Wireshark-users: Re: [Wireshark-users] IP Data checksum

From: Sada Mita <sada_mita@xxxxxxxxx>
Date: Tue, 3 Oct 2006 00:45:34 +0100 (BST)
Hello,
 
I'm running 0.99.4-SVN-19188.(Running 0.99.3, the result is the same.)
Does it follow the IPv6 VRRP checksum spec?
I still see the checksum incorrect on IPv6 VRRP packet from my DUT.
Could someone check it ?
I am having a trouble to isolate if my DUT has a problem or Wireshark has a problem.
 
 
5.3.7 Checksum

   The checksum field is used to detect data corruption in the VRRP
   message.

   The checksum is the 16-bit one's complement of the one's complement
   sum of the entire VRRP message starting with the version field and a
   "pseudo-header" as defined in section 8.1 of RFC2460 [IPv6].  The
   next header field in the "pseudo-header" should be set to 112
   (decimal) for VRRP.  For computing the checksum, the checksum field
   is set to zero.  See RFC1071 for more detail [CKSM].
 
Cut&paste from test2pcap.c
 
static hdr_ip_t HDR_IP = {0x45, 0, 0, 0x3412, 0, 0, 0xff, 0, 0, 0x01010101, 0x02020202};
 
static struct {   /* pseudo header for checksum calculation */
 guint32 src_addr;
 guint32 dest_addr;
 guint8  zero;
 guint8  protocol;
 guint16 length;
} pseudoh;
 
Thanks
Sam
 
 
 
 
 
 
 
 
 
 
Message: 6
Date: Tue, 22 Aug 2006 12:34:34 +0200
From: Joerg Mayer <jmayer@xxxxxxxxx>
Subject: Re: [Wireshark-users] IP Data checksum
To: Community support list for Wireshark
<wireshark-users@xxxxxxxxxxxxx>
Message-ID: <20060822103434.GB5709@xxxxxxxxxxxxxxxxxxxxxxxxx>
Content-Type: text/plain; charset=us-ascii

On Mon, Aug 21, 2006 at 07:04:15PM -0700, Guy Harris wrote:
> Try the current version of Wireshark; there might have been a bug in 
> earlier versions.  If there's still a bug in the current version, ask 
> again.

A bug was recently fixed in wireshark svn. So either get a snapshot
build or wait for wireshark 0.99.3 which should be out this week.

ciao
     Joerg