1 /* $NetBSD: bufferevent-internal.h,v 1.3 2017/01/31 23:17:39 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_INCLUDED_ 28 #define BUFFEREVENT_INTERNAL_H_INCLUDED_ 29 30 #ifdef __cplusplus 31 extern "C" { 32 #endif 33 34 #include "event2/event-config.h" 35 #include "event2/event_struct.h" 36 #include "evconfig-private.h" 37 #include "event2/util.h" 38 #include "defer-internal.h" 39 #include "evthread-internal.h" 40 #include "event2/thread.h" 41 #include "ratelim-internal.h" 42 #include "event2/bufferevent_struct.h" 43 44 #include "ipv6-internal.h" 45 #ifdef _WIN32 46 #include <ws2tcpip.h> 47 #endif 48 #ifdef EVENT__HAVE_NETINET_IN_H 49 #include <netinet/in.h> 50 #endif 51 #ifdef EVENT__HAVE_NETINET_IN6_H 52 #include <netinet/in6.h> 53 #endif 54 55 /* These flags are reasons that we might be declining to actually enable 56 reading or writing on a bufferevent. 57 */ 58 59 /* On a all bufferevents, for reading: used when we have read up to the 60 watermark value. 61 62 On a filtering bufferevent, for writing: used when the underlying 63 bufferevent's write buffer has been filled up to its watermark 64 value. 65 */ 66 #define BEV_SUSPEND_WM 0x01 67 /* On a base bufferevent: when we have emptied a bandwidth buckets */ 68 #define BEV_SUSPEND_BW 0x02 69 /* On a base bufferevent: when we have emptied the group's bandwidth bucket. */ 70 #define BEV_SUSPEND_BW_GROUP 0x04 71 /* On a socket bufferevent: can't do any operations while we're waiting for 72 * name lookup to finish. */ 73 #define BEV_SUSPEND_LOOKUP 0x08 74 /* On a base bufferevent, for reading: used when a filter has choked this 75 * (underlying) bufferevent because it has stopped reading from it. */ 76 #define BEV_SUSPEND_FILT_READ 0x10 77 78 typedef ev_uint16_t bufferevent_suspend_flags; 79 80 struct bufferevent_rate_limit_group { 81 /** List of all members in the group */ 82 LIST_HEAD(rlim_group_member_list, bufferevent_private) members; 83 /** Current limits for the group. */ 84 struct ev_token_bucket rate_limit; 85 struct ev_token_bucket_cfg rate_limit_cfg; 86 87 /** True iff we don't want to read from any member of the group.until 88 * the token bucket refills. */ 89 unsigned read_suspended : 1; 90 /** True iff we don't want to write from any member of the group.until 91 * the token bucket refills. */ 92 unsigned write_suspended : 1; 93 /** True iff we were unable to suspend one of the bufferevents in the 94 * group for reading the last time we tried, and we should try 95 * again. */ 96 unsigned pending_unsuspend_read : 1; 97 /** True iff we were unable to suspend one of the bufferevents in the 98 * group for writing the last time we tried, and we should try 99 * again. */ 100 unsigned pending_unsuspend_write : 1; 101 102 /*@{*/ 103 /** Total number of bytes read or written in this group since last 104 * reset. */ 105 ev_uint64_t total_read; 106 ev_uint64_t total_written; 107 /*@}*/ 108 109 /** The number of bufferevents in the group. */ 110 int n_members; 111 112 /** The smallest number of bytes that any member of the group should 113 * be limited to read or write at a time. */ 114 ev_ssize_t min_share; 115 ev_ssize_t configured_min_share; 116 117 /** Timeout event that goes off once a tick, when the bucket is ready 118 * to refill. */ 119 struct event master_refill_event; 120 121 /** Seed for weak random number generator. Protected by 'lock' */ 122 struct evutil_weakrand_state weakrand_seed; 123 124 /** Lock to protect the members of this group. This lock should nest 125 * within every bufferevent lock: if you are holding this lock, do 126 * not assume you can lock another bufferevent. */ 127 void *lock; 128 }; 129 130 /** Fields for rate-limiting a single bufferevent. */ 131 struct bufferevent_rate_limit { 132 /* Linked-list elements for storing this bufferevent_private in a 133 * group. 134 * 135 * Note that this field is supposed to be protected by the group 136 * lock */ 137 LIST_ENTRY(bufferevent_private) next_in_group; 138 /** The rate-limiting group for this bufferevent, or NULL if it is 139 * only rate-limited on its own. */ 140 struct bufferevent_rate_limit_group *group; 141 142 /* This bufferevent's current limits. */ 143 struct ev_token_bucket limit; 144 /* Pointer to the rate-limit configuration for this bufferevent. 145 * Can be shared. XXX reference-count this? */ 146 struct ev_token_bucket_cfg *cfg; 147 148 /* Timeout event used when one this bufferevent's buckets are 149 * empty. */ 150 struct event refill_bucket_event; 151 }; 152 153 /** Parts of the bufferevent structure that are shared among all bufferevent 154 * types, but not exposed in bufferevent_struct.h. */ 155 struct bufferevent_private { 156 /** The underlying bufferevent structure. */ 157 struct bufferevent bev; 158 159 /** Evbuffer callback to enforce watermarks on input. */ 160 struct evbuffer_cb_entry *read_watermarks_cb; 161 162 /** If set, we should free the lock when we free the bufferevent. */ 163 unsigned own_lock : 1; 164 165 /** Flag: set if we have deferred callbacks and a read callback is 166 * pending. */ 167 unsigned readcb_pending : 1; 168 /** Flag: set if we have deferred callbacks and a write callback is 169 * pending. */ 170 unsigned writecb_pending : 1; 171 /** Flag: set if we are currently busy connecting. */ 172 unsigned connecting : 1; 173 /** Flag: set if a connect failed prematurely; this is a hack for 174 * getting around the bufferevent abstraction. */ 175 unsigned connection_refused : 1; 176 /** Set to the events pending if we have deferred callbacks and 177 * an events callback is pending. */ 178 short eventcb_pending; 179 180 /** If set, read is suspended until one or more conditions are over. 181 * The actual value here is a bitfield of those conditions; see the 182 * BEV_SUSPEND_* flags above. */ 183 bufferevent_suspend_flags read_suspended; 184 185 /** If set, writing is suspended until one or more conditions are over. 186 * The actual value here is a bitfield of those conditions; see the 187 * BEV_SUSPEND_* flags above. */ 188 bufferevent_suspend_flags write_suspended; 189 190 /** Set to the current socket errno if we have deferred callbacks and 191 * an events callback is pending. */ 192 int errno_pending; 193 194 /** The DNS error code for bufferevent_socket_connect_hostname */ 195 int dns_error; 196 197 /** Used to implement deferred callbacks */ 198 struct event_callback deferred; 199 200 /** The options this bufferevent was constructed with */ 201 enum bufferevent_options options; 202 203 /** Current reference count for this bufferevent. */ 204 int refcnt; 205 206 /** Lock for this bufferevent. Shared by the inbuf and the outbuf. 207 * If NULL, locking is disabled. */ 208 void *lock; 209 210 /** No matter how big our bucket gets, don't try to read more than this 211 * much in a single read operation. */ 212 ev_ssize_t max_single_read; 213 214 /** No matter how big our bucket gets, don't try to write more than this 215 * much in a single write operation. */ 216 ev_ssize_t max_single_write; 217 218 /** Rate-limiting information for this bufferevent */ 219 struct bufferevent_rate_limit *rate_limiting; 220 221 /* Saved conn_addr, to extract IP address from it. 222 * 223 * Because some servers may reset/close connection without waiting clients, 224 * in that case we can't extract IP address even in close_cb. 225 * So we need to save it, just after we connected to remote server, or 226 * after resolving (to avoid extra dns requests during retrying, since UDP 227 * is slow) */ 228 union { 229 struct sockaddr_in6 in6; 230 struct sockaddr_in in; 231 } conn_address; 232 233 struct evdns_getaddrinfo_request *dns_request; 234 }; 235 236 /** Possible operations for a control callback. */ 237 enum bufferevent_ctrl_op { 238 BEV_CTRL_SET_FD, 239 BEV_CTRL_GET_FD, 240 BEV_CTRL_GET_UNDERLYING, 241 BEV_CTRL_CANCEL_ALL 242 }; 243 244 /** Possible data types for a control callback */ 245 union bufferevent_ctrl_data { 246 void *ptr; 247 evutil_socket_t fd; 248 }; 249 250 /** 251 Implementation table for a bufferevent: holds function pointers and other 252 information to make the various bufferevent types work. 253 */ 254 struct bufferevent_ops { 255 /** The name of the bufferevent's type. */ 256 const char *type; 257 /** At what offset into the implementation type will we find a 258 bufferevent structure? 259 260 Example: if the type is implemented as 261 struct bufferevent_x { 262 int extra_data; 263 struct bufferevent bev; 264 } 265 then mem_offset should be offsetof(struct bufferevent_x, bev) 266 */ 267 off_t mem_offset; 268 269 /** Enables one or more of EV_READ|EV_WRITE on a bufferevent. Does 270 not need to adjust the 'enabled' field. Returns 0 on success, -1 271 on failure. 272 */ 273 int (*enable)(struct bufferevent *, short); 274 275 /** Disables one or more of EV_READ|EV_WRITE on a bufferevent. Does 276 not need to adjust the 'enabled' field. Returns 0 on success, -1 277 on failure. 278 */ 279 int (*disable)(struct bufferevent *, short); 280 281 /** Detatches the bufferevent from related data structures. Called as 282 * soon as its reference count reaches 0. */ 283 void (*unlink)(struct bufferevent *); 284 285 /** Free any storage and deallocate any extra data or structures used 286 in this implementation. Called when the bufferevent is 287 finalized. 288 */ 289 void (*destruct)(struct bufferevent *); 290 291 /** Called when the timeouts on the bufferevent have changed.*/ 292 int (*adj_timeouts)(struct bufferevent *); 293 294 /** Called to flush data. */ 295 int (*flush)(struct bufferevent *, short, enum bufferevent_flush_mode); 296 297 /** Called to access miscellaneous fields. */ 298 int (*ctrl)(struct bufferevent *, enum bufferevent_ctrl_op, union bufferevent_ctrl_data *); 299 300 }; 301 302 extern const struct bufferevent_ops bufferevent_ops_socket; 303 extern const struct bufferevent_ops bufferevent_ops_filter; 304 extern const struct bufferevent_ops bufferevent_ops_pair; 305 306 #define BEV_IS_SOCKET(bevp) ((bevp)->be_ops == &bufferevent_ops_socket) 307 #define BEV_IS_FILTER(bevp) ((bevp)->be_ops == &bufferevent_ops_filter) 308 #define BEV_IS_PAIR(bevp) ((bevp)->be_ops == &bufferevent_ops_pair) 309 310 #ifdef _WIN32 311 extern const struct bufferevent_ops bufferevent_ops_async; 312 #define BEV_IS_ASYNC(bevp) ((bevp)->be_ops == &bufferevent_ops_async) 313 #else 314 #define BEV_IS_ASYNC(bevp) 0 315 #endif 316 317 /** Initialize the shared parts of a bufferevent. */ 318 int bufferevent_init_common_(struct bufferevent_private *, struct event_base *, const struct bufferevent_ops *, enum bufferevent_options options); 319 320 /** For internal use: temporarily stop all reads on bufev, until the conditions 321 * in 'what' are over. */ 322 void bufferevent_suspend_read_(struct bufferevent *bufev, bufferevent_suspend_flags what); 323 /** For internal use: clear the conditions 'what' on bufev, and re-enable 324 * reading if there are no conditions left. */ 325 void bufferevent_unsuspend_read_(struct bufferevent *bufev, bufferevent_suspend_flags what); 326 327 /** For internal use: temporarily stop all writes on bufev, until the conditions 328 * in 'what' are over. */ 329 void bufferevent_suspend_write_(struct bufferevent *bufev, bufferevent_suspend_flags what); 330 /** For internal use: clear the conditions 'what' on bufev, and re-enable 331 * writing if there are no conditions left. */ 332 void bufferevent_unsuspend_write_(struct bufferevent *bufev, bufferevent_suspend_flags what); 333 334 #define bufferevent_wm_suspend_read(b) \ 335 bufferevent_suspend_read_((b), BEV_SUSPEND_WM) 336 #define bufferevent_wm_unsuspend_read(b) \ 337 bufferevent_unsuspend_read_((b), BEV_SUSPEND_WM) 338 339 /* 340 Disable a bufferevent. Equivalent to bufferevent_disable(), but 341 first resets 'connecting' flag to force EV_WRITE down for sure. 342 343 XXXX this method will go away in the future; try not to add new users. 344 See comment in evhttp_connection_reset_() for discussion. 345 346 @param bufev the bufferevent to be disabled 347 @param event any combination of EV_READ | EV_WRITE. 348 @return 0 if successful, or -1 if an error occurred 349 @see bufferevent_disable() 350 */ 351 int bufferevent_disable_hard_(struct bufferevent *bufev, short event); 352 353 /** Internal: Set up locking on a bufferevent. If lock is set, use it. 354 * Otherwise, use a new lock. */ 355 int bufferevent_enable_locking_(struct bufferevent *bufev, void *lock); 356 /** Internal: backwards compat macro for the now public function 357 * Increment the reference count on bufev. */ 358 #define bufferevent_incref_(bufev) bufferevent_incref(bufev) 359 /** Internal: Lock bufev and increase its reference count. 360 * unlocking it otherwise. */ 361 void bufferevent_incref_and_lock_(struct bufferevent *bufev); 362 /** Internal: backwards compat macro for the now public function 363 * Decrement the reference count on bufev. Returns 1 if it freed 364 * the bufferevent.*/ 365 #define bufferevent_decref_(bufev) bufferevent_decref(bufev) 366 367 /** Internal: Drop the reference count on bufev, freeing as necessary, and 368 * unlocking it otherwise. Returns 1 if it freed the bufferevent. */ 369 int bufferevent_decref_and_unlock_(struct bufferevent *bufev); 370 371 /** Internal: If callbacks are deferred and we have a read callback, schedule 372 * a readcb. Otherwise just run the readcb. Ignores watermarks. */ 373 void bufferevent_run_readcb_(struct bufferevent *bufev, int options); 374 /** Internal: If callbacks are deferred and we have a write callback, schedule 375 * a writecb. Otherwise just run the writecb. Ignores watermarks. */ 376 void bufferevent_run_writecb_(struct bufferevent *bufev, int options); 377 /** Internal: If callbacks are deferred and we have an eventcb, schedule 378 * it to run with events "what". Otherwise just run the eventcb. 379 * See bufferevent_trigger_event for meaning of "options". */ 380 void bufferevent_run_eventcb_(struct bufferevent *bufev, short what, int options); 381 382 /** Internal: Run or schedule (if deferred or options contain 383 * BEV_TRIG_DEFER_CALLBACKS) I/O callbacks specified in iotype. 384 * Must already hold the bufev lock. Honors watermarks unless 385 * BEV_TRIG_IGNORE_WATERMARKS is in options. */ 386 static inline void bufferevent_trigger_nolock_(struct bufferevent *bufev, short iotype, int options); 387 388 /* Making this inline since all of the common-case calls to this function in 389 * libevent use constant arguments. */ 390 static inline void 391 bufferevent_trigger_nolock_(struct bufferevent *bufev, short iotype, int options) 392 { 393 if ((iotype & EV_READ) && ((options & BEV_TRIG_IGNORE_WATERMARKS) || 394 evbuffer_get_length(bufev->input) >= bufev->wm_read.low)) 