xref: /freebsd/sys/dev/netmap/netmap_kern.h (revision f9790aeb8869bfcedf111517bace712b390e6cc5)
1 /*
2  * Copyright (C) 2011-2013 Matteo Landi, Luigi Rizzo. All rights reserved.
3  * Copyright (C) 2013 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)	((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 #define prefetch(x)     __builtin_prefetch(x)
65 
66 MALLOC_DECLARE(M_NETMAP);
67 
68 // XXX linux struct, not used in FreeBSD
69 struct net_device_ops {
70 };
71 struct hrtimer {
72 };
73 
74 #elif defined (linux)
75 
76 #define	NM_LOCK_T	safe_spinlock_t	// see bsd_glue.h
77 #define	NM_SELINFO_T	wait_queue_head_t
78 #define	MBUF_LEN(m)	((m)->len)
79 #define	MBUF_IFP(m)	((m)->dev)
80 #define	NM_SEND_UP(ifp, m)	netif_rx(m)
81 
82 #define NM_ATOMIC_T	volatile long unsigned int
83 
84 // XXX a mtx would suffice here too 20130404 gl
85 #define NMG_LOCK_T		struct semaphore
86 #define NMG_LOCK_INIT()		sema_init(&netmap_global_lock, 1)
87 #define NMG_LOCK_DESTROY()
88 #define NMG_LOCK()		down(&netmap_global_lock)
89 #define NMG_UNLOCK()		up(&netmap_global_lock)
90 #define NMG_LOCK_ASSERT()	//	XXX to be completed
91 
92 #ifndef DEV_NETMAP
93 #define DEV_NETMAP
94 #endif /* DEV_NETMAP */
95 
96 /*
97  * IFCAP_NETMAP goes into net_device's priv_flags (if_capenable).
98  * This was 16 bits up to linux 2.6.36, so we need a 16 bit value on older
99  * platforms and tolerate the clash with IFF_DYNAMIC and IFF_BRIDGE_PORT.
100  * For the 32-bit value, 0x100000 has no clashes until at least 3.5.1
101  */
102 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,37)
103 #define IFCAP_NETMAP	0x8000
104 #else
105 #define IFCAP_NETMAP	0x200000
106 #endif
107 
108 #elif defined (__APPLE__)
109 
110 #warning apple support is incomplete.
111 #define likely(x)	__builtin_expect(!!(x), 1)
112 #define unlikely(x)	__builtin_expect(!!(x), 0)
113 #define	NM_LOCK_T	IOLock *
114 #define	NM_SELINFO_T	struct selinfo
115 #define	MBUF_LEN(m)	((m)->m_pkthdr.len)
116 #define	NM_SEND_UP(ifp, m)	((ifp)->if_input)(ifp, m)
117 
118 #else
119 
120 #error unsupported platform
121 
122 #endif /* end - platform-specific code */
123 
124 #define ND(format, ...)
125 #define D(format, ...)						\
126 	do {							\
127 		struct timeval __xxts;				\
128 		microtime(&__xxts);				\
129 		printf("%03d.%06d %s [%d] " format "\n",	\
130 		(int)__xxts.tv_sec % 1000, (int)__xxts.tv_usec,	\
131 		__FUNCTION__, __LINE__, ##__VA_ARGS__);		\
132 	} while (0)
133 
134 /* rate limited, lps indicates how many per second */
135 #define RD(lps, format, ...)					\
136 	do {							\
137 		static int t0, __cnt;				\
138 		if (t0 != time_second) {			\
139 			t0 = time_second;			\
140 			__cnt = 0;				\
141 		}						\
142 		if (__cnt++ < lps)				\
143 			D(format, ##__VA_ARGS__);		\
144 	} while (0)
145 
146 struct netmap_adapter;
147 struct nm_bdg_fwd;
148 struct nm_bridge;
149 struct netmap_priv_d;
150 
151 const char *nm_dump_buf(char *p, int len, int lim, char *dst);
152 
153 #include "netmap_mbq.h"
154 
155 extern NMG_LOCK_T	netmap_global_lock;
156 
157 /*
158  * private, kernel view of a ring. Keeps track of the status of
159  * a ring across system calls.
160  *
161  *	nr_hwcur	index of the next buffer to refill.
162  *			It corresponds to ring->cur - ring->reserved
163  *
164  *	nr_hwavail	the number of slots "owned" by userspace.
165  *			nr_hwavail =:= ring->avail + ring->reserved
166  *
167  * The indexes in the NIC and netmap rings are offset by nkr_hwofs slots.
168  * This is so that, on a reset, buffers owned by userspace are not
169  * modified by the kernel. In particular:
170  * RX rings: the next empty buffer (hwcur + hwavail + hwofs) coincides with
171  * 	the next empty buffer as known by the hardware (next_to_check or so).
172  * TX rings: hwcur + hwofs coincides with next_to_send
173  *
174  * Clients cannot issue concurrent syscall on a ring. The system
175  * detects this and reports an error using two flags,
176  * NKR_WBUSY and NKR_RBUSY
177  * For received packets, slot->flags is set to nkr_slot_flags
178  * so we can provide a proper initial value (e.g. set NS_FORWARD
179  * when operating in 'transparent' mode).
180  *
181  * The following fields are used to implement lock-free copy of packets
182  * from input to output ports in VALE switch:
183  *	nkr_hwlease	buffer after the last one being copied.
184  *			A writer in nm_bdg_flush reserves N buffers
185  *			from nr_hwlease, advances it, then does the
186  *			copy outside the lock.
187  *			In RX rings (used for VALE ports),
188  *			nkr_hwcur + nkr_hwavail <= nkr_hwlease < nkr_hwcur+N-1
189  *			In TX rings (used for NIC or host stack ports)
190  *			nkr_hwcur <= nkr_hwlease < nkr_hwcur+ nkr_hwavail
191  *	nkr_leases	array of nkr_num_slots where writers can report
192  *			completion of their block. NR_NOSLOT (~0) indicates
193  *			that the writer has not finished yet
194  *	nkr_lease_idx	index of next free slot in nr_leases, to be assigned
195  *
196  * The kring is manipulated by txsync/rxsync and generic netmap function.
