release/src/router/nginx/src/http/modules/ngx_http_limit_req_module.c

   1
   2 /*
   3  * Copyright (C) Igor Sysoev
   4  * Copyright (C) Nginx, Inc.
   5  */
   6
   7
   8 #include <ngx_config.h>
   9 #include <ngx_core.h>
  10 #include <ngx_http.h>
  11
  12
  13 typedef struct {
  14     u_char                       color;
  15     u_char                       dummy;
  16     u_short                      len;
  17     ngx_queue_t                  queue;
  18     ngx_msec_t                   last;
  19     /* integer value, 1 corresponds to 0.001 r/s */
  20     ngx_uint_t                   excess;
  21     ngx_uint_t                   count;
  22     u_char                       data[1];
  23 } ngx_http_limit_req_node_t;
  24
  25
  26 typedef struct {
  27     ngx_rbtree_t                  rbtree;
  28     ngx_rbtree_node_t             sentinel;
  29     ngx_queue_t                   queue;
  30 } ngx_http_limit_req_shctx_t;
  31
  32
  33 typedef struct {
  34     ngx_http_limit_req_shctx_t  *sh;
  35     ngx_slab_pool_t             *shpool;
  36     /* integer value, 1 corresponds to 0.001 r/s */
  37     ngx_uint_t                   rate;
  38     ngx_int_t                    index;
  39     ngx_str_t                    var;
  40     ngx_http_limit_req_node_t   *node;
  41 } ngx_http_limit_req_ctx_t;
  42
  43
  44 typedef struct {
  45     ngx_shm_zone_t              *shm_zone;
  46     /* integer value, 1 corresponds to 0.001 r/s */
  47     ngx_uint_t                   burst;
  48     ngx_uint_t                   nodelay; /* unsigned  nodelay:1 */
  49 } ngx_http_limit_req_limit_t;
  50
  51
  52 typedef struct {
  53     ngx_array_t                  limits;
  54     ngx_uint_t                   limit_log_level;
  55     ngx_uint_t                   delay_log_level;
  56     ngx_uint_t                   status_code;
  57 } ngx_http_limit_req_conf_t;
  58
  59
  60 static void ngx_http_limit_req_delay(ngx_http_request_t *r);
  61 static ngx_int_t ngx_http_limit_req_lookup(ngx_http_limit_req_limit_t *limit,
  62     ngx_uint_t hash, u_char *data, size_t len, ngx_uint_t *ep,
  63     ngx_uint_t account);
  64 static ngx_msec_t ngx_http_limit_req_account(ngx_http_limit_req_limit_t *limits,
  65     ngx_uint_t n, ngx_uint_t *ep, ngx_http_limit_req_limit_t **limit);
  66 static void ngx_http_limit_req_expire(ngx_http_limit_req_ctx_t *ctx,
  67     ngx_uint_t n);
  68
  69 static void *ngx_http_limit_req_create_conf(ngx_conf_t *cf);
  70 static char *ngx_http_limit_req_merge_conf(ngx_conf_t *cf, void *parent,
  71     void *child);
  72 static char *ngx_http_limit_req_zone(ngx_conf_t *cf, ngx_command_t *cmd,
  73     void *conf);
  74 static char *ngx_http_limit_req(ngx_conf_t *cf, ngx_command_t *cmd,
  75     void *conf);
  76 static ngx_int_t ngx_http_limit_req_init(ngx_conf_t *cf);
  77
  78
  79 static ngx_conf_enum_t  ngx_http_limit_req_log_levels[] = {
  80     { ngx_string("info"), NGX_LOG_INFO },
  81     { ngx_string("notice"), NGX_LOG_NOTICE },
  82     { ngx_string("warn"), NGX_LOG_WARN },
  83     { ngx_string("error"), NGX_LOG_ERR },
  84     { ngx_null_string, 0 }
  85 };
  86
  87
  88 static ngx_conf_num_bounds_t  ngx_http_limit_req_status_bounds = {
  89     ngx_conf_check_num_bounds, 400, 599
  90 };
  91
  92
  93 static ngx_command_t  ngx_http_limit_req_commands[] = {
  94
  95     { ngx_string("limit_req_zone"),
  96       NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE3,
  97       ngx_http_limit_req_zone,
  98       0,
  99       0,
 100       NULL },
 101
 102     { ngx_string("limit_req"),
