xref: /freebsd/lib/libnetmap/libnetmap.h (revision 8eb2bee6c0f4957c6c1cea826e59cda4d18a2a64)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (C) 2018 Universita` di Pisa
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  *   1. Redistributions of source code must retain the above copyright
12  *      notice, this list of conditions and the following disclaimer.
13  *   2. Redistributions in binary form must reproduce the above copyright
14  *      notice, this list of conditions and the following disclaimer in the
15  *      documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  * $FreeBSD$
29  */
30 
31 #ifndef LIBNETMAP_H_
32 #define LIBNETMAP_H_
33 /* if thread-safety is not needed, define LIBNETMAP_NOTHREADSAFE before including
34  * this file.
35  */
36 
37 /* NOTE: we include net/netmap_user.h without defining NETMAP_WITH_LIBS, which
38  * is deprecated. If you still need it, please define NETMAP_WITH_LIBS and
39  * include net/netmap_user.h before including this file.
40  */
41 #include <net/netmap_user.h>
42 
43 struct nmctx;
44 struct nmport_d;
45 struct nmem_d;
46 
47 /*
48  * A port open specification (portspec for brevity) has the following syntax
49  * (square brackets delimit optional parts):
50  *
51  *     subsystem:vpname[mode][options]
52  *
53  *  The "subsystem" is denoted by a prefix, possibly followed by an identifier.
54  *  There can be several kinds of subsystems, each one selected by a unique
55  *  prefix.  Currently defined subsystems are:
56  *
57  *  netmap 		(no id allowed)
58  *  			the standard subsystem
59  *
60  *  vale 		(followed by a possibly empty id)
61  *  			the vpname is connected to a VALE switch identified by
62  *  			the id (an empty id selects the default switch)
63  *
64  *  The "vpname" has the following syntax:
65  *
66  *     identifier			or
67  *     identifier1{identifier2		or
68  *     identifier1}identifier2
69  *
70  *  Identifiers are sequences of alphanumeric characters. The part that begins
71  *  with either '{' or '}', when present, denotes a netmap pipe opened in the
72  *  same memory region as the subsystem:indentifier1 port.
73  *
74  * The "mode" can be one of the following:
75  *
76  *	^		bind all host (sw) ring pairs
77  *	^NN		bind individual host ring pair
78  *	*		bind host and NIC ring pairs
79  *	-NN		bind individual NIC ring pair
80  *	@NN		open the port in the NN memory region
81  *	a suffix starting with / and the following flags,
82  *	in any order:
83  *	x		exclusive access
84  *	z		zero copy monitor (both tx and rx)
85  *	t		monitor tx side (copy monitor)
86  *	r		monitor rx side (copy monitor)
87  *	R		bind only RX ring(s)
88  *	T		bind only TX ring(s)
89  *
90  *  The "options" start at the first '@' character not followed by a number.
91  *  Each option starts with '@' and has the following syntax:
92  *
93  *      option					(flag option)
94  *      option=value				(single key option)
95  *      option:key1=value1,key2=value2,...	(multi-key option)
96  *
97  *  For multi-key options, the keys can be assigned in any order, but they
98  *  cannot be assigned more than once. It is not necessary to assign all the
99  *  option keys: unmentioned keys will receive default values.  Some multi-key
100  *  options define a default key and also accept the single-key syntax, by
101  *  assigning the value to this key.
102  *
103  *  NOTE: Options may be silently ignored if the port is already open by some
104  *  other process.
105  *
106  *  The currently available options are (default keys, when defined, are marked
107  *  with '*'):
108  *
109  *  share (single-key)
110  *  			open the port in the same memory region used by the
111  *  			given port name (the port name must be given in
112  *  			subsystem:vpname form)
113  *
114  *  conf  (multi-key)
115  *  			specify the rings/slots numbers (effective only on
116  *  			ports that are created by the open operation itself,
117  *  			and ignored otherwise).
118  *
119  *			The keys are:
120  *
121  *  		       *rings		number of tx and rx rings
122  *  			tx-rings	number of tx rings
123  *  			rx-rings	number of rx rings
124  *			host-rings	number of tx and rx host rings
125  *  			host-tx-rings	number of host tx rings
126  *  			host-rx-rings	number of host rx rings
127  *  			slots		number of slots in each tx and rx
128  *  					ring
129  *  			tx-slots	number of slots in each tx ring
130  *  			rx-slots	number of slots in each rx ring
131  *
132  *  			(more specific keys override the less specific ones)
133  *			All keys default to zero if not assigned, and the
134  *			corresponding value will be chosen by netmap.
