Adding upstream version 3.8.1.upstream/3.8.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2566 insertions, 0 deletions

diff --git a/src/lua/lua_tcp.c b/src/lua/lua_tcp.c
new file mode 100644
index 0000000..45faa79
--- /dev/null
+++ b/src/lua/lua_tcp.c
@@ -0,0 +1,2566 @@
+/*-
+ * Copyright 2016 Vsevolod Stakhov
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "lua_common.h"
+#include "lua_thread_pool.h"
+#include "libserver/ssl_util.h"
+#include "utlist.h"
+#include "unix-std.h"
+#include <math.h>
+
+static const gchar *M = "rspamd lua tcp";
+
+/***
+ * @module rspamd_tcp
+ * Rspamd TCP module represents generic TCP asynchronous client available from LUA code.
+ * This module hides all complexity: DNS resolving, sessions management, zero-copy
+ * text transfers and so on under the hood. It can work in partial or complete modes:
+ *
+ * - partial mode is used when you need to call a continuation routine each time data is available for read
+ * - complete mode calls for continuation merely when all data is read from socket (e.g. when a server sends reply and closes a connection)
+ * @example
+local logger = require "rspamd_logger"
+local tcp = require "rspamd_tcp"
+
+rspamd_config.SYM = function(task)
+
+    local function cb(err, data)
+        logger.infox('err: %1, data: %2', err, tostring(data))
+    end
+
+    tcp.request({
+    	task = task,
+    	host = "google.com",
+    	port = 80,
+    	data = {"GET / HTTP/1.0\r\n", "Host: google.com\r\n", "\r\n"},
+    	callback = cb})
+end
+
+-- New TCP syntax test
+rspamd_config:register_symbol({
+  name = 'TCP_TEST',
+  type = "normal",
+  callback = function(task)
+    local logger = require "rspamd_logger"
+    local function rcpt_done_cb(err, data, conn)
+      logger.errx(task, 'RCPT: got reply: %s, error: %s', data, err)
+      conn:close()
+    end
+    local function rcpt_cb(err, conn)
+      logger.errx(task, 'written rcpt, error: %s', err)
+      conn:add_read(rcpt_done_cb, '\r\n')
+    end
+    local function from_done_cb(err, data, conn)
+      logger.errx(task, 'FROM: got reply: %s, error: %s', data, err)
+      conn:add_write(rcpt_cb, 'RCPT TO: <test@yandex.ru>\r\n')
+    end
+    local function from_cb(err, conn)
+      logger.errx(task, 'written from, error: %s', err)
+      conn:add_read(from_done_cb, '\r\n')
+    end
+    local function hello_done_cb(err, data, conn)
+      logger.errx(task, 'HELO: got reply: %s, error: %s', data, err)
+      conn:add_write(from_cb, 'MAIL FROM: <>\r\n')
+    end
+    local function hello_cb(err, conn)
+      logger.errx(task, 'written hello, error: %s', err)
+      conn:add_read(hello_done_cb, '\r\n')
+    end
+    local function init_cb(err, data, conn)
+      logger.errx(task, 'got reply: %s, error: %s', data, err)
+      conn:add_write(hello_cb, 'HELO example.com\r\n')
+    end
+    tcp.request{
+      task = task,
+      callback = init_cb,
+      stop_pattern = '\r\n',
+      host = 'mx.yandex.ru',
+      port = 25
+    }
+  end,
+  priority = 10,
+})
+ */
+
+LUA_FUNCTION_DEF(tcp, request);
+
+/***
+ * @function rspamd_tcp.connect_sync()
+ *
+ * Creates pseudo-synchronous TCP connection.
+ * Each method of the connection requiring IO, becomes a yielding point,
+ * i.e. current thread Lua thread is get suspended and resumes as soon as IO is done
+ *
+ * This class represents low-level API, using of "lua_tcp_sync" module is recommended.
