Date: Thu, 09 Nov 2006 11:32:17 +0100
From: Olivier MATZ <olivier.matz@6wind.com>
Subject: [users:00265] Re: Computed checksum is wrong
To: users@tahi.org
Message-Id: <455303B1.3070606@6wind.com>
In-Reply-To: <20061109185615.0f8f9023.Yukiyo.Akisada@jp.yokogawa.com>
References: <4542064C.6000302@6wind.com>	<200611090338246.SM02732@037f27dd816a40c>	<4552EF4C.3070907@6wind.com> <20061109185615.0f8f9023.Yukiyo.Akisada@jp.yokogawa.com>
X-Mail-Count: 00265

Hi,

> This text says 'UDP checksum' specifically.
> You may know, RFC 768 says the same.
> 
> This rule is only for UDP, isn't it?
> The value of 0 is valid for protocols other than UDP.

Damn you're right (I read the rfc too quickly...) !! Moreover, I was a
little confused because there is the same bug in wireshark:

matz@glumotte:~/WIRESHARK$ tshark -V -r ~/toto.dump
[...]
Internet Protocol Version 6
    Version: 6
    Traffic class: 0x00
    Flowlabel: 0x00000
    Payload length: 64
    Next header: ICMPv6 (0x3a)
    Hop limit: 64
    Source address: fe80::290:bff:fe04:cced (fe80::290:bff:fe04:cced)
    Destination address: fe80::200:ff:fe00:100 (fe80::200:ff:fe00:100)
Internet Control Message Protocol v6
    Type: 4 (Parameter problem)
    Code: 1 (Next header)
>>> Checksum: 0xffff [correct]      <<<<<<<<<<<<
    Problem pointer: 0x0028
    Internet Protocol Version 6
        Version: 6
        Traffic class: 0x00
        Flowlabel: 0x00000
        Payload length: 16
        Next header: IPv6 destination option (0x3c)
        Hop limit: 64
        Source address: fe80::200:ff:fe00:100 (fe80::200:ff:fe00:100)
        Destination address: fe80::290:bff:fe04:cced
(fe80::290:bff:fe04:cced)
    Destination Option Header
        Next header: AX/4000 Testframe (0xad)
        Length: 0 (8 bytes)
        PadN: 6 bytes

So there's also a wireshark bug ! ... but no bug in TAHI :)

Thanks a lot for your help
Olivier