xref: /freebsd/sys/dev/netmap/netmap_kern.h (revision 17885a7bfde9d164e45a9833bb172215c55739f9)
1 /*
2  * Copyright (C) 2011-2014 Matteo Landi, Luigi Rizzo. All rights reserved.
3  * Copyright (C) 2013-2014 Universita` di Pisa. All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  *   1. Redistributions of source code must retain the above copyright
9  *      notice, this list of conditions and the following disclaimer.
10  *   2. Redistributions in binary form must reproduce the above copyright
11  *      notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 /*
28  * $FreeBSD$
29  *
30  * The header contains the definitions of constants and function
31  * prototypes used only in kernelspace.
32  */
33 
34 #ifndef _NET_NETMAP_KERN_H_
35 #define _NET_NETMAP_KERN_H_
36 
37 #define WITH_VALE	// comment out to disable VALE support
38 
39 #if defined(__FreeBSD__)
40 
41 #define likely(x)	__builtin_expect((long)!!(x), 1L)
42 #define unlikely(x)	__builtin_expect((long)!!(x), 0L)
43 
44 #define	NM_LOCK_T	struct mtx
45 #define	NMG_LOCK_T	struct mtx
46 #define NMG_LOCK_INIT()	mtx_init(&netmap_global_lock, \
47 				"netmap global lock", NULL, MTX_DEF)
48 #define NMG_LOCK_DESTROY()	mtx_destroy(&netmap_global_lock)
49 #define NMG_LOCK()	mtx_lock(&netmap_global_lock)
50 #define NMG_UNLOCK()	mtx_unlock(&netmap_global_lock)
51 #define NMG_LOCK_ASSERT()	mtx_assert(&netmap_global_lock, MA_OWNED)
52 
53 #define	NM_SELINFO_T	struct selinfo
54 #define	MBUF_LEN(m)	((m)->m_pkthdr.len)
55 #define	MBUF_IFP(m)	((m)->m_pkthdr.rcvif)
56 #define	NM_SEND_UP(ifp, m)	((NA(ifp))->if_input)(ifp, m)
57 
58 #define NM_ATOMIC_T	volatile int	// XXX ?
59 /* atomic operations */
60 #include <machine/atomic.h>
61 #define NM_ATOMIC_TEST_AND_SET(p)       (!atomic_cmpset_acq_int((p), 0, 1))
62 #define NM_ATOMIC_CLEAR(p)              atomic_store_rel_int((p), 0)
63 
64 
65 MALLOC_DECLARE(M_NETMAP);
66 
67 // XXX linux struct, not used in FreeBSD
68 struct net_device_ops {
69 };
70 struct hrtimer {
71 };
72 
73 #elif defined (linux)
74 
75 #define	NM_LOCK_T	safe_spinlock_t	// see bsd_glue.h
76 #define	NM_SELINFO_T	wait_queue_head_t
77 #define	MBUF_LEN(m)	((m)->len)
78 #define	MBUF_IFP(m)	((m)->dev)
79 #define	NM_SEND_UP(ifp, m)  \
80                         do { \
81                             m->priority = NM_MAGIC_PRIORITY; \
82                             netif_rx(m); \
83                         } while (0)
84 
85 #define NM_ATOMIC_T	volatile long unsigned int
86 
87 // XXX a mtx would suffice here too 20130404 gl
88 #define NMG_LOCK_T		struct semaphore
89 #define NMG_LOCK_INIT()		sema_init(&netmap_global_lock, 1)
90 #define NMG_LOCK_DESTROY()
91 #define NMG_LOCK()		down(&netmap_global_lock)
92 #define NMG_UNLOCK()		up(&netmap_global_lock)
93 #define NMG_LOCK_ASSERT()	//	XXX to be completed
94 
95 #ifndef DEV_NETMAP
96 #define DEV_NETMAP
97 #endif /* DEV_NETMAP */
98 
99 /*
100  * IFCAP_NETMAP goes into net_device's priv_flags (if_capenable).
101  * This was 16 bits up to linux 2.6.36, so we need a 16 bit value on older
102  * platforms and tolerate the clash with IFF_DYNAMIC and IFF_BRIDGE_PORT.
103  * For the 32-bit value, 0x100000 has no clashes until at least 3.5.1
104  */
105 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,37)
106 #define IFCAP_NETMAP	0x8000
107 #else
108 #define IFCAP_NETMAP	0x200000
109 #endif
110 
111 #elif defined (__APPLE__)
112 
113 #warning apple support is incomplete.
114 #define likely(x)	__builtin_expect(!!(x), 1)
115 #define unlikely(x)	__builtin_expect(!!(x), 0)
116 #define	NM_LOCK_T	IOLock *
117 #define	NM_SELINFO_T	struct selinfo
118 #define	MBUF_LEN(m)	((m)->m_pkthdr.len)
119 #define	NM_SEND_UP(ifp, m)	((ifp)->if_input)(ifp, m)
120 
121 #else
122 
123 #error unsupported platform
124 
125 #endif /* end - platform-specific code */
126 
127 #define ND(format, ...)
128 #define D(format, ...)						\
129 	do {							\
130 		struct timeval __xxts;				\
131 		microtime(&__xxts);				\
132 		printf("%03d.%06d [%4d] %-25s " format "\n",	\
133 		(int)__xxts.tv_sec % 1000, (int)__xxts.tv_usec,	\
134 		__LINE__, __FUNCTION__, ##__VA_ARGS__);		\
135 	} while (0)
136 
137 /* rate limited, lps indicates how many per second */
138 #define RD(lps, format, ...)					\
139 	do {							\
140 		static int t0, __cnt;				\
141 		if (t0 != time_second) {			\
142 			t0 = time_second;			\
143 			__cnt = 0;				\
144 		}						\
145 		if (__cnt++ < lps)				\
146 			D(format, ##__VA_ARGS__);		\
147 	} while (0)
148 
149 struct netmap_adapter;
150 struct nm_bdg_fwd;
151 struct nm_bridge;
152 struct netmap_priv_d;
153 
154 const char *nm_dump_buf(char *p, int len, int lim, char *dst);
155 
156 #include "netmap_mbq.h"
157 
158 extern NMG_LOCK_T	netmap_global_lock;
159 
160 /*
161  * private, kernel view of a ring. Keeps track of the status of
162  * a ring across system calls.
