Provided by: librdmacm-dev_1.0.14.1-2_amd64 bug

NAME

       rdma_accept - Called to accept a connection request.

SYNOPSIS

       #include <rdma/rdma_cma.h>

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

ARGUMENTS

       id          Connection identifier associated with the request.

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

DESCRIPTION

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

RETURN VALUE

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

NOTES

       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

       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.

       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 and
              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

       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.

SEE ALSO

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