1 /* 2 * Copyright (c) 2000-2004 Niels Provos <provos (at) citi.umich.edu> 3 * All rights reserved. 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 #ifdef HAVE_CONFIG_H 28 #include "config.h" 29 #endif 30 31 #ifdef WIN32 32 #define WIN32_LEAN_AND_MEAN 33 #include <winsock2.h> 34 #include <windows.h> 35 #undef WIN32_LEAN_AND_MEAN 36 #endif 37 38 #include <sys/types.h> 39 #ifndef WIN32 40 #include <sys/socket.h> 41 #endif 42 #ifdef HAVE_SYS_TIME_H 43 #include <sys/time.h> 44 #endif 45 #include <sys/queue.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #ifndef WIN32 49 #include <unistd.h> 50 #endif 51 #include <errno.h> 52 #include <signal.h> 53 #include <string.h> 54 #include <assert.h> 55 56 #include "event.h" 57 #include "evrpc.h" 58 #include "evrpc-internal.h" 59 #include "evhttp.h" 60 #include "evutil.h" 61 #include "log.h" 62 63 struct evrpc_base * 64 evrpc_init(struct evhttp *http_server) 65 { 66 struct evrpc_base* base = calloc(1, sizeof(struct evrpc_base)); 67 if (base == NULL) 68 return (NULL); 69 70 /* we rely on the tagging sub system */ 71 evtag_init(); 72 73 TAILQ_INIT(&base->registered_rpcs); 74 TAILQ_INIT(&base->input_hooks); 75 TAILQ_INIT(&base->output_hooks); 76 base->http_server = http_server; 77 78 return (base); 79 } 80 81 void 82 evrpc_free(struct evrpc_base *base) 83 { 84 struct evrpc *rpc; 85 struct evrpc_hook *hook; 86 87 while ((rpc = TAILQ_FIRST(&base->registered_rpcs)) != NULL) { 88 assert(evrpc_unregister_rpc(base, rpc->uri)); 89 } 90 while ((hook = TAILQ_FIRST(&base->input_hooks)) != NULL) { 91 assert(evrpc_remove_hook(base, EVRPC_INPUT, hook)); 92 } 93 while ((hook = TAILQ_FIRST(&base->output_hooks)) != NULL) { 94 assert(evrpc_remove_hook(base, EVRPC_OUTPUT, hook)); 95 } 96 free(base); 97 } 98 99 void * 100 evrpc_add_hook(void *vbase, 101 enum EVRPC_HOOK_TYPE hook_type, 102 int (*cb)(struct evhttp_request *, struct evbuffer *, void *), 103 void *cb_arg) 104 { 105 struct _evrpc_hooks *base = vbase; 106 struct evrpc_hook_list *head = NULL; 107 struct evrpc_hook *hook = NULL; 108 switch (hook_type) { 109 case EVRPC_INPUT: 110 head = &base->in_hooks; 111 break; 112 case EVRPC_OUTPUT: 113 head = &base->out_hooks; 114 break; 115 default: 116 assert(hook_type == EVRPC_INPUT || hook_type == EVRPC_OUTPUT); 117 } 118 119 hook = calloc(1, sizeof(struct evrpc_hook)); 120 assert(hook != NULL); 121 122 hook->process = cb; 123 hook->process_arg = cb_arg; 124 TAILQ_INSERT_TAIL(head, hook, next); 125 126 return (hook); 127 } 128 129 static int 130 evrpc_remove_hook_internal(struct evrpc_hook_list *head, void *handle) 131 { 132 struct evrpc_hook *hook = NULL; 133 TAILQ_FOREACH(hook, head, next) { 134 if (hook == handle) { 135 TAILQ_REMOVE(head, hook, next); 136 free(hook); 137 return (1); 138 } 139 } 140 141 return (0); 142 } 143 144 /* 145 * remove the hook specified by the handle 146 */ 147 148 int 149 evrpc_remove_hook(void *vbase, enum EVRPC_HOOK_TYPE hook_type, void *handle) 150 { 151 struct _evrpc_hooks *base = vbase; 152 struct evrpc_hook_list *head = NULL; 153 switch (hook_type) { 154 case EVRPC_INPUT: 155 head = &base->in_hooks; 156 break; 157 case EVRPC_OUTPUT: 158 head = &base->out_hooks; 159 break; 160 default: 161 assert(hook_type == EVRPC_INPUT || hook_type == EVRPC_OUTPUT); 162 } 163 164 return (evrpc_remove_hook_internal(head, handle)); 165 } 166 