On Thu, Nov 3, 2011 at 10:44 AM, Hefty, Sean <sean.he...@intel.com> wrote: >> Is it possible to send/recv datagrams with no previous connection >> similar to UDP sendto/recvfrom? UD examples I've seen are connection >> oriented and listen/connect/accept, establishing a connection prior to >> conversing. > > To send a datagram, you need the QP number, qkey, and addressing information > of the remote side. The UD examples that use listen/connect are still > connectionless, but require the use of those calls mainly to resolve the > remote QP number. > > We may be able to add a sendto operation to the rdma_cm, but it would need to > resolve the QPN and ibv_ah under the API for the first send to each > destination. > >> It appears that in order to do what I want, I need an ibv_ah to put in >> the send wr. But how do I create one of these from an IP address/port >> without doing an rdma_connect and waiting for >> RDMA_CM_EVENT_ESTABLISHED? > > You still need to convert the IP address into an RDMA address (i.e. LID) and > discover the QPN.
Are there calls in rdma_cm that allow me to do this? For the life of me I can't figure out how, for instance, I would write an app that has a single QP that recieves UD datagrams from anyone. How do potential clients find the QP number, qkey and ah without using listen/accept which will create a brand new QP every time? -K -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
