2 * Copyright (C) 2013-2014 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.
65 #include <sys/cdefs.h> /* prerequisite */
66 __FBSDID("$FreeBSD$");
68 #include <sys/types.h>
69 #include <sys/errno.h>
70 #include <sys/malloc.h>
71 #include <sys/lock.h> /* PROT_EXEC */
72 #include <sys/rwlock.h>
73 #include <sys/socket.h> /* sockaddrs */
74 #include <sys/selinfo.h>
76 #include <net/if_var.h>
77 #include <machine/bus.h> /* bus_dmamap_* in netmap_kern.h */
79 // XXX temporary - D() defined here
80 #include <net/netmap.h>
81 #include <dev/netmap/netmap_kern.h>
82 #include <dev/netmap/netmap_mem2.h>
84 #define rtnl_lock() ND("rtnl_lock called")
85 #define rtnl_unlock() ND("rtnl_unlock called")
86 #define MBUF_TXQ(m) ((m)->m_pkthdr.flowid)
87 #define MBUF_RXQ(m) ((m)->m_pkthdr.flowid)
91 * FreeBSD mbuf allocator/deallocator in emulation mode:
93 * We allocate EXT_PACKET mbuf+clusters, but need to set M_NOFREE
94 * so that the destructor, if invoked, will not free the packet.
95 * In principle we should set the destructor only on demand,
96 * but since there might be a race we better do it on allocation.
97 * As a consequence, we also need to set the destructor or we
105 /* mbuf destructor, also need to change the type to EXT_EXTREF,
106 * add an M_NOFREE flag, and then clear the flag and
107 * chain into uma_zfree(zone_pack, mf)
108 * (or reinstall the buffer ?)
110 #define SET_MBUF_DESTRUCTOR(m, fn) do { \
111 (m)->m_ext.ext_free = (void *)fn; \
112 (m)->m_ext.ext_type = EXT_EXTREF; \
116 netmap_default_mbuf_destructor(struct mbuf *m)
118 /* restore original mbuf */
119 m->m_ext.ext_buf = m->m_data = m->m_ext.ext_arg1;
120 m->m_ext.ext_arg1 = NULL;
121 m->m_ext.ext_type = EXT_PACKET;
122 m->m_ext.ext_free = NULL;
123 if (GET_MBUF_REFCNT(m) == 0)
124 SET_MBUF_REFCNT(m, 1);
125 uma_zfree(zone_pack, m);
128 static inline struct mbuf *
129 netmap_get_mbuf(int len)
132 m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR | M_NOFREE);
134 m->m_ext.ext_arg1 = m->m_ext.ext_buf; // XXX save
135 m->m_ext.ext_free = (void *)netmap_default_mbuf_destructor;
136 m->m_ext.ext_type = EXT_EXTREF;
137 ND(5, "create m %p refcnt %d", m, GET_MBUF_REFCNT(m));
146 #include "bsd_glue.h"
148 #include <linux/rtnetlink.h> /* rtnl_[un]lock() */
149 #include <linux/ethtool.h> /* struct ethtool_ops, get_ringparam */
150 #include <linux/hrtimer.h>
157 /* Common headers. */
158 #include <net/netmap.h>
159 #include <dev/netmap/netmap_kern.h>
160 #include <dev/netmap/netmap_mem2.h>
164 /* ======================== usage stats =========================== */
170 unsigned long txsync;
174 unsigned long rxsync;
177 struct rate_context {
179 struct timer_list timer;
180 struct rate_stats new;
181 struct rate_stats old;
184 #define RATE_PRINTK(_NAME_) \
185 printk( #_NAME_ " = %lu Hz\n", (cur._NAME_ - ctx->old._NAME_)/RATE_PERIOD);
186 #define RATE_PERIOD 2
187 static void rate_callback(unsigned long arg)
189 struct rate_context * ctx = (struct rate_context *)arg;
190 struct rate_stats cur = ctx->new;
202 r = mod_timer(&ctx->timer, jiffies +
203 msecs_to_jiffies(RATE_PERIOD * 1000));
205 D("[v1000] Error: mod_timer()");
208 static struct rate_context rate_ctx;
210 void generic_rate(int txp, int txs, int txi, int rxp, int rxs, int rxi)
212 if (txp) rate_ctx.new.txpkt++;
213 if (txs) rate_ctx.new.txsync++;
214 if (txi) rate_ctx.new.txirq++;
215 if (rxp) rate_ctx.new.rxpkt++;
216 if (rxs) rate_ctx.new.rxsync++;
217 if (rxi) rate_ctx.new.rxirq++;
225 /* =============== GENERIC NETMAP ADAPTER SUPPORT ================= */
228 * Wrapper used by the generic adapter layer to notify
229 * the poller threads. Differently from netmap_rx_irq(), we check
230 * only NAF_NETMAP_ON instead of NAF_NATIVE_ON to enable the irq.
