[ovs-discuss] Need to access packet sequence numbers

[Ben Pfaff]

Please don't drop the mailing list.

OK, you're talking about TCP sequence numbers.  Thanks, that helps.

The code for select groups can't efficiently access the sequence number
for a TCP packet, since that varies on a packet-by-packet basis and
would defeat caching.

On Thu, Jun 02, 2016 at 01:36:19AM +0500, Tooba Ahsen wrote:
> The sequence number is a part of the TCP header of a packet. Each packet of a particular flow would have a sequence number greater than that of the packet that was sent just before it. So it essentially tells you the order/sequence of the packets, in case they reach the receiver in a jumbled order because of delays and such. 
> I basically need to slightly change the select group code in the ofproto-dpif-xlate.c file in the ofproto folder. So I need to access the packet header information so that I can get the sequence number. But Im not sure how to go about doing it. 
> 
> > Date: Wed, 1 Jun 2016 08:09:16 -0700
> > From: blp at ovn.org
> > To: tooba-fire at hotmail.com
> > CC: discuss at openvswitch.org
> > Subject: Re: [ovs-discuss] Need to access packet sequence numbers
> > 
> > On Wed, Jun 01, 2016 at 11:34:52AM +0500, Tooba Ahsen wrote:
> > > I need to alter the code for the select group implementation in ovs. I
> > > need to access the sequence numbers of the packets that come in. I
> > > haven't been successful so far, so can someone tell me how I should go
> > > about doing so?
> > 
> > What's the sequence number of a packet?
>