1 /*
2 * Copyright (C) 2011-2014 Matteo Landi, Luigi Rizzo. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
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 ``S 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: head/sys/net/netmap.h 251139 2013-05-30 14:07:14Z luigi $
29 *
30 * Definitions of constants and the structures used by the netmap
31 * framework, for the part visible to both kernel and userspace.
32 * Detailed info on netmap is available with "man netmap" or at
33 *
34 * http://info.iet.unipi.it/~luigi/netmap/
35 *
36 * This API is also used to communicate with the VALE software switch
37 */
38
39 #ifndef _NET_NETMAP_H_
40 #define _NET_NETMAP_H_
41
42 #define NETMAP_API 11 /* current API version */
43
44 #define NETMAP_MIN_API 11 /* min and max versions accepted */
45 #define NETMAP_MAX_API 15
46 /*
47 * Some fields should be cache-aligned to reduce contention.
48 * The alignment is architecture and OS dependent, but rather than
49 * digging into OS headers to find the exact value we use an estimate
50 * that should cover most architectures.
51 */
52 #define NM_CACHE_ALIGN 128
53
54 /*
55 * --- Netmap data structures ---
56 *
57 * The userspace data structures used by netmap are shown below.
58 * They are allocated by the kernel and mmap()ed by userspace threads.
59 * Pointers are implemented as memory offsets or indexes,
60 * so that they can be easily dereferenced in kernel and userspace.
61
62 KERNEL (opaque, obviously)
63
64 ====================================================================
65 |
66 USERSPACE | struct netmap_ring
67 +---->+---------------+
68 / | head,cur,tail |
69 struct netmap_if (nifp, 1 per fd) / | buf_ofs |
70 +---------------+ / | other fields |
71 | ni_tx_rings | / +===============+
72 | ni_rx_rings | / | buf_idx, len | slot[0]
73 | | / | flags, ptr |
74 | | / +---------------+
75 +===============+ / | buf_idx, len | slot[1]
76 | txring_ofs[0] | (rel.to nifp)--' | flags, ptr |
77 | txring_ofs[1] | +---------------+
78 (tx+1 entries) (num_slots entries)
79 | txring_ofs[t] | | buf_idx, len | slot[n-1]
80 +---------------+ | flags, ptr |
81 | rxring_ofs[0] | +---------------+
82 | rxring_ofs[1] |
83 (rx+1 entries)
84 | rxring_ofs[r] |
85 +---------------+
86
87 * For each "interface" (NIC, host stack, PIPE, VALE switch port) bound to
88 * a file descriptor, the mmap()ed region contains a (logically readonly)
89 * struct netmap_if pointing to struct netmap_ring's.
90 *
91 * There is one netmap_ring per physical NIC ring, plus one tx/rx ring
92 * pair attached to the host stack (this pair is unused for non-NIC ports).
93 *
94 * All physical/host stack ports share the same memory region,
95 * so that zero-copy can be implemented between them.
96 * VALE switch ports instead have separate memory regions.
97 *
98 * The netmap_ring is the userspace-visible replica of the NIC ring.
99 * Each slot has the index of a buffer (MTU-sized and residing in the
100 * mmapped region), its length and some flags. An extra 64-bit pointer
101 * is provided for user-supplied buffers in the tx path.
102 *
103 * In user space, the buffer address is computed as
104 * (char *)ring + buf_ofs + index * NETMAP_BUF_SIZE
105 *
106 * Added in NETMAP_API 11:
107 *
108 * + NIOCREGIF can request the allocation of extra spare buffers from
109 * the same memory pool. The desired number of buffers must be in
110 * nr_arg3. The ioctl may return fewer buffers, depending on memory
111 * availability. nr_arg3 will return the actual value, and, once
112 * mapped, nifp->ni_bufs_head will be the index of the first buffer.
113 *
114 * The buffers are linked to each other using the first uint32_t
115 * as the index. On close, ni_bufs_head must point to the list of
116 * buffers to be released.
117 *
118 * + NIOCREGIF can request space for extra rings (and buffers)
119 * allocated in the same memory space. The number of extra rings
120 * is in nr_arg1, and is advisory. This is a no-op on NICs where
121 * the size of the memory space is fixed.
122 *
123 * + NIOCREGIF can attach to PIPE rings sharing the same memory
124 * space with a parent device. The ifname indicates the parent device,
125 * which must already exist. Flags in nr_flags indicate if we want to
126 * bind the master or slave side, the index (from nr_ringid)
127 * is just a cookie and does not need to be sequential.
