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

NAME

       rdma_connect - Initiate an active connection request.

SYNOPSIS

       #include <rdma/rdma_cma.h>

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

ARGUMENTS

       id          RDMA identifier.

       conn_param  connection parameters.  See CONNECTION PROPERTIES below for details.

DESCRIPTION

       For  an  rdma_cm_id  of  type  RDMA_PS_TCP,  this call initiates a connection request to a
       remote destination.  For an rdma_cm_id of type RDMA_PS_UDP, it initiates a lookup  of  the
       remote QP providing the datagram service.

RETURN VALUE

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

NOTES

       Users  must  have  resolved  a  route  to  the  destination  address  by   having   called
       rdma_resolve_route or rdma_create_ep before calling this routine.

CONNECTION PROPERTIES

       The  following  properties  are  used  to configure the communication and specified by the
       conn_param parameter when connecting or establishing datagram communication.

       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
              remote  RDMA  device attribute max_qp_init_rd_atom.  The remote endpoint can adjust
              this value when accepting the connection.

       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
              remote  RDMA  device attribute max_qp_rd_atom.  The remote endpoint can adjust this
              value when accepting the connection.

       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
              The maximum number of times that a data transfer operation should be retried on the
              connection when an error occurs.  This setting controls  the  number  of  times  to
              retry  send,  RDMA,  and  atomic  operations  when timeouts occur.  Applies only to
              RDMA_PS_TCP.

       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.   Applies  only  to
              RDMA_PS_TCP.

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 resolved route (path record) information.  The HCA
       ACK delay is a property of the locally used HCA.

       Retry count and RNR retry count values are 3-bit values.

IWARP SPECIFIC

       Connections established over iWarp RDMA devices currently require that the active side  of
       the connection send the first message.

SEE ALSO

       rdma_cm(7),  rdma_create_id(3), rdma_resolve_route(3), rdma_disconnect(3), rdma_listen(3),
       rdma_get_cm_event(3)