blob: 718fae8e2e29c8e37578ed73ff4b78c05032d4d2 [file] [log] [blame]
/*
* Copyright (C) Igor Sysoev
*/
#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>
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;
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_int_t index;
ngx_str_t var;
} 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 limit_log_level;
ngx_uint_t delay_log_level;
ngx_uint_t nodelay; /* unsigned nodelay:1 */
} 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_conf_t *lrcf,
ngx_uint_t hash, u_char *data, size_t len, ngx_uint_t *ep);
static void ngx_http_limit_req_expire(ngx_http_limit_req_ctx_t *ctx,
ngx_uint_t n);
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_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_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_null_command
};
static ngx_http_module_t ngx_http_limit_req_module_ctx = {
NULL, /* 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 configration */
ngx_http_limit_req_merge_conf /* merge location configration */
};
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_int_t
ngx_http_limit_req_handler(ngx_http_request_t *r)
{
size_t len, n;
uint32_t hash;
ngx_int_t rc;
ngx_uint_t excess;
ngx_time_t *tp;
ngx_rbtree_node_t *node;
ngx_http_variable_value_t *vv;
ngx_http_limit_req_ctx_t *ctx;
ngx_http_limit_req_node_t *lr;
ngx_http_limit_req_conf_t *lrcf;
if (r->main->limit_req_set) {
return NGX_DECLINED;
}
lrcf = ngx_http_get_module_loc_conf(r, ngx_http_limit_req_module);
if (lrcf->shm_zone == NULL) {
return NGX_DECLINED;
}
ctx = lrcf->shm_zone->data;
vv = ngx_http_get_indexed_variable(r, ctx->index);
if (vv == NULL || vv->not_found) {
return NGX_DECLINED;
}
len = vv->len;
if (len == 0) {
return NGX_DECLINED;
}
if (len > 65535) {
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
"the value of the \"%V\" variable "
"is more than 65535 bytes: \"%v\"",
&ctx->var, vv);
return NGX_DECLINED;
}
r->main->limit_req_set = 1;
hash = ngx_crc32_short(vv->data, len);
ngx_shmtx_lock(&ctx->shpool->mutex);
ngx_http_limit_req_expire(ctx, 1);
rc = ngx_http_limit_req_lookup(lrcf, hash, vv->data, len, &excess);
ngx_log_debug3(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"limit_req: %i %ui.%03ui", rc, excess / 1000, excess % 1000);
if (rc == NGX_DECLINED) {
n = offsetof(ngx_rbtree_node_t, color)
+ offsetof(ngx_http_limit_req_node_t, data)
+ len;
node = ngx_slab_alloc_locked(ctx->shpool, n);
if (node == NULL) {
ngx_http_limit_req_expire(ctx, 0);
node = ngx_slab_alloc_locked(ctx->shpool, n);
if (node == NULL) {
ngx_shmtx_unlock(&ctx->shpool->mutex);
return NGX_HTTP_SERVICE_UNAVAILABLE;
}
}
lr = (ngx_http_limit_req_node_t *) &node->color;
node->key = hash;
lr->len = (u_char) len;
tp = ngx_timeofday();
lr->last = (ngx_msec_t) (tp->sec * 1000 + tp->msec);
lr->excess = 0;
ngx_memcpy(lr->data, vv->data, len);
ngx_rbtree_insert(&ctx->sh->rbtree, node);
ngx_queue_insert_head(&ctx->sh->queue, &lr->queue);
ngx_shmtx_unlock(&ctx->shpool->mutex);
return NGX_DECLINED;
}
ngx_shmtx_unlock(&ctx->shpool->mutex);
if (rc == NGX_OK) {
return NGX_DECLINED;
}
if (rc == NGX_BUSY) {
ngx_log_error(lrcf->limit_log_level, r->connection->log, 0,
"limiting requests, excess: %ui.%03ui by zone \"%V\"",
excess / 1000, excess % 1000, &lrcf->shm_zone->shm.name);
return NGX_HTTP_SERVICE_UNAVAILABLE;
}
/* rc == NGX_AGAIN */
if (lrcf->nodelay) {
return NGX_DECLINED;
}
ngx_log_error(lrcf->delay_log_level, r->connection->log, 0,
"delaying request, excess: %ui.%03ui, by zone \"%V\"",
excess / 1000, excess % 1000, &lrcf->shm_zone->shm.name);
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;
ngx_add_timer(r->connection->write,
(ngx_msec_t) excess * 1000 / ctx->rate);
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->timedout) {
if (ngx_handle_write_event(wev, 0) != NGX_OK) {
ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
}
return;
}
wev->timedout = 0;
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_conf_t *lrcf, ngx_uint_t hash,
u_char *data, size_t len, ngx_uint_t *ep)
{
ngx_int_t rc, excess;
ngx_time_t *tp;
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;
ctx = lrcf->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 */
do {
lr = (ngx_http_limit_req_node_t *) &node->color;