197  * q_lock is used to arbitrate access to the kring from within the netmap
198  * code, and this and other protections guarantee that there is never
199  * more than 1 concurrent call to txsync or rxsync. So we are free
200  * to manipulate the kring from within txsync/rxsync without any extra
201  * locks.
202  */
203 struct netmap_kring {
204 	struct netmap_ring *ring;
205 	uint32_t nr_hwcur;
206 	uint32_t nr_hwavail;
207 	uint32_t nr_kflags;	/* private driver flags */
208 	int32_t nr_hwreserved;
209 #define NKR_PENDINTR	0x1	// Pending interrupt.
210 	uint32_t nkr_num_slots;
211 	int32_t	nkr_hwofs;	/* offset between NIC and netmap ring */
212 
213 	uint16_t	nkr_slot_flags;	/* initial value for flags */
214 	struct netmap_adapter *na;
215 	struct nm_bdg_fwd *nkr_ft;
216 	uint32_t *nkr_leases;
217 #define NR_NOSLOT	((uint32_t)~0)
218 	uint32_t nkr_hwlease;
219 	uint32_t nkr_lease_idx;
220 
221 	NM_SELINFO_T si;	/* poll/select wait queue */
222 	NM_LOCK_T q_lock;	/* protects kring and ring. */
223 	NM_ATOMIC_T nr_busy;	/* prevent concurrent syscalls */
224 
225 	volatile int nkr_stopped;
226 
227 	/* support for adapters without native netmap support.
228 	 * On tx rings we preallocate an array of tx buffers
229 	 * (same size as the netmap ring), on rx rings we
230 	 * store incoming packets in a queue.
231 	 * XXX who writes to the rx queue ?
232 	 */
233 	struct mbuf **tx_pool;
234 	u_int nr_ntc;                   /* Emulation of a next-to-clean RX ring pointer. */
235 	struct mbq rx_queue;            /* A queue for intercepted rx mbufs. */
236 
237 } __attribute__((__aligned__(64)));
238 
239 
240 /* return the next index, with wraparound */
241 static inline uint32_t
242 nm_next(uint32_t i, uint32_t lim)
243 {
244 	return unlikely (i == lim) ? 0 : i + 1;
245 }
246 
247 /*
248  *
249  * Here is the layout for the Rx and Tx rings.
250 
251        RxRING                            TxRING
252 
253       +-----------------+            +-----------------+
254       |                 |            |                 |
255       |XXX free slot XXX|            |XXX free slot XXX|
256       +-----------------+            +-----------------+
257       |                 |<-hwcur     |                 |<-hwcur
258       | reserved    h   |            | (ready          |
259       +-----------  w  -+            |  to be          |
260  cur->|             a   |            |  sent)      h   |
261       |             v   |            +----------   w   |
262       |             a   |       cur->| (being      a   |
263       |             i   |            |  prepared)  v   |
264       | avail       l   |            |             a   |
265       +-----------------+            +  a  ------  i   +
266       |                 | ...        |  v          l   |<-hwlease
267       | (being          | ...        |  a              | ...
268       |  prepared)      | ...        |  i              | ...
269       +-----------------+ ...        |  l              | ...
270       |                 |<-hwlease   +-----------------+
271       |                 |            |                 |
272       |                 |            |                 |
273       |                 |            |                 |
274       |                 |            |                 |
275       +-----------------+            +-----------------+
276 
277  * The cur/avail (user view) and hwcur/hwavail (kernel view)
278  * are used in the normal operation of the card.
279  *
280  * When a ring is the output of a switch port (Rx ring for
281  * a VALE port, Tx ring for the host stack or NIC), slots
282  * are reserved in blocks through 'hwlease' which points
283  * to the next unused slot.
284  * On an Rx ring, hwlease is always after hwavail,
285  * and completions cause avail to advance.
286  * On a Tx ring, hwlease is always between cur and hwavail,
287  * and completions cause cur to advance.
288  *
289  * nm_kr_space() returns the maximum number of slots that
290  * can be assigned.
291  * nm_kr_lease() reserves the required number of buffers,
292  *    advances nkr_hwlease and also returns an entry in
293  *    a circular array where completions should be reported.
294  */
295 
296 
297 
298 
299 enum txrx { NR_RX = 0, NR_TX = 1 };
300 
301 /*
302  * The "struct netmap_adapter" extends the "struct adapter"
303  * (or equivalent) device descriptor.
304  * It contains all base fields needed to support netmap operation.
305  * There are in fact different types of netmap adapters
306  * (native, generic, VALE switch...) so a netmap_adapter is
307  * just the first field in the derived type.
308  */
309 struct netmap_adapter {
310 	/*
311 	 * On linux we do not have a good way to tell if an interface
312 	 * is netmap-capable. So we always use the following trick:
313 	 * NA(ifp) points here, and the first entry (which hopefully
314 	 * always exists and is at least 32 bits) contains a magic
315 	 * value which we can use to detect that the interface is good.
316 	 */
317 	uint32_t magic;
318 	uint32_t na_flags;	/* enabled, and other flags */
319 #define NAF_SKIP_INTR	1	/* use the regular interrupt handler.
320 				 * useful during initialization
321 				 */
322 #define NAF_SW_ONLY	2	/* forward packets only to sw adapter */
323 #define NAF_BDG_MAYSLEEP 4	/* the bridge is allowed to sleep when
324 				 * forwarding packets coming from this
325 				 * interface
326 				 */
327 #define NAF_MEM_OWNER	8	/* the adapter is responsible for the
328 				 * deallocation of the memory allocator
329 				 */
330 #define NAF_NATIVE_ON   16      /* the adapter is native and the attached
331 				 * interface is in netmap mode
332 				 */
333 #define	NAF_NETMAP_ON	32	/* netmap is active (either native or
334 				 * emulated. Where possible (e.g. FreeBSD)
335 				 * IFCAP_NETMAP also mirrors this flag.