163  *
164  *	nr_hwcur	index of the next buffer to refill.
165  *			It corresponds to ring->head
166  *			at the time the system call returns.
167  *
168  *	nr_hwtail	index of the first buffer owned by the kernel.
169  *			On RX, hwcur->hwtail are receive buffers
170  *			not yet released. hwcur is advanced following
171  *			ring->head, hwtail is advanced on incoming packets,
172  *			and a wakeup is generated when hwtail passes ring->cur
173  *			    On TX, hwcur->rcur have been filled by the sender
174  *			but not sent yet to the NIC; rcur->hwtail are available
175  *			for new transmissions, and hwtail->hwcur-1 are pending
176  *			transmissions not yet acknowledged.
177  *
178  * The indexes in the NIC and netmap rings are offset by nkr_hwofs slots.
179  * This is so that, on a reset, buffers owned by userspace are not
180  * modified by the kernel. In particular:
181  * RX rings: the next empty buffer (hwtail + hwofs) coincides with
182  * 	the next empty buffer as known by the hardware (next_to_check or so).
183  * TX rings: hwcur + hwofs coincides with next_to_send
184  *
185  * Clients cannot issue concurrent syscall on a ring. The system
186  * detects this and reports an error using two flags,
187  * NKR_WBUSY and NKR_RBUSY
188  * For received packets, slot->flags is set to nkr_slot_flags
189  * so we can provide a proper initial value (e.g. set NS_FORWARD
190  * when operating in 'transparent' mode).
191  *
192  * The following fields are used to implement lock-free copy of packets
193  * from input to output ports in VALE switch:
194  *	nkr_hwlease	buffer after the last one being copied.
195  *			A writer in nm_bdg_flush reserves N buffers
196  *			from nr_hwlease, advances it, then does the
197  *			copy outside the lock.
198  *			In RX rings (used for VALE ports),
199  *			nkr_hwtail <= nkr_hwlease < nkr_hwcur+N-1
200  *			In TX rings (used for NIC or host stack ports)
201  *			nkr_hwcur <= nkr_hwlease < nkr_hwtail
202  *	nkr_leases	array of nkr_num_slots where writers can report
203  *			completion of their block. NR_NOSLOT (~0) indicates
204  *			that the writer has not finished yet
205  *	nkr_lease_idx	index of next free slot in nr_leases, to be assigned
206  *
207  * The kring is manipulated by txsync/rxsync and generic netmap function.
208  *
209  * Concurrent rxsync or txsync on the same ring are prevented through
210  * by nm_kr_lock() which in turn uses nr_busy. This is all we need
211  * for NIC rings, and for TX rings attached to the host stack.
212  *
213  * RX rings attached to the host stack use an mbq (rx_queue) on both
214  * rxsync_from_host() and netmap_transmit(). The mbq is protected
215  * by its internal lock.
216  *
217  * RX rings attached to the VALE switch are accessed by both sender
218  * and receiver. They are protected through the q_lock on the RX ring.
219  */
220 struct netmap_kring {
221 	struct netmap_ring	*ring;
222 
223 	uint32_t	nr_hwcur;
224 	uint32_t	nr_hwtail;
225 
226 	/*
227 	 * Copies of values in user rings, so we do not need to look
228 	 * at the ring (which could be modified). These are set in the
229 	 * *sync_prologue()/finalize() routines.
230 	 */
231 	uint32_t	rhead;
232 	uint32_t	rcur;
233 	uint32_t	rtail;
234 
235 	uint32_t	nr_kflags;	/* private driver flags */
236 #define NKR_PENDINTR	0x1		// Pending interrupt.
237 	uint32_t	nkr_num_slots;
238 
239 	/*
240 	 * On a NIC reset, the NIC ring indexes may be reset but the
241 	 * indexes in the netmap rings remain the same. nkr_hwofs
242 	 * keeps track of the offset between the two.
243 	 */
244 	int32_t		nkr_hwofs;
245 
246 	uint16_t	nkr_slot_flags;	/* initial value for flags */
247 
248 	/* last_reclaim is opaque marker to help reduce the frequency
249 	 * of operations such as reclaiming tx buffers. A possible use
250 	 * is set it to ticks and do the reclaim only once per tick.
251 	 */
252 	uint64_t	last_reclaim;
253 
254 
255 	NM_SELINFO_T	si;		/* poll/select wait queue */
256 	NM_LOCK_T	q_lock;		/* protects kring and ring. */
257 	NM_ATOMIC_T	nr_busy;	/* prevent concurrent syscalls */
258 
259 	struct netmap_adapter *na;
260 
261 	/* The folloiwing fields are for VALE switch support */
262 	struct nm_bdg_fwd *nkr_ft;
263 	uint32_t	*nkr_leases;
264 #define NR_NOSLOT	((uint32_t)~0)	/* used in nkr_*lease* */
265 	uint32_t	nkr_hwlease;
266 	uint32_t	nkr_lease_idx;
267 
268 	volatile int nkr_stopped;	// XXX what for ?
269 
270 	/* support for adapters without native netmap support.
271 	 * On tx rings we preallocate an array of tx buffers
272 	 * (same size as the netmap ring), on rx rings we
273 	 * store incoming packets in a queue.
274 	 * XXX who writes to the rx queue ?
275 	 */
276 	struct mbuf **tx_pool;
277 	// u_int nr_ntc;		/* Emulation of a next-to-clean RX ring pointer. */
278 	struct mbq rx_queue;            /* intercepted rx mbufs. */
279 
280 	uint32_t	ring_id;	/* debugging */
281 	char name[64];			/* diagnostic */
282 
283 } __attribute__((__aligned__(64)));
284 
285 
286 /* return the next index, with wraparound */
287 static inline uint32_t
288 nm_next(uint32_t i, uint32_t lim)
289 {
290 	return unlikely (i == lim) ? 0 : i + 1;
291 }
292 
293 
294 /* return the previous index, with wraparound */
295 static inline uint32_t
296 nm_prev(uint32_t i, uint32_t lim)
297 {
298 	return unlikely (i == 0) ? lim : i - 1;
299 }
300 
301 
302 /*
303  *
304  * Here is the layout for the Rx and Tx rings.
