NAME | SYNOPSIS | ARGUMENTS | DESCRIPTION | RETURN VALUE | NOTES | CONNECTION PROPERTIES | INFINIBAND SPECIFIC | SEE ALSO | COLOPHON

RDMA_ACCEPT(3)          Librdmacm Programmer's Manual         RDMA_ACCEPT(3)

NAME         top

       rdma_accept - Called to accept a connection request.

SYNOPSIS         top

       #include <rdma/rdma_cma.h>

       int rdma_accept (struct rdma_cm_id *id, struct rdma_conn_param
       *conn_param);

ARGUMENTS         top

       id          Connection identifier associated with the request.

       conn_param  Information needed to establish the connection.  See
                   CONNECTION PROPERTIES below for details.

DESCRIPTION         top

       Called from the listening side to accept a connection or datagram
       service lookup request.

RETURN VALUE         top

       Returns 0 on success, or -1 on error.  If an error occurs, errno will
       be set to indicate the failure reason.

NOTES         top

       Unlike the socket accept routine, rdma_accept is not called on a
       listening rdma_cm_id.  Instead, after calling rdma_listen, the user
       waits for an RDMA_CM_EVENT_CONNECT_REQUEST event to occur.
       Connection request events give the user a newly created rdma_cm_id,
       similar to a new socket, but the rdma_cm_id is bound to a specific
       RDMA device.  rdma_accept is called on the new rdma_cm_id.

CONNECTION PROPERTIES         top

       The following properties are used to configure the communication and
       specified by the conn_param parameter when accepting a connection or
       datagram communication request.  Users should use the rdma_conn_param
       values reported in the connection request event to determine
       appropriate values for these fields when accepting.  Users may
       reference the rdma_conn_param structure in the connection event
       directly, or can reference their own structure.  If the
       rdma_conn_param structure from an event is referenced, the event must
       not be acked until after this call returns.

       If the conn_param parameter is NULL, the values reported in the
       connection request event are used, adjusted down based on local
       hardware restrictions.

       private_data
              References a user-controlled data buffer.  The contents of the
              buffer are copied and transparently passed to the remote side
              as part of the communication request.  May be NULL if
              private_data is not required.

       private_data_len
              Specifies the size of the user-controlled data buffer.  Note
              that the actual amount of data transferred to the remote side
              is transport dependent and may be larger than that requested.

       responder_resources
              The maximum number of outstanding RDMA read and atomic
              operations that the local side will accept from the remote
              side.  Applies only to RDMA_PS_TCP.  This value must be less
              than or equal to the local RDMA device attribute
              max_qp_rd_atom, but preferably greater than or equal to the
              responder_resources value reported in the connect request
              event.

       initiator_depth
              The maximum number of outstanding RDMA read and atomic
              operations that the local side will have to the remote side.
              Applies only to RDMA_PS_TCP.  This value must be less than or
              equal to the local RDMA device attribute max_qp_init_rd_atom
              and the initiator_depth value reported in the connect request
              event.

       flow_control
              Specifies if hardware flow control is available.  This value
              is exchanged with the remote peer and is not used to configure
              the QP.  Applies only to RDMA_PS_TCP.

       retry_count
              This value is ignored.

       rnr_retry_count
              The maximum number of times that a send operation from the
              remote peer should be retried on a connection after receiving
              a receiver not ready (RNR) error.  RNR errors are generated
              when a send request arrives before a buffer has been posted to
              receive the incoming data.  Applies only to RDMA_PS_TCP.

       srq    Specifies if the QP associated with the connection is using a
              shared receive queue.  This field is ignored by the library if
              a QP has been created on the rdma_cm_id.  Applies only to
              RDMA_PS_TCP.

       qp_num Specifies the QP number associated with the connection.  This
              field is ignored by the library if a QP has been created on
              the rdma_cm_id.

INFINIBAND SPECIFIC         top

       In addition to the connection properties defined above, InfiniBand
       QPs are configured with minimum RNR NAK timer and local ACK timeout
       values.  The minimum RNR NAK timer value is set to 0, for a delay of
       655 ms.  The local ACK timeout is calculated based on the packet
       lifetime and local HCA ACK delay.  The packet lifetime is determined
       by the InfiniBand Subnet Administrator and is part of the route (path
       record) information obtained by the active side of the connection.
       The HCA ACK delay is a property of the locally used HCA.

       The RNR retry count is a 3-bit value.

       The length of the private data provided by the user is limited to 196
       bytes for RDMA_PS_TCP, or 136 bytes for RDMA_PS_UDP.

SEE ALSO         top

       rdma_listen(3), rdma_reject(3), rdma_get_cm_event(3)

COLOPHON         top

       This page is part of the rdma-core (RDMA Core Userspace Libraries and
       Daemons) project.  Information about the project can be found at 
       ⟨https://github.com/linux-rdma/rdma-core⟩.  If you have a bug report
       for this manual page, send it to linux-rdma@vger.kernel.org.  This
       page was obtained from the project's upstream Git repository
       ⟨https://github.com/linux-rdma/rdma-core.git⟩ on 2019-09-26.  (At
       that time, the date of the most recent commit that was found in the
       repository was 2019-09-25.)  If you discover any rendering problems
       in this HTML version of the page, or you believe there is a better or
       more up-to-date source for the page, or you have corrections or
       improvements to the information in this COLOPHON (which is not part
       of the original manual page), send a mail to man-pages@man7.org

librdmacm                        2014-05-27                   RDMA_ACCEPT(3)

Pages that refer to this page: rdma_disconnect(3)rdma_get_dst_port(3)rdma_get_request(3)rdma_listen(3)rdma_notify(3)rdma_post_read(3)rdma_post_readv(3)rdma_post_send(3)rdma_post_sendv(3)rdma_post_ud_send(3)rdma_post_write(3)rdma_post_writev(3)rdma_reject(3)rdma_cm(7)