135  *
136  *  extmem (multi-key)
137  *			open the port in the memory region obtained by
138  *			mmap()ing the given file.
139  *
140  *			The keys are:
141  *
142  *		       *file		the file to mmap
143  *			if-num		number of pre-allocated netmap_if's
144  *			if-size		size of each netmap_if
145  *			ring-num	number of pre-allocated netmap_ring's
146  *			ring-size	size of each netmap_ring
147  *			buf-num		number of pre-allocated buffers
148  *			buf-size	size of each buffer
149  *
150  *			file must be assigned. The other keys default to zero,
151  *			causing netmap to take the corresponding values from
152  *			the priv_{if,ring,buf}_{num,size} sysctls.
153  *
154  *  offset (multi-key)
155  *			reserve (part of) the ptr fields as an offset field
156  *			and write an initial offset into them.
157  *
158  *			The keys are:
159  *
160  *		        bits		number of bits of ptr to use
161  *		       *initial		initial offset value
162  *
163  *		        initial must be assigned. If bits is omitted, it
164  *		        defaults to the entire ptr field. The max offset is set
165  *		        at the same value as the initial offset. Note that the
166  *		        actual values may be increased by the kernel.
167  *
168  *		        This option is disabled by default (see
169  *			nmport_enable_option() below)
170  */
171 
172 
173 /* nmport manipulation */
174 
175 /* struct nmport_d - describes a netmap port */
176 struct nmport_d {
177 	/* see net/netmap.h for the definition of these fields */
178 	struct nmreq_header hdr;
179 	struct nmreq_register reg;
180 
181 	/* all the fields below should be considered read-only */
182 
183 	/* if the same context is used throughout the program, d1->mem ==
184 	 * d2->mem iff d1 and d2 are using the memory region (i.e., zero
185 	 * copy is possible between the two ports)
186 	 */
187 	struct nmem_d *mem;
188 
189 	/* the nmctx used when this nmport_d was created */
190 	struct nmctx *ctx;
191 
192 	int register_done;	/* nmport_register() has been called */
193 	int mmap_done;		/* nmport_mmap() has been called */
194 	/* pointer to the extmem option contained in the hdr options, if any */
195 	struct nmreq_opt_extmem *extmem;
196 
197 	/* the fields below are compatible with nm_open() */
198 	int fd;				/* "/dev/netmap", -1 if not open */
199 	struct netmap_if *nifp;		/* pointer to the netmap_if */
200 	uint16_t first_tx_ring;
201 	uint16_t last_tx_ring;
202 	uint16_t first_rx_ring;
203 	uint16_t last_rx_ring;
204 	uint16_t cur_tx_ring;		/* used by nmport_inject */
205 	uint16_t cur_rx_ring;
206 
207 	/* LIFO list of cleanup functions (used internally) */
208 	struct nmport_cleanup_d *clist;
209 };
210 
211 /* nmport_open - opens a port from a portspec
212  * @portspec	the port opening specification
213  *
214  * If successful, the function returns a new nmport_d describing a netmap
215  * port, opened according to the port specification, ready to be used for rx
216  * and/or tx.
217  *
218  * The rings available for tx are in the [first_tx_ring, last_tx_ring]
219  * interval, and similarly for rx. One or both intervals may be empty.
220  *
221  * When done using it, the nmport_d descriptor must be closed using
222  * nmport_close().
223  *
224  * In case of error, NULL is returned, errno is set to some error, and an
225  * error message is sent through the error() method of the current context.
226  */
227 struct nmport_d * nmport_open(const char *portspec);
228 
229 /* nport_close - close a netmap port
230  * @d		the port we want to close
231  *
232  * Undoes the actions performed by the nmport_open that created d, then
233  * frees the descriptor.
234  */
235 void nmport_close(struct nmport_d *d);
236 
237 /* nmport_inject - sends a packet
238  * @d		the port through which we want to send
239  * @buf		base address of the packet
240  * @size	its size in bytes
241  *
242  * Sends a packet using the cur_tx_ring and updates the index
243  * to use all available tx rings in turn. Note: the packet is copied.
