1 /* $NetBSD: bufferevent-internal.h,v 1.2 2013/04/11 16:56:41 christos Exp $ */ 2 /* 3 * Copyright (c) 2008-2012 Niels Provos and Nick Mathewson 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. The name of the author may not be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 #ifndef _BUFFEREVENT_INTERNAL_H_ 28 #define _BUFFEREVENT_INTERNAL_H_ 29 30 #ifdef __cplusplus 31 extern "C" { 32 #endif 33 34 #include "event2/event-config.h" 35 #include "event2/util.h" 36 #include "defer-internal.h" 37 #include "evthread-internal.h" 38 #include "event2/thread.h" 39 #include "ratelim-internal.h" 40 #include "event2/bufferevent_struct.h" 41 42 /* These flags are reasons that we might be declining to actually enable 43 reading or writing on a bufferevent. 44 */ 45 46 /* On a all bufferevents, for reading: used when we have read up to the 47 watermark value. 48 49 On a filtering bufferevent, for writing: used when the underlying 50 bufferevent's write buffer has been filled up to its watermark 51 value. 52 */ 53 #define BEV_SUSPEND_WM 0x01 54 /* On a base bufferevent: when we have emptied a bandwidth buckets */ 55 #define BEV_SUSPEND_BW 0x02 56 /* On a base bufferevent: when we have emptied the group's bandwidth bucket. */ 57 #define BEV_SUSPEND_BW_GROUP 0x04 58 /* On a socket bufferevent: can't do any operations while we're waiting for 59 * name lookup to finish. */ 60 #define BEV_SUSPEND_LOOKUP 0x08 61 /* On a base bufferevent, for reading: used when a filter has choked this 62 * (underlying) bufferevent because it has stopped reading from it. */ 63 #define BEV_SUSPEND_FILT_READ 0x10 64 65 typedef ev_uint16_t bufferevent_suspend_flags; 66 67 struct bufferevent_rate_limit_group { 68 /** List of all members in the group */ 69 TAILQ_HEAD(rlim_group_member_list, bufferevent_private) members; 70 /** Current limits for the group. */ 71 struct ev_token_bucket rate_limit; 72 struct ev_token_bucket_cfg rate_limit_cfg; 73 74 /** True iff we don't want to read from any member of the group.until 75 * the token bucket refills. */ 76 unsigned read_suspended : 1; 77 /** True iff we don't want to write from any member of the group.until 78 * the token bucket refills. */ 79 unsigned write_suspended : 1; 80 /** True iff we were unable to suspend one of the bufferevents in the 81 * group for reading the last time we tried, and we should try 82 * again. */ 83 unsigned pending_unsuspend_read : 1; 84 /** True iff we were unable to suspend one of the bufferevents in the 85 * group for writing the last time we tried, and we should try 86 * again. */ 87 unsigned pending_unsuspend_write : 1; 88 89 /*@{*/ 90 /** Total number of bytes read or written in this group since last 91 * reset. */ 92 ev_uint64_t total_read; 93 ev_uint64_t total_written; 94 /*@}*/ 95 96 /** The number of bufferevents in the group. */ 97 int n_members; 98 99 /** The smallest number of bytes that any member of the group should 100 * be limited to read or write at a time. */ 101 ev_ssize_t min_share; 102 ev_ssize_t configured_min_share; 103 104 /** Timeout event that goes off once a tick, when the bucket is ready 105 * to refill. */ 106 struct event master_refill_event; 107 /** Lock to protect the members of this group. This lock should nest 108 * within every bufferevent lock: if you are holding this lock, do 109 * not assume you can lock another bufferevent. */ 110 void *lock; 111 }; 112 113 /** Fields for rate-limiting a single bufferevent. */ 114 struct bufferevent_rate_limit { 115 /* Linked-list elements for storing this bufferevent_private in a 116 * group. 117 * 118 * Note that this field is supposed to be protected by the group 119 * lock */ 120 TAILQ_ENTRY(bufferevent_private) next_in_group; 121 /** The rate-limiting group for this bufferevent, or NULL if it is 122 * only rate-limited on its own. */ 123 struct bufferevent_rate_limit_group *group; 124 125 /* This bufferevent's current limits. */ 126 struct ev_token_bucket limit; 127 /* Pointer to the rate-limit configuration for this bufferevent. 128 * Can be shared. XXX reference-count this? */ 129 struct ev_token_bucket_cfg *cfg; 130 131 /* Timeout event used when one this bufferevent's buckets are 132 * empty. */ 133 struct event refill_bucket_event; 134 }; 135 136 /** Parts of the bufferevent structure that are shared among all bufferevent 137 * types, but not exposed in bufferevent_struct.h. */ 138 struct bufferevent_private { 139 /** The underlying bufferevent structure. */ 140 struct bufferevent bev; 141 142 /** Evbuffer callback to enforce watermarks on input. */ 143 struct evbuffer_cb_entry *read_watermarks_cb; 144 145 /** If set, we should free the lock when we free the bufferevent. */ 146 unsigned own_lock : 1; 147 148 /** Flag: set if we have deferred callbacks and a read callback is 149 * pending. */ 150 unsigned readcb_pending : 1; 151 /** Flag: set if we have deferred callbacks and a write callback is 152 * pending. */ 153 unsigned writecb_pending : 1; 154 /** Flag: set if we are currently busy connecting. */ 155 unsigned connecting : 1; 156 /** Flag: set if a connect failed prematurely; this is a hack for 157 * getting around the bufferevent abstraction. */ 158 unsigned connection_refused : 1; 159 /** Set to the events pending if we have deferred callbacks and 160 * an events callback is pending. */ 161 short eventcb_pending; 162 163 /** If set, read is suspended until one or more conditions are over. 164 * The actual value here is a bitfield of those conditions; see the 165 * BEV_SUSPEND_* flags above. */ 166 bufferevent_suspend_flags read_suspended; 167 168 /** If set, writing is suspended until one or more conditions are over. 169 * The actual value here is a bitfield of those conditions; see the 170 * BEV_SUSPEND_* flags above. */ 171 bufferevent_suspend_flags write_suspended; 172 173 /** Set to the current socket errno if we have deferred callbacks and 174 * an events callback is pending. */ 175 int errno_pending; 176 177 /** The DNS error code for bufferevent_socket_connect_hostname */ 178 int dns_error; 179 180 /** Used to implement deferred callbacks */ 181 struct deferred_cb deferred; 182 183 /** The options this bufferevent was constructed with */ 184 enum bufferevent_options options; 185 186 /** Current reference count for this bufferevent. */ 187 int refcnt; 188 189 /** Lock for this bufferevent. Shared by the inbuf and the outbuf. 190 * If NULL, locking is disabled. */ 191 void *lock; 192 193 /** Rate-limiting information for this bufferevent */ 194 struct bufferevent_rate_limit *rate_limiting; 195 }; 196 197 /** Possible operations for a control callback. */ 198 enum bufferevent_ctrl_op { 199 BEV_CTRL_SET_FD, 200 BEV_CTRL_GET_FD, 201 BEV_CTRL_GET_UNDERLYING, 202 BEV_CTRL_CANCEL_ALL 203 }; 204 205 /** Possible data types for a control callback */ 206 union bufferevent_ctrl_data { 207 void *ptr; 208 evutil_socket_t fd; 209 }; 210 211 /** 212 Implementation table for a bufferevent: holds function pointers and other 213 information to make the various bufferevent types work. 214 */ 215 struct bufferevent_ops { 216 /** The name of the bufferevent's type. */ 217 const char *type; 218 /** At what offset into the implementation type will we find a 219 bufferevent structure? 220 221 Example: if the type is implemented as 222 struct bufferevent_x { 223 int extra_data; 224 struct bufferevent bev; 225 } 226 then mem_offset should be offsetof(struct bufferevent_x, bev) 227 */ 228 off_t mem_offset; 229 230 /** Enables one or more of EV_READ|EV_WRITE on a bufferevent. Does 231 not need to adjust the 'enabled' field. Returns 0 on success, -1 232 on failure. 233 */ 234 int (*enable)(struct bufferevent *, short); 235 236 /** Disables one or more of EV_READ|EV_WRITE on a bufferevent. Does 237 not need to adjust the 'enabled' field. Returns 0 on success, -1 238 on failure. 239 */ 240 int (*disable)(struct bufferevent *, short); 241 242 /** Free any storage and deallocate any extra data or structures used 243 in this implementation. 244 */ 245 void (*destruct)(struct bufferevent *); 246 247 /** Called when the timeouts on the bufferevent have changed.*/ 248 int (*adj_timeouts)(struct bufferevent *); 249 250 /** Called to flush data. */ 251 int (*flush)(struct bufferevent *, short, enum bufferevent_flush_mode); 252 253 /** Called to access miscellaneous fields. */ 254 int (*ctrl)(struct bufferevent *, enum bufferevent_ctrl_op, union bufferevent_ctrl_data *); 255 256 }; 257 258 extern const struct bufferevent_ops bufferevent_ops_socket; 259 extern const struct bufferevent_ops bufferevent_ops_filter; 260 extern const struct bufferevent_ops bufferevent_ops_pair; 261 262 #define BEV_IS_SOCKET(bevp) ((bevp)->be_ops == &bufferevent_ops_socket) 263 #define BEV_IS_FILTER(bevp) ((bevp)->be_ops == &bufferevent_ops_filter) 264 #define BEV_IS_PAIR(bevp) ((bevp)->be_ops == &bufferevent_ops_pair) 265 266 #ifdef WIN32 267 extern const struct bufferevent_ops bufferevent_ops_async; 268 #define BEV_IS_ASYNC(bevp) ((bevp)->be_ops == &bufferevent_ops_async) 269 #else 270 #define BEV_IS_ASYNC(bevp) 0 271 #endif 272 273 /** Initialize the shared parts of a bufferevent. */ 274 int bufferevent_init_common(struct bufferevent_private *, struct event_base *, const struct bufferevent_ops *, enum bufferevent_options options); 275 276 /** For internal use: temporarily stop all reads on bufev, until the conditions 277 * in 'what' are over. */ 278 void bufferevent_suspend_read(struct bufferevent *bufev, bufferevent_suspend_flags what); 279 /** For internal use: clear the conditions 'what' on bufev, and re-enable 280 * reading if there are no conditions left. */ 281 void bufferevent_unsuspend_read(struct bufferevent *bufev, bufferevent_suspend_flags what); 282 283 /** For internal use: temporarily stop all writes on bufev, until the conditions 284 * in 'what' are over. */ 285 void bufferevent_suspend_write(struct bufferevent *bufev, bufferevent_suspend_flags what); 286 /** For internal use: clear the conditions 'what' on bufev, and re-enable 287 * writing if there are no conditions left. */ 288 void bufferevent_unsuspend_write(struct bufferevent *bufev, bufferevent_suspend_flags what); 289 290 #define bufferevent_wm_suspend_read(b) \ 291 bufferevent_suspend_read((b), BEV_SUSPEND_WM) 292 #define bufferevent_wm_unsuspend_read(b) \ 293 bufferevent_unsuspend_read((b), BEV_SUSPEND_WM) 294 295 /* 296 Disable a bufferevent. Equivalent to bufferevent_disable(), but 297 first resets 'connecting' flag to force EV_WRITE down for sure. 298 299 XXXX this method will go away in the future; try not to add new users. 300 See comment in evhttp_connection_reset() for discussion. 301 302 @param bufev the bufferevent to be disabled 303 @param event any combination of EV_READ | EV_WRITE. 304 @return 0 if successful, or -1 if an error occurred 305 @see bufferevent_disable() 306 */ 307 int bufferevent_disable_hard(struct bufferevent *bufev, short event); 308 309 /** Internal: Set up locking on a bufferevent. If lock is set, use it. 310 * Otherwise, use a new lock. */ 311 int bufferevent_enable_locking(struct bufferevent *bufev, void *lock); 312 /** Internal: Increment the reference count on bufev. */ 313 void bufferevent_incref(struct bufferevent *bufev); 314 /** Internal: Lock bufev and increase its reference count. 315 * unlocking it otherwise. */ 316 void _bufferevent_incref_and_lock(struct bufferevent *bufev); 317 /** Internal: Decrement the reference count on bufev. Returns 1 if it freed 318 * the bufferevent.