lots of bad checksum on igb
k simon
chio1990 at gmail.com
Thu Apr 17 19:12:15 PDT 2014
And I found lo0 reported bad checksum too.
09:55:02.245185 IP (tos 0x0, ttl 64, id 46728, offset 0, flags [DF],
proto TCP (6), length 40, bad cksum 0 (->8645)!)
127.0.0.1.1300 > 127.0.0.1.25772: Flags [.], cksum 0xdb09
(correct), ack 2032, win 55313, length 0
09:55:02.245217 IP (tos 0x0, ttl 64, id 62953, offset 0, flags [DF],
proto TCP (6), length 48, bad cksum 0 (->46dc)!)
127.0.0.1.25773 > 127.0.0.1.1300: Flags [S], cksum 0xe06d
(correct), seq 1766479763, win 16364, options [mss
16344,nop,nop,sackOK], length 0
09:55:02.245219 IP (tos 0x0, ttl 64, id 26099, offset 0, flags [DF],
proto TCP (6), length 48, bad cksum 0 (->d6d2)!)
127.0.0.1.1300 > 127.0.0.1.25773: Flags [S.], cksum 0xabe4
(correct), seq 1478155337, ack 1766479764, win 16384, options [mss
16344,nop,nop,sackOK], length 0
09:55:02.245222 IP (tos 0x0, ttl 64, id 47494, offset 0, flags [DF],
proto TCP (6), length 40, bad cksum 0 (->8347)!)
127.0.0.1.25773 > 127.0.0.1.1300: Flags [.], cksum 0x72cc
(correct), ack 1, win 57344, length 0
09:55:02.245227 IP (tos 0x0, ttl 64, id 62263, offset 0, flags [DF],
proto TCP (6), length 40, bad cksum 0 (->4996)!)
127.0.0.1.1300 > 127.0.0.1.25773: Flags [.], cksum 0x72cc
(correct), ack 1, win 57344, length 0
09:55:02.245229 IP (tos 0x0, ttl 64, id 32219, offset 0, flags [DF],
proto TCP (6), length 2092, bad cksum 0 (->b6ee)!)
127.0.0.1.25773 > 127.0.0.1.1300: Flags [P.], cksum 0x2c25
(correct), seq 1:2053, ack 1, win 57344, length 2052
09:55:02.245232 IP (tos 0x0, ttl 64, id 18791, offset 0, flags [DF],
proto TCP (6), length 40, bad cksum 0 (->
于 14-4-18 9:38, k simon 写道:
> Hi,Matthew,
> When it report bad checksum, the web pages can not opened. If
> disabled the HW checksum, then it acts normally. I think it's a real
> problem and I would take a bce card try again.
>
> Simon
>
> 于 14-4-18 2:02, Matthew Dillon 写道:
>> Bad checksums reported by tcpdump are not necessarily actually bad. What
>> is happening is that the checksum field is not updated when HW checksums
>> are enabled... the code depends on the HW to tell it if the checksum is
>> bad or not (on receive), and depends on the HW to generate the checksum
>> (on transmit). So the packet in the mbuf which tcpdump is parsing may
>> not have a filled-in checksum field.
>>
>> If you are getting actual communications glitches, e.g. pings not
>> returning, tcp throughput problems, and so forth, then you might have a
>> real problem.
>>
>> -Matt
>>
>>
>> On Thu, Apr 17, 2014 at 2:13 AM, k simon <chio1990 at gmail.com
>> <mailto:chio1990 at gmail.com>> wrote:
>>
>> Hi,List,
>>
>> I have tested haproxy on dfly 3.6.2 and found a lot of bad
>> checksum
>> unless "ifconfig igb0 -txcsum -rxcsum -tso".
>>
>> Simon
>>
>>
>> P.S.