336 				 */
337 	int active_fds; /* number of user-space descriptors using this
338 			 interface, which is equal to the number of
339 			 struct netmap_if objs in the mapped region. */
340 
341 	u_int num_rx_rings; /* number of adapter receive rings */
342 	u_int num_tx_rings; /* number of adapter transmit rings */
343 
344 	u_int num_tx_desc; /* number of descriptor in each queue */
345 	u_int num_rx_desc;
346 
347 	/* tx_rings and rx_rings are private but allocated
348 	 * as a contiguous chunk of memory. Each array has
349 	 * N+1 entries, for the adapter queues and for the host queue.
350 	 */
351 	struct netmap_kring *tx_rings; /* array of TX rings. */
352 	struct netmap_kring *rx_rings; /* array of RX rings. */
353 	void *tailroom;		       /* space below the rings array */
354 				       /* (used for leases) */
355 
356 
357 	NM_SELINFO_T tx_si, rx_si;	/* global wait queues */
358 
359 	/* copy of if_qflush and if_transmit pointers, to intercept
360 	 * packets from the network stack when netmap is active.
361 	 */
362 	int     (*if_transmit)(struct ifnet *, struct mbuf *);
363 
364 	/* references to the ifnet and device routines, used by
365 	 * the generic netmap functions.
366 	 */
367 	struct ifnet *ifp; /* adapter is ifp->if_softc */
368 
369 	/* private cleanup */
370 	void (*nm_dtor)(struct netmap_adapter *);
371 
372 	int (*nm_register)(struct netmap_adapter *, int onoff);
373 
374 	int (*nm_txsync)(struct netmap_adapter *, u_int ring, int flags);
375 	int (*nm_rxsync)(struct netmap_adapter *, u_int ring, int flags);
376 #define NAF_FORCE_READ    1
377 #define NAF_FORCE_RECLAIM 2
378 	/* return configuration information */
379 	int (*nm_config)(struct netmap_adapter *,
380 		u_int *txr, u_int *txd, u_int *rxr, u_int *rxd);
381 	int (*nm_krings_create)(struct netmap_adapter *);
382 	void (*nm_krings_delete)(struct netmap_adapter *);
383 	int (*nm_notify)(struct netmap_adapter *,
384 		u_int ring, enum txrx, int flags);
385 #define NAF_GLOBAL_NOTIFY 4
386 #define NAF_DISABLE_NOTIFY 8
387 
388 	/* standard refcount to control the lifetime of the adapter
389 	 * (it should be equal to the lifetime of the corresponding ifp)
390 	 */
391 	int na_refcount;
392 
393 	/* memory allocator (opaque)
394 	 * We also cache a pointer to the lut_entry for translating
395 	 * buffer addresses, and the total number of buffers.
396 	 */
397  	struct netmap_mem_d *nm_mem;
398 	struct lut_entry *na_lut;
399 	uint32_t na_lut_objtotal;	/* max buffer index */
400 
401 	/* used internally. If non-null, the interface cannot be bound
402 	 * from userspace
403 	 */
404 	void *na_private;
405 };
406 
407 /*
408  * If the NIC is owned by the kernel
409  * (i.e., bridge), neither another bridge nor user can use it;
410  * if the NIC is owned by a user, only users can share it.
411  * Evaluation must be done under NMG_LOCK().
412  */
413 #define NETMAP_OWNED_BY_KERN(na)	(na->na_private)
414 #define NETMAP_OWNED_BY_ANY(na) \
415 	(NETMAP_OWNED_BY_KERN(na) || (na->active_fds > 0))
416 
417 
418 /*
419  * derived netmap adapters for various types of ports
420  */
421 struct netmap_vp_adapter {	/* VALE software port */
422 	struct netmap_adapter up;
423 
424 	/*
425 	 * Bridge support:
426 	 *
427 	 * bdg_port is the port number used in the bridge;
428 	 * na_bdg points to the bridge this NA is attached to.
429 	 */
430 	int bdg_port;
431 	struct nm_bridge *na_bdg;
432 	int retry;
433 
434 	u_int offset;   /* Offset of ethernet header for each packet. */
435 };
436 
437 struct netmap_hw_adapter {	/* physical device */
438 	struct netmap_adapter up;
439 
440 	struct net_device_ops nm_ndo;	// XXX linux only
441 };
442 
443 struct netmap_generic_adapter {	/* non-native device */
444 	struct netmap_hw_adapter up;
445 
446 	/* Pointer to a previously used netmap adapter. */
447 	struct netmap_adapter *prev;
448 
449 	/* generic netmap adapters support:
450 	 * a net_device_ops struct overrides ndo_select_queue(),
451 	 * save_if_input saves the if_input hook (FreeBSD),
452 	 * mit_timer and mit_pending implement rx interrupt mitigation,
453 	 */
454 	struct net_device_ops generic_ndo;
455 	void (*save_if_input)(struct ifnet *, struct mbuf *);
456 
457 	struct hrtimer mit_timer;
458 	int mit_pending;
459 };
460 
461 #ifdef WITH_VALE
462 
463 /* bridge wrapper for non VALE ports. It is used to connect real devices to the bridge.