*/ 319 int bufferevent_decref(struct bufferevent *bufev); 320 /** Internal: Drop the reference count on bufev, freeing as necessary, and 321 * unlocking it otherwise. Returns 1 if it freed the bufferevent. */ 322 int _bufferevent_decref_and_unlock(struct bufferevent *bufev); 323 324 /** Internal: If callbacks are deferred and we have a read callback, schedule 325 * a readcb. Otherwise just run the readcb. */ 326 void _bufferevent_run_readcb(struct bufferevent *bufev); 327 /** Internal: If callbacks are deferred and we have a write callback, schedule 328 * a writecb. Otherwise just run the writecb. */ 329 void _bufferevent_run_writecb(struct bufferevent *bufev); 330 /** Internal: If callbacks are deferred and we have an eventcb, schedule 331 * it to run with events "what". Otherwise just run the eventcb. */ 332 void _bufferevent_run_eventcb(struct bufferevent *bufev, short what); 333 334 /** Internal: Add the event 'ev' with timeout tv, unless tv is set to 0, in 335 * which case add ev with no timeout. */ 336 int _bufferevent_add_event(struct event *ev, const struct timeval *tv); 337 338 /* ========= 339 * These next functions implement timeouts for bufferevents that aren't doing 340 * anything else with ev_read and ev_write, to handle timeouts. 341 * ========= */ 342 /** Internal use: Set up the ev_read and ev_write callbacks so that 343 * the other "generic_timeout" functions will work on it. Call this from 344 * the constructor function. */ 345 void _bufferevent_init_generic_timeout_cbs(struct bufferevent *bev); 346 /** Internal use: Delete the ev_read and ev_write callbacks if they're pending. 347 * Call this from the destructor function. */ 348 int _bufferevent_del_generic_timeout_cbs(struct bufferevent *bev); 349 /** Internal use: Add or delete the generic timeout events as appropriate. 350 * (If an event is enabled and a timeout is set, we add the event. Otherwise 351 * we delete it.) Call this from anything that changes the timeout values, 352 * that enabled EV_READ or EV_WRITE, or that disables EV_READ or EV_WRITE. */ 353 int _bufferevent_generic_adj_timeouts(struct bufferevent *bev); 354 355 /** Internal use: We have just successfully read data into an inbuf, so 356 * reset the read timeout (if any). */ 357 #define BEV_RESET_GENERIC_READ_TIMEOUT(bev) \ 358 do { \ 359 if (evutil_timerisset(&(bev)->timeout_read)) \ 360 event_add(&(bev)->ev_read, &(bev)->timeout_read); \ 361 } while (/*CONSTCOND*/0) 362 /** Internal use: We have just successfully written data from an inbuf, so 363 * reset the read timeout (if any). */ 364 #define BEV_RESET_GENERIC_WRITE_TIMEOUT(bev) \ 365 do { \ 366 if (evutil_timerisset(&(bev)->timeout_write)) \ 367 event_add(&(bev)->ev_write, &(bev)->timeout_write); \ 368 } while (/*CONSTCOND*/0) 369 #define BEV_DEL_GENERIC_READ_TIMEOUT(bev) \ 370 event_del(&(bev)->ev_read) 371 #define BEV_DEL_GENERIC_WRITE_TIMEOUT(bev) \ 372 event_del(&(bev)->ev_write) 373 374 375 /** Internal: Given a bufferevent, return its corresponding 376 * bufferevent_private. */ 377 #define BEV_UPCAST(b) EVUTIL_UPCAST((b), struct bufferevent_private, bev) 378 379 #ifdef _EVENT_DISABLE_THREAD_SUPPORT 380 #define BEV_LOCK(b) _EVUTIL_NIL_STMT 381 #define BEV_UNLOCK(b) _EVUTIL_NIL_STMT 382 #else 383 /** Internal: Grab the lock (if any) on a bufferevent */ 384 #define BEV_LOCK(b) do { \ 385 struct bufferevent_private *locking = BEV_UPCAST(b); \ 386 EVLOCK_LOCK(locking->lock, 0); \ 387 } while (/*CONSTCOND*/0) 388 389 /** Internal: Release the lock (if any) on a bufferevent */ 390 #define BEV_UNLOCK(b) do { \ 391 struct bufferevent_private *locking = BEV_UPCAST(b); \ 392 EVLOCK_UNLOCK(locking->lock, 0); \ 393 } while (/*CONSTCOND*/0) 394 #endif 395 396 397 /* ==== For rate-limiting. */ 398 399 int _bufferevent_decrement_write_buckets(struct bufferevent_private *bev, 400 ev_ssize_t bytes); 401 int _bufferevent_decrement_read_buckets(struct bufferevent_private *bev, 402 ev_ssize_t bytes); 403 ev_ssize_t _bufferevent_get_read_max(struct bufferevent_private *bev); 404 ev_ssize_t _bufferevent_get_write_max(struct bufferevent_private *bev); 405 406 #ifdef __cplusplus 407 } 408 #endif 409 410 411 #endif /* _BUFFEREVENT_INTERNAL_H_ */ 412