kern/140712: fxp driver starts with rxcsum on

Jared Mauch jared at
Fri Nov 20 01:50:02 UTC 2009

>Number:         140712
>Category:       kern
>Synopsis:       fxp driver starts with rxcsum on
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Fri Nov 20 01:50:01 UTC 2009
>Originator:     Jared Mauch
>Release:        FreeBSD 8.0-RC3 i386
FreeBSD 8.0-RC3 FreeBSD 8.0-RC3 #0: Tue Nov 10 07:50:36 UTC 2009     root at  i386

	Upon upgrading from 7.0-release to 8.0-RC3 the fxp0 interface came with rxcsum enabled, eg:

# ifconfig fxp0
fxp0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
	ether 00:20:fc:1e:dd:00
	inet netmask 0xfffffffc broadcast
	inet6 fe80::220:fcff:fe1e:dd00%fxp0 prefixlen 64 scopeid 0x1 
	media: Ethernet 100baseTX <full-duplex>
	status: active
# sysctl -a | grep fxp
dev.fxp.0.%desc: Intel 82559ER Embedded 10/100 Ethernet
dev.fxp.0.%driver: fxp
dev.fxp.0.%location: slot=4 function=0
dev.fxp.0.%pnpinfo: vendor=0x8086 device=0x1209 subvendor=0x102b subdevice=0x6000 class=0x020000
dev.fxp.0.%parent: pci3
dev.fxp.0.int_delay: 1000
dev.fxp.0.bundle_max: 6
dev.fxp.0.rnr: 0
dev.fxp.0.noflow: 1

	This caused truncated IP packets/messages to be received by the kernel resulting in the machine being unreachable.

# tcpdump -n -i fxp0 -c 3 -s0
fxp0: promiscuous mode enabled
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on fxp0, link-type EN10MB (Ethernet), capture size 65535 bytes
01:52:48.166315 IP truncated-ip - 2 bytes missing! > ICMP echo request, id 33313, seq 5139, length 64
01:52:49.166155 IP truncated-ip - 2 bytes missing! > ICMP echo request, id 33313, seq 5140, length 64
01:52:50.166276 fIP truncated-ip x- 2 bytes missinpg! > ICMP echo req uest, id 33313, pseq 5141, lengthr 64
3 packets coaptured
3 packemts received by fiilter
0 packetss dropped by kerncel
uous mode disabled


	Reboot the system with this hardware installed/used.

	ifconfig fxp0 -rxcsum


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