nginx/src/http/modules/ngx_http_limit_zone_module.c

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/*
* Copyright (C) Igor Sysoev
*/
#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>
typedef struct {
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u_char color;
u_char len;
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u_short conn;
u_char data[1];
} ngx_http_limit_zone_node_t;
typedef struct {
ngx_shm_zone_t *shm_zone;
ngx_rbtree_node_t *node;
} ngx_http_limit_zone_cleanup_t;
typedef struct {
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ngx_rbtree_t *rbtree;
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ngx_int_t index;
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ngx_str_t var;
} ngx_http_limit_zone_ctx_t;
typedef struct {
ngx_shm_zone_t *shm_zone;
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ngx_uint_t conn;
} ngx_http_limit_zone_conf_t;
static void ngx_http_limit_zone_cleanup(void *data);
static void *ngx_http_limit_zone_create_conf(ngx_conf_t *cf);
static char *ngx_http_limit_zone_merge_conf(ngx_conf_t *cf, void *parent,
void *child);
static char *ngx_http_limit_zone(ngx_conf_t *cf, ngx_command_t *cmd,
void *conf);
static char *ngx_http_limit_conn(ngx_conf_t *cf, ngx_command_t *cmd,
void *conf);
static ngx_int_t ngx_http_limit_zone_init(ngx_conf_t *cf);
static ngx_command_t ngx_http_limit_zone_commands[] = {
{ ngx_string("limit_zone"),
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NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE3,
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ngx_http_limit_zone,
0,
0,
NULL },
{ ngx_string("limit_conn"),
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NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE2,
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ngx_http_limit_conn,
NGX_HTTP_LOC_CONF_OFFSET,
0,
NULL },
ngx_null_command
};
static ngx_http_module_t ngx_http_limit_zone_module_ctx = {
NULL, /* preconfiguration */
ngx_http_limit_zone_init, /* postconfiguration */
NULL, /* create main configuration */
NULL, /* init main configuration */
NULL, /* create server configuration */
NULL, /* merge server configuration */
ngx_http_limit_zone_create_conf, /* create location configration */
ngx_http_limit_zone_merge_conf /* merge location configration */
};
ngx_module_t ngx_http_limit_zone_module = {
NGX_MODULE_V1,
&ngx_http_limit_zone_module_ctx, /* module context */
ngx_http_limit_zone_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_zone_handler(ngx_http_request_t *r)
{
size_t len, n;
uint32_t hash;
ngx_slab_pool_t *shpool;
ngx_rbtree_node_t *node, *sentinel;
ngx_pool_cleanup_t *cln;
ngx_http_variable_value_t *vv;
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ngx_http_limit_zone_ctx_t *ctx;
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ngx_http_limit_zone_node_t *lz;
ngx_http_limit_zone_conf_t *lzcf;
ngx_http_limit_zone_cleanup_t *lzcln;
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if (r->main->limit_zone_set) {
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return NGX_DECLINED;
}
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lzcf = ngx_http_get_module_loc_conf(r, ngx_http_limit_zone_module);
if (lzcf->shm_zone == NULL) {
return NGX_DECLINED;
}
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ctx = lzcf->shm_zone->data;
vv = ngx_http_get_indexed_variable(r, ctx->index);
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if (vv == NULL || vv->not_found) {
return NGX_DECLINED;
}
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r->limit_zone_set = 1;
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len = vv->len;
hash = ngx_crc32_short(vv->data, len);
cln = ngx_pool_cleanup_add(r->pool, sizeof(ngx_http_limit_zone_cleanup_t));
if (cln == NULL) {
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
shpool = (ngx_slab_pool_t *) lzcf->shm_zone->shm.addr;
ngx_shmtx_lock(&shpool->mutex);
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node = ctx->rbtree->root;
sentinel = ctx->rbtree->sentinel;
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while (node != sentinel) {
if (hash < node->key) {
node = node->left;
continue;
}
if (hash > node->key) {
node = node->right;
continue;
}
if (hash == node->key ){
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lz = (ngx_http_limit_zone_node_t *) &node->color;
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if (len == (size_t) lz->len
&& ngx_strncmp(lz->data, vv->data, len) == 0)
{
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if ((ngx_uint_t) lz->conn < lzcf->conn) {
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lz->conn++;
goto done;
}
ngx_shmtx_unlock(&shpool->mutex);
return NGX_HTTP_SERVICE_UNAVAILABLE;
}
}
}
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n = offsetof(ngx_rbtree_node_t, color)
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+ offsetof(ngx_http_limit_zone_node_t, data)
+ len;
node = ngx_slab_alloc_locked(shpool, n);
if (node == NULL) {
ngx_shmtx_unlock(&shpool->mutex);
return NGX_HTTP_SERVICE_UNAVAILABLE;
}
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lz = (ngx_http_limit_zone_node_t *) &node->color;
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node->key = hash;
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lz->len = (u_char) len;
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lz->conn = 1;
ngx_memcpy(lz->data, vv->data, len);
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ngx_rbtree_insert(ctx->rbtree, node);
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done:
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"limit zone: %08XD %d", node->key, lz->conn);
ngx_shmtx_unlock(&shpool->mutex);
cln->handler = ngx_http_limit_zone_cleanup;
lzcln = cln->data;
lzcln->shm_zone = lzcf->shm_zone;
lzcln->node = node;
return NGX_DECLINED;
}
static void
ngx_http_limit_zone_cleanup(void *data)
{
ngx_http_limit_zone_cleanup_t *lzcln = data;
ngx_slab_pool_t *shpool;
ngx_rbtree_node_t *node;
