Mercurial > hg > nginx
view src/http/modules/ngx_http_limit_conn_module.c @ 7985:ec2e6893caaa
Simplified sendfile(SF_NODISKIO) usage.
Starting with FreeBSD 11, there is no need to use AIO operations to preload
data into cache for sendfile(SF_NODISKIO) to work. Instead, sendfile()
handles non-blocking loading data from disk by itself. It still can, however,
return EBUSY if a page is already being loaded (for example, by a different
process). If this happens, we now post an event for the next event loop
iteration, so sendfile() is retried "after a short period", as manpage
recommends.
The limit of the number of EBUSY tolerated without any progress is preserved,
but now it does not result in an alert, since on an idle system event loop
iteration might be very short and EBUSY can happen many times in a row.
Instead, SF_NODISKIO is simply disabled for one call once the limit is
reached.
With this change, sendfile(SF_NODISKIO) is now used automatically as long as
sendfile() is enabled, and no longer requires "aio on;".
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 27 Dec 2021 19:48:33 +0300 |
parents | b45f052483b8 |
children |
line wrap: on
line source
/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> #define NGX_HTTP_LIMIT_CONN_PASSED 1 #define NGX_HTTP_LIMIT_CONN_REJECTED 2 #define NGX_HTTP_LIMIT_CONN_REJECTED_DRY_RUN 3 typedef struct { u_char color; u_char len; u_short conn; u_char data[1]; } ngx_http_limit_conn_node_t; typedef struct { ngx_shm_zone_t *shm_zone; ngx_rbtree_node_t *node; } ngx_http_limit_conn_cleanup_t; typedef struct { ngx_rbtree_t rbtree; ngx_rbtree_node_t sentinel; } ngx_http_limit_conn_shctx_t; typedef struct { ngx_http_limit_conn_shctx_t *sh; ngx_slab_pool_t *shpool; ngx_http_complex_value_t key; } ngx_http_limit_conn_ctx_t; typedef struct { ngx_shm_zone_t *shm_zone; ngx_uint_t conn; } ngx_http_limit_conn_limit_t; typedef struct { ngx_array_t limits; ngx_uint_t log_level; ngx_uint_t status_code; ngx_flag_t dry_run; } ngx_http_limit_conn_conf_t; static ngx_rbtree_node_t *ngx_http_limit_conn_lookup(ngx_rbtree_t *rbtree, ngx_str_t *key, uint32_t hash); static void ngx_http_limit_conn_cleanup(void *data); static ngx_inline void ngx_http_limit_conn_cleanup_all(ngx_pool_t *pool); static ngx_int_t ngx_http_limit_conn_status_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data); static void *ngx_http_limit_conn_create_conf(ngx_conf_t *cf); static char *ngx_http_limit_conn_merge_conf(ngx_conf_t *cf, void *parent, void *child); static char *ngx_http_limit_conn_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_conn_add_variables(ngx_conf_t *cf); static ngx_int_t ngx_http_limit_conn_init(ngx_conf_t *cf); static ngx_conf_enum_t ngx_http_limit_conn_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_conn_status_bounds = { ngx_conf_check_num_bounds, 400, 599 }; static ngx_command_t ngx_http_limit_conn_commands[] = { { ngx_string("limit_conn_zone"), NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE2, ngx_http_limit_conn_zone, 0, 0, NULL }, { ngx_string("limit_conn"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE2, ngx_http_limit_conn, NGX_HTTP_LOC_CONF_OFFSET, 0, NULL }, { ngx_string("limit_conn_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_conn_conf_t, log_level), &ngx_http_limit_conn_log_levels }, { ngx_string("limit_conn_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_conn_conf_t, status_code), &ngx_http_limit_conn_status_bounds }, { ngx_string("limit_conn_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_conn_conf_t, dry_run), NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_limit_conn_module_ctx = { ngx_http_limit_conn_add_variables, /* preconfiguration */ ngx_http_limit_conn_init, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_limit_conn_create_conf, /* create location configuration */ ngx_http_limit_conn_merge_conf /* merge location configuration */ }; ngx_module_t ngx_http_limit_conn_module = { NGX_MODULE_V1, &ngx_http_limit_conn_module_ctx, /* module context */ ngx_http_limit_conn_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_conn_vars[] = { { ngx_string("limit_conn_status"), NULL, ngx_http_limit_conn_status_variable, 0, NGX_HTTP_VAR_NOCACHEABLE, 