2.5.65 ipv6 TCP checksum errors (capture attached)

2.5.65 ipv6 TCP checksum errors (capture attached)

Post by bert huber » Thu, 20 Mar 2003 14:50:11



Interestingly, the initial ssh connection worked, the second one failed.
Subsequent attempts fail too.

This all over ipv6:

hubert# tcpdump -r file -v -v
29.09 snapcount.33408 > hubert.ssh: S [tcp sum ok] 2737328594:2737328594(0) win 5760 <mss 1440,sackOK,timestamp 10690463 0,nop,wscale 0> (len 40, hlim 64)
29.09 hubert.ssh > snapcount.33408: S [tcp sum ok] 2399386333:2399386333(0) ack 2737328595 win 5712 <mss 1440,sackOK,timestamp 10865690 10690463,nop,wscale 0> (len 40, hlim 64)
29.09 snapcount.33408 > hubert.ssh: . [tcp sum ok] 1:1(0) ack 1 win 5760 <nop,nop,timestamp 10690464 10865690> (len 32, hlim 64)
29.10 hubert.ssh > snapcount.33408: P [bad tcp cksum 4f2!] 1:41(40) ack 1 win 5712 <nop,nop,timestamp 10865695 10690464> (len 72, hlim 64)
29.30 hubert.ssh > snapcount.33408: P [bad tcp cksum 3bf1!] 1:41(40) ack 1 win 5712 <nop,nop,timestamp 10865896 10690464> (len 72, hlim 64)
29.83 hubert.ssh > snapcount.33408: P [bad tcp cksum 23ef!] 1:41(40) ack 1 win 5712 <nop,nop,timestamp 10866432 10690464> (len 72, hlim 64)
30.86 hubert.ssh > snapcount.33408: P [bad tcp cksum 23eb!] 1:41(40) ack 1 win 5712 <nop,nop,timestamp 10867456 10690464> (len 72, hlim 64)

Both hosts run 2.5.65. hubert.ipv6.ds9a.nl (publically routable, so you
can try to ssh to me as long as I'm not asleep, the machine is next to my
bed) is a pentium pro 200. Kernel was make mrpropered before compiling,
* kernel.

Capture attached.

Regards,

bert

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http://www.veryComputer.com/           Linux Advanced Routing & Traffic Control HOWTO
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  bad-csum
1K Download
 
 
 

2.5.65 ipv6 TCP checksum errors (capture attached)

Post by bert huber » Fri, 21 Mar 2003 17:30:15



> Interestingly, the initial ssh connection worked, the second one failed.
> Subsequent attempts fail too.

I've since let loose the excellent ethereal on this and found out:

Quote:> hubert# tcpdump -r file -v -v
> 29.09 snapcount.33408 > hubert.ssh: S [tcp sum ok] 2737328594:2737328594(0) win 5760 <mss 1440,sackOK,timestamp 10690463 0,nop,wscale 0> (len 40, hlim 64)
> 29.09 hubert.ssh > snapcount.33408: S [tcp sum ok] 2399386333:2399386333(0) ack 2737328595 win 5712 <mss 1440,sackOK,timestamp 10865690 10690463,nop,wscale 0> (len 40, hlim 64)
> 29.09 snapcount.33408 > hubert.ssh: . [tcp sum ok] 1:1(0) ack 1 win 5760 <nop,nop,timestamp 10690464 10865690> (len 32, hlim 64)

So far so good.

Quote:> 29.10 hubert.ssh > snapcount.33408: P [bad tcp cksum 4f2!] 1:41(40) ack 1 win 5712 <nop,nop,timestamp 10865695 10690464> (len 72, hlim 64)
> 29.30 hubert.ssh > snapcount.33408: P [bad tcp cksum 3bf1!] 1:41(40) ack 1 win 5712 <nop,nop,timestamp 10865896 10690464> (len 72, hlim 64)
> 29.83 hubert.ssh > snapcount.33408: P [bad tcp cksum 23ef!] 1:41(40) ack 1 win 5712 <nop,nop,timestamp 10866432 10690464> (len 72, hlim 64)
> 30.86 hubert.ssh > snapcount.33408: P [bad tcp cksum 23eb!] 1:41(40) ack 1 win 5712 <nop,nop,timestamp 10867456 10690464> (len 72, hlim 64)

These packets all have an identical csum of 0x680d, it is not being updated.
So, the SYN/SYNACK/ACK stuff went fine, the initial data however has a wrong
checksum.

