Line data Source code
1 : /*
2 : * Packet interface
3 : * Copyright (C) 1999 Kunihiro Ishiguro
4 : *
5 : * This file is part of GNU Zebra.
6 : *
7 : * GNU Zebra is free software; you can redistribute it and/or modify it
8 : * under the terms of the GNU General Public License as published by the
9 : * Free Software Foundation; either version 2, or (at your option) any
10 : * later version.
11 : *
12 : * GNU Zebra is distributed in the hope that it will be useful, but
13 : * WITHOUT ANY WARRANTY; without even the implied warranty of
14 : * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 : * General Public License for more details.
16 : *
17 : * You should have received a copy of the GNU General Public License along
18 : * with this program; see the file COPYING; if not, write to the Free Software
19 : * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20 : */
21 :
22 : #ifndef _ZEBRA_STREAM_H
23 : #define _ZEBRA_STREAM_H
24 :
25 : #include <pthread.h>
26 :
27 : #include "frratomic.h"
28 : #include "mpls.h"
29 : #include "prefix.h"
30 :
31 : #ifdef __cplusplus
32 : extern "C" {
33 : #endif
34 :
35 : /*
36 : * A stream is an arbitrary buffer, whose contents generally are assumed to
37 : * be in network order.
38 : *
39 : * A stream has the following attributes associated with it:
40 : *
41 : * - size: the allocated, invariant size of the buffer.
42 : *
43 : * - getp: the get position marker, denoting the offset in the stream where
44 : * the next read (or 'get') will be from. This getp marker is
45 : * automatically adjusted when data is read from the stream, the
46 : * user may also manipulate this offset as they wish, within limits
47 : * (see below)
48 : *
49 : * - endp: the end position marker, denoting the offset in the stream where
50 : * valid data ends, and if the user attempted to write (or
51 : * 'put') data where that data would be written (or 'put') to.
52 : *
53 : * These attributes are all size_t values.
54 : *
55 : * Constraints:
56 : *
57 : * 1. getp can never exceed endp
58 : *
59 : * - hence if getp is equal to endp, there is no more valid data that can be
60 : * gotten from the stream (though, the user may reposition getp to earlier in
61 : * the stream, if they wish).
62 : *
63 : * 2. endp can never exceed size
64 : *
65 : * - hence, if endp is equal to size, then the stream is full, and no more
66 : * data can be written to the stream.
67 : *
68 : * In other words the following must always be true, and the stream
69 : * abstraction is allowed internally to assert that the following property
70 : * holds true for a stream, as and when it wishes:
71 : *
72 : * getp <= endp <= size
73 : *
74 : * It is the users responsibility to ensure this property is never violated.
75 : *
76 : * A stream therefore can be thought of like this:
77 : *
78 : * ---------------------------------------------------
79 : * |XXXXXXXXXXXXXXXXXXXXXXXX |
80 : * ---------------------------------------------------
81 : * ^ ^ ^
82 : * getp endp size
83 : *
84 : * This shows a stream containing data (shown as 'X') up to the endp offset.
85 : * The stream is empty from endp to size. Without adjusting getp, there are
86 : * still endp-getp bytes of valid data to be read from the stream.
87 : *
88 : * Methods are provided to get and put to/from the stream, as well as
89 : * retrieve the values of the 3 markers and manipulate the getp marker.
90 : *
91 : * Note:
92 : * At the moment, newly allocated streams are zero filled. Hence, one can
93 : * use stream_forward_endp() to effectively create arbitrary zero-fill
94 : * padding. However, note that stream_reset() does *not* zero-out the
95 : * stream. This property should **not** be relied upon.
96 : *
97 : * Best practice is to use stream_put (<stream *>, NULL, <size>) to zero out
98 : * any part of a stream which isn't otherwise written to.
99 : */
100 :
101 : /* Stream buffer. */
102 : struct stream {
103 : struct stream *next;
104 :
105 : /*
106 : * Remainder is ***private*** to stream
107 : * direct access is frowned upon!
