Default page

Your IP: 216.73.216.124
Server IP: 50.28.103.30
Server: Linux host.jcukjv-lwsites.com 4.18.0-553.22.1.el8_10.x86_64 #1 SMP Tue Sep 24 05:16:59 EDT 2024 x86_64
Server Software: nginx/1.28.0
PHP Version: 8.3.12
Buat File | Buat Folder

Dir : ~/www/server/nginx/src/src/http/modules/

Edit File: ngx_http_limit_req_module.c

/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */

#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>

#define NGX_HTTP_LIMIT_REQ_PASSED            1
#define NGX_HTTP_LIMIT_REQ_DELAYED           2
#define NGX_HTTP_LIMIT_REQ_REJECTED          3
#define NGX_HTTP_LIMIT_REQ_DELAYED_DRY_RUN   4
#define NGX_HTTP_LIMIT_REQ_REJECTED_DRY_RUN  5

typedef struct {
    u_char                       color;
    u_char                       dummy;
    u_short                      len;
    ngx_queue_t                  queue;
    ngx_msec_t                   last;
    /* integer value, 1 corresponds to 0.001 r/s */
    ngx_uint_t                   excess;
    ngx_uint_t                   count;
    u_char                       data[1];
} ngx_http_limit_req_node_t;

typedef struct {
    ngx_rbtree_t                  rbtree;
    ngx_rbtree_node_t             sentinel;
    ngx_queue_t                   queue;
} ngx_http_limit_req_shctx_t;

typedef struct {
    ngx_http_limit_req_shctx_t  *sh;
    ngx_slab_pool_t             *shpool;
    /* integer value, 1 corresponds to 0.001 r/s */
    ngx_uint_t                   rate;
    ngx_http_complex_value_t     key;
    ngx_http_limit_req_node_t   *node;
} ngx_http_limit_req_ctx_t;

typedef struct {
    ngx_shm_zone_t              *shm_zone;
    /* integer value, 1 corresponds to 0.001 r/s */
    ngx_uint_t                   burst;
    ngx_uint_t                   delay;
} ngx_http_limit_req_limit_t;

typedef struct {
    ngx_array_t                  limits;
    ngx_uint_t                   limit_log_level;
    ngx_uint_t                   delay_log_level;
    ngx_uint_t                   status_code;
    ngx_flag_t                   dry_run;
} ngx_http_limit_req_conf_t;

static void ngx_http_limit_req_delay(ngx_http_request_t *r);
static ngx_int_t ngx_http_limit_req_lookup(ngx_http_limit_req_limit_t *limit,
    ngx_uint_t hash, ngx_str_t *key, ngx_uint_t *ep, ngx_uint_t account);
static ngx_msec_t ngx_http_limit_req_account(ngx_http_limit_req_limit_t *limits,
    ngx_uint_t n, ngx_uint_t *ep, ngx_http_limit_req_limit_t **limit);
static void ngx_http_limit_req_unlock(ngx_http_limit_req_limit_t *limits,
    ngx_uint_t n);
static void ngx_http_limit_req_expire(ngx_http_limit_req_ctx_t *ctx,
    ngx_uint_t n);

static ngx_int_t ngx_http_limit_req_status_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static void *ngx_http_limit_req_create_conf(ngx_conf_t *cf);
static char *ngx_http_limit_req_merge_conf(ngx_conf_t *cf, void *parent,
    void *child);
static char *ngx_http_limit_req_zone(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static char *ngx_http_limit_req(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static ngx_int_t ngx_http_limit_req_add_variables(ngx_conf_t *cf);
static ngx_int_t ngx_http_limit_req_init(ngx_conf_t *cf);

static ngx_conf_enum_t  ngx_http_limit_req_log_levels[] = {
    { ngx_string("info"), NGX_LOG_INFO },
    { ngx_string("notice"), NGX_LOG_NOTICE },
    { ngx_string("warn"), NGX_LOG_WARN },
    { ngx_string("error"), NGX_LOG_ERR },
    { ngx_null_string, 0 }
};

static ngx_conf_num_bounds_t  ngx_http_limit_req_status_bounds = {
    ngx_conf_check_num_bounds, 400, 599
};

static ngx_command_t  ngx_http_limit_req_commands[] = {

{ ngx_string("limit_req_zone"),
      NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE3,
      ngx_http_limit_req_zone,
      0,
      0,
      NULL },

