530 lines
13 KiB
C
530 lines
13 KiB
C
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/*
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* Copyright (C) Igor Sysoev
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*/
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#include <ngx_config.h>
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#include <ngx_core.h>
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#include <ngx_http.h>
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typedef struct {
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u_char color;
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u_char len;
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u_short conn;
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u_char data[1];
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} ngx_http_limit_zone_node_t;
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typedef struct {
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ngx_shm_zone_t *shm_zone;
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ngx_rbtree_node_t *node;
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} ngx_http_limit_zone_cleanup_t;
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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;
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} ngx_http_limit_zone_ctx_t;
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typedef struct {
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ngx_shm_zone_t *shm_zone;
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ngx_uint_t conn;
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} ngx_http_limit_zone_conf_t;
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static void ngx_http_limit_zone_cleanup(void *data);
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static void *ngx_http_limit_zone_create_conf(ngx_conf_t *cf);
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static char *ngx_http_limit_zone_merge_conf(ngx_conf_t *cf, void *parent,
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void *child);
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static char *ngx_http_limit_zone(ngx_conf_t *cf, ngx_command_t *cmd,
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void *conf);
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static char *ngx_http_limit_conn(ngx_conf_t *cf, ngx_command_t *cmd,
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void *conf);
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static ngx_int_t ngx_http_limit_zone_init(ngx_conf_t *cf);
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static ngx_command_t ngx_http_limit_zone_commands[] = {
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{ ngx_string("limit_zone"),
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NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE3,
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ngx_http_limit_zone,
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0,
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0,
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NULL },
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{ 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,
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NGX_HTTP_LOC_CONF_OFFSET,
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0,
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NULL },
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ngx_null_command
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};
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static ngx_http_module_t ngx_http_limit_zone_module_ctx = {
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NULL, /* preconfiguration */
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ngx_http_limit_zone_init, /* postconfiguration */
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NULL, /* create main configuration */
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NULL, /* init main configuration */
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NULL, /* create server configuration */
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NULL, /* merge server configuration */
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ngx_http_limit_zone_create_conf, /* create location configration */
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ngx_http_limit_zone_merge_conf /* merge location configration */
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};
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ngx_module_t ngx_http_limit_zone_module = {
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NGX_MODULE_V1,
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&ngx_http_limit_zone_module_ctx, /* module context */
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ngx_http_limit_zone_commands, /* module directives */
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NGX_HTTP_MODULE, /* module type */
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NULL, /* init master */
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NULL, /* init module */
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NULL, /* init process */
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NULL, /* init thread */
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NULL, /* exit thread */
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NULL, /* exit process */
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NULL, /* exit master */
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NGX_MODULE_V1_PADDING
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};
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static ngx_int_t
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ngx_http_limit_zone_handler(ngx_http_request_t *r)
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{
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size_t len, n;
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uint32_t hash;
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ngx_int_t rc;
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ngx_slab_pool_t *shpool;
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ngx_rbtree_node_t *node, *sentinel;
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ngx_pool_cleanup_t *cln;
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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;
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ngx_http_limit_zone_conf_t *lzcf;
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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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}
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lzcf = ngx_http_get_module_loc_conf(r, ngx_http_limit_zone_module);
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if (lzcf->shm_zone == NULL) {
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return NGX_DECLINED;
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}
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ctx = lzcf->shm_zone->data;
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vv = ngx_http_get_indexed_variable(r, ctx->index);
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if (vv == NULL || vv->not_found) {
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return NGX_DECLINED;
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}
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len = vv->len;
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if (len == 0) {
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return NGX_DECLINED;
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}
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if (len > 255) {
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ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
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"the value of the \"%V\" variable "
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"is more than 255 bytes: \"%v\"",
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&ctx->var, vv);
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return NGX_DECLINED;
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}
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r->main->limit_zone_set = 1;
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hash = ngx_crc32_short(vv->data, len);
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cln = ngx_pool_cleanup_add(r->pool, sizeof(ngx_http_limit_zone_cleanup_t));
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if (cln == NULL) {
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return NGX_HTTP_INTERNAL_SERVER_ERROR;
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}
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shpool = (ngx_slab_pool_t *) lzcf->shm_zone->shm.addr;
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ngx_shmtx_lock(&shpool->mutex);
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node = ctx->rbtree->root;
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sentinel = ctx->rbtree->sentinel;
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while (node != sentinel) {
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if (hash < node->key) {
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node = node->left;