305 
306        RxRING                            TxRING
307 
308       +-----------------+            +-----------------+
309       |                 |            |                 |
310       |XXX free slot XXX|            |XXX free slot XXX|
311       +-----------------+            +-----------------+
312 head->| owned by user   |<-hwcur     | not sent to nic |<-hwcur
313       |                 |            | yet             |
314       +-----------------+            |                 |
315  cur->| available to    |            |                 |
316       | user, not read  |            +-----------------+
317       | yet             |       cur->| (being          |
318       |                 |            |  prepared)      |
319       |                 |            |                 |
320       +-----------------+            +     ------      +
321 tail->|                 |<-hwtail    |                 |<-hwlease
322       | (being          | ...        |                 | ...
323       |  prepared)      | ...        |                 | ...
324       +-----------------+ ...        |                 | ...
325       |                 |<-hwlease   +-----------------+
326       |                 |      tail->|                 |<-hwtail
327       |                 |            |                 |
328       |                 |            |                 |
329       |                 |            |                 |
330       +-----------------+            +-----------------+
331 
332  * The cur/tail (user view) and hwcur/hwtail (kernel view)
333  * are used in the normal operation of the card.
334  *
335  * When a ring is the output of a switch port (Rx ring for
336  * a VALE port, Tx ring for the host stack or NIC), slots
337  * are reserved in blocks through 'hwlease' which points
338  * to the next unused slot.
339  * On an Rx ring, hwlease is always after hwtail,
340  * and completions cause hwtail to advance.
341  * On a Tx ring, hwlease is always between cur and hwtail,
342  * and completions cause cur to advance.
343  *
344  * nm_kr_space() returns the maximum number of slots that
345  * can be assigned.
346  * nm_kr_lease() reserves the required number of buffers,
347  *    advances nkr_hwlease and also returns an entry in
348  *    a circular array where completions should be reported.
349  */
350 
351 
352 
353 enum txrx { NR_RX = 0, NR_TX = 1 };
354 
355 /*
356  * The "struct netmap_adapter" extends the "struct adapter"
357  * (or equivalent) device descriptor.
358  * It contains all base fields needed to support netmap operation.
359  * There are in fact different types of netmap adapters
360  * (native, generic, VALE switch...) so a netmap_adapter is
361  * just the first field in the derived type.
362  */
363 struct netmap_adapter {
364 	/*
365 	 * On linux we do not have a good way to tell if an interface
366 	 * is netmap-capable. So we always use the following trick:
367 	 * NA(ifp) points here, and the first entry (which hopefully
368 	 * always exists and is at least 32 bits) contains a magic
369 	 * value which we can use to detect that the interface is good.
370 	 */
371 	uint32_t magic;
372 	uint32_t na_flags;	/* enabled, and other flags */
373 #define NAF_SKIP_INTR	1	/* use the regular interrupt handler.
374 				 * useful during initialization
375 				 */
376 #define NAF_SW_ONLY	2	/* forward packets only to sw adapter */
377 #define NAF_BDG_MAYSLEEP 4	/* the bridge is allowed to sleep when
378 				 * forwarding packets coming from this
379 				 * interface
380 				 */
381 #define NAF_MEM_OWNER	8	/* the adapter is responsible for the
382 				 * deallocation of the memory allocator
383 				 */
384 #define NAF_NATIVE_ON   16      /* the adapter is native and the attached
385 				 * interface is in netmap mode
386 				 */
387 #define	NAF_NETMAP_ON	32	/* netmap is active (either native or
388 				 * emulated. Where possible (e.g. FreeBSD)
389 				 * IFCAP_NETMAP also mirrors this flag.
390 				 */
391 	int active_fds; /* number of user-space descriptors using this
392 			 interface, which is equal to the number of
393 			 struct netmap_if objs in the mapped region. */
394 
395 	u_int num_rx_rings; /* number of adapter receive rings */
396 	u_int num_tx_rings; /* number of adapter transmit rings */
397 
398 	u_int num_tx_desc; /* number of descriptor in each queue */
399 	u_int num_rx_desc;
400 
401 	/* tx_rings and rx_rings are private but allocated
402 	 * as a contiguous chunk of memory. Each array has
403 	 * N+1 entries, for the adapter queues and for the host queue.
404 	 */
405 	struct netmap_kring *tx_rings; /* array of TX rings. */
406 	struct netmap_kring *rx_rings; /* array of RX rings. */
407 
408 	void *tailroom;		       /* space below the rings array */
409 				       /* (used for leases) */
410 
411 
412 	NM_SELINFO_T tx_si, rx_si;	/* global wait queues */
413 
414 	/* copy of if_qflush and if_transmit pointers, to intercept
415 	 * packets from the network stack when netmap is active.
416 	 */
417 	int     (*if_transmit)(struct ifnet *, struct mbuf *);
418 
419 	/* copy of if_input for netmap_send_up() */
420 	void     (*if_input)(struct ifnet *, struct mbuf *);
421 
422 	/* references to the ifnet and device routines, used by
423 	 * the generic netmap functions.
424 	 */
425 	struct ifnet *ifp; /* adapter is ifp->if_softc */
426 
427 	/*---- callbacks for this netmap adapter -----*/
428 	/*
429 	 * nm_dtor() is the cleanup routine called when destroying
430 	 *	the adapter.
431 	 *
432 	 * nm_register() is called on NIOCREGIF and close() to enter
433 	 *	or exit netmap mode on the NIC
434 	 *
435 	 * nm_txsync() pushes packets to the underlying hw/switch
436 	 *
437 	 * nm_rxsync() collects packets from the underlying hw/switch
438 	 *
439 	 * nm_config() returns configuration information from the OS
440 	 *
441 	 * nm_krings_create() XXX
442 	 *
443 	 * nm_krings_delete() XXX
444 	 *
445 	 * nm_notify() is used to act after data have become available.
446 	 *	For hw devices this is typically a selwakeup(),
447 	 *	but for NIC/host ports attached to a switch (or vice-versa)
448 	 *	we also need to invoke the 'txsync' code downstream.