244  *
245  * Returns 0 on success an -1 on error.
246  */
247 int nmport_inject(struct nmport_d *d, const void *buf, size_t size);
248 
249 /*
250  * the functions below can be used to split the functionality of
251  * nmport_open when special features (e.g., extra buffers) are needed
252  *
253  * The relation among the functions is as follows:
254  *
255  *				   |nmport_new
256  * 		|nmport_prepare	 = |
257  *		|		   |nmport_parse
258  * nmport_open =|
259  *		|		   |nmport_register
260  *		|nmport_open_desc =|
261  *				   |nmport_mmap
262  *
263  */
264 
265 /* nmport_new - create a new nmport_d
266  *
267  * Creates a new nmport_d using the malloc() method of the current default
268  * context. Returns NULL on error, setting errno to an error value.
269  */
270 struct nmport_d *nmport_new(void);
271 
272 /* nmport_parse - fills the nmport_d netmap-register request
273  * @d		the nmport to be filled
274  * @portspec	the port opening specification
275  *
276  * This function parses the portspec and initizalizes the @d->hdr and @d->reg
277  * fields. It may need to allocate a list of options. If an extmem option is
278  * found, it may also mmap() the corresponding file.
279  *
280  * It returns 0 on success. On failure it returns -1, sets errno to an error
281  * value and sends an error message to the error() method of the context used
282  * when @d was created. Moreover, *@d is left unchanged.
283  */
284 int nmport_parse(struct nmport_d *d, const char *portspec);
285 
286 /* nmport_register - registers the port with netmap
287  * @d		the nmport to be registered
288  *
289  * This function obtains a netmap file descriptor and registers the port with
290  * netmap. The @d->hdr and @d->reg data structures must have been previously
291  * initialized (via nmport_parse() or otherwise).
292  *
293  * It returns 0 on success. On failure it returns -1, sets errno to an error
294  * value and sends an error message to the error() method of the context used
295  * when @d was created. Moreover, *@d is left unchanged.
296  */
297 int nmport_register(struct nmport_d *);
298 
299 /* nmport_mmap - maps the port resources into the process memory
300  * @d		the nmport to be mapped
301  *
302  * The port must have been previously been registered using nmport_register.
303  *
304  * Note that if extmem is used (either via an option or by calling an
305  * nmport_extmem_* function before nmport_register()), no new mmap() is issued.
306  *
307  * It returns 0 on success. On failure it returns -1, sets errno to an error
308  * value and sends an error message to the error() method of the context used
309  * when @d was created. Moreover, *@d is left unchanged.
310  */
311 int nmport_mmap(struct nmport_d *);
312 
313 /* the following functions undo the actions of nmport_new(), nmport_parse(),
314  * nmport_register() and nmport_mmap(), respectively.
315  */
316 void nmport_delete(struct nmport_d *);
317 void nmport_undo_parse(struct nmport_d *);
318 void nmport_undo_register(struct nmport_d *);
319 void nmport_undo_mmap(struct nmport_d *);
320 
321 /* nmport_prepare - create a port descriptor, but do not open it
322  * @portspec	the port opening specification
323  *
324  * This functions creates a new nmport_d and initializes it according to
325  * @portspec. It is equivalent to nmport_new() followed by nmport_parse().
326  *
327  * It returns 0 on success. On failure it returns -1, sets errno to an error
328  * value and sends an error message to the error() method of the context used
329  * when @d was created. Moreover, *@d is left unchanged.
330  */
331 struct nmport_d *nmport_prepare(const char *portspec);
332 
333 /* nmport_open_desc - open an initialized port descriptor
334  * @d		the descriptor we want to open
335  *
336  * Registers the port with netmap and maps the rings and buffers into the
337  * process memory. It is equivalent to nmport_register() followed by
338  * nmport_mmap().
339  *
340  * It returns 0 on success. On failure it returns -1, sets errno to an error
341  * value and sends an error message to the error() method of the context used
342  * when @d was created. Moreover, *@d is left unchanged.
343  */
344 int nmport_open_desc(struct nmport_d *d);
345 
346 /* the following functions undo the actions of nmport_prepare()
347  * and nmport_open_desc(), respectively.