 103       NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE123,
 104       ngx_http_limit_req,
 105       NGX_HTTP_LOC_CONF_OFFSET,
 106       0,
 107       NULL },
 108
 109     { ngx_string("limit_req_log_level"),
 110       NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
 111       ngx_conf_set_enum_slot,
 112       NGX_HTTP_LOC_CONF_OFFSET,
 113       offsetof(ngx_http_limit_req_conf_t, limit_log_level),
 114       &ngx_http_limit_req_log_levels },
 115
 116     { ngx_string("limit_req_status"),
 117       NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
 118       ngx_conf_set_num_slot,
 119       NGX_HTTP_LOC_CONF_OFFSET,
 120       offsetof(ngx_http_limit_req_conf_t, status_code),
 121       &ngx_http_limit_req_status_bounds },
 122
 123       ngx_null_command
 124 };
 125
 126
 127 static ngx_http_module_t  ngx_http_limit_req_module_ctx = {
 128     NULL,                                  /* preconfiguration */
 129     ngx_http_limit_req_init,               /* postconfiguration */
 130
 131     NULL,                                  /* create main configuration */
 132     NULL,                                  /* init main configuration */
 133
 134     NULL,                                  /* create server configuration */
 135     NULL,                                  /* merge server configuration */
 136
 137     ngx_http_limit_req_create_conf,        /* create location configuration */
 138     ngx_http_limit_req_merge_conf          /* merge location configuration */
 139 };
 140
 141
 142 ngx_module_t  ngx_http_limit_req_module = {
 143     NGX_MODULE_V1,
 144     &ngx_http_limit_req_module_ctx,        /* module context */
 145     ngx_http_limit_req_commands,           /* module directives */
 146     NGX_HTTP_MODULE,                       /* module type */
 147     NULL,                                  /* init master */
 148     NULL,                                  /* init module */
 149     NULL,                                  /* init process */
 150     NULL,                                  /* init thread */
 151     NULL,                                  /* exit thread */
 152     NULL,                                  /* exit process */
 153     NULL,                                  /* exit master */
 154     NGX_MODULE_V1_PADDING
 155 };
 156
 157
 158 static ngx_int_t
 159 ngx_http_limit_req_handler(ngx_http_request_t *r)
 160 {
 161     size_t                       len;
 162     uint32_t                     hash;
 163     ngx_int_t                    rc;
 164     ngx_uint_t                   n, excess;
 165     ngx_msec_t                   delay;
 166     ngx_http_variable_value_t   *vv;
 167     ngx_http_limit_req_ctx_t    *ctx;
 168     ngx_http_limit_req_conf_t   *lrcf;
 169     ngx_http_limit_req_limit_t  *limit, *limits;
 170
 171     if (r->main->limit_req_set) {
 172         return NGX_DECLINED;
 173     }
 174
 175     lrcf = ngx_http_get_module_loc_conf(r, ngx_http_limit_req_module);
 176     limits = lrcf->limits.elts;
 177
 178     excess = 0;
 179
 180     rc = NGX_DECLINED;
 181
 182 #if (NGX_SUPPRESS_WARN)
 183     limit = NULL;
 184 #endif
 185
 186     for (n = 0; n < lrcf->limits.nelts; n++) {
 187
 188         limit = &limits[n];
 189
 190         ctx = limit->shm_zone->data;
 191
 192         vv = ngx_http_get_indexed_variable(r, ctx->index);
 193
 194         if (vv == NULL || vv->not_found) {
 195             continue;
 196         }
 197
 198         len = vv->len;
 199
 200         if (len == 0) {
 201             continue;
 202         }
 203
 204         if (len > 65535) {