449 	 */
450 
451 	/* private cleanup */
452 	void (*nm_dtor)(struct netmap_adapter *);
453 
454 	int (*nm_register)(struct netmap_adapter *, int onoff);
455 
456 	int (*nm_txsync)(struct netmap_adapter *, u_int ring, int flags);
457 	int (*nm_rxsync)(struct netmap_adapter *, u_int ring, int flags);
458 #define NAF_FORCE_READ    1
459 #define NAF_FORCE_RECLAIM 2
460 	/* return configuration information */
461 	int (*nm_config)(struct netmap_adapter *,
462 		u_int *txr, u_int *txd, u_int *rxr, u_int *rxd);
463 	int (*nm_krings_create)(struct netmap_adapter *);
464 	void (*nm_krings_delete)(struct netmap_adapter *);
465 	int (*nm_notify)(struct netmap_adapter *,
466 		u_int ring, enum txrx, int flags);
467 #define NAF_GLOBAL_NOTIFY 4
468 #define NAF_DISABLE_NOTIFY 8
469 
470 	/* standard refcount to control the lifetime of the adapter
471 	 * (it should be equal to the lifetime of the corresponding ifp)
472 	 */
473 	int na_refcount;
474 
475 	/* memory allocator (opaque)
476 	 * We also cache a pointer to the lut_entry for translating
477 	 * buffer addresses, and the total number of buffers.
478 	 */
479  	struct netmap_mem_d *nm_mem;
480 	struct lut_entry *na_lut;
481 	uint32_t na_lut_objtotal;	/* max buffer index */
482 
483 	/* used internally. If non-null, the interface cannot be bound
484 	 * from userspace
485 	 */
486 	void *na_private;
487 };
488 
489 
490 /*
491  * If the NIC is owned by the kernel
492  * (i.e., bridge), neither another bridge nor user can use it;
493  * if the NIC is owned by a user, only users can share it.
494  * Evaluation must be done under NMG_LOCK().
495  */
496 #define NETMAP_OWNED_BY_KERN(na)	(na->na_private)
497 #define NETMAP_OWNED_BY_ANY(na) \
498 	(NETMAP_OWNED_BY_KERN(na) || (na->active_fds > 0))
499 
500 
501 /*
502  * derived netmap adapters for various types of ports
503  */
504 struct netmap_vp_adapter {	/* VALE software port */
505 	struct netmap_adapter up;
506 
507 	/*
508 	 * Bridge support:
509 	 *
510 	 * bdg_port is the port number used in the bridge;
511 	 * na_bdg points to the bridge this NA is attached to.
512 	 */
513 	int bdg_port;
514 	struct nm_bridge *na_bdg;
515 	int retry;
516 
517 	u_int offset;   /* Offset of ethernet header for each packet. */
518 };
519 
520 
521 struct netmap_hw_adapter {	/* physical device */
522 	struct netmap_adapter up;
523 
524 	struct net_device_ops nm_ndo;	// XXX linux only
525 };
526 
527 
528 struct netmap_generic_adapter {	/* emulated device */
529 	struct netmap_hw_adapter up;
530 
531 	/* Pointer to a previously used netmap adapter. */
532 	struct netmap_adapter *prev;
533 
534 	/* generic netmap adapters support:
535 	 * a net_device_ops struct overrides ndo_select_queue(),
536 	 * save_if_input saves the if_input hook (FreeBSD),
537 	 * mit_timer and mit_pending implement rx interrupt mitigation,
538 	 */
539 	struct net_device_ops generic_ndo;
540 	void (*save_if_input)(struct ifnet *, struct mbuf *);
541 
542 	struct hrtimer mit_timer;
543 	int mit_pending;
544 #ifdef linux
545         netdev_tx_t (*save_start_xmit)(struct mbuf *, struct ifnet *);
546 #endif
547 };
548 
549 #ifdef WITH_VALE
550 
551 /*
552  * Bridge wrapper for non VALE ports attached to a VALE switch.
553  *
554  * The real device must already have its own netmap adapter (hwna).
555  * The bridge wrapper and the hwna adapter share the same set of
556  * netmap rings and buffers, but they have two separate sets of
557  * krings descriptors, with tx/rx meanings swapped:
558  *
559  *                                  netmap
560  *           bwrap     krings       rings      krings      hwna
561  *         +------+   +------+     +-----+    +------+   +------+
562  *         |tx_rings->|      |\   /|     |----|      |<-tx_rings|
563  *         |      |   +------+ \ / +-----+    +------+   |      |
564  *         |      |             X                        |      |
565  *         |      |            / \                       |      |
566  *         |      |   +------+/   \+-----+    +------+   |      |
567  *         |rx_rings->|      |     |     |----|      |<-rx_rings|
568  *         |      |   +------+     +-----+    +------+   |      |
569  *         +------+                                      +------+
570  *
571  * - packets coming from the bridge go to the brwap rx rings,
572  *   which are also the hwna tx rings.  The bwrap notify callback
573  *   will then complete the hwna tx (see netmap_bwrap_notify).
574  *
575  * - packets coming from the outside go to the hwna rx rings,
576  *   which are also the bwrap tx rings.  The (overwritten) hwna
577  *   notify method will then complete the bridge tx
578  *   (see netmap_bwrap_intr_notify).
579  *
580  *   The bridge wrapper may optionally connect the hwna 'host' rings
581  *   to the bridge. This is done by using a second port in the
582  *   bridge and connecting it to the 'host' netmap_vp_adapter
583  *   contained in the netmap_bwrap_adapter. The brwap host adapter
584  *   cross-links the hwna host rings in the same way as shown above.
585  *
586  * - packets coming from the bridge and directed to the host stack
587  *   are handled by the bwrap host notify callback
588  *   (see netmap_bwrap_host_notify)
589  *
590  * - packets coming from the host stack are still handled by the
591  *   overwritten hwna notify callback (netmap_bwrap_intr_notify),
592  *   but are diverted to the host adapter depending on the ring number.
593  *
594  */
595 struct netmap_bwrap_adapter {
596 	struct netmap_vp_adapter up;
597 	struct netmap_vp_adapter host;  /* for host rings */
598 	struct netmap_adapter *hwna;	/* the underlying device */
599 
600 	/* backup of the hwna notify callback */
601 	int (*save_notify)(struct netmap_adapter *,
602 			u_int ring, enum txrx, int flags);
603 
604 	/*
605 	 * When we attach a physical interface to the bridge, we
606 	 * allow the controlling process to terminate, so we need
607 	 * a place to store the netmap_priv_d data structure.