0 }, ngx_http_null_variable }; static ngx_str_t ngx_http_limit_conn_status[] = { ngx_string("PASSED"), ngx_string("REJECTED"), ngx_string("REJECTED_DRY_RUN") }; static ngx_int_t ngx_http_limit_conn_handler(ngx_http_request_t *r) { size_t n; uint32_t hash; ngx_str_t key; ngx_uint_t i; ngx_rbtree_node_t *node; ngx_pool_cleanup_t *cln; ngx_http_limit_conn_ctx_t *ctx; ngx_http_limit_conn_node_t *lc; ngx_http_limit_conn_conf_t *lccf; ngx_http_limit_conn_limit_t *limits; ngx_http_limit_conn_cleanup_t *lccln; if (r->main->limit_conn_status) { return NGX_DECLINED; } lccf = ngx_http_get_module_loc_conf(r, ngx_http_limit_conn_module); limits = lccf->limits.elts; for (i = 0; i < lccf->limits.nelts; i++) { ctx = limits[i].shm_zone->data; if (ngx_http_complex_value(r, &ctx->key, &key) != NGX_OK) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } if (key.len == 0) { continue; } if (key.len > 255) { ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "the value of the \"%V\" key " "is more than 255 bytes: \"%V\"", &ctx->key.value, &key); continue; } r->main->limit_conn_status = NGX_HTTP_LIMIT_CONN_PASSED; hash = ngx_crc32_short(key.data, key.len); ngx_shmtx_lock(&ctx->shpool->mutex); node = ngx_http_limit_conn_lookup(&ctx->sh->rbtree, &key, hash); if (node == NULL) { n = offsetof(ngx_rbtree_node_t, color) + offsetof(ngx_http_limit_conn_node_t, data) + key.len; node = ngx_slab_alloc_locked(ctx->shpool, n); if (node == NULL) { ngx_shmtx_unlock(&ctx->shpool->mutex); ngx_http_limit_conn_cleanup_all(r->pool); if (lccf->dry_run) { r->main->limit_conn_status = NGX_HTTP_LIMIT_CONN_REJECTED_DRY_RUN; return NGX_DECLINED; } r->main->limit_conn_status = NGX_HTTP_LIMIT_CONN_REJECTED; return lccf->status_code; } lc = (ngx_http_limit_conn_node_t *) &node->color; node->key = hash; lc->len = (u_char) key.len; lc->conn = 1; ngx_memcpy(lc->data, key.data, key.len); ngx_rbtree_insert(&ctx->sh->rbtree, node); } else { lc = (ngx_http_limit_conn_node_t *) &node->color; if ((ngx_uint_t) lc->conn >= limits[i].conn) { ngx_shmtx_unlock(&ctx->shpool->mutex); ngx_log_error(lccf->log_level, r->connection->log, 0, "limiting connections%s by zone \"%V\"", lccf->dry_run ? ", dry run," : "", &limits[i].shm_zone->shm.name); ngx_http_limit_conn_cleanup_all(r->pool); if (lccf->dry_run) { r->main->limit_conn_status = NGX_HTTP_LIMIT_CONN_REJECTED_DRY_RUN; return NGX_DECLINED; } r->main->limit_conn_status = NGX_HTTP_LIMIT_CONN_REJECTED; return lccf->status_code; } lc->conn++; } ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "limit conn: %08Xi %d", node->key, lc->conn); ngx_shmtx_unlock(&ctx->shpool->mutex); cln = ngx_pool_cleanup_add(r->pool, sizeof(ngx_http_limit_conn_cleanup_t)); if (cln == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } cln->handler = ngx_http_limit_conn_cleanup; lccln = cln->data; lccln->shm_zone = limits[i].shm_zone; lccln->node = node; } return NGX_DECLINED; } static void ngx_http_limit_conn_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_conn_node_t *lcn, *lcnt; for ( ;; ) { if (node->key < temp->key) { p = &temp->left; } else if (node->key > temp->key) { p = &temp->right; } else { /* node->key == temp->key */ lcn = (ngx_http_limit_conn_node_t *) &node->color; lcnt = (ngx_http_limit_conn_node_t *) &temp->color; p = (ngx_memn2cmp(lcn->data, lcnt->data, lcn->len, lcnt->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_rbtree_node_t * ngx_http_limit_conn_lookup(ngx_rbtree_t *rbtree, ngx_str_t *key, uint32_t hash) { ngx_int_t rc; ngx_rbtree_node_t *node, *sentinel; ngx_http_limit_conn_node_t *lcn; node = rbtree->root; sentinel = rbtree->sentinel; while (node != sentinel) { if (hash < node->key) { node = node->left; continue; } if (hash > node->key) { node = node->right; continue; } /* hash == node->key */ lcn = (ngx_http_limit_conn_node_t *) &node->color; rc = ngx_memn2cmp(key->data, lcn->data, key->len, (size_t) lcn->len); if (rc == 0) { return node; } node = (rc < 0) ? node->left : node->right; } return NULL; } static void ngx_http_limit_conn_cleanup(void *data) { ngx_http_limit_conn_cleanup_t *lccln = data; ngx_rbtree_node_t *node; ngx_http_limit_conn_ctx_t *ctx; ngx_http_limit_conn_node_t *lc; ctx = lccln->shm_zone->data; node = lccln->node; lc = (ngx_http_limit_conn_node_t *) &node->color; ngx_shmtx_lock(&ctx->shpool->mutex); ngx_log_debug2(NGX_LOG_DEBUG_HTTP, lccln->shm_zone->shm.log, 0, "limit conn cleanup: %08Xi %d", node->key, lc->conn); lc->conn--; if (lc->conn == 0) { ngx_rbtree_delete(&ctx->sh->rbtree, node); ngx_slab_free_locked(ctx->shpool, node); } ngx_shmtx_unlock(&ctx->shpool->mutex); } static ngx_inline void ngx_http_limit_conn_cleanup_all(ngx_pool_t *pool) { ngx_pool_cleanup_t *cln; cln = pool->cleanup; while (cln && cln->handler == ngx_http_limit_conn_cleanup) { ngx_http_limit_conn_cleanup(cln->data); cln = cln->next; } pool->cleanup = cln; } static ngx_int_t ngx_http_limit_conn_init_zone(ngx_shm_zone_t *shm_zone, void *data) { ngx_http_limit_conn_ctx_t *octx = data; size_t len; ngx_http_limit_conn_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_conn_zone \"%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_conn_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_conn_rbtree_insert_value); len = sizeof(" in limit_conn_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_conn_zone \"%V\"%Z", &shm_zone->shm.name); return NGX_OK; } static ngx_int_t ngx_http_limit_conn_status_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data) { if (r->main->limit_conn_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_conn_status[r->main->limit_conn_status - 1].len; v->data = ngx_http_limit_conn_status[r->main->limit_conn_status - 1].data; return NGX_OK; } static void * ngx_http_limit_conn_create_conf(ngx_conf_t *cf) { ngx_http_limit_conn_conf_t *conf; conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_conn_conf_t)); if (conf == NULL) { return NULL; } /* * set by ngx_pcalloc(): * * conf->limits.elts = NULL; */ conf->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_conn_merge_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_http_limit_conn_conf_t *prev = parent; ngx_http_limit_conn_conf_t *conf = child; if (conf->limits.elts == NULL) { conf->limits = prev->limits; } ngx_conf_merge_uint_value(conf->log_level, prev->log_level, NGX_LOG_ERR); 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_conn_zone(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { u_char *p; ssize_t size; ngx_str_t *value, name, s; ngx_uint_t i; ngx_shm_zone_t *shm_zone; ngx_http_limit_conn_ctx_t *ctx; ngx_http_compile_complex_value_t ccv; value = cf->args->elts; ctx = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_conn_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; 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; } 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; } shm_zone = ngx_shared_memory_add(cf, &name, size, &ngx_http_limit_conn_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_conn_init_zone; shm_zone->data = ctx; return NGX_CONF_OK; } static char * ngx_http_limit_conn(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_shm_zone_t *shm_zone; ngx_http_limit_conn_conf_t *lccf = conf; ngx_http_limit_conn_limit_t *limit, *limits; ngx_str_t *value; ngx_int_t n; ngx_uint_t i; value = cf->args->elts; shm_zone = ngx_shared_memory_add(cf, &value[1], 0, &ngx_http_limit_conn_module); if (shm_zone == NULL) { return NGX_CONF_ERROR; } limits = lccf->limits.elts; if (limits == NULL) { if (ngx_array_init(&lccf->limits, cf->pool, 1, sizeof(ngx_http_limit_conn_limit_t)) != NGX_OK) { return NGX_CONF_ERROR; } } for (i = 0; i < lccf->limits.nelts; i++) { if (shm_zone == limits[i].shm_zone) { return "is duplicate"; } } n = ngx_atoi(value[2].data, value[2].len); if (n <= 0) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid number of connections \"%V\"", &value[2]); return NGX_CONF_ERROR; } if (n > 65535) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "connection limit must be less 65536"); return NGX_CONF_ERROR; } limit = ngx_array_push(&lccf->limits); if (limit == NULL) { return NGX_CONF_ERROR; } limit->conn = n; limit->shm_zone = shm_zone; return NGX_CONF_OK; } static ngx_int_t ngx_http_limit_conn_add_variables(ngx_conf_t *cf) { ngx_http_variable_t *var, *v; for (v = ngx_http_limit_conn_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_conn_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_conn_handler; return NGX_OK; }