NAME
ifq_enqueue,
ifq_dequeue, ifq_purge,
ifq_len, ifq_empty,
ifq_hdatalen,
ifq_set_oactive,
ifq_clr_oactive,
ifq_is_oactive, ifq_restart,
ifq_barrier —
interface send queue API
SYNOPSIS
#include
<net/if_var.h>
int
ifq_enqueue(struct
ifqueue *ifq, struct mbuf
*m);
struct mbuf *
ifq_dequeue(struct
ifqueue *ifq);
unsigned int
ifq_purge(struct
ifqueue *ifq);
unsigned int
ifq_len(struct
ifqueue *ifq);
unsigned int
ifq_empty(struct
ifqueue *ifq);
int
ifq_hdatalen(struct
ifqueue *ifq);
void
ifq_set_oactive(struct
ifqueue *ifq);
void
ifq_clr_oactive(struct
ifqueue *ifq);
unsigned int
ifq_is_oactive(struct
ifqueue *ifq);
void
ifq_restart(struct
ifqueue *ifq);
void
ifq_barrier(struct
ifqueue *ifq);
DESCRIPTION
The ifqueue API provides implementations of data structures and operations for the network stack to queue mbufs for a network driver to dequeue from its start routine for transmission.
ifq_enqueue(struct ifqueue *ifq, struct mbuf *m)- Enqueue mbuf m on the ifq interface send queue. If the queue rejects the packet, it will be freed with m_freem(9) and counted as a drop.
ifq_dequeue(struct ifqueue *ifq)- Dequeue the next mbuf to be transmitted from the ifq interface send queue.
ifq_purge(struct ifqueue *ifq)- Free all the mbufs on the interface send queue ifq. Freed mbufs will be accounted as drops.
ifq_len(struct ifqueue *ifq)- Return the number of mbufs on the interface send queue
ifq. Note that while
ifq_len() may report that mbufs are on the queue, the current queue discipline may not make them available for dequeueing withifq_dequeue() orifq_deq_begin(). ifq_empty(struct ifqueue *ifq)- Return if the interface send queue ifq is empty.
ifq_hdatalen(struct ifqueue *ifq)- Return the number of bytes in the mbuf at the head of the interface send queue ifq.
ifq_set_oactive(struct ifqueue *ifq)ifq_set_oactive() is called by the relevant driver to mark the hardware associated with the interface send queue ifq as unable to transmit more packets.ifq_clr_oactive(struct ifqueue *ifq)ifq_clr_oactive() is called by the relevant driver to clear the "active" mark on the hardware associated with the interface send queue ifq, meaning it is now able to transmit packets.ifq_is_oactive(struct ifqueue *ifq)- Return if the hardware associated with the interface send queue ifq is unable to transmit more packets.
ifq_restart(struct ifqueue *ifq)- Dispatch a call to
ifq_clr_oactive() and the interface's start routine. This call is serialised with other calls to the start routine viaif_start() and therefore provides race free modification of the "active" mark. ifq_barrier(struct ifqueue *ifq)ifq_barrier() guarantees that any work currently running in the interface queue serialiser (e.g. work dispatched byifq_restart() or the interface's start routine) has finished beforeifq_barrier() returns.
CONTEXT
ifq_enqueue(),
ifq_dequeue(), ifq_purge(),
ifq_len(), ifq_empty(),
ifq_hdatalen(),
ifq_set_oactive(),
ifq_clr_oactive(),
ifq_is_oactive(), and
ifq_restart() can be called during autoconf, from
process context, or from interrupt context.
ifq_barrier() can be called from process
context.
RETURN VALUES
ifq_enqueue() returns 0 if the mbuf was
successfully queued, or non-zero if mbuf was freed.
ifq_dequeue() returns the next mbuf to be
transmitted by the interface. If no packet is available for transmission,
NULL is returned.
ifq_purge() returns the number of mbufs
that were removed from the queue and freed.
ifq_len() returns the number of mbufs on
the queue.
ifq_empty() returns a non-zero value if
the queue is empty, otherwise 0.
ifq_hdatalen() returns the size of a
packet on the queue, or 0 if the queue is empty;
ifq_is_oactive() returns a non-zero value
if the hardware associated with the interface send queue is unable to
transmit more packets, otherwise 0.