348  */
349 void nmport_undo_prepare(struct nmport_d *);
350 void nmport_undo_open_desc(struct nmport_d *);
351 
352 /* nmport_clone - copy an nmport_d
353  * @d		the nmport_d we want to copy
354  *
355  * Copying an nmport_d by hand should be avoided, since adjustments are needed
356  * and some part of the state cannot be easily duplicated. This function
357  * creates a copy of @d in a safe way. The returned nmport_d contains
358  * nmreq_header and nmreq_register structures equivalent to those contained in
359  * @d, except for the option list, which is ignored. The returned nmport_d is
360  * already nmport_prepare()d, but it must still be nmport_open_desc()ed. The
361  * new nmport_d uses the same nmctx as @d.
362  *
363  * If extmem was used for @d, then @d cannot be nmport_clone()d until it has
364  * been nmport_register()ed.
365  *
366  * In case of error, the function returns NULL, sets errno to an error value
367  * and sends an error message to the nmctx error() method.
368  */
369 struct nmport_d *nmport_clone(struct nmport_d *);
370 
371 /* nmport_extmem - use extmem for this port
372  * @d		the port we want to use the extmem for
373  * @base	the base address of the extmem region
374  * @size	the size in bytes of the extmem region
375  *
376  * the memory that contains the netmap ifs, rings and buffers is usually
377  * allocated by netmap and later mmap()ed by the applications. It is sometimes
378  * useful to reverse this process, by having the applications allocate some
379  * memory (through mmap() or otherwise) and then let netmap use it.  The extmem
380  * option can be used to implement this latter strategy. The option can be
381  * passed through the portspec using the '@extmem:...' syntax, or
382  * programmatically by calling nmport_extmem() or nmport_extmem_from_file()
383  * between nmport_parse() and nmport_register() (or between nmport_prepare()
384  * and nmport_open_desc()).
385  *
386  * It returns 0 on success. On failure it returns -1, sets errno to an error
387  * value and sends an error message to the error() method of the context used
388  * when @d was created. Moreover, *@d is left unchanged.
389  */
390 int nmport_extmem(struct nmport_d *d, void *base, size_t size);
391 
392 /* nmport_extmem_from_file - use the extmem obtained by mapping a file
393  * @d		the port we want to use the extmem for
394  * @fname	path of the file we want to map
395  *
396  * This works like nmport_extmem, but the extmem memory is obtained by
397  * mmap()ping @fname. nmport_close() will also automatically munmap() the file.
398  *
399  * It returns 0 on success. On failure it returns -1, sets errno to an error
400  * value and sends an error message to the error() method of the context used
401  * when @d was created. Moreover, *@d is left unchanged.
402  */
403 int nmport_extmem_from_file(struct nmport_d *d, const char *fname);
404 
405 /* nmport_extmem_getinfo - opbtai a pointer to the extmem configuration
406  * @d		the port we want to obtain the pointer from
407  *
408  * Returns a pointer to the nmreq_pools_info structure containing the
409  * configuration of the extmem attached to port @d, or NULL if no extmem
410  * is attached. This can be used to set the desired configuration before
411  * registering the port, or to read the actual configuration after
412  * registration.
413  */
414 struct nmreq_pools_info* nmport_extmem_getinfo(struct nmport_d *d);
415 
416 
417 /* nmport_offset - use offsets for this port
418  * @initial	the initial offset for all the slots
419  * @maxoff	the maximum offset
420  * @bits	the number of bits of slot->ptr to use for the offsets
421  * @mingap	the minimum gap between offsets (in shared buffers)
422  *
423  * With this option the lower @bits bits of the ptr field in the netmap_slot
424  * can be used to specify an offset into the buffer.  All offsets will be set
425  * to the @initial value by netmap.
426  *
427  * The offset field can be read and updated using the bitmask found in
428  * ring->offset_mask after a successful register.  netmap_user.h contains
429  * some helper macros (NETMAP_ROFFSET, NETMAP_WOFFSET and NETMAP_BUF_OFFSET).
430  *
431  * For RX rings, the user writes the offset o in an empty slot before passing
432  * it to netmap; then, netmap will write the incoming packet at an offset o' >=
433  * o in the buffer. o' may be larger than o because of, e.g., alignment
434  * constrains.  If o' > o netmap will also update the offset field in the slot.
435  * Note that large offsets may cause the port to split the packet over several
436  * slots, setting the NS_MOREFRAG flag accordingly.
