Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2009-2012 Niels Provos, 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 | */ |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 26 | #include "event2/event-config.h" |
| 27 | #include "evconfig-private.h" |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 28 | |
| 29 | #include <sys/types.h> |
| 30 | |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 31 | #ifdef _WIN32 |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 32 | #include <winsock2.h> |
| 33 | #endif |
| 34 | |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 35 | #include "event2/util.h" |
| 36 | #include "event2/buffer.h" |
| 37 | #include "event2/bufferevent.h" |
| 38 | #include "event2/bufferevent_struct.h" |
| 39 | #include "event2/event.h" |
| 40 | #include "defer-internal.h" |
| 41 | #include "bufferevent-internal.h" |
| 42 | #include "mm-internal.h" |
| 43 | #include "util-internal.h" |
| 44 | |
| 45 | struct bufferevent_pair { |
| 46 | struct bufferevent_private bev; |
| 47 | struct bufferevent_pair *partner; |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 48 | /* For ->destruct() lock checking */ |
| 49 | struct bufferevent_pair *unlinked_partner; |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 50 | }; |
| 51 | |
| 52 | |
| 53 | /* Given a bufferevent that's really a bev part of a bufferevent_pair, |
| 54 | * return that bufferevent_filtered. Returns NULL otherwise.*/ |
| 55 | static inline struct bufferevent_pair * |
| 56 | upcast(struct bufferevent *bev) |
| 57 | { |
| 58 | struct bufferevent_pair *bev_p; |
| 59 | if (bev->be_ops != &bufferevent_ops_pair) |
| 60 | return NULL; |
| 61 | bev_p = EVUTIL_UPCAST(bev, struct bufferevent_pair, bev.bev); |
| 62 | EVUTIL_ASSERT(bev_p->bev.bev.be_ops == &bufferevent_ops_pair); |
| 63 | return bev_p; |
| 64 | } |
| 65 | |
| 66 | #define downcast(bev_pair) (&(bev_pair)->bev.bev) |
| 67 | |
| 68 | static inline void |
| 69 | incref_and_lock(struct bufferevent *b) |
| 70 | { |
| 71 | struct bufferevent_pair *bevp; |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 72 | bufferevent_incref_and_lock_(b); |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 73 | bevp = upcast(b); |
| 74 | if (bevp->partner) |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 75 | bufferevent_incref_and_lock_(downcast(bevp->partner)); |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 76 | } |
| 77 | |
| 78 | static inline void |
| 79 | decref_and_unlock(struct bufferevent *b) |
| 80 | { |
| 81 | struct bufferevent_pair *bevp = upcast(b); |
| 82 | if (bevp->partner) |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 83 | bufferevent_decref_and_unlock_(downcast(bevp->partner)); |
| 84 | bufferevent_decref_and_unlock_(b); |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 85 | } |
| 86 | |
| 87 | /* XXX Handle close */ |
| 88 | |
| 89 | static void be_pair_outbuf_cb(struct evbuffer *, |
| 90 | const struct evbuffer_cb_info *, void *); |
| 91 | |
| 92 | static struct bufferevent_pair * |
| 93 | bufferevent_pair_elt_new(struct event_base *base, |
| 94 | int options) |
| 95 | { |
| 96 | struct bufferevent_pair *bufev; |
| 97 | if (! (bufev = mm_calloc(1, sizeof(struct bufferevent_pair)))) |
| 98 | return NULL; |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 99 | if (bufferevent_init_common_(&bufev->bev, base, &bufferevent_ops_pair, |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 100 | options)) { |
