1 /*
2 * Copyright (c) 2008-2012 Niels Provos and Nick Mathewson
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * 3. The name of the author may not be used to endorse or promote products
13 * derived from this software without specific prior written permission.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26 #ifndef BUFFEREVENT_INTERNAL_H_INCLUDED_
27 #define BUFFEREVENT_INTERNAL_H_INCLUDED_
28
29 #ifdef __cplusplus
30 extern "C" {
31 #endif
32
33 #include "event2/event-config.h"
34 #include "event2/event_struct.h"
35 #include "evconfig-private.h"
36 #include "event2/util.h"
37 #include "defer-internal.h"
38 #include "evthread-internal.h"
39 #include "event2/thread.h"
40 #include "ratelim-internal.h"
41 #include "event2/bufferevent_struct.h"
42
43 #include "ipv6-internal.h"
44 #ifdef _WIN32
45 #include <ws2tcpip.h>
46 #endif
47 #ifdef EVENT__HAVE_NETINET_IN_H
48 #include <netinet/in.h>
49 #endif
50 #ifdef EVENT__HAVE_NETINET_IN6_H
51 #include <netinet/in6.h>
52 #endif
53
54 /* These flags are reasons that we might be declining to actually enable
55 reading or writing on a bufferevent.
56 */
57
58 /* On a all bufferevents, for reading: used when we have read up to the
59 watermark value.
60
61 On a filtering bufferevent, for writing: used when the underlying
62 bufferevent's write buffer has been filled up to its watermark
63 value.
64 */
65 #define BEV_SUSPEND_WM 0x01
66 /* On a base bufferevent: when we have emptied a bandwidth buckets */
67 #define BEV_SUSPEND_BW 0x02
68 /* On a base bufferevent: when we have emptied the group's bandwidth bucket. */
69 #define BEV_SUSPEND_BW_GROUP 0x04
70 /* On a socket bufferevent: can't do any operations while we're waiting for
71 * name lookup to finish. */
72 #define BEV_SUSPEND_LOOKUP 0x08
73 /* On a base bufferevent, for reading: used when a filter has choked this
74 * (underlying) bufferevent because it has stopped reading from it. */
75 #define BEV_SUSPEND_FILT_READ 0x10
76
77 typedef ev_uint16_t bufferevent_suspend_flags;
78
79 struct bufferevent_rate_limit_group {
80 /** List of all members in the group */
81 LIST_HEAD(rlim_group_member_list, bufferevent_private) members;
82 /** Current limits for the group. */
83 struct ev_token_bucket rate_limit;
84 struct ev_token_bucket_cfg rate_limit_cfg;
85
86 /** True iff we don't want to read from any member of the group.until
87 * the token bucket refills. */
88 unsigned read_suspended : 1;
89 /** True iff we don't want to write from any member of the group.until
90 * the token bucket refills. */
91 unsigned write_suspended : 1;
92 /** True iff we were unable to suspend one of the bufferevents in the
93 * group for reading the last time we tried, and we should try
94 * again. */
95 unsigned pending_unsuspend_read : 1;
96 /** True iff we were unable to suspend one of the bufferevents in the
97 * group for writing the last time we tried, and we should try
98 * again. */
99 unsigned pending_unsuspend_write : 1;
100
101 /*@{*/
102 /** Total number of bytes read or written in this group since last
103 * reset. */
104 ev_uint64_t total_read;
105 ev_uint64_t total_written;
106 /*@}*/
107
108 /** The number of bufferevents in the group. */
109 int n_members;
110
111 /** The smallest number of bytes that any member of the group should
112 * be limited to read or write at a time. */
113 ev_ssize_t min_share;
114 ev_ssize_t configured_min_share;
115
116 /** Timeout event that goes off once a tick, when the bucket is ready
117 * to refill. */
118 struct event master_refill_event;
119
120 /** Seed for weak random number generator. Protected by 'lock' */
121 struct evutil_weakrand_state weakrand_seed;
122
123 /** Lock to protect the members of this group. This lock should nest
124 * within every bufferevent lock: if you are holding this lock, do
125 * not assume you can lock another bufferevent. */
126 void *lock;
127 };
128
129 /** Fields for rate-limiting a single bufferevent. */
130 struct bufferevent_rate_limit {
131 /* Linked-list elements for storing this bufferevent_private in a
132 * group.