+ *
+ * @example
+
+local rspamd_tcp = require "rspamd_tcp"
+local logger = require "rspamd_logger"
+
+local function http_simple_tcp_symbol(task)
+
+    local err
+    local is_ok, connection = rspamd_tcp.connect_sync {
+      task = task,
+      host = '127.0.0.1',
+      timeout = 20,
+      port = 18080,
+      ssl = false, -- If SSL connection is needed
+      ssl_verify = true, -- set to false if verify is not needed
+    }
+
+    is_ok, err = connection:write('GET /request_sync HTTP/1.1\r\nConnection: keep-alive\r\n\r\n')
+
+    logger.errx(task, 'write %1, %2', is_ok, err)
+    if not is_ok then
+      logger.errx(task, 'write error: %1', err)
+    end
+
+    local data
+    is_ok, data = connection:read_once();
+
+    logger.errx(task, 'read_once: is_ok: %1, data: %2', is_ok, data)
+
+    is_ok, err = connection:write("POST /request2 HTTP/1.1\r\n\r\n")
+    logger.errx(task, 'write[2] %1, %2', is_ok, err)
+
+    is_ok, data = connection:read_once();
+    logger.errx(task, 'read_once[2]: is_ok %1, data: %2', is_ok, data)
+
+    connection:close()
+end
+
+rspamd_config:register_symbol({
+  name = 'SIMPLE_TCP_TEST',
+  score = 1.0,
+  callback = http_simple_tcp_symbol,
+  no_squeeze = true
+})
+ *
+ */
+LUA_FUNCTION_DEF(tcp, connect_sync);
+
+/***
+ * @method tcp:close()
+ *
+ * Closes TCP connection
+ */
+LUA_FUNCTION_DEF(tcp, close);
+
+/***
+ * @method tcp:add_read(callback, [pattern])
+ *
+ * Adds new read event to the tcp connection
+ * @param {function} callback to be called when data is read
+ * @param {string} pattern optional stop pattern
+ */
+LUA_FUNCTION_DEF(tcp, add_read);
+
+/***
+ * @method tcp:add_write(callback, data)
+ *
+ * Adds new write event to the tcp connection
+ * @param {function} optional callback to be called when data is completely written
+ * @param {table/string/text} data to send to a remote server
+ */
+LUA_FUNCTION_DEF(tcp, add_write);
+
+/***
+ * @method tcp:shift_callback()
+ *
+ * Shifts the current callback and go to the next one (if any)
+ */
+LUA_FUNCTION_DEF(tcp, shift_callback);
+
+/***
+ * @method tcp:starttls([no_verify])
+ *
+ * Starts tls connection
+ * @param {boolean} no_verify used to skip ssl verification
+ */
+LUA_FUNCTION_DEF(tcp, starttls);
+
+static const struct luaL_reg tcp_libf[] = {
+	LUA_INTERFACE_DEF(tcp, request),
+	{"new", lua_tcp_request},
+	{"connect", lua_tcp_request},
+	{"connect_sync", lua_tcp_connect_sync},
+	{NULL, NULL}};
+
+static const struct luaL_reg tcp_libm[] = {
+	LUA_INTERFACE_DEF(tcp, close),
+	LUA_INTERFACE_DEF(tcp, add_read),
+	LUA_INTERFACE_DEF(tcp, add_write),
+	LUA_INTERFACE_DEF(tcp, shift_callback),
+	LUA_INTERFACE_DEF(tcp, starttls),
+	{"__tostring", rspamd_lua_class_tostring},
+	{NULL, NULL}};
+
+/***
+ * @method tcp:close()
+ *
+ * Closes TCP connection
+ */
+LUA_FUNCTION_DEF(tcp_sync, close);
+
+/***
+ * @method read_once()
+ *
+ * Performs one read operation. If syscall returned with EAGAIN/EINT,
+ * restarts the operation, so it always returns either data or error.