167 static int 168 evrpc_process_hooks(struct evrpc_hook_list *head, 169 struct evhttp_request *req, struct evbuffer *evbuf) 170 { 171 struct evrpc_hook *hook; 172 TAILQ_FOREACH(hook, head, next) { 173 if (hook->process(req, evbuf, hook->process_arg) == -1) 174 return (-1); 175 } 176 177 return (0); 178 } 179 180 static void evrpc_pool_schedule(struct evrpc_pool *pool); 181 static void evrpc_request_cb(struct evhttp_request *, void *); 182 void evrpc_request_done(struct evrpc_req_generic*); 183 184 /* 185 * Registers a new RPC with the HTTP server. The evrpc object is expected 186 * to have been filled in via the EVRPC_REGISTER_OBJECT macro which in turn 187 * calls this function. 188 */ 189 190 static char * 191 evrpc_construct_uri(const char *uri) 192 { 193 char *constructed_uri; 194 int constructed_uri_len; 195 196 constructed_uri_len = strlen(EVRPC_URI_PREFIX) + strlen(uri) + 1; 197 if ((constructed_uri = malloc(constructed_uri_len)) == NULL) 198 event_err(1, "%s: failed to register rpc at %s", 199 __func__, uri); 200 memcpy(constructed_uri, EVRPC_URI_PREFIX, strlen(EVRPC_URI_PREFIX)); 201 memcpy(constructed_uri + strlen(EVRPC_URI_PREFIX), uri, strlen(uri)); 202 constructed_uri[constructed_uri_len - 1] = '\0'; 203 204 return (constructed_uri); 205 } 206 207 int 208 evrpc_register_rpc(struct evrpc_base *base, struct evrpc *rpc, 209 void (*cb)(struct evrpc_req_generic *, void *), void *cb_arg) 210 { 211 char *constructed_uri = evrpc_construct_uri(rpc->uri); 212 213 rpc->base = base; 214 rpc->cb = cb; 215 rpc->cb_arg = cb_arg; 216 217 TAILQ_INSERT_TAIL(&base->registered_rpcs, rpc, next); 218 219 evhttp_set_cb(base->http_server, 220 constructed_uri, 221 evrpc_request_cb, 222 rpc); 223 224 free(constructed_uri); 225 226 return (0); 227 } 228 229 int 230 evrpc_unregister_rpc(struct evrpc_base *base, const char *name) 231 { 232 char *registered_uri = NULL; 233 struct evrpc *rpc; 234 235 /* find the right rpc; linear search might be slow */ 236 TAILQ_FOREACH(rpc, &base->registered_rpcs, next) { 237 if (strcmp(rpc->uri, name) == 0) 238 break; 239 } 240 if (rpc == NULL) { 241 /* We did not find an RPC with this name */ 242 return (-1); 243 } 244 TAILQ_REMOVE(&base->registered_rpcs, rpc, next); 245 246 free((char *)rpc->uri); 247 free(rpc); 248 249 registered_uri = evrpc_construct_uri(name); 250 251 /* remove the http server callback */ 252 assert(evhttp_del_cb(base->http_server, registered_uri) == 0); 253 254 free(registered_uri); 255 return (0); 256 } 257 258 static void 259 evrpc_request_cb(struct evhttp_request *req, void *arg) 260 { 261 struct evrpc *rpc = arg; 262 struct evrpc_req_generic *rpc_state = NULL; 263 264 /* let's verify the outside parameters */ 265 if (req->type != EVHTTP_REQ_POST || 266 EVBUFFER_LENGTH(req->input_buffer) <= 0) 267 goto error; 268 269 /* 270 * we might want to allow hooks to suspend the processing, 271 * but at the moment, we assume that they just act as simple 272 * filters. 