Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0-or-later
2 : /*
3 : * Packet interface
4 : * Copyright (C) 1999 Kunihiro Ishiguro
5 : */
6 :
7 : #ifndef _ZEBRA_STREAM_H
8 : #define _ZEBRA_STREAM_H
9 :
10 : #include <pthread.h>
11 :
12 : #include "frratomic.h"
13 : #include "mpls.h"
14 : #include "prefix.h"
15 :
16 : #ifdef __cplusplus
17 : extern "C" {
18 : #endif
19 :
20 : /*
21 : * A stream is an arbitrary buffer, whose contents generally are assumed to
22 : * be in network order.
23 : *
24 : * A stream has the following attributes associated with it:
25 : *
26 : * - size: the allocated, invariant size of the buffer.
27 : *
28 : * - getp: the get position marker, denoting the offset in the stream where
29 : * the next read (or 'get') will be from. This getp marker is
30 : * automatically adjusted when data is read from the stream, the
31 : * user may also manipulate this offset as they wish, within limits
32 : * (see below)
33 : *
34 : * - endp: the end position marker, denoting the offset in the stream where
35 : * valid data ends, and if the user attempted to write (or
36 : * 'put') data where that data would be written (or 'put') to.
37 : *
38 : * These attributes are all size_t values.
39 : *
40 : * Constraints:
41 : *
42 : * 1. getp can never exceed endp
43 : *
44 : * - hence if getp is equal to endp, there is no more valid data that can be
45 : * gotten from the stream (though, the user may reposition getp to earlier in
46 : * the stream, if they wish).
47 : *
48 : * 2. endp can never exceed size
49 : *
50 : * - hence, if endp is equal to size, then the stream is full, and no more
51 : * data can be written to the stream.
52 : *
53 : * In other words the following must always be true, and the stream
54 : * abstraction is allowed internally to assert that the following property
55 : * holds true for a stream, as and when it wishes:
56 : *
57 : * getp <= endp <= size
58 : *
59 : * It is the users responsibility to ensure this property is never violated.
60 : *
61 : * A stream therefore can be thought of like this:
62 : *
63 : * ---------------------------------------------------
64 : * |XXXXXXXXXXXXXXXXXXXXXXXX |
65 : * ---------------------------------------------------
66 : * ^ ^ ^
67 : * getp endp size
68 : *
69 : * This shows a stream containing data (shown as 'X') up to the endp offset.
70 : * The stream is empty from endp to size. Without adjusting getp, there are
71 : * still endp-getp bytes of valid data to be read from the stream.
72 : *
73 : * Methods are provided to get and put to/from the stream, as well as
74 : * retrieve the values of the 3 markers and manipulate the getp marker.
75 : *
76 : * Note:
77 : * At the moment, newly allocated streams are zero filled. Hence, one can
78 : * use stream_forward_endp() to effectively create arbitrary zero-fill
79 : * padding. However, note that stream_reset() does *not* zero-out the
80 : * stream. This property should **not** be relied upon.
81 : *
82 : * Best practice is to use stream_put (<stream *>, NULL, <size>) to zero out
83 : * any part of a stream which isn't otherwise written to.
84 : */
85 :
86 : /* Stream buffer. */
87 : struct stream {
88 : struct stream *next;
89 :
90 : /*
91 : * Remainder is ***private*** to stream
92 : * direct access is frowned upon!
93 : * Use the appropriate functions/macros
94 : */
95 : size_t getp; /* next get position */
96 : size_t endp; /* last valid data position */
97 : size_t size; /* size of data segment */
98 : unsigned char data[]; /* data pointer */
99 : };
100 :
101 : /* First in first out queue structure. */
102 : struct stream_fifo {
103 : /* lock for mt-safe operations */
104 : pthread_mutex_t mtx;
105 :
106 : /* number of streams in this fifo */
107 : atomic_size_t count;
108 : #if defined DEV_BUILD
109 : atomic_size_t max_count;
110 : #endif
111 :
112 : struct stream *head;
113 : struct stream *tail;
114 : };
115 :
116 : /* Utility macros. */
117 : #define STREAM_SIZE(S) ((S)->size)
118 : /* number of bytes which can still be written */
119 : #define STREAM_WRITEABLE(S) ((S)->size - (S)->endp)
120 : /* number of bytes still to be read */
121 : #define STREAM_READABLE(S) ((S)->endp - (S)->getp)
122 :
123 : #define STREAM_CONCAT_REMAIN(S1, S2, size) ((size) - (S1)->endp - (S2)->endp)
124 :
125 : /* this macro is deprecated, but not slated for removal anytime soon */
126 : #define STREAM_DATA(S) ((S)->data)
127 :
128 : /* Stream prototypes.