 205             ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
 206                           "the value of the \"%V\" variable "
 207                           "is more than 65535 bytes: \"%v\"",
 208                           &ctx->var, vv);
 209             continue;
 210         }
 211
 212         hash = ngx_crc32_short(vv->data, len);
 213
 214         ngx_shmtx_lock(&ctx->shpool->mutex);
 215
 216         rc = ngx_http_limit_req_lookup(limit, hash, vv->data, len, &excess,
 217                                        (n == lrcf->limits.nelts - 1));
 218
 219         ngx_shmtx_unlock(&ctx->shpool->mutex);
 220
 221         ngx_log_debug4(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
 222                        "limit_req[%ui]: %i %ui.%03ui",
 223                        n, rc, excess / 1000, excess % 1000);
 224
 225         if (rc != NGX_AGAIN) {
 226             break;
 227         }
 228     }
 229
 230     if (rc == NGX_DECLINED) {
 231         return NGX_DECLINED;
 232     }
 233
 234     r->main->limit_req_set = 1;
 235
 236     if (rc == NGX_BUSY || rc == NGX_ERROR) {
 237
 238         if (rc == NGX_BUSY) {
 239             ngx_log_error(lrcf->limit_log_level, r->connection->log, 0,
 240                           "limiting requests, excess: %ui.%03ui by zone \"%V\"",
 241                           excess / 1000, excess % 1000,
 242                           &limit->shm_zone->shm.name);
 243         }
 244
 245         while (n--) {
 246             ctx = limits[n].shm_zone->data;
 247
 248             if (ctx->node == NULL) {
 249                 continue;
 250             }
 251
 252             ngx_shmtx_lock(&ctx->shpool->mutex);
 253
 254             ctx->node->count--;
 255
 256             ngx_shmtx_unlock(&ctx->shpool->mutex);
 257
 258             ctx->node = NULL;
 259         }
 260
 261         return lrcf->status_code;
 262     }
 263
 264     /* rc == NGX_AGAIN || rc == NGX_OK */
 265
 266     if (rc == NGX_AGAIN) {
 267         excess = 0;
 268     }
 269
 270     delay = ngx_http_limit_req_account(limits, n, &excess, &limit);
 271
 272     if (!delay) {
 273         return NGX_DECLINED;
 274     }
 275
 276     ngx_log_error(lrcf->delay_log_level, r->connection->log, 0,
 277                   "delaying request, excess: %ui.%03ui, by zone \"%V\"",
 278                   excess / 1000, excess % 1000, &limit->shm_zone->shm.name);
 279
 280     if (ngx_handle_read_event(r->connection->read, 0) != NGX_OK) {
 281         return NGX_HTTP_INTERNAL_SERVER_ERROR;
 282     }
 283
 284     r->read_event_handler = ngx_http_test_reading;
 285     r->write_event_handler = ngx_http_limit_req_delay;
 286     ngx_add_timer(r->connection->write, delay);
 287
 288     return NGX_AGAIN;
 289 }
 290
 291
 292 static void
 293 ngx_http_limit_req_delay(ngx_http_request_t *r)
 294 {
 295     ngx_event_t  *wev;
 296
 297     ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
 298                    "limit_req delay");
 299
 300     wev = r->connection->write;
 301
 302     if (!wev->timedout) {
 303
 304         if (ngx_handle_write_event(wev, 0) != NGX_OK) {
 305             ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
 306         }
 307
 308         return;
 309     }
 310
 311     wev->timedout = 0;
 312
 313     if (ngx_handle_read_event(r->connection->read, 0) != NGX_OK) {
 314         ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
 315         return;
 316     }
 317
 318     r->read_event_handler = ngx_http_block_reading;
 319     r->write_event_handler = ngx_http_core_run_phases;
 320
 321     ngx_http_core_run_phases(r);
 322 }
 323
 324