608 	 * This is only done when physical interfaces
609 	 * are attached to a bridge.
610 	 */
611 	struct netmap_priv_d *na_kpriv;
612 };
613 
614 
615 #endif /* WITH_VALE */
616 
617 
618 /* return slots reserved to rx clients; used in drivers */
619 static inline uint32_t
620 nm_kr_rxspace(struct netmap_kring *k)
621 {
622 	int space = k->nr_hwtail - k->nr_hwcur;
623 	if (space < 0)
624 		space += k->nkr_num_slots;
625 	ND("preserving %d rx slots %d -> %d", space, k->nr_hwcur, k->nr_hwtail);
626 
627 	return space;
628 }
629 
630 
631 /* True if no space in the tx ring. only valid after txsync_prologue */
632 static inline int
633 nm_kr_txempty(struct netmap_kring *kring)
634 {
635 	return kring->rcur == kring->nr_hwtail;
636 }
637 
638 
639 /*
640  * protect against multiple threads using the same ring.
641  * also check that the ring has not been stopped.
642  * We only care for 0 or !=0 as a return code.
643  */
644 #define NM_KR_BUSY	1
645 #define NM_KR_STOPPED	2
646 
647 
648 static __inline void nm_kr_put(struct netmap_kring *kr)
649 {
650 	NM_ATOMIC_CLEAR(&kr->nr_busy);
651 }
652 
653 
654 static __inline int nm_kr_tryget(struct netmap_kring *kr)
655 {
656 	/* check a first time without taking the lock
657 	 * to avoid starvation for nm_kr_get()
658 	 */
659 	if (unlikely(kr->nkr_stopped)) {
660 		ND("ring %p stopped (%d)", kr, kr->nkr_stopped);
661 		return NM_KR_STOPPED;
662 	}
663 	if (unlikely(NM_ATOMIC_TEST_AND_SET(&kr->nr_busy)))
664 		return NM_KR_BUSY;
665 	/* check a second time with lock held */
666 	if (unlikely(kr->nkr_stopped)) {
667 		ND("ring %p stopped (%d)", kr, kr->nkr_stopped);
668 		nm_kr_put(kr);
669 		return NM_KR_STOPPED;
670 	}
671 	return 0;
672 }
673 
674 
675 /*
676  * The following functions are used by individual drivers to
677  * support netmap operation.
678  *
679  * netmap_attach() initializes a struct netmap_adapter, allocating the
680  * 	struct netmap_ring's and the struct selinfo.
681  *
682  * netmap_detach() frees the memory allocated by netmap_attach().
683  *
684  * netmap_transmit() replaces the if_transmit routine of the interface,
685  *	and is used to intercept packets coming from the stack.
686  *
687  * netmap_load_map/netmap_reload_map are helper routines to set/reset
688  *	the dmamap for a packet buffer
689  *
690  * netmap_reset() is a helper routine to be called in the driver
691  *	when reinitializing a ring.
692  */
693 int netmap_attach(struct netmap_adapter *);
694 int netmap_attach_common(struct netmap_adapter *);
695 void netmap_detach_common(struct netmap_adapter *na);
696 void netmap_detach(struct ifnet *);
697 int netmap_transmit(struct ifnet *, struct mbuf *);
698 struct netmap_slot *netmap_reset(struct netmap_adapter *na,
699 	enum txrx tx, u_int n, u_int new_cur);
700 int netmap_ring_reinit(struct netmap_kring *);
701 
702 /* default functions to handle rx/tx interrupts */
703 int netmap_rx_irq(struct ifnet *, u_int, u_int *);
704 #define netmap_tx_irq(_n, _q) netmap_rx_irq(_n, _q, NULL)
705 void netmap_common_irq(struct ifnet *, u_int, u_int *work_done);
706 
707 void netmap_disable_all_rings(struct ifnet *);
708 void netmap_enable_all_rings(struct ifnet *);
709 void netmap_disable_ring(struct netmap_kring *kr);
710 
711 
712 /* set/clear native flags and if_transmit/netdev_ops */
713 static inline void
714 nm_set_native_flags(struct netmap_adapter *na)
715 {
716 	struct ifnet *ifp = na->ifp;
717 
718 	na->na_flags |= (NAF_NATIVE_ON | NAF_NETMAP_ON);
719 #ifdef IFCAP_NETMAP /* or FreeBSD ? */
720 	ifp->if_capenable |= IFCAP_NETMAP;
721 #endif
722 #ifdef __FreeBSD__
723 	na->if_transmit = ifp->if_transmit;
724 	ifp->if_transmit = netmap_transmit;
725 #else
726 	na->if_transmit = (void *)ifp->netdev_ops;
727 	ifp->netdev_ops = &((struct netmap_hw_adapter *)na)->nm_ndo;
728 #endif
729 }
730 
731 
732 static inline void
733 nm_clear_native_flags(struct netmap_adapter *na)
734 {
735 	struct ifnet *ifp = na->ifp;
736 
737 #ifdef __FreeBSD__
738 	ifp->if_transmit = na->if_transmit;
739 #else
740 	ifp->netdev_ops = (void *)na->if_transmit;
741 #endif
742 	na->na_flags &= ~(NAF_NATIVE_ON | NAF_NETMAP_ON);
743 #ifdef IFCAP_NETMAP /* or FreeBSD ? */
744 	ifp->if_capenable &= ~IFCAP_NETMAP;
745 #endif
746 }
747 
748 
749 /*
750  * validates parameters in the ring/kring, returns a value for head
751  * If any error, returns ring_size to force a reinit.
752  */
753 uint32_t nm_txsync_prologue(struct netmap_kring *);
754 
755 
756 /*
757  * validates parameters in the ring/kring, returns a value for head,
758  * and the 'reserved' value in the argument.
759  * If any error, returns ring_size lim to force a reinit.
760  */
761 uint32_t nm_rxsync_prologue(struct netmap_kring *);
762 
763 
764 /*
765  * update kring and ring at the end of txsync.