{ ngx_string("limit_req"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE123,
      ngx_http_limit_req,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

{ ngx_string("limit_req_log_level"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_enum_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_limit_req_conf_t, limit_log_level),
      &ngx_http_limit_req_log_levels },

{ ngx_string("limit_req_status"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_num_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_limit_req_conf_t, status_code),
      &ngx_http_limit_req_status_bounds },

{ ngx_string("limit_req_dry_run"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
      ngx_conf_set_flag_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_limit_req_conf_t, dry_run),
      NULL },

ngx_null_command
};

static ngx_http_module_t  ngx_http_limit_req_module_ctx = {
    ngx_http_limit_req_add_variables,      /* preconfiguration */
    ngx_http_limit_req_init,               /* postconfiguration */

NULL,                                  /* create main configuration */
    NULL,                                  /* init main configuration */

NULL,                                  /* create server configuration */
    NULL,                                  /* merge server configuration */

ngx_http_limit_req_create_conf,        /* create location configuration */
    ngx_http_limit_req_merge_conf          /* merge location configuration */
};

ngx_module_t  ngx_http_limit_req_module = {
    NGX_MODULE_V1,
    &ngx_http_limit_req_module_ctx,        /* module context */
    ngx_http_limit_req_commands,           /* module directives */
    NGX_HTTP_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};

static ngx_http_variable_t  ngx_http_limit_req_vars[] = {

{ ngx_string("limit_req_status"), NULL,
      ngx_http_limit_req_status_variable, 0, NGX_HTTP_VAR_NOCACHEABLE, 0 },

ngx_http_null_variable
};

static ngx_str_t  ngx_http_limit_req_status[] = {
    ngx_string("PASSED"),
    ngx_string("DELAYED"),
    ngx_string("REJECTED"),
    ngx_string("DELAYED_DRY_RUN"),
    ngx_string("REJECTED_DRY_RUN")
};

static ngx_int_t
ngx_http_limit_req_handler(ngx_http_request_t *r)
{
    uint32_t                     hash;
    ngx_str_t                    key;
    ngx_int_t                    rc;
    ngx_uint_t                   n, excess;
    ngx_msec_t                   delay;
    ngx_http_limit_req_ctx_t    *ctx;
    ngx_http_limit_req_conf_t   *lrcf;
    ngx_http_limit_req_limit_t  *limit, *limits;

if (r->main->limit_req_status) {
        return NGX_DECLINED;
    }

lrcf = ngx_http_get_module_loc_conf(r, ngx_http_limit_req_module);
    limits = lrcf->limits.elts;

excess = 0;

rc = NGX_DECLINED;

#if (NGX_SUPPRESS_WARN)
    limit = NULL;
#endif

for (n = 0; n < lrcf->limits.nelts; n++) {

limit = &limits[n];

ctx = limit->shm_zone->data;

if (ngx_http_complex_value(r, &ctx->key, &key) != NGX_OK) {
            ngx_http_limit_req_unlock(limits, n);
            return NGX_HTTP_INTERNAL_SERVER_ERROR;
        }

if (key.len == 0) {
            continue;
        }

if (key.len > 65535) {
            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                          "the value of the \"%V\" key "
                          "is more than 65535 bytes: \"%V\"",
                          &ctx->key.value, &key);
            continue;
        }

hash = ngx_crc32_short(key.data, key.len);

ngx_shmtx_lock(&ctx->shpool->mutex);

rc = ngx_http_limit_req_lookup(limit, hash, &key, &excess,
                                       (n == lrcf->limits.nelts - 1));

ngx_shmtx_unlock(&ctx->shpool->mutex);

ngx_log_debug4(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                       "limit_req[%ui]: %i %ui.%03ui",
                       n, rc, excess / 1000, excess % 1000);

if (rc != NGX_AGAIN) {
            break;
        }
    }

if (rc == NGX_DECLINED) {
        return NGX_DECLINED;
    }

if (rc == NGX_BUSY || rc == NGX_ERROR) {

if (rc == NGX_BUSY) {
            ngx_log_error(lrcf->limit_log_level, r->connection->log, 0,
                        "limiting requests%s, excess: %ui.%03ui by zone \"%V\"",
                        lrcf->dry_run ? ", dry run" : "",
                        excess / 1000, excess % 1000,
                        &limit->shm_zone->shm.name);
        }