rc = ngx_memn2cmp(data, lr->data, len, (size_t) lr->len);
if (rc == 0) {
ngx_queue_remove(&lr->queue);
ngx_queue_insert_head(&ctx->sh->queue, &lr->queue);
tp = ngx_timeofday();
now = (ngx_msec_t) (tp->sec * 1000 + tp->msec);
ms = (ngx_msec_int_t) (now - lr->last);
excess = lr->excess - ctx->rate * ngx_abs(ms) / 1000 + 1000;
if (excess < 0) {
excess = 0;
}
*ep = excess;
if ((ngx_uint_t) excess > lrcf->burst) {
return NGX_BUSY;
}
lr->excess = excess;
lr->last = now;
if (excess) {
return NGX_AGAIN;
}
return NGX_OK;
}
node = (rc < 0) ? node->left : node->right;
} while (node != sentinel && hash == node->key);
break;
}
*ep = 0;
return NGX_DECLINED;
}
static void
ngx_http_limit_req_expire(ngx_http_limit_req_ctx_t *ctx, ngx_uint_t n)
{
ngx_int_t excess;
ngx_time_t *tp;
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;
tp = ngx_timeofday();
now = (ngx_msec_t) (tp->sec * 1000 + tp->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 (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 (ngx_strcmp(ctx->var.data, octx->var.data) != 0) {
ngx_log_error(NGX_LOG_EMERG, shm_zone->shm.log, 0,
"limit_req \"%V\" uses the \"%V\" variable "
"while previously it used the \"%V\" variable",
&shm_zone->shm.name, &ctx->var, &octx->var);
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);
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->shm_zone = NULL;
* conf->burst = 0;
* conf->nodelay = 0;
*/
conf->limit_log_level = NGX_CONF_UNSET_UINT;
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->shm_zone == NULL) {
*conf = *prev;
}
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;
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 size, len;
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;
value = cf->args->elts;
ctx = NULL;
size = 0;
rate = 1;
scale = 1;
name.len = 0;
for (i = 1; 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) {
*p = '\0';
name.len = p - name.data;
p++;
s.len = value[i].data + value[i].len - p;
s.data = p;
size = ngx_parse_size(&s);
if (size > 8191) {
continue;
}
}
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"invalid zone size \"%V\"", &value[i]);
return NGX_CONF_ERROR;
}
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 <= NGX_ERROR) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"invalid rate \"%V\"", &value[i]);
return NGX_CONF_ERROR;
}
continue;
}
if (value[i].data[0] == '$') {
value[i].len--;
value[i].data++;
ctx = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_req_ctx_t));
if (ctx == NULL) {
return NGX_CONF_ERROR;
}
ctx->index = ngx_http_get_variable_index(cf, &value[i]);
if (ctx->index == NGX_ERROR) {
return NGX_CONF_ERROR;
}
ctx->var = value[i];
continue;
}
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"invalid parameter \"%V\"", &value[i]);
return NGX_CONF_ERROR;
}
if (name.len == 0 || size == 0) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"\"%V\" must have \"zone\" parameter",
&cmd->name);
return NGX_CONF_ERROR;
}
if (ctx == NULL) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"no variable is defined for limit_req_zone \"%V\"",
&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,
"limit_req_zone \"%V\" is already bound to variable \"%V\"",
&value[1], &ctx->var);
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;
ngx_str_t *value, s;
ngx_uint_t i;
if (lrcf->shm_zone) {
return "is duplicate";
}
value = cf->args->elts;
burst = 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;
lrcf->shm_zone = ngx_shared_memory_add(cf, &s, 0,
&ngx_http_limit_req_module);
if (lrcf->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 rate \"%V\"", &value[i]);
return NGX_CONF_ERROR;
}
continue;
}
if (ngx_strncmp(value[i].data, "nodelay", 7) == 0) {
lrcf->nodelay = 1;
continue;
}
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"invalid parameter \"%V\"", &value[i]);
return NGX_CONF_ERROR;
}
if (lrcf->shm_zone == NULL) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"\"%V\" must have \"zone\" parameter",
&cmd->name);
return NGX_CONF_ERROR;
}
if (lrcf->shm_zone->data == NULL) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"unknown limit_req_zone \"%V\"",
&lrcf->shm_zone->shm.name);
return NGX_CONF_ERROR;
}
lrcf->burst = burst * 1000;
return NGX_CONF_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;
}