 325 static void
 326 ngx_http_limit_req_rbtree_insert_value(ngx_rbtree_node_t *temp,
 327     ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel)
 328 {
 329     ngx_rbtree_node_t          **p;
 330     ngx_http_limit_req_node_t   *lrn, *lrnt;
 331
 332     for ( ;; ) {
 333
 334         if (node->key < temp->key) {
 335
 336             p = &temp->left;
 337
 338         } else if (node->key > temp->key) {
 339
 340             p = &temp->right;
 341
 342         } else { /* node->key == temp->key */
 343
 344             lrn = (ngx_http_limit_req_node_t *) &node->color;
 345             lrnt = (ngx_http_limit_req_node_t *) &temp->color;
 346
 347             p = (ngx_memn2cmp(lrn->data, lrnt->data, lrn->len, lrnt->len) < 0)
 348                 ? &temp->left : &temp->right;
 349         }
 350
 351         if (*p == sentinel) {
 352             break;
 353         }
 354
 355         temp = *p;
 356     }
 357
 358     *p = node;
 359     node->parent = temp;
 360     node->left = sentinel;
 361     node->right = sentinel;
 362     ngx_rbt_red(node);
 363 }
 364
 365
 366 static ngx_int_t
 367 ngx_http_limit_req_lookup(ngx_http_limit_req_limit_t *limit, ngx_uint_t hash,
 368     u_char *data, size_t len, ngx_uint_t *ep, ngx_uint_t account)
 369 {
 370     size_t                      size;
 371     ngx_int_t                   rc, excess;
 372     ngx_time_t                 *tp;
 373     ngx_msec_t                  now;
 374     ngx_msec_int_t              ms;
 375     ngx_rbtree_node_t          *node, *sentinel;
 376     ngx_http_limit_req_ctx_t   *ctx;
 377     ngx_http_limit_req_node_t  *lr;
 378
 379     tp = ngx_timeofday();
 380     now = (ngx_msec_t) (tp->sec * 1000 + tp->msec);
 381
 382     ctx = limit->shm_zone->data;
 383
 384     node = ctx->sh->rbtree.root;
 385     sentinel = ctx->sh->rbtree.sentinel;
 386
 387     while (node != sentinel) {
 388
 389         if (hash < node->key) {
 390             node = node->left;
 391             continue;
 392         }
 393
 394         if (hash > node->key) {
 395             node = node->right;
 396             continue;
 397         }
 398
 399         /* hash == node->key */
 400
 401         lr = (ngx_http_limit_req_node_t *) &node->color;
 402
 403         rc = ngx_memn2cmp(data, lr->data, len, (size_t) lr->len);
 404
 405         if (rc == 0) {
 406             ngx_queue_remove(&lr->queue);
 407             ngx_queue_insert_head(&ctx->sh->queue, &lr->queue);
 408
 409             ms = (ngx_msec_int_t) (now - lr->last);
 410
 411             excess = lr->excess - ctx->rate * ngx_abs(ms) / 1000 + 1000;
 412
 413             if (excess < 0) {
 414                 excess = 0;
 415             }
 416
 417             *ep = excess;
 418
 419             if ((ngx_uint_t) excess > limit->burst) {
 420                 return NGX_BUSY;
 421             }
 422
 423             if (account) {
 424                 lr->excess = excess;
 425                 lr->last = now;
 426                 return NGX_OK;
 427             }
 428
 429             lr->count++;
 430
 431             ctx->node = lr;
 432
 433             return NGX_AGAIN;
 434         }
 435
 436         node = (rc < 0) ? node->left : node->right;
 437     }
 438
 439     *ep = 0;
 440
 441     size = offsetof(ngx_rbtree_node_t, color)
 442            + offsetof(ngx_http_limit_req_node_t, data)
 443            + len;
 444
 445     ngx_http_limit_req_expire(ctx, 1);
 446
 447     node = ngx_slab_alloc_locked(ctx->shpool, size);
 448
 449     if (node == NULL) {
 450         ngx_http_limit_req_expire(ctx, 0);
 451
