1 /*
2 * include/proto/channel.h
3 * Channel management definitions, macros and inline functions.
4 *
5 * Copyright (C) 2000-2014 Willy Tarreau - w@1wt.eu
6 *
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation, version 2.1
10 * exclusively.
11 *
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with this library; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 #ifndef _PROTO_CHANNEL_H
23 #define _PROTO_CHANNEL_H
24
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <string.h>
28
29 #include <common/config.h>
30 #include <common/chunk.h>
31 #include <common/ticks.h>
32 #include <common/time.h>
33
34 #include <types/channel.h>
35 #include <types/global.h>
36 #include <types/stream.h>
37 #include <types/stream_interface.h>
38
39 #include <proto/applet.h>
40 #include <proto/task.h>
41
42 /* perform minimal intializations, report 0 in case of error, 1 if OK. */
43 int init_channel();
44
45 unsigned long long __channel_forward(struct channel *chn, unsigned long long bytes);
46
47 /* SI-to-channel functions working with buffers */
48 int bi_putblk(struct channel *chn, const char *str, int len);
49 struct buffer *bi_swpbuf(struct channel *chn, struct buffer *buf);
50 int bi_putchr(struct channel *chn, char c);
51 int bi_getline_nc(struct channel *chn, char **blk1, int *len1, char **blk2, int *len2);
52 int bi_getblk_nc(struct channel *chn, char **blk1, int *len1, char **blk2, int *len2);
53 int bo_inject(struct channel *chn, const char *msg, int len);
54 int bo_getline(struct channel *chn, char *str, int len);
55 int bo_getblk(struct channel *chn, char *blk, int len, int offset);
56 int bo_getline_nc(struct channel *chn, char **blk1, int *len1, char **blk2, int *len2);
57 int bo_getblk_nc(struct channel *chn, char **blk1, int *len1, char **blk2, int *len2);
58
59
60 /* returns a pointer to the stream the channel belongs to */
chn_strm(const struct channel * chn)61 static inline struct stream *chn_strm(const struct channel *chn)
62 {
63 if (chn->flags & CF_ISRESP)
64 return LIST_ELEM(chn, struct stream *, res);
65 else
66 return LIST_ELEM(chn, struct stream *, req);
67 }
68
69 /* returns a pointer to the stream interface feeding the channel (producer) */
chn_prod(const struct channel * chn)70 static inline struct stream_interface *chn_prod(const struct channel *chn)
71 {
72 if (chn->flags & CF_ISRESP)
73 return &LIST_ELEM(chn, struct stream *, res)->si[1];
74 else
75 return &LIST_ELEM(chn, struct stream *, req)->si[0];
76 }
77
78 /* returns a pointer to the stream interface consuming the channel (producer) */
chn_cons(const struct channel * chn)79 static inline struct stream_interface *chn_cons(const struct channel *chn)
80 {
81 if (chn->flags & CF_ISRESP)
82 return &LIST_ELEM(chn, struct stream *, res)->si[0];
83 else
84 return &LIST_ELEM(chn, struct stream *, req)->si[1];
85 }
86
87 /* Initialize all fields in the channel. */
channel_init(struct channel * chn)88 static inline void channel_init(struct channel *chn)
89 {
90 chn->buf = &buf_empty;
91 chn->to_forward = 0;
92 chn->last_read = now_ms;
93 chn->xfer_small = chn->xfer_large = 0;
94 chn->total = 0;
95 chn->pipe = NULL;
96 chn->analysers = 0;
97 chn->flags = 0;
98 }
99
100 /* Schedule up to <bytes> more bytes to be forwarded via the channel without
101 * notifying the owner task. Any data pending in the buffer are scheduled to be
102 * sent as well, in the limit of the number of bytes to forward. This must be
103 * the only method to use to schedule bytes to be forwarded. If the requested
104 * number is too large, it is automatically adjusted. The number of bytes taken
105 * into account is returned. Directly touching ->to_forward will cause lockups
106 * when buf->o goes down to zero if nobody is ready to push the remaining data.
107 */
channel_forward(struct channel * chn,unsigned long long bytes)108 static inline unsigned long long channel_forward(struct channel *chn, unsigned long long bytes)
109 {
110 /* hint: avoid comparisons on long long for the fast case, since if the
111 * length does not fit in an unsigned it, it will never be forwarded at
112 * once anyway.
113 */
114 if (bytes <= ~0U) {
115 unsigned int bytes32 = bytes;
116
117 if (bytes32 <= chn->buf->i) {
118 /* OK this amount of bytes might be forwarded at once */
119 b_adv(chn->buf, bytes32);
120 return bytes;
121 }
122 }
123 return __channel_forward(chn, bytes);
124 }
125
126 /* Forwards any input data and marks the channel for permanent forwarding */
channel_forward_forever(struct channel * chn)127 static inline void channel_forward_forever(struct channel *chn)
128 {
129 b_adv(chn->buf, chn->buf->i);
130 chn->to_forward = CHN_INFINITE_FORWARD;
131 }
132
133 /*********************************************************************/
134 /* These functions are used to compute various channel content sizes */
135 /*********************************************************************/
136
137 /* Reports non-zero if the channel is empty, which means both its
138 * buffer and pipe are empty. The construct looks strange but is
139 * jump-less and much more efficient on both 32 and 64-bit than
140 * the boolean test.
141 */
channel_is_empty(struct channel * c)142 static inline unsigned int channel_is_empty(struct channel *c)
143 {
144 return !(c->buf->o | (long)c->pipe);
145 }
146
147 /* Returns non-zero if the channel is rewritable, which means that the buffer
148 * it is attached to has at least <maxrewrite> bytes immediately available.
149 * This is used to decide when a request or response may be parsed when some
150 * data from a previous exchange might still be present.
151 */
channel_is_rewritable(const struct channel * chn)152 static inline int channel_is_rewritable(const struct channel *chn)
153 {
154 int rem = chn->buf->size;
155
156 rem -= chn->buf->o;
157 rem -= chn->buf->i;
158 rem -= global.tune.maxrewrite;
159 return rem >= 0;
160 }
161
162 /* Returns non-zero if the channel is congested with data in transit waiting
163 * for leaving, indicating to the caller that it should wait for the reserve to
164 * be released before starting to process new data in case it needs the ability
165 * to append data. This is meant to be used while waiting for a clean response
166 * buffer before processing a request.
167 */
channel_congested(const struct channel * chn)168 static inline int channel_congested(const struct channel *chn)
169 {
170 if (!chn->buf->o)
171 return 0;
172
173 if (!channel_is_rewritable(chn))
174 return 1;
175
176 if (chn->buf->p + chn->buf->i >
177 chn->buf->data + chn->buf->size - global.tune.maxrewrite)
178 return 1;
179
180 return 0;
181 }
182
183 /* Tells whether data are likely to leave the buffer. This is used to know when
184 * we can safely ignore the reserve since we know we cannot retry a connection.
185 * It returns zero if data are blocked, non-zero otherwise.
186 */
channel_may_send(const struct channel * chn)187 static inline int channel_may_send(const struct channel *chn)
188 {
189 return chn_cons(chn)->state == SI_ST_EST;
190 }
191
192 /* Returns non-zero if the channel can still receive data. This is used to
193 * decide when to stop reading into a buffer when we want to ensure that we
194 * leave the reserve untouched after all pending outgoing data are forwarded.
195 * The reserved space is taken into account if ->to_forward indicates that an
196 * end of transfer is close to happen. Note that both ->buf->o and ->to_forward
197 * are considered as available since they're supposed to leave the buffer. The
198 * test is optimized to avoid as many operations as possible for the fast case
199 * and to be used as an "if" condition. Just like channel_recv_limit(), we
200 * never allow to overwrite the reserve until the output stream interface is
201 * connected, otherwise we could spin on a POST with http-send-name-header.