108 : * Use the appropriate functions/macros
109 : */
110 : size_t getp; /* next get position */
111 : size_t endp; /* last valid data position */
112 : size_t size; /* size of data segment */
113 : unsigned char data[]; /* data pointer */
114 : };
115 :
116 : /* First in first out queue structure. */
117 : struct stream_fifo {
118 : /* lock for mt-safe operations */
119 : pthread_mutex_t mtx;
120 :
121 : /* number of streams in this fifo */
122 : atomic_size_t count;
123 : #if defined DEV_BUILD
124 : atomic_size_t max_count;
125 : #endif
126 :
127 : struct stream *head;
128 : struct stream *tail;
129 : };
130 :
131 : /* Utility macros. */
132 : #define STREAM_SIZE(S) ((S)->size)
133 : /* number of bytes which can still be written */
134 : #define STREAM_WRITEABLE(S) ((S)->size - (S)->endp)
135 : /* number of bytes still to be read */
136 : #define STREAM_READABLE(S) ((S)->endp - (S)->getp)
137 :
138 : #define STREAM_CONCAT_REMAIN(S1, S2, size) ((size) - (S1)->endp - (S2)->endp)
139 :
140 : /* this macro is deprecated, but not slated for removal anytime soon */
141 : #define STREAM_DATA(S) ((S)->data)
142 :
143 : /* Stream prototypes.
144 : * For stream_{put,get}S, the S suffix mean:
145 : *
146 : * c: character (unsigned byte)
147 : * w: word (two bytes)
148 : * l: long (two words)
149 : * q: quad (four words)
150 : */
151 : extern struct stream *stream_new(size_t);
152 : extern void stream_free(struct stream *);
153 : /* Copy 'src' into 'dest', returns 'dest' */
154 : extern struct stream *stream_copy(struct stream *dest,
155 : const struct stream *src);
156 : extern struct stream *stream_dup(const struct stream *s);
157 :
158 : extern size_t stream_resize_inplace(struct stream **sptr, size_t newsize);
159 :
160 : extern size_t stream_get_getp(const struct stream *s);
161 : extern size_t stream_get_endp(const struct stream *s);
162 : extern size_t stream_get_size(const struct stream *s);
163 :
164 : /**
165 : * Create a new stream structure; copy offset bytes from s1 to the new
166 : * stream; copy s2 data to the new stream; copy rest of s1 data to the
167 : * new stream.
168 : */
169 : extern struct stream *stream_dupcat(const struct stream *s1,
170 : const struct stream *s2, size_t offset);
171 :
172 : extern void stream_set_getp(struct stream *, size_t);
173 : extern void stream_set_endp(struct stream *, size_t);
174 : extern void stream_forward_getp(struct stream *, size_t);
175 : extern bool stream_forward_getp2(struct stream *, size_t);
176 : extern void stream_rewind_getp(struct stream *s, size_t size);
177 : extern bool stream_rewind_getp2(struct stream *s, size_t size);
178 : extern void stream_forward_endp(struct stream *, size_t);
179 : extern bool stream_forward_endp2(struct stream *, size_t);
180 :
181 : /* steam_put: NULL source zeroes out size_t bytes of stream */
182 : extern void stream_put(struct stream *, const void *, size_t);
183 : extern int stream_putc(struct stream *, uint8_t);
184 : extern int stream_putc_at(struct stream *, size_t, uint8_t);
185 : extern int stream_putw(struct stream *, uint16_t);
186 : extern int stream_putw_at(struct stream *, size_t, uint16_t);
187 : extern int stream_put3(struct stream *, uint32_t);
188 : extern int stream_put3_at(struct stream *, size_t, uint32_t);
189 : extern int stream_putl(struct stream *, uint32_t);
190 : extern int stream_putl_at(struct stream *, size_t, uint32_t);
191 : extern int stream_putq(struct stream *, uint64_t);
192 : extern int stream_putq_at(struct stream *, size_t, uint64_t);
193 : extern int stream_put_ipv4(struct stream *, uint32_t);
194 : extern int stream_put_in_addr(struct stream *s, const struct in_addr *addr);
195 : extern bool stream_put_ipaddr(struct stream *s, struct ipaddr *ip);
196 : extern int stream_put_in_addr_at(struct stream *s, size_t putp,
197 : const struct in_addr *addr);
198 : extern int stream_put_in6_addr_at(struct stream *s, size_t putp,
199 : const struct in6_addr *addr);
