Line data Source code
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 : #ifdef _WIN32
310 : extern const struct bufferevent_ops bufferevent_ops_async;
311 : #define BEV_IS_ASYNC(bevp) ((bevp)->be_ops == &bufferevent_ops_async)
312 : #else
313 : #define BEV_IS_ASYNC(bevp) 0
314 : #endif
315 :
316 : /** Initialize the shared parts of a bufferevent. */
317 : int bufferevent_init_common_(struct bufferevent_private *, struct event_base *, const struct bufferevent_ops *, enum bufferevent_options options);
318 :
319 : /** For internal use: temporarily stop all reads on bufev, until the conditions
320 : * in 'what' are over. */
321 : void bufferevent_suspend_read_(struct bufferevent *bufev, bufferevent_suspend_flags what);
322 : /** For internal use: clear the conditions 'what' on bufev, and re-enable
323 : * reading if there are no conditions left. */
324 : void bufferevent_unsuspend_read_(struct bufferevent *bufev, bufferevent_suspend_flags what);
325 :
326 : /** For internal use: temporarily stop all writes on bufev, until the conditions
327 : * in 'what' are over. */
328 : void bufferevent_suspend_write_(struct bufferevent *bufev, bufferevent_suspend_flags what);
329 : /** For internal use: clear the conditions 'what' on bufev, and re-enable
330 : * writing if there are no conditions left. */
331 : void bufferevent_unsuspend_write_(struct bufferevent *bufev, bufferevent_suspend_flags what);
332 :
333 : #define bufferevent_wm_suspend_read(b) \
334 : bufferevent_suspend_read_((b), BEV_SUSPEND_WM)
335 : #define bufferevent_wm_unsuspend_read(b) \
336 : bufferevent_unsuspend_read_((b), BEV_SUSPEND_WM)
337 :
338 : /*
339 : Disable a bufferevent. Equivalent to bufferevent_disable(), but
340 : first resets 'connecting' flag to force EV_WRITE down for sure.
341 :
342 : XXXX this method will go away in the future; try not to add new users.
343 : See comment in evhttp_connection_reset_() for discussion.
344 :
345 : @param bufev the bufferevent to be disabled
346 : @param event any combination of EV_READ | EV_WRITE.
347 : @return 0 if successful, or -1 if an error occurred
348 : @see bufferevent_disable()
349 : */
350 : int bufferevent_disable_hard_(struct bufferevent *bufev, short event);
351 :
352 : /** Internal: Set up locking on a bufferevent. If lock is set, use it.
353 : * Otherwise, use a new lock. */
354 : int bufferevent_enable_locking_(struct bufferevent *bufev, void *lock);
355 : /** Internal: backwards compat macro for the now public function
356 : * Increment the reference count on bufev. */
357 : #define bufferevent_incref_(bufev) bufferevent_incref(bufev)
358 : /** Internal: Lock bufev and increase its reference count.
359 : * unlocking it otherwise. */
360 : void bufferevent_incref_and_lock_(struct bufferevent *bufev);
361 : /** Internal: backwards compat macro for the now public function
362 : * Decrement the reference count on bufev. Returns 1 if it freed
363 : * the bufferevent.*/
364 : #define bufferevent_decref_(bufev) bufferevent_decref(bufev)
365 :
366 : /** Internal: Drop the reference count on bufev, freeing as necessary, and
367 : * unlocking it otherwise. Returns 1 if it freed the bufferevent. */
368 : int bufferevent_decref_and_unlock_(struct bufferevent *bufev);
369 :
370 : /** Internal: If callbacks are deferred and we have a read callback, schedule
371 : * a readcb. Otherwise just run the readcb. Ignores watermarks. */
372 : void bufferevent_run_readcb_(struct bufferevent *bufev, int options);
373 : /** Internal: If callbacks are deferred and we have a write callback, schedule
374 : * a writecb. Otherwise just run the writecb. Ignores watermarks. */
375 : void bufferevent_run_writecb_(struct bufferevent *bufev, int options);
376 : /** Internal: If callbacks are deferred and we have an eventcb, schedule
377 : * it to run with events "what". Otherwise just run the eventcb.
378 : * See bufferevent_trigger_event for meaning of "options". */
379 : void bufferevent_run_eventcb_(struct bufferevent *bufev, short what, int options);
380 :
381 : /** Internal: Run or schedule (if deferred or options contain
382 : * BEV_TRIG_DEFER_CALLBACKS) I/O callbacks specified in iotype.