233 netmap_generic_irq(struct ifnet *ifp, u_int q, u_int *work_done)
235 struct netmap_adapter *na = NA(ifp);
236 if (unlikely(!nm_netmap_on(na)))
239 netmap_common_irq(ifp, q, work_done);
243 /* Enable/disable netmap mode for a generic network interface. */
245 generic_netmap_register(struct netmap_adapter *na, int enable)
247 struct netmap_generic_adapter *gna = (struct netmap_generic_adapter *)na;
256 error = ifp->netdev_ops->ndo_stop(ifp);
260 #endif /* REG_RESET */
262 if (enable) { /* Enable netmap mode. */
263 /* Init the mitigation support on all the rx queues. */
264 gna->mit = malloc(na->num_rx_rings * sizeof(struct nm_generic_mit),
265 M_DEVBUF, M_NOWAIT | M_ZERO);
267 D("mitigation allocation failed");
271 for (r=0; r<na->num_rx_rings; r++)
272 netmap_mitigation_init(&gna->mit[r], r, na);
274 /* Initialize the rx queue, as generic_rx_handler() can
275 * be called as soon as netmap_catch_rx() returns.
277 for (r=0; r<na->num_rx_rings; r++) {
278 mbq_safe_init(&na->rx_rings[r].rx_queue);
282 * Preallocate packet buffers for the tx rings.
284 for (r=0; r<na->num_tx_rings; r++)
285 na->tx_rings[r].tx_pool = NULL;
286 for (r=0; r<na->num_tx_rings; r++) {
287 na->tx_rings[r].tx_pool = malloc(na->num_tx_desc * sizeof(struct mbuf *),
288 M_DEVBUF, M_NOWAIT | M_ZERO);
289 if (!na->tx_rings[r].tx_pool) {
290 D("tx_pool allocation failed");
294 for (i=0; i<na->num_tx_desc; i++)
295 na->tx_rings[r].tx_pool[i] = NULL;
296 for (i=0; i<na->num_tx_desc; i++) {
297 m = netmap_get_mbuf(NETMAP_BUF_SIZE(na));
299 D("tx_pool[%d] allocation failed", i);
303 na->tx_rings[r].tx_pool[i] = m;
307 /* Prepare to intercept incoming traffic. */
308 error = netmap_catch_rx(na, 1);
310 D("netdev_rx_handler_register() failed (%d)", error);
311 goto register_handler;
313 na->na_flags |= NAF_NETMAP_ON;
315 /* Make netmap control the packet steering. */
316 netmap_catch_tx(gna, 1);
321 if (rate_ctx.refcount == 0) {
323 memset(&rate_ctx, 0, sizeof(rate_ctx));
324 setup_timer(&rate_ctx.timer, &rate_callback, (unsigned long)&rate_ctx);
325 if (mod_timer(&rate_ctx.timer, jiffies + msecs_to_jiffies(1500))) {
326 D("Error: mod_timer()");
332 } else if (na->tx_rings[0].tx_pool) {
333 /* Disable netmap mode. We enter here only if the previous
334 generic_netmap_register(na, 1) was successfull.