437  *
438  * For TX rings, the user may prepare the packet to send at an offset o into
439  * the buffer and write o in the offset field. Netmap will send the packets
440  * starting o bytes in the buffer. Note that the address of the packet must
441  * comply with any alignment constraints that the port may have, or the result
442  * will be undefined. The user may read the alignment constraint in the new
443  * ring->buf_align field.  It is also possible that empty slots already come
444  * with a non-zero offset o specified in the offset field. In this case, the
445  * user will have to write the packet at an offset o' >= o.
446  *
447  * The user must also declare the @maxoff offset that she is going to use. Any
448  * offset larger than this will be truncated.
449  *
450  * The user may also declare a @mingap (ignored if zero) if she plans to use
451  * offsets to share the same buffer among several slots. Netmap will guarantee
452  * that it will never write more than @mingap bytes for each slot, irrespective
453  * of the buffer length.
454  */
455 int nmport_offset(struct nmport_d *d, uint64_t initial, uint64_t maxoff,
456 		uint64_t bits, uint64_t mingap);
457 
458 /* enable/disable options
459  *
460  * These functions can be used to disable options that the application cannot
461  * or doesn't want to handle, or to enable options that require special support
462  * from the application and are, therefore, disabled by default. Disabled
463  * options will cause an error if encountered during option parsing.
464  *
465  * If the option is unknown, nmport_disable_option is a NOP, while
466  * nmport_enable_option returns -1 and sets errno to EOPNOTSUPP.
467  *
468  * These functions are not threadsafe and are meant to be used at the beginning
469  * of the program.
470  */
471 void nmport_disable_option(const char *opt);
472 int nmport_enable_option(const char *opt);
473 
474 /* nmreq manipulation
475  *
476  * nmreq_header_init - initialize an nmreq_header
477  * @hdr		the nmreq_header to initialize
478  * @reqtype	the kind of netmap request
479  * @body	the body of the request
480  *
481  * Initialize the nr_version, nr_reqtype and nr_body fields of *@hdr.
482  * The other fields are set to zero.
483  */
484 void nmreq_header_init(struct nmreq_header *hdr, uint16_t reqtype, void *body);
485 
486 /*
487  * These functions allow for finer grained parsing of portspecs.  They are used
488  * internally by nmport_parse().
489  */
490 
491 /* nmreq_header_decode - initialize an nmreq_header
492  * @ppspec:	(in/out) pointer to a pointer to the portspec
493  * @hdr:	pointer to the nmreq_header to be initialized
494  * @ctx:	pointer to the nmctx to use (for errors)
495  *
496  * This function fills the @hdr the nr_name field with the port name extracted
497  * from *@pifname.  The other fields of *@hdr are unchanged. The @pifname is
498  * updated to point at the first char past the port name.
499  *
500  * Returns 0 on success.  In case of error, -1 is returned with errno set to
501  * EINVAL, @pifname is unchanged, *@hdr is also unchanged, and an error message
502  * is sent through @ctx->error().
503  */
504 int nmreq_header_decode(const char **ppspec, struct nmreq_header *hdr,
505 		struct nmctx *ctx);
506 
507 /* nmreq_regiter_decode - initialize an nmreq_register
508  * @pmode:	(in/out) pointer to a pointer to an opening mode
509  * @reg:	pointer to the nmreq_register to be initialized
510  * @ctx:	pointer to the nmctx to use (for errors)
511  *
512  * This function fills the nr_mode, nr_ringid, nr_flags and nr_mem_id fields of
513  * the structure pointed by @reg, according to the opening mode specified by
514  * *@pmode. The other fields of *@reg are unchanged.  The @pmode is updated to
515  * point at the first char past the opening mode.
516  *
517  * If a '@' is encountered followed by something which is not a number, parsing
518  * stops (without error) and @pmode is left pointing at the '@' char. The
519  * nr_mode, nr_ringid and nr_flags fields are still updated, but nr_mem_id is
520  * not touched and the interpretation of the '@' field is left to the caller.
521  *
522  * Returns 0 on success.  In case of error, -1 is returned with errno set to
523  * EINVAL, @pmode is unchanged, *@reg is also unchanged, and an error message
524  * is sent through @ctx->error().
