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NAME | SYNOPSIS | ARGUMENTS | DESCRIPTION | RETURN VALUE | NOTES | CONNECTION PROPERTIES | INFINIBAND SPECIFIC | SEE ALSO | COLOPHON |
RDMA_ACCEPT(3) Librdmacm Programmer's Manual RDMA_ACCEPT(3)
rdma_accept - Called to accept a connection request.
#include <rdma/rdma_cma.h>
int rdma_accept (struct rdma_cm_id *id, struct rdma_conn_param
*conn_param);
id Connection identifier associated with the request.
conn_param Information needed to establish the connection. See
CONNECTION PROPERTIES below for details.
Called from the listening side to accept a connection or datagram
service lookup request.
Returns 0 on success, or -1 on error. If an error occurs, errno will
be set to indicate the failure reason.
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.
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.
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.
rdma_listen(3), rdma_reject(3), rdma_get_cm_event(3)
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 2020-08-13. (At
that time, the date of the most recent commit that was found in the
repository was 2020-08-05.) 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)