464  *
465  * The real device must already have its own netmap adapter (hwna).  The
466  * bridge wrapper and the hwna adapter share the same set of netmap rings and
467  * buffers, but they have two separate sets of krings descriptors, with tx/rx
468  * meanings swapped:
469  *
470  *                                  netmap
471  *           bwrap     krings       rings      krings      hwna
472  *         +------+   +------+     +-----+    +------+   +------+
473  *         |tx_rings->|      |\   /|     |----|      |<-tx_rings|
474  *         |      |   +------+ \ / +-----+    +------+   |      |
475  *         |      |             X                        |      |
476  *         |      |            / \                       |      |
477  *         |      |   +------+/   \+-----+    +------+   |      |
478  *         |rx_rings->|      |     |     |----|      |<-rx_rings|
479  *         |      |   +------+     +-----+    +------+   |      |
480  *         +------+                                      +------+
481  *
482  * - packets coming from the bridge go to the brwap rx rings, which are also the
483  *   hwna tx rings.  The bwrap notify callback will then complete the hwna tx
484  *   (see netmap_bwrap_notify).
485  * - packets coming from the outside go to the hwna rx rings, which are also the
486  *   bwrap tx rings.  The (overwritten) hwna notify method will then complete
487  *   the bridge tx (see netmap_bwrap_intr_notify).
488  *
489  *   The bridge wrapper may optionally connect the hwna 'host' rings to the
490  *   bridge. This is done by using a second port in the bridge and connecting it
491  *   to the 'host' netmap_vp_adapter contained in the netmap_bwrap_adapter.
492  *   The brwap host adapter cross-links the hwna host rings in the same way as shown above.
493  *
494  * - packets coming from the bridge and directed to host stack are handled by the
495  *   bwrap host notify callback (see netmap_bwrap_host_notify)
496  * - packets coming from the host stack are still handled by the overwritten
497  *   hwna notify callback (netmap_bwrap_intr_notify), but are diverted to the
498  *   host adapter depending on the ring number.
499  *
500  */
501 struct netmap_bwrap_adapter {
502 	struct netmap_vp_adapter up;
503 	struct netmap_vp_adapter host;  /* for host rings */
504 	struct netmap_adapter *hwna;	/* the underlying device */
505 
506 	/* backup of the hwna notify callback */
507 	int (*save_notify)(struct netmap_adapter *,
508 			u_int ring, enum txrx, int flags);
509 	/* When we attach a physical interface to the bridge, we
510 	 * allow the controlling process to terminate, so we need
511 	 * a place to store the netmap_priv_d data structure.
512 	 * This is only done when physical interfaces are attached to a bridge.
513 	 */
514 	struct netmap_priv_d *na_kpriv;
515 };
516 
517 
518 /*
519  * Available space in the ring. Only used in VALE code
520  */
521 static inline uint32_t
522 nm_kr_space(struct netmap_kring *k, int is_rx)
523 {
524 	int space;
525 
526 	if (is_rx) {
527 		int busy = k->nkr_hwlease - k->nr_hwcur + k->nr_hwreserved;
528 		if (busy < 0)
529 			busy += k->nkr_num_slots;
530 		space = k->nkr_num_slots - 1 - busy;
531 	} else {
532 		space = k->nr_hwcur + k->nr_hwavail - k->nkr_hwlease;
533 		if (space < 0)
534 			space += k->nkr_num_slots;
535 	}
536 #if 0
537 	// sanity check
538 	if (k->nkr_hwlease >= k->nkr_num_slots ||
539 		k->nr_hwcur >= k->nkr_num_slots ||
540 		k->nr_hwavail >= k->nkr_num_slots ||
541 		busy < 0 ||
542 		busy >= k->nkr_num_slots) {
543 		D("invalid kring, cur %d avail %d lease %d lease_idx %d lim %d",			k->nr_hwcur, k->nr_hwavail, k->nkr_hwlease,
544 			k->nkr_lease_idx, k->nkr_num_slots);
545 	}
546 #endif
547 	return space;
548 }
549 
550 
551 
552 
553 /* make a lease on the kring for N positions. return the
554  * lease index
555  */
556 static inline uint32_t
557 nm_kr_lease(struct netmap_kring *k, u_int n, int is_rx)
558 {
559 	uint32_t lim = k->nkr_num_slots - 1;
560 	uint32_t lease_idx = k->nkr_lease_idx;
561 
562 	k->nkr_leases[lease_idx] = NR_NOSLOT;
563 	k->nkr_lease_idx = nm_next(lease_idx, lim);
564 
565 	if (n > nm_kr_space(k, is_rx)) {
566 		D("invalid request for %d slots", n);
567 		panic("x");
568 	}
569 	/* XXX verify that there are n slots */
570 	k->nkr_hwlease += n;
571 	if (k->nkr_hwlease > lim)
572 		k->nkr_hwlease -= lim + 1;
573 
574 	if (k->nkr_hwlease >= k->nkr_num_slots ||
575 		k->nr_hwcur >= k->nkr_num_slots ||
576 		k->nr_hwavail >= k->nkr_num_slots ||
577 		k->nkr_lease_idx >= k->nkr_num_slots) {
578 		D("invalid kring %s, cur %d avail %d lease %d lease_idx %d lim %d",
579 			k->na->ifp->if_xname,
580 			k->nr_hwcur, k->nr_hwavail, k->nkr_hwlease,
581 			k->nkr_lease_idx, k->nkr_num_slots);
582 	}
583 	return lease_idx;
584 }
585 
586 #endif /* WITH_VALE */
587 
588 /* return update position */
589 static inline uint32_t
590 nm_kr_rxpos(struct netmap_kring *k)
591 {
592 	uint32_t pos = k->nr_hwcur + k->nr_hwavail;
593 	if (pos >= k->nkr_num_slots)
594 		pos -= k->nkr_num_slots;
595 #if 0
596 	if (pos >= k->nkr_num_slots ||
597 		k->nkr_hwlease >= k->nkr_num_slots ||
598 		k->nr_hwcur >= k->nkr_num_slots ||
599 		k->nr_hwavail >= k->nkr_num_slots ||
600 		k->nkr_lease_idx >= k->nkr_num_slots) {
601 		D("invalid kring, cur %d avail %d lease %d lease_idx %d lim %d",			k->nr_hwcur, k->nr_hwavail, k->nkr_hwlease,
602 			k->nkr_lease_idx, k->nkr_num_slots);
603 	}
604 #endif
605 	return pos;
606 }
607 
608 
609 /*
610  * protect against multiple threads using the same ring.