525  */
526 int nmreq_register_decode(const char **pmode, struct nmreq_register *reg,
527 		struct nmctx *ctx);
528 
529 /* nmreq_options_decode - parse the "options" part of the portspec
530  * @opt:	pointer to the option list
531  * @parsers:	list of option parsers
532  * @token:	token to pass to each parser
533  * @ctx:	pointer to the nmctx to use (for errors and malloc/free)
534  *
535  * This function parses each option in @opt. Each option is matched (based on
536  * the "option" prefix) to a corresponding parser in @parsers. The function
537  * checks that the syntax is appropriate for the parser and it assigns all the
538  * keys mentioned in the option. It then passes control to the parser, to
539  * interpret the keys values.
540  *
541  * Returns 0 on success. In case of error, -1 is returned, errno is set to an
542  * error value and a message is sent to @ctx->error(). The effects of partially
543  * interpreted options may not be undone.
544  */
545 struct nmreq_opt_parser;
546 int nmreq_options_decode(const char *opt, struct nmreq_opt_parser *parsers,
547 		void *token, struct nmctx *ctx);
548 
549 struct nmreq_parse_ctx;
550 /* type of the option-parsers callbacks */
551 typedef int (*nmreq_opt_parser_cb)(struct nmreq_parse_ctx *);
552 
553 #define NMREQ_OPT_MAXKEYS 16	/* max nr of recognized keys per option */
554 
555 /* struct nmreq_opt_key - describes an option key */
556 struct nmreq_opt_key {
557 	const char *key;	/* the key name */
558 	int id;			/* its position in the parse context */
559 	unsigned int flags;
560 #define NMREQ_OPTK_ALLOWEMPTY 	(1U << 0) /* =value may be omitted */
561 #define NMREQ_OPTK_MUSTSET	(1U << 1) /* the key is mandatory */
562 #define NMREQ_OPTK_DEFAULT	(1U << 2) /* this is the default key */
563 };
564 
565 /* struct nmreq_opt_parser - describes an option parser */
566 struct nmreq_opt_parser {
567 	const char *prefix;	/* matches one option prefix */
568 	nmreq_opt_parser_cb parse;	/* the parse callback */
569 	int default_key;	/* which option is the default if the
570 				   parser is multi-key (-1 if none) */
571 	int nr_keys;
572 	unsigned int flags;
573 #define NMREQ_OPTF_DISABLED     (1U << 0)
574 #define NMREQ_OPTF_ALLOWEMPTY	(1U << 1)	/* =value can be omitted */
575 
576 	struct nmreq_opt_parser *next;	/* list of options */
577 
578 	/* recognized keys */
579 	struct nmreq_opt_key keys[NMREQ_OPT_MAXKEYS];
580 } __attribute__((aligned(16)));
581 
582 /* struct nmreq_parse_ctx - the parse context received by the parse callback */
583 struct nmreq_parse_ctx {
584 	struct nmctx *ctx;	/* the nmctx for errors and malloc/free */
585 	void *token;		/* the token passed to nmreq_options_parse */
586 
587 	/* the value (i.e., the part after the = sign) of each recognized key
588 	 * is assigned to the corresponding entry in this array, based on the
589 	 * key id. Unassigned keys are left at NULL.
590 	 */
591 	const char *keys[NMREQ_OPT_MAXKEYS];
592 };
593 
594 /* nmreq_get_mem_id - get the mem_id of the given port
595  * @portname	pointer to a pointer to the portname
596  * @ctx		pointer to the nmctx to use (for errors)
597  *
598  * *@portname must point to a substem:vpname porname, possibly followed by
599  * something else.
600  *
601  * If successful, returns the mem_id of *@portname and moves @portname past the
602  * subsystem:vpname part of the input. In case of error it returns -1, sets
603  * errno to an error value and sends an error message to ctx->error().
