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_ 27 #define _BUFFEREVENT_INTERNAL_H_ 28 29 #ifdef __cplusplus 30 extern "C" { 31 #endif 32 33 #include "event2/event-config.h" 34 #include "event2/util.h" 35 #include "defer-internal.h" 36 #include "evthread-internal.h" 37 #include "event2/thread.h" 38 #include "ratelim-internal.h" 39 #include "event2/bufferevent_struct.h" 40 41 /* These flags are reasons that we might be declining to actually enable 42 reading or writing on a bufferevent. 43 */ 44 45 /* On a all bufferevents, for reading: used when we have read up to the 46 watermark value. 47 48 On a filtering bufferevent, for writing: used when the underlying 49 bufferevent's write buffer has been filled up to its watermark 50 value. 51 */ 52 #define BEV_SUSPEND_WM 0x01 53 /* On a base bufferevent: when we have emptied a bandwidth buckets */ 54 #define BEV_SUSPEND_BW 0x02 55 /* On a base bufferevent: when we have emptied the group's bandwidth bucket. */ 56 #define BEV_SUSPEND_BW_GROUP 0x04 57 /* On a socket bufferevent: can't do any operations while we're waiting for 58 * name lookup to finish. */ 59 #define BEV_SUSPEND_LOOKUP 0x08 60 /* On a base bufferevent, for reading: used when a filter has choked this 61 * (underlying) bufferevent because it has stopped reading from it. */ 62 #define BEV_SUSPEND_FILT_READ 0x10 63 64 typedef ev_uint16_t bufferevent_suspend_flags; 65 66 struct bufferevent_rate_limit_group { 67 /** List of all members in the group */ 68 TAILQ_HEAD(rlim_group_member_list, bufferevent_private) members; 69 /** Current limits for the group. */ 70 struct ev_token_bucket rate_limit; 71 struct ev_token_bucket_cfg rate_limit_cfg; 72 73 /** True iff we don't want to read from any member of the group.until 74 * the token bucket refills. */ 75 unsigned read_suspended : 1; 76 /** True iff we don't want to write from any member of the group.until 77 * the token bucket refills. */ 78 unsigned write_suspended : 1; 79 /** True iff we were unable to suspend one of the bufferevents in the 80 * group for reading the last time we tried, and we should try 81 * again. */ 82 unsigned pending_unsuspend_read : 1; 83 /** True iff we were unable to suspend one of the bufferevents in the 84 * group for writing the last time we tried, and we should try 85 * again. */ 86 unsigned pending_unsuspend_write : 1; 87 88 /*@{*/ 89 /** Total number of bytes read or written in this group since last 90 * reset. */ 91 ev_uint64_t total_read; 92 ev_uint64_t total_written; 93 /*@}*/ 94 95 /** The number of bufferevents in the group. */ 96 int n_members; 97 98 /** The smallest number of bytes that any member of the group should 99 * be limited to read or write at a time. */ 100 ev_ssize_t min_share; 101 ev_ssize_t configured_min_share; 102 103 /** Timeout event that goes off once a tick, when the bucket is ready 104 * to refill. */ 105 struct event master_refill_event; 106 /** Lock to protect the members of this group. This lock should nest 107 * within every bufferevent lock: if you are holding this lock, do 108 * not assume you can lock another bufferevent. */ 109 void *lock; 110 }; 111 112 /** Fields for rate-limiting a single bufferevent. */ 113 struct bufferevent_rate_limit { 114 /* Linked-list elements for storing this bufferevent_private in a 115 * group. 116 * 117 * Note that this field is supposed to be protected by the group 118 * lock */ 119 TAILQ_ENTRY(bufferevent_private) next_in_group; 120 /** The rate-limiting group for this bufferevent, or NULL if it is 121 * only rate-limited on its own. */ 122 struct bufferevent_rate_limit_group *group; 123 124 /* This bufferevent's current limits. */ 125 struct ev_token_bucket limit; 126 /* Pointer to the rate-limit configuration for this bufferevent. 127 * Can be shared. XXX reference-count this? */ 128 struct ev_token_bucket_cfg *cfg; 129 130 /* Timeout event used when one this bufferevent's buckets are 131 * empty. */ 132 struct event refill_bucket_event; 133 }; 134 135 /** Parts of the bufferevent structure that are shared among all bufferevent 136 * types, but not exposed in bufferevent_struct.h. */ 137 struct bufferevent_private { 138 /** The underlying bufferevent structure. */ 139 struct bufferevent bev; 140 141 /** Evbuffer callback to enforce watermarks on input. */ 142 struct evbuffer_cb_entry *read_watermarks_cb; 143 144 /** If set, we should free the lock when we free the bufferevent. */ 145 unsigned own_lock : 1; 146 147 /** Flag: set if we have deferred callbacks and a read callback is 148 * pending. */ 149 unsigned readcb_pending : 1; 150 /** Flag: set if we have deferred callbacks and a write callback is 151 * pending. */ 152 unsigned writecb_pending : 1; 153 /** Flag: set if we are currently busy connecting. */ 154 unsigned connecting : 1; 155 /** Flag: set if a connect failed prematurely; this is a hack for 156 * getting around the bufferevent abstraction. */ 157 unsigned connection_refused : 1; 158 /** Set to the events pending if we have deferred callbacks and 159 * an events callback is pending. */ 160 short eventcb_pending; 161 162 /** If set, read is suspended until one or more conditions are over. 163 * The actual value here is a bitfield of those conditions; see the 164 * BEV_SUSPEND_* flags above. */ 165 bufferevent_suspend_flags read_suspended; 166 167 /** If set, writing is suspended until one or more conditions are over. 168 * The actual value here is a bitfield of those conditions; see the 169 * BEV_SUSPEND_* flags above. */ 170 bufferevent_suspend_flags write_suspended; 171 172 /** Set to the current socket errno if we have deferred callbacks and 173 * an events callback is pending. */ 174 int errno_pending; 175 176 /** The DNS error code for bufferevent_socket_connect_hostname */ 177 int dns_error; 178 179 /** Used to implement deferred callbacks */ 180 struct deferred_cb deferred; 181 182 /** The options this bufferevent was constructed with */ 183 enum bufferevent_options options; 184 185 /** Current reference count for this bufferevent. */ 186 int refcnt; 187 188 /** Lock for this bufferevent. Shared by the inbuf and the outbuf. 189 * If NULL, locking is disabled. */ 190 void *lock; 191 192 /** Rate-limiting information for this bufferevent */ 193 struct bufferevent_rate_limit *rate_limiting; 194 }; 195 196 /** Possible operations for a control callback. */ 197 enum bufferevent_ctrl_op { 198 BEV_CTRL_SET_FD, 199 BEV_CTRL_GET_FD, 200 BEV_CTRL_GET_UNDERLYING, 201 BEV_CTRL_CANCEL_ALL 202 }; 203 204 /** Possible data types for a control callback */ 205 union bufferevent_ctrl_data { 206 void *ptr; 207 evutil_socket_t fd; 208 }; 209 210 /** 211 Implementation table for a bufferevent: holds function pointers and other 212 information to make the various bufferevent types work. 213 */ 214 struct bufferevent_ops { 215 /** The name of the bufferevent's type. */ 216 const char *type; 217 /** At what offset into the implementation type will we find a 218 bufferevent structure? 219 220 Example: if the type is implemented as 221 struct bufferevent_x { 222 int extra_data; 223 struct bufferevent bev; 224 } 225 then mem_offset should be offsetof(struct bufferevent_x, bev) 226 */ 227 off_t mem_offset; 228 229 /** Enables one or more of EV_READ|EV_WRITE on a bufferevent. Does 230 not need to adjust the 'enabled' field. Returns 0 on success, -1 231 on failure. 232 */ 233 int (*enable)(struct bufferevent *, short); 234 235 /** Disables one or more of EV_READ|EV_WRITE on a bufferevent. Does 236 not need to adjust the 'enabled' field. Returns 0 on success, -1 237 on failure. 238 */ 239 int (*disable)(struct bufferevent *, short); 240 241 /** Free any storage and deallocate any extra data or structures used 242 in this implementation. 