Re: ipq_get_packet receives proper TCP and IP headers but the rest of payload is junk

[Patrick McHardy <kaber@trash.net>]

Nick Landry wrote:
> Thanks, I checked that but the issue is that I am sending the exact
> same GET request (Accept-Encoding is the same as well) for when the
> message passes through any of the machines.  The read from ip_queue
> for one machine is headers + ascii which is what I'd expect.  The
> other machine outputs headers + junk.
> 
> Here's a hex dump for the machine that isn't working (payload length
> is 1500 bytes but I'll only print a small part):
> 
> -->  45 00 05 78 02 37 40 00 42 06 18 5b 0a b3 00 0c
> -->  0a 2b 04 05 c5 3a 00 50 26 a2 08 34 a8 d5 7c f7
> -->  80 10 4f b0 de f3 00 00 08 0a e4 eb 14 02 d5 6e
> -->  e4 1c 00 00 08 00 01 00 06 00 0f f7 b5 9b 00 00
> -->  00 00 00 00 00 00 00 00 30 00 00 00 00 00 00 00
> -->  45 00 00 30 bf 76 40 00 7c 06 d4 35 0a b1 2c 0f
> -->  0a b3 29 a9 13 4b 01 bd 29 7a 9e 75 00 00 00 00
> -->  70 02 40 00 fb 0b 00 00 02 04 05 b4 01 01 04 02
> -->  01 01 04 02 00 15 17 29 49 62 08 00 45 08 00 34
> -->  64 1b 40 00 40 06 be 0d 0a 2a 02 21 0a 2a 02 1f
> -->  80 03 bb 06 8c bc 41 58 79 bb 93 af 80 10 80 00
> -->  62 96 00 00 01 01 08 0a 00 2d 7d cc 19 d0 cd 3f
> -->  b1 18 40 00 7e 00 40 00 00 00 00 00 82 00 16 00
> -->  38 18 04 00 7e 00 40 00 00 00 08 00 00 00 00 00
> -->  01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> -->  00 00 00 00 00 00 00 00 b1 18 40 00 54 00 40 00
> -->  01 00 01 00 80 00 01 00 01 00 01 00 01 00 14 00
> -->  3b 03 05 00 7e 00 40 00 00 00 00 00 00 00 00 00
> -->  82 00 16 00 3e 00 07 00 b1 18 40 00 73 00 40 00
> -->  7e 00 40 00 00 00 00 00 00 00 00 00 82 00 16 00
> [....]
> 
> And it just goes on like that.  The NULLs are what leads me to believe
> that I'm getting back data that the kernel copied from the wrong part
> of memory (that and the output is different every time I run it, even
> though it's the same GET message).


Possibly related to ip_queue TSO handling bugs in old kernels. Are
you using TSO?