2 * Copyright (C) 2013 Universita` di Pisa. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * This module implements netmap support on top of standard,
28 * unmodified device drivers.
30 * A NIOCREGIF request is handled here if the device does not
31 * have native support. TX and RX rings are emulated as follows:
34 * We preallocate a block of TX mbufs (roughly as many as
35 * tx descriptors; the number is not critical) to speed up
36 * operation during transmissions. The refcount on most of
37 * these buffers is artificially bumped up so we can recycle
38 * them more easily. Also, the destructor is intercepted
39 * so we use it as an interrupt notification to wake up
40 * processes blocked on a poll().
42 * For each receive ring we allocate one "struct mbq"
43 * (an mbuf tailq plus a spinlock). We intercept packets
45 * on the receive path and put them in the mbq from which
46 * netmap receive routines can grab them.
49 * in the generic_txsync() routine, netmap buffers are copied
50 * (or linked, in a future) to the preallocated mbufs
51 * and pushed to the transmit queue. Some of these mbufs
52 * (those with NS_REPORT, or otherwise every half ring)
53 * have the refcount=1, others have refcount=2.
54 * When the destructor is invoked, we take that as
55 * a notification that all mbufs up to that one in
56 * the specific ring have been completed, and generate
57 * the equivalent of a transmit interrupt.
63 /* __FBSDID("$FreeBSD: head/sys/dev/netmap/netmap.c 257666 2013-11-05 01:06:22Z luigi $"); */
65 #include <sys/types.h>
66 #include <sys/errno.h>
67 #include <sys/malloc.h>
68 #include <sys/lock.h> /* PROT_EXEC */
69 #include <sys/socket.h> /* sockaddrs */
70 #include <sys/event.h>
72 #include <net/if_var.h>
73 #include <sys/bus.h> /* bus_dmamap_* in netmap_kern.h */
75 // XXX temporary - D() defined here
76 #include <net/netmap.h>
77 #include "netmap_kern.h"
78 #include "netmap_mem2.h"
80 #define rtnl_lock() D("rtnl_lock called");
81 #define rtnl_unlock() D("rtnl_lock called");
82 #define MBUF_TXQ(m) ((m)->m_pkthdr.hash)
90 * we allocate an EXT_PACKET
92 #define netmap_get_mbuf(len) m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR)
94 /* mbuf destructor, also need to change the type to EXT_EXTREF,
95 * add an M_NOFREE flag, and then clear the flag and
96 * chain into uma_zfree(zone_pack, mf)
97 * (or reinstall the buffer ?)
99 #define SET_MBUF_DESTRUCTOR(m, fn) do { \
100 (m)->m_ext.ext_free = (void *)fn; \
101 /* (m)->m_ext.ext_type = EXT_EXTREF; */ \
105 #define GET_MBUF_REFCNT(m) ((m)->m_ext.ref_cnt ? *(m)->m_ext.ref_cnt : -1)
107 /* ======================== usage stats =========================== */
113 unsigned long txsync;
117 unsigned long rxsync;
120 struct rate_context {
122 struct timer_list timer;
123 struct rate_stats new;
124 struct rate_stats old;
127 #define RATE_PRINTK(_NAME_) \
128 printk( #_NAME_ " = %lu Hz\n", (cur._NAME_ - ctx->old._NAME_)/RATE_PERIOD);
129 #define RATE_PERIOD 2
130 static void rate_callback(unsigned long arg)
132 struct rate_context * ctx = (struct rate_context *)arg;
133 struct rate_stats cur = ctx->new;
145 r = mod_timer(&ctx->timer, jiffies +
146 msecs_to_jiffies(RATE_PERIOD * 1000));
148 D("[v1000] Error: mod_timer()");
151 static struct rate_context rate_ctx;
158 /* =============== GENERIC NETMAP ADAPTER SUPPORT ================= */
159 #define GENERIC_BUF_SIZE netmap_buf_size /* Size of the mbufs in the Tx pool. */
162 * Wrapper used by the generic adapter layer to notify
163 * the poller threads. Differently from netmap_rx_irq(), we check
164 * only IFCAP_NETMAP instead of NAF_NATIVE_ON to enable the irq.