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continue;
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}
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if (hash > node->key) {
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node = node->right;
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continue;
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}
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/* hash == node->key */
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do {
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lz = (ngx_http_limit_zone_node_t *) &node->color;
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rc = ngx_memn2cmp(vv->data, lz->data, len, (size_t) lz->len);
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if (rc == 0) {
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if ((ngx_uint_t) lz->conn < lzcf->conn) {
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lz->conn++;
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goto done;
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}
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ngx_shmtx_unlock(&shpool->mutex);
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return NGX_HTTP_SERVICE_UNAVAILABLE;
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}
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node = (rc < 0) ? node->left : node->right;
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} while (node != sentinel && hash == node->key);
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break;
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}
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n = offsetof(ngx_rbtree_node_t, color)
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+ offsetof(ngx_http_limit_zone_node_t, data)
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+ len;
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node = ngx_slab_alloc_locked(shpool, n);
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if (node == NULL) {
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ngx_shmtx_unlock(&shpool->mutex);
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return NGX_HTTP_SERVICE_UNAVAILABLE;
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}
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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;
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ngx_memcpy(lz->data, vv->data, len);
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ngx_rbtree_insert(ctx->rbtree, node);
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done:
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ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
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"limit zone: %08XD %d", node->key, lz->conn);
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ngx_shmtx_unlock(&shpool->mutex);
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cln->handler = ngx_http_limit_zone_cleanup;
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lzcln = cln->data;
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lzcln->shm_zone = lzcf->shm_zone;
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lzcln->node = node;
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return NGX_DECLINED;
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}
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static void
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ngx_http_limit_zone_rbtree_insert_value(ngx_rbtree_node_t *temp,
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ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel)
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{
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ngx_http_limit_zone_node_t *lzn, *lznt;
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for ( ;; ) {
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if (node->key < temp->key) {
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if (temp->left == sentinel) {
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temp->left = node;
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break;
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}
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temp = temp->left;
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} else if (node->key > temp->key) {
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if (temp->right == sentinel) {
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temp->right = node;
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break;
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}
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temp = temp->right;
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} else { /* node->key == temp->key */
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lzn = (ngx_http_limit_zone_node_t *) &node->color;
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lznt = (ngx_http_limit_zone_node_t *) &temp->color;
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if (ngx_memn2cmp(lzn->data, lznt->data, lzn->len, lznt->len) < 0) {
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if (temp->left == sentinel) {
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temp->left = node;
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break;
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}
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temp = temp->left;
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} else {
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if (temp->right == sentinel) {
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temp->right = node;
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break;
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}
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temp = temp->right;
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}
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}
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}
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node->parent = temp;
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node->left = sentinel;
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node->right = sentinel;
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ngx_rbt_red(node);
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}
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static void
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ngx_http_limit_zone_cleanup(void *data)
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{
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ngx_http_limit_zone_cleanup_t *lzcln = data;
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ngx_slab_pool_t *shpool;
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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;
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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);
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ngx_log_debug2(NGX_LOG_DEBUG_HTTP, lzcln->shm_zone->shm.log, 0,
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"limit zone cleanup: %08XD %d", node->key, lz->conn);
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lz->conn--;
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if (lz->conn == 0) {
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ngx_rbtree_delete(ctx->rbtree, node);
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ngx_slab_free_locked(shpool, node);
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}
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ngx_shmtx_unlock(&shpool->mutex);
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}
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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;
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ngx_rbtree_node_t *sentinel;
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ngx_http_limit_zone_ctx_t *ctx;
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ctx = shm_zone->data;
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if (octx) {
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if (ngx_strcmp(ctx->var.data, octx->var.data) != 0) {
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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",
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&shm_zone->name, &ctx->var, &octx->var);
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return NGX_ERROR;
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}
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ctx->rbtree = octx->rbtree;
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return NGX_OK;
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}
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shpool = (ngx_slab_pool_t *) shm_zone->shm.addr;
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ctx->rbtree = ngx_slab_alloc(shpool, sizeof(ngx_rbtree_t));
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if (ctx->rbtree == NULL) {
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return NGX_ERROR;
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}
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sentinel = ngx_slab_alloc(shpool, sizeof(ngx_rbtree_node_t));
