/*
* Copyright (C) Igor Sysoev
* Copyright (C) Nginx, Inc.
*/
#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_stream.h>
#define NGX_STREAM_LIMIT_CONN_PASSED 1
#define NGX_STREAM_LIMIT_CONN_REJECTED 2
#define NGX_STREAM_LIMIT_CONN_REJECTED_DRY_RUN 3
typedef struct {
u_char color;
u_char len;
u_short conn;
u_char data[1];
} ngx_stream_limit_conn_node_t;
typedef struct {
ngx_shm_zone_t *shm_zone;
ngx_rbtree_node_t *node;
} ngx_stream_limit_conn_cleanup_t;
typedef struct {
ngx_rbtree_t rbtree;
ngx_rbtree_node_t sentinel;
} ngx_stream_limit_conn_shctx_t;
typedef struct {
ngx_stream_limit_conn_shctx_t *sh;
ngx_slab_pool_t *shpool;
ngx_stream_complex_value_t key;
} ngx_stream_limit_conn_ctx_t;
typedef struct {
ngx_shm_zone_t *shm_zone;
ngx_uint_t conn;
} ngx_stream_limit_conn_limit_t;
typedef struct {
ngx_array_t limits;
ngx_uint_t log_level;
ngx_flag_t dry_run;
} ngx_stream_limit_conn_conf_t;
static ngx_rbtree_node_t *ngx_stream_limit_conn_lookup(ngx_rbtree_t *rbtree,
ngx_str_t *key, uint32_t hash);
static void ngx_stream_limit_conn_cleanup(void *data);
static ngx_inline void ngx_stream_limit_conn_cleanup_all(ngx_pool_t *pool);
static ngx_int_t ngx_stream_limit_conn_status_variable(ngx_stream_session_t *s,
ngx_stream_variable_value_t *v, uintptr_t data);
static void *ngx_stream_limit_conn_create_conf(ngx_conf_t *cf);
static char *ngx_stream_limit_conn_merge_conf(ngx_conf_t *cf, void *parent,
void *child);
static char *ngx_stream_limit_conn_zone(ngx_conf_t *cf, ngx_command_t *cmd,
void *conf);
static char *ngx_stream_limit_conn(ngx_conf_t *cf, ngx_command_t *cmd,
void *conf);
static ngx_int_t ngx_stream_limit_conn_add_variables(ngx_conf_t *cf);
static ngx_int_t ngx_stream_limit_conn_init(ngx_conf_t *cf);
static ngx_conf_enum_t ngx_stream_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_command_t ngx_stream_limit_conn_commands[] = {
{ ngx_string("limit_conn_zone"),
NGX_STREAM_MAIN_CONF|NGX_CONF_TAKE2,
ngx_stream_limit_conn_zone,
0,
0,
NULL },
{ ngx_string("limit_conn"),
NGX_STREAM_MAIN_CONF|NGX_STREAM_SRV_CONF|NGX_CONF_TAKE2,
ngx_stream_limit_conn,
NGX_STREAM_SRV_CONF_OFFSET,
0,
NULL },
{ ngx_string("limit_conn_log_level"),
NGX_STREAM_MAIN_CONF|NGX_STREAM_SRV_CONF|NGX_CONF_TAKE1,
ngx_conf_set_enum_slot,
NGX_STREAM_SRV_CONF_OFFSET,
offsetof(ngx_stream_limit_conn_conf_t, log_level),
&ngx_stream_limit_conn_log_levels },
{ ngx_string("limit_conn_dry_run"),
NGX_STREAM_MAIN_CONF|NGX_STREAM_SRV_CONF|NGX_CONF_FLAG,
ngx_conf_set_flag_slot,
NGX_STREAM_SRV_CONF_OFFSET,
offsetof(ngx_stream_limit_conn_conf_t, dry_run),
NULL },
ngx_null_command
};
static ngx_stream_module_t ngx_stream_limit_conn_module_ctx = {
ngx_stream_limit_conn_add_variables, /* preconfiguration */
ngx_stream_limit_conn_init, /* postconfiguration */
NULL, /* create main configuration */
NULL, /* init main configuration */
ngx_stream_limit_conn_create_conf, /* create server configuration */
ngx_stream_limit_conn_merge_conf /* merge server configuration */
};
ngx_module_t ngx_stream_limit_conn_module = {
NGX_MODULE_V1,
&ngx_stream_limit_conn_module_ctx, /* module context */
ngx_stream_limit_conn_commands, /* module directives */
NGX_STREAM_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_stream_variable_t ngx_stream_limit_conn_vars[] = {