611  * also check that the ring has not been stopped.
612  * We only care for 0 or !=0 as a return code.
613  */
614 #define NM_KR_BUSY	1
615 #define NM_KR_STOPPED	2
616 
617 static __inline void nm_kr_put(struct netmap_kring *kr)
618 {
619 	NM_ATOMIC_CLEAR(&kr->nr_busy);
620 }
621 
622 static __inline int nm_kr_tryget(struct netmap_kring *kr)
623 {
624 	/* check a first time without taking the lock
625 	 * to avoid starvation for nm_kr_get()
626 	 */
627 	if (unlikely(kr->nkr_stopped)) {
628 		ND("ring %p stopped (%d)", kr, kr->nkr_stopped);
629 		return NM_KR_STOPPED;
630 	}
631 	if (unlikely(NM_ATOMIC_TEST_AND_SET(&kr->nr_busy)))
632 		return NM_KR_BUSY;
633 	/* check a second time with lock held */
634 	if (unlikely(kr->nkr_stopped)) {
635 		ND("ring %p stopped (%d)", kr, kr->nkr_stopped);
636 		nm_kr_put(kr);
637 		return NM_KR_STOPPED;
638 	}
639 	return 0;
640 }
641 
642 
643 /*
644  * The following are support routines used by individual drivers to
645  * support netmap operation.
646  *
647  * netmap_attach() initializes a struct netmap_adapter, allocating the
648  * 	struct netmap_ring's and the struct selinfo.
649  *
650  * netmap_detach() frees the memory allocated by netmap_attach().
651  *
652  * netmap_transmit() replaces the if_transmit routine of the interface,
653  *	and is used to intercept packets coming from the stack.
654  *
655  * netmap_load_map/netmap_reload_map are helper routines to set/reset
656  *	the dmamap for a packet buffer
657  *
658  * netmap_reset() is a helper routine to be called in the driver
659  *	when reinitializing a ring.
660  */
661 int netmap_attach(struct netmap_adapter *);
662 int netmap_attach_common(struct netmap_adapter *);
663 void netmap_detach_common(struct netmap_adapter *na);
664 void netmap_detach(struct ifnet *);
665 int netmap_transmit(struct ifnet *, struct mbuf *);
666 struct netmap_slot *netmap_reset(struct netmap_adapter *na,
667 	enum txrx tx, u_int n, u_int new_cur);
668 int netmap_ring_reinit(struct netmap_kring *);
669 
670 /* set/clear native flags. XXX maybe also if_transmit ? */
671 static inline void
672 nm_set_native_flags(struct netmap_adapter *na)
673 {
674 	struct ifnet *ifp = na->ifp;
675 
676 	na->na_flags |= (NAF_NATIVE_ON | NAF_NETMAP_ON);
677 #ifdef IFCAP_NETMAP /* or FreeBSD ? */
678 	ifp->if_capenable |= IFCAP_NETMAP;
679 #endif
680 #ifdef __FreeBSD__
681 	na->if_transmit = ifp->if_transmit;
682 	ifp->if_transmit = netmap_transmit;
683 #else
684 	na->if_transmit = (void *)ifp->netdev_ops;
685 	ifp->netdev_ops = &((struct netmap_hw_adapter *)na)->nm_ndo;
686 #endif
687 }
688 
689 static inline void
690 nm_clear_native_flags(struct netmap_adapter *na)
691 {
692 	struct ifnet *ifp = na->ifp;
693 
694 #ifdef __FreeBSD__
695 	ifp->if_transmit = na->if_transmit;
696 #else
697 	ifp->netdev_ops = (void *)na->if_transmit;
698 #endif
699 	na->na_flags &= ~(NAF_NATIVE_ON | NAF_NETMAP_ON);
700 #ifdef IFCAP_NETMAP /* or FreeBSD ? */
701 	ifp->if_capenable &= ~IFCAP_NETMAP;
702 #endif
703 }
704 
705 /*
706  * validates parameters in the ring/kring, returns a value for cur,
707  * and the 'new_slots' value in the argument.
708  * If any error, returns cur > lim to force a reinit.
709  */
710 u_int nm_txsync_prologue(struct netmap_kring *, u_int *);
711 
712 /*
713  * validates parameters in the ring/kring, returns a value for cur,
714  * and the 'reserved' value in the argument.
715  * If any error, returns cur > lim to force a reinit.