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if (sentinel == NULL) {
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return NGX_ERROR;
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}
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ngx_rbtree_sentinel_init(sentinel);
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ctx->rbtree->root = sentinel;
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ctx->rbtree->sentinel = sentinel;
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ctx->rbtree->insert = ngx_http_limit_zone_rbtree_insert_value;
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return NGX_OK;
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}
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static void *
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ngx_http_limit_zone_create_conf(ngx_conf_t *cf)
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{
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ngx_http_limit_zone_conf_t *conf;
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conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_zone_conf_t));
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if (conf == NULL) {
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return NGX_CONF_ERROR;
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}
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/*
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* set by ngx_pcalloc():
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*
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* conf->shm_zone = NULL;
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* conf->conn = 0;
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*/
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return conf;
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}
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static char *
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ngx_http_limit_zone_merge_conf(ngx_conf_t *cf, void *parent, void *child)
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{
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ngx_http_limit_zone_conf_t *prev = parent;
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ngx_http_limit_zone_conf_t *conf = child;
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if (conf->shm_zone == NULL) {
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*conf = *prev;
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}
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return NGX_CONF_OK;
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}
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static char *
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ngx_http_limit_zone(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
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{
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ssize_t n;
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ngx_str_t *value;
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ngx_shm_zone_t *shm_zone;
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ngx_http_limit_zone_ctx_t *ctx;
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value = cf->args->elts;
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if (value[2].data[0] != '$') {
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ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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"invalid variable name \"%V\"", &value[2]);
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return NGX_CONF_ERROR;
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}
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value[2].len--;
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value[2].data++;
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ctx = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_zone_ctx_t));
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if (ctx == NULL) {
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return NGX_CONF_ERROR;
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}
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ctx->index = ngx_http_get_variable_index(cf, &value[2]);
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if (ctx->index == NGX_ERROR) {
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return NGX_CONF_ERROR;
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}
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ctx->var = value[2];
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n = ngx_parse_size(&value[3]);
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if (n == NGX_ERROR) {
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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;
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}
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if (n < (ngx_int_t) (8 * ngx_pagesize)) {
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ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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"limit_zone \"%V\" is too small", &value[1]);
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return NGX_CONF_ERROR;
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}
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shm_zone = ngx_shared_memory_add(cf, &value[1], n,
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&ngx_http_limit_zone_module);
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if (shm_zone == NULL) {
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return NGX_CONF_ERROR;
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}
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if (shm_zone->data) {
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ctx = shm_zone->data;
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ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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"limit_zone \"%V\" is already bound to variable \"%V\"",
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&value[1], &ctx->var);
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return NGX_CONF_ERROR;
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}
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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;
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}
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static char *
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ngx_http_limit_conn(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
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{
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ngx_http_limit_zone_conf_t *lzcf = conf;
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ngx_int_t n;
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ngx_str_t *value;
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value = cf->args->elts;
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lzcf->shm_zone = ngx_shared_memory_add(cf, &value[1], 0,
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&ngx_http_limit_zone_module);
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if (lzcf->shm_zone == NULL) {
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return NGX_CONF_ERROR;
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}
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n = ngx_atoi(value[2].data, value[2].len);
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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;
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}
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if (n > 65535) {
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ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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"connection limit must be less 65536");
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return NGX_CONF_ERROR;
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}
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lzcf->conn = n;
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return NGX_CONF_OK;
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}
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static ngx_int_t
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ngx_http_limit_zone_init(ngx_conf_t *cf)
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{
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ngx_http_handler_pt *h;
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ngx_http_core_main_conf_t *cmcf;
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cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
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h = ngx_array_push(&cmcf->phases[NGX_HTTP_PREACCESS_PHASE].handlers);
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if (h == NULL) {
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return NGX_ERROR;
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}
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*h = ngx_http_limit_zone_handler;
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return NGX_OK;
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}
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