167 netmap_generic_irq(struct ifnet *ifp, u_int q, u_int *work_done)
169 if (unlikely(!(ifp->if_capenable & IFCAP_NETMAP)))
172 return netmap_common_irq(ifp, q, work_done);
176 /* Enable/disable netmap mode for a generic network interface. */
177 int generic_netmap_register(struct netmap_adapter *na, int enable)
179 struct ifnet *ifp = na->ifp;
180 struct netmap_generic_adapter *gna = (struct netmap_generic_adapter *)na;
189 error = ifp->netdev_ops->ndo_stop(ifp);
193 #endif /* REG_RESET */
195 if (enable) { /* Enable netmap mode. */
196 /* Initialize the rx queue, as generic_rx_handler() can
197 * be called as soon as netmap_catch_rx() returns.
199 for (r=0; r<na->num_rx_rings; r++) {
200 mbq_safe_init(&na->rx_rings[r].rx_queue);
201 na->rx_rings[r].nr_ntc = 0;
204 /* Init the mitigation timer. */
205 netmap_mitigation_init(gna);
208 * Preallocate packet buffers for the tx rings.
210 for (r=0; r<na->num_tx_rings; r++) {
211 na->tx_rings[r].nr_ntc = 0;
212 na->tx_rings[r].tx_pool = kmalloc(na->num_tx_desc * sizeof(struct mbuf *),
213 M_DEVBUF, M_NOWAIT | M_ZERO);
214 if (!na->tx_rings[r].tx_pool) {
215 D("tx_pool allocation failed");
219 for (i=0; i<na->num_tx_desc; i++) {
220 m = netmap_get_mbuf(GENERIC_BUF_SIZE);
222 D("tx_pool[%d] allocation failed", i);
226 na->tx_rings[r].tx_pool[i] = m;
230 /* Prepare to intercept incoming traffic. */
231 error = netmap_catch_rx(na, 1);
233 D("netdev_rx_handler_register() failed");
234 goto register_handler;
236 ifp->if_capenable |= IFCAP_NETMAP;
238 /* Make netmap control the packet steering. */
239 netmap_catch_packet_steering(gna, 1);
244 if (rate_ctx.refcount == 0) {
246 memset(&rate_ctx, 0, sizeof(rate_ctx));
247 setup_timer(&rate_ctx.timer, &rate_callback, (unsigned long)&rate_ctx);
248 if (mod_timer(&rate_ctx.timer, jiffies + msecs_to_jiffies(1500))) {
249 D("Error: mod_timer()");
255 } else { /* Disable netmap mode. */
258 ifp->if_capenable &= ~IFCAP_NETMAP;
260 /* Release packet steering control. */
261 netmap_catch_packet_steering(gna, 0);
263 /* Do not intercept packets on the rx path. */
264 netmap_catch_rx(na, 0);
268 /* Free the mbufs going to the netmap rings */
269 for (r=0; r<na->num_rx_rings; r++) {
270 mbq_safe_purge(&na->rx_rings[r].rx_queue);
271 mbq_safe_destroy(&na->rx_rings[r].rx_queue);
274 netmap_mitigation_cleanup(gna);
276 for (r=0; r<na->num_tx_rings; r++) {
277 for (i=0; i<na->num_tx_desc; i++) {
278 m_freem(na->tx_rings[r].tx_pool[i]);
280 kfree(na->tx_rings[r].tx_pool, M_DEVBUF);
284 if (--rate_ctx.refcount == 0) {
286 del_timer(&rate_ctx.timer);
292 error = ifp->netdev_ops->ndo_open(ifp);
304 i = na->num_tx_desc; /* Useless, but just to stay safe. */
309 m_freem(na->tx_rings[r].tx_pool[i]);
311 kfree(na->tx_rings[r].tx_pool, M_DEVBUF);
312 i = na->num_tx_desc - 1;
319 * Callback invoked when the device driver frees an mbuf used
320 * by netmap to transmit a packet. This usually happens when
321 * the NIC notifies the driver that transmission is completed.
324 generic_mbuf_destructor(struct mbuf *m)
327 D("Tx irq (%p) queue %d", m, MBUF_TXQ(m));
328 netmap_generic_irq(MBUF_IFP(m), MBUF_TXQ(m), NULL);
330 m->m_ext.ext_type = EXT_PACKET;
332 m->m_ext.ext_free = NULL;
334 if (*(m->m_ext.ref_cnt) == 0)
335 *(m->m_ext.ref_cnt) = 1;
336 uma_zfree(zone_pack, m);
338 IFRATE(rate_ctx.new.txirq++);
341 /* Record completed transmissions and update hwavail.
343 * nr_ntc is the oldest tx buffer not yet completed
344 * (same as nr_hwavail + nr_hwcur + 1),
345 * nr_hwcur is the first unsent buffer.
346 * When cleaning, we try to recover buffers between nr_ntc and nr_hwcur.