716  */
717 u_int nm_rxsync_prologue(struct netmap_kring *, u_int *);
718 
719 /*
720  * update kring and ring at the end of txsync
721  */
722 static inline void
723 nm_txsync_finalize(struct netmap_kring *kring, u_int cur)
724 {
725 	/* recompute hwreserved */
726 	kring->nr_hwreserved = cur - kring->nr_hwcur;
727 	if (kring->nr_hwreserved < 0)
728 		kring->nr_hwreserved += kring->nkr_num_slots;
729 
730 	/* update avail and reserved to what the kernel knows */
731 	kring->ring->avail = kring->nr_hwavail;
732 	kring->ring->reserved = kring->nr_hwreserved;
733 }
734 
735 /* check/fix address and len in tx rings */
736 #if 1 /* debug version */
737 #define	NM_CHECK_ADDR_LEN(_a, _l)	do {				\
738 	if (_a == netmap_buffer_base || _l > NETMAP_BUF_SIZE) {		\
739 		RD(5, "bad addr/len ring %d slot %d idx %d len %d",	\
740 			ring_nr, nm_i, slot->buf_idx, len);		\
741 		if (_l > NETMAP_BUF_SIZE)				\
742 			_l = NETMAP_BUF_SIZE;				\
743 	} } while (0)
744 #else /* no debug version */
745 #define	NM_CHECK_ADDR_LEN(_a, _l)	do {				\
746 		if (_l > NETMAP_BUF_SIZE)				\
747 			_l = NETMAP_BUF_SIZE;				\
748 	} while (0)
749 #endif
750 
751 
752 /*---------------------------------------------------------------*/
753 /*
754  * Support routines to be used with the VALE switch
755  */
756 int netmap_update_config(struct netmap_adapter *na);
757 int netmap_krings_create(struct netmap_adapter *na, u_int ntx, u_int nrx, u_int tailroom);
758 void netmap_krings_delete(struct netmap_adapter *na);
759 
760 struct netmap_if *
761 netmap_do_regif(struct netmap_priv_d *priv, struct netmap_adapter *na,
762 	uint16_t ringid, int *err);
763 
764 
765 
766 u_int nm_bound_var(u_int *v, u_int dflt, u_int lo, u_int hi, const char *msg);
767 int netmap_get_na(struct nmreq *nmr, struct netmap_adapter **na, int create);
768 int netmap_get_hw_na(struct ifnet *ifp, struct netmap_adapter **na);
769 
770 #ifdef WITH_VALE
771 /*
772  * The following bridge-related interfaces are used by other kernel modules
773  * In the version that only supports unicast or broadcast, the lookup
774  * function can return 0 .. NM_BDG_MAXPORTS-1 for regular ports,
775  * NM_BDG_MAXPORTS for broadcast, NM_BDG_MAXPORTS+1 for unknown.
776  * XXX in practice "unknown" might be handled same as broadcast.
777  */
778 typedef u_int (*bdg_lookup_fn_t)(char *buf, u_int len,
779 		uint8_t *ring_nr, struct netmap_vp_adapter *);
780 u_int netmap_bdg_learning(char *, u_int, uint8_t *,
781 		struct netmap_vp_adapter *);
782 
783 #define	NM_BDG_MAXPORTS		254	/* up to 254 */
784 #define	NM_BDG_BROADCAST	NM_BDG_MAXPORTS
785 #define	NM_BDG_NOPORT		(NM_BDG_MAXPORTS+1)
786 
787 #define	NM_NAME			"vale"	/* prefix for bridge port name */
788 
789 
790 /* these are redefined in case of no VALE support */
791 int netmap_get_bdg_na(struct nmreq *nmr, struct netmap_adapter **na, int create);
792 void netmap_init_bridges(void);
793 int netmap_bdg_ctl(struct nmreq *nmr, bdg_lookup_fn_t func);
794 
795 #else /* !WITH_VALE */
796 #define	netmap_get_bdg_na(_1, _2, _3)	0
797 #define netmap_init_bridges(_1)
798 #define	netmap_bdg_ctl(_1, _2)	EINVAL
799 #endif /* !WITH_VALE */
800 
801 /* Various prototypes */
802 int netmap_poll(struct cdev *dev, int events, struct thread *td);
803 
804 
805 int netmap_init(void);
806 void netmap_fini(void);
807 int netmap_get_memory(struct netmap_priv_d* p);
808 void netmap_dtor(void *data);
809 int netmap_dtor_locked(struct netmap_priv_d *priv);
810 
811 int netmap_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag, struct thread *td);
812 
813 /* netmap_adapter creation/destruction */
814 #define NM_IFPNAME(ifp) ((ifp) ? (ifp)->if_xname : "zombie")
815 #define NM_DEBUG_PUTGET 1
816 
817 #ifdef NM_DEBUG_PUTGET
818 
819 #define NM_DBG(f) __##f
820 
821 void __netmap_adapter_get(struct netmap_adapter *na);
822 
823 #define netmap_adapter_get(na) 				\
824 	do {						\
825 		struct netmap_adapter *__na = na;	\
826 		D("getting %p:%s (%d)", __na, NM_IFPNAME(__na->ifp), __na->na_refcount);	\
827 		__netmap_adapter_get(__na);		\
828 	} while (0)
829 
830 int __netmap_adapter_put(struct netmap_adapter *na);
831 
832 #define netmap_adapter_put(na)				\
833 	do {						\
834 		struct netmap_adapter *__na = na;	\
835 		D("putting %p:%s (%d)", __na, NM_IFPNAME(__na->ifp), __na->na_refcount);	\
836 		__netmap_adapter_put(__na);		\
837 	} while (0)
838 
839 #else /* !NM_DEBUG_PUTGET */
840 
841 #define NM_DBG(f) f
842 void netmap_adapter_get(struct netmap_adapter *na);
843 int netmap_adapter_put(struct netmap_adapter *na);
844 
845 #endif /* !NM_DEBUG_PUTGET */
846 
847 
848 extern u_int netmap_buf_size;
849 #define NETMAP_BUF_SIZE	netmap_buf_size	// XXX remove
850 extern int netmap_mitigate;
851 extern int netmap_no_pendintr;
852 extern u_int netmap_total_buffers;
853 extern char *netmap_buffer_base;
854 extern int netmap_verbose;	// XXX debugging
855 enum {                                  /* verbose flags */
856 	NM_VERB_ON = 1,                 /* generic verbose */
857 	NM_VERB_HOST = 0x2,             /* verbose host stack */
858 	NM_VERB_RXSYNC = 0x10,          /* verbose on rxsync/txsync */
859 	NM_VERB_TXSYNC = 0x20,
860 	NM_VERB_RXINTR = 0x100,         /* verbose on rx/tx intr (driver) */
861 	NM_VERB_TXINTR = 0x200,
862 	NM_VERB_NIC_RXSYNC = 0x1000,    /* verbose on rx/tx intr (driver) */
863 	NM_VERB_NIC_TXSYNC = 0x2000,
864 };
865 
866 extern int netmap_txsync_retry;
867 extern int netmap_generic_mit;
868 extern int netmap_generic_ringsize;
869 
870 /*
871  * NA returns a pointer to the struct netmap adapter from the ifp,
872  * WNA is used to write it.