335 If it was not, na->tx_rings[0].tx_pool was set to NULL by the
336 error handling code below. */
339 na->na_flags &= ~NAF_NETMAP_ON;
341 /* Release packet steering control. */
342 netmap_catch_tx(gna, 0);
344 /* Do not intercept packets on the rx path. */
345 netmap_catch_rx(na, 0);
349 /* Free the mbufs going to the netmap rings */
350 for (r=0; r<na->num_rx_rings; r++) {
351 mbq_safe_purge(&na->rx_rings[r].rx_queue);
352 mbq_safe_destroy(&na->rx_rings[r].rx_queue);
355 for (r=0; r<na->num_rx_rings; r++)
356 netmap_mitigation_cleanup(&gna->mit[r]);
357 free(gna->mit, M_DEVBUF);
359 for (r=0; r<na->num_tx_rings; r++) {
360 for (i=0; i<na->num_tx_desc; i++) {
361 m_freem(na->tx_rings[r].tx_pool[i]);
363 free(na->tx_rings[r].tx_pool, M_DEVBUF);
367 if (--rate_ctx.refcount == 0) {
369 del_timer(&rate_ctx.timer);
375 error = ifp->netdev_ops->ndo_open(ifp);
386 for (r=0; r<na->num_tx_rings; r++) {
387 if (na->tx_rings[r].tx_pool == NULL)
389 for (i=0; i<na->num_tx_desc; i++)
390 if (na->tx_rings[r].tx_pool[i])
391 m_freem(na->tx_rings[r].tx_pool[i]);
392 free(na->tx_rings[r].tx_pool, M_DEVBUF);
393 na->tx_rings[r].tx_pool = NULL;
395 for (r=0; r<na->num_rx_rings; r++) {
396 netmap_mitigation_cleanup(&gna->mit[r]);
397 mbq_safe_destroy(&na->rx_rings[r].rx_queue);
399 free(gna->mit, M_DEVBUF);
406 * Callback invoked when the device driver frees an mbuf used
407 * by netmap to transmit a packet. This usually happens when
408 * the NIC notifies the driver that transmission is completed.
411 generic_mbuf_destructor(struct mbuf *m)
413 netmap_generic_irq(MBUF_IFP(m), MBUF_TXQ(m), NULL);
416 RD(5, "Tx irq (%p) queue %d index %d" , m, MBUF_TXQ(m), (int)(uintptr_t)m->m_ext.ext_arg1);
417 netmap_default_mbuf_destructor(m);
418 #endif /* __FreeBSD__ */
419 IFRATE(rate_ctx.new.txirq++);
422 extern int netmap_adaptive_io;
424 /* Record completed transmissions and update hwtail.
426 * The oldest tx buffer not yet completed is at nr_hwtail + 1,
427 * nr_hwcur is the first unsent buffer.
430 generic_netmap_tx_clean(struct netmap_kring *kring)
432 u_int const lim = kring->nkr_num_slots - 1;
433 u_int nm_i = nm_next(kring->nr_hwtail, lim);
434 u_int hwcur = kring->nr_hwcur;
436 struct mbuf **tx_pool = kring->tx_pool;
438 while (nm_i != hwcur) { /* buffers not completed */
439 struct mbuf *m = tx_pool[nm_i];
441 if (unlikely(m == NULL)) {
442 /* this is done, try to replenish the entry */
443 tx_pool[nm_i] = m = netmap_get_mbuf(NETMAP_BUF_SIZE(kring->na));
444 if (unlikely(m == NULL)) {
445 D("mbuf allocation failed, XXX error");
446 // XXX how do we proceed ? break ?
449 } else if (GET_MBUF_REFCNT(m) != 1) {
450 break; /* This mbuf is still busy: its refcnt is 2. */
453 nm_i = nm_next(nm_i, lim);
454 #if 0 /* rate adaptation */
455 if (netmap_adaptive_io > 1) {
456 if (n >= netmap_adaptive_io)
458 } else if (netmap_adaptive_io) {
459 /* if hwcur - nm_i < lim/8 do an early break
460 * so we prevent the sender from stalling. See CVT.
463 if (hwcur - nm_i < lim/2)
466 if (hwcur + lim + 1 - nm_i < lim/2)
472 kring->nr_hwtail = nm_prev(nm_i, lim);
473 ND("tx completed [%d] -> hwtail %d", n, kring->nr_hwtail);
480 * We have pending packets in the driver between nr_hwtail +1 and hwcur.
