Date: Thu, 25 Mar 2010 12:20:14 -0400 From: Boris Kochergin <spawk@acm.poly.edu> To: freebsd-net@freebsd.org Subject: Re: CARP vs. if_bridge Message-ID: <4BAB8D3E.9030404@acm.poly.edu> In-Reply-To: <4B7EA31A.3080204@acm.poly.edu> References: <4B7D72BF.1040104@acm.poly.edu> <201002191421.28699.max@love2party.net> <4B7EA31A.3080204@acm.poly.edu>
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Boris Kochergin wrote: > Max Laier wrote: >> On Thursday 18 February 2010 18:02:55 Boris Kochergin wrote: >> >>> Ahoy. I'm seeing what appears to be erroneous interaction between CARP >>> and if_bridge on multiple machines with a variety of Ethernet >>> controllers and architectures. I've observed it on 7.2-R and 8.0-R. The >>> test setup is simple enough: >>> >>> CARP master: >>> >>> FreeBSD t30 8.0-RELEASE-p1 FreeBSD 8.0-RELEASE-p1 #5: Sun Feb 14 >>> 20:22:41 EST 2010 root@t30:/usr/obj/usr/src/sys/T30 i386 >>> >>> lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384 >>> options=3<RXCSUM,TXCSUM> >>> inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1 >>> inet6 ::1 prefixlen 128 >>> inet 127.0.0.1 netmask 0xff000000 >>> dc0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> >>> metric 0 >>> mtu 1500 >>> options=8<VLAN_MTU> >>> ether 00:04:5a:a8:e0:bf >>> inet 192.168.0.2 netmask 0xffffff00 broadcast 192.168.0.255 >>> media: Ethernet autoselect (100baseTX <full-duplex>) >>> status: active >>> carp0: flags=49<UP,LOOPBACK,RUNNING> metric 0 mtu 1500 >>> inet 192.168.0.1 netmask 0xffffff00 >>> carp: MASTER vhid 1 advbase 1 advskew 0 >>> >>> CARP backup: >>> >>> FreeBSD ultra5 8.0-RELEASE FreeBSD 8.0-RELEASE #0: Thu Feb 18 15:19:39 >>> UTC 2010 boris@ultra5:/usr/obj/usr/src/sys/GENERIC.carp sparc64 >>> >>> hme0: flags=8802<BROADCAST,SIMPLEX,MULTICAST> metric 0 mtu 1500 >>> options=b<RXCSUM,TXCSUM,VLAN_MTU> >>> ether 08:00:20:f5:65:d4 >>> media: Ethernet autoselect >>> xl0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> >>> metric 0 >>> mtu 1500 >>> options=9<RXCSUM,VLAN_MTU> >>> ether 00:01:03:2c:06:6d >>> inet 192.168.0.3 netmask 0xffffff00 broadcast 192.168.0.255 >>> media: Ethernet autoselect (100baseTX <full-duplex>) >>> status: active >>> lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384 >>> options=3<RXCSUM,TXCSUM> >>> inet6 fe80::1%lo0 prefixlen 64 scopeid 0x4 >>> inet6 ::1 prefixlen 128 >>> inet 127.0.0.1 netmask 0xff000000 >>> carp0: flags=49<UP,LOOPBACK,RUNNING> metric 0 mtu 1500 >>> inet 192.168.0.1 netmask 0xffffff00 >>> carp: MASTER vhid 1 advbase 1 advskew 100 >>> bridge0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 >>> mtu >>> 1500 >>> ether 3a:e6:09:2d:da:bc >>> id 00:00:00:00:00:00 priority 32768 hellotime 2 fwddelay 15 >>> maxage 20 holdcnt 6 proto rstp maxaddr 100 timeout 1200 >>> root id 00:00:00:00:00:00 priority 32768 ifcost 0 port 0 >>> member: xl0 flags=143<LEARNING,DISCOVER,AUTOEDGE,AUTOPTP> >>> ifmaxaddr 0 port 2 priority 128 path cost 200000 >>> member: hme0 flags=8<SPAN> >>> ifmaxaddr 0 port 1 priority 128 path cost 200000 >>> >>> In summary, I have a basic CARP configuration and, on the backup CARP >>> machine, a bridge with the CARP device's physical interface in it. The >>> purpose of this setup is the ability to monitor traffic passing through >>> that interface using another machine. If the master CARP machine is >>> disconnected from the network, the CARP interface on the backup machine >>> correctly changes to the MASTER state, but does not act on traffic >>> bound >>> for the shared IP address--192.168.0.1. tcpdump shows the traffic >>> coming >>> in on the correct physical interface, but it is never replied to, >>> or, in >>> the case of routing, forwarded. Removing xl0 from the bridge on the >>> backup machine instantly fixes this, and the shared IP address behaves >>> as expected. Adding xl0 back to the bridge while the backup CARP >>> interface is in the MASTER state keeps things running correctly, so the >>> problem is only observed when xl0 is part of the bridge during the CARP >>> transition from BACKUP to MASTER. Thoughts? >>> >> >> I assume the bridge filters out the traffic as it thinks the >> destination is elsewhere (it has previously seen ARPs from the other >> MASTER entering via xl0). It shouldn't do that, but that's a >> different story. You can try to force edge or ptp status on xl0, not >> sure if this does the trick, but it's worth a try. >> >> Regards, >> Max >> > Sure. No go, though, I'm afraid. It's not an operational show-stopper > for me, at least. In the worst case, I can always hack up a PCAP > program to copy the frames around in user space. > > -Boris For the archives, in the off chance that someone else encounters this: http://acm.poly.edu/wiki/Userspace_SPAN_Port -Boris
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