349 generic_netmap_tx_clean(struct netmap_kring *kring)
351 u_int num_slots = kring->nkr_num_slots;
352 u_int ntc = kring->nr_ntc;
353 u_int hwcur = kring->nr_hwcur;
355 struct mbuf **tx_pool = kring->tx_pool;
357 while (ntc != hwcur) { /* buffers not completed */
358 struct mbuf *m = tx_pool[ntc];
360 if (unlikely(m == NULL)) {
361 /* try to replenish the entry */
362 tx_pool[ntc] = m = netmap_get_mbuf(GENERIC_BUF_SIZE);
363 if (unlikely(m == NULL)) {
364 D("mbuf allocation failed, XXX error");
365 // XXX how do we proceed ? break ?
369 } else if (GET_MBUF_REFCNT(m) != 1) {
370 break; /* This mbuf is still busy: its refcnt is 2. */
373 if (unlikely(++ntc == num_slots)) {
379 kring->nr_hwavail += n;
380 ND("tx completed [%d] -> hwavail %d", n, kring->nr_hwavail);
387 * We have pending packets in the driver between nr_ntc and j.
388 * Compute a position in the middle, to be used to generate
392 generic_tx_event_middle(struct netmap_kring *kring, u_int hwcur)
394 u_int n = kring->nkr_num_slots;
395 u_int ntc = kring->nr_ntc;
399 e = (hwcur + ntc) / 2;
400 } else { /* wrap around */
401 e = (hwcur + n + ntc) / 2;
407 if (unlikely(e >= n)) {
408 D("This cannot happen");
416 * We have pending packets in the driver between nr_ntc and hwcur.
417 * Schedule a notification approximately in the middle of the two.
418 * There is a race but this is only called within txsync which does
422 generic_set_tx_event(struct netmap_kring *kring, u_int hwcur)
427 if (kring->nr_ntc == hwcur) {
430 e = generic_tx_event_middle(kring, hwcur);
432 m = kring->tx_pool[e];
434 /* This can happen if there is already an event on the netmap
435 slot 'e': There is nothing to do. */
438 ND("Event at %d mbuf %p refcnt %d", e, m, GET_MBUF_REFCNT(m));
439 kring->tx_pool[e] = NULL;
440 SET_MBUF_DESTRUCTOR(m, generic_mbuf_destructor);
443 /* Decrement the refcount an free it if we have the last one. */
450 * generic_netmap_txsync() transforms netmap buffers into mbufs
451 * and passes them to the standard device driver
452 * (ndo_start_xmit() or ifp->if_transmit() ).
453 * On linux this is not done directly, but using dev_queue_xmit(),
454 * since it implements the TX flow control (and takes some locks).
457 generic_netmap_txsync(struct netmap_adapter *na, u_int ring_nr, int flags)
459 struct ifnet *ifp = na->ifp;
460 struct netmap_kring *kring = &na->tx_rings[ring_nr];
461 struct netmap_ring *ring = kring->ring;
462 u_int j, k, num_slots = kring->nkr_num_slots;
465 IFRATE(rate_ctx.new.txsync++);
467 // TODO: handle the case of mbuf allocation failure
468 /* first, reclaim completed buffers */
469 generic_netmap_tx_clean(kring);
471 /* Take a copy of ring->cur now, and never read it again. */
473 if (unlikely(k >= num_slots)) {
474 return netmap_ring_reinit(kring);
480 * 'new_slots' counts how many new slots have been added:
481 * everything from hwcur to cur, excluding reserved ones, if any.
482 * nr_hwreserved start from hwcur and counts how many slots were
483 * not sent to the NIC from the previous round.
485 new_slots = k - j - kring->nr_hwreserved;
487 new_slots += num_slots;
491 /* Process new packets to send:
492 * j is the current index in the netmap ring.
495 struct netmap_slot *slot = &ring->slot[j]; /* Current slot in the netmap ring */
496 void *addr = NMB(slot);
497 u_int len = slot->len;
501 if (unlikely(addr == netmap_buffer_base || len > NETMAP_BUF_SIZE)) {
502 return netmap_ring_reinit(kring);
504 /* Tale a mbuf from the tx pool and copy in the user packet. */
505 m = kring->tx_pool[j];
507 RD(5, "This should never happen");
508 kring->tx_pool[j] = m = netmap_get_mbuf(GENERIC_BUF_SIZE);
509 if (unlikely(m == NULL)) {
510 D("mbuf allocation failed");
514 /* XXX we should ask notifications when NS_REPORT is set,
515 * or roughly every half frame. We can optimize this
516 * by lazily requesting notifications only when a
517 * transmission fails. Probably the best way is to
518 * break on failures and set notifications when
519 * ring->avail == 0 || j != k
521 tx_ret = generic_xmit_frame(ifp, m, addr, len, ring_nr);
522 if (unlikely(tx_ret)) {
523 RD(5, "start_xmit failed: err %d [%u,%u,%u,%u]",
524 tx_ret, kring->nr_ntc, j, k, kring->nr_hwavail);
526 * No room for this mbuf in the device driver.