481 * Compute a position in the middle, to be used to generate
485 generic_tx_event_middle(struct netmap_kring *kring, u_int hwcur)
487 u_int n = kring->nkr_num_slots;
488 u_int ntc = nm_next(kring->nr_hwtail, n-1);
492 e = (hwcur + ntc) / 2;
493 } else { /* wrap around */
494 e = (hwcur + n + ntc) / 2;
500 if (unlikely(e >= n)) {
501 D("This cannot happen");
509 * We have pending packets in the driver between nr_hwtail+1 and hwcur.
510 * Schedule a notification approximately in the middle of the two.
511 * There is a race but this is only called within txsync which does
515 generic_set_tx_event(struct netmap_kring *kring, u_int hwcur)
520 if (nm_next(kring->nr_hwtail, kring->nkr_num_slots -1) == hwcur) {
521 return; /* all buffers are free */
523 e = generic_tx_event_middle(kring, hwcur);
525 m = kring->tx_pool[e];
526 ND(5, "Request Event at %d mbuf %p refcnt %d", e, m, m ? GET_MBUF_REFCNT(m) : -2 );
528 /* This can happen if there is already an event on the netmap
529 slot 'e': There is nothing to do. */
532 kring->tx_pool[e] = NULL;
533 SET_MBUF_DESTRUCTOR(m, generic_mbuf_destructor);
536 /* Decrement the refcount an free it if we have the last one. */
543 * generic_netmap_txsync() transforms netmap buffers into mbufs
544 * and passes them to the standard device driver
545 * (ndo_start_xmit() or ifp->if_transmit() ).
546 * On linux this is not done directly, but using dev_queue_xmit(),
547 * since it implements the TX flow control (and takes some locks).
550 generic_netmap_txsync(struct netmap_kring *kring, int flags)
552 struct netmap_adapter *na = kring->na;
553 struct ifnet *ifp = na->ifp;
554 struct netmap_ring *ring = kring->ring;
555 u_int nm_i; /* index into the netmap ring */ // j
556 u_int const lim = kring->nkr_num_slots - 1;
557 u_int const head = kring->rhead;
558 u_int ring_nr = kring->ring_id;
560 IFRATE(rate_ctx.new.txsync++);
562 // TODO: handle the case of mbuf allocation failure
567 * First part: process new packets to send.
569 nm_i = kring->nr_hwcur;
570 if (nm_i != head) { /* we have new packets to send */
571 while (nm_i != head) {
572 struct netmap_slot *slot = &ring->slot[nm_i];
573 u_int len = slot->len;
574 void *addr = NMB(na, slot);
576 /* device-specific */
580 NM_CHECK_ADDR_LEN(na, addr, len);
582 /* Tale a mbuf from the tx pool and copy in the user packet. */
583 m = kring->tx_pool[nm_i];
585 RD(5, "This should never happen");
586 kring->tx_pool[nm_i] = m = netmap_get_mbuf(NETMAP_BUF_SIZE(na));
587 if (unlikely(m == NULL)) {
588 D("mbuf allocation failed");
592 /* XXX we should ask notifications when NS_REPORT is set,
593 * or roughly every half frame. We can optimize this
594 * by lazily requesting notifications only when a
595 * transmission fails. Probably the best way is to
596 * break on failures and set notifications when
597 * ring->cur == ring->tail || nm_i != cur
599 tx_ret = generic_xmit_frame(ifp, m, addr, len, ring_nr);
600 if (unlikely(tx_ret)) {
601 ND(5, "start_xmit failed: err %d [nm_i %u, head %u, hwtail %u]",
602 tx_ret, nm_i, head, kring->nr_hwtail);
604 * No room for this mbuf in the device driver.
605 * Request a notification FOR A PREVIOUS MBUF,
606 * then call generic_netmap_tx_clean(kring) to do the
607 * double check and see if we can free more buffers.
608 * If there is space continue, else break;
609 * NOTE: the double check is necessary if the problem
610 * occurs in the txsync call after selrecord().