{ ngx_string("limit_conn_status"), NULL,
ngx_stream_limit_conn_status_variable, 0, NGX_STREAM_VAR_NOCACHEABLE, 0 },
ngx_stream_null_variable
};
static ngx_str_t ngx_stream_limit_conn_status[] = {
ngx_string("PASSED"),
ngx_string("REJECTED"),
ngx_string("REJECTED_DRY_RUN")
};
static ngx_int_t
ngx_stream_limit_conn_handler(ngx_stream_session_t *s)
{
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_stream_limit_conn_ctx_t *ctx;
ngx_stream_limit_conn_node_t *lc;
ngx_stream_limit_conn_conf_t *lccf;
ngx_stream_limit_conn_limit_t *limits;
ngx_stream_limit_conn_cleanup_t *lccln;
lccf = ngx_stream_get_module_srv_conf(s, ngx_stream_limit_conn_module);
limits = lccf->limits.elts;
for (i = 0; i < lccf->limits.nelts; i++) {
ctx = limits[i].shm_zone->data;
if (ngx_stream_complex_value(s, &ctx->key, &key) != NGX_OK) {
return NGX_ERROR;
}
if (key.len == 0) {
continue;
}
if (key.len > 255) {
ngx_log_error(NGX_LOG_ERR, s->connection->log, 0,
"the value of the \"%V\" key "
"is more than 255 bytes: \"%V\"",
&ctx->key.value, &key);
continue;
}
s->limit_conn_status = NGX_STREAM_LIMIT_CONN_PASSED;
hash = ngx_crc32_short(key.data, key.len);
ngx_shmtx_lock(&ctx->shpool->mutex);
node = ngx_stream_limit_conn_lookup(&ctx->sh->rbtree, &key, hash);
if (node == NULL) {
n = offsetof(ngx_rbtree_node_t, color)
+ offsetof(ngx_stream_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_stream_limit_conn_cleanup_all(s->connection->pool);
if (lccf->dry_run) {
s->limit_conn_status =
NGX_STREAM_LIMIT_CONN_REJECTED_DRY_RUN;
return NGX_DECLINED;
}
s->limit_conn_status = NGX_STREAM_LIMIT_CONN_REJECTED;
return NGX_STREAM_SERVICE_UNAVAILABLE;
}
lc = (ngx_stream_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_stream_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, s->connection->log, 0,
"limiting connections%s by zone \"%V\"",
lccf->dry_run ? ", dry run," : "",
&limits[i].shm_zone->shm.name);
ngx_stream_limit_conn_cleanup_all(s->connection->pool);
if (lccf->dry_run) {
s->limit_conn_status =
NGX_STREAM_LIMIT_CONN_REJECTED_DRY_RUN;
return NGX_DECLINED;
}
s->limit_conn_status = NGX_STREAM_LIMIT_CONN_REJECTED;
return NGX_STREAM_SERVICE_UNAVAILABLE;
}
lc->conn++;
}
ngx_log_debug2(NGX_LOG_DEBUG_STREAM, s->connection->log, 0,
"limit conn: %08Xi %d", node->key, lc->conn);
ngx_shmtx_unlock(&ctx->shpool->mutex);
cln = ngx_pool_cleanup_add(s->connection->pool,
sizeof(ngx_stream_limit_conn_cleanup_t));
if (cln == NULL) {
return NGX_ERROR;
}
cln->handler = ngx_stream_limit_conn_cleanup;
lccln = cln->data;
lccln->shm_zone = limits[i].shm_zone;
lccln->node = node;
}
return NGX_DECLINED;
}
static void
ngx_stream_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_stream_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_stream_limit_conn_node_t *) &node->color;
lcnt = (ngx_stream_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_stream_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_stream_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_stream_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_stream_limit_conn_cleanup(void *data)
{
ngx_stream_limit_conn_cleanup_t *lccln = data;
ngx_rbtree_node_t *node;
ngx_stream_limit_conn_ctx_t *ctx;
ngx_stream_limit_conn_node_t *lc;
ctx = lccln->shm_zone->data;
node = lccln->node;
lc = (ngx_stream_limit_conn_node_t *) &node->color;
ngx_shmtx_lock(&ctx->shpool->mutex);
ngx_log_debug2(NGX_LOG_DEBUG_STREAM, 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_stream_limit_conn_cleanup_all(ngx_pool_t *pool)
{
ngx_pool_cleanup_t *cln;
cln = pool->cleanup;
while (cln && cln->handler == ngx_stream_limit_conn_cleanup) {
ngx_stream_limit_conn_cleanup(cln->data);
cln = cln->next;
}
pool->cleanup = cln;
}
static ngx_int_t
ngx_stream_limit_conn_init_zone(ngx_shm_zone_t *shm_zone, void *data)
{
ngx_stream_limit_conn_ctx_t *octx = data;
size_t len;
ngx_stream_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_stream_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_stream_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_stream_limit_conn_status_variable(ngx_stream_session_t *s,
ngx_stream_variable_value_t *v, uintptr_t data)
{
if (s->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_stream_limit_conn_status[s->limit_conn_status - 1].len;
v->data = ngx_stream_limit_conn_status[s->limit_conn_status - 1].data;
return NGX_OK;
}
static void *
ngx_stream_limit_conn_create_conf(ngx_conf_t *cf)
{
ngx_stream_limit_conn_conf_t *conf;
conf = ngx_pcalloc(cf->pool, sizeof(ngx_stream_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->dry_run = NGX_CONF_UNSET;
return conf;
}
static char *
ngx_stream_limit_conn_merge_conf(ngx_conf_t *cf, void *parent, void *child)
{
ngx_stream_limit_conn_conf_t *prev = parent;
ngx_stream_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_value(conf->dry_run, prev->dry_run, 0);
return NGX_CONF_OK;
}
static char *
ngx_stream_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_stream_limit_conn_ctx_t *ctx;
ngx_stream_compile_complex_value_t ccv;
value = cf->args->elts;
ctx = ngx_pcalloc(cf->pool, sizeof(ngx_stream_limit_conn_ctx_t));
if (ctx == NULL) {
return NGX_CONF_ERROR;
}
ngx_memzero(&ccv, sizeof(ngx_stream_compile_complex_value_t));
ccv.cf = cf;
ccv.value = &value[1];
ccv.complex_value = &ctx->key;
if (ngx_stream_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_stream_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_stream_limit_conn_init_zone;
shm_zone->data = ctx;
return NGX_CONF_OK;
}
static char *
ngx_stream_limit_conn(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
ngx_shm_zone_t *shm_zone;
ngx_stream_limit_conn_conf_t *lccf = conf;
ngx_stream_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_stream_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_stream_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_stream_limit_conn_add_variables(ngx_conf_t *cf)
{
ngx_stream_variable_t *var, *v;
for (v = ngx_stream_limit_conn_vars; v->name.len; v++) {
var = ngx_stream_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_stream_limit_conn_init(ngx_conf_t *cf)
{
ngx_stream_handler_pt *h;
ngx_stream_core_main_conf_t *cmcf;
cmcf = ngx_stream_conf_get_module_main_conf(cf, ngx_stream_core_module);
h = ngx_array_push(&cmcf->phases[NGX_STREAM_PREACCESS_PHASE].handlers);
if (h == NULL) {
return NGX_ERROR;
}
*h = ngx_stream_limit_conn_handler;
return NGX_OK;
}
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