For completeness, I've attached the capture again.

Regards,

bert

--
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http://lartc.org           Linux Advanced Routing & Traffic Control HOWTO
http://netherlabs.nl                         Consulting

  bad-csum
1K Download

 
 
 

1. ide kernel panic: 2.5.64-ac3 2.5.65-ac1 2.5.65-mm4

AMD K6/2 with VIA chipset has this panic at boot:

Kernel panic: ide: default attach failed

Panic on 2.5.64-ac3, 2.5.65-ac[13], 2.5.65-mm4, 2.5.65-bk4.

No panic on 2.5.61-ac1, 2.5.65-mm3, 2.5.65, 2.4.21-pre5, 2.4.21-pre5-ac3.

No modules.

egrep '^C.*IDE|^C.*VIA' /usr/src/linux-2.5.65-ac1/.config
CONFIG_IDE=y
CONFIG_BLK_DEV_IDE=y
CONFIG_BLK_DEV_IDEDISK=y
CONFIG_IDEDISK_MULTI_MODE=y
CONFIG_BLK_DEV_IDECD=y
CONFIG_BLK_DEV_IDEPCI=y
CONFIG_BLK_DEV_IDEDMA_PCI=y
CONFIG_IDEDMA_PCI_AUTO=y
CONFIG_BLK_DEV_IDEDMA=y
CONFIG_BLK_DEV_VIA82CXXX=y
CONFIG_IDEDMA_AUTO=y
CONFIG_BLK_DEV_IDE_MODES=y

Boot message on 2.5.65-ac1:

Uniform Multi-Platform E-IDE driver Revision: 7.00alpha2
ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx
VP_IDE: IDE controller at PCI slot 00:07.1
VP_IDE: chipset revision 6
VP_IDE: not 100% native mode: will probe irqs later
VP_IDE: VIA vt82c586b (rev 47) IDE UDMA33 controller on pci00:07.1
    ide0: BM-DMA at 0xe000-0xe007, BIOS settings: hda:DMA, hdb:DMA
    ide1: BM-DMA at 0xe008-0xe00f, BIOS settings: hdc:DMA, hdd:DMA
hda: Maxtor 51536U3, ATA DISK drive
hdb: ATAPI CDROM, ATAPI CD/DVD-ROM drive
ide0 at 0x1f0-0x1f7,0x3f6 on irq 14
hdc: Maxtor 52049U4, ATA DISK drive
ide1 at 0x170-0x177,0x376 on irq 15
hda: host protected area => 1
hda: 30015216 sectors (15368 MB) w/2048KiB Cache, CHS=29777/16/63, UDMA(33)
 hda: [PTBL] [1868/255/63] hda1 hda2 hda3
hdc: host protected area => 1
hdc: 40020624 sectors (20491 MB) w/2048KiB Cache, CHS=39703/16/63, UDMA(33)
 hdc: hdc1 hdc2 hdc3
ide-disk: hdc: Failed to register the driver with ide.c
ide-default: hdc: Failed to register the driver with ide.c
Kernel panic: ide: default attach failed

lspci -vvv for IDE interface

IDE interface: VIA Technologies, Inc. Bus Master IDE (rev 06) (prog-if 8a [Master SecP PriP])
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
Status: Cap- 66Mhz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR-
Latency: 64
Region 4: I/O ports at e000 [size=16]

lspci
00:00.0 Host bridge: VIA Technologies, Inc. VT82C598 [Apollo MVP3] (rev 04)
00:01.0 PCI bridge: VIA Technologies, Inc. VT82C598/694x [Apollo MVP3/Pro133x AGP]
00:07.0 ISA bridge: VIA Technologies, Inc. VT82C586/A/B PCI-to-ISA [Apollo VP] (rev 47)
00:07.1 IDE interface: VIA Technologies, Inc. Bus Master IDE (rev 06)
00:07.3 Host bridge: VIA Technologies, Inc. VT82C586B ACPI (rev 10)
00:13.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8139/8139C (rev 10)
01:00.0 VGA compatible controller: nVidia Corporation NV6 [Vanta] (rev 15)

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2. Another fgrep query

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