873  */
874 #ifndef WNA
875 #define	WNA(_ifp)	(_ifp)->if_pspare[0]
876 #endif
877 #define	NA(_ifp)	((struct netmap_adapter *)WNA(_ifp))
878 
879 /*
880  * Macros to determine if an interface is netmap capable or netmap enabled.
881  * See the magic field in struct netmap_adapter.
882  */
883 #ifdef __FreeBSD__
884 /*
885  * on FreeBSD just use if_capabilities and if_capenable.
886  */
887 #define NETMAP_CAPABLE(ifp)	(NA(ifp) &&		\
888 	(ifp)->if_capabilities & IFCAP_NETMAP )
889 
890 #define	NETMAP_SET_CAPABLE(ifp)				\
891 	(ifp)->if_capabilities |= IFCAP_NETMAP
892 
893 #else	/* linux */
894 
895 /*
896  * on linux:
897  * we check if NA(ifp) is set and its first element has a related
898  * magic value. The capenable is within the struct netmap_adapter.
899  */
900 #define	NETMAP_MAGIC	0x52697a7a
901 
902 #define NETMAP_CAPABLE(ifp)	(NA(ifp) &&		\
903 	((uint32_t)(uintptr_t)NA(ifp) ^ NA(ifp)->magic) == NETMAP_MAGIC )
904 
905 #define	NETMAP_SET_CAPABLE(ifp)				\
906 	NA(ifp)->magic = ((uint32_t)(uintptr_t)NA(ifp)) ^ NETMAP_MAGIC
907 
908 #endif	/* linux */
909 
910 #ifdef __FreeBSD__
911 
912 /* Callback invoked by the dma machinery after a successfull dmamap_load */
913 static void netmap_dmamap_cb(__unused void *arg,
914     __unused bus_dma_segment_t * segs, __unused int nseg, __unused int error)
915 {
916 }
917 
918 /* bus_dmamap_load wrapper: call aforementioned function if map != NULL.
919  * XXX can we do it without a callback ?
920  */
921 static inline void
922 netmap_load_map(bus_dma_tag_t tag, bus_dmamap_t map, void *buf)
923 {
924 	if (map)
925 		bus_dmamap_load(tag, map, buf, NETMAP_BUF_SIZE,
926 		    netmap_dmamap_cb, NULL, BUS_DMA_NOWAIT);
927 }
928 
929 /* update the map when a buffer changes. */
930 static inline void
931 netmap_reload_map(bus_dma_tag_t tag, bus_dmamap_t map, void *buf)
932 {
933 	if (map) {
934 		bus_dmamap_unload(tag, map);
935 		bus_dmamap_load(tag, map, buf, NETMAP_BUF_SIZE,
936 		    netmap_dmamap_cb, NULL, BUS_DMA_NOWAIT);
937 	}
938 }
939 
940 #else /* linux */
941 
942 /*
943  * XXX How do we redefine these functions:
944  *
945  * on linux we need
946  *	dma_map_single(&pdev->dev, virt_addr, len, direction)
947  *	dma_unmap_single(&adapter->pdev->dev, phys_addr, len, direction
948  * The len can be implicit (on netmap it is NETMAP_BUF_SIZE)
949  * unfortunately the direction is not, so we need to change
950  * something to have a cross API
951  */
952 #define netmap_load_map(_t, _m, _b)
953 #define netmap_reload_map(_t, _m, _b)
954 #if 0
955 	struct e1000_buffer *buffer_info =  &tx_ring->buffer_info[l];
956 	/* set time_stamp *before* dma to help avoid a possible race */
957 	buffer_info->time_stamp = jiffies;
958 	buffer_info->mapped_as_page = false;
959 	buffer_info->length = len;
960 	//buffer_info->next_to_watch = l;
961 	/* reload dma map */
962 	dma_unmap_single(&adapter->pdev->dev, buffer_info->dma,
963 			NETMAP_BUF_SIZE, DMA_TO_DEVICE);
964 	buffer_info->dma = dma_map_single(&adapter->pdev->dev,
965 			addr, NETMAP_BUF_SIZE, DMA_TO_DEVICE);
966 
967 	if (dma_mapping_error(&adapter->pdev->dev, buffer_info->dma)) {
968 		D("dma mapping error");
969 		/* goto dma_error; See e1000_put_txbuf() */
970 		/* XXX reset */
971 	}
972 	tx_desc->buffer_addr = htole64(buffer_info->dma); //XXX
973 
974 #endif
975 
976 /*
977  * The bus_dmamap_sync() can be one of wmb() or rmb() depending on direction.