ngx_http_limit_req_unlock(limits, n);

if (lrcf->dry_run) {
            r->main->limit_req_status = NGX_HTTP_LIMIT_REQ_REJECTED_DRY_RUN;
            return NGX_DECLINED;
        }

r->main->limit_req_status = NGX_HTTP_LIMIT_REQ_REJECTED;

return lrcf->status_code;
    }

/* rc == NGX_AGAIN || rc == NGX_OK */

if (rc == NGX_AGAIN) {
        excess = 0;
    }

delay = ngx_http_limit_req_account(limits, n, &excess, &limit);

if (!delay) {
        r->main->limit_req_status = NGX_HTTP_LIMIT_REQ_PASSED;
        return NGX_DECLINED;
    }

ngx_log_error(lrcf->delay_log_level, r->connection->log, 0,
                  "delaying request%s, excess: %ui.%03ui, by zone \"%V\"",
                  lrcf->dry_run ? ", dry run" : "",
                  excess / 1000, excess % 1000, &limit->shm_zone->shm.name);

if (lrcf->dry_run) {
        r->main->limit_req_status = NGX_HTTP_LIMIT_REQ_DELAYED_DRY_RUN;
        return NGX_DECLINED;
    }

r->main->limit_req_status = NGX_HTTP_LIMIT_REQ_DELAYED;

if (r->connection->read->ready) {
        ngx_post_event(r->connection->read, &ngx_posted_events);

} else {
        if (ngx_handle_read_event(r->connection->read, 0) != NGX_OK) {
            return NGX_HTTP_INTERNAL_SERVER_ERROR;
        }
    }

r->read_event_handler = ngx_http_test_reading;
    r->write_event_handler = ngx_http_limit_req_delay;

r->connection->write->delayed = 1;
    ngx_add_timer(r->connection->write, delay);

return NGX_AGAIN;
}

static void
ngx_http_limit_req_delay(ngx_http_request_t *r)
{
    ngx_event_t  *wev;

ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "limit_req delay");

wev = r->connection->write;

if (wev->delayed) {

if (ngx_handle_write_event(wev, 0) != NGX_OK) {
            ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
        }

return;
    }

if (ngx_handle_read_event(r->connection->read, 0) != NGX_OK) {
        ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
        return;
    }

r->read_event_handler = ngx_http_block_reading;
    r->write_event_handler = ngx_http_core_run_phases;

ngx_http_core_run_phases(r);
}

static void
ngx_http_limit_req_rbtree_insert_value(ngx_rbtree_node_t *temp,
    ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel)
{
    ngx_rbtree_node_t          **p;
    ngx_http_limit_req_node_t   *lrn, *lrnt;

for ( ;; ) {

if (node->key < temp->key) {

p = &temp->left;

} else if (node->key > temp->key) {

p = &temp->right;

} else { /* node->key == temp->key */

lrn = (ngx_http_limit_req_node_t *) &node->color;
            lrnt = (ngx_http_limit_req_node_t *) &temp->color;

p = (ngx_memn2cmp(lrn->data, lrnt->data, lrn->len, lrnt->len) < 0)
                ? &temp->left : &temp->right;
        }

if (*p == sentinel) {
            break;
        }

temp = *p;
    }

*p = node;
    node->parent = temp;
    node->left = sentinel;
    node->right = sentinel;
    ngx_rbt_red(node);
}

static ngx_int_t
ngx_http_limit_req_lookup(ngx_http_limit_req_limit_t *limit, ngx_uint_t hash,
    ngx_str_t *key, ngx_uint_t *ep, ngx_uint_t account)
{
    size_t                      size;
    ngx_int_t                   rc, excess;
    ngx_msec_t                  now;
    ngx_msec_int_t              ms;
    ngx_rbtree_node_t          *node, *sentinel;
    ngx_http_limit_req_ctx_t   *ctx;
    ngx_http_limit_req_node_t  *lr;

now = ngx_current_msec;

ctx = limit->shm_zone->data;

node = ctx->sh->rbtree.root;
    sentinel = ctx->sh->rbtree.sentinel;

while (node != sentinel) {

if (hash < node->key) {
            node = node->left;
            continue;
        }

if (hash > node->key) {
            node = node->right;
            continue;
        }