766  */
767 static inline void
768 nm_txsync_finalize(struct netmap_kring *kring)
769 {
770 	/* update ring head/tail to what the kernel knows */
771 	kring->ring->tail = kring->rtail = kring->nr_hwtail;
772 	kring->ring->head = kring->rhead = kring->nr_hwcur;
773 
774 	/* note, head/rhead/hwcur might be behind cur/rcur
775 	 * if no carrier
776 	 */
777 	ND(5, "%s now hwcur %d hwtail %d head %d cur %d tail %d",
778 		kring->name, kring->nr_hwcur, kring->nr_hwtail,
779 		kring->rhead, kring->rcur, kring->rtail);
780 }
781 
782 
783 /*
784  * update kring and ring at the end of rxsync
785  */
786 static inline void
787 nm_rxsync_finalize(struct netmap_kring *kring)
788 {
789 	/* tell userspace that there might be new packets */
790 	//struct netmap_ring *ring = kring->ring;
791 	ND("head %d cur %d tail %d -> %d", ring->head, ring->cur, ring->tail,
792 		kring->nr_hwtail);
793 	kring->ring->tail = kring->rtail = kring->nr_hwtail;
794 	/* make a copy of the state for next round */
795 	kring->rhead = kring->ring->head;
796 	kring->rcur = kring->ring->cur;
797 }
798 
799 
800 /* check/fix address and len in tx rings */
801 #if 1 /* debug version */
802 #define	NM_CHECK_ADDR_LEN(_a, _l)	do {				\
803 	if (_a == netmap_buffer_base || _l > NETMAP_BUF_SIZE) {		\
804 		RD(5, "bad addr/len ring %d slot %d idx %d len %d",	\
805 			ring_nr, nm_i, slot->buf_idx, len);		\
806 		if (_l > NETMAP_BUF_SIZE)				\
807 			_l = NETMAP_BUF_SIZE;				\
808 	} } while (0)
809 #else /* no debug version */
810 #define	NM_CHECK_ADDR_LEN(_a, _l)	do {				\
811 		if (_l > NETMAP_BUF_SIZE)				\
812 			_l = NETMAP_BUF_SIZE;				\
813 	} while (0)
814 #endif
815 
816 
817 /*---------------------------------------------------------------*/
818 /*
819  * Support routines to be used with the VALE switch
820  */
821 int netmap_update_config(struct netmap_adapter *na);
822 int netmap_krings_create(struct netmap_adapter *na, u_int ntx, u_int nrx, u_int tailroom);
823 void netmap_krings_delete(struct netmap_adapter *na);
824 int netmap_rxsync_from_host(struct netmap_adapter *na, struct thread *td, void *pwait);
825 
826 
827 struct netmap_if *
828 netmap_do_regif(struct netmap_priv_d *priv, struct netmap_adapter *na,
829 	uint16_t ringid, int *err);
830 
831 
832 
833 u_int nm_bound_var(u_int *v, u_int dflt, u_int lo, u_int hi, const char *msg);
834 int netmap_get_na(struct nmreq *nmr, struct netmap_adapter **na, int create);
835 int netmap_get_hw_na(struct ifnet *ifp, struct netmap_adapter **na);
836 
837 
838 #ifdef WITH_VALE
839 /*
840  * The following bridge-related functions are used by other
841  * kernel modules.
842  *
843  * VALE only supports unicast or broadcast. The lookup
844  * function can return 0 .. NM_BDG_MAXPORTS-1 for regular ports,
845  * NM_BDG_MAXPORTS for broadcast, NM_BDG_MAXPORTS+1 for unknown.
846  * XXX in practice "unknown" might be handled same as broadcast.
847  */
848 typedef u_int (*bdg_lookup_fn_t)(char *buf, u_int len,
849 		uint8_t *ring_nr, struct netmap_vp_adapter *);
850 u_int netmap_bdg_learning(char *, u_int, uint8_t *,
851 		struct netmap_vp_adapter *);
852 
853 #define	NM_BDG_MAXPORTS		254	/* up to 254 */
854 #define	NM_BDG_BROADCAST	NM_BDG_MAXPORTS
855 #define	NM_BDG_NOPORT		(NM_BDG_MAXPORTS+1)
856 
857 #define	NM_NAME			"vale"	/* prefix for bridge port name */
858 
859 
860 /* these are redefined in case of no VALE support */
861 int netmap_get_bdg_na(struct nmreq *nmr, struct netmap_adapter **na, int create);
862 void netmap_init_bridges(void);
863 int netmap_bdg_ctl(struct nmreq *nmr, bdg_lookup_fn_t func);
864 
865 #else /* !WITH_VALE */
866 #define	netmap_get_bdg_na(_1, _2, _3)	0
867 #define netmap_init_bridges(_1)
868 #define	netmap_bdg_ctl(_1, _2)	EINVAL
869 #endif /* !WITH_VALE */
870 
871 /* Various prototypes */
872 int netmap_poll(struct cdev *dev, int events, struct thread *td);
873 int netmap_init(void);
874 void netmap_fini(void);
875 int netmap_get_memory(struct netmap_priv_d* p);
876 void netmap_dtor(void *data);
877 int netmap_dtor_locked(struct netmap_priv_d *priv);
878 
879 int netmap_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag, struct thread *td);
880 
881 /* netmap_adapter creation/destruction */
882 #define NM_IFPNAME(ifp) ((ifp) ? (ifp)->if_xname : "zombie")
883 
884 // #define NM_DEBUG_PUTGET 1
885 
886 #ifdef NM_DEBUG_PUTGET
887 
888 #define NM_DBG(f) __##f
889 
890 void __netmap_adapter_get(struct netmap_adapter *na);
891 
892 #define netmap_adapter_get(na) 				\
893 	do {						\
894 		struct netmap_adapter *__na = na;	\
895 		D("getting %p:%s (%d)", __na, NM_IFPNAME(__na->ifp), __na->na_refcount);	\
896 		__netmap_adapter_get(__na);		\
897 	} while (0)
898 
899 int __netmap_adapter_put(struct netmap_adapter *na);
900 
901 #define netmap_adapter_put(na)				\
902 	do {						\
903 		struct netmap_adapter *__na = na;	\
904 		D("putting %p:%s (%d)", __na, NM_IFPNAME(__na->ifp), __na->na_refcount);	\
905 		__netmap_adapter_put(__na);		\
906 	} while (0)
907 
908 #else /* !NM_DEBUG_PUTGET */
909 
910 #define NM_DBG(f) f
911 void netmap_adapter_get(struct netmap_adapter *na);
912 int netmap_adapter_put(struct netmap_adapter *na);
913 
914 #endif /* !NM_DEBUG_PUTGET */
915 
916 
917 /*
918  * module variables
919  */
920 extern u_int netmap_buf_size;
921 #define NETMAP_BUF_SIZE	netmap_buf_size	// XXX remove
922 extern int netmap_mitigate;	// XXX not really used
923 extern int netmap_no_pendintr;
924 extern u_int netmap_total_buffers;	// global allocator
925 extern char *netmap_buffer_base;	// global allocator
926 extern int netmap_verbose;	// XXX debugging
927 enum {                                  /* verbose flags */
928 	NM_VERB_ON = 1,                 /* generic verbose */
929 	NM_VERB_HOST = 0x2,             /* verbose host stack */
930 	NM_VERB_RXSYNC = 0x10,          /* verbose on rxsync/txsync */
931 	NM_VERB_TXSYNC = 0x20,
932 	NM_VERB_RXINTR = 0x100,         /* verbose on rx/tx intr (driver) */
933 	NM_VERB_TXINTR = 0x200,
934 	NM_VERB_NIC_RXSYNC = 0x1000,    /* verbose on rx/tx intr (driver) */
935 	NM_VERB_NIC_TXSYNC = 0x2000,
936 };
937 
938 extern int netmap_txsync_retry;
939 extern int netmap_generic_mit;
940 extern int netmap_generic_ringsize;
941 
942 /*
943  * NA returns a pointer to the struct netmap adapter from the ifp,
944  * WNA is used to write it.
