UDP checksum calculation correct?

[midi...@googlemail.com]

Is the UDP checksum calculated correctly by ostinato?

If I'm not wrong the UDP checksum should be calculated as described in RFC768.

In there it's said that a calculated checksum of 0x0000 should be replaced by 0xFFFF. That doesn't seem to happen in ostinato.

I have attached a file with an ostinato stream for which a checksum of 0x0000 is calculated.

Best regards Markus

[Srivats P]

Markus,

You are right - Ostinato is not replacing 0 with 0xFFFF as it should
according to the RFC. UDP checksum 0 indicates "no checksum", so
receiver will not do a checksum verification which is not the
intention here.

Please file a bug and I'll fix it.

Note: It looks like this replacing 0 with 0xFFFF business should be
done only for UDP and not for TCP?

Srivats

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[midi...@googlemail.com]

I do not have a GitHub account, that's why I have reported that here.

I think it is correct that this only applies to the UDP checksum and not to the IP header checksum, but I'm not a 100% sure.

Markus

[Srivats P]

Ok. I filed https://github.com/pstavirs/ostinato/issues/160

Thanks for reporting the issue.

Srivats

[Srivats P]

I've pushed the fix to the repository.

Srivats

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[midi...@googlemail.com]

Great. I'm glad that I could help.

Markus

Am Mittwoch, 7. Oktober 2015 06:39:40 UTC+2 schrieb midi...@googlemail.com: