// 在ngx_stream_optimize_servers里设置有连接发生时的回调函数
// 调用发生在ngx_event_accept.c:ngx_event_accept()
//
// 创建一个处理tcp的会话对象
// 要先检查限速和访问限制这两个功能模块
// 最后调用ngx_stream_init_session
// 创建ctx数组，用于存储模块的ctx数据
// 调用handler，处理tcp数据，收发等等
void
ngx_stream_init_connection(ngx_connection_t *c)
{
int tcp_nodelay;
u_char text[NGX_SOCKADDR_STRLEN];
size_t len;
ngx_int_t rc;
ngx_uint_t i;
struct sockaddr *sa;
ngx_stream_port_t *port;
struct sockaddr_in *sin;
ngx_stream_in_addr_t *addr;
ngx_stream_session_t *s;
ngx_stream_addr_conf_t *addr_conf;
#if (NGX_HAVE_INET6)
struct sockaddr_in6 *sin6;
ngx_stream_in6_addr_t *addr6;
#endif
ngx_stream_core_srv_conf_t *cscf;
ngx_stream_core_main_conf_t *cmcf;
/* find the server configuration for the address:port */
// 取监听同一端口的server信息
port = c->listening->servers;
if (port->naddrs > 1) {
/*
* There are several addresses on this port and one of them
* is the "*:port" wildcard so getsockname() is needed to determine
* the server address.
*
* AcceptEx() already gave this address.
*/
if (ngx_connection_local_sockaddr(c, NULL, 0) != NGX_OK) {
ngx_stream_close_connection(c);
return;
}
sa = c->local_sockaddr;
switch (sa->sa_family) {
#if (NGX_HAVE_INET6)
case AF_INET6:
sin6 = (struct sockaddr_in6 *) sa;
addr6 = port->addrs;
/* the last address is "*" */
for (i = 0; i < port->naddrs - 1; i++) {
if (ngx_memcmp(&addr6[i].addr6, &sin6->sin6_addr, 16) == 0) {
break;
}
}
addr_conf = &addr6[i].conf;
break;
#endif
default: /* AF_INET */
sin = (struct sockaddr_in *) sa;
addr = port->addrs;
/* the last address is "*" */
for (i = 0; i < port->naddrs - 1; i++) {
if (addr[i].addr == sin->sin_addr.s_addr) {
break;
}
}
addr_conf = &addr[i].conf;
break;
}
} else {
// 唯一监听端口的server
// addr_conf就是端口所在的server的配置数组
switch (c->local_sockaddr->sa_family) {
#if (NGX_HAVE_INET6)
case AF_INET6:
addr6 = port->addrs;
addr_conf = &addr6[0].conf;
break;
#endif
default: /* AF_INET */
addr = port->addrs;
addr_conf = &addr[0].conf;
break;
}
}
// 创建一个处理tcp的会话对象
s = ngx_pcalloc(c->pool, sizeof(ngx_stream_session_t));
if (s == NULL) {
ngx_stream_close_connection(c);
return;
}
// 设置会话对象的标志
s->signature = NGX_STREAM_MODULE;
//设置会话正确的配置结构体
// addr_conf就是端口所在的server的配置数组
// 之后就可以用宏正确地获取模块的配置信息
s->main_conf = addr_conf->ctx->main_conf;
s->srv_conf = addr_conf->ctx->srv_conf;
// 设置会话关联的连接对象
s->connection = c;
// 连接的data指针指向会话对象
c->data = s;
// 获取相关的core配置
cscf = ngx_stream_get_module_srv_conf(s, ngx_stream_core_module);
ngx_set_connection_log(c, cscf->error_log);
len = ngx_sock_ntop(c->sockaddr, c->socklen, text, NGX_SOCKADDR_STRLEN, 1);
ngx_log_error(NGX_LOG_INFO, c->log, 0, "*%uA client %*s connected to %V",
c->number, len, text, &addr_conf->addr_text);
// log的一些参数
c->log->connection = c->number;
c->log->handler = ngx_stream_log_error;
c->log->data = s;
c->log->action = "initializing connection";
c->log_error = NGX_ERROR_INFO;
// 一个stream{}块只能有一个main conf
// 所以连接限速、访问限制的处理函数是相同的
// 但配置参数每个server可以不同
cmcf = ngx_stream_get_module_main_conf(s, ngx_stream_core_module);
// 是否有连接限速设置，在ngx_stream_limit_conn_module.c里设置
if (cmcf->limit_conn_handler) {
rc = cmcf->limit_conn_handler(s);
if (rc != NGX_DECLINED) {
ngx_stream_close_connection(c);
return;
}
}
// 是否有访问限制
if (cmcf->access_handler) {
rc = cmcf->access_handler(s);
if (rc != NGX_OK && rc != NGX_DECLINED) {
ngx_stream_close_connection(c);
return;
}
}
// 设置TCP_NODELAY，默认启用
if (cscf->tcp_nodelay && c->tcp_nodelay == NGX_TCP_NODELAY_UNSET) {
ngx_log_debug0(NGX_LOG_DEBUG_STREAM, c->log, 0, "tcp_nodelay");
tcp_nodelay = 1;
if (setsockopt(c->fd, IPPROTO_TCP, TCP_NODELAY,
(const void *) &tcp_nodelay, sizeof(int)) == -1)
{
ngx_connection_error(c, ngx_socket_errno,
"setsockopt(TCP_NODELAY) failed");
ngx_stream_close_connection(c);
return;
}
c->tcp_nodelay = NGX_TCP_NODELAY_SET;
}
#if (NGX_STREAM_SSL)
{
ngx_stream_ssl_conf_t *sslcf;
sslcf = ngx_stream_get_module_srv_conf(s, ngx_stream_ssl_module);
if (addr_conf->ssl) {
c->log->action = "SSL handshaking";
if (sslcf->ssl.ctx == NULL) {
ngx_log_error(NGX_LOG_ERR, c->log, 0,
"no \"ssl_certificate\" is defined "
"in server listening on SSL port");
ngx_stream_close_connection(c);
return;
}
ngx_stream_ssl_init_connection(&sslcf->ssl, c);
return;
}
}
#endif
// 创建ctx数组，用于存储模块的ctx数据
// 调用handler，处理tcp数据，收发等等
ngx_stream_init_session(c);
}
void
ngx_stream_init_connection(ngx_connection_t *c)
{
u_char text[NGX_SOCKADDR_STRLEN];
size_t len;
ngx_int_t rc;
ngx_uint_t i;
struct sockaddr *sa;
ngx_stream_port_t *port;
struct sockaddr_in *sin;
ngx_stream_in_addr_t *addr;
ngx_stream_session_t *s;
ngx_stream_addr_conf_t *addr_conf;
#if (NGX_HAVE_INET6)
struct sockaddr_in6 *sin6;
ngx_stream_in6_addr_t *addr6;
#endif
ngx_stream_core_srv_conf_t *cscf;
ngx_stream_core_main_conf_t *cmcf;
/* find the server configuration for the address:port */
port = c->listening->servers;
if (port->naddrs > 1) {
/*
* There are several addresses on this port and one of them
* is the "*:port" wildcard so getsockname() is needed to determine
* the server address.
*
* AcceptEx() already gave this address.
*/
if (ngx_connection_local_sockaddr(c, NULL, 0) != NGX_OK) {
ngx_stream_close_connection(c);
return;
}
sa = c->local_sockaddr;
switch (sa->sa_family) {
#if (NGX_HAVE_INET6)
case AF_INET6:
sin6 = (struct sockaddr_in6 *) sa;
addr6 = port->addrs;
/* the last address is "*" */
for (i = 0; i < port->naddrs - 1; i++) {
if (ngx_memcmp(&addr6[i].addr6, &sin6->sin6_addr, 16) == 0) {
break;
}
}
addr_conf = &addr6[i].conf;
break;
#endif
default: /* AF_INET */
sin = (struct sockaddr_in *) sa;
addr = port->addrs;
/* the last address is "*" */
for (i = 0; i < port->naddrs - 1; i++) {
if (addr[i].addr == sin->sin_addr.s_addr) {
break;
}
}
addr_conf = &addr[i].conf;
break;
}
} else {
switch (c->local_sockaddr->sa_family) {
#if (NGX_HAVE_INET6)
case AF_INET6:
addr6 = port->addrs;
addr_conf = &addr6[0].conf;
break;
#endif
default: /* AF_INET */
addr = port->addrs;
addr_conf = &addr[0].conf;
break;
}
}
s = ngx_pcalloc(c->pool, sizeof(ngx_stream_session_t));
if (s == NULL) {
ngx_stream_close_connection(c);
return;
}
s->signature = NGX_STREAM_MODULE;
s->main_conf = addr_conf->ctx->main_conf;
s->srv_conf = addr_conf->ctx->srv_conf;
s->connection = c;
c->data = s;
cscf = ngx_stream_get_module_srv_conf(s, ngx_stream_core_module);
ngx_set_connection_log(c, cscf->error_log);
len = ngx_sock_ntop(c->sockaddr, c->socklen, text, NGX_SOCKADDR_STRLEN, 1);
ngx_log_error(NGX_LOG_INFO, c->log, 0, "*%uA client %*s connected to %V",
c->number, len, text, &addr_conf->addr_text);
c->log->connection = c->number;
c->log->handler = ngx_stream_log_error;
c->log->data = s;
c->log->action = "initializing connection";
c->log_error = NGX_ERROR_INFO;
cmcf = ngx_stream_get_module_main_conf(s, ngx_stream_core_module);
if (cmcf->access_handler) {
rc = cmcf->access_handler(s);
if (rc != NGX_OK && rc != NGX_DECLINED) {
ngx_stream_close_connection(c);
return;
}
}
#if (NGX_STREAM_SSL)
{
ngx_stream_ssl_conf_t *sslcf;
sslcf = ngx_stream_get_module_srv_conf(s, ngx_stream_ssl_module);
if (addr_conf->ssl) {
c->log->action = "SSL handshaking";
if (sslcf->ssl.ctx == NULL) {
ngx_log_error(NGX_LOG_ERR, c->log, 0,
"no \"ssl_certificate\" is defined "
"in server listening on SSL port");
ngx_stream_close_connection(c);
return;
}
ngx_stream_ssl_init_connection(&sslcf->ssl, c);
return;
}
}
#endif
ngx_stream_init_session(c);
}
static void
ngx_http_lua_timer_handler(ngx_event_t *ev)
{
int n;
lua_State *L;
ngx_int_t rc;
ngx_connection_t *c = NULL;
ngx_http_request_t *r = NULL;
ngx_http_lua_ctx_t *ctx;
ngx_http_cleanup_t *cln;
ngx_pool_cleanup_t *pcln;
ngx_http_lua_timer_ctx_t tctx;
ngx_http_lua_main_conf_t *lmcf;
ngx_http_core_loc_conf_t *clcf;
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, ngx_cycle->log, 0,
"lua ngx.timer expired");
ngx_memcpy(&tctx, ev->data, sizeof(ngx_http_lua_timer_ctx_t));
ngx_free(ev);
ev = NULL;
lmcf = tctx.lmcf;
lmcf->pending_timers--;
if (lmcf->running_timers >= lmcf->max_running_timers) {
ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0,
"%i lua_max_running_timers are not enough",
lmcf->max_running_timers);
goto failed;
}
c = ngx_http_lua_create_fake_connection(tctx.pool);
if (c == NULL) {
goto failed;
}
c->log->handler = ngx_http_lua_log_timer_error;
c->log->data = c;
c->listening = tctx.listening;
c->addr_text = tctx.client_addr_text;
r = ngx_http_lua_create_fake_request(c);
if (r == NULL) {
goto failed;
}
r->main_conf = tctx.main_conf;
r->srv_conf = tctx.srv_conf;
r->loc_conf = tctx.loc_conf;
clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
#if defined(nginx_version) && nginx_version >= 1003014
# if nginx_version >= 1009000
ngx_set_connection_log(r->connection, clcf->error_log);
# else
ngx_http_set_connection_log(r->connection, clcf->error_log);
# endif
#else
c->log->file = clcf->error_log->file;
if (!(c->log->log_level & NGX_LOG_DEBUG_CONNECTION)) {
c->log->log_level = clcf->error_log->log_level;
}
#endif
dd("lmcf: %p", lmcf);
ctx = ngx_http_lua_create_ctx(r);
if (ctx == NULL) {
goto failed;
}
if (tctx.vm_state) {
ctx->vm_state = tctx.vm_state;
pcln = ngx_pool_cleanup_add(r->pool, 0);
if (pcln == NULL) {
goto failed;
}
pcln->handler = ngx_http_lua_cleanup_vm;
pcln->data = tctx.vm_state;
}
ctx->cur_co_ctx = &ctx->entry_co_ctx;
L = ngx_http_lua_get_lua_vm(r, ctx);
cln = ngx_http_cleanup_add(r, 0);
if (cln == NULL) {
goto failed;
}
cln->handler = ngx_http_lua_request_cleanup_handler;
cln->data = ctx;
ctx->cleanup = &cln->handler;
ctx->entered_content_phase = 1;
ctx->context = NGX_HTTP_LUA_CONTEXT_TIMER;
r->read_event_handler = ngx_http_block_reading;
ctx->cur_co_ctx->co_ref = tctx.co_ref;
ctx->cur_co_ctx->co = tctx.co;
ctx->cur_co_ctx->co_status = NGX_HTTP_LUA_CO_RUNNING;
dd("r connection: %p, log %p", r->connection, r->connection->log);
/* save the request in coroutine globals table */
ngx_http_lua_set_req(tctx.co, r);
lmcf->running_timers++;
lua_pushboolean(tctx.co, tctx.premature);
n = lua_gettop(tctx.co);
if (n > 2) {
lua_insert(tctx.co, 2);
}
#ifdef NGX_LUA_USE_ASSERT
ctx->cur_co_ctx->co_top = 1;
#endif
rc = ngx_http_lua_run_thread(L, r, ctx, n - 1);
dd("timer lua run thread: %d", (int) rc);
if (rc == NGX_ERROR || rc >= NGX_OK) {
/* do nothing */
} else if (rc == NGX_AGAIN) {
rc = ngx_http_lua_content_run_posted_threads(L, r, ctx, 0);
} else if (rc == NGX_DONE) {
rc = ngx_http_lua_content_run_posted_threads(L, r, ctx, 1);
} else {
rc = NGX_OK;
}
ngx_http_lua_finalize_request(r, rc);
return;
failed:
if (tctx.co_ref && tctx.co) {
lua_pushlightuserdata(tctx.co, &ngx_http_lua_coroutines_key);
lua_rawget(tctx.co, LUA_REGISTRYINDEX);
luaL_unref(tctx.co, -1, tctx.co_ref);
lua_settop(tctx.co, 0);
}
if (tctx.vm_state) {
ngx_http_lua_cleanup_vm(tctx.vm_state);
}
if (c) {
ngx_http_lua_close_fake_connection(c);
} else if (tctx.pool) {
ngx_destroy_pool(tctx.pool);
}
}
/* callback for new session caching, to be set with SSL_CTX_sess_set_new_cb */
int
ngx_http_lua_ssl_sess_store_handler(ngx_ssl_conn_t *ssl_conn,
ngx_ssl_session_t *sess)
{
lua_State *L;
ngx_int_t rc;
#if OPENSSL_VERSION_NUMBER >= 0x1010005fL
unsigned int len;
#endif
ngx_connection_t *c, *fc = NULL;
ngx_http_request_t *r = NULL;
ngx_http_connection_t *hc;
ngx_http_lua_ssl_ctx_t *cctx;
ngx_http_lua_srv_conf_t *lscf;
ngx_http_core_loc_conf_t *clcf;
c = ngx_ssl_get_connection(ssl_conn);
dd("c = %p", c);
cctx = ngx_http_lua_ssl_get_ctx(c->ssl->connection);
dd("ssl sess_store handler, sess_store-ctx=%p", cctx);
hc = c->data;
fc = ngx_http_lua_create_fake_connection(NULL);
if (fc == NULL) {
goto failed;
}
fc->log->handler = ngx_http_lua_log_ssl_sess_store_error;
fc->log->data = fc;
fc->addr_text = c->addr_text;
fc->listening = c->listening;
r = ngx_http_lua_create_fake_request(fc);
if (r == NULL) {
goto failed;
}
r->main_conf = hc->conf_ctx->main_conf;
r->srv_conf = hc->conf_ctx->srv_conf;
r->loc_conf = hc->conf_ctx->loc_conf;
fc->log->file = c->log->file;
fc->log->log_level = c->log->log_level;
fc->ssl = c->ssl;
clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
#if defined(nginx_version) && nginx_version >= 1003014
# if nginx_version >= 1009000
ngx_set_connection_log(fc, clcf->error_log);
# else
ngx_http_set_connection_log(fc, clcf->error_log);
# endif
#else
fc->log->file = clcf->error_log->file;
if (!(fc->log->log_level & NGX_LOG_DEBUG_CONNECTION)) {
fc->log->log_level = clcf->error_log->log_level;
}
#endif
if (cctx == NULL) {
cctx = ngx_pcalloc(c->pool, sizeof(ngx_http_lua_ssl_ctx_t));
if (cctx == NULL) {
goto failed; /* error */
}
}
cctx->connection = c;
cctx->request = r;
cctx->session = sess;
#if OPENSSL_VERSION_NUMBER < 0x1010005fL
cctx->session_id.data = sess->session_id;
cctx->session_id.len = sess->session_id_length;
#else
cctx->session_id.data = (u_char *)SSL_SESSION_get_id(sess, &len);
cctx->session_id.len = len;
#endif
cctx->done = 0;
dd("setting cctx");
if (SSL_set_ex_data(c->ssl->connection, ngx_http_lua_ssl_ctx_index, cctx)
== 0)
{
ngx_ssl_error(NGX_LOG_ALERT, c->log, 0, "SSL_set_ex_data() failed");
goto failed;
}
lscf = ngx_http_get_module_srv_conf(r, ngx_http_lua_module);
/* TODO honor lua_code_cache off */
L = ngx_http_lua_get_lua_vm(r, NULL);
c->log->action = "storing SSL session by lua";
rc = lscf->srv.ssl_sess_store_handler(r, lscf, L);
if (rc >= NGX_OK || rc == NGX_ERROR) {
cctx->done = 1;
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
"ssl_session_store_by_lua*: handler return value: %i, "
"sess new cb exit code: %d", rc, cctx->exit_code);
c->log->action = "SSL handshaking";
/* Return value is a flag indicating whether the passed-in session
* has been freed by this callback; always return 0 so OpenSSL will
* free the session. Nginx's own session caching logic has the same
* practice. */
return 0;
}
/* impossible to reach here */
ngx_http_lua_assert(0);
failed:
if (r && r->pool) {
ngx_http_lua_free_fake_request(r);
}
if (fc) {
ngx_http_lua_close_fake_connection(fc);
}
return 0;
}
/* cached session fetching callback to be set with SSL_CTX_sess_set_get_cb */
ngx_ssl_session_t *
ngx_http_lua_ssl_sess_fetch_handler(ngx_ssl_conn_t *ssl_conn, u_char *id,
int len, int *copy)
{
lua_State *L;
ngx_int_t rc;
ngx_connection_t *c, *fc = NULL;
ngx_http_request_t *r = NULL;
ngx_pool_cleanup_t *cln;
ngx_http_connection_t *hc;
ngx_http_lua_ssl_ctx_t *cctx;
ngx_http_lua_srv_conf_t *lscf;
ngx_http_core_loc_conf_t *clcf;
/* set copy to 0 as we expect OpenSSL to handle
* the memory of returned session */
*copy = 0;
c = ngx_ssl_get_connection(ssl_conn);
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
"ssl session fetch: connection reusable: %ud", c->reusable);
cctx = ngx_http_lua_ssl_get_ctx(c->ssl->connection);
dd("ssl sess_fetch handler, sess_fetch-ctx=%p", cctx);
if (cctx && cctx->entered_sess_fetch_handler) {
/* not the first time */
dd("here: %d", (int) cctx->entered_sess_fetch_handler);
if (cctx->done) {
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
"ssl_session_fetch_by_lua*: "
"sess get cb exit code: %d",
cctx->exit_code);
dd("lua ssl sess_fetch done, finally");
return cctx->session;
}
#ifdef SSL_ERROR_PENDING_SESSION
return SSL_magic_pending_session_ptr();
#else
ngx_log_error(NGX_LOG_CRIT, c->log, 0,
"lua: cannot yield in sess get cb: "
"missing async sess get cb support in OpenSSL");
return NULL;
#endif
}
dd("first time");
ngx_reusable_connection(c, 0);
hc = c->data;
fc = ngx_http_lua_create_fake_connection(NULL);
if (fc == NULL) {
goto failed;
}
fc->log->handler = ngx_http_lua_log_ssl_sess_fetch_error;
fc->log->data = fc;
fc->addr_text = c->addr_text;
fc->listening = c->listening;
r = ngx_http_lua_create_fake_request(fc);
if (r == NULL) {
goto failed;
}
r->main_conf = hc->conf_ctx->main_conf;
r->srv_conf = hc->conf_ctx->srv_conf;
r->loc_conf = hc->conf_ctx->loc_conf;
fc->log->file = c->log->file;
fc->log->log_level = c->log->log_level;
fc->ssl = c->ssl;
clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
#if defined(nginx_version) && nginx_version >= 1003014
# if nginx_version >= 1009000
ngx_set_connection_log(fc, clcf->error_log);
# else
ngx_http_set_connection_log(fc, clcf->error_log);
# endif
#else
fc->log->file = clcf->error_log->file;
if (!(fc->log->log_level & NGX_LOG_DEBUG_CONNECTION)) {
fc->log->log_level = clcf->error_log->log_level;
}
#endif
if (cctx == NULL) {
cctx = ngx_pcalloc(c->pool, sizeof(ngx_http_lua_ssl_ctx_t));
if (cctx == NULL) {
goto failed; /* error */
}
}
cctx->exit_code = 1; /* successful by default */
cctx->connection = c;
cctx->request = r;
cctx->session_id.data = id;
cctx->session_id.len = len;
cctx->entered_sess_fetch_handler = 1;
cctx->done = 0;
dd("setting cctx = %p", cctx);
if (SSL_set_ex_data(c->ssl->connection, ngx_http_lua_ssl_ctx_index, cctx)
== 0)
{
ngx_ssl_error(NGX_LOG_ALERT, c->log, 0, "SSL_set_ex_data() failed");
goto failed;
}
lscf = ngx_http_get_module_srv_conf(r, ngx_http_lua_module);
/* TODO honor lua_code_cache off */
L = ngx_http_lua_get_lua_vm(r, NULL);
c->log->action = "fetching SSL session by lua";
rc = lscf->srv.ssl_sess_fetch_handler(r, lscf, L);
if (rc >= NGX_OK || rc == NGX_ERROR) {
cctx->done = 1;
if (cctx->cleanup) {
*cctx->cleanup = NULL;
}
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
"ssl_session_fetch_by_lua*: handler return value: %i, "
"sess get cb exit code: %d", rc, cctx->exit_code);
c->log->action = "SSL handshaking";
return cctx->session;
}
/* rc == NGX_DONE */
cln = ngx_pool_cleanup_add(fc->pool, 0);
if (cln == NULL) {
goto failed;
}
cln->handler = ngx_http_lua_ssl_sess_fetch_done;
cln->data = cctx;
if (cctx->cleanup == NULL) {
/* we only want exactly one cleanup handler to be registered with the
* connection to clean up cctx when connection is aborted */
cln = ngx_pool_cleanup_add(c->pool, 0);
if (cln == NULL) {
goto failed;
}
cln->data = cctx;
cctx->cleanup = &cln->handler;
}
*cctx->cleanup = ngx_http_lua_ssl_sess_fetch_aborted;
#ifdef SSL_ERROR_PENDING_SESSION
return SSL_magic_pending_session_ptr();
#else
ngx_log_error(NGX_LOG_CRIT, c->log, 0,
"lua: cannot yield in sess get cb: "
"missing async sess get cb support in OpenSSL");
/* fall through to the "failed" label below */
#endif
failed:
if (r && r->pool) {
ngx_http_lua_free_fake_request(r);
}
if (fc) {
ngx_http_lua_close_fake_connection(fc);
}
return NULL;
}