978  */
979 #define bus_dmamap_sync(_a, _b, _c)
980 
981 #endif /* linux */
982 
983 
984 /*
985  * functions to map NIC to KRING indexes (n2k) and vice versa (k2n)
986  */
987 static inline int
988 netmap_idx_n2k(struct netmap_kring *kr, int idx)
989 {
990 	int n = kr->nkr_num_slots;
991 	idx += kr->nkr_hwofs;
992 	if (idx < 0)
993 		return idx + n;
994 	else if (idx < n)
995 		return idx;
996 	else
997 		return idx - n;
998 }
999 
1000 
1001 static inline int
1002 netmap_idx_k2n(struct netmap_kring *kr, int idx)
1003 {
1004 	int n = kr->nkr_num_slots;
1005 	idx -= kr->nkr_hwofs;
1006 	if (idx < 0)
1007 		return idx + n;
1008 	else if (idx < n)
1009 		return idx;
1010 	else
1011 		return idx - n;
1012 }
1013 
1014 
1015 /* Entries of the look-up table. */
1016 struct lut_entry {
1017 	void *vaddr;		/* virtual address. */
1018 	vm_paddr_t paddr;	/* physical address. */
1019 };
1020 
1021 struct netmap_obj_pool;
1022 extern struct lut_entry *netmap_buffer_lut;
1023 #define NMB_VA(i)	(netmap_buffer_lut[i].vaddr)
1024 #define NMB_PA(i)	(netmap_buffer_lut[i].paddr)
1025 
1026 /*
1027  * NMB return the virtual address of a buffer (buffer 0 on bad index)
1028  * PNMB also fills the physical address
1029  */
1030 static inline void *
1031 NMB(struct netmap_slot *slot)
1032 {
1033 	uint32_t i = slot->buf_idx;
1034 	return (unlikely(i >= netmap_total_buffers)) ?  NMB_VA(0) : NMB_VA(i);
1035 }
1036 
1037 static inline void *
1038 PNMB(struct netmap_slot *slot, uint64_t *pp)
1039 {
1040 	uint32_t i = slot->buf_idx;
1041 	void *ret = (i >= netmap_total_buffers) ? NMB_VA(0) : NMB_VA(i);
1042 
1043 	*pp = (i >= netmap_total_buffers) ? NMB_PA(0) : NMB_PA(i);
1044 	return ret;
1045 }
1046 
1047 /* Generic version of NMB, which uses device-specific memory. */
1048 static inline void *
1049 BDG_NMB(struct netmap_adapter *na, struct netmap_slot *slot)
1050 {
1051 	struct lut_entry *lut = na->na_lut;
1052 	uint32_t i = slot->buf_idx;
1053 	return (unlikely(i >= na->na_lut_objtotal)) ?
1054 		lut[0].vaddr : lut[i].vaddr;
1055 }
1056 
1057 /* default functions to handle rx/tx interrupts */
1058 int netmap_rx_irq(struct ifnet *, u_int, u_int *);
1059 #define netmap_tx_irq(_n, _q) netmap_rx_irq(_n, _q, NULL)
1060 void netmap_common_irq(struct ifnet *, u_int, u_int *work_done);
1061 
1062 
1063 void netmap_txsync_to_host(struct netmap_adapter *na);
1064 void netmap_disable_all_rings(struct ifnet *);
1065 void netmap_enable_all_rings(struct ifnet *);
1066 void netmap_disable_ring(struct netmap_kring *kr);
1067 
1068 
1069 /* Structure associated to each thread which registered an interface.
1070  *
1071  * The first 4 fields of this structure are written by NIOCREGIF and
1072  * read by poll() and NIOC?XSYNC.
1073  * There is low contention among writers (actually, a correct user program
1074  * should have no contention among writers) and among writers and readers,
1075  * so we use a single global lock to protect the structure initialization.
1076  * Since initialization involves the allocation of memory, we reuse the memory
1077  * allocator lock.
1078  * Read access to the structure is lock free. Readers must check that
1079  * np_nifp is not NULL before using the other fields.
1080  * If np_nifp is NULL initialization has not been performed, so they should
1081  * return an error to userlevel.
1082  *
1083  * The ref_done field is used to regulate access to the refcount in the
1084  * memory allocator. The refcount must be incremented at most once for
1085  * each open("/dev/netmap"). The increment is performed by the first
1086  * function that calls netmap_get_memory() (currently called by
1087  * mmap(), NIOCGINFO and NIOCREGIF).
1088  * If the refcount is incremented, it is then decremented when the
1089  * private structure is destroyed.
1090  */
1091 struct netmap_priv_d {
1092 	struct netmap_if * volatile np_nifp;	/* netmap if descriptor. */
1093 
1094 	struct netmap_adapter	*np_na;
1095 	int		        np_ringid;	/* from the ioctl */
1096 	u_int		        np_qfirst, np_qlast;	/* range of rings to scan */
1097 	uint16_t	        np_txpoll;
1098 
1099 	struct netmap_mem_d     *np_mref;	/* use with NMG_LOCK held */
1100 	/* np_refcount is only used on FreeBSD */
1101 	int		        np_refcount;	/* use with NMG_LOCK held */
1102 };
1103 
1104 
1105 /*
1106  * generic netmap emulation for devices that do not have
1107  * native netmap support.
1108  * XXX generic_netmap_register() is only exported to implement
1109  *	nma_is_generic().
1110  */
1111 int generic_netmap_register(struct netmap_adapter *na, int enable);
1112 int generic_netmap_attach(struct ifnet *ifp);
1113 
1114 int netmap_catch_rx(struct netmap_adapter *na, int intercept);
1115 void generic_rx_handler(struct ifnet *ifp, struct mbuf *m);;
1116 void netmap_catch_packet_steering(struct netmap_generic_adapter *na, int enable);
1117 int generic_xmit_frame(struct ifnet *ifp, struct mbuf *m, void *addr, u_int len, u_int ring_nr);
1118 int generic_find_num_desc(struct ifnet *ifp, u_int *tx, u_int *rx);
1119 void generic_find_num_queues(struct ifnet *ifp, u_int *txq, u_int *rxq);
1120 
1121 static __inline int
1122 nma_is_generic(struct netmap_adapter *na)
1123 {
1124 	return na->nm_register == generic_netmap_register;
1125 }
1126 
1127 /*
1128  * netmap_mitigation API. This is used by the generic adapter
1129  * to reduce the number of interrupt requests/selwakeup
1130  * to clients on incoming packets.
1131  */
1132 void netmap_mitigation_init(struct netmap_generic_adapter *na);
1133 void netmap_mitigation_start(struct netmap_generic_adapter *na);
1134 void netmap_mitigation_restart(struct netmap_generic_adapter *na);
1135 int netmap_mitigation_active(struct netmap_generic_adapter *na);
1136 void netmap_mitigation_cleanup(struct netmap_generic_adapter *na);
1137 
1138 // int generic_timer_handler(struct hrtimer *t);
1139 
1140 #endif /* _NET_NETMAP_KERN_H_ */
1141