129 : * For stream_{put,get}S, the S suffix mean:
130 : *
131 : * c: character (unsigned byte)
132 : * w: word (two bytes)
133 : * l: long (two words)
134 : * q: quad (four words)
135 : */
136 : extern struct stream *stream_new(size_t);
137 : extern void stream_free(struct stream *);
138 : /* Copy 'src' into 'dest', returns 'dest' */
139 : extern struct stream *stream_copy(struct stream *dest,
140 : const struct stream *src);
141 : extern struct stream *stream_dup(const struct stream *s);
142 :
143 : extern size_t stream_resize_inplace(struct stream **sptr, size_t newsize);
144 :
145 : extern size_t stream_get_getp(const struct stream *s);
146 : extern size_t stream_get_endp(const struct stream *s);
147 : extern size_t stream_get_size(const struct stream *s);
148 :
149 : /**
150 : * Create a new stream structure; copy offset bytes from s1 to the new
151 : * stream; copy s2 data to the new stream; copy rest of s1 data to the
152 : * new stream.
153 : */
154 : extern struct stream *stream_dupcat(const struct stream *s1,
155 : const struct stream *s2, size_t offset);
156 :
157 : extern void stream_set_getp(struct stream *, size_t);
158 : extern void stream_set_endp(struct stream *, size_t);
159 : extern void stream_forward_getp(struct stream *, size_t);
160 : extern bool stream_forward_getp2(struct stream *, size_t);
161 : extern void stream_rewind_getp(struct stream *s, size_t size);
162 : extern bool stream_rewind_getp2(struct stream *s, size_t size);
163 : extern void stream_forward_endp(struct stream *, size_t);
164 : extern bool stream_forward_endp2(struct stream *, size_t);
165 :
166 : /* steam_put: NULL source zeroes out size_t bytes of stream */
167 : extern void stream_put(struct stream *, const void *, size_t);
168 : extern int stream_putc(struct stream *, uint8_t);
169 : extern int stream_putc_at(struct stream *, size_t, uint8_t);
170 : extern int stream_putw(struct stream *, uint16_t);
171 : extern int stream_putw_at(struct stream *, size_t, uint16_t);
172 : extern int stream_put3(struct stream *, uint32_t);
173 : extern int stream_put3_at(struct stream *, size_t, uint32_t);
174 : extern int stream_putl(struct stream *, uint32_t);
175 : extern int stream_putl_at(struct stream *, size_t, uint32_t);
176 : extern int stream_putq(struct stream *, uint64_t);
177 : extern int stream_putq_at(struct stream *, size_t, uint64_t);
178 : extern int stream_put_ipv4(struct stream *, uint32_t);
179 : extern int stream_put_in_addr(struct stream *s, const struct in_addr *addr);
180 : extern bool stream_put_ipaddr(struct stream *s, struct ipaddr *ip);
181 : extern int stream_put_in_addr_at(struct stream *s, size_t putp,
182 : const struct in_addr *addr);
183 : extern int stream_put_in6_addr_at(struct stream *s, size_t putp,
184 : const struct in6_addr *addr);
185 : extern int stream_put_prefix_addpath(struct stream *s, const struct prefix *p,
186 : bool addpath_capable,
187 : uint32_t addpath_tx_id);
188 : extern int stream_put_prefix(struct stream *s, const struct prefix *p);
189 : extern int stream_put_labeled_prefix(struct stream *, const struct prefix *,
190 : mpls_label_t *, bool addpath_capable,
191 : uint32_t addpath_tx_id);
192 : extern void stream_get(void *, struct stream *, size_t);
193 : extern bool stream_get2(void *data, struct stream *s, size_t size);
194 : extern void stream_get_from(void *, struct stream *, size_t, size_t);
