.\" $OpenBSD: ifiq_input.9,v 1.4 2022/03/31 17:27:23 naddy Exp $
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.\" Copyright (c) 2020 David Gwynne <dlg@openbsd.org>
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.Dd $Mdocdate: March 31 2022 $
.Dt IFIQ_INPUT 9
.Os
.Sh NAME
.Nm ifiq_input ,
.Nm ifiq_enqueue
.Nd network interface input queue (ifiqueue) API
.Sh SYNOPSIS
.In net/if_var.h
.Ft int
.Fn ifiq_input "struct ifiqueue *ifiq" "struct mbuf_list *ml"
.Ft void
.Fn ifiq_enqueue "struct ifiqueue *ifiq" "struct mbuf *m"
.Sh DESCRIPTION
The network interface input queue (ifiqueue) API provides functions
for network drivers to queue received packets for processing by the
network stack.
.Bl -tag -width Ds
.It Fn ifiq_input "struct ifiqueue *ifq" "struct mbuf_list *ml"
Enqueue the list of mbufs in
.Fa ml
on the
.Fa ifiq
interface input queue and notify the network stack to process them.
If the queue rejects the packets, they will be freed
and counted as drops.
.It Fn ifiq_enqueue "struct ifiqueue *ifq" "struct mbuf *m"
Enqueue the mbuf
.Fa m
on the
.Fa ifiq
interface input queue and notify the network stack to process it.
.El
.Sh CONTEXT
.Fn ifiq_input
and
.Fn ifiq_enqueue
can be called during autoconf, from process context, or from interrupt context.
.Sh RETURN VALUES
.Fn ifiq_input
returns a non-zero value if mbufs are queued too rapidly for the
stack to process.
If possible, the caller should attempt to reduce the number of mbufs
being generated in the future.
For example, if mbufs are being received from
hardware managed with the interface RX ring API,
.Xr if_rxr_livelocked 9
can be called to indicate to the hardware that backpressure is required.
.Sh SEE ALSO
.Xr if_rxr_livelocked 9