128 *
129 * + NIOCREGIF can also attach to 'monitor' rings that replicate
130 * the content of specific rings, also from the same memory space.
131 *
132 * Extra flags in nr_flags support the above functions.
133 * Application libraries may use the following naming scheme:
134 * netmap:foo all NIC ring pairs
135 * netmap:foo^ only host ring pair
136 * netmap:foo+ all NIC ring + host ring pairs
137 * netmap:foo-k the k-th NIC ring pair
138 * netmap:foo{k PIPE ring pair k, master side
139 * netmap:foo}k PIPE ring pair k, slave side
140 */
141
142 /*
143 * struct netmap_slot is a buffer descriptor
144 */
145 struct netmap_slot {
146 uint32_t buf_idx; /* buffer index */
147 uint16_t len; /* length for this slot */
148 uint16_t flags; /* buf changed, etc. */
149 uint64_t ptr; /* pointer for indirect buffers */
150 };
151
152 /*
153 * The following flags control how the slot is used
154 */
155
156 #define NS_BUF_CHANGED 0x0001 /* buf_idx changed */
157 /*
158 * must be set whenever buf_idx is changed (as it might be
159 * necessary to recompute the physical address and mapping)
160 *
161 * It is also set by the kernel whenever the buf_idx is
162 * changed internally (e.g., by pipes). Applications may
163 * use this information to know when they can reuse the
164 * contents of previously prepared buffers.
165 */
166
167 #define NS_REPORT 0x0002 /* ask the hardware to report results */
168 /*
169 * Request notification when slot is used by the hardware.
170 * Normally transmit completions are handled lazily and
171 * may be unreported. This flag lets us know when a slot
172 * has been sent (e.g. to terminate the sender).
173 */
174
175 #define NS_FORWARD 0x0004 /* pass packet 'forward' */
176 /*
177 * (Only for physical ports, rx rings with NR_FORWARD set).
178 * Slot released to the kernel (i.e. before ring->head) with
179 * this flag set are passed to the peer ring (host/NIC),
180 * thus restoring the host-NIC connection for these slots.
181 * This supports efficient traffic monitoring or firewalling.
182 */
183
184 #define NS_NO_LEARN 0x0008 /* disable bridge learning */
185 /*
186 * On a VALE switch, do not 'learn' the source port for
187 * this buffer.
188 */
189
190 #define NS_INDIRECT 0x0010 /* userspace buffer */
191 /*
192 * (VALE tx rings only) data is in a userspace buffer,
193 * whose address is in the 'ptr' field in the slot.
194 */
195
196 #define NS_MOREFRAG 0x0020 /* packet has more fragments */
197 /*
198 * (VALE ports only)
199 * Set on all but the last slot of a multi-segment packet.
200 * The 'len' field refers to the individual fragment.
201 */
202
203 #define NS_PORT_SHIFT 8
204 #define NS_PORT_MASK (0xff << NS_PORT_SHIFT)
205 /*
206 * The high 8 bits of the flag, if not zero, indicate the
207 * destination port for the VALE switch, overriding
208 * the lookup table.
209 */
210
211 #define NS_RFRAGS(_slot) ( ((_slot)->flags >> 8) & 0xff)
212 /*
213 * (VALE rx rings only) the high 8 bits
214 * are the number of fragments.
215 */
216
217
218 /*
219 * struct netmap_ring
220 *
221 * Netmap representation of a TX or RX ring (also known as "queue").
222 * This is a queue implemented as a fixed-size circular array.
223 * At the software level the important fields are: head, cur, tail.
224 *
225 * In TX rings:
226 *
227 * head first slot available for transmission.
228 * cur wakeup point. select() and poll() will unblock
229 * when 'tail' moves past 'cur'
230 * tail (readonly) first slot reserved to the kernel
231 *
232 * [head .. tail-1] can be used for new packets to send;
233 * 'head' and 'cur' must be incremented as slots are filled
234 * with new packets to be sent;
235 * 'cur' can be moved further ahead if we need more space
236 * for new transmissions. XXX todo (2014-03-12)
237 *
238 * In RX rings:
239 *
240 * head first valid received packet
241 * cur wakeup point. select() and poll() will unblock
242 * when 'tail' moves past 'cur'
243 * tail (readonly) first slot reserved to the kernel
244 *
245 * [head .. tail-1] contain received packets;
246 * 'head' and 'cur' must be incremented as slots are consumed
247 * and can be returned to the kernel;
248 * 'cur' can be moved further ahead if we want to wait for
249 * new packets without returning the previous ones.