527 * Request a notification FOR A PREVIOUS MBUF,
528 * then call generic_netmap_tx_clean(kring) to do the
529 * double check and see if we can free more buffers.
530 * If there is space continue, else break;
531 * NOTE: the double check is necessary if the problem
532 * occurs in the txsync call after selrecord().
533 * Also, we need some way to tell the caller that not
534 * all buffers were queued onto the device (this was
535 * not a problem with native netmap driver where space
536 * is preallocated). The bridge has a similar problem
537 * and we solve it there by dropping the excess packets.
539 generic_set_tx_event(kring, j);
540 if (generic_netmap_tx_clean(kring)) { /* space now available */
546 slot->flags &= ~(NS_REPORT | NS_BUF_CHANGED);
547 if (unlikely(++j == num_slots))
552 /* Update hwcur to the next slot to transmit. */
556 * Report all new slots as unavailable, even those not sent.
557 * We account for them with with hwreserved, so that
558 * nr_hwreserved =:= cur - nr_hwcur
560 kring->nr_hwavail -= new_slots;
561 kring->nr_hwreserved = k - j;
562 if (kring->nr_hwreserved < 0) {
563 kring->nr_hwreserved += num_slots;
566 IFRATE(rate_ctx.new.txpkt += ntx);
568 if (!kring->nr_hwavail) {
569 /* No more available slots? Set a notification event
570 * on a netmap slot that will be cleaned in the future.
571 * No doublecheck is performed, since txsync() will be
572 * called twice by netmap_poll().
574 generic_set_tx_event(kring, j);
576 ND("tx #%d, hwavail = %d", n, kring->nr_hwavail);
579 /* Synchronize the user's view to the kernel view. */
580 ring->avail = kring->nr_hwavail;
581 ring->reserved = kring->nr_hwreserved;
587 * This handler is registered (through netmap_catch_rx())
588 * within the attached network interface
589 * in the RX subsystem, so that every mbuf passed up by
590 * the driver can be stolen to the network stack.
591 * Stolen packets are put in a queue where the
592 * generic_netmap_rxsync() callback can extract them.
594 void generic_rx_handler(struct ifnet *ifp, struct mbuf *m)
596 struct netmap_adapter *na = NA(ifp);
597 struct netmap_generic_adapter *gna = (struct netmap_generic_adapter *)na;
599 u_int rr = 0; // receive ring number
602 /* limit the size of the queue */
603 if (unlikely(mbq_len(&na->rx_rings[rr].rx_queue) > 1024)) {
606 mbq_safe_enqueue(&na->rx_rings[rr].rx_queue, m);
609 if (netmap_generic_mit < 32768) {
610 /* no rx mitigation, pass notification up */
611 netmap_generic_irq(na->ifp, rr, &work_done);
612 IFRATE(rate_ctx.new.rxirq++);
614 /* same as send combining, filter notification if there is a
615 * pending timer, otherwise pass it up and start a timer.
617 if (likely(netmap_mitigation_active(gna))) {
618 /* Record that there is some pending work. */
619 gna->mit_pending = 1;
621 netmap_generic_irq(na->ifp, rr, &work_done);
622 IFRATE(rate_ctx.new.rxirq++);
623 netmap_mitigation_start(gna);
629 * generic_netmap_rxsync() extracts mbufs from the queue filled by
630 * generic_netmap_rx_handler() and puts their content in the netmap
632 * Access must be protected because the rx handler is asynchronous,
635 generic_netmap_rxsync(struct netmap_adapter *na, u_int ring_nr, int flags)
637 struct netmap_kring *kring = &na->rx_rings[ring_nr];
638 struct netmap_ring *ring = kring->ring;
639 u_int j, n, lim = kring->nkr_num_slots - 1;
640 int force_update = (flags & NAF_FORCE_READ) || kring->nr_kflags & NKR_PENDINTR;
641 u_int k, resvd = ring->reserved;
644 return netmap_ring_reinit(kring);
646 /* Import newly received packets into the netmap ring. */
647 if (netmap_no_pendintr || force_update) {
648 uint16_t slot_flags = kring->nkr_slot_flags;
652 j = kring->nr_ntc; /* first empty slot in the receive ring */
653 /* extract buffers from the rx queue, stop at most one
654 * slot before nr_hwcur (index k)
656 k = (kring->nr_hwcur) ? kring->nr_hwcur-1 : lim;
659 void *addr = NMB(&ring->slot[j]);
661 if (addr == netmap_buffer_base) { /* Bad buffer */
662 return netmap_ring_reinit(kring);
665 * Call the locked version of the function.