604  */
605 int32_t nmreq_get_mem_id(const char **portname, struct nmctx *ctx);
606 
607 /* option list manipulation */
608 void nmreq_push_option(struct nmreq_header *, struct nmreq_option *);
609 void nmreq_remove_option(struct nmreq_header *, struct nmreq_option *);
610 struct nmreq_option *nmreq_find_option(struct nmreq_header *, uint32_t);
611 void nmreq_free_options(struct nmreq_header *);
612 const char* nmreq_option_name(uint32_t);
613 #define nmreq_foreach_option(h_, o_) \
614 	for ((o_) = (struct nmreq_option *)((uintptr_t)((h_)->nr_options));\
615 	     (o_) != NULL;\
616 	     (o_) = (struct nmreq_option *)((uintptr_t)((o_)->nro_next)))
617 
618 /* nmctx manipulation */
619 
620 /* the nmctx serves a few purposes:
621  *
622  * - maintain a list of all memory regions open by the program, so that two
623  *   ports that are using the same region (as identified by the mem_id) will
624  *   point to the same nmem_d instance.
625  *
626  * - allow the user to specify how to lock accesses to the above list, if
627  *   needed (lock() callback)
628  *
629  * - allow the user to specify how error messages should be delivered (error()
630  *   callback)
631  *
632  * - select the verbosity of the library (verbose field); if verbose==0, no
633  *   errors are sent to the error() callback
634  *
635  * - allow the user to override the malloc/free functions used by the library
636  *   (malloc() and free() callbacks)
637  *
638  */
639 typedef void  (*nmctx_error_cb)(struct nmctx *, const char *);
640 typedef void *(*nmctx_malloc_cb)(struct nmctx *,size_t);
641 typedef void  (*nmctx_free_cb)(struct nmctx *,void *);
642 typedef void  (*nmctx_lock_cb)(struct nmctx *, int);
643 
644 struct nmctx {
645 	int verbose;
646 	nmctx_error_cb 	error;
647 	nmctx_malloc_cb	malloc;
648 	nmctx_free_cb	free;
649 	nmctx_lock_cb	lock;
650 
651 	struct nmem_d  *mem_descs;
652 };
653 
654 /* nmctx_get - obtain a pointer to the current default context */
655 struct nmctx *nmctx_get(void);
656 
657 /* nmctx_set_default - change the default context
658  * @ctx		pointer to the new context
659  *
660  * Returns a pointer to the previous default context.
661  */
662 struct nmctx *nmctx_set_default(struct nmctx *ctx);
663 
664 /* internal functions and data structures */
665 
666 /* struct nmem_d - describes a memory region currently used */
667 struct nmem_d {
668 	uint16_t mem_id;	/* the region netmap identifier */
669 	int refcount;		/* how many nmport_d's point here */
670 	void *mem;		/* memory region base address */
671 	size_t size;		/* memory region size */
672 	int is_extmem;		/* was it obtained via extmem? */
673 
674 	/* pointers for the circular list implementation.
675 	 * The list head is the mem_descs filed in the nmctx
676 	 */
677 	struct nmem_d *next;
678 	struct nmem_d *prev;
679 };
680 
681 /* a trick to force the inclusion of libpthread only if requested. If
682  * LIBNETMAP_NOTHREADSAFE is defined, no pthread symbol is imported.
683  *
684  * There is no need to actually call this function: the ((used)) attribute is
685  * sufficient to include it in the image.
686  */
687 static  __attribute__((used)) void libnetmap_init(void)
688 {
689 #ifndef LIBNETMAP_NOTHREADSAFE
690 	extern int nmctx_threadsafe;
691 	/* dummy assignment to link-in the nmctx-pthread.o object.  The proper
692 	 * inizialization is performed only once in the library constructor
693 	 * defined there.
694 	 */
695 	nmctx_threadsafe = 1;
696 #endif /* LIBNETMAP_NOTHREADSAFE */
697 }
698 
699 /* nmctx_set_threadsafe - install a threadsafe default context
700  *
701  * called by the constructor in nmctx-pthread.o to initialize a lock and install
702  * the lock() callback in the default context.
703  */
704 void nmctx_set_threadsafe(void);
705 
706 /* nmctx_ferror - format and send an error message */
707 void nmctx_ferror(struct nmctx *, const char *, ...);
708 /* nmctx_malloc - allocate memory */
709 void *nmctx_malloc(struct nmctx *, size_t);
710 /* nmctx_free - free memory allocated via nmctx_malloc */
711 void nmctx_free(struct nmctx *, void *);
712 /* nmctx_lock - lock the list of nmem_d */
713 void nmctx_lock(struct nmctx *);
714 /* nmctx_unlock - unlock the list of nmem_d */
715 void nmctx_unlock(struct nmctx *);
716 
717 #endif /* LIBNETMAP_H_ */
718