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3 * Copyright (C) 1999 Kunihiro Ishiguro
5 * This file is part of GNU Zebra.
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
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.
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
22 #ifndef _ZEBRA_STREAM_H
23 #define _ZEBRA_STREAM_H
27 #include "frratomic.h"
32 * A stream is an arbitrary buffer, whose contents generally are assumed to
33 * be in network order.
35 * A stream has the following attributes associated with it:
37 * - size: the allocated, invariant size of the buffer.
39 * - getp: the get position marker, denoting the offset in the stream where
40 * the next read (or 'get') will be from. This getp marker is
41 * automatically adjusted when data is read from the stream, the
42 * user may also manipulate this offset as they wish, within limits
45 * - endp: the end position marker, denoting the offset in the stream where
46 * valid data ends, and if the user attempted to write (or
47 * 'put') data where that data would be written (or 'put') to.
49 * These attributes are all size_t values.
53 * 1. getp can never exceed endp
55 * - hence if getp is equal to endp, there is no more valid data that can be
56 * gotten from the stream (though, the user may reposition getp to earlier in
57 * the stream, if they wish).
59 * 2. endp can never exceed size
61 * - hence, if endp is equal to size, then the stream is full, and no more
62 * data can be written to the stream.
64 * In other words the following must always be true, and the stream
65 * abstraction is allowed internally to assert that the following property
66 * holds true for a stream, as and when it wishes:
68 * getp <= endp <= size
70 * It is the users responsibility to ensure this property is never violated.
72 * A stream therefore can be thought of like this:
74 * ---------------------------------------------------
75 * |XXXXXXXXXXXXXXXXXXXXXXXX |
76 * ---------------------------------------------------
80 * This shows a stream containing data (shown as 'X') up to the endp offset.
81 * The stream is empty from endp to size. Without adjusting getp, there are
82 * still endp-getp bytes of valid data to be read from the stream.
84 * Methods are provided to get and put to/from the stream, as well as
85 * retrieve the values of the 3 markers and manipulate the getp marker.
88 * At the moment, newly allocated streams are zero filled. Hence, one can
89 * use stream_forward_endp() to effectively create arbitrary zero-fill
90 * padding. However, note that stream_reset() does *not* zero-out the
91 * stream. This property should **not** be relied upon.
93 * Best practice is to use stream_put (<stream *>, NULL, <size>) to zero out
94 * any part of a stream which isn't otherwise written to.
101 /* Remainder is ***private*** to stream
102 * direct access is frowned upon!
103 * Use the appropriate functions/macros
105 size_t getp
; /* next get position */
106 size_t endp
; /* last valid data position */
107 size_t size
; /* size of data segment */
108 unsigned char *data
; /* data pointer */
111 /* First in first out queue structure. */
113 /* lock for mt-safe operations */
116 /* number of streams in this fifo */
117 _Atomic
size_t count
;
118 #if defined DEV_BUILD
119 _Atomic
size_t max_count
;
126 /* Utility macros. */
127 #define STREAM_SIZE(S) ((S)->size)
128 /* number of bytes which can still be written */
129 #define STREAM_WRITEABLE(S) ((S)->size - (S)->endp)
130 /* number of bytes still to be read */
131 #define STREAM_READABLE(S) ((S)->endp - (S)->getp)
133 #define STREAM_CONCAT_REMAIN(S1, S2, size) ((size) - (S1)->endp - (S2)->endp)
135 /* deprecated macros - do not use in new code */
136 #if defined(VERSION_TYPE_DEV) && CONFDATE > 20181128
137 CPP_NOTICE("lib: time to remove deprecated stream.h macros")
139 #define STREAM_PNT(S) stream_pnt((S))
140 #define STREAM_REMAIN(S) STREAM_WRITEABLE((S))
142 /* this macro is deprecated, but not slated for removal anytime soon */
143 #define STREAM_DATA(S) ((S)->data)
145 /* Stream prototypes.
