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

NAME

       rdma_get_cm_event - Retrieves the next pending communication event.

SYNOPSIS

       #include <rdma/rdma_cma.h>

       int   rdma_get_cm_event  (struct  rdma_event_channel  *channel,  struct
       rdma_cm_event **event);

ARGUMENTS

       channel     Event channel to check for events.

       event       Allocated information about the next communication event.

DESCRIPTION

       Retrieves a communication event.  If no events are pending, by default,
       the call will block until an event is received.

NOTES

       The  default  synchronous  behavior  of  this routine can be changed by
       modifying the file descriptor associated with the given  channel.   All
       events   that   are   reported   must   be   acknowledged   by  calling
       rdma_ack_cm_event.  Destruction  of  an  rdma_cm_id  will  block  until
       related events have been acknowledged.

EVENT DATA

       Communication   event   details   are  returned  in  the  rdma_cm_event
       structure.  This structure is allocated by the rdma_cm and released  by
       the  rdma_ack_cm_event routine.  Details of the rdma_cm_event structure
       are given below.

       id          The rdma_cm identifier associated with the event.   If  the
                   event  type  is  RDMA_CM_EVENT_CONNECT_REQUEST,  then  this
                   references a new id for that communication.

       listen_id   For   RDMA_CM_EVENT_CONNECT_REQUEST   event   types,   this
                   references  the corresponding listening request identifier.

       event       Specifies the type of communication event  which  occurred.
                   See EVENT TYPES below.

       status      Returns  any asynchronous error information associated with
                   an event.  The status  is  zero  unless  the  corresponding
                   operation failed.

       param       Provides  additional  details  based  on the type of event.
                   Users should select the conn or ud subfields based  on  the
                   rdma_port_space  of  the  rdma_cm_id  associated  with  the
                   event.  See UD EVENT DATA and CONN EVENT DATA below.

UD EVENT DATA

       Event  parameters  related  to  unreliable  datagram   (UD)   services:
       RDMA_PS_UDP  and  RDMA_PS_IPOIB.   The  UD  event  data  is  valid  for
       RDMA_CM_EVENT_ESTABLISHED  and   RDMA_CM_EVENT_MULTICAST_JOIN   events,
       unless stated otherwise.

       private_data
                   References   any   user-specified   data   associated  with
                   RDMA_CM_EVENT_CONNECT_REQUEST or  RDMA_CM_EVENT_ESTABLISHED
                   events.   The  data  referenced  by this field matches that
                   specified by the remote side when calling  rdma_connect  or
                   rdma_accept.   This  field  is  NULL  if the event does not
                   include  private  data.   The  buffer  referenced  by  this
                   pointer is deallocated when calling rdma_ack_cm_event.

       private_data_len
                   The  size  of  the  private data buffer.  Users should note
                   that the size of the private data buffer may be larger than
                   the  amount  of  private data sent by the remote side.  Any
                   additional space in the buffer will be zeroed out.

       ah_attr     Address information needed  to  send  data  to  the  remote
                   endpoint(s).    Users   should   use  this  structure  when
                   allocating their address handle.

       qp_num      QP number of the remote endpoint or multicast group.

       qkey        QKey needed to send data to the remote endpoint(s).

CONN EVENT DATA

       Event parameters related to connected QP  services:  RDMA_PS_TCP.   The
       connection      related      event      data      is      valid     for
       RDMA_CM_EVENT_CONNECT_REQUEST  and  RDMA_CM_EVENT_ESTABLISHED   events,
       unless stated otherwise.

       private_data
                   References  any  user-specified  data  associated  with the
                   event.  The data referenced  by  this  field  matches  that
                   specified  by  the remote side when calling rdma_connect or
                   rdma_accept.  This field is NULL  if  the  event  does  not
                   include  private  data.   The  buffer  referenced  by  this
                   pointer is deallocated when calling rdma_ack_cm_event.

       private_data_len
                   The size of the private data  buffer.   Users  should  note
                   that the size of the private data buffer may be larger than
                   the amount of private data sent by the  remote  side.   Any
                   additional space in the buffer will be zeroed out.

