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Bug #1836

open

Incorrect TCP checksum show up in tcpdump

Added by robgar1 over 13 years ago. Updated almost 2 years ago.

Status:
New
Priority:
Normal
Assignee:
-
Category:
-
Target version:
Start date:
Due date:
% Done:

0%

Estimated time:

Description

tcpdump -vvni reveals a series of incorrect tcp checksums, all incoming ones
are valid.

    192.168.1.3.1029 > 216.240.41.25.119: Flags [P.], cksum 0xc3ea
(incorrect -> 0xd4a8), seq 2255:2270, ack 2504072, win 1795, options
[nop,nop,TS val 236407 ecr 171513783], length 15
    216.240.41.25.119 > 192.168.1.3.1029: Flags [P.], seq 2504072:2505096,
ack 2270, win 128, options [nop,nop,TS val 171514187 ecr 236407], length
1024
    216.240.41.25.119 > 192.168.1.3.1029: Flags [P.], seq 2505096:2506120,
ack 2270, win 128, options [nop,nop,TS val 171514187 ecr 236407], length
1024
    192.168.1.3.1029 > 216.240.41.25.119: Flags [.], cksum 0xc3db
(incorrect -> 0x8bb1), seq 2270, ack 2506120, win 1763, options [nop,nop,TS
val 236416 ecr 171514187], length 0
    216.240.41.25.119 > 192.168.1.3.1029: Flags [P.], seq 2506120:2506532,
ack 2270, win 128, options [nop,nop,TS val 171514187 ecr 236407], length
412

I have and can confirm that several of the issues appear to be fixed, but
yet there are a few more that arent. Enabling anything that makes large use
of socket, and or IP code is still a problem. In other words I am not sure
the netisr problem is quite yet fixed. I am going to try a couple of tests
and see what happens

RG

Actions #1

Updated by dillon over 13 years ago

:
:tcpdump -vvni reveals a series of incorrect tcp checksums, all incoming ones
:are valid.

These are probably false errors. The packets won't have tcp checksums if hardware checksum offloading is active.
I've made another set of commits, lets see how those fare.

-Matt

Actions #2

Updated by tuxillo almost 2 years ago

  • Description updated (diff)
  • Assignee deleted (0)
Actions #3

Updated by tuxillo almost 2 years ago

  • Subject changed from Crash's and other issues to Incorrect TCP checksum show up in tcpdump
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