[ovs-discuss] add/sub a constant value to tcp sequence number and ack number in ovs

Seyyed Hesamoddin Ghasemi s.hesam.ghasemi at gmail.com
Sat Sep 12 19:10:17 UTC 2015


Tnx Gal and Justin,
But  why they don't provide visibility of sequence number and ack number to
the OVS? If it could be possible, the SDN controller can establish TCP
connections, and when get the http packet it can set a rule for that flow
in the OVS. this rule can contain action fileds i.e. add/sub a constant
value to sequence number and add/sub another constant value to the ack
number (like proxy).In this case the rest of the packets of this session
forwarded through OVS. By this feature we can implement content-aware load
balancer.

On Sat, Sep 12, 2015 at 10:39 PM, Justin Pettit <jpettit at nicira.com> wrote:

>
> > On Sep 12, 2015, at 6:21 AM, Seyyed Hesamoddin Ghasemi <
> s.hesam.ghasemi at gmail.com> wrote:
> >
> > Why not? As I know OVS have access to all header fields in layer 2 to
> layer 4!
>
> We don't provide the ability to match on sequence numbers because they're
> not generally very useful for forwarding decisions, and it would have a
> horrible impact on performance.
>
> > How can I Implement a simple proxy using OVS? I mean, how can get packet
> from a source node and send it to a destination node in a transparent
> manner?
> >
> > I need to get first 4 packet of a tcp session in the controller (as a
> proxy) and then forward the rest of packets using OVS without intervention
> of the controller and with keep current tcp session. How can I do that?
>
> As Gal mentioned, I think the way to do it is by building on the conntrack
> work.  Some of the developers at VMware are starting to think about how to
> add that support to OVS.  Adding load-balancing will probably be built on
> top of NAT support, which will be built on conntrack.  If you're interested
> in doing this work yourself, I'd recommend looking into that, too.
>
> --Justin
>
>
>
>


-- 
Seyyed Hesamoddin Ghasemi
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