666 * XXX Ideally we could grab a batch of mbufs at once,
667 * by changing rx_queue into a ring.
669 m = mbq_safe_dequeue(&kring->rx_queue);
673 m_copydata(m, 0, len, addr);
674 ring->slot[j].len = len;
675 ring->slot[j].flags = slot_flags;
677 if (unlikely(j++ == lim))
683 kring->nr_hwavail += n;
684 IFRATE(rate_ctx.new.rxpkt += n);
686 kring->nr_kflags &= ~NKR_PENDINTR;
689 // XXX should we invert the order ?
690 /* Skip past packets that userspace has released */
694 if (resvd + ring->avail >= lim + 1) {
695 D("XXX invalid reserve/avail %d %d", resvd, ring->avail);
696 ring->reserved = resvd = 0; // XXX panic...
698 k = (k >= resvd) ? k - resvd : k + lim + 1 - resvd;
701 /* Userspace has released some packets. */
702 for (n = 0; j != k; n++) {
703 struct netmap_slot *slot = &ring->slot[j];
705 slot->flags &= ~NS_BUF_CHANGED;
706 if (unlikely(j++ == lim))
709 kring->nr_hwavail -= n;
712 /* Tell userspace that there are new packets. */
713 ring->avail = kring->nr_hwavail - resvd;
714 IFRATE(rate_ctx.new.rxsync++);
720 generic_netmap_dtor(struct netmap_adapter *na)
722 struct ifnet *ifp = na->ifp;
723 struct netmap_generic_adapter *gna = (struct netmap_generic_adapter*)na;
724 struct netmap_adapter *prev_na = gna->prev;
726 if (prev_na != NULL) {
727 D("Released generic NA %p", gna);
731 netmap_adapter_put(prev_na);
735 D("Restored native NA %p", prev_na);
741 * generic_netmap_attach() makes it possible to use netmap on
742 * a device without native netmap support.
743 * This is less performant than native support but potentially
744 * faster than raw sockets or similar schemes.
746 * In this "emulated" mode, netmap rings do not necessarily
747 * have the same size as those in the NIC. We use a default
748 * value and possibly override it if the OS has ways to fetch the
749 * actual configuration.
752 generic_netmap_attach(struct ifnet *ifp)
754 struct netmap_adapter *na;
755 struct netmap_generic_adapter *gna;
757 u_int num_tx_desc, num_rx_desc;
759 num_tx_desc = num_rx_desc = netmap_generic_ringsize; /* starting point */
761 generic_find_num_desc(ifp, &num_tx_desc, &num_rx_desc);
762 ND("Netmap ring size: TX = %d, RX = %d", num_tx_desc, num_rx_desc);
764 gna = kmalloc(sizeof(*gna), M_DEVBUF, M_NOWAIT | M_ZERO);
766 D("no memory on attach, give up");
769 na = (struct netmap_adapter *)gna;
771 na->num_tx_desc = num_tx_desc;
772 na->num_rx_desc = num_rx_desc;
773 na->nm_register = &generic_netmap_register;
774 na->nm_txsync = &generic_netmap_txsync;
775 na->nm_rxsync = &generic_netmap_rxsync;
776 na->nm_dtor = &generic_netmap_dtor;
777 /* when using generic, IFCAP_NETMAP is set so we force
778 * NAF_SKIP_INTR to use the regular interrupt handler
780 na->na_flags = NAF_SKIP_INTR;
782 ND("[GNA] num_tx_queues(%d), real_num_tx_queues(%d), len(%lu)",
783 ifp->num_tx_queues, ifp->real_num_tx_queues,
785 ND("[GNA] num_rx_queues(%d), real_num_rx_queues(%d)",
786 ifp->num_rx_queues, ifp->real_num_rx_queues);
788 generic_find_num_queues(ifp, &na->num_tx_rings, &na->num_rx_rings);
790 retval = netmap_attach_common(na);
792 kfree(gna, M_DEVBUF);