       responder_resources
                   The   number   of  responder  resources  requested  of  the
                   recipient.   This  field  matches   the   initiator   depth
                   specified  by the remote node when calling rdma_connect and
                   rdma_accept.

       initiator_depth
                   The  maximum  number  of   outstanding   RDMA   read/atomic
                   operations  that  the recipient may have outstanding.  This
                   field matches the  responder  resources  specified  by  the
                   remote node when calling rdma_connect and rdma_accept.

       flow_control
                   Indicates if hardware level flow control is provided by the
                   sender.

       retry_count For RDMA_CM_EVENT_CONNECT_REQUEST  events  only,  indicates
                   the  number  of  times that the recipient should retry send
                   operations.

       rnr_retry_count
                   The  number  of  times  that  the  recipient  should  retry
                   receiver not ready (RNR) NACK errors.

       srq         Specifies if the sender is using a shared-receive queue.

       qp_num      Indicates the remote QP number for the connection.

EVENT TYPES

       The following types of communication events may be reported.

       RDMA_CM_EVENT_ADDR_RESOLVED
              Address resolution (rdma_resolve_addr) completed successfully.

       RDMA_CM_EVENT_ADDR_ERROR
              Address resolution (rdma_resolve_addr) failed.

       RDMA_CM_EVENT_ROUTE_RESOLVED
              Route resolution (rdma_resolve_route) completed successfully.

       RDMA_CM_EVENT_ROUTE_ERROR
              Route resolution (rdma_resolve_route) failed.

       RDMA_CM_EVENT_CONNECT_REQUEST
              Generated  on  the  passive  side  to  notify  the user of a new
              connection request.

       RDMA_CM_EVENT_CONNECT_RESPONSE
              Generated on the active side to notify the user of a  successful
              response  to  a  connection  request.   It  is only generated on
              rdma_cm_id’s that do not have a QP associated with them.

       RDMA_CM_EVENT_CONNECT_ERROR
              Indicates that an error has occurred trying to  establish  or  a
              connection.  May be generated on the active or passive side of a
              connection.

       RDMA_CM_EVENT_UNREACHABLE
              Generated on the active side to notify the user that the  remote
              server  is  not  reachable  or unable to respond to a connection
              request.

       RDMA_CM_EVENT_REJECTED
              Indicates that a connection request or response was rejected  by
              the remote end point.

       RDMA_CM_EVENT_ESTABLISHED
              Indicates that a connection has been established with the remote
              end point.

       RDMA_CM_EVENT_DISCONNECTED
              The connection has been disconnected.

       RDMA_CM_EVENT_DEVICE_REMOVAL
              The local RDMA device associated with the  rdma_cm_id  has  been
              removed.   Upon  receiving this event, the user must destroy the
              related rdma_cm_id.

       RDMA_CM_EVENT_MULTICAST_JOIN
              The multicast  join  operation  (rdma_join_multicast)  completed
              successfully.

       RDMA_CM_EVENT_MULTICAST_ERROR
              An  error  either occurred joining a multicast group, or, if the
              group had already  been  joined,  on  an  existing  group.   The
              specified  multicast group is no longer accessible and should be
              rejoined, if desired.

       RDMA_CM_EVENT_ADDR_CHANGE
              The network device  associated  with  this  ID  through  address
              resolution  changed  its  HW  address,  eg  following of bonding
              failover. This event can serve as a hint  for  applications  who
              want  the  links  used for their RDMA sessions to align with the
              network stack.

       RDMA_CM_EVENT_TIMEWAIT_EXIT
              The QP associated with a  connection  has  exited  its  timewait
              state  and  is  now  ready  to  be re-used.  After a QP has been
              disconnected, it is maintained in a timewait state to allow  any
              in flight packets to exit the network.  After the timewait state
              has completed, the rdma_cm will report this event.

SEE ALSO

       rdma_ack_cm_event(3),                     rdma_create_event_channel(3),
       rdma_resolve_addr(3),      rdma_resolve_route(3),      rdma_connect(3),
       rdma_listen(3),       rdma_join_multicast(3),       rdma_destroy_id(3),
       rdma_event_str(3)