133 *
134 * Note that this field is supposed to be protected by the group
135 * lock */
136 LIST_ENTRY(bufferevent_private) next_in_group;
137 /** The rate-limiting group for this bufferevent, or NULL if it is
138 * only rate-limited on its own. */
139 struct bufferevent_rate_limit_group *group;
140
141 /* This bufferevent's current limits. */
142 struct ev_token_bucket limit;
143 /* Pointer to the rate-limit configuration for this bufferevent.
144 * Can be shared. XXX reference-count this? */
145 struct ev_token_bucket_cfg *cfg;
146
147 /* Timeout event used when one this bufferevent's buckets are
148 * empty. */
149 struct event refill_bucket_event;
150 };
151
152 /** Parts of the bufferevent structure that are shared among all bufferevent
153 * types, but not exposed in bufferevent_struct.h. */
154 struct bufferevent_private {
155 /** The underlying bufferevent structure. */
156 struct bufferevent bev;
157
158 /** Evbuffer callback to enforce watermarks on input. */
159 struct evbuffer_cb_entry *read_watermarks_cb;
160
161 /** If set, we should free the lock when we free the bufferevent. */
162 unsigned own_lock : 1;
163
164 /** Flag: set if we have deferred callbacks and a read callback is
165 * pending. */
166 unsigned readcb_pending : 1;
167 /** Flag: set if we have deferred callbacks and a write callback is
168 * pending. */
169 unsigned writecb_pending : 1;
170 /** Flag: set if we are currently busy connecting. */
171 unsigned connecting : 1;
172 /** Flag: set if a connect failed prematurely; this is a hack for
173 * getting around the bufferevent abstraction. */
174 unsigned connection_refused : 1;
175 /** Set to the events pending if we have deferred callbacks and
176 * an events callback is pending. */
177 short eventcb_pending;
178
179 /** If set, read is suspended until one or more conditions are over.
180 * The actual value here is a bitfield of those conditions; see the
181 * BEV_SUSPEND_* flags above. */
182 bufferevent_suspend_flags read_suspended;
183
184 /** If set, writing is suspended until one or more conditions are over.
185 * The actual value here is a bitfield of those conditions; see the
186 * BEV_SUSPEND_* flags above. */
187 bufferevent_suspend_flags write_suspended;
188
189 /** Set to the current socket errno if we have deferred callbacks and
190 * an events callback is pending. */
191 int errno_pending;
192
193 /** The DNS error code for bufferevent_socket_connect_hostname */
194 int dns_error;
195
196 /** Used to implement deferred callbacks */
197 struct event_callback deferred;
198
199 /** The options this bufferevent was constructed with */
200 enum bufferevent_options options;
201
202 /** Current reference count for this bufferevent. */
203 int refcnt;
204
205 /** Lock for this bufferevent. Shared by the inbuf and the outbuf.
206 * If NULL, locking is disabled. */
207 void *lock;
208
209 /** No matter how big our bucket gets, don't try to read more than this
210 * much in a single read operation. */
211 ev_ssize_t max_single_read;
212
213 /** No matter how big our bucket gets, don't try to write more than this
214 * much in a single write operation. */
215 ev_ssize_t max_single_write;
216
217 /** Rate-limiting information for this bufferevent */
218 struct bufferevent_rate_limit *rate_limiting;
219
220 /* Saved conn_addr, to extract IP address from it.
221 *
222 * Because some servers may reset/close connection without waiting clients,
223 * in that case we can't extract IP address even in close_cb.
224 * So we need to save it, just after we connected to remote server, or
225 * after resolving (to avoid extra dns requests during retrying, since UDP
226 * is slow) */
227 union {
228 struct sockaddr_in6 in6;
229 struct sockaddr_in in;
230 } conn_address;
231
232 struct evdns_getaddrinfo_request *dns_request;
233 };
234
235 /** Possible operations for a control callback. */
236 enum bufferevent_ctrl_op {
237 BEV_CTRL_SET_FD,
238 BEV_CTRL_GET_FD,
239 BEV_CTRL_GET_UNDERLYING,
240 BEV_CTRL_CANCEL_ALL
241 };
242
243 /** Possible data types for a control callback */
244 union bufferevent_ctrl_data {
245 void *ptr;
246 evutil_socket_t fd;
247 };
248
249 /**
250 Implementation table for a bufferevent: holds function pointers and other
251 information to make the various bufferevent types work.
252 */
253 struct bufferevent_ops {
254 /** The name of the bufferevent's type. */
255 const char *type;
256 /** At what offset into the implementation type will we find a
257 bufferevent structure?