195 : extern uint8_t stream_getc(struct stream *);
196 : extern bool stream_getc2(struct stream *s, uint8_t *byte);
197 : extern uint8_t stream_getc_from(struct stream *, size_t);
198 : extern uint16_t stream_getw(struct stream *);
199 : extern bool stream_getw2(struct stream *s, uint16_t *word);
200 : extern uint16_t stream_getw_from(struct stream *, size_t);
201 : extern uint32_t stream_get3(struct stream *);
202 : extern uint32_t stream_get3_from(struct stream *, size_t);
203 : extern uint32_t stream_getl(struct stream *);
204 : extern bool stream_getl2(struct stream *s, uint32_t *l);
205 : extern uint32_t stream_getl_from(struct stream *, size_t);
206 : extern uint64_t stream_getq(struct stream *);
207 : extern uint64_t stream_getq_from(struct stream *, size_t);
208 : bool stream_getq2(struct stream *s, uint64_t *q);
209 : extern uint32_t stream_get_ipv4(struct stream *);
210 : extern bool stream_get_ipaddr(struct stream *s, struct ipaddr *ip);
211 :
212 : /* IEEE-754 floats */
213 : extern float stream_getf(struct stream *);
214 : extern double stream_getd(struct stream *);
215 : extern int stream_putf(struct stream *, float);
216 : extern int stream_putd(struct stream *, double);
217 :
218 : #undef stream_read
219 : #undef stream_write
220 :
221 : /* Deprecated: assumes blocking I/O. Will be removed.
222 : Use stream_read_try instead. */
223 : extern int stream_read(struct stream *, int, size_t);
224 :
225 : /* Read up to size bytes into the stream.
226 : Return code:
227 : >0: number of bytes read
228 : 0: end-of-file
229 : -1: fatal error
230 : -2: transient error, should retry later (i.e. EAGAIN or EINTR)
231 : This is suitable for use with non-blocking file descriptors.
232 : */
233 : extern ssize_t stream_read_try(struct stream *s, int fd, size_t size);
234 :
235 : extern ssize_t stream_recvmsg(struct stream *s, int fd, struct msghdr *,
236 : int flags, size_t size);
237 : extern ssize_t stream_recvfrom(struct stream *s, int fd, size_t len, int flags,
238 : struct sockaddr *from, socklen_t *fromlen);
239 : extern size_t stream_write(struct stream *, const void *, size_t);
240 :
241 : /* reset the stream. See Note above */
242 : extern void stream_reset(struct stream *);
243 : extern int stream_flush(struct stream *, int);
244 : extern int stream_empty(struct stream *); /* is the stream empty? */
245 :
246 : /* debugging */
247 : extern void stream_hexdump(const struct stream *s);
248 :
249 : /**
250 : * Reorganize the buffer data so it can fit more. This function is normally
251 : * called right after stream data is consumed so we can read more data
252 : * (the functions that consume data start with `stream_get*()` and macros
253 : * `STREAM_GET*()`).
254 : *
255 : * \param s stream pointer.
256 : */
257 : extern void stream_pulldown(struct stream *s);
258 :
259 : /* deprecated */
260 : extern uint8_t *stream_pnt(struct stream *);
261 :
262 : /*
263 : * Operations on struct stream_fifo.
264 : *
265 : * Each function has a safe variant, which ensures that the operation performed
266 : * is atomic with respect to the operations performed by all other safe
267 : * variants. In other words, the safe variants lock the stream_fifo's mutex
268 : * before performing their action. These are provided for convenience when
269 : * using stream_fifo in a multithreaded context, to alleviate the need for the
270 : * caller to implement their own synchronization around the stream_fifo.