 452         node = ngx_slab_alloc_locked(ctx->shpool, size);
 453         if (node == NULL) {
 454             return NGX_ERROR;
 455         }
 456     }
 457
 458     node->key = hash;
 459
 460     lr = (ngx_http_limit_req_node_t *) &node->color;
 461
 462     lr->len = (u_char) len;
 463     lr->excess = 0;
 464
 465     ngx_memcpy(lr->data, data, len);
 466
 467     ngx_rbtree_insert(&ctx->sh->rbtree, node);
 468
 469     ngx_queue_insert_head(&ctx->sh->queue, &lr->queue);
 470
 471     if (account) {
 472         lr->last = now;
 473         lr->count = 0;
 474         return NGX_OK;
 475     }
 476
 477     lr->last = 0;
 478     lr->count = 1;
 479
 480     ctx->node = lr;
 481
 482     return NGX_AGAIN;
 483 }
 484
 485
 486 static ngx_msec_t
 487 ngx_http_limit_req_account(ngx_http_limit_req_limit_t *limits, ngx_uint_t n,
 488     ngx_uint_t *ep, ngx_http_limit_req_limit_t **limit)
 489 {
 490     ngx_int_t                   excess;
 491     ngx_time_t                 *tp;
 492     ngx_msec_t                  now, delay, max_delay;
 493     ngx_msec_int_t              ms;
 494     ngx_http_limit_req_ctx_t   *ctx;
 495     ngx_http_limit_req_node_t  *lr;
 496
 497     excess = *ep;
 498
 499     if (excess == 0 || (*limit)->nodelay) {
 500         max_delay = 0;
 501
 502     } else {
 503         ctx = (*limit)->shm_zone->data;
 504         max_delay = excess * 1000 / ctx->rate;
 505     }
 506
 507     while (n--) {
 508         ctx = limits[n].shm_zone->data;
 509         lr = ctx->node;
 510
 511         if (lr == NULL) {
 512             continue;
 513         }
 514
 515         ngx_shmtx_lock(&ctx->shpool->mutex);
 516
 517         tp = ngx_timeofday();
 518
 519         now = (ngx_msec_t) (tp->sec * 1000 + tp->msec);
 520         ms = (ngx_msec_int_t) (now - lr->last);
 521
 522         excess = lr->excess - ctx->rate * ngx_abs(ms) / 1000 + 1000;
 523
 524         if (excess < 0) {
 525             excess = 0;
 526         }
 527
 528         lr->last = now;
 529         lr->excess = excess;
 530         lr->count--;
 531
 532         ngx_shmtx_unlock(&ctx->shpool->mutex);
 533
 534         ctx->node = NULL;
 535
 536         if (limits[n].nodelay) {
 537             continue;
 538         }
 539
 540         delay = excess * 1000 / ctx->rate;
 541
 542         if (delay > max_delay) {
 543             max_delay = delay;
 544             *ep = excess;
 545             *limit = &limits[n];
 546         }
 547     }
 548
 549     return max_delay;
 550 }
 551
 552
 553 static void
 554 ngx_http_limit_req_expire(ngx_http_limit_req_ctx_t *ctx, ngx_uint_t n)
 555 {
 556     ngx_int_t                   excess;
 557     ngx_time_t                 *tp;
 558     ngx_msec_t                  now;
 559     ngx_queue_t                *q;
 560     ngx_msec_int_t              ms;
 561     ngx_rbtree_node_t          *node;
 562     ngx_http_limit_req_node_t  *lr;
 563
 564     tp = ngx_timeofday();
 565
 566     now = (ngx_msec_t) (tp->sec * 1000 + tp->msec);
 567
 568     /*
 569      * n == 1 deletes one or two zero rate entries
 570      * n == 0 deletes oldest entry by force
 571      *        and one or two zero rate entries
 572      */
 573
 574     while (n < 3) {
 575
 576         if (ngx_queue_empty(&ctx->sh->queue)) {
 577             return;
 578         }
 579
 580         q = ngx_queue_last(&ctx->sh->queue);
 581
 582         lr = ngx_queue_data(q, ngx_http_limit_req_node_t, queue);
 583
 584         if (lr->count) {
 585
 586             /*
 587              * There is not much sense in looking further,
 588              * because we bump nodes on the lookup stage.
 589              */
 590
 591             return;
 592         }
 593
 594         if (n++ != 0) {
 595
 596             ms = (ngx_msec_int_t) (now - lr->last);
 597             ms = ngx_abs(ms);
 598
 599             if (ms < 60000) {
 600                 return;
 601             }
 602
 603             excess = lr->excess - ctx->rate * ms / 1000;
 604
 605             if (excess > 0) {
 606                 return;
 607             }
 608         }
 609
 610         ngx_queue_remove(q);
 611
 612         node = (ngx_rbtree_node_t *)
 613                    ((u_char *) lr - offsetof(ngx_rbtree_node_t, color));
 614
 615         ngx_rbtree_delete(&ctx->sh->rbtree, node);
 616
 617         ngx_slab_free_locked(ctx->shpool, node);
 618     }
 619 }
 620
 621
 622 static ngx_int_t
 623 ngx_http_limit_req_init_zone(ngx_shm_zone_t *shm_zone, void *data)
 624 {
 625     ngx_http_limit_req_ctx_t  *octx = data;
 626
 627     size_t                     len;
 628     ngx_http_limit_req_ctx_t  *ctx;
 629
 630     ctx = shm_zone->data;
 631
 632     if (octx) {
 633         if (ngx_strcmp(ctx->var.data, octx->var.data) != 0) {
 634             ngx_log_error(NGX_LOG_EMERG, shm_zone->shm.log, 0,
 635                           "limit_req \"%V\" uses the \"%V\" variable "
 636                           "while previously it used the \"%V\" variable",
 637                           &shm_zone->shm.name, &ctx->var, &octx->var);
 638             return NGX_ERROR;
 639         }
 640
 641         ctx->sh = octx->sh;
 642         ctx->shpool = octx->shpool;
 643
 644         return NGX_OK;
 645     }
 646
 647     ctx->shpool = (ngx_slab_pool_t *) shm_zone->shm.addr;
 648
 649     if (shm_zone->shm.exists) {
 650         ctx->sh = ctx->shpool->data;
 651
 652         return NGX_OK;
 653     }
 654
 655     ctx->sh = ngx_slab_alloc(ctx->shpool, sizeof(ngx_http_limit_req_shctx_t));
 656     if (ctx->sh == NULL) {
 657         return NGX_ERROR;
 658     }
 659
 660     ctx->shpool->data = ctx->sh;
 661
 662     ngx_rbtree_init(&ctx->sh->rbtree, &ctx->sh->sentinel,
 663                     ngx_http_limit_req_rbtree_insert_value);
 664
 665     ngx_queue_init(&ctx->sh->queue);
 666
 667     len = sizeof(" in limit_req zone \"\"") + shm_zone->shm.name.len;
 668
 669     ctx->shpool->log_ctx = ngx_slab_alloc(ctx->shpool, len);
 670     if (ctx->shpool->log_ctx == NULL) {
 671         return NGX_ERROR;
 672     }
 673
 674     ngx_sprintf(ctx->shpool->log_ctx, " in limit_req zone \"%V\"%Z",
 675                 &shm_zone->shm.name);
 676
 677     return NGX_OK;
 678 }
 679
 680
 681 static void *
 682 ngx_http_limit_req_create_conf(ngx_conf_t *cf)
 683 {
 684     ngx_http_limit_req_conf_t  *conf;
 685
 686     conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_req_conf_t));
 687     if (conf == NULL) {
 688         return NULL;
 689     }
 690
 691     /*
 692      * set by ngx_pcalloc():
 693      *
 694      *     conf->limits.elts = NULL;
 695      */
 696
 697     conf->limit_log_level = NGX_CONF_UNSET_UINT;
 698     conf->status_code = NGX_CONF_UNSET_UINT;
 699
 700     return conf;
 701 }
 702
 703
 704 static char *
 705 ngx_http_limit_req_merge_conf(ngx_conf_t *cf, void *parent, void *child)
 706 {
 707     ngx_http_limit_req_conf_t *prev = parent;
 708     ngx_http_limit_req_conf_t *conf = child;
 709
 710     if (conf->limits.elts == NULL) {
 711         conf->limits = prev->limits;
 712     }
 713
 714     ngx_conf_merge_uint_value(conf->limit_log_level, prev->limit_log_level,
 715                               NGX_LOG_ERR);
 716
 717     conf->delay_log_level = (conf->limit_log_level == NGX_LOG_INFO) ?
