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/*-
* Copyright (c) 2001,2002,2003 Jonathan Lemon <jlemon@FreeBSD.org>
* Copyright (c) 1997, Stefan Esser <se@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.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/rtprio.h>
#include <sys/systm.h>
#include <sys/interrupt.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/random.h>
#include <sys/resourcevar.h>
#include <sys/sysctl.h>
#include <sys/unistd.h>
#include <machine/atomic.h>
#include <machine/cpu.h>
#include <machine/stdarg.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/if_types.h>
#include <net/if_var.h>
#include <net/netisr.h>
volatile unsigned int netisr; /* scheduling bits for network */
struct netisr {
netisr_t *ni_handler;
struct ifqueue *ni_queue;
} netisrs[32];
static struct mtx netisr_mtx;
static void *net_ih;
void
legacy_setsoftnet(void)
{
swi_sched(net_ih, 0);
}
void
netisr_register(int num, netisr_t *handler, struct ifqueue *inq)
{
KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))),
("bad isr %d", num));
netisrs[num].ni_handler = handler;
netisrs[num].ni_queue = inq;
}
void
netisr_unregister(int num)
{
struct netisr *ni;
int s;
KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))),
("bad isr %d", num));
ni = &netisrs[num];
ni->ni_handler = NULL;
if (ni->ni_queue != NULL) {
s = splimp();
IF_DRAIN(ni->ni_queue);
splx(s);
}
}
struct isrstat {
int isrs_count; /* dispatch count */
int isrs_directed; /* ...successfully dispatched */
int isrs_deferred; /* ...queued instead */
int isrs_bypassed; /* bypassed queued packets */
int isrs_queued; /* intentionally queueued */
int isrs_swi_count; /* swi_net handlers called */
};
static struct isrstat isrstat;
SYSCTL_NODE(_net, OID_AUTO, isr, CTLFLAG_RW, 0, "netisr counters");
static int netisr_enable = 0;
SYSCTL_INT(_net_isr, OID_AUTO, enable, CTLFLAG_RW,
&netisr_enable, 0, "enable direct dispatch");
SYSCTL_INT(_net_isr, OID_AUTO, count, CTLFLAG_RD,
&isrstat.isrs_count, 0, "");
SYSCTL_INT(_net_isr, OID_AUTO, directed, CTLFLAG_RD,
&isrstat.isrs_directed, 0, "");
SYSCTL_INT(_net_isr, OID_AUTO, deferred, CTLFLAG_RD,
&isrstat.isrs_deferred, 0, "");
SYSCTL_INT(_net_isr, OID_AUTO, bypassed, CTLFLAG_RD,
&isrstat.isrs_bypassed, 0, "");
SYSCTL_INT(_net_isr, OID_AUTO, queued, CTLFLAG_RD,
&isrstat.isrs_queued, 0, "");
SYSCTL_INT(_net_isr, OID_AUTO, swi_count, CTLFLAG_RD,
&isrstat.isrs_swi_count, 0, "");
/*
* Call the netisr directly instead of queueing the packet, if possible.
*
* Ideally, the permissibility of calling the routine would be determined
* by checking if splnet() was asserted at the time the device interrupt
* occurred; if so, this indicates that someone is in the network stack.
*
* However, bus_setup_intr uses INTR_TYPE_NET, which sets splnet before
* calling the interrupt handler, so the previous mask is unavailable.
* Approximate this by checking intr_nesting_level instead; if any SWI
* handlers are running, the packet is queued instead.
*/
void
netisr_dispatch(int num, struct mbuf *m)
{
struct netisr *ni;
isrstat.isrs_count++;
KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))),
("bad isr %d", num));
ni = &netisrs[num];
if (ni->ni_queue == NULL) {
m_freem(m);
return;
}
if (netisr_enable && mtx_trylock(&netisr_mtx)) {
isrstat.isrs_directed++;
/*
* One slight problem here is that packets might bypass
* each other in the stack, if an earlier one happened
* to get stuck in the queue.
*
* we can either:
* a. drain the queue before handling this packet,
* b. fallback to queueing the packet,
* c. sweep the issue under the rug and ignore it.
*
* Currently, we do c), and keep a rough event counter.
*/
if (_IF_QLEN(ni->ni_queue) > 0)
isrstat.isrs_bypassed++;
ni->ni_handler(m);
mtx_unlock(&netisr_mtx);
} else {
isrstat.isrs_deferred++;
if (IF_HANDOFF(ni->ni_queue, m, NULL))
schednetisr(num);
}
}
/*
* Same as above, but always queue.
* This is either used in places where we are not confident that
* direct dispatch is possible, or where queueing is required.
*/
int
netisr_queue(int num, struct mbuf *m)
{
struct netisr *ni;
KASSERT(!(num < 0 || num >= (sizeof(netisrs)/sizeof(*netisrs))),
("bad isr %d", num));
ni = &netisrs[num];
if (ni->ni_queue == NULL) {
m_freem(m);
return (1);
}
isrstat.isrs_queued++;
if (!IF_HANDOFF(ni->ni_queue, m, NULL))
return (0);
schednetisr(num);
return (1);
}
static void
swi_net(void *dummy)
{
struct netisr *ni;
struct mbuf *m;
u_int bits;
int i;
#ifdef DEVICE_POLLING
const int polling = 1;
#else
const int polling = 0;
#endif
mtx_lock(&netisr_mtx);
do {
bits = atomic_readandclear_int(&netisr);
if (bits == 0)
break;
while ((i = ffs(bits)) != 0) {
isrstat.isrs_swi_count++;
i--;
bits &= ~(1 << i);
ni = &netisrs[i];
if (ni->ni_handler == NULL) {
printf("swi_net: unregistered isr %d.\n", i);
continue;
}
if (ni->ni_queue == NULL)
ni->ni_handler(NULL);
else
for (;;) {
IF_DEQUEUE(ni->ni_queue, m);
if (m == NULL)
break;
ni->ni_handler(m);
}
}
} while (polling);
mtx_unlock(&netisr_mtx);
}
static void
start_netisr(void *dummy)
{
mtx_init(&netisr_mtx, "netisr lock", NULL, MTX_DEF);
if (swi_add(NULL, "net", swi_net, NULL, SWI_NET, 0, &net_ih))
panic("start_netisr");
}
SYSINIT(start_netisr, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_netisr, NULL)
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