271 : *
272 : * The following functions do not have safe variants. The caller must ensure
273 : * that these operations are performed safely in a multithreaded context:
274 : * - stream_fifo_new
275 : * - stream_fifo_free
276 : */
277 :
278 : /*
279 : * Create a new stream_fifo.
280 : *
281 : * Returns:
282 : * newly created stream_fifo
283 : */
284 : extern struct stream_fifo *stream_fifo_new(void);
285 :
286 : /*
287 : * Init or re-init an on-stack fifo. This allows use of a fifo struct without
288 : * requiring a malloc/free cycle.
289 : * Note well that the fifo must be de-inited with the 'fifo_deinit' api.
290 : */
291 : void stream_fifo_init(struct stream_fifo *fifo);
292 :
293 : /*
294 : * Deinit an on-stack fifo.
295 : */
296 : void stream_fifo_deinit(struct stream_fifo *fifo);
297 :
298 : /*
299 : * Push a stream onto a stream_fifo.
300 : *
301 : * fifo
302 : * the stream_fifo to push onto
303 : *
304 : * s
305 : * the stream to push onto the stream_fifo
306 : */
307 : extern void stream_fifo_push(struct stream_fifo *fifo, struct stream *s);
308 : extern void stream_fifo_push_safe(struct stream_fifo *fifo, struct stream *s);
309 :
310 : /*
311 : * Pop a stream off a stream_fifo.
312 : *
313 : * fifo
314 : * the stream_fifo to pop from
315 : *
316 : * Returns:
317 : * the next stream in the stream_fifo
318 : */
319 : extern struct stream *stream_fifo_pop(struct stream_fifo *fifo);
320 : extern struct stream *stream_fifo_pop_safe(struct stream_fifo *fifo);
321 :
322 : /*
323 : * Retrieve the next stream from a stream_fifo without popping it.
324 : *
325 : * fifo
326 : * the stream_fifo to operate on
327 : *
328 : * Returns:
329 : * the next stream that would be returned from stream_fifo_pop
330 : */
331 : extern struct stream *stream_fifo_head(struct stream_fifo *fifo);
332 : extern struct stream *stream_fifo_head_safe(struct stream_fifo *fifo);
333 :
334 : /*
335 : * Remove all streams from a stream_fifo.
336 : *
337 : * fifo
338 : * the stream_fifo to clean
339 : */
340 : extern void stream_fifo_clean(struct stream_fifo *fifo);
341 : extern void stream_fifo_clean_safe(struct stream_fifo *fifo);
342 :
343 : /*
344 : * Retrieve number of streams on a stream_fifo.
345 : *
346 : * fifo
347 : * the stream_fifo to retrieve the count for
348 : *
349 : * Returns:
350 : * the number of streams on the stream_fifo
351 : */
352 : extern size_t stream_fifo_count_safe(struct stream_fifo *fifo);
353 :
354 : /*
355 : * Free a stream_fifo.
356 : *
357 : * Calls stream_fifo_clean, then deinitializes the stream_fifo and frees it.
358 : *
359 : * fifo
360 : * the stream_fifo to free
361 : */
362 : extern void stream_fifo_free(struct stream_fifo *fifo);
363 :
364 : /* This is here because "<< 24" is particularly problematic in C.
365 : * This is because the left operand of << is integer-promoted, which means
366 : * an uint8_t gets converted into a *signed* int. Shifting into the sign
367 : * bit of a signed int is theoretically undefined behaviour, so - the left
368 : * operand needs to be cast to unsigned.
369 : *
370 : * This is not a problem for 16- or 8-bit values (they don't reach the sign
371 : * bit), for 64-bit values (you need to cast them anyway), and neither for
372 : * encoding (because it's downcasted.)
