kern/111384: msk hw checksum problem
Harald Schmalzbauer
harry at omnisec.de
Sun Apr 8 17:40:03 UTC 2007
>Number: 111384
>Category: kern
>Synopsis: msk hw checksum problem
>Confidential: no
>Severity: serious
>Priority: high
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Sun Apr 08 17:40:02 GMT 2007
>Closed-Date:
>Last-Modified:
>Originator: Harald Schmalzbauer
>Release: FreeBSD 7.0-CURRENT i386
>Organization:
>Environment:
System: FreeBSD titan.flintsbach.schmalzbauer.de 7.0-CURRENT FreeBSD 7.0-CURRENT #4: Sun Apr 8 16:10:26 CEST 2007 root at titan.flintsbach.schmalzbauer.de:/usr/obj/usr/src/sys/TITAN i386
src from 5. April
>Description:
By default msk runs with:
options=19a<TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,TSO4>
This leads to "TCP CHECKSUM INCORRECT" messages captured with wireshark.
The problem was that I could not connect to some websites (www.freshports.org)
My site sent TCP ZeroWindowProbe - I don't know why!!!
After disabling txcsum (ifconfig msk0 -txcsum) www.freshports.org communication is ok.
>How-To-Repeat:
Under 7.0-current use any web browser and try to connect to http://www.freshports.org
You won't get a connection.
Now do 'ifconfig msk0 -txcsum' and reconnect.
You'll see what you expected.
Here's what wireshark captured with txcsum on (failing connection):
No. Time Source Destination Protocol Info
1 0.000000 172.21.1.0 64.147.113.42 TCP 55771 > http [SYN] Seq=0 [TCP CHECKSUM INCORRECT] Len=0 MSS=1460 WS=8 TSV=2163927 TSER=0
Frame 1 (74 bytes on wire, 74 bytes captured)
Ethernet II, Src: Giga-Byt_80:cd:51 (00:16:e6:80:cd:51), Dst: Olicom_c0:33:71 (00:00:24:c0:33:71)
Internet Protocol, Src: 172.21.1.0 (172.21.1.0), Dst: 64.147.113.42 (64.147.113.42)
Transmission Control Protocol, Src Port: 55771 (55771), Dst Port: http (80), Seq: 0, Len: 0
No. Time Source Destination Protocol Info
2 0.099367 64.147.113.42 172.21.1.0 TCP http > 55771 [SYN, ACK] Seq=0 Ack=1 Win=0 Len=0 MSS=1452
Frame 2 (60 bytes on wire, 60 bytes captured)
Ethernet II, Src: Olicom_c0:33:71 (00:00:24:c0:33:71), Dst: Giga-Byt_80:cd:51 (00:16:e6:80:cd:51)
Internet Protocol, Src: 64.147.113.42 (64.147.113.42), Dst: 172.21.1.0 (172.21.1.0)
Transmission Control Protocol, Src Port: http (80), Dst Port: 55771 (55771), Seq: 0, Ack: 1, Len: 0
No. Time Source Destination Protocol Info
3 0.099431 172.21.1.0 64.147.113.42 TCP 55771 > http [ACK] Seq=1 Ack=1 Win=65535 [TCP CHECKSUM INCORRECT] Len=0
Frame 3 (54 bytes on wire, 54 bytes captured)
Ethernet II, Src: Giga-Byt_80:cd:51 (00:16:e6:80:cd:51), Dst: Olicom_c0:33:71 (00:00:24:c0:33:71)
Internet Protocol, Src: 172.21.1.0 (172.21.1.0), Dst: 64.147.113.42 (64.147.113.42)
Transmission Control Protocol, Src Port: 55771 (55771), Dst Port: http (80), Seq: 1, Ack: 1, Len: 0
No. Time Source Destination Protocol Info
4 5.281304 172.21.1.0 64.147.113.42 TCP [TCP ZeroWindowProbe] 55771 > http [ACK] Seq=1 Ack=1 Win=65535 [TCP CHECKSUM INCORRECT] Len=1
Frame 4 (55 bytes on wire, 55 bytes captured)
Ethernet II, Src: Giga-Byt_80:cd:51 (00:16:e6:80:cd:51), Dst: Olicom_c0:33:71 (00:00:24:c0:33:71)
Internet Protocol, Src: 172.21.1.0 (172.21.1.0), Dst: 64.147.113.42 (64.147.113.42)
Transmission Control Protocol, Src Port: 55771 (55771), Dst Port: http (80), Seq: 1, Ack: 1, Len: 1
No. Time Source Destination Protocol Info
5 10.445927 172.21.1.0 64.147.113.42 TCP [TCP ZeroWindowProbe] 55771 > http [ACK] Seq=1 Ack=1 Win=65535 [TCP CHECKSUM INCORRECT] Len=1
Frame 5 (55 bytes on wire, 55 bytes captured)
Ethernet II, Src: Giga-Byt_80:cd:51 (00:16:e6:80:cd:51), Dst: Olicom_c0:33:71 (00:00:24:c0:33:71)
Internet Protocol, Src: 172.21.1.0 (172.21.1.0), Dst: 64.147.113.42 (64.147.113.42)
