Provided by: librdmacm-dev_1.0.8-1_i386 bug

NAME

       rdma_cm - RDMA communication manager.

SYNOPSIS

       #include <rdma/rdma_cma.h>

DESCRIPTION

       Used to establish communication over RDMA transports.

NOTES

       The  RDMA  CM  is  a  communication  manager  used  to  setup reliable,
       connected and unreliable datagram data transfers.  It provides an  RDMA
       transport  neutral  interface for establishing connections.  The API is
       based on sockets, but adapted for  queue  pair  (QP)  based  semantics:
       communication  must  be over a specific RDMA device, and data transfers
       are message based.

       The RDMA CM only  provides  the  communication  management  (connection
       setup / teardown) portion of an RDMA API.  It works in conjunction with
       the verbs API  defined  by  the  libibverbs  library.   The  libibverbs
       library provides the interfaces needed to send and receive data.

CLIENT OPERATION

       This section provides a general overview of the basic operation for the
       active, or client, side of communication.  A  general  connection  flow
       would be:

       rdma_create_event_channel
              create channel to receive events

       rdma_create_id
              allocate an rdma_cm_id, this is conceptually similar to a socket

       rdma_resolve_addr
              obtain a local RDMA device to reach the remote address

       rdma_get_cm_event
              wait for RDMA_CM_EVENT_ADDR_RESOLVED event

       rdma_ack_cm_event
              ack event

       rdma_create_qp
              allocate a QP for the communication

       rdma_resolve_route
              determine the route to the remote address

       rdma_get_cm_event
              wait for RDMA_CM_EVENT_ROUTE_RESOLVED event

       rdma_ack_cm_event
              ack event

       rdma_connect
              connect to the remote server

       rdma_get_cm_event
              wait for RDMA_CM_EVENT_ESTABLISHED event

       rdma_ack_cm_event
              ack event

       Perform data transfers over connection

       rdma_disconnect
              tear-down connection

       rdma_get_cm_event
              wait for RDMA_CM_EVENT_DISCONNECTED event

       rdma_ack_cm_event
              ack event

       rdma_destroy_qp
              destroy the QP

       rdma_destroy_id
              release the rdma_cm_id

       rdma_destroy_event_channel
              release the event channel

       An almost identical process is used to setup unreliable  datagram  (UD)
       communication  between  nodes.   No actual connection is formed between
       QPs however, so disconnection is not needed.

       Although this example  shows  the  client  initiating  the  disconnect,
       either side of a connection may initiate the disconnect.

SERVER OPERATION

       This section provides a general overview of the basic operation for the
       passive, or server, side of communication.  A general  connection  flow
       would be:

       rdma_create_event_channel
              create channel to receive events

       rdma_create_id
              allocate an rdma_cm_id, this is conceptually similar to a socket

       rdma_bind_addr
              set the local port number to listen on

       rdma_listen
              begin listening for connection requests

       rdma_get_cm_event
              wait  for  RDMA_CM_EVENT_CONNECT_REQUEST  event   with   a   new
              rdma_cm_id

       rdma_create_qp
              allocate a QP for the communication on the new rdma_cm_id

       rdma_accept
              accept the connection request

       rdma_ack_cm_event
              ack event

       rdma_get_cm_event
              wait for RDMA_CM_EVENT_ESTABLISHED event

       rdma_ack_cm_event
              ack event

       Perform data transfers over connection

       rdma_get_cm_event
              wait for RDMA_CM_EVENT_DISCONNECTED event

       rdma_ack_cm_event
              ack event

       rdma_disconnect
              tear-down connection

       rdma_destroy_qp
              destroy the QP

       rdma_destroy_id
              release the connected rdma_cm_id

       rdma_destroy_id
              release the listening rdma_cm_id

       rdma_destroy_event_channel
              release the event channel

RETURN CODES

       =  0   success

       = -1   error - see errno for more details

       < -1   error - see include/asm-generic/errno*.h for more details

       Librdmacm functions return 0 to indicate success, and a negative return
       value to indicate failure.  If a function  operates  asynchronously,  a
       return  value  of  0 means that the operation was successfully started.
       The operation could still complete in error;  users  should  check  the
       status of the related event.  If the return value is -1, then errno can
       be examined for additional information regarding  the  reason  for  the
       failure.   If  the  return value is < -1, then additional error reasons
       can be obtained by comparing the returned value with the values  listed
       in include/asm-generic/errno-base.h and include/asm-generic/errno.h.

SEE ALSO

       rdma_create_event_channel(3),  rdma_get_cm_event(3), rdma_create_id(3),
       rdma_resolve_addr(3),       rdma_bind_addr(3),       rdma_create_qp(3),
       rdma_resolve_route(3), rdma_connect(3), rdma_listen(3), rdma_accept(3),
       rdma_reject(3),    rdma_join_multicast(3),     rdma_leave_multicast(3),
       rdma_notify(3),        rdma_ack_cm_event(3),        rdma_disconnect(3),
       rdma_destroy_qp(3), rdma_destroy_id(3),  rdma_destroy_event_channel(3),
       rdma_get_devices(3),    rdma_free_devices(3),    rdma_get_peer_addr(3),
       rdma_get_local_addr(3),   rdma_get_dst_port(3),   rdma_get_src_port(3),
       rdma_set_option(3) ucmatose(1), udaddy(1), mckey(1), rping(1)