273 */ 274 if (evrpc_process_hooks(&rpc->base->input_hooks, 275 req, req->input_buffer) == -1) 276 goto error; 277 278 rpc_state = calloc(1, sizeof(struct evrpc_req_generic)); 279 if (rpc_state == NULL) 280 goto error; 281 282 /* let's check that we can parse the request */ 283 rpc_state->request = rpc->request_new(); 284 if (rpc_state->request == NULL) 285 goto error; 286 287 rpc_state->rpc = rpc; 288 289 if (rpc->request_unmarshal( 290 rpc_state->request, req->input_buffer) == -1) { 291 /* we failed to parse the request; that's a bummer */ 292 goto error; 293 } 294 295 /* at this point, we have a well formed request, prepare the reply */ 296 297 rpc_state->reply = rpc->reply_new(); 298 if (rpc_state->reply == NULL) 299 goto error; 300 301 rpc_state->http_req = req; 302 rpc_state->done = evrpc_request_done; 303 304 /* give the rpc to the user; they can deal with it */ 305 rpc->cb(rpc_state, rpc->cb_arg); 306 307 return; 308 309 error: 310 evrpc_reqstate_free(rpc_state); 311 evhttp_send_error(req, HTTP_SERVUNAVAIL, "Service Error"); 312 return; 313 } 314 315 void 316 evrpc_reqstate_free(struct evrpc_req_generic* rpc_state) 317 { 318 /* clean up all memory */ 319 if (rpc_state != NULL) { 320 struct evrpc *rpc = rpc_state->rpc; 321 322 if (rpc_state->request != NULL) 323 rpc->request_free(rpc_state->request); 324 if (rpc_state->reply != NULL) 325 rpc->reply_free(rpc_state->reply); 326 free(rpc_state); 327 } 328 } 329 330 void 331 evrpc_request_done(struct evrpc_req_generic* rpc_state) 332 { 333 struct evhttp_request *req = rpc_state->http_req; 334 struct evrpc *rpc = rpc_state->rpc; 335 struct evbuffer* data = NULL; 336 337 if (rpc->reply_complete(rpc_state->reply) == -1) { 338 /* the reply was not completely filled in. error out */ 339 goto error; 340 } 341 342 if ((data = evbuffer_new()) == NULL) { 343 /* out of memory */ 344 goto error; 345 } 346 347 /* serialize the reply */ 348 rpc->reply_marshal(data, rpc_state->reply); 349 350 /* do hook based tweaks to the request */ 351 if (evrpc_process_hooks(&rpc->base->output_hooks, 352 req, data) == -1) 353 goto error; 354 355 /* on success, we are going to transmit marshaled binary data */ 356 if (evhttp_find_header(req->output_headers, "Content-Type") == NULL) { 357 evhttp_add_header(req->output_headers, 358 "Content-Type", "application/octet-stream"); 359 } 360 361 evhttp_send_reply(req, HTTP_OK, "OK", data); 362 363 evbuffer_free(data); 364 365 evrpc_reqstate_free(rpc_state); 366 367 return; 368 369 error: 370 if (data != NULL) 371 evbuffer_free(data); 372 evrpc_reqstate_free(rpc_state); 373 evhttp_send_error(req, HTTP_SERVUNAVAIL, "Service Error"); 374 return; 375 } 376 377 /* Client implementation of RPC site */ 378 379 static int evrpc_schedule_request(struct evhttp_connection *connection, 380 struct evrpc_request_wrapper *ctx); 381 382 struct evrpc_pool * 383 evrpc_pool_new(struct event_base *base) 384 { 385 struct evrpc_pool *pool = calloc(1, sizeof(struct evrpc_pool)); 386 if (pool == NULL) 387 return (NULL); 388 389 TAILQ_INIT(&pool->connections); 390 TAILQ_INIT(&pool->requests); 391 392 TAILQ_INIT(&pool->input_hooks); 393 TAILQ_INIT(&pool->output_hooks); 394 395 pool->base = base; 396 pool->timeout = -1; 397 398 return (pool); 399 } 400 401 static void 402 evrpc_request_wrapper_free(struct evrpc_request_wrapper *request) 403 { 404 free(request->name); 405 free(request); 406 } 407 408 void 409 evrpc_pool_free(struct evrpc_pool *pool) 410 { 411 struct evhttp_connection *connection; 412 struct evrpc_request_wrapper *request; 413 struct evrpc_hook *hook; 414 415 while ((request = TAILQ_FIRST(&pool->requests)) != NULL) { 416 TAILQ_REMOVE(&pool->requests, request, next); 417 /* if this gets more complicated we