On Mon, Mar 26, 2012 at 02:36:31PM +0900, Simon Horman wrote: > On Wed, Mar 21, 2012 at 12:09:09PM -0700, Jesse Gross wrote: > > On Wed, Mar 21, 2012 at 1:52 AM, Simon Horman <ho...@verge.net.au> wrote: > > > Hi Jesse, Hi all, > > > > > > I am currently investigating how STT[1] may be implemented for Open > > > vSwtich. > > > In the course of this it has struck me that a property particular > > > to STT is that it uses the TCP IP protocol number but actually isn't TCP. > > > Which makes me wonder how the receive-side it may be hooked into the Linux > > > kernel. > > > > > > My thought so far is that some modifications may need to be made to > > > tcp_v4_rcv() and/or tcp_v6_rcv() to skip TCP processing of packets > > > for sockets that have been bound by STT. But I was wondering if you > > > have any thoughts on this. > > > > I agree it is an issue. I think what we want is something analogous > > to encap_rcv in the UDP stack, which is used for exactly this purpose > > (for example, the OVS CAPWAP implementation uses it, as do L2TP and > > UDP encapsulated IPsec upstream). It's perhaps somewhat more likely > > to be contentious since with UDP the packets are still processed by > > the UDP stack just without the userspace termination part whereas this > > takes the TCP state machine out of the picture but as least there is > > precedent. > > Agreed, it does seem that there could be some cause for contention there. > > The next thing that I am puzzling over is how to select a source port. > The draft makes reference to using a hash, which seems like a nice idea. > However I am concerned about ensuring that a) the port isn't already in use > and b) nothing else uses it while STT is using it. It seems to me that > an obvious but not necessarily very efficient way to do this would be to > create a sock using sock_create() and bind it using a modified > version if inet_bind() or similar. Do you have any thoughts on this.
Ok, scratch that for the most part. I see that the CAPWAP implementation makes use of sock_create_kern() to create a socket. So it seems that it would be reasonable for an STT implementation to do similar. _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