 718                                 NGX_LOG_INFO : conf->limit_log_level + 1;
 719
 720     ngx_conf_merge_uint_value(conf->status_code, prev->status_code,
 721                               NGX_HTTP_SERVICE_UNAVAILABLE);
 722
 723     return NGX_CONF_OK;
 724 }
 725
 726
 727 static char *
 728 ngx_http_limit_req_zone(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
 729 {
 730     u_char                    *p;
 731     size_t                     len;
 732     ssize_t                    size;
 733     ngx_str_t                 *value, name, s;
 734     ngx_int_t                  rate, scale;
 735     ngx_uint_t                 i;
 736     ngx_shm_zone_t            *shm_zone;
 737     ngx_http_limit_req_ctx_t  *ctx;
 738
 739     value = cf->args->elts;
 740
 741     ctx = NULL;
 742     size = 0;
 743     rate = 1;
 744     scale = 1;
 745     name.len = 0;
 746
 747     for (i = 1; i < cf->args->nelts; i++) {
 748
 749         if (ngx_strncmp(value[i].data, "zone=", 5) == 0) {
 750
 751             name.data = value[i].data + 5;
 752
 753             p = (u_char *) ngx_strchr(name.data, ':');
 754
 755             if (p == NULL) {
 756                 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
 757                                    "invalid zone size \"%V\"", &value[i]);
 758                 return NGX_CONF_ERROR;
 759             }
 760
 761             name.len = p - name.data;
 762
 763             s.data = p + 1;
 764             s.len = value[i].data + value[i].len - s.data;
 765
 766             size = ngx_parse_size(&s);
 767
 768             if (size == NGX_ERROR) {
 769                 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
 770                                    "invalid zone size \"%V\"", &value[i]);
 771                 return NGX_CONF_ERROR;
 772             }
 773
 774             if (size < (ssize_t) (8 * ngx_pagesize)) {
 775                 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
 776                                    "zone \"%V\" is too small", &value[i]);
 777                 return NGX_CONF_ERROR;
 778             }
 779
 780             continue;
 781         }
 782
 783         if (ngx_strncmp(value[i].data, "rate=", 5) == 0) {
 784
 785             len = value[i].len;
 786             p = value[i].data + len - 3;
 787
 788             if (ngx_strncmp(p, "r/s", 3) == 0) {
 789                 scale = 1;
 790                 len -= 3;
 791
 792             } else if (ngx_strncmp(p, "r/m", 3) == 0) {
 793                 scale = 60;
 794                 len -= 3;
 795             }
 796
 797             rate = ngx_atoi(value[i].data + 5, len - 5);
 798             if (rate <= 0) {
 799                 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
 800                                    "invalid rate \"%V\"", &value[i]);
 801                 return NGX_CONF_ERROR;
 802             }
 803
 804             continue;
 805         }
 806
 807         if (value[i].data[0] == '$') {
 808
 809             value[i].len--;
 810             value[i].data++;
 811
 812             ctx = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_req_ctx_t));
 813             if (ctx == NULL) {
 814                 return NGX_CONF_ERROR;
 815             }
 816
 817             ctx->index = ngx_http_get_variable_index(cf, &value[i]);
 818             if (ctx->index == NGX_ERROR) {
 819                 return NGX_CONF_ERROR;
 820             }
 821
 822             ctx->var = value[i];
 823
 824             continue;
 825         }
 826
 827         ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
 828                            "invalid parameter \"%V\"", &value[i]);
 829         return NGX_CONF_ERROR;
 830     }
 831
 832     if (name.len == 0) {
 833         ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
 834                            "\"%V\" must have \"zone\" parameter",
 835                            &cmd->name);
 836         return NGX_CONF_ERROR;
 837     }
 838
 839     if (ctx == NULL) {
 840         ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
 841                            "no variable is defined for %V \"%V\"",
 842                            &cmd->name, &name);
 843         return NGX_CONF_ERROR;
 844     }
 845
 846     ctx->rate = rate * 1000 / scale;