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ngx_http_limit_zone_ctx_t *ctx;
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ngx_http_limit_zone_node_t *lz;
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ctx = lzcln->shm_zone->data;
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shpool = (ngx_slab_pool_t *) lzcln->shm_zone->shm.addr;
node = lzcln->node;
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lz = (ngx_http_limit_zone_node_t *) &node->color;
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ngx_shmtx_lock(&shpool->mutex);
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, lzcln->shm_zone->shm.log, 0,
"limit zone cleanup: %08XD %d", node->key, lz->conn);
lz->conn--;
if (lz->conn == 0) {
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ngx_rbtree_delete(ctx->rbtree, node);
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ngx_slab_free_locked(shpool, node);
}
ngx_shmtx_unlock(&shpool->mutex);
}
static ngx_int_t
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ngx_http_limit_zone_init_zone(ngx_shm_zone_t *shm_zone, void *data)
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{
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ngx_http_limit_zone_ctx_t *octx = data;
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ngx_slab_pool_t *shpool;
ngx_rbtree_node_t *sentinel;
ngx_http_limit_zone_ctx_t *ctx;
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ctx = shm_zone->data;
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if (octx) {
if (ngx_strcmp(ctx->var.data, octx->var.data) != 0) {
ngx_log_error(NGX_LOG_EMERG, shm_zone->shm.log, 0,
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"limit_zone \"%V\" uses the \"%V\" variable "
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"while previously it used the \"%V\" variable",
&shm_zone->name, &ctx->var, &octx->var);
return NGX_ERROR;
}
ctx->rbtree = octx->rbtree;
return NGX_OK;
}
shpool = (ngx_slab_pool_t *) shm_zone->shm.addr;
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ctx->rbtree = ngx_slab_alloc(shpool, sizeof(ngx_rbtree_t));
if (ctx->rbtree == NULL) {
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return NGX_ERROR;
}
sentinel = ngx_slab_alloc(shpool, sizeof(ngx_rbtree_node_t));
if (sentinel == NULL) {
return NGX_ERROR;
}
ngx_rbtree_sentinel_init(sentinel);
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ctx->rbtree->root = sentinel;
ctx->rbtree->sentinel = sentinel;
ctx->rbtree->insert = ngx_rbtree_insert_value;
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return NGX_OK;
}
static void *
ngx_http_limit_zone_create_conf(ngx_conf_t *cf)
{
ngx_http_limit_zone_conf_t *conf;
conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_zone_conf_t));
if (conf == NULL) {
return NGX_CONF_ERROR;
}
/*
* set by ngx_pcalloc():
*
* conf->shm_zone = NULL;
* conf->conn = 0;
*/
return conf;
}
static char *
ngx_http_limit_zone_merge_conf(ngx_conf_t *cf, void *parent, void *child)
{
ngx_http_limit_zone_conf_t *prev = parent;
ngx_http_limit_zone_conf_t *conf = child;
if (conf->shm_zone == NULL) {
*conf = *prev;
}
return NGX_CONF_OK;
}
static char *
ngx_http_limit_zone(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
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ssize_t n;
ngx_str_t *value;
ngx_shm_zone_t *shm_zone;
ngx_http_limit_zone_ctx_t *ctx;
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value = cf->args->elts;
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if (value[2].data[0] != '$') {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"invalid variable name \"%V\"", &value[2]);
return NGX_CONF_ERROR;
}
value[2].len--;
value[2].data++;
ctx = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_zone_ctx_t));
if (ctx == NULL) {
return NGX_CONF_ERROR;
}
ctx->index = ngx_http_get_variable_index(cf, &value[2]);
if (ctx->index == NGX_ERROR) {
return NGX_CONF_ERROR;
}
ctx->var = value[2];
n = ngx_parse_size(&value[3]);
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if (n == NGX_ERROR) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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"invalid size of limit_zone \"%V\"", &value[3]);
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return NGX_CONF_ERROR;
}
if (n < (ngx_int_t) (8 * ngx_pagesize)) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"limit_zone \"%V\" is too small", &value[1]);
return NGX_CONF_ERROR;
}
shm_zone = ngx_shared_memory_add(cf, &value[1], n,
&ngx_http_limit_zone_module);
if (shm_zone == NULL) {
return NGX_CONF_ERROR;
}
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if (shm_zone->data) {
ctx = shm_zone->data;
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"limit_zone \"%V\" is already bound to variable \"%V\"",
&value[1], &ctx->var);
return NGX_CONF_ERROR;
}
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shm_zone->init = ngx_http_limit_zone_init_zone;
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shm_zone->data = ctx;
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return NGX_CONF_OK;
}
static char *
ngx_http_limit_conn(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
ngx_http_limit_zone_conf_t *lzcf = conf;
ngx_int_t n;
ngx_str_t *value;
value = cf->args->elts;
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lzcf->shm_zone = ngx_shared_memory_add(cf, &value[1], 0,
&ngx_http_limit_zone_module);
if (lzcf->shm_zone == NULL) {
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return NGX_CONF_ERROR;
}
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n = ngx_atoi(value[2].data, value[2].len);
if (n <= 0) {
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ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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"invalid number of connections \"%V\"", &value[2]);
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return NGX_CONF_ERROR;
}
lzcf->conn = n;
return NGX_CONF_OK;
}
static ngx_int_t
ngx_http_limit_zone_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_zone_handler;
return NGX_OK;
}