>> igb0 at pci0:1:0:0: class=0x020000 card=0xa04c8086
>> chip=0x10c98086 rev=0x01
>> hdr=0x00
>> vendor = 'Intel Corporation'
>> device = '82576 Gigabit Network Connection'
>> class = network
>> subclass = ethernet
>> igb1 at pci0:1:0:1: class=0x020000 card=0xa04c8086
>> chip=0x10c98086 rev=0x01
>> hdr=0x00
>> vendor = 'Intel Corporation'
>> device = '82576 Gigabit Network Connection'
>> class = network
>> subclass = ethernet
>>
>> # ifconfig igb1
>> igb1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
>> options=5b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,RSS>
>> inet6 fe80::21b:21ff:fea8:f6b5%igb1 prefixlen 64 scopeid 0x2
>> inet 192.168.130.17 netmask 0xfffffe00 broadcast
>> 192.168.131.255
>> ether 00:1b:21:a8:f6:b5
>> media: Ethernet 1000baseT <full-duplex>
>> status: active
>>
>>
>> # tcpdump -vv -n -i igb1
>> tcpdump: listening on igb1, link-type EN10MB (Ethernet), capture size
>> 65535 bytes
>> 00:55:45.864386 IP (tos 0x0, ttl 64, id 24083, offset 0, flags [DF],
>> proto TCP (6), length 670)
>> 192.168.130.50.3002 > 192.168.130.17.15231: Flags [P.], cksum
>> 0x9e22
>> (correct), seq 2769251432:2769252062, ack 3651462828, win 33580,
>> length 630
>> 00:55:45.864403 IP (tos 0x0, ttl 64, id 30506, offset 0, flags [DF],
>> proto TCP (6), length 40, bad cksum 0 (->3e11)!)
>> 192.168.130.17.15231 > 192.168.130.50.3002: Flags [.], cksum
>> 0xcccc
>> (correct), seq 1, ack 630, win 16890, length 0
>> 00:55:45.864435 IP (tos 0x0, ttl 64, id 59651, offset 0, flags [DF],
>> proto TCP (6), length 40, bad cksum 0 (->cc37)!)
>> 192.168.130.17.15231 > 192.168.130.50.3002: Flags [F.], cksum
>> 0xcccb
>> (correct), seq 1, ack 630, win 16890, length 0
>> 00:55:45.864449 IP (tos 0x0, ttl 64, id 29524, offset 0, flags [DF],
>> proto TCP (6), length 40, bad cksum 0 (->41e7)!)
>> 192.168.130.17.15231 > 192.168.130.50.3002: Flags [R.], cksum
>> 0xccc7
>> (correct), seq 2, ack 630, win 16890, length 0
>> 00:55:45.864626 IP (tos 0x0, ttl 64, id 24105, offset 0, flags [DF],
>> proto TCP (6), length 40)
>> 192.168.130.50.3002 > 192.168.130.17.15231: Flags [.], cksum
>> 0x8b99
>> (correct), seq 630, ack 2, win 33580, length 0
>> 00:55:45.864635 IP (tos 0x0, ttl 64, id 17387, offset 0, flags [DF],
>> proto TCP (6), length 40, bad cksum 0 (->7150)!)
>> 192.168.130.17.15231 > 192.168.130.50.3002: Flags [R], cksum
>> 0x22c0
>> (correct), seq 3651462829, win 0, length 0
>> 00:55:46.176994 IP (tos 0x0, ttl 64, id 8022, offset 0, flags [DF],
>> proto TCP (6), length 48, bad cksum 0 (->95ef)!)
>> 192.168.130.17.15232 > 192.168.130.32.3003: Flags [S], cksum
>> 0x75b2
>> (correct), seq 3024833635, win 16384, options [mss
>> 1460,nop,nop,sackOK],
>> length 0
>> 00:55:46.177062 IP (tos 0x0, ttl 64, id 6400, offset 0, flags [DF],
>> proto TCP (6), length 44)
>> 192.168.130.32.3003 > 192.168.130.17.15232: Flags [S.], cksum
>> 0x069f
>> (correct), seq 2868943112, ack 3024833636, win 32768, options [mss
>> 1460], length 0
>> 00:55:46.177074 IP (tos 0x0, ttl 64, id 45321, offset 0, flags [DF],
>> proto TCP (6), length 40, bad cksum 0 (->444)!)
>> 192.168.130.17.15232 > 192.168.130.32.3003: Flags [.], cksum
>> 0x59ec
>> (correct), seq 1, ack 1, win 17520, length 0
>> 00:55:46.177101 IP (tos 0x0, ttl 64, id 21368, offset 0, flags [DF],
>> proto TCP (6), length 80, bad cksum 0 (->61ad)!)
>>
>>
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