Transmission Control Protocol, Src Port: 55771 (55771), Dst Port: http (80), Seq: 1, Ack: 1, Len: 1
No. Time Source Destination Protocol Info
6 11.600999 172.21.1.0 64.147.113.42 HTTP Continuation or non-HTTP traffic
Frame 6 (55 bytes on wire, 55 bytes captured)
Ethernet II, Src: Giga-Byt_80:cd:51 (00:16:e6:80:cd:51), Dst: Olicom_c0:33:71 (00:00:24:c0:33:71)
Internet Protocol, Src: 172.21.1.0 (172.21.1.0), Dst: 64.147.113.42 (64.147.113.42)
Transmission Control Protocol, Src Port: 60906 (60906), Dst Port: http (80), Seq: 0, Ack: 0, Len: 1
Hypertext Transfer Protocol
No. Time Source Destination Protocol Info
7 15.635975 172.21.1.0 64.147.113.42 TCP [TCP ZeroWindowProbe] 55771 > http [ACK] Seq=1 Ack=1 Win=65535 [TCP CHECKSUM INCORRECT] Len=1
Frame 7 (55 bytes on wire, 55 bytes captured)
Ethernet II, Src: Giga-Byt_80:cd:51 (00:16:e6:80:cd:51), Dst: Olicom_c0:33:71 (00:00:24:c0:33:71)
Internet Protocol, Src: 172.21.1.0 (172.21.1.0), Dst: 64.147.113.42 (64.147.113.42)
Transmission Control Protocol, Src Port: 55771 (55771), Dst Port: http (80), Seq: 1, Ack: 1, Len: 1
No. Time Source Destination Protocol Info
8 22.410580 172.21.1.0 64.147.113.42 TCP [TCP ZeroWindowProbe] 55771 > http [ACK] Seq=1 Ack=1 Win=65535 [TCP CHECKSUM INCORRECT] Len=1
Frame 8 (55 bytes on wire, 55 bytes captured)
Ethernet II, Src: Giga-Byt_80:cd:51 (00:16:e6:80:cd:51), Dst: Olicom_c0:33:71 (00:00:24:c0:33:71)
Internet Protocol, Src: 172.21.1.0 (172.21.1.0), Dst: 64.147.113.42 (64.147.113.42)
Transmission Control Protocol, Src Port: 55771 (55771), Dst Port: http (80), Seq: 1, Ack: 1, Len: 1
No. Time Source Destination Protocol Info
9 35.797198 172.21.1.0 64.147.113.42 TCP [TCP ZeroWindowProbe] 55771 > http [ACK] Seq=1 Ack=1 Win=65535 [TCP CHECKSUM INCORRECT] Len=1
Frame 9 (55 bytes on wire, 55 bytes captured)
Ethernet II, Src: Giga-Byt_80:cd:51 (00:16:e6:80:cd:51), Dst: Olicom_c0:33:71 (00:00:24:c0:33:71)
Internet Protocol, Src: 172.21.1.0 (172.21.1.0), Dst: 64.147.113.42 (64.147.113.42)
Transmission Control Protocol, Src Port: 55771 (55771), Dst Port: http (80), Seq: 1, Ack: 1, Len: 1
No. Time Source Destination Protocol Info
10 41.158461 172.21.1.0 64.147.113.42 HTTP Continuation or non-HTTP traffic
Frame 10 (55 bytes on wire, 55 bytes captured)
Ethernet II, Src: Giga-Byt_80:cd:51 (00:16:e6:80:cd:51), Dst: Olicom_c0:33:71 (00:00:24:c0:33:71)
Internet Protocol, Src: 172.21.1.0 (172.21.1.0), Dst: 64.147.113.42 (64.147.113.42)
Transmission Control Protocol, Src Port: 51037 (51037), Dst Port: http (80), Seq: 0, Ack: 0, Len: 1
Hypertext Transfer Protocol
No. Time Source Destination Protocol Info
11 62.348550 172.21.1.0 64.147.113.42 TCP [TCP ZeroWindowProbe] 55771 > http [ACK] Seq=1 Ack=1 Win=65535 [TCP CHECKSUM INCORRECT] Len=1
Frame 11 (55 bytes on wire, 55 bytes captured)
Ethernet II, Src: Giga-Byt_80:cd:51 (00:16:e6:80:cd:51), Dst: Olicom_c0:33:71 (00:00:24:c0:33:71)
Internet Protocol, Src: 172.21.1.0 (172.21.1.0), Dst: 64.147.113.42 (64.147.113.42)
Transmission Control Protocol, Src Port: 55771 (55771), Dst Port: http (80), Seq: 1, Ack: 1, Len: 1
No. Time Source Destination Protocol Info
12 73.955802 172.21.1.0 64.147.113.42 TCP [TCP Keep-Alive] 60906 > http [ACK] Seq=0 Ack=0 Win=65535 Len=1
Frame 12 (55 bytes on wire, 55 bytes captured)
Ethernet II, Src: Giga-Byt_80:cd:51 (00:16:e6:80:cd:51), Dst: Olicom_c0:33:71 (00:00:24:c0:33:71)
Internet Protocol, Src: 172.21.1.0 (172.21.1.0), Dst: 64.147.113.42 (64.147.113.42)
Transmission Control Protocol, Src Port: 60906 (60906), Dst Port: http (80), Seq: 0, Ack: 0, Len: 1
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
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