| 101 | mm_free(bufev); |
| 102 | return NULL; |
| 103 | } |
| 104 | if (!evbuffer_add_cb(bufev->bev.bev.output, be_pair_outbuf_cb, bufev)) { |
| 105 | bufferevent_free(downcast(bufev)); |
| 106 | return NULL; |
| 107 | } |
| 108 | |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 109 | bufferevent_init_generic_timeout_cbs_(&bufev->bev.bev); |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 110 | |
| 111 | return bufev; |
| 112 | } |
| 113 | |
| 114 | int |
| 115 | bufferevent_pair_new(struct event_base *base, int options, |
| 116 | struct bufferevent *pair[2]) |
| 117 | { |
| 118 | struct bufferevent_pair *bufev1 = NULL, *bufev2 = NULL; |
| 119 | int tmp_options; |
| 120 | |
| 121 | options |= BEV_OPT_DEFER_CALLBACKS; |
| 122 | tmp_options = options & ~BEV_OPT_THREADSAFE; |
| 123 | |
| 124 | bufev1 = bufferevent_pair_elt_new(base, options); |
| 125 | if (!bufev1) |
| 126 | return -1; |
| 127 | bufev2 = bufferevent_pair_elt_new(base, tmp_options); |
| 128 | if (!bufev2) { |
| 129 | bufferevent_free(downcast(bufev1)); |
| 130 | return -1; |
| 131 | } |
| 132 | |
| 133 | if (options & BEV_OPT_THREADSAFE) { |
| 134 | /*XXXX check return */ |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 135 | bufferevent_enable_locking_(downcast(bufev2), bufev1->bev.lock); |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 136 | } |
| 137 | |
| 138 | bufev1->partner = bufev2; |
| 139 | bufev2->partner = bufev1; |
| 140 | |
| 141 | evbuffer_freeze(downcast(bufev1)->input, 0); |
| 142 | evbuffer_freeze(downcast(bufev1)->output, 1); |
| 143 | evbuffer_freeze(downcast(bufev2)->input, 0); |
| 144 | evbuffer_freeze(downcast(bufev2)->output, 1); |
| 145 | |
| 146 | pair[0] = downcast(bufev1); |
| 147 | pair[1] = downcast(bufev2); |
| 148 | |
| 149 | return 0; |
| 150 | } |
| 151 | |
| 152 | static void |
| 153 | be_pair_transfer(struct bufferevent *src, struct bufferevent *dst, |
| 154 | int ignore_wm) |
| 155 | { |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 156 | size_t dst_size; |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 157 | size_t n; |
| 158 | |
| 159 | evbuffer_unfreeze(src->output, 1); |
| 160 | evbuffer_unfreeze(dst->input, 0); |
| 161 | |
| 162 | if (dst->wm_read.high) { |
| 163 | dst_size = evbuffer_get_length(dst->input); |
| 164 | if (dst_size < dst->wm_read.high) { |
| 165 | n = dst->wm_read.high - dst_size; |
| 166 | evbuffer_remove_buffer(src->output, dst->input, n); |
| 167 | } else { |
| 168 | if (!ignore_wm) |
| 169 | goto done; |
| 170 | n = evbuffer_get_length(src->output); |
| 171 | evbuffer_add_buffer(dst->input, src->output); |
| 172 | } |
| 173 | } else { |
| 174 | n = evbuffer_get_length(src->output); |
| 175 | evbuffer_add_buffer(dst->input, src->output); |
| 176 | } |
| 177 | |
| 178 | if (n) { |
| 179 | BEV_RESET_GENERIC_READ_TIMEOUT(dst); |
| 180 | |
| 181 | if (evbuffer_get_length(dst->output)) |
| 182 | BEV_RESET_GENERIC_WRITE_TIMEOUT(dst); |
| 183 | else |
| 184 | BEV_DEL_GENERIC_WRITE_TIMEOUT(dst); |
| 185 | } |
| 186 | |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 187 | bufferevent_trigger_nolock_(dst, EV_READ, 0); |
| 188 | bufferevent_trigger_nolock_(src, EV_WRITE, 0); |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 189 | done: |
| 190 | evbuffer_freeze(src->output, 1); |
| 191 | evbuffer_freeze(dst->input, 0); |
| 192 | } |
| 193 | |
| 194 | static inline int |