200 : extern int stream_put_prefix_addpath(struct stream *s, const struct prefix *p,
201 : bool addpath_capable,
202 : uint32_t addpath_tx_id);
203 : extern int stream_put_prefix(struct stream *s, const struct prefix *p);
204 : extern int stream_put_labeled_prefix(struct stream *, const struct prefix *,
205 : mpls_label_t *, bool addpath_capable,
206 : uint32_t addpath_tx_id);
207 : extern void stream_get(void *, struct stream *, size_t);
208 : extern bool stream_get2(void *data, struct stream *s, size_t size);
209 : extern void stream_get_from(void *, struct stream *, size_t, size_t);
210 : extern uint8_t stream_getc(struct stream *);
211 : extern bool stream_getc2(struct stream *s, uint8_t *byte);
212 : extern uint8_t stream_getc_from(struct stream *, size_t);
213 : extern uint16_t stream_getw(struct stream *);
214 : extern bool stream_getw2(struct stream *s, uint16_t *word);
215 : extern uint16_t stream_getw_from(struct stream *, size_t);
216 : extern uint32_t stream_get3(struct stream *);
217 : extern uint32_t stream_get3_from(struct stream *, size_t);
218 : extern uint32_t stream_getl(struct stream *);
219 : extern bool stream_getl2(struct stream *s, uint32_t *l);
220 : extern uint32_t stream_getl_from(struct stream *, size_t);
221 : extern uint64_t stream_getq(struct stream *);
222 : extern uint64_t stream_getq_from(struct stream *, size_t);
223 : bool stream_getq2(struct stream *s, uint64_t *q);
224 : extern uint32_t stream_get_ipv4(struct stream *);
225 : extern bool stream_get_ipaddr(struct stream *s, struct ipaddr *ip);
226 :
227 : /* IEEE-754 floats */
228 : extern float stream_getf(struct stream *);
229 : extern double stream_getd(struct stream *);
230 : extern int stream_putf(struct stream *, float);
231 : extern int stream_putd(struct stream *, double);
232 :
233 : #undef stream_read
234 : #undef stream_write
235 :
236 : /* Deprecated: assumes blocking I/O. Will be removed.
237 : Use stream_read_try instead. */
238 : extern int stream_read(struct stream *, int, size_t);
239 :
240 : /* Read up to size bytes into the stream.
241 : Return code:
242 : >0: number of bytes read
243 : 0: end-of-file
244 : -1: fatal error
245 : -2: transient error, should retry later (i.e. EAGAIN or EINTR)
246 : This is suitable for use with non-blocking file descriptors.
247 : */
248 : extern ssize_t stream_read_try(struct stream *s, int fd, size_t size);
249 :
250 : extern ssize_t stream_recvmsg(struct stream *s, int fd, struct msghdr *,
251 : int flags, size_t size);
252 : extern ssize_t stream_recvfrom(struct stream *s, int fd, size_t len, int flags,
253 : struct sockaddr *from, socklen_t *fromlen);
254 : extern size_t stream_write(struct stream *, const void *, size_t);
255 :
256 : /* reset the stream. See Note above */
257 : extern void stream_reset(struct stream *);
258 : extern int stream_flush(struct stream *, int);
259 : extern int stream_empty(struct stream *); /* is the stream empty? */
260 :
261 : /* debugging */
262 : extern void stream_hexdump(const struct stream *s);
263 :
264 : /**
265 : * Reorganize the buffer data so it can fit more. This function is normally
266 : * called right after stream data is consumed so we can read more data
267 : * (the functions that consume data start with `stream_get*()` and macros
268 : * `STREAM_GET*()`).
269 : *
270 : * \param s stream pointer.
271 : */
272 : extern void stream_pulldown(struct stream *s);
273 :
274 : /* deprecated */
275 : extern uint8_t *stream_pnt(struct stream *);
276 :
277 : /*
278 : * Operations on struct stream_fifo.
279 : *
280 : * Each function has a safe variant, which ensures that the operation performed
281 : * is atomic with respect to the operations performed by all other safe
282 : * variants. In other words, the safe variants lock the stream_fifo's mutex
283 : * before performing their action. These are provided for convenience when
284 : * using stream_fifo in a multithreaded context, to alleviate the need for the
285 : * caller to implement their own synchronization around the stream_fifo.