945  */
946 #ifndef WNA
947 #define	WNA(_ifp)	(_ifp)->if_pspare[0]
948 #endif
949 #define	NA(_ifp)	((struct netmap_adapter *)WNA(_ifp))
950 
951 /*
952  * Macros to determine if an interface is netmap capable or netmap enabled.
953  * See the magic field in struct netmap_adapter.
954  */
955 #ifdef __FreeBSD__
956 /*
957  * on FreeBSD just use if_capabilities and if_capenable.
958  */
959 #define NETMAP_CAPABLE(ifp)	(NA(ifp) &&		\
960 	(ifp)->if_capabilities & IFCAP_NETMAP )
961 
962 #define	NETMAP_SET_CAPABLE(ifp)				\
963 	(ifp)->if_capabilities |= IFCAP_NETMAP
964 
965 #else	/* linux */
966 
967 /*
968  * on linux:
969  * we check if NA(ifp) is set and its first element has a related
970  * magic value. The capenable is within the struct netmap_adapter.
971  */
972 #define	NETMAP_MAGIC	0x52697a7a
973 
974 #define NETMAP_CAPABLE(ifp)	(NA(ifp) &&		\
975 	((uint32_t)(uintptr_t)NA(ifp) ^ NA(ifp)->magic) == NETMAP_MAGIC )
976 
977 #define	NETMAP_SET_CAPABLE(ifp)				\
978 	NA(ifp)->magic = ((uint32_t)(uintptr_t)NA(ifp)) ^ NETMAP_MAGIC
979 
980 #endif	/* linux */
981 
982 #ifdef __FreeBSD__
983 
984 /* Callback invoked by the dma machinery after a successful dmamap_load */
985 static void netmap_dmamap_cb(__unused void *arg,
986     __unused bus_dma_segment_t * segs, __unused int nseg, __unused int error)
987 {
988 }
989 
990 /* bus_dmamap_load wrapper: call aforementioned function if map != NULL.
991  * XXX can we do it without a callback ?
992  */
993 static inline void
994 netmap_load_map(bus_dma_tag_t tag, bus_dmamap_t map, void *buf)
995 {
996 	if (map)
997 		bus_dmamap_load(tag, map, buf, NETMAP_BUF_SIZE,
998 		    netmap_dmamap_cb, NULL, BUS_DMA_NOWAIT);
999 }
1000 
1001 /* update the map when a buffer changes. */
1002 static inline void
1003 netmap_reload_map(bus_dma_tag_t tag, bus_dmamap_t map, void *buf)
1004 {
1005 	if (map) {
1006 		bus_dmamap_unload(tag, map);
1007 		bus_dmamap_load(tag, map, buf, NETMAP_BUF_SIZE,
1008 		    netmap_dmamap_cb, NULL, BUS_DMA_NOWAIT);
1009 	}
1010 }
1011 
1012 #else /* linux */
1013 
1014 /*
1015  * XXX How do we redefine these functions:
1016  *
1017  * on linux we need
1018  *	dma_map_single(&pdev->dev, virt_addr, len, direction)
1019  *	dma_unmap_single(&adapter->pdev->dev, phys_addr, len, direction
1020  * The len can be implicit (on netmap it is NETMAP_BUF_SIZE)
1021  * unfortunately the direction is not, so we need to change
1022  * something to have a cross API
1023  */
1024 #define netmap_load_map(_t, _m, _b)
1025 #define netmap_reload_map(_t, _m, _b)
1026 #if 0
1027 	struct e1000_buffer *buffer_info =  &tx_ring->buffer_info[l];
1028 	/* set time_stamp *before* dma to help avoid a possible race */
1029 	buffer_info->time_stamp = jiffies;
1030 	buffer_info->mapped_as_page = false;
1031 	buffer_info->length = len;
1032 	//buffer_info->next_to_watch = l;
1033 	/* reload dma map */
1034 	dma_unmap_single(&adapter->pdev->dev, buffer_info->dma,
1035 			NETMAP_BUF_SIZE, DMA_TO_DEVICE);
1036 	buffer_info->dma = dma_map_single(&adapter->pdev->dev,
1037 			addr, NETMAP_BUF_SIZE, DMA_TO_DEVICE);
1038 
1039 	if (dma_mapping_error(&adapter->pdev->dev, buffer_info->dma)) {
1040 		D("dma mapping error");
1041 		/* goto dma_error; See e1000_put_txbuf() */
1042 		/* XXX reset */
1043 	}
1044 	tx_desc->buffer_addr = htole64(buffer_info->dma); //XXX
1045 
1046 #endif
1047 
1048 /*
1049  * The bus_dmamap_sync() can be one of wmb() or rmb() depending on direction.