243 */ 244 void (*destruct)(struct bufferevent *); 245 246 /** Called when the timeouts on the bufferevent have changed.*/ 247 int (*adj_timeouts)(struct bufferevent *); 248 249 /** Called to flush data. */ 250 int (*flush)(struct bufferevent *, short, enum bufferevent_flush_mode); 251 252 /** Called to access miscellaneous fields. */ 253 int (*ctrl)(struct bufferevent *, enum bufferevent_ctrl_op, union bufferevent_ctrl_data *); 254 255 }; 256 257 extern const struct bufferevent_ops bufferevent_ops_socket; 258 extern const struct bufferevent_ops bufferevent_ops_filter; 259 extern const struct bufferevent_ops bufferevent_ops_pair; 260 261 #define BEV_IS_SOCKET(bevp) ((bevp)->be_ops == &bufferevent_ops_socket) 262 #define BEV_IS_FILTER(bevp) ((bevp)->be_ops == &bufferevent_ops_filter) 263 #define BEV_IS_PAIR(bevp) ((bevp)->be_ops == &bufferevent_ops_pair) 264 265 #ifdef WIN32 266 extern const struct bufferevent_ops bufferevent_ops_async; 267 #define BEV_IS_ASYNC(bevp) ((bevp)->be_ops == &bufferevent_ops_async) 268 #else 269 #define BEV_IS_ASYNC(bevp) 0 270 #endif 271 272 /** Initialize the shared parts of a bufferevent. */ 273 int bufferevent_init_common(struct bufferevent_private *, struct event_base *, const struct bufferevent_ops *, enum bufferevent_options options); 274 275 /** For internal use: temporarily stop all reads on bufev, until the conditions 276 * in 'what' are over. */ 277 void bufferevent_suspend_read(struct bufferevent *bufev, bufferevent_suspend_flags what); 278 /** For internal use: clear the conditions 'what' on bufev, and re-enable 279 * reading if there are no conditions left. */ 280 void bufferevent_unsuspend_read(struct bufferevent *bufev, bufferevent_suspend_flags what); 281 282 /** For internal use: temporarily stop all writes on bufev, until the conditions 283 * in 'what' are over. */ 284 void bufferevent_suspend_write(struct bufferevent *bufev, bufferevent_suspend_flags what); 285 /** For internal use: clear the conditions 'what' on bufev, and re-enable 286 * writing if there are no conditions left. */ 287 void bufferevent_unsuspend_write(struct bufferevent *bufev, bufferevent_suspend_flags what); 288 289 #define bufferevent_wm_suspend_read(b) \ 290 bufferevent_suspend_read((b), BEV_SUSPEND_WM) 291 #define bufferevent_wm_unsuspend_read(b) \ 292 bufferevent_unsuspend_read((b), BEV_SUSPEND_WM) 293 294 /* 295 Disable a bufferevent. Equivalent to bufferevent_disable(), but 296 first resets 'connecting' flag to force EV_WRITE down for sure. 297 298 XXXX this method will go away in the future; try not to add new users. 299 See comment in evhttp_connection_reset() for discussion. 300 301 @param bufev the bufferevent to be disabled 302 @param event any combination of EV_READ | EV_WRITE. 303 @return 0 if successful, or -1 if an error occurred 304 @see bufferevent_disable() 305 */ 306 int bufferevent_disable_hard(struct bufferevent *bufev, short event); 307 308 /** Internal: Set up locking on a bufferevent. If lock is set, use it. 309 * Otherwise, use a new lock. */ 310 int bufferevent_enable_locking(struct bufferevent *bufev, void *lock); 311 /** Internal: Increment the reference count on bufev. */ 312 void bufferevent_incref(struct bufferevent *bufev); 313 /** Internal: Lock bufev and increase its reference count. 314 * unlocking it otherwise. */ 315 void _bufferevent_incref_and_lock(struct bufferevent *bufev); 316 /** Internal: Decrement the reference count on bufev. Returns 1 if it freed 317 * the bufferevent.