611 * Also, we need some way to tell the caller that not
612 * all buffers were queued onto the device (this was
613 * not a problem with native netmap driver where space
614 * is preallocated). The bridge has a similar problem
615 * and we solve it there by dropping the excess packets.
617 generic_set_tx_event(kring, nm_i);
618 if (generic_netmap_tx_clean(kring)) { /* space now available */
624 slot->flags &= ~(NS_REPORT | NS_BUF_CHANGED);
625 nm_i = nm_next(nm_i, lim);
626 IFRATE(rate_ctx.new.txpkt ++);
629 /* Update hwcur to the next slot to transmit. */
630 kring->nr_hwcur = nm_i; /* not head, we could break early */
634 * Second, reclaim completed buffers
636 if (flags & NAF_FORCE_RECLAIM || nm_kr_txempty(kring)) {
637 /* No more available slots? Set a notification event
638 * on a netmap slot that will be cleaned in the future.
639 * No doublecheck is performed, since txsync() will be
640 * called twice by netmap_poll().
642 generic_set_tx_event(kring, nm_i);
644 ND("tx #%d, hwtail = %d", n, kring->nr_hwtail);
646 generic_netmap_tx_clean(kring);
648 nm_txsync_finalize(kring);
655 * This handler is registered (through netmap_catch_rx())
656 * within the attached network interface
657 * in the RX subsystem, so that every mbuf passed up by
658 * the driver can be stolen to the network stack.
659 * Stolen packets are put in a queue where the
660 * generic_netmap_rxsync() callback can extract them.
663 generic_rx_handler(struct ifnet *ifp, struct mbuf *m)
665 struct netmap_adapter *na = NA(ifp);
666 struct netmap_generic_adapter *gna = (struct netmap_generic_adapter *)na;
668 u_int rr = MBUF_RXQ(m); // receive ring number
670 if (rr >= na->num_rx_rings) {
671 rr = rr % na->num_rx_rings; // XXX expensive...
674 /* limit the size of the queue */
675 if (unlikely(mbq_len(&na->rx_rings[rr].rx_queue) > 1024)) {
678 mbq_safe_enqueue(&na->rx_rings[rr].rx_queue, m);
681 if (netmap_generic_mit < 32768) {
682 /* no rx mitigation, pass notification up */
683 netmap_generic_irq(na->ifp, rr, &work_done);
684 IFRATE(rate_ctx.new.rxirq++);
686 /* same as send combining, filter notification if there is a
687 * pending timer, otherwise pass it up and start a timer.
689 if (likely(netmap_mitigation_active(&gna->mit[rr]))) {
690 /* Record that there is some pending work. */
691 gna->mit[rr].mit_pending = 1;
693 netmap_generic_irq(na->ifp, rr, &work_done);
694 IFRATE(rate_ctx.new.rxirq++);
695 netmap_mitigation_start(&gna->mit[rr]);
701 * generic_netmap_rxsync() extracts mbufs from the queue filled by
702 * generic_netmap_rx_handler() and puts their content in the netmap
704 * Access must be protected because the rx handler is asynchronous,
707 generic_netmap_rxsync(struct netmap_kring *kring, int flags)
709 struct netmap_ring *ring = kring->ring;
710 struct netmap_adapter *na = kring->na;
711 u_int nm_i; /* index into the netmap ring */ //j,
713 u_int const lim = kring->nkr_num_slots - 1;
714 u_int const head = nm_rxsync_prologue(kring);
715 int force_update = (flags & NAF_FORCE_READ) || kring->nr_kflags & NKR_PENDINTR;
718 return netmap_ring_reinit(kring);
721 * First part: import newly received packets.
723 if (netmap_no_pendintr || force_update) {
724 /* extract buffers from the rx queue, stop at most one
725 * slot before nr_hwcur (stop_i)
727 uint16_t slot_flags = kring->nkr_slot_flags;
728 u_int stop_i = nm_prev(kring->nr_hwcur, lim);
730 nm_i = kring->nr_hwtail; /* first empty slot in the receive ring */
731 for (n = 0; nm_i != stop_i; n++) {
733 void *addr = NMB(na, &ring->slot[nm_i]);
736 /* we only check the address here on generic rx rings */
737 if (addr == NETMAP_BUF_BASE(na)) { /* Bad buffer */
738 return netmap_ring_reinit(kring);
741 * Call the locked version of the function.