383 : * Must already hold the bufev lock. Honors watermarks unless
384 : * BEV_TRIG_IGNORE_WATERMARKS is in options. */
385 : static inline void bufferevent_trigger_nolock_(struct bufferevent *bufev, short iotype, int options);
386 :
387 : /* Making this inline since all of the common-case calls to this function in
388 : * libevent use constant arguments. */
389 : static inline void
390 0 : bufferevent_trigger_nolock_(struct bufferevent *bufev, short iotype, int options)
391 : {
392 0 : if ((iotype & EV_READ) && ((options & BEV_TRIG_IGNORE_WATERMARKS) ||
393 0 : evbuffer_get_length(bufev->input) >= bufev->wm_read.low))
394 0 : bufferevent_run_readcb_(bufev, options);
395 0 : if ((iotype & EV_WRITE) && ((options & BEV_TRIG_IGNORE_WATERMARKS) ||
396 0 : evbuffer_get_length(bufev->output) <= bufev->wm_write.low))
397 0 : bufferevent_run_writecb_(bufev, options);
398 0 : }
399 :
400 : /** Internal: Add the event 'ev' with timeout tv, unless tv is set to 0, in
401 : * which case add ev with no timeout. */
402 : int bufferevent_add_event_(struct event *ev, const struct timeval *tv);
403 :
404 : /* =========
405 : * These next functions implement timeouts for bufferevents that aren't doing
406 : * anything else with ev_read and ev_write, to handle timeouts.
407 : * ========= */
408 : /** Internal use: Set up the ev_read and ev_write callbacks so that
409 : * the other "generic_timeout" functions will work on it. Call this from
410 : * the constructor function. */
411 : void bufferevent_init_generic_timeout_cbs_(struct bufferevent *bev);
412 : /** Internal use: Add or delete the generic timeout events as appropriate.
413 : * (If an event is enabled and a timeout is set, we add the event. Otherwise
414 : * we delete it.) Call this from anything that changes the timeout values,
415 : * that enabled EV_READ or EV_WRITE, or that disables EV_READ or EV_WRITE. */
416 : int bufferevent_generic_adj_timeouts_(struct bufferevent *bev);
417 : int bufferevent_generic_adj_existing_timeouts_(struct bufferevent *bev);
418 :
419 : enum bufferevent_options bufferevent_get_options_(struct bufferevent *bev);
420 :
421 : const struct sockaddr*
422 : bufferevent_socket_get_conn_address_(struct bufferevent *bev);
423 :
424 : /** Internal use: We have just successfully read data into an inbuf, so
425 : * reset the read timeout (if any). */
426 : #define BEV_RESET_GENERIC_READ_TIMEOUT(bev) \
427 : do { \
428 : if (evutil_timerisset(&(bev)->timeout_read)) \
429 : event_add(&(bev)->ev_read, &(bev)->timeout_read); \
430 : } while (0)
431 : /** Internal use: We have just successfully written data from an inbuf, so
432 : * reset the read timeout (if any). */
433 : #define BEV_RESET_GENERIC_WRITE_TIMEOUT(bev) \
434 : do { \
435 : if (evutil_timerisset(&(bev)->timeout_write)) \
436 : event_add(&(bev)->ev_write, &(bev)->timeout_write); \
437 : } while (0)
438 : #define BEV_DEL_GENERIC_READ_TIMEOUT(bev) \
439 : event_del(&(bev)->ev_read)
440 : #define BEV_DEL_GENERIC_WRITE_TIMEOUT(bev) \
441 : event_del(&(bev)->ev_write)
442 :
443 :
444 : /** Internal: Given a bufferevent, return its corresponding
445 : * bufferevent_private. */
446 : #define BEV_UPCAST(b) EVUTIL_UPCAST((b), struct bufferevent_private, bev)
447 :
448 : #ifdef EVENT__DISABLE_THREAD_SUPPORT
449 : #define BEV_LOCK(b) EVUTIL_NIL_STMT_
450 : #define BEV_UNLOCK(b) EVUTIL_NIL_STMT_
451 : #else
452 : /** Internal: Grab the lock (if any) on a bufferevent */
453 : #define BEV_LOCK(b) do { \
454 : struct bufferevent_private *locking = BEV_UPCAST(b); \
455 : EVLOCK_LOCK(locking->lock, 0); \
456 : } while (0)
457 :
458 : /** Internal: Release the lock (if any) on a bufferevent */
459 : #define BEV_UNLOCK(b) do { \
460 : struct bufferevent_private *locking = BEV_UPCAST(b); \
461 : EVLOCK_UNLOCK(locking->lock, 0); \
462 : } while (0)
463 : #endif
464 :
465 :
466 : /* ==== For rate-limiting. */
467 :
468 : int bufferevent_decrement_write_buckets_(struct bufferevent_private *bev,
469 : ev_ssize_t bytes);
470 : int bufferevent_decrement_read_buckets_(struct bufferevent_private *bev,
471 : ev_ssize_t bytes);
472 : ev_ssize_t bufferevent_get_read_max_(struct bufferevent_private *bev);
473 : ev_ssize_t bufferevent_get_write_max_(struct bufferevent_private *bev);
474 :
475 : int bufferevent_ratelim_init_(struct bufferevent_private *bev);
476 :
477 : #ifdef __cplusplus
478 : }
479 : #endif
480 :
481 :
482 : #endif /* BUFFEREVENT_INTERNAL_H_INCLUDED_ */
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