/* hash == node->key */

lr = (ngx_http_limit_req_node_t *) &node->color;

rc = ngx_memn2cmp(key->data, lr->data, key->len, (size_t) lr->len);

if (rc == 0) {
            ngx_queue_remove(&lr->queue);
            ngx_queue_insert_head(&ctx->sh->queue, &lr->queue);

ms = (ngx_msec_int_t) (now - lr->last);

if (ms < -60000) {
                ms = 1;

} else if (ms < 0) {
                ms = 0;
            }

excess = lr->excess - ctx->rate * ms / 1000 + 1000;

if (excess < 0) {
                excess = 0;
            }

*ep = excess;

if ((ngx_uint_t) excess > limit->burst) {
                return NGX_BUSY;
            }

if (account) {
                lr->excess = excess;

if (ms) {
                    lr->last = now;
                }

return NGX_OK;
            }

lr->count++;

ctx->node = lr;

return NGX_AGAIN;
        }

node = (rc < 0) ? node->left : node->right;
    }

*ep = 0;

size = offsetof(ngx_rbtree_node_t, color)
           + offsetof(ngx_http_limit_req_node_t, data)
           + key->len;

ngx_http_limit_req_expire(ctx, 1);

node = ngx_slab_alloc_locked(ctx->shpool, size);

if (node == NULL) {
        ngx_http_limit_req_expire(ctx, 0);

node = ngx_slab_alloc_locked(ctx->shpool, size);
        if (node == NULL) {
            ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0,
                          "could not allocate node%s", ctx->shpool->log_ctx);
            return NGX_ERROR;
        }
    }

node->key = hash;

lr = (ngx_http_limit_req_node_t *) &node->color;

lr->len = (u_short) key->len;
    lr->excess = 0;

ngx_memcpy(lr->data, key->data, key->len);

ngx_rbtree_insert(&ctx->sh->rbtree, node);

ngx_queue_insert_head(&ctx->sh->queue, &lr->queue);

if (account) {
        lr->last = now;
        lr->count = 0;
        return NGX_OK;
    }

lr->last = 0;
    lr->count = 1;

ctx->node = lr;

return NGX_AGAIN;
}

static ngx_msec_t
ngx_http_limit_req_account(ngx_http_limit_req_limit_t *limits, ngx_uint_t n,
    ngx_uint_t *ep, ngx_http_limit_req_limit_t **limit)
{
    ngx_int_t                   excess;
    ngx_msec_t                  now, delay, max_delay;
    ngx_msec_int_t              ms;
    ngx_http_limit_req_ctx_t   *ctx;
    ngx_http_limit_req_node_t  *lr;

excess = *ep;

if ((ngx_uint_t) excess <= (*limit)->delay) {
        max_delay = 0;

} else {
        ctx = (*limit)->shm_zone->data;
        max_delay = (excess - (*limit)->delay) * 1000 / ctx->rate;
    }

while (n--) {
        ctx = limits[n].shm_zone->data;
        lr = ctx->node;

if (lr == NULL) {
            continue;
        }

ngx_shmtx_lock(&ctx->shpool->mutex);

now = ngx_current_msec;
        ms = (ngx_msec_int_t) (now - lr->last);

if (ms < -60000) {
            ms = 1;

} else if (ms < 0) {
            ms = 0;
        }

excess = lr->excess - ctx->rate * ms / 1000 + 1000;

if (excess < 0) {
            excess = 0;
        }

if (ms) {
            lr->last = now;
        }

lr->excess = excess;
        lr->count--;

ngx_shmtx_unlock(&ctx->shpool->mutex);

ctx->node = NULL;

if ((ngx_uint_t) excess <= limits[n].delay) {
            continue;
        }

delay = (excess - limits[n].delay) * 1000 / ctx->rate;

if (delay > max_delay) {
            max_delay = delay;
            *ep = excess;
            *limit = &limits[n];
        }
    }