286 : *
287 : * The following functions do not have safe variants. The caller must ensure
288 : * that these operations are performed safely in a multithreaded context:
289 : * - stream_fifo_new
290 : * - stream_fifo_free
291 : */
292 :
293 : /*
294 : * Create a new stream_fifo.
295 : *
296 : * Returns:
297 : * newly created stream_fifo
298 : */
299 : extern struct stream_fifo *stream_fifo_new(void);
300 :
301 : /*
302 : * Init or re-init an on-stack fifo. This allows use of a fifo struct without
303 : * requiring a malloc/free cycle.
304 : * Note well that the fifo must be de-inited with the 'fifo_deinit' api.
305 : */
306 : void stream_fifo_init(struct stream_fifo *fifo);
307 :
308 : /*
309 : * Deinit an on-stack fifo.
310 : */
311 : void stream_fifo_deinit(struct stream_fifo *fifo);
312 :
313 : /*
314 : * Push a stream onto a stream_fifo.
315 : *
316 : * fifo
317 : * the stream_fifo to push onto
318 : *
319 : * s
320 : * the stream to push onto the stream_fifo
321 : */
322 : extern void stream_fifo_push(struct stream_fifo *fifo, struct stream *s);
323 : extern void stream_fifo_push_safe(struct stream_fifo *fifo, struct stream *s);
324 :
325 : /*
326 : * Pop a stream off a stream_fifo.
327 : *
328 : * fifo
329 : * the stream_fifo to pop from
330 : *
331 : * Returns:
332 : * the next stream in the stream_fifo
333 : */
334 : extern struct stream *stream_fifo_pop(struct stream_fifo *fifo);
335 : extern struct stream *stream_fifo_pop_safe(struct stream_fifo *fifo);
336 :
337 : /*
338 : * Retrieve the next stream from a stream_fifo without popping it.
339 : *
340 : * fifo
341 : * the stream_fifo to operate on
342 : *
343 : * Returns:
344 : * the next stream that would be returned from stream_fifo_pop
345 : */
346 : extern struct stream *stream_fifo_head(struct stream_fifo *fifo);
347 : extern struct stream *stream_fifo_head_safe(struct stream_fifo *fifo);
348 :
349 : /*
350 : * Remove all streams from a stream_fifo.
351 : *
352 : * fifo
353 : * the stream_fifo to clean
354 : */
355 : extern void stream_fifo_clean(struct stream_fifo *fifo);
356 : extern void stream_fifo_clean_safe(struct stream_fifo *fifo);
357 :
358 : /*
359 : * Retrieve number of streams on a stream_fifo.
360 : *
361 : * fifo
362 : * the stream_fifo to retrieve the count for
363 : *
364 : * Returns:
365 : * the number of streams on the stream_fifo
366 : */
367 : extern size_t stream_fifo_count_safe(struct stream_fifo *fifo);
368 :
369 : /*
370 : * Free a stream_fifo.
371 : *
372 : * Calls stream_fifo_clean, then deinitializes the stream_fifo and frees it.
373 : *
374 : * fifo
375 : * the stream_fifo to free
376 : */
377 : extern void stream_fifo_free(struct stream_fifo *fifo);
378 :
379 : /* This is here because "<< 24" is particularly problematic in C.
380 : * This is because the left operand of << is integer-promoted, which means
381 : * an uint8_t gets converted into a *signed* int. Shifting into the sign
382 : * bit of a signed int is theoretically undefined behaviour, so - the left
383 : * operand needs to be cast to unsigned.
384 : *
385 : * This is not a problem for 16- or 8-bit values (they don't reach the sign
386 : * bit), for 64-bit values (you need to cast them anyway), and neither for
387 : * encoding (because it's downcasted.)