250 *
251 * DATA OWNERSHIP/LOCKING:
252 * The netmap_ring, and all slots and buffers in the range
253 * [head .. tail-1] are owned by the user program;
254 * the kernel only accesses them during a netmap system call
255 * and in the user thread context.
256 *
257 * Other slots and buffers are reserved for use by the kernel
258 */
259 struct netmap_ring {
260 /*
261 * buf_ofs is meant to be used through macros.
262 * It contains the offset of the buffer region from this
263 * descriptor.
264 */
265 const int64_t buf_ofs;
266 const uint32_t num_slots; /* number of slots in the ring. */
267 const uint32_t nr_buf_size;
268 const uint16_t ringid;
269 const uint16_t dir; /* 0: tx, 1: rx */
270
271 uint32_t head; /* (u) first user slot */
272 uint32_t cur; /* (u) wakeup point */
273 uint32_t tail; /* (k) first kernel slot */
274
275 uint32_t flags;
276
277 struct timeval ts; /* (k) time of last *sync() */
278
279 /* opaque room for a mutex or similar object */
280 uint8_t sem[128] __attribute__((__aligned__(NM_CACHE_ALIGN)));
281
282 /* the slots follow. This struct has variable size */
283 struct netmap_slot slot[0]; /* array of slots. */
284 };
285
286
287 /*
288 * RING FLAGS
289 */
290 #define NR_TIMESTAMP 0x0002 /* set timestamp on *sync() */
291 /*
292 * updates the 'ts' field on each netmap syscall. This saves
293 * saves a separate gettimeofday(), and is not much worse than
294 * software timestamps generated in the interrupt handler.
295 */
296
297 #define NR_FORWARD 0x0004 /* enable NS_FORWARD for ring */
298 /*
299 * Enables the NS_FORWARD slot flag for the ring.
300 */
301
302
303 /*
304 * Netmap representation of an interface and its queue(s).
305 * This is initialized by the kernel when binding a file
306 * descriptor to a port, and should be considered as readonly
307 * by user programs. The kernel never uses it.
308 *
309 * There is one netmap_if for each file descriptor on which we want
310 * to select/poll.
311 * select/poll operates on one or all pairs depending on the value of
312 * nmr_queueid passed on the ioctl.
313 */
314 struct netmap_if {
315 char ni_name[IFNAMSIZ]; /* name of the interface. */
316 const uint32_t ni_version; /* API version, currently unused */
317 const uint32_t ni_flags; /* properties */
318 #define NI_PRIV_MEM 0x1 /* private memory region */
319
320 /*
321 * The number of packet rings available in netmap mode.
322 * Physical NICs can have different numbers of tx and rx rings.
323 * Physical NICs also have a 'host' ring pair.
324 * Additionally, clients can request additional ring pairs to
325 * be used for internal communication.
326 */
327 const uint32_t ni_tx_rings; /* number of HW tx rings */
328 const uint32_t ni_rx_rings; /* number of HW rx rings */
329
330 uint32_t ni_bufs_head; /* head index for extra bufs */
331 uint32_t ni_spare1[5];
332 /*
333 * The following array contains the offset of each netmap ring
334 * from this structure, in the following order:
335 * NIC tx rings (ni_tx_rings); host tx ring (1); extra tx rings;
336 * NIC rx rings (ni_rx_rings); host tx ring (1); extra rx rings.
337 *
338 * The area is filled up by the kernel on NIOCREGIF,
339 * and then only read by userspace code.
340 */
341 const ssize_t ring_ofs[0];
342 };
343
344
345 #ifndef NIOCREGIF
346 /*
347 * ioctl names and related fields
348 *
349 * NIOCTXSYNC, NIOCRXSYNC synchronize tx or rx queues,
350 * whose identity is set in NIOCREGIF through nr_ringid.
351 * These are non blocking and take no argument.
352 *
353 * NIOCGINFO takes a struct ifreq, the interface name is the input,
354 * the outputs are number of queues and number of descriptor
355 * for each queue (useful to set number of threads etc.).
356 * The info returned is only advisory and may change before
357 * the interface is bound to a file descriptor.
358 *
359 * NIOCREGIF takes an interface name within a struct nmre,
360 * and activates netmap mode on the interface (if possible).
361 *
362 * The argument to NIOCGINFO/NIOCREGIF overlays struct ifreq so we
363 * can pass it down to other NIC-related ioctls.
364 *
365 * The actual argument (struct nmreq) has a number of options to request
366 * different functions.