return max_delay;
}

static void
ngx_http_limit_req_unlock(ngx_http_limit_req_limit_t *limits, ngx_uint_t n)
{
    ngx_http_limit_req_ctx_t  *ctx;

while (n--) {
        ctx = limits[n].shm_zone->data;

if (ctx->node == NULL) {
            continue;
        }

ngx_shmtx_lock(&ctx->shpool->mutex);

ctx->node->count--;

ngx_shmtx_unlock(&ctx->shpool->mutex);

ctx->node = NULL;
    }
}

static void
ngx_http_limit_req_expire(ngx_http_limit_req_ctx_t *ctx, ngx_uint_t n)
{
    ngx_int_t                   excess;
    ngx_msec_t                  now;
    ngx_queue_t                *q;
    ngx_msec_int_t              ms;
    ngx_rbtree_node_t          *node;
    ngx_http_limit_req_node_t  *lr;

now = ngx_current_msec;

/*
     * n == 1 deletes one or two zero rate entries
     * n == 0 deletes oldest entry by force
     *        and one or two zero rate entries
     */

while (n < 3) {

if (ngx_queue_empty(&ctx->sh->queue)) {
            return;
        }

q = ngx_queue_last(&ctx->sh->queue);

lr = ngx_queue_data(q, ngx_http_limit_req_node_t, queue);

if (lr->count) {

/*
             * There is not much sense in looking further,
             * because we bump nodes on the lookup stage.
             */

return;
        }

if (n++ != 0) {

ms = (ngx_msec_int_t) (now - lr->last);
            ms = ngx_abs(ms);

if (ms < 60000) {
                return;
            }

excess = lr->excess - ctx->rate * ms / 1000;

if (excess > 0) {
                return;
            }
        }

ngx_queue_remove(q);

node = (ngx_rbtree_node_t *)
                   ((u_char *) lr - offsetof(ngx_rbtree_node_t, color));

ngx_rbtree_delete(&ctx->sh->rbtree, node);

ngx_slab_free_locked(ctx->shpool, node);
    }
}

static ngx_int_t
ngx_http_limit_req_init_zone(ngx_shm_zone_t *shm_zone, void *data)
{
    ngx_http_limit_req_ctx_t  *octx = data;

size_t                     len;
    ngx_http_limit_req_ctx_t  *ctx;

ctx = shm_zone->data;

if (octx) {
        if (ctx->key.value.len != octx->key.value.len
            || ngx_strncmp(ctx->key.value.data, octx->key.value.data,
                           ctx->key.value.len)
               != 0)
        {
            ngx_log_error(NGX_LOG_EMERG, shm_zone->shm.log, 0,
                          "limit_req \"%V\" uses the \"%V\" key "
                          "while previously it used the \"%V\" key",
                          &shm_zone->shm.name, &ctx->key.value,
                          &octx->key.value);
            return NGX_ERROR;
        }

ctx->sh = octx->sh;
        ctx->shpool = octx->shpool;

return NGX_OK;
    }

ctx->shpool = (ngx_slab_pool_t *) shm_zone->shm.addr;

if (shm_zone->shm.exists) {
        ctx->sh = ctx->shpool->data;

return NGX_OK;
    }

ctx->sh = ngx_slab_alloc(ctx->shpool, sizeof(ngx_http_limit_req_shctx_t));
    if (ctx->sh == NULL) {
        return NGX_ERROR;
    }

ctx->shpool->data = ctx->sh;

ngx_rbtree_init(&ctx->sh->rbtree, &ctx->sh->sentinel,
                    ngx_http_limit_req_rbtree_insert_value);

ngx_queue_init(&ctx->sh->queue);

len = sizeof(" in limit_req zone \"\"") + shm_zone->shm.name.len;

ctx->shpool->log_ctx = ngx_slab_alloc(ctx->shpool, len);
    if (ctx->shpool->log_ctx == NULL) {
        return NGX_ERROR;
    }

ngx_sprintf(ctx->shpool->log_ctx, " in limit_req zone \"%V\"%Z",
                &shm_zone->shm.name);

ctx->shpool->log_nomem = 0;

return NGX_OK;
}

static ngx_int_t
ngx_http_limit_req_status_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data)
{
    if (r->main->limit_req_status == 0) {
        v->not_found = 1;
        return NGX_OK;
    }

v->valid = 1;
    v->no_cacheable = 0;
    v->not_found = 0;
    v->len = ngx_http_limit_req_status[r->main->limit_req_status - 1].len;
    v->data = ngx_http_limit_req_status[r->main->limit_req_status - 1].data;

return NGX_OK;
}

static void *
ngx_http_limit_req_create_conf(ngx_conf_t *cf)
{
    ngx_http_limit_req_conf_t  *conf;

conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_req_conf_t));
    if (conf == NULL) {
        return NULL;
    }

