On 22/04/14 - 10:00:43, Rishi Madhan wrote: > >You basically have to reimplement a full TCP-stack at the driver as each > >TCP-subflow has to behave as regular TCP (3-way handshake, > >retransmissions,...) > Can it be done like the usb modem driver ? Like adding the NCM or QMI or > RNDIS header on the data field . > Rather than changing the entire tcp header in the driver level .
I don't know exactly what the usb modem driver does, but for MPTCP it is much more complex than just adding some bits to a segment. > In case of mptcp only the option field has to be changed . And the TCP/IP-header as you want to send your traffic via different paths. > And instead of sending the mptcp flags (such as mp_cap ,mp_join) > inside option . Can it be done on the data ? Then, this would be a whole new protocol, no more MPTCP. That's a different story, and the idea of putting everything inside the data instead of the TCP-option space has been widely discussed at the IETF, but got rejected because of deadlock-issues with such an approach. > The main reason why i am tryin to implement in this way is the effect of the > MIDDLEBOX . What do you mean by the effect of the middlebox? Btw., I'm not sure if lkml is the right place to discuss this. Maybe move the discussion to mptcp-dev. Cheers, Christoph > and also that server need not > rebuild kernel (most of them dont want to also) and can dynamically > load/unload driver on need basis . > > Regards, > Madhan > > On Tue, Apr 22, 2014 at 1:44 PM, Christoph Paasch > <christoph.paa...@uclouvain.be<mailto:christoph.paa...@uclouvain.be>> wrote: > Hello, > > On 22/04/14 - 05:27:55, Madhan wrote: > > hi , > > Is it possible to update the option field of the tcp header dynamically by > > the driver rather than the change in tcp/ip stack . > > i.e Can i add a driver to implement mptcp rather than building entire > > kernel again ? > > in principle it seems possible to do this at a driver-level. Alcatel-Lucent > implemented something similar using netfilter-hooks: > https://open-innovation.alcatel-lucent.com/projects/mptcp-proxy > > Regular TCP was running on top, and the netfilter hooks allowed to > rewrite the TCP/IP header. > > > However, I think that doing it that way will be huge implementation effort > (considering that there exists already an open-source implementation at > multipath-tcp.org<http://multipath-tcp.org>) and it might be hard to achieve > good performance and make it > scale properly. > > You basically have to reimplement a full TCP-stack at the driver as each > TCP-subflow has to behave as regular TCP (3-way handshake, > retransmissions,...) > > > Cheers, > Christoph > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to > majord...@vger.kernel.org<mailto:majord...@vger.kernel.org> > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