367 * The following are used in NIOCREGIF when nr_cmd == 0:
368 *
369 * nr_name (in)
370 * The name of the port (em0, valeXXX:YYY, etc.)
371 * limited to IFNAMSIZ for backward compatibility.
372 *
373 * nr_version (in/out)
374 * Must match NETMAP_API as used in the kernel, error otherwise.
375 * Always returns the desired value on output.
376 *
377 * nr_tx_slots, nr_tx_slots, nr_tx_rings, nr_rx_rings (in/out)
378 * On input, non-zero values may be used to reconfigure the port
379 * according to the requested values, but this is not guaranteed.
380 * On output the actual values in use are reported.
381 *
382 * nr_ringid (in)
383 * Indicates how rings should be bound to the file descriptors.
384 * If nr_flags != 0, then the low bits (in NETMAP_RING_MASK)
385 * are used to indicate the ring number, and nr_flags specifies
386 * the actual rings to bind. NETMAP_NO_TX_POLL is unaffected.
387 *
388 * NOTE: THE FOLLOWING (nr_flags == 0) IS DEPRECATED:
389 * If nr_flags == 0, NETMAP_HW_RING and NETMAP_SW_RING control
390 * the binding as follows:
391 * 0 (default) binds all physical rings
392 * NETMAP_HW_RING | ring number binds a single ring pair
393 * NETMAP_SW_RING binds only the host tx/rx rings
394 *
395 * NETMAP_NO_TX_POLL can be OR-ed to make select()/poll() push
396 * packets on tx rings only if POLLOUT is set.
397 * The default is to push any pending packet.
398 *
399 * NETMAP_DO_RX_POLL can be OR-ed to make select()/poll() release
400 * packets on rx rings also when POLLIN is NOT set.
401 * The default is to touch the rx ring only with POLLIN.
402 * Note that this is the opposite of TX because it
403 * reflects the common usage.
404 *
405 * NOTE: NETMAP_PRIV_MEM IS DEPRECATED, use nr_arg2 instead.
406 * NETMAP_PRIV_MEM is set on return for ports that do not use
407 * the global memory allocator.
408 * This information is not significant and applications
409 * should look at the region id in nr_arg2
410 *
411 * nr_flags is the recommended mode to indicate which rings should
412 * be bound to a file descriptor. Values are NR_REG_*
413 *
414 * nr_arg1 (in) The number of extra rings to be reserved.
415 * Especially when allocating a VALE port the system only
416 * allocates the amount of memory needed for the port.
417 * If more shared memory rings are desired (e.g. for pipes),
418 * the first invocation for the same basename/allocator
419 * should specify a suitable number. Memory cannot be
420 * extended after the first allocation without closing
421 * all ports on the same region.
422 *
423 * nr_arg2 (in/out) The identity of the memory region used.
424 * On input, 0 means the system decides autonomously,
425 * other values may try to select a specific region.
426 * On return the actual value is reported.
427 * Region '1' is the global allocator, normally shared
428 * by all interfaces. Other values are private regions.
429 * If two ports the same region zero-copy is possible.
430 *
431 * nr_arg3 (in/out) number of extra buffers to be allocated.
432 *
433 *
434 *
435 * nr_cmd (in) if non-zero indicates a special command:
436 * NETMAP_BDG_ATTACH and nr_name = vale*:ifname
437 * attaches the NIC to the switch; nr_ringid specifies
438 * which rings to use. Used by vale-ctl -a ...
439 * nr_arg1 = NETMAP_BDG_HOST also attaches the host port
440 * as in vale-ctl -h ...
441 *
442 * NETMAP_BDG_DETACH and nr_name = vale*:ifname
443 * disconnects a previously attached NIC.
444 * Used by vale-ctl -d ...
445 *
446 * NETMAP_BDG_LIST
447 * list the configuration of VALE switches.
448 *
449 * NETMAP_BDG_VNET_HDR
450 * Set the virtio-net header length used by the client
451 * of a VALE switch port.
452 *
453 * NETMAP_BDG_NEWIF
454 * create a persistent VALE port with name nr_name.
455 * Used by vale-ctl -n ...
456 *
457 * NETMAP_BDG_DELIF
458 * delete a persistent VALE port. Used by vale-ctl -d ...