742 * XXX Ideally we could grab a batch of mbufs at once
743 * and save some locking overhead.
745 m = mbq_safe_dequeue(&kring->rx_queue);
746 if (!m) /* no more data */
749 m_copydata(m, 0, len, addr);
750 ring->slot[nm_i].len = len;
751 ring->slot[nm_i].flags = slot_flags;
753 nm_i = nm_next(nm_i, lim);
756 kring->nr_hwtail = nm_i;
757 IFRATE(rate_ctx.new.rxpkt += n);
759 kring->nr_kflags &= ~NKR_PENDINTR;
762 // XXX should we invert the order ?
764 * Second part: skip past packets that userspace has released.
766 nm_i = kring->nr_hwcur;
768 /* Userspace has released some packets. */
769 for (n = 0; nm_i != head; n++) {
770 struct netmap_slot *slot = &ring->slot[nm_i];
772 slot->flags &= ~NS_BUF_CHANGED;
773 nm_i = nm_next(nm_i, lim);
775 kring->nr_hwcur = head;
777 /* tell userspace that there might be new packets. */
778 nm_rxsync_finalize(kring);
779 IFRATE(rate_ctx.new.rxsync++);
785 generic_netmap_dtor(struct netmap_adapter *na)
787 struct ifnet *ifp = na->ifp;
788 struct netmap_generic_adapter *gna = (struct netmap_generic_adapter*)na;
789 struct netmap_adapter *prev_na = gna->prev;
791 if (prev_na != NULL) {
792 D("Released generic NA %p", gna);
794 netmap_adapter_put(prev_na);
798 D("Restored native NA %p", prev_na);
804 * generic_netmap_attach() makes it possible to use netmap on
805 * a device without native netmap support.
806 * This is less performant than native support but potentially
807 * faster than raw sockets or similar schemes.
809 * In this "emulated" mode, netmap rings do not necessarily
810 * have the same size as those in the NIC. We use a default
811 * value and possibly override it if the OS has ways to fetch the
812 * actual configuration.
815 generic_netmap_attach(struct ifnet *ifp)
817 struct netmap_adapter *na;
818 struct netmap_generic_adapter *gna;
820 u_int num_tx_desc, num_rx_desc;
822 num_tx_desc = num_rx_desc = netmap_generic_ringsize; /* starting point */
824 generic_find_num_desc(ifp, &num_tx_desc, &num_rx_desc); /* ignore errors */
825 ND("Netmap ring size: TX = %d, RX = %d", num_tx_desc, num_rx_desc);
826 if (num_tx_desc == 0 || num_rx_desc == 0) {
827 D("Device has no hw slots (tx %u, rx %u)", num_tx_desc, num_rx_desc);
831 gna = malloc(sizeof(*gna), M_DEVBUF, M_NOWAIT | M_ZERO);
833 D("no memory on attach, give up");
836 na = (struct netmap_adapter *)gna;
838 na->num_tx_desc = num_tx_desc;
839 na->num_rx_desc = num_rx_desc;
840 na->nm_register = &generic_netmap_register;
841 na->nm_txsync = &generic_netmap_txsync;
842 na->nm_rxsync = &generic_netmap_rxsync;
843 na->nm_dtor = &generic_netmap_dtor;
844 /* when using generic, NAF_NETMAP_ON is set so we force
845 * NAF_SKIP_INTR to use the regular interrupt handler
847 na->na_flags = NAF_SKIP_INTR | NAF_HOST_RINGS;
849 ND("[GNA] num_tx_queues(%d), real_num_tx_queues(%d), len(%lu)",
850 ifp->num_tx_queues, ifp->real_num_tx_queues,
852 ND("[GNA] num_rx_queues(%d), real_num_rx_queues(%d)",
853 ifp->num_rx_queues, ifp->real_num_rx_queues);
855 generic_find_num_queues(ifp, &na->num_tx_rings, &na->num_rx_rings);
857 retval = netmap_attach_common(na);