| 195 | be_pair_wants_to_talk(struct bufferevent_pair *src, |
| 196 | struct bufferevent_pair *dst) |
| 197 | { |
| 198 | return (downcast(src)->enabled & EV_WRITE) && |
| 199 | (downcast(dst)->enabled & EV_READ) && |
| 200 | !dst->bev.read_suspended && |
| 201 | evbuffer_get_length(downcast(src)->output); |
| 202 | } |
| 203 | |
| 204 | static void |
| 205 | be_pair_outbuf_cb(struct evbuffer *outbuf, |
| 206 | const struct evbuffer_cb_info *info, void *arg) |
| 207 | { |
| 208 | struct bufferevent_pair *bev_pair = arg; |
| 209 | struct bufferevent_pair *partner = bev_pair->partner; |
| 210 | |
| 211 | incref_and_lock(downcast(bev_pair)); |
| 212 | |
| 213 | if (info->n_added > info->n_deleted && partner) { |
| 214 | /* We got more data. If the other side's reading, then |
| 215 | hand it over. */ |
| 216 | if (be_pair_wants_to_talk(bev_pair, partner)) { |
| 217 | be_pair_transfer(downcast(bev_pair), downcast(partner), 0); |
| 218 | } |
| 219 | } |
| 220 | |
| 221 | decref_and_unlock(downcast(bev_pair)); |
| 222 | } |
| 223 | |
| 224 | static int |
| 225 | be_pair_enable(struct bufferevent *bufev, short events) |
| 226 | { |
| 227 | struct bufferevent_pair *bev_p = upcast(bufev); |
| 228 | struct bufferevent_pair *partner = bev_p->partner; |
| 229 | |
| 230 | incref_and_lock(bufev); |
| 231 | |
| 232 | if (events & EV_READ) { |
| 233 | BEV_RESET_GENERIC_READ_TIMEOUT(bufev); |
| 234 | } |
| 235 | if ((events & EV_WRITE) && evbuffer_get_length(bufev->output)) |
| 236 | BEV_RESET_GENERIC_WRITE_TIMEOUT(bufev); |
| 237 | |
| 238 | /* We're starting to read! Does the other side have anything to write?*/ |
| 239 | if ((events & EV_READ) && partner && |
| 240 | be_pair_wants_to_talk(partner, bev_p)) { |
| 241 | be_pair_transfer(downcast(partner), bufev, 0); |
| 242 | } |
| 243 | /* We're starting to write! Does the other side want to read? */ |
| 244 | if ((events & EV_WRITE) && partner && |
| 245 | be_pair_wants_to_talk(bev_p, partner)) { |
| 246 | be_pair_transfer(bufev, downcast(partner), 0); |
| 247 | } |
| 248 | decref_and_unlock(bufev); |
| 249 | return 0; |
| 250 | } |
| 251 | |
| 252 | static int |
| 253 | be_pair_disable(struct bufferevent *bev, short events) |
| 254 | { |
| 255 | if (events & EV_READ) { |
| 256 | BEV_DEL_GENERIC_READ_TIMEOUT(bev); |
| 257 | } |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 258 | if (events & EV_WRITE) { |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 259 | BEV_DEL_GENERIC_WRITE_TIMEOUT(bev); |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 260 | } |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 261 | return 0; |
| 262 | } |
| 263 | |
| 264 | static void |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 265 | be_pair_unlink(struct bufferevent *bev) |
| 266 | { |
| 267 | struct bufferevent_pair *bev_p = upcast(bev); |
| 268 | |
| 269 | if (bev_p->partner) { |
| 270 | bev_p->unlinked_partner = bev_p->partner; |
| 271 | bev_p->partner->partner = NULL; |
| 272 | bev_p->partner = NULL; |
| 273 | } |
| 274 | } |
| 275 | |
| 276 | /* Free *shared* lock in the latest be (since we share it between two of them). */ |
| 277 | static void |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 278 | be_pair_destruct(struct bufferevent *bev) |
| 279 | { |
| 280 | struct bufferevent_pair *bev_p = upcast(bev); |
| 281 | |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 282 | /* Transfer ownership of the lock into partner, otherwise we will use |