202 */
channel_may_recv(const struct channel * chn)203 static inline int channel_may_recv(const struct channel *chn)
204 {
205 int rem = chn->buf->size;
206
207 if (chn->buf == &buf_empty)
208 return 1;
209
210 rem -= chn->buf->o;
211 rem -= chn->buf->i;
212 if (!rem)
213 return 0; /* buffer already full */
214
215 if (rem > global.tune.maxrewrite)
216 return 1; /* reserve not yet reached */
217
218 if (!channel_may_send(chn))
219 return 0; /* don't touch reserve until we can send */
220
221 /* Now we know there's some room left in the reserve and we may
222 * forward. As long as i-to_fwd < size-maxrw, we may still
223 * receive. This is equivalent to i+maxrw-size < to_fwd,
224 * which is logical since i+maxrw-size is what overlaps with
225 * the reserve, and we want to ensure they're covered by scheduled
226 * forwards.
227 */
228 rem = chn->buf->i + global.tune.maxrewrite - chn->buf->size;
229 return rem < 0 || (unsigned int)rem < chn->to_forward;
230 }
231
232 /* Returns true if the channel's input is already closed */
channel_input_closed(struct channel * chn)233 static inline int channel_input_closed(struct channel *chn)
234 {
235 return ((chn->flags & CF_SHUTR) != 0);
236 }
237
238 /* Returns true if the channel's output is already closed */
channel_output_closed(struct channel * chn)239 static inline int channel_output_closed(struct channel *chn)
240 {
241 return ((chn->flags & CF_SHUTW) != 0);
242 }
243
244 /* Check channel timeouts, and set the corresponding flags. The likely/unlikely
245 * have been optimized for fastest normal path. The read/write timeouts are not
246 * set if there was activity on the channel. That way, we don't have to update
247 * the timeout on every I/O. Note that the analyser timeout is always checked.
248 */
channel_check_timeouts(struct channel * chn)249 static inline void channel_check_timeouts(struct channel *chn)
250 {
251 if (likely(!(chn->flags & (CF_SHUTR|CF_READ_TIMEOUT|CF_READ_ACTIVITY|CF_READ_NOEXP))) &&
252 unlikely(tick_is_expired(chn->rex, now_ms)))
253 chn->flags |= CF_READ_TIMEOUT;
254
255 if (likely(!(chn->flags & (CF_SHUTW|CF_WRITE_TIMEOUT|CF_WRITE_ACTIVITY|CF_WRITE_EVENT))) &&
256 unlikely(tick_is_expired(chn->wex, now_ms)))
257 chn->flags |= CF_WRITE_TIMEOUT;
258
259 if (likely(!(chn->flags & CF_ANA_TIMEOUT)) &&
260 unlikely(tick_is_expired(chn->analyse_exp, now_ms)))
261 chn->flags |= CF_ANA_TIMEOUT;
262 }
263
264 /* Erase any content from channel <buf> and adjusts flags accordingly. Note
265 * that any spliced data is not affected since we may not have any access to
266 * it.
267 */
channel_erase(struct channel * chn)268 static inline void channel_erase(struct channel *chn)
269 {
270 chn->to_forward = 0;
271 b_reset(chn->buf);
272 }
273
274 /* marks the channel as "shutdown" ASAP for reads */
channel_shutr_now(struct channel * chn)275 static inline void channel_shutr_now(struct channel *chn)
276 {
277 chn->flags |= CF_SHUTR_NOW;
278 }
279
280 /* marks the channel as "shutdown" ASAP for writes */
channel_shutw_now(struct channel * chn)281 static inline void channel_shutw_now(struct channel *chn)
282 {
283 chn->flags |= CF_SHUTW_NOW;
284 }
285
286 /* marks the channel as "shutdown" ASAP in both directions */
channel_abort(struct channel * chn)287 static inline void channel_abort(struct channel *chn)
288 {
289 chn->flags |= CF_SHUTR_NOW | CF_SHUTW_NOW;
290 chn->flags &= ~CF_AUTO_CONNECT;
291 }
292
293 /* allow the consumer to try to establish a new connection. */
channel_auto_connect(struct channel * chn)294 static inline void channel_auto_connect(struct channel *chn)
295 {
296 chn->flags |= CF_AUTO_CONNECT;
297 }
298
299 /* prevent the consumer from trying to establish a new connection, and also
300 * disable auto shutdown forwarding.