395 bufferevent_run_readcb_(bufev, options); 396 if ((iotype & EV_WRITE) && ((options & BEV_TRIG_IGNORE_WATERMARKS) || 397 evbuffer_get_length(bufev->output) <= bufev->wm_write.low)) 398 bufferevent_run_writecb_(bufev, options); 399 } 400 401 /** Internal: Add the event 'ev' with timeout tv, unless tv is set to 0, in 402 * which case add ev with no timeout. */ 403 int bufferevent_add_event_(struct event *ev, const struct timeval *tv); 404 405 /* ========= 406 * These next functions implement timeouts for bufferevents that aren't doing 407 * anything else with ev_read and ev_write, to handle timeouts. 408 * ========= */ 409 /** Internal use: Set up the ev_read and ev_write callbacks so that 410 * the other "generic_timeout" functions will work on it. Call this from 411 * the constructor function. */ 412 void bufferevent_init_generic_timeout_cbs_(struct bufferevent *bev); 413 /** Internal use: Add or delete the generic timeout events as appropriate. 414 * (If an event is enabled and a timeout is set, we add the event. Otherwise 415 * we delete it.) Call this from anything that changes the timeout values, 416 * that enabled EV_READ or EV_WRITE, or that disables EV_READ or EV_WRITE. */ 417 int bufferevent_generic_adj_timeouts_(struct bufferevent *bev); 418 int bufferevent_generic_adj_existing_timeouts_(struct bufferevent *bev); 419 420 enum bufferevent_options bufferevent_get_options_(struct bufferevent *bev); 421 422 const struct sockaddr* 423 bufferevent_socket_get_conn_address_(struct bufferevent *bev); 424 425 /** Internal use: We have just successfully read data into an inbuf, so 426 * reset the read timeout (if any). */ 427 #define BEV_RESET_GENERIC_READ_TIMEOUT(bev) \ 428 do { \ 429 if (evutil_timerisset(&(bev)->timeout_read)) \ 430 event_add(&(bev)->ev_read, &(bev)->timeout_read); \ 431 } while (/*CONSTCOND*/0) 432 /** Internal use: We have just successfully written data from an inbuf, so 433 * reset the read timeout (if any). */ 434 #define BEV_RESET_GENERIC_WRITE_TIMEOUT(bev) \ 435 do { \ 436 if (evutil_timerisset(&(bev)->timeout_write)) \ 437 event_add(&(bev)->ev_write, &(bev)->timeout_write); \ 438 } while (/*CONSTCOND*/0) 439 #define BEV_DEL_GENERIC_READ_TIMEOUT(bev) \ 440 event_del(&(bev)->ev_read) 441 #define BEV_DEL_GENERIC_WRITE_TIMEOUT(bev) \ 442 event_del(&(bev)->ev_write) 443 444 445 /** Internal: Given a bufferevent, return its corresponding 446 * bufferevent_private. */ 447 #define BEV_UPCAST(b) EVUTIL_UPCAST((b), struct bufferevent_private, bev) 448 449 #ifdef EVENT__DISABLE_THREAD_SUPPORT 450 #define BEV_LOCK(b) EVUTIL_NIL_STMT_ 451 #define BEV_UNLOCK(b) EVUTIL_NIL_STMT_ 452 #else 453 /** Internal: Grab the lock (if any) on a bufferevent */ 454 #define BEV_LOCK(b) do { \ 455 struct bufferevent_private *locking = BEV_UPCAST(b); \ 456 EVLOCK_LOCK(locking->lock, 0); \ 457 } while (/*CONSTCOND*/0) 458 459 /** Internal: Release the lock (if any) on a bufferevent */ 460 #define BEV_UNLOCK(b) do { \ 461 struct bufferevent_private *locking = BEV_UPCAST(b); \ 462 EVLOCK_UNLOCK(locking->lock, 0); \ 463 } while (/*CONSTCOND*/0) 464 #endif 465 466 467 /* ==== For rate-limiting. */ 468 469 int bufferevent_decrement_write_buckets_(struct bufferevent_private *bev, 470 ev_ssize_t bytes); 471 int bufferevent_decrement_read_buckets_(struct bufferevent_private *bev, 472 ev_ssize_t bytes); 473 ev_ssize_t bufferevent_get_read_max_(struct bufferevent_private *bev); 474 ev_ssize_t bufferevent_get_write_max_(struct bufferevent_private *bev); 475 476 int bufferevent_ratelim_init_(struct bufferevent_private *bev); 477 478 #ifdef __cplusplus 479 } 480 #endif 481 482 483 #endif /* BUFFEREVENT_INTERNAL_H_INCLUDED_ */ 484