need our own function */ 418 evrpc_request_wrapper_free(request); 419 } 420 421 while ((connection = TAILQ_FIRST(&pool->connections)) != NULL) { 422 TAILQ_REMOVE(&pool->connections, connection, next); 423 evhttp_connection_free(connection); 424 } 425 426 while ((hook = TAILQ_FIRST(&pool->input_hooks)) != NULL) { 427 assert(evrpc_remove_hook(pool, EVRPC_INPUT, hook)); 428 } 429 430 while ((hook = TAILQ_FIRST(&pool->output_hooks)) != NULL) { 431 assert(evrpc_remove_hook(pool, EVRPC_OUTPUT, hook)); 432 } 433 434 free(pool); 435 } 436 437 /* 438 * Add a connection to the RPC pool. A request scheduled on the pool 439 * may use any available connection. 440 */ 441 442 void 443 evrpc_pool_add_connection(struct evrpc_pool *pool, 444 struct evhttp_connection *connection) { 445 assert(connection->http_server == NULL); 446 TAILQ_INSERT_TAIL(&pool->connections, connection, next); 447 448 /* 449 * associate an event base with this connection 450 */ 451 if (pool->base != NULL) 452 evhttp_connection_set_base(connection, pool->base); 453 454 /* 455 * unless a timeout was specifically set for a connection, 456 * the connection inherits the timeout from the pool. 457 */ 458 if (connection->timeout == -1) 459 connection->timeout = pool->timeout; 460 461 /* 462 * if we have any requests pending, schedule them with the new 463 * connections. 464 */ 465 466 if (TAILQ_FIRST(&pool->requests) != NULL) { 467 struct evrpc_request_wrapper *request = 468 TAILQ_FIRST(&pool->requests); 469 TAILQ_REMOVE(&pool->requests, request, next); 470 evrpc_schedule_request(connection, request); 471 } 472 } 473 474 void 475 evrpc_pool_set_timeout(struct evrpc_pool *pool, int timeout_in_secs) 476 { 477 struct evhttp_connection *evcon; 478 TAILQ_FOREACH(evcon, &pool->connections, next) { 479 evcon->timeout = timeout_in_secs; 480 } 481 pool->timeout = timeout_in_secs; 482 } 483 484 485 static void evrpc_reply_done(struct evhttp_request *, void *); 486 static void evrpc_request_timeout(int, short, void *); 487 488 /* 489 * Finds a connection object associated with the pool that is currently 490 * idle and can be used to make a request. 491 */ 492 static struct evhttp_connection * 493 evrpc_pool_find_connection(struct evrpc_pool *pool) 494 { 495 struct evhttp_connection *connection; 496 TAILQ_FOREACH(connection, &pool->connections, next) { 497 if (TAILQ_FIRST(&connection->requests) == NULL) 498 return (connection); 499 } 500 501 return (NULL); 502 } 503 504 /* 505 * We assume that the ctx is no longer queued on the pool. 506 */ 507 static int 508 evrpc_schedule_request(struct evhttp_connection *connection, 509 struct evrpc_request_wrapper *ctx) 510 { 511 struct evhttp_request *req = NULL; 512 struct evrpc_pool *pool = ctx->pool; 513 struct evrpc_status status; 514 char *uri = NULL; 515 int res = 0; 516 517 if ((req = evhttp_request_new(evrpc_reply_done, ctx)) == NULL) 518 goto error; 519 520 /* serialize the request data into the output buffer */ 521 ctx->request_marshal(req->output_buffer, ctx->request); 522 523 uri = evrpc_construct_uri(ctx->name); 524 if (uri == NULL) 525 goto error; 526 527 /* we need to know the connection that we might have to abort */ 528 ctx->evcon = connection; 529 530 /* apply hooks to the outgoing request */ 531 if (evrpc_process_hooks(&pool->output_hooks, 532 req, req->output_buffer) == -1) 533 goto error; 534 535 if (pool->timeout > 0) { 536 /* 537 * a timeout after which the whole rpc is going to be aborted. 