| 283 | * already free'd lock during freeing second bev, see next example: |
| 284 | * |
| 285 | * bev1->own_lock = 1 |
| 286 | * bev2->own_lock = 0 |
| 287 | * bev2->lock = bev1->lock |
| 288 | * |
| 289 | * bufferevent_free(bev1) # refcnt == 0 -> unlink |
| 290 | * bufferevent_free(bev2) # refcnt == 0 -> unlink |
| 291 | * |
| 292 | * event_base_free() -> finilizers -> EVTHREAD_FREE_LOCK(bev1->lock) |
| 293 | * -> BEV_LOCK(bev2->lock) <-- already freed |
| 294 | * |
| 295 | * Where bev1 == pair[0], bev2 == pair[1]. |
| 296 | */ |
| 297 | if (bev_p->unlinked_partner && bev_p->bev.own_lock) { |
| 298 | bev_p->unlinked_partner->bev.own_lock = 1; |
| 299 | bev_p->bev.own_lock = 0; |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 300 | } |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 301 | bev_p->unlinked_partner = NULL; |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 302 | } |
| 303 | |
| 304 | static int |
| 305 | be_pair_flush(struct bufferevent *bev, short iotype, |
| 306 | enum bufferevent_flush_mode mode) |
| 307 | { |
| 308 | struct bufferevent_pair *bev_p = upcast(bev); |
| 309 | struct bufferevent *partner; |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 310 | |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 311 | if (!bev_p->partner) |
| 312 | return -1; |
| 313 | |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 314 | if (mode == BEV_NORMAL) |
| 315 | return 0; |
| 316 | |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 317 | incref_and_lock(bev); |
| 318 | |
| 319 | partner = downcast(bev_p->partner); |
| 320 | |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 321 | if ((iotype & EV_READ) != 0) |
| 322 | be_pair_transfer(partner, bev, 1); |
| 323 | |
| 324 | if ((iotype & EV_WRITE) != 0) |
| 325 | be_pair_transfer(bev, partner, 1); |
| 326 | |
| 327 | if (mode == BEV_FINISHED) { |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 328 | short what = BEV_EVENT_EOF; |
| 329 | if (iotype & EV_READ) |
| 330 | what |= BEV_EVENT_WRITING; |
| 331 | if (iotype & EV_WRITE) |
| 332 | what |= BEV_EVENT_READING; |
| 333 | bufferevent_run_eventcb_(partner, what, 0); |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 334 | } |
| 335 | decref_and_unlock(bev); |
| 336 | return 0; |
| 337 | } |
| 338 | |
| 339 | struct bufferevent * |
| 340 | bufferevent_pair_get_partner(struct bufferevent *bev) |
| 341 | { |
| 342 | struct bufferevent_pair *bev_p; |
| 343 | struct bufferevent *partner = NULL; |
| 344 | bev_p = upcast(bev); |
| 345 | if (! bev_p) |
| 346 | return NULL; |
| 347 | |
| 348 | incref_and_lock(bev); |
| 349 | if (bev_p->partner) |
| 350 | partner = downcast(bev_p->partner); |
| 351 | decref_and_unlock(bev); |
| 352 | return partner; |
| 353 | } |
| 354 | |
| 355 | const struct bufferevent_ops bufferevent_ops_pair = { |
| 356 | "pair_elt", |
| 357 | evutil_offsetof(struct bufferevent_pair, bev.bev), |
| 358 | be_pair_enable, |
| 359 | be_pair_disable, |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 360 | be_pair_unlink, |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 361 | be_pair_destruct, |
Narayan Kamath | fc74cb4 | 2017-09-13 12:53:52 +0100 | [diff] [blame] | 362 | bufferevent_generic_adj_timeouts_, |
Christopher Wiley | e867981 | 2015-07-01 13:36:18 -0700 | [diff] [blame] | 363 | be_pair_flush, |
| 364 | NULL, /* ctrl */ |
| 365 | }; |