301 */
channel_dont_connect(struct channel * chn)302 static inline void channel_dont_connect(struct channel *chn)
303 {
304 chn->flags &= ~(CF_AUTO_CONNECT|CF_AUTO_CLOSE);
305 }
306
307 /* allow the producer to forward shutdown requests */
channel_auto_close(struct channel * chn)308 static inline void channel_auto_close(struct channel *chn)
309 {
310 chn->flags |= CF_AUTO_CLOSE;
311 }
312
313 /* prevent the producer from forwarding shutdown requests */
channel_dont_close(struct channel * chn)314 static inline void channel_dont_close(struct channel *chn)
315 {
316 chn->flags &= ~CF_AUTO_CLOSE;
317 }
318
319 /* allow the producer to read / poll the input */
channel_auto_read(struct channel * chn)320 static inline void channel_auto_read(struct channel *chn)
321 {
322 chn->flags &= ~CF_DONT_READ;
323 }
324
325 /* prevent the producer from read / poll the input */
channel_dont_read(struct channel * chn)326 static inline void channel_dont_read(struct channel *chn)
327 {
328 chn->flags |= CF_DONT_READ;
329 }
330
331
332 /*************************************************/
333 /* Buffer operations in the context of a channel */
334 /*************************************************/
335
336
337 /* Return the max number of bytes the buffer can contain so that once all the
338 * pending bytes are forwarded, the buffer still has global.tune.maxrewrite
339 * bytes free. The result sits between chn->size - maxrewrite and chn->size.
340 * It is important to mention that if buf->i is already larger than size-maxrw
341 * the condition above cannot be satisfied and the lowest size will be returned
342 * anyway. The principles are the following :
343 * 0) the empty buffer has a limit of zero
344 * 1) a non-connected buffer cannot touch the reserve
345 * 2) infinite forward can always fill the buffer since all data will leave
346 * 3) all output bytes are considered in transit since they're leaving
347 * 4) all input bytes covered by to_forward are considered in transit since
348 * they'll be converted to output bytes.
349 * 5) all input bytes not covered by to_forward as considered remaining
350 * 6) all bytes scheduled to be forwarded minus what is already in the input
351 * buffer will be in transit during future rounds.
352 * 7) 4+5+6 imply that the amount of input bytes (i) is irrelevant to the max
353 * usable length, only to_forward and output count. The difference is
354 * visible when to_forward > i.
355 * 8) the reserve may be covered up to the amount of bytes in transit since
356 * these bytes will only take temporary space.
357 *
358 * A typical buffer looks like this :
359 *
360 * <-------------- max_len ----------->
361 * <---- o ----><----- i -----> <--- 0..maxrewrite --->
362 * +------------+--------------+-------+----------------------+
363 * |////////////|\\\\\\\\\\\\\\|xxxxxxx| reserve |
364 * +------------+--------+-----+-------+----------------------+
365 * <- fwd -> <-avail->
366 *
367 * Or when to_forward > i :
368 *
369 * <-------------- max_len ----------->
370 * <---- o ----><----- i -----> <--- 0..maxrewrite --->
371 * +------------+--------------+-------+----------------------+
372 * |////////////|\\\\\\\\\\\\\\|xxxxxxx| reserve |
373 * +------------+--------+-----+-------+----------------------+
374 * <-avail->
375 * <------------------ fwd ---------------->
376 *
377 * - the amount of buffer bytes in transit is : min(i, fwd) + o
378 * - some scheduled bytes may be in transit (up to fwd - i)
379 * - the reserve is max(0, maxrewrite - transit)
380 * - the maximum usable buffer length is size - reserve.
