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 bufferevent_trigger_nolock_(struct bufferevent *bufev, short iotype, int options) 391 { 392 if ((iotype & EV_READ) && ((options & BEV_TRIG_IGNORE_WATERMARKS) || 393 evbuffer_get_length(bufev->input) >= bufev->wm_read.low)) 394 bufferevent_run_readcb_(bufev, options); 395 if ((iotype & EV_WRITE) && ((options & BEV_TRIG_IGNORE_WATERMARKS) || 396 evbuffer_get_length(bufev->output) <= bufev->wm_write.low)) 397 bufferevent_run_writecb_(bufev, options); 398 } 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_ */ 483