/*
     * set by ngx_pcalloc():
     *
     *     conf->limits.elts = NULL;
     */

conf->limit_log_level = NGX_CONF_UNSET_UINT;
    conf->status_code = NGX_CONF_UNSET_UINT;
    conf->dry_run = NGX_CONF_UNSET;

return conf;
}

static char *
ngx_http_limit_req_merge_conf(ngx_conf_t *cf, void *parent, void *child)
{
    ngx_http_limit_req_conf_t *prev = parent;
    ngx_http_limit_req_conf_t *conf = child;

if (conf->limits.elts == NULL) {
        conf->limits = prev->limits;
    }

ngx_conf_merge_uint_value(conf->limit_log_level, prev->limit_log_level,
                              NGX_LOG_ERR);

conf->delay_log_level = (conf->limit_log_level == NGX_LOG_INFO) ?
                                NGX_LOG_INFO : conf->limit_log_level + 1;

ngx_conf_merge_uint_value(conf->status_code, prev->status_code,
                              NGX_HTTP_SERVICE_UNAVAILABLE);

ngx_conf_merge_value(conf->dry_run, prev->dry_run, 0);

return NGX_CONF_OK;
}

static char *
ngx_http_limit_req_zone(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    u_char                            *p;
    size_t                             len;
    ssize_t                            size;
    ngx_str_t                         *value, name, s;
    ngx_int_t                          rate, scale;
    ngx_uint_t                         i;
    ngx_shm_zone_t                    *shm_zone;
    ngx_http_limit_req_ctx_t          *ctx;
    ngx_http_compile_complex_value_t   ccv;

value = cf->args->elts;

ctx = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_req_ctx_t));
    if (ctx == NULL) {
        return NGX_CONF_ERROR;
    }

ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t));

ccv.cf = cf;
    ccv.value = &value[1];
    ccv.complex_value = &ctx->key;

if (ngx_http_compile_complex_value(&ccv) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

size = 0;
    rate = 1;
    scale = 1;
    name.len = 0;

for (i = 2; i < cf->args->nelts; i++) {

if (ngx_strncmp(value[i].data, "zone=", 5) == 0) {

name.data = value[i].data + 5;

p = (u_char *) ngx_strchr(name.data, ':');

if (p == NULL) {
                ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                   "invalid zone size \"%V\"", &value[i]);
                return NGX_CONF_ERROR;
            }

name.len = p - name.data;

s.data = p + 1;
            s.len = value[i].data + value[i].len - s.data;

size = ngx_parse_size(&s);

if (size == NGX_ERROR) {
                ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                   "invalid zone size \"%V\"", &value[i]);
                return NGX_CONF_ERROR;
            }

if (size < (ssize_t) (8 * ngx_pagesize)) {
                ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                   "zone \"%V\" is too small", &value[i]);
                return NGX_CONF_ERROR;
            }

continue;
        }

if (ngx_strncmp(value[i].data, "rate=", 5) == 0) {

len = value[i].len;
            p = value[i].data + len - 3;

if (ngx_strncmp(p, "r/s", 3) == 0) {
                scale = 1;
                len -= 3;

} else if (ngx_strncmp(p, "r/m", 3) == 0) {
                scale = 60;
                len -= 3;
            }

rate = ngx_atoi(value[i].data + 5, len - 5);
            if (rate <= 0) {
                ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                   "invalid rate \"%V\"", &value[i]);
                return NGX_CONF_ERROR;
            }

continue;
        }

ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "invalid parameter \"%V\"", &value[i]);
        return NGX_CONF_ERROR;
    }

if (name.len == 0) {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "\"%V\" must have \"zone\" parameter",
                           &cmd->name);
        return NGX_CONF_ERROR;
    }

ctx->rate = rate * 1000 / scale;

shm_zone = ngx_shared_memory_add(cf, &name, size,
                                     &ngx_http_limit_req_module);
    if (shm_zone == NULL) {
        return NGX_CONF_ERROR;
    }

if (shm_zone->data) {
        ctx = shm_zone->data;

ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "%V \"%V\" is already bound to key \"%V\"",
                           &cmd->name, &name, &ctx->key.value);
        return NGX_CONF_ERROR;
    }

shm_zone->init = ngx_http_limit_req_init_zone;
    shm_zone->data = ctx;

return NGX_CONF_OK;
}

static char *
ngx_http_limit_req(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_limit_req_conf_t  *lrcf = conf;

ngx_int_t                    burst, delay;
    ngx_str_t                   *value, s;
    ngx_uint_t                   i;
    ngx_shm_zone_t              *shm_zone;
    ngx_http_limit_req_limit_t  *limit, *limits;

value = cf->args->elts;

shm_zone = NULL;
    burst = 0;
    delay = 0;

for (i = 1; i < cf->args->nelts; i++) {

if (ngx_strncmp(value[i].data, "zone=", 5) == 0) {

s.len = value[i].len - 5;
            s.data = value[i].data + 5;

shm_zone = ngx_shared_memory_add(cf, &s, 0,
                                             &ngx_http_limit_req_module);
            if (shm_zone == NULL) {
                return NGX_CONF_ERROR;
            }

continue;
        }

if (ngx_strncmp(value[i].data, "burst=", 6) == 0) {

burst = ngx_atoi(value[i].data + 6, value[i].len - 6);
            if (burst <= 0) {
                ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                   "invalid burst value \"%V\"", &value[i]);
                return NGX_CONF_ERROR;
            }

continue;
        }

if (ngx_strncmp(value[i].data, "delay=", 6) == 0) {

delay = ngx_atoi(value[i].data + 6, value[i].len - 6);
            if (delay <= 0) {
                ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                   "invalid delay value \"%V\"", &value[i]);
                return NGX_CONF_ERROR;
            }

continue;
        }

if (ngx_strcmp(value[i].data, "nodelay") == 0) {
            delay = NGX_MAX_INT_T_VALUE / 1000;
            continue;
        }

ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "invalid parameter \"%V\"", &value[i]);
        return NGX_CONF_ERROR;
    }

if (shm_zone == NULL) {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "\"%V\" must have \"zone\" parameter",
                           &cmd->name);
        return NGX_CONF_ERROR;
    }

limits = lrcf->limits.elts;

if (limits == NULL) {
        if (ngx_array_init(&lrcf->limits, cf->pool, 1,
                           sizeof(ngx_http_limit_req_limit_t))
            != NGX_OK)
        {
            return NGX_CONF_ERROR;
        }
    }

for (i = 0; i < lrcf->limits.nelts; i++) {
        if (shm_zone == limits[i].shm_zone) {
            return "is duplicate";
        }
    }

limit = ngx_array_push(&lrcf->limits);
    if (limit == NULL) {
        return NGX_CONF_ERROR;
    }

limit->shm_zone = shm_zone;
    limit->burst = burst * 1000;
    limit->delay = delay * 1000;

return NGX_CONF_OK;
}

static ngx_int_t
ngx_http_limit_req_add_variables(ngx_conf_t *cf)
{
    ngx_http_variable_t  *var, *v;

for (v = ngx_http_limit_req_vars; v->name.len; v++) {
        var = ngx_http_add_variable(cf, &v->name, v->flags);
        if (var == NULL) {
            return NGX_ERROR;
        }

var->get_handler = v->get_handler;
        var->data = v->data;
    }

return NGX_OK;
}

static ngx_int_t
ngx_http_limit_req_init(ngx_conf_t *cf)
{
    ngx_http_handler_pt        *h;
    ngx_http_core_main_conf_t  *cmcf;

cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);

h = ngx_array_push(&cmcf->phases[NGX_HTTP_PREACCESS_PHASE].handlers);
    if (h == NULL) {
        return NGX_ERROR;
    }

*h = ngx_http_limit_req_handler;

return NGX_OK;
}