381 * - the available space is max_len - i - o
382 *
383 * So the formula to compute the buffer's maximum length to protect the reserve
384 * when reading new data is :
385 *
386 * max = size - maxrewrite + min(maxrewrite, transit)
387 * = size - max(maxrewrite - transit, 0)
388 *
389 * But WARNING! The conditions might change during the transfer and it could
390 * very well happen that a buffer would contain more bytes than max_len due to
391 * i+o already walking over the reserve (eg: after a header rewrite), including
392 * i or o alone hitting the limit. So it is critical to always consider that
393 * bounds may have already been crossed and that available space may be negative
394 * for example. Due to this it is perfectly possible for this function to return
395 * a value that is lower than current i+o.
396 */
channel_recv_limit(const struct channel * chn)397 static inline int channel_recv_limit(const struct channel *chn)
398 {
399 unsigned int transit;
400 int reserve;
401
402 /* return zero if empty */
403 reserve = chn->buf->size;
404 if (chn->buf == &buf_empty)
405 goto end;
406
407 /* return size - maxrewrite if we can't send */
408 reserve = global.tune.maxrewrite;
409 if (unlikely(!channel_may_send(chn)))
410 goto end;
411
412 /* We need to check what remains of the reserve after o and to_forward
413 * have been transmitted, but they can overflow together and they can
414 * cause an integer underflow in the comparison since both are unsigned
415 * while maxrewrite is signed.
416 * The code below has been verified for being a valid check for this :
417 * - if (o + to_forward) overflow => return size [ large enough ]
418 * - if o + to_forward >= maxrw => return size [ large enough ]
419 * - otherwise return size - (maxrw - (o + to_forward))
420 */
421 transit = chn->buf->o + chn->to_forward;
422 reserve -= transit;
423 if (transit < chn->to_forward || // addition overflow
424 transit >= (unsigned)global.tune.maxrewrite) // enough transit data
425 return chn->buf->size;
426 end:
427 return chn->buf->size - reserve;
428 }
429
430 /* Returns the amount of space available at the input of the buffer, taking the
431 * reserved space into account if ->to_forward indicates that an end of transfer
432 * is close to happen. The test is optimized to avoid as many operations as
433 * possible for the fast case.
434 */
channel_recv_max(const struct channel * chn)435 static inline int channel_recv_max(const struct channel *chn)
436 {
437 int ret;
438
439 ret = channel_recv_limit(chn) - chn->buf->i - chn->buf->o;
440 if (ret < 0)
441 ret = 0;
442 return ret;
443 }
444
445 /* Allocates a buffer for channel <chn>, but only if it's guaranteed that it's
446 * not the last available buffer or it's the response buffer. Unless the buffer
447 * is the response buffer, an extra control is made so that we always keep
448 * <tune.buffers.reserved> buffers available after this allocation. Returns 0 in
449 * case of failure, non-zero otherwise.
450 *
451 * If no buffer are available, the requester, represented by <wait> pointer,
452 * will be added in the list of objects waiting for an available buffer.
453 */
channel_alloc_buffer(struct channel * chn,struct buffer_wait * wait)454 static inline int channel_alloc_buffer(struct channel *chn, struct buffer_wait *wait)
455 {
456 int margin = 0;
457
458 if (!(chn->flags & CF_ISRESP))
459 margin = global.tune.reserved_bufs;
460
461 if (b_alloc_margin(&chn->buf, margin) != NULL)
462 return 1;
463
464 if (LIST_ISEMPTY(&wait->list))
465 LIST_ADDQ(&buffer_wq, &wait->list);
466 return 0;
467 }
468
469 /* Releases a possibly allocated buffer for channel <chn>. If it was not
470 * allocated, this function does nothing. Else the buffer is released and we try
471 * to wake up as many streams/applets as possible. */
channel_release_buffer(struct channel * chn,struct buffer_wait * wait)472 static inline void channel_release_buffer(struct channel *chn, struct buffer_wait *wait)
473 {
474 if (chn->buf->size && buffer_empty(chn->buf)) {
475 b_free(&chn->buf);
476 offer_buffers(wait->target, tasks_run_queue + applets_active_queue);
477 }
478 }
479
480 /* Truncate any unread data in the channel's buffer, and disable forwarding.
