <200510111010.j9BAAJne072187@freefall.freebsd.org>
next in thread | raw e-mail | index | archive | help
The following reply was made to PR kern/87194; it has been noted by GNATS. From: Kris Kennaway <kris@obsecurity.org> To: Brian Fundakowski Feldman <green@FreeBSD.org> Cc: FreeBSD-gnats-submit@FreeBSD.org Subject: Re: kern/87194: fxp(4) promiscuous mode seems to corrupt hw-csum Date: Tue, 11 Oct 2005 05:33:27 -0400 On Mon, Oct 10, 2005 at 02:32:26AM -0400, Brian Fundakowski Feldman wrote: > > >Number: 87194 > >Category: kern > >Synopsis: fxp(4) promiscuous mode seems to corrupt hw-csum > >Confidential: no > >Severity: serious > >Priority: medium > >Responsible: freebsd-bugs > >State: open > >Quarter: > >Keywords: > >Date-Required: > >Class: sw-bug > >Submitter-Id: current-users > >Arrival-Date: Mon Oct 10 06:40:10 GMT 2005 > >Closed-Date: > >Last-Modified: > >Originator: Brian Fundakowski Feldman > >Release: FreeBSD 6.0-RC1 i386 > >Organization: > >Environment: > System: FreeBSD rex.vetinsite.net 6.0-RC1 FreeBSD 6.0-RC1 #2: Sun Oct 9 21:16:52 EDT 2005 root@:/usr/obj/usr/src/sys/REX i386 > > fxp0: <Intel 82551 Pro/100 Ethernet> port 0xcc00-0xcc3f mem 0xfe6fe000-0xfe6fefff,0xfe6a0000-0xfe6bffff irq 17 at device 1.0 on pci3 > miibus0: <MII bus> on fxp0 > fxp0: Ethernet address: 00:04:23:b3:37:55 > fxp0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 > options=b<RXCSUM,TXCSUM,VLAN_MTU> > inet6 fe80::204:23ff:feb3:3755%fxp0 prefixlen 64 scopeid 0x2 > inet ... > ether 00:04:23:b3:37:55 > media: Ethernet autoselect (100baseTX <full-duplex>) > status: active > >Description: > When turning promiscuous mode on, e.g. with bridging, the > tcpdump output for every packet shows an invalid checksum. > Now, this is not that strange in the face of hardware > checksumming, but the interface is also unusable in some > unknown capacity -- some things seem to work, other things > don't. I don't know whether packets are not being sent > or they're being sent with actual bad checksums. tcpdump on another machine and see what the packets actually are. If your NIC is doing hardware checksumming, it's expected that tcpdump will not see it, and so will conclude the checksums are bad. Kris
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200510111010.j9BAAJne072187>