1050  */
1051 #define bus_dmamap_sync(_a, _b, _c)
1052 
1053 #endif /* linux */
1054 
1055 
1056 /*
1057  * functions to map NIC to KRING indexes (n2k) and vice versa (k2n)
1058  */
1059 static inline int
1060 netmap_idx_n2k(struct netmap_kring *kr, int idx)
1061 {
1062 	int n = kr->nkr_num_slots;
1063 	idx += kr->nkr_hwofs;
1064 	if (idx < 0)
1065 		return idx + n;
1066 	else if (idx < n)
1067 		return idx;
1068 	else
1069 		return idx - n;
1070 }
1071 
1072 
1073 static inline int
1074 netmap_idx_k2n(struct netmap_kring *kr, int idx)
1075 {
1076 	int n = kr->nkr_num_slots;
1077 	idx -= kr->nkr_hwofs;
1078 	if (idx < 0)
1079 		return idx + n;
1080 	else if (idx < n)
1081 		return idx;
1082 	else
1083 		return idx - n;
1084 }
1085 
1086 
1087 /* Entries of the look-up table. */
1088 struct lut_entry {
1089 	void *vaddr;		/* virtual address. */
1090 	vm_paddr_t paddr;	/* physical address. */
1091 };
1092 
1093 struct netmap_obj_pool;
1094 extern struct lut_entry *netmap_buffer_lut;
1095 #define NMB_VA(i)	(netmap_buffer_lut[i].vaddr)
1096 #define NMB_PA(i)	(netmap_buffer_lut[i].paddr)
1097 
1098 /*
1099  * NMB return the virtual address of a buffer (buffer 0 on bad index)
1100  * PNMB also fills the physical address
1101  */
1102 static inline void *
1103 NMB(struct netmap_slot *slot)
1104 {
1105 	uint32_t i = slot->buf_idx;
1106 	return (unlikely(i >= netmap_total_buffers)) ?  NMB_VA(0) : NMB_VA(i);
1107 }
1108 
1109 static inline void *
1110 PNMB(struct netmap_slot *slot, uint64_t *pp)
1111 {
1112 	uint32_t i = slot->buf_idx;
1113 	void *ret = (i >= netmap_total_buffers) ? NMB_VA(0) : NMB_VA(i);
1114 
1115 	*pp = (i >= netmap_total_buffers) ? NMB_PA(0) : NMB_PA(i);
1116 	return ret;
1117 }
1118 
1119 /* Generic version of NMB, which uses device-specific memory. */
1120 static inline void *
1121 BDG_NMB(struct netmap_adapter *na, struct netmap_slot *slot)
1122 {
1123 	struct lut_entry *lut = na->na_lut;
1124 	uint32_t i = slot->buf_idx;
1125 	return (unlikely(i >= na->na_lut_objtotal)) ?
1126 		lut[0].vaddr : lut[i].vaddr;
1127 }
1128 
1129 
1130 
1131 void netmap_txsync_to_host(struct netmap_adapter *na);
1132 
1133 
1134 /*
1135  * Structure associated to each thread which registered an interface.
1136  *
1137  * The first 4 fields of this structure are written by NIOCREGIF and
1138  * read by poll() and NIOC?XSYNC.
1139  *
1140  * There is low contention among writers (a correct user program
1141  * should have none) and among writers and readers, so we use a
1142  * single global lock to protect the structure initialization;
1143  * since initialization involves the allocation of memory,
1144  * we reuse the memory allocator lock.
1145  *
1146  * Read access to the structure is lock free. Readers must check that
1147  * np_nifp is not NULL before using the other fields.
1148  * If np_nifp is NULL initialization has not been performed,
1149  * so they should return an error to userspace.
1150  *
1151  * The ref_done field is used to regulate access to the refcount in the
1152  * memory allocator. The refcount must be incremented at most once for
1153  * each open("/dev/netmap"). The increment is performed by the first
1154  * function that calls netmap_get_memory() (currently called by
1155  * mmap(), NIOCGINFO and NIOCREGIF).
1156  * If the refcount is incremented, it is then decremented when the
1157  * private structure is destroyed.
1158  */
1159 struct netmap_priv_d {
1160 	struct netmap_if * volatile np_nifp;	/* netmap if descriptor. */
1161 
1162 	struct netmap_adapter	*np_na;
1163 	int		np_ringid;	/* from the ioctl */
1164 	u_int		np_qfirst, np_qlast;	/* range of rings to scan */
1165 	uint16_t	np_txpoll;
1166 
1167 	struct netmap_mem_d     *np_mref;	/* use with NMG_LOCK held */
1168 	/* np_refcount is only used on FreeBSD */
1169 	int		np_refcount;	/* use with NMG_LOCK held */
1170 };
1171 
1172 
1173 /*
1174  * generic netmap emulation for devices that do not have
1175  * native netmap support.
1176  */
1177 int generic_netmap_attach(struct ifnet *ifp);
1178 
1179 int netmap_catch_rx(struct netmap_adapter *na, int intercept);
1180 void generic_rx_handler(struct ifnet *ifp, struct mbuf *m);;
1181 void netmap_catch_tx(struct netmap_generic_adapter *na, int enable);
1182 int generic_xmit_frame(struct ifnet *ifp, struct mbuf *m, void *addr, u_int len, u_int ring_nr);
1183 int generic_find_num_desc(struct ifnet *ifp, u_int *tx, u_int *rx);
1184 void generic_find_num_queues(struct ifnet *ifp, u_int *txq, u_int *rxq);
1185 
1186 /*
1187  * netmap_mitigation API. This is used by the generic adapter
1188  * to reduce the number of interrupt requests/selwakeup
1189  * to clients on incoming packets.
1190  */
1191 void netmap_mitigation_init(struct netmap_generic_adapter *na);
1192 void netmap_mitigation_start(struct netmap_generic_adapter *na);
1193 void netmap_mitigation_restart(struct netmap_generic_adapter *na);
1194 int netmap_mitigation_active(struct netmap_generic_adapter *na);
1195 void netmap_mitigation_cleanup(struct netmap_generic_adapter *na);
1196 
1197 #endif /* _NET_NETMAP_KERN_H_ */
1198