459 *
460 * nr_arg1, nr_arg2, nr_arg3 (in/out) command specific
461 *
462 *
463 *
464 */
465
466
467 /*
468 * struct nmreq overlays a struct ifreq (just the name)
469 */
470 struct nmreq {
471 char nr_name[IFNAMSIZ];
472 uint32_t nr_version; /* API version */
473 uint32_t nr_offset; /* nifp offset in the shared region */
474 uint32_t nr_memsize; /* size of the shared region */
475 uint32_t nr_tx_slots; /* slots in tx rings */
476 uint32_t nr_rx_slots; /* slots in rx rings */
477 uint16_t nr_tx_rings; /* number of tx rings */
478 uint16_t nr_rx_rings; /* number of rx rings */
479
480 uint16_t nr_ringid; /* ring(s) we care about */
481 #define NETMAP_HW_RING 0x4000 /* single NIC ring pair */
482 #define NETMAP_SW_RING 0x2000 /* only host ring pair */
483
484 #define NETMAP_RING_MASK 0x0fff /* the ring number */
485
486 #define NETMAP_NO_TX_POLL 0x1000 /* no automatic txsync on poll */
487
488 #define NETMAP_DO_RX_POLL 0x8000 /* DO automatic rxsync on poll */
489
490 uint16_t nr_cmd;
491 #define NETMAP_BDG_ATTACH 1 /* attach the NIC */
492 #define NETMAP_BDG_DETACH 2 /* detach the NIC */
493 #define NETMAP_BDG_REGOPS 3 /* register bridge callbacks */
494 #define NETMAP_BDG_LIST 4 /* get bridge's info */
495 #define NETMAP_BDG_VNET_HDR 5 /* set the port virtio-net-hdr length */
496 #define NETMAP_BDG_OFFSET NETMAP_BDG_VNET_HDR /* deprecated alias */
497 #define NETMAP_BDG_NEWIF 6 /* create a virtual port */
498 #define NETMAP_BDG_DELIF 7 /* destroy a virtual port */
499 uint16_t nr_arg1; /* reserve extra rings in NIOCREGIF */
500 #define NETMAP_BDG_HOST 1 /* attach the host stack on ATTACH */
501
502 uint16_t nr_arg2;
503 uint32_t nr_arg3; /* req. extra buffers in NIOCREGIF */
504 uint32_t nr_flags;
505 /* various modes, extends nr_ringid */
506 uint32_t spare2[1];
507 };
508
509 #define NR_REG_MASK 0xf /* values for nr_flags */
510 enum { NR_REG_DEFAULT = 0, /* backward compat, should not be used. */
511 NR_REG_ALL_NIC = 1,
512 NR_REG_SW = 2,
513 NR_REG_NIC_SW = 3,
514 NR_REG_ONE_NIC = 4,
515 NR_REG_PIPE_MASTER = 5,
516 NR_REG_PIPE_SLAVE = 6,
517 };
518 /* monitor uses the NR_REG to select the rings to monitor */
519 #define NR_MONITOR_TX 0x100
520 #define NR_MONITOR_RX 0x200
521 #define NR_ZCOPY_MON 0x400
522 /* request exclusive access to the selected rings */
523 #define NR_EXCLUSIVE 0x800
524
525
526 /*
527 * FreeBSD uses the size value embedded in the _IOWR to determine
528 * how much to copy in/out. So we need it to match the actual
529 * data structure we pass. We put some spares in the structure
530 * to ease compatibility with other versions
531 */
532 #define NIOCGINFO _IOWR('i', 145, struct nmreq) /* return IF info */
533 #define NIOCREGIF _IOWR('i', 146, struct nmreq) /* interface register */
534 #define NIOCTXSYNC _IO('i', 148) /* sync tx queues */
535 #define NIOCRXSYNC _IO('i', 149) /* sync rx queues */
536 #define NIOCCONFIG _IOWR('i',150, struct nm_ifreq) /* for ext. modules */
537 #endif /* !NIOCREGIF */
538
539
540 /*
541 * Helper functions for kernel and userspace
542 */
543
544 /*
545 * check if space is available in the ring.
546 */
547 static inline int
nm_ring_empty(struct netmap_ring * ring)548 nm_ring_empty(struct netmap_ring *ring)
549 {
550 return (ring->cur == ring->tail);
551 }
552
553 /*
554 * Opaque structure that is passed to an external kernel
555 * module via ioctl(fd, NIOCCONFIG, req) for a user-owned
556 * bridge port (at this point ephemeral VALE interface).
557 */
558 #define NM_IFRDATA_LEN 256
559 struct nm_ifreq {
560 char nifr_name[IFNAMSIZ];
561 char data[NM_IFRDATA_LEN];
562 };
563
564 #endif /* _NET_NETMAP_H_ */
565