*/ 318 int bufferevent_decref(struct bufferevent *bufev); 319 /** Internal: Drop the reference count on bufev, freeing as necessary, and 320 * unlocking it otherwise. Returns 1 if it freed the bufferevent. */ 321 int _bufferevent_decref_and_unlock(struct bufferevent *bufev); 322 323 /** Internal: If callbacks are deferred and we have a read callback, schedule 324 * a readcb. Otherwise just run the readcb. */ 325 void _bufferevent_run_readcb(struct bufferevent *bufev); 326 /** Internal: If callbacks are deferred and we have a write callback, schedule 327 * a writecb. Otherwise just run the writecb. */ 328 void _bufferevent_run_writecb(struct bufferevent *bufev); 329 /** Internal: If callbacks are deferred and we have an eventcb, schedule 330 * it to run with events "what". Otherwise just run the eventcb. */ 331 void _bufferevent_run_eventcb(struct bufferevent *bufev, short what); 332 333 /** Internal: Add the event 'ev' with timeout tv, unless tv is set to 0, in 334 * which case add ev with no timeout. */ 335 int _bufferevent_add_event(struct event *ev, const struct timeval *tv); 336 337 /* ========= 338 * These next functions implement timeouts for bufferevents that aren't doing 339 * anything else with ev_read and ev_write, to handle timeouts. 340 * ========= */ 341 /** Internal use: Set up the ev_read and ev_write callbacks so that 342 * the other "generic_timeout" functions will work on it. Call this from 343 * the constructor function. */ 344 void _bufferevent_init_generic_timeout_cbs(struct bufferevent *bev); 345 /** Internal use: Delete the ev_read and ev_write callbacks if they're pending. 346 * Call this from the destructor function. */ 347 int _bufferevent_del_generic_timeout_cbs(struct bufferevent *bev); 348 /** Internal use: Add or delete the generic timeout events as appropriate. 349 * (If an event is enabled and a timeout is set, we add the event. Otherwise 350 * we delete it.) Call this from anything that changes the timeout values, 351 * that enabled EV_READ or EV_WRITE, or that disables EV_READ or EV_WRITE. */ 352 int _bufferevent_generic_adj_timeouts(struct bufferevent *bev); 353 354 /** Internal use: We have just successfully read data into an inbuf, so 355 * reset the read timeout (if any). */ 356 #define BEV_RESET_GENERIC_READ_TIMEOUT(bev) \ 357 do { \ 358 if (evutil_timerisset(&(bev)->timeout_read)) \ 359 event_add(&(bev)->ev_read, &(bev)->timeout_read); \ 360 } while (0) 361 /** Internal use: We have just successfully written data from an inbuf, so 362 * reset the read timeout (if any). */ 363 #define BEV_RESET_GENERIC_WRITE_TIMEOUT(bev) \ 364 do { \ 365 if (evutil_timerisset(&(bev)->timeout_write)) \ 366 event_add(&(bev)->ev_write, &(bev)->timeout_write); \ 367 } while (0) 368 #define BEV_DEL_GENERIC_READ_TIMEOUT(bev) \ 369 event_del(&(bev)->ev_read) 370 #define BEV_DEL_GENERIC_WRITE_TIMEOUT(bev) \ 371 event_del(&(bev)->ev_write) 372 373 374 /** Internal: Given a bufferevent, return its corresponding 375 * bufferevent_private. */ 376 #define BEV_UPCAST(b) EVUTIL_UPCAST((b), struct bufferevent_private, bev) 377 378 #ifdef _EVENT_DISABLE_THREAD_SUPPORT 379 #define BEV_LOCK(b) _EVUTIL_NIL_STMT 380 #define BEV_UNLOCK(b) _EVUTIL_NIL_STMT 381 #else 382 /** Internal: Grab the lock (if any) on a bufferevent */ 383 #define BEV_LOCK(b) do { \ 384 struct bufferevent_private *locking = BEV_UPCAST(b); \ 385 EVLOCK_LOCK(locking->lock, 0); \ 386 } while (0) 387 388 /** Internal: Release the lock (if any) on a bufferevent */ 389 #define BEV_UNLOCK(b) do { \ 390 struct bufferevent_private *locking = BEV_UPCAST(b); \ 391 EVLOCK_UNLOCK(locking->lock, 0); \ 392 } while (0) 393 #endif 394 395 396 /* ==== For rate-limiting. */ 397 398 int _bufferevent_decrement_write_buckets(struct bufferevent_private *bev, 399 ev_ssize_t bytes); 400 int _bufferevent_decrement_read_buckets(struct bufferevent_private *bev, 401 ev_ssize_t bytes); 402 ev_ssize_t _bufferevent_get_read_max(struct bufferevent_private *bev); 403 ev_ssize_t _bufferevent_get_write_max(struct bufferevent_private *bev); 404 405 #ifdef __cplusplus 406 } 407 #endif 408 409 410 #endif /* _BUFFEREVENT_INTERNAL_H_ */ 411