146 * For stream_{put,get}S, the S suffix mean:
148 * c: character (unsigned byte)
149 * w: word (two bytes)
150 * l: long (two words)
151 * q: quad (four words)
153 extern struct stream
*stream_new(size_t);
154 extern void stream_free(struct stream
*);
155 extern struct stream
*stream_copy(struct stream
*, struct stream
*src
);
156 extern struct stream
*stream_dup(struct stream
*);
157 extern size_t stream_resize(struct stream
*, size_t);
158 extern size_t stream_get_getp(struct stream
*);
159 extern size_t stream_get_endp(struct stream
*);
160 extern size_t stream_get_size(struct stream
*);
161 extern uint8_t *stream_get_data(struct stream
*);
164 * Create a new stream structure; copy offset bytes from s1 to the new
165 * stream; copy s2 data to the new stream; copy rest of s1 data to the
168 extern struct stream
*stream_dupcat(struct stream
*s1
, struct stream
*s2
,
171 extern void stream_set_getp(struct stream
*, size_t);
172 extern void stream_set_endp(struct stream
*, size_t);
173 extern void stream_forward_getp(struct stream
*, size_t);
174 extern void stream_forward_endp(struct stream
*, size_t);
176 /* steam_put: NULL source zeroes out size_t bytes of stream */
177 extern void stream_put(struct stream
*, const void *, size_t);
178 extern int stream_putc(struct stream
*, uint8_t);
179 extern int stream_putc_at(struct stream
*, size_t, uint8_t);
180 extern int stream_putw(struct stream
*, uint16_t);
181 extern int stream_putw_at(struct stream
*, size_t, uint16_t);
182 extern int stream_put3(struct stream
*, uint32_t);
183 extern int stream_put3_at(struct stream
*, size_t, uint32_t);
184 extern int stream_putl(struct stream
*, uint32_t);
185 extern int stream_putl_at(struct stream
*, size_t, uint32_t);
186 extern int stream_putq(struct stream
*, uint64_t);
187 extern int stream_putq_at(struct stream
*, size_t, uint64_t);
188 extern int stream_put_ipv4(struct stream
*, uint32_t);
189 extern int stream_put_in_addr(struct stream
*, struct in_addr
*);
190 extern int stream_put_in_addr_at(struct stream
*, size_t, struct in_addr
*);
191 extern int stream_put_in6_addr_at(struct stream
*, size_t, struct in6_addr
*);
192 extern int stream_put_prefix_addpath(struct stream
*, struct prefix
*,
194 uint32_t addpath_tx_id
);
195 extern int stream_put_prefix(struct stream
*, struct prefix
*);
196 extern int stream_put_labeled_prefix(struct stream
*, struct prefix
*,
198 extern void stream_get(void *, struct stream
*, size_t);
199 extern bool stream_get2(void *data
, struct stream
*s
, size_t size
);
200 extern void stream_get_from(void *, struct stream
*, size_t, size_t);
201 extern uint8_t stream_getc(struct stream
*);
202 extern bool stream_getc2(struct stream
*s
, uint8_t *byte
);
203 extern uint8_t stream_getc_from(struct stream
*, size_t);
204 extern uint16_t stream_getw(struct stream
*);
205 extern bool stream_getw2(struct stream
*s
, uint16_t *word
);
206 extern uint16_t stream_getw_from(struct stream
*, size_t);
207 extern uint32_t stream_get3(struct stream
*);
208 extern uint32_t stream_get3_from(struct stream
*, size_t);
209 extern uint32_t stream_getl(struct stream
*);
210 extern bool stream_getl2(struct stream
*s
, uint32_t *l
);
211 extern uint32_t stream_getl_from(struct stream
*, size_t);
212 extern uint64_t stream_getq(struct stream
*);
213 extern uint64_t stream_getq_from(struct stream
*, size_t);
214 extern uint32_t stream_get_ipv4(struct stream
*);
216 /* IEEE-754 floats */
217 extern float stream_getf(struct stream
*);
218 extern double stream_getd(struct stream
*);
219 extern int stream_putf(struct stream
*, float);
220 extern int stream_putd(struct stream
*, double);
225 /* Deprecated: assumes blocking I/O. Will be removed.
226 Use stream_read_try instead. */
227 extern int stream_read(struct stream
*, int, size_t);
229 /* Read up to size bytes into the stream.
231 >0: number of bytes read
234 -2: transient error, should retry later (i.e. EAGAIN or EINTR)
235 This is suitable for use with non-blocking file descriptors.
237 extern ssize_t
stream_read_try(struct stream
*s
, int fd
, size_t size
);
239 extern ssize_t
stream_recvmsg(struct stream
*s
, int fd
, struct msghdr
*,
240 int flags
, size_t size
);
241 extern ssize_t
stream_recvfrom(struct stream
*s
, int fd
, size_t len
, int flags
,
242 struct sockaddr
*from
, socklen_t
*fromlen
);
243 extern size_t stream_write(struct stream
*, const void *, size_t);
245 /* reset the stream. See Note above */
246 extern void stream_reset(struct stream
*);
247 extern int stream_flush(struct stream
*, int);
248 extern int stream_empty(struct stream
*); /* is the stream empty? */
251 extern uint8_t *stream_pnt(struct stream
*);
254 * Operations on struct stream_fifo.