258
259 Example: if the type is implemented as
260 struct bufferevent_x {
261 int extra_data;
262 struct bufferevent bev;
263 }
264 then mem_offset should be offsetof(struct bufferevent_x, bev)
265 */
266 off_t mem_offset;
267
268 /** Enables one or more of EV_READ|EV_WRITE on a bufferevent. Does
269 not need to adjust the 'enabled' field. Returns 0 on success, -1
270 on failure.
271 */
272 int (*enable)(struct bufferevent *, short);
273
274 /** Disables one or more of EV_READ|EV_WRITE on a bufferevent. Does
275 not need to adjust the 'enabled' field. Returns 0 on success, -1
276 on failure.
277 */
278 int (*disable)(struct bufferevent *, short);
279
280 /** Detatches the bufferevent from related data structures. Called as
281 * soon as its reference count reaches 0. */
282 void (*unlink)(struct bufferevent *);
283
284 /** Free any storage and deallocate any extra data or structures used
285 in this implementation. Called when the bufferevent is
286 finalized.
287 */
288 void (*destruct)(struct bufferevent *);
289
290 /** Called when the timeouts on the bufferevent have changed.*/
291 int (*adj_timeouts)(struct bufferevent *);
292
293 /** Called to flush data. */
294 int (*flush)(struct bufferevent *, short, enum bufferevent_flush_mode);
295
296 /** Called to access miscellaneous fields. */
297 int (*ctrl)(struct bufferevent *, enum bufferevent_ctrl_op, union bufferevent_ctrl_data *);
298
299 };
300
301 extern const struct bufferevent_ops bufferevent_ops_socket;
302 extern const struct bufferevent_ops bufferevent_ops_filter;
303 extern const struct bufferevent_ops bufferevent_ops_pair;
304
305 #define BEV_IS_SOCKET(bevp) ((bevp)->be_ops == &bufferevent_ops_socket)
306 #define BEV_IS_FILTER(bevp) ((bevp)->be_ops == &bufferevent_ops_filter)
307 #define BEV_IS_PAIR(bevp) ((bevp)->be_ops == &bufferevent_ops_pair)
308
309 #if defined(EVENT__HAVE_OPENSSL)
310 extern const struct bufferevent_ops bufferevent_ops_openssl;
311 #define BEV_IS_OPENSSL(bevp) ((bevp)->be_ops == &bufferevent_ops_openssl)
312 #else
313 #define BEV_IS_OPENSSL(bevp) 0
314 #endif
315
316 #ifdef _WIN32
317 extern const struct bufferevent_ops bufferevent_ops_async;
318 #define BEV_IS_ASYNC(bevp) ((bevp)->be_ops == &bufferevent_ops_async)
319 #else
320 #define BEV_IS_ASYNC(bevp) 0
321 #endif
322
323 /** Initialize the shared parts of a bufferevent. */
324 EVENT2_EXPORT_SYMBOL
325 int bufferevent_init_common_(struct bufferevent_private *, struct event_base *, const struct bufferevent_ops *, enum bufferevent_options options);
326
327 /** For internal use: temporarily stop all reads on bufev, until the conditions
328 * in 'what' are over. */
329 EVENT2_EXPORT_SYMBOL
330 void bufferevent_suspend_read_(struct bufferevent *bufev, bufferevent_suspend_flags what);
331 /** For internal use: clear the conditions 'what' on bufev, and re-enable
332 * reading if there are no conditions left. */
333 EVENT2_EXPORT_SYMBOL
334 void bufferevent_unsuspend_read_(struct bufferevent *bufev, bufferevent_suspend_flags what);
335
336 /** For internal use: temporarily stop all writes on bufev, until the conditions
337 * in 'what' are over. */
338 void bufferevent_suspend_write_(struct bufferevent *bufev, bufferevent_suspend_flags what);
339 /** For internal use: clear the conditions 'what' on bufev, and re-enable
340 * writing if there are no conditions left. */
341 void bufferevent_unsuspend_write_(struct bufferevent *bufev, bufferevent_suspend_flags what);
342
343 #define bufferevent_wm_suspend_read(b) \
344 bufferevent_suspend_read_((b), BEV_SUSPEND_WM)
345 #define bufferevent_wm_unsuspend_read(b) \
346 bufferevent_unsuspend_read_((b), BEV_SUSPEND_WM)
347
348 /*
349 Disable a bufferevent. Equivalent to bufferevent_disable(), but
350 first resets 'connecting' flag to force EV_WRITE down for sure.
351
352 XXXX this method will go away in the future; try not to add new users.
353 See comment in evhttp_connection_reset_() for discussion.
354
355 @param bufev the bufferevent to be disabled
356 @param event any combination of EV_READ | EV_WRITE.
357 @return 0 if successful, or -1 if an error occurred
358 @see bufferevent_disable()
359 */
360 EVENT2_EXPORT_SYMBOL
361 int bufferevent_disable_hard_(struct bufferevent *bufev, short event);
362
363 /** Internal: Set up locking on a bufferevent. If lock is set, use it.
364 * Otherwise, use a new lock. */
365 EVENT2_EXPORT_SYMBOL
366 int bufferevent_enable_locking_(struct bufferevent *bufev, void *lock);
367 /** Internal: backwards compat macro for the now public function
368 * Increment the reference count on bufev. */
369 #define bufferevent_incref_(bufev) bufferevent_incref(bufev)
370 /** Internal: Lock bufev and increase its reference count.
371 * unlocking it otherwise. */
372 EVENT2_EXPORT_SYMBOL
373 void bufferevent_incref_and_lock_(struct bufferevent *bufev);
374 /** Internal: backwards compat macro for the now public function
375 * Decrement the reference count on bufev. Returns 1 if it freed
376 * the bufferevent.*/
377 #define bufferevent_decref_(bufev) bufferevent_decref(bufev)
378
379 /** Internal: Drop the reference count on bufev, freeing as necessary, and
380 * unlocking it otherwise. Returns 1 if it freed the bufferevent. */
381 EVENT2_EXPORT_SYMBOL
382 int bufferevent_decref_and_unlock_(struct bufferevent *bufev);
383
384 /** Internal: If callbacks are deferred and we have a read callback, schedule
385 * a readcb. Otherwise just run the readcb. Ignores watermarks. */
386 EVENT2_EXPORT_SYMBOL
387 void bufferevent_run_readcb_(struct bufferevent *bufev, int options);
388 /** Internal: If callbacks are deferred and we have a write callback, schedule
389 * a writecb. Otherwise just run the writecb. Ignores watermarks. */
390 EVENT2_EXPORT_SYMBOL
391 void bufferevent_run_writecb_(struct bufferevent *bufev, int options);
392 /** Internal: If callbacks are deferred and we have an eventcb, schedule
393 * it to run with events "what". Otherwise just run the eventcb.
394 * See bufferevent_trigger_event for meaning of "options". */
395 EVENT2_EXPORT_SYMBOL
396 void bufferevent_run_eventcb_(struct bufferevent *bufev, short what, int options);
397
398 /** Internal: Run or schedule (if deferred or options contain
399 * BEV_TRIG_DEFER_CALLBACKS) I/O callbacks specified in iotype.
400 * Must already hold the bufev lock. Honors watermarks unless
401 * BEV_TRIG_IGNORE_WATERMARKS is in options. */
402 static inline void bufferevent_trigger_nolock_(struct bufferevent *bufev, short iotype, int options);
403
404 /* Making this inline since all of the common-case calls to this function in
405 * libevent use constant arguments. */
406 static inline void
bufferevent_trigger_nolock_(struct bufferevent * bufev,short iotype,int options)407 bufferevent_trigger_nolock_(struct bufferevent *bufev, short iotype, int options)
408 {
409 if ((iotype & EV_READ) && ((options & BEV_TRIG_IGNORE_WATERMARKS) ||
410 evbuffer_get_length(bufev->input) >= bufev->wm_read.low))
411 bufferevent_run_readcb_(bufev, options);
412 if ((iotype & EV_WRITE) && ((options & BEV_TRIG_IGNORE_WATERMARKS) ||
413 evbuffer_get_length(bufev->output) <= bufev->wm_write.low))
414 bufferevent_run_writecb_(bufev, options);
415 }
416
417 /** Internal: Add the event 'ev' with timeout tv, unless tv is set to 0, in
418 * which case add ev with no timeout. */
419 EVENT2_EXPORT_SYMBOL
420 int bufferevent_add_event_(struct event *ev, const struct timeval *tv);
421
422 /* =========
423 * These next functions implement timeouts for bufferevents that aren't doing
424 * anything else with ev_read and ev_write, to handle timeouts.
425 * ========= */
426 /** Internal use: Set up the ev_read and ev_write callbacks so that
427 * the other "generic_timeout" functions will work on it. Call this from
428 * the constructor function. */
429 EVENT2_EXPORT_SYMBOL
430 void bufferevent_init_generic_timeout_cbs_(struct bufferevent *bev);
431 /** Internal use: Add or delete the generic timeout events as appropriate.
432 * (If an event is enabled and a timeout is set, we add the event. Otherwise
433 * we delete it.) Call this from anything that changes the timeout values,
434 * that enabled EV_READ or EV_WRITE, or that disables EV_READ or EV_WRITE. */
435 EVENT2_EXPORT_SYMBOL
436 int bufferevent_generic_adj_timeouts_(struct bufferevent *bev);
437 EVENT2_EXPORT_SYMBOL
438 int bufferevent_generic_adj_existing_timeouts_(struct bufferevent *bev);
439
440 EVENT2_EXPORT_SYMBOL
441 enum bufferevent_options bufferevent_get_options_(struct bufferevent *bev);
442
443 EVENT2_EXPORT_SYMBOL
444 const struct sockaddr*
445 bufferevent_socket_get_conn_address_(struct bufferevent *bev);
446
447 EVENT2_EXPORT_SYMBOL
448 void
449 bufferevent_socket_set_conn_address_fd_(struct bufferevent *bev, evutil_socket_t fd);
450
451 EVENT2_EXPORT_SYMBOL
452 void
453 bufferevent_socket_set_conn_address_(struct bufferevent *bev, struct sockaddr *addr, size_t addrlen);
454
455
456 /** Internal use: We have just successfully read data into an inbuf, so
457 * reset the read timeout (if any). */
458 #define BEV_RESET_GENERIC_READ_TIMEOUT(bev) \
459 do { \
460 if (evutil_timerisset(&(bev)->timeout_read)) \
461 event_add(&(bev)->ev_read, &(bev)->timeout_read); \
462 } while (0)
463 /** Internal use: We have just successfully written data from an inbuf, so
464 * reset the read timeout (if any). */
465 #define BEV_RESET_GENERIC_WRITE_TIMEOUT(bev) \
466 do { \
467 if (evutil_timerisset(&(bev)->timeout_write)) \
468 event_add(&(bev)->ev_write, &(bev)->timeout_write); \
469 } while (0)
470 #define BEV_DEL_GENERIC_READ_TIMEOUT(bev) \
471 event_del(&(bev)->ev_read)
472 #define BEV_DEL_GENERIC_WRITE_TIMEOUT(bev) \
473 event_del(&(bev)->ev_write)
474
475
476 /** Internal: Given a bufferevent, return its corresponding
477 * bufferevent_private. */
478 #define BEV_UPCAST(b) EVUTIL_UPCAST((b), struct bufferevent_private, bev)
479
480 #ifdef EVENT__DISABLE_THREAD_SUPPORT
481 #define BEV_LOCK(b) EVUTIL_NIL_STMT_
482 #define BEV_UNLOCK(b) EVUTIL_NIL_STMT_
483 #else
484 /** Internal: Grab the lock (if any) on a bufferevent */
485 #define BEV_LOCK(b) do { \
486 struct bufferevent_private *locking = BEV_UPCAST(b); \
487 EVLOCK_LOCK(locking->lock, 0); \
488 } while (0)
489
490 /** Internal: Release the lock (if any) on a bufferevent */
491 #define BEV_UNLOCK(b) do { \
492 struct bufferevent_private *locking = BEV_UPCAST(b); \
493 EVLOCK_UNLOCK(locking->lock, 0); \
494 } while (0)
495 #endif
496
497
498 /* ==== For rate-limiting. */
499
500 EVENT2_EXPORT_SYMBOL
501 int bufferevent_decrement_write_buckets_(struct bufferevent_private *bev,
502 ev_ssize_t bytes);
503 EVENT2_EXPORT_SYMBOL
504 int bufferevent_decrement_read_buckets_(struct bufferevent_private *bev,
505 ev_ssize_t bytes);
506 EVENT2_EXPORT_SYMBOL
507 ev_ssize_t bufferevent_get_read_max_(struct bufferevent_private *bev);
508 EVENT2_EXPORT_SYMBOL
509 ev_ssize_t bufferevent_get_write_max_(struct bufferevent_private *bev);
510
511 int bufferevent_ratelim_init_(struct bufferevent_private *bev);
512
513 #ifdef __cplusplus
514 }
515 #endif
516
517
518 #endif /* BUFFEREVENT_INTERNAL_H_INCLUDED_ */
519