388 : */
389 0 : static inline const uint8_t *ptr_get_be64(const uint8_t *ptr, uint64_t *out)
390 : {
391 0 : uint32_t tmp1, tmp2;
392 :
393 0 : memcpy(&tmp1, ptr, sizeof(tmp1));
394 0 : memcpy(&tmp2, ptr + sizeof(tmp1), sizeof(tmp1));
395 :
396 0 : *out = (((uint64_t)ntohl(tmp1)) << 32) | ntohl(tmp2);
397 :
398 0 : return ptr + 8;
399 : }
400 :
401 8 : static inline const uint8_t *ptr_get_be32(const uint8_t *ptr, uint32_t *out)
402 : {
403 8 : uint32_t tmp;
404 :
405 8 : memcpy(&tmp, ptr, sizeof(tmp));
406 8 : *out = ntohl(tmp);
407 8 : return ptr + 4;
408 : }
409 :
410 0 : static inline uint8_t *ptr_get_be16(uint8_t *ptr, uint16_t *out)
411 : {
412 0 : uint16_t tmp;
413 :
414 0 : memcpy(&tmp, ptr, sizeof(tmp));
415 0 : *out = ntohs(tmp);
416 :
417 0 : return ptr + 2;
418 : }
419 :
420 : /*
421 : * so Normal stream_getX functions assert. Which is anathema
422 : * to keeping a daemon up and running when something goes south
423 : * Provide a stream_getX2 functions that do not assert.
424 : * In addition provide these macro's that upon failure
425 : * goto stream_failure. This is modeled upon some NL_XX
426 : * macros in the linux kernel.
427 : *
428 : * This change allows for proper memory freeing
429 : * after we've detected an error.
430 : *
431 : * In the future we will be removing the assert in
432 : * the stream functions but we need a transition
433 : * plan.
434 : */
435 : #define STREAM_GETC(S, P) \
436 : do { \
437 : uint8_t _pval; \
438 : if (!stream_getc2((S), &_pval)) \
439 : goto stream_failure; \
440 : (P) = _pval; \
441 : } while (0)
442 :
443 : #define STREAM_GETW(S, P) \
444 : do { \
445 : uint16_t _pval; \
446 : if (!stream_getw2((S), &_pval)) \
447 : goto stream_failure; \
448 : (P) = _pval; \
449 : } while (0)
450 :
451 : #define STREAM_GETL(S, P) \
452 : do { \
453 : uint32_t _pval; \
454 : if (!stream_getl2((S), &_pval)) \
455 : goto stream_failure; \
456 : (P) = _pval; \
457 : } while (0)
458 :
459 : #define STREAM_GETF(S, P) \
460 : do { \
461 : union { \
462 : float r; \
463 : uint32_t d; \
464 : } _pval; \
465 : if (!stream_getl2((S), &_pval.d)) \
466 : goto stream_failure; \
467 : (P) = _pval.r; \
468 : } while (0)
469 :
470 : #define STREAM_GETQ(S, P) \
471 : do { \
472 : uint64_t _pval; \
473 : if (!stream_getq2((S), &_pval)) \
474 : goto stream_failure; \
475 : (P) = _pval; \
476 : } while (0)
477 :
478 : #define STREAM_GET_IPADDR(S, P) \
479 : do { \
480 : if (!stream_get_ipaddr((S), (P))) \
481 : goto stream_failure; \
482 : } while (0)
483 :
484 : #define STREAM_GET(P, STR, SIZE) \
485 : do { \
486 : if (!stream_get2((P), (STR), (SIZE))) \
487 : goto stream_failure; \
488 : } while (0)
489 :
490 : #define STREAM_FORWARD_GETP(STR, SIZE) \
491 : do { \
492 : if (!stream_forward_getp2((STR), (SIZE))) \
493 : goto stream_failure; \
494 : } while (0)
495 :
496 : #define STREAM_REWIND_GETP(STR, SIZE) \
497 : do { \
498 : if (!stream_rewind_getp2((STR), (SIZE))) \
499 : goto stream_failure; \
500 : } while (0)
501 :
502 : #define STREAM_FORWARD_ENDP(STR, SIZE) \
503 : do { \
504 : if (!stream_forward_endp2((STR), (SIZE))) \
505 : goto stream_failure; \
506 : } while (0)
507 :
508 : #ifdef __cplusplus
509 : }
510 : #endif
511 :
512 : #endif /* _ZEBRA_STREAM_H */
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