256 * Each function has a safe variant, which ensures that the operation performed
257 * is atomic with respect to the operations performed by all other safe
258 * variants. In other words, the safe variants lock the stream_fifo's mutex
259 * before performing their action. These are provided for convenience when
260 * using stream_fifo in a multithreaded context, to alleviate the need for the
261 * caller to implement their own synchronization around the stream_fifo.
263 * The following functions do not have safe variants. The caller must ensure
264 * that these operations are performed safely in a multithreaded context:
270 * Create a new stream_fifo.
273 * newly created stream_fifo
275 extern struct stream_fifo
*stream_fifo_new(void);
278 * Push a stream onto a stream_fifo.
281 * the stream_fifo to push onto
284 * the stream to push onto the stream_fifo
286 extern void stream_fifo_push(struct stream_fifo
*fifo
, struct stream
*s
);
287 extern void stream_fifo_push_safe(struct stream_fifo
*fifo
, struct stream
*s
);
290 * Pop a stream off a stream_fifo.
293 * the stream_fifo to pop from
296 * the next stream in the stream_fifo
298 extern struct stream
*stream_fifo_pop(struct stream_fifo
*fifo
);
299 extern struct stream
*stream_fifo_pop_safe(struct stream_fifo
*fifo
);
302 * Retrieve the next stream from a stream_fifo without popping it.
305 * the stream_fifo to operate on
308 * the next stream that would be returned from stream_fifo_pop
310 extern struct stream
*stream_fifo_head(struct stream_fifo
*fifo
);
311 extern struct stream
*stream_fifo_head_safe(struct stream_fifo
*fifo
);
314 * Remove all streams from a stream_fifo.
317 * the stream_fifo to clean
319 extern void stream_fifo_clean(struct stream_fifo
*fifo
);
320 extern void stream_fifo_clean_safe(struct stream_fifo
*fifo
);
323 * Retrieve number of streams on a stream_fifo.
326 * the stream_fifo to retrieve the count for
329 * the number of streams on the stream_fifo
331 extern size_t stream_fifo_count_safe(struct stream_fifo
*fifo
);
334 * Free a stream_fifo.
336 * Calls stream_fifo_clean, then deinitializes the stream_fifo and frees it.
339 * the stream_fifo to free
341 extern void stream_fifo_free(struct stream_fifo
*fifo
);
343 /* This is here because "<< 24" is particularly problematic in C.
344 * This is because the left operand of << is integer-promoted, which means
345 * an uint8_t gets converted into a *signed* int. Shifting into the sign
346 * bit of a signed int is theoretically undefined behaviour, so - the left
347 * operand needs to be cast to unsigned.
349 * This is not a problem for 16- or 8-bit values (they don't reach the sign
350 * bit), for 64-bit values (you need to cast them anyway), and neither for
351 * encoding (because it's downcasted.)
353 static inline uint8_t *ptr_get_be32(uint8_t *ptr
, uint32_t *out
)
356 memcpy(&tmp
, ptr
, sizeof(tmp
));
362 * so Normal stream_getX functions assert. Which is anathema
363 * to keeping a daemon up and running when something goes south
364 * Provide a stream_getX2 functions that do not assert.
365 * In addition provide these macro's that upon failure
366 * goto stream_failure. This is modeled upon some NL_XX
367 * macros in the linux kernel.
369 * This change allows for proper memory freeing
370 * after we've detected an error.
372 * In the future we will be removing the assert in
373 * the stream functions but we need a transition
376 #define STREAM_GETC(S, P) \
379 if (!stream_getc2((S), &_pval)) \
380 goto stream_failure; \
384 #define STREAM_GETW(S, P) \
387 if (!stream_getw2((S), &_pval)) \
388 goto stream_failure; \
392 #define STREAM_GETL(S, P) \
395 if (!stream_getl2((S), &_pval)) \
396 goto stream_failure; \
400 #define STREAM_GET(P, STR, SIZE) \
402 if (!stream_get2((P), (STR), (SIZE))) \
403 goto stream_failure; \
406 #endif /* _ZEBRA_STREAM_H */