538 */ 539 struct timeval tv; 540 evutil_timerclear(&tv); 541 tv.tv_sec = pool->timeout; 542 evtimer_add(&ctx->ev_timeout, &tv); 543 } 544 545 /* start the request over the connection */ 546 res = evhttp_make_request(connection, req, EVHTTP_REQ_POST, uri); 547 free(uri); 548 549 if (res == -1) 550 goto error; 551 552 return (0); 553 554 error: 555 memset(&status, 0, sizeof(status)); 556 status.error = EVRPC_STATUS_ERR_UNSTARTED; 557 (*ctx->cb)(&status, ctx->request, ctx->reply, ctx->cb_arg); 558 evrpc_request_wrapper_free(ctx); 559 return (-1); 560 } 561 562 int 563 evrpc_make_request(struct evrpc_request_wrapper *ctx) 564 { 565 struct evrpc_pool *pool = ctx->pool; 566 567 /* initialize the event structure for this rpc */ 568 evtimer_set(&ctx->ev_timeout, evrpc_request_timeout, ctx); 569 if (pool->base != NULL) 570 event_base_set(pool->base, &ctx->ev_timeout); 571 572 /* we better have some available connections on the pool */ 573 assert(TAILQ_FIRST(&pool->connections) != NULL); 574 575 /* 576 * if no connection is available, we queue the request on the pool, 577 * the next time a connection is empty, the rpc will be send on that. 578 */ 579 TAILQ_INSERT_TAIL(&pool->requests, ctx, next); 580 581 evrpc_pool_schedule(pool); 582 583 return (0); 584 } 585 586 static void 587 evrpc_reply_done(struct evhttp_request *req, void *arg) 588 { 589 struct evrpc_request_wrapper *ctx = arg; 590 struct evrpc_pool *pool = ctx->pool; 591 struct evrpc_status status; 592 int res = -1; 593 594 /* cancel any timeout we might have scheduled */ 595 event_del(&ctx->ev_timeout); 596 597 memset(&status, 0, sizeof(status)); 598 status.http_req = req; 599 600 /* we need to get the reply now */ 601 if (req != NULL) { 602 /* apply hooks to the incoming request */ 603 if (evrpc_process_hooks(&pool->input_hooks, 604 req, req->input_buffer) == -1) { 605 status.error = EVRPC_STATUS_ERR_HOOKABORTED; 606 res = -1; 607 } else { 608 res = ctx->reply_unmarshal(ctx->reply, 609 req->input_buffer); 610 if (res == -1) { 611 status.error = EVRPC_STATUS_ERR_BADPAYLOAD; 612 } 613 } 614 } else { 615 status.error = EVRPC_STATUS_ERR_TIMEOUT; 616 } 617 618 if (res == -1) { 619 /* clear everything that we might have written previously */ 620 ctx->reply_clear(ctx->reply); 621 } 622 623 (*ctx->cb)(&status, ctx->request, ctx->reply, ctx->cb_arg); 624 625 evrpc_request_wrapper_free(ctx); 626 627 /* the http layer owns the request structure */ 628 629 /* see if we can schedule another request */ 630 evrpc_pool_schedule(pool); 631 } 632 633 static void 634 evrpc_pool_schedule(struct evrpc_pool *pool) 635 { 636 struct evrpc_request_wrapper *ctx = TAILQ_FIRST(&pool->requests); 637 struct evhttp_connection *evcon; 638 639 /* if no requests are pending, we have no work */ 640 if (ctx == NULL) 641 return; 642 643 if ((evcon = evrpc_pool_find_connection(pool)) != NULL) { 644 TAILQ_REMOVE(&pool->requests, ctx, next); 645 evrpc_schedule_request(evcon, ctx); 646 } 647 } 648 649 static void 650 evrpc_request_timeout(int fd, short what, void *arg) 651 { 652 struct evrpc_request_wrapper *ctx = arg; 653 struct evhttp_connection *evcon = ctx->evcon; 654 assert(evcon != NULL); 655 656 evhttp_connection_fail(evcon, EVCON_HTTP_TIMEOUT); 657 } 658