481 * Outgoing data are left intact. This is mainly to be used to send error
482 * messages after existing data.
483 */
channel_truncate(struct channel * chn)484 static inline void channel_truncate(struct channel *chn)
485 {
486 if (!chn->buf->o)
487 return channel_erase(chn);
488
489 chn->to_forward = 0;
490 if (!chn->buf->i)
491 return;
492
493 chn->buf->i = 0;
494 }
495
496 /*
497 * Advance the channel buffer's read pointer by <len> bytes. This is useful
498 * when data have been read directly from the buffer. It is illegal to call
499 * this function with <len> causing a wrapping at the end of the buffer. It's
500 * the caller's responsibility to ensure that <len> is never larger than
501 * chn->o. Channel flag WRITE_PARTIAL is set.
502 */
bo_skip(struct channel * chn,int len)503 static inline void bo_skip(struct channel *chn, int len)
504 {
505 chn->buf->o -= len;
506
507 if (buffer_empty(chn->buf))
508 chn->buf->p = chn->buf->data;
509
510 /* notify that some data was written to the SI from the buffer */
511 chn->flags |= CF_WRITE_PARTIAL | CF_WRITE_EVENT;
512 }
513
514 /* Tries to copy chunk <chunk> into the channel's buffer after length controls.
515 * The chn->o and to_forward pointers are updated. If the channel's input is
516 * closed, -2 is returned. If the block is too large for this buffer, -3 is
517 * returned. If there is not enough room left in the buffer, -1 is returned.
518 * Otherwise the number of bytes copied is returned (0 being a valid number).
519 * Channel flag READ_PARTIAL is updated if some data can be transferred. The
520 * chunk's length is updated with the number of bytes sent.
521 */
bi_putchk(struct channel * chn,struct chunk * chunk)522 static inline int bi_putchk(struct channel *chn, struct chunk *chunk)
523 {
524 int ret;
525
526 ret = bi_putblk(chn, chunk->str, chunk->len);
527 if (ret > 0)
528 chunk->len -= ret;
529 return ret;
530 }
531
532 /* Tries to copy string <str> at once into the channel's buffer after length
533 * controls. The chn->o and to_forward pointers are updated. If the channel's
534 * input is closed, -2 is returned. If the block is too large for this buffer,
535 * -3 is returned. If there is not enough room left in the buffer, -1 is
536 * returned. Otherwise the number of bytes copied is returned (0 being a valid
537 * number). Channel flag READ_PARTIAL is updated if some data can be
538 * transferred.
539 */
bi_putstr(struct channel * chn,const char * str)540 static inline int bi_putstr(struct channel *chn, const char *str)
541 {
542 return bi_putblk(chn, str, strlen(str));
543 }
544
545 /*
546 * Return one char from the channel's buffer. If the buffer is empty and the
547 * channel is closed, return -2. If the buffer is just empty, return -1. The
548 * buffer's pointer is not advanced, it's up to the caller to call bo_skip(buf,
549 * 1) when it has consumed the char. Also note that this function respects the
550 * chn->o limit.
551 */
bo_getchr(struct channel * chn)552 static inline int bo_getchr(struct channel *chn)
553 {
554 /* closed or empty + imminent close = -2; empty = -1 */
555 if (unlikely((chn->flags & CF_SHUTW) || channel_is_empty(chn))) {
556 if (chn->flags & (CF_SHUTW|CF_SHUTW_NOW))
557 return -2;
558 return -1;
559 }
560 return *buffer_wrap_sub(chn->buf, chn->buf->p - chn->buf->o);
561 }
562
563
564 #endif /* _PROTO_CHANNEL_H */
565
566 /*
567 * Local variables:
568 * c-indent-level: 8
569 * c-basic-offset: 8
570 * End:
571 */
572