mirror of
https://git.hardenedbsd.org/hardenedbsd/HardenedBSD.git
synced 2024-12-20 07:14:26 +01:00
141 lines
4.0 KiB
Groff
141 lines
4.0 KiB
Groff
.\" Copyright (c) 2009 Bitgravity Inc
|
|
.\" Written by: Kip Macy <kmacy@@FreeBSD.org>
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd September 27, 2012
|
|
.Dt DRBR 9
|
|
.Os
|
|
.Sh NAME
|
|
.Nm drbr ,
|
|
.Nm drbr_free ,
|
|
.Nm drbr_enqueue ,
|
|
.Nm drbr_dequeue ,
|
|
.Nm drbr_dequeue_cond ,
|
|
.Nm drbr_flush ,
|
|
.Nm drbr_empty ,
|
|
.Nm drbr_inuse ,
|
|
.Nd network driver interface to buf_ring
|
|
.Sh SYNOPSIS
|
|
.In sys/param.h
|
|
.In net/if.h
|
|
.In net/if_var.h
|
|
.Ft void
|
|
.Fn drbr_free "struct buf_ring *br" "struct malloc_type *type"
|
|
.Ft int
|
|
.Fn drbr_enqueue "struct ifnet *ifp" "struct buf_ring *br" "struct mbuf *m"
|
|
.Ft struct mbuf *
|
|
.Fn drbr_dequeue "struct ifnet *ifp" "struct buf_ring *br"
|
|
.Ft struct mbuf *
|
|
.Fn drbr_dequeue_cond "struct ifnet *ifp" "struct buf_ring *br" "int (*func) (struct mbuf *, void *)" "void *arg"
|
|
.Ft void
|
|
.Fn drbr_flush "struct ifnet *ifp" "struct buf_ring *br"
|
|
.Ft int
|
|
.Fn drbr_empty "struct ifnet *ifp" "struct buf_ring *br"
|
|
.Ft int
|
|
.Fn drbr_inuse "struct ifnet *ifp" "struct buf_ring *br"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
functions provide an API to network drivers for using
|
|
.Xr buf_ring 9
|
|
for enqueueing and dequeueing packets.
|
|
This is meant as a replacement for the IFQ interface for packet queuing.
|
|
It allows a packet to be enqueued with a single atomic and packet
|
|
dequeue to be done without any per-packet atomics as it is protected
|
|
by the driver's tx queue lock.
|
|
If
|
|
.Dv INVARIANTS
|
|
is enabled,
|
|
.Fn drbr_dequeue
|
|
will assert that the tx queue lock is held when it is called.
|
|
.Pp
|
|
The
|
|
.Fn drbr_free
|
|
function frees all the enqueued mbufs and then frees the buf_ring.
|
|
.Pp
|
|
The
|
|
.Fn drbr_enqueue
|
|
function is used to enqueue an mbuf to a buf_ring, falling back to the
|
|
ifnet's IFQ if
|
|
.Xr ALTQ 4
|
|
is enabled.
|
|
.Pp
|
|
The
|
|
.Fn drbr_dequeue
|
|
function is used to dequeue an mbuf from a buf_ring or, if
|
|
.Xr ALTQ 4
|
|
is enabled, from the ifnet's IFQ.
|
|
.Pp
|
|
The
|
|
.Fn drbr_dequeue_cond
|
|
function is used to conditionally dequeue an mbuf from a buf_ring based
|
|
on whether
|
|
.Fa func
|
|
returns
|
|
.Dv TRUE
|
|
or
|
|
.Dv FALSE .
|
|
.Pp
|
|
The
|
|
.Fn drbr_flush
|
|
function frees all mbufs enqueued in the buf_ring and the ifnet's IFQ.
|
|
.Pp
|
|
The
|
|
.Fn drbr_empty
|
|
function returns
|
|
.Dv TRUE
|
|
if there are no mbufs enqueued,
|
|
.Dv FALSE
|
|
otherwise.
|
|
.Pp
|
|
The
|
|
.Fn drbr_inuse
|
|
function returns the number of mbufs enqueued.
|
|
Note to users that this is intrinsically racy as there is no guarantee that
|
|
there will not be more mbufs when
|
|
.Fn drbr_dequeue
|
|
is actually called.
|
|
Provided the tx queue lock is held there will not be less.
|
|
.Sh RETURN VALUES
|
|
The
|
|
.Fn drbr_enqueue
|
|
function returns
|
|
.Er ENOBUFS
|
|
if there are no slots available in the buf_ring and
|
|
.Dv 0
|
|
on success.
|
|
.Pp
|
|
The
|
|
.Fn drbr_dequeue
|
|
and
|
|
.Fn drbr_dequeue_cond
|
|
functions return an mbuf on success and
|
|
.Dv NULL
|
|
if the buf_ring is empty.
|
|
.Sh HISTORY
|
|
These functions were introduced in
|
|
.Fx 8.0 .
|