 847
 848     shm_zone = ngx_shared_memory_add(cf, &name, size,
 849                                      &ngx_http_limit_req_module);
 850     if (shm_zone == NULL) {
 851         return NGX_CONF_ERROR;
 852     }
 853
 854     if (shm_zone->data) {
 855         ctx = shm_zone->data;
 856
 857         ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
 858                            "%V \"%V\" is already bound to variable \"%V\"",
 859                            &cmd->name, &name, &ctx->var);
 860         return NGX_CONF_ERROR;
 861     }
 862
 863     shm_zone->init = ngx_http_limit_req_init_zone;
 864     shm_zone->data = ctx;
 865
 866     return NGX_CONF_OK;
 867 }
 868
 869
 870 static char *
 871 ngx_http_limit_req(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
 872 {
 873     ngx_http_limit_req_conf_t  *lrcf = conf;
 874
 875     ngx_int_t                    burst;
 876     ngx_str_t                   *value, s;
 877     ngx_uint_t                   i, nodelay;
 878     ngx_shm_zone_t              *shm_zone;
 879     ngx_http_limit_req_limit_t  *limit, *limits;
 880
 881     value = cf->args->elts;
 882
 883     shm_zone = NULL;
 884     burst = 0;
 885     nodelay = 0;
 886
 887     for (i = 1; i < cf->args->nelts; i++) {
 888
 889         if (ngx_strncmp(value[i].data, "zone=", 5) == 0) {
 890
 891             s.len = value[i].len - 5;
 892             s.data = value[i].data + 5;
 893
 894             shm_zone = ngx_shared_memory_add(cf, &s, 0,
 895                                              &ngx_http_limit_req_module);
 896             if (shm_zone == NULL) {
 897                 return NGX_CONF_ERROR;
 898             }
 899
 900             continue;
 901         }
 902
 903         if (ngx_strncmp(value[i].data, "burst=", 6) == 0) {
 904
 905             burst = ngx_atoi(value[i].data + 6, value[i].len - 6);
 906             if (burst <= 0) {
 907                 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
 908                                    "invalid burst rate \"%V\"", &value[i]);
 909                 return NGX_CONF_ERROR;
 910             }
 911
 912             continue;
 913         }
 914
 915         if (ngx_strncmp(value[i].data, "nodelay", 7) == 0) {
 916             nodelay = 1;
 917             continue;
 918         }
 919
 920         ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
 921                            "invalid parameter \"%V\"", &value[i]);
 922         return NGX_CONF_ERROR;
 923     }
 924
 925     if (shm_zone == NULL) {
 926         ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
 927                            "\"%V\" must have \"zone\" parameter",
 928                            &cmd->name);
 929         return NGX_CONF_ERROR;
 930     }
 931
 932     if (shm_zone->data == NULL) {
 933         ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
 934                            "unknown limit_req_zone \"%V\"",
 935                            &shm_zone->shm.name);
 936         return NGX_CONF_ERROR;
 937     }
 938
 939     limits = lrcf->limits.elts;
 940
 941     if (limits == NULL) {
 942         if (ngx_array_init(&lrcf->limits, cf->pool, 1,
 943                            sizeof(ngx_http_limit_req_limit_t))
 944             != NGX_OK)
 945         {
 946             return NGX_CONF_ERROR;
 947         }
 948     }
 949
 950     for (i = 0; i < lrcf->limits.nelts; i++) {
 951         if (shm_zone == limits[i].shm_zone) {
 952             return "is duplicate";
 953         }
 954     }
 955
 956     limit = ngx_array_push(&lrcf->limits);
 957     if (limit == NULL) {
 958         return NGX_CONF_ERROR;
 959     }
 960
 961     limit->shm_zone = shm_zone;
 962     limit->burst = burst * 1000;
 963     limit->nodelay = nodelay;
 964
 965     return NGX_CONF_OK;
 966 }
 967
 968
 969 static ngx_int_t
 970 ngx_http_limit_req_init(ngx_conf_t *cf)
 971 {
 972     ngx_http_handler_pt        *h;
 973     ngx_http_core_main_conf_t  *cmcf;
 974
 975     cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
 976
 977     h = ngx_array_push(&cmcf->phases[NGX_HTTP_PREACCESS_PHASE].handlers);
 978     if (h == NULL) {
 979         return NGX_ERROR;
 980     }
 981
 982     *h = ngx_http_limit_req_handler;
 983
 984     return NGX_OK;
 985 }