373 : */
374 0 : static inline const uint8_t *ptr_get_be64(const uint8_t *ptr, uint64_t *out)
375 : {
376 0 : uint32_t tmp1, tmp2;
377 :
378 0 : memcpy(&tmp1, ptr, sizeof(tmp1));
379 0 : memcpy(&tmp2, ptr + sizeof(tmp1), sizeof(tmp1));
380 :
381 0 : *out = (((uint64_t)ntohl(tmp1)) << 32) | ntohl(tmp2);
382 :
383 0 : return ptr + 8;
384 : }
385 :
386 0 : static inline const uint8_t *ptr_get_be32(const uint8_t *ptr, uint32_t *out)
387 : {
388 0 : uint32_t tmp;
389 :
390 0 : memcpy(&tmp, ptr, sizeof(tmp));
391 0 : *out = ntohl(tmp);
392 0 : return ptr + 4;
393 : }
394 :
395 0 : static inline uint8_t *ptr_get_be16(uint8_t *ptr, uint16_t *out)
396 : {
397 0 : uint16_t tmp;
398 :
399 0 : memcpy(&tmp, ptr, sizeof(tmp));
400 0 : *out = ntohs(tmp);
401 :
402 0 : return ptr + 2;
403 : }
404 :
405 : /*
406 : * so Normal stream_getX functions assert. Which is anathema
407 : * to keeping a daemon up and running when something goes south
408 : * Provide a stream_getX2 functions that do not assert.
409 : * In addition provide these macro's that upon failure
410 : * goto stream_failure. This is modeled upon some NL_XX
411 : * macros in the linux kernel.
412 : *
413 : * This change allows for proper memory freeing
414 : * after we've detected an error.
415 : *
416 : * In the future we will be removing the assert in
417 : * the stream functions but we need a transition
418 : * plan.
419 : */
420 : #define STREAM_GETC(S, P) \
421 : do { \
422 : uint8_t _pval; \
423 : if (!stream_getc2((S), &_pval)) \
424 : goto stream_failure; \
425 : (P) = _pval; \
426 : } while (0)
427 :
428 : #define STREAM_GETW(S, P) \
429 : do { \
430 : uint16_t _pval; \
431 : if (!stream_getw2((S), &_pval)) \
432 : goto stream_failure; \
433 : (P) = _pval; \
434 : } while (0)
435 :
436 : #define STREAM_GETL(S, P) \
437 : do { \
438 : uint32_t _pval; \
439 : if (!stream_getl2((S), &_pval)) \
440 : goto stream_failure; \
441 : (P) = _pval; \
442 : } while (0)
443 :
444 : #define STREAM_GETF(S, P) \
445 : do { \
446 : union { \
447 : float r; \
448 : uint32_t d; \
449 : } _pval; \
450 : if (!stream_getl2((S), &_pval.d)) \
451 : goto stream_failure; \
452 : (P) = _pval.r; \
453 : } while (0)
454 :
455 : #define STREAM_GETQ(S, P) \
456 : do { \
457 : uint64_t _pval; \
458 : if (!stream_getq2((S), &_pval)) \
459 : goto stream_failure; \
460 : (P) = _pval; \
461 : } while (0)
462 :
463 : #define STREAM_GET_IPADDR(S, P) \
464 : do { \
465 : if (!stream_get_ipaddr((S), (P))) \
466 : goto stream_failure; \
467 : } while (0)
468 :
469 : #define STREAM_GET(P, STR, SIZE) \
470 : do { \
471 : if (!stream_get2((P), (STR), (SIZE))) \
472 : goto stream_failure; \
473 : } while (0)
474 :
475 : #define STREAM_FORWARD_GETP(STR, SIZE) \
476 : do { \
477 : if (!stream_forward_getp2((STR), (SIZE))) \
478 : goto stream_failure; \
479 : } while (0)
480 :
481 : #define STREAM_REWIND_GETP(STR, SIZE) \
482 : do { \
483 : if (!stream_rewind_getp2((STR), (SIZE))) \
484 : goto stream_failure; \
485 : } while (0)
486 :
487 : #define STREAM_FORWARD_ENDP(STR, SIZE) \
488 : do { \
489 : if (!stream_forward_endp2((STR), (SIZE))) \
490 : goto stream_failure; \
491 : } while (0)
492 :
493 : #ifdef __cplusplus
494 : }
495 : #endif
496 :
497 : #endif /* _ZEBRA_STREAM_H */
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