lots of bad checksum on igb

[k simon]

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)!)
>
>