+ */
+LUA_FUNCTION_DEF(tcp_sync, read_once);
+
+/***
+ * @method eof()
+ *
+ * True if last IO operation ended with EOF, i.e. endpoint closed connection
+ */
+LUA_FUNCTION_DEF(tcp_sync, eof);
+
+/***
+ * @method shutdown()
+ *
+ * Half-shutdown TCP connection
+ */
+LUA_FUNCTION_DEF(tcp_sync, shutdown);
+
+/***
+ * @method write()
+ *
+ * Writes data into the stream. If syscall returned with EAGAIN/EINT
+ * restarts the operation. If performs write() until all the passed
+ * data is written completely.
+ */
+LUA_FUNCTION_DEF(tcp_sync, write);
+
+LUA_FUNCTION_DEF(tcp_sync, gc);
+
+static void lua_tcp_sync_session_dtor(gpointer ud);
+
+static const struct luaL_reg tcp_sync_libm[] = {
+	LUA_INTERFACE_DEF(tcp_sync, close),
+	LUA_INTERFACE_DEF(tcp_sync, read_once),
+	LUA_INTERFACE_DEF(tcp_sync, write),
+	LUA_INTERFACE_DEF(tcp_sync, eof),
+	LUA_INTERFACE_DEF(tcp_sync, shutdown),
+	{"__gc", lua_tcp_sync_gc},
+	{"__tostring", rspamd_lua_class_tostring},
+	{NULL, NULL}};
+
+struct lua_tcp_read_handler {
+	gchar *stop_pattern;
+	guint plen;
+	gint cbref;
+};
+
+struct lua_tcp_write_handler {
+	struct iovec *iov;
+	guint iovlen;
+	gint cbref;
+	gsize pos;
+	gsize total_bytes;
+};
+
+enum lua_tcp_handler_type {
+	LUA_WANT_WRITE = 0,
+	LUA_WANT_READ,
+	LUA_WANT_CONNECT
+};
+
+struct lua_tcp_handler {
+	union {
+		struct lua_tcp_read_handler r;
+		struct lua_tcp_write_handler w;
+	} h;
+	enum lua_tcp_handler_type type;
+};
+
+struct lua_tcp_dtor {
+	rspamd_mempool_destruct_t dtor;
+	void *data;
+	struct lua_tcp_dtor *next;
+};
+
+#define LUA_TCP_FLAG_PARTIAL (1u << 0u)
+#define LUA_TCP_FLAG_SHUTDOWN (1u << 2u)
+#define LUA_TCP_FLAG_CONNECTED (1u << 3u)
+#define LUA_TCP_FLAG_FINISHED (1u << 4u)
+#define LUA_TCP_FLAG_SYNC (1u << 5u)
+#define LUA_TCP_FLAG_RESOLVED (1u << 6u)
+#define LUA_TCP_FLAG_SSL (1u << 7u)
+#define LUA_TCP_FLAG_SSL_NOVERIFY (1u << 8u)
+
+#undef TCP_DEBUG_REFS
+#ifdef TCP_DEBUG_REFS
+#define TCP_RETAIN(x)                                                    \
+	do {                                                                 \
+		msg_info("retain ref %p, refcount: %d", (x), (x)->ref.refcount); \
+		REF_RETAIN(x);                                                   \
+	} while (0)
+
+#define TCP_RELEASE(x)                                                    \
+	do {                                                                  \
+		msg_info("release ref %p, refcount: %d", (x), (x)->ref.refcount); \
+		REF_RELEASE(x);                                                   \
+	} while (0)
+#else
+#define TCP_RETAIN(x) REF_RETAIN(x)
+#define TCP_RELEASE(x) REF_RELEASE(x)
+#endif
+
+struct lua_tcp_cbdata {
+	struct rspamd_async_session *session;
+	struct rspamd_async_event *async_ev;
+	struct ev_loop *event_loop;
+	rspamd_inet_addr_t *addr;
+	GByteArray *in;
+	GQueue *handlers;
+	gint fd;
+	gint connect_cb;
+	guint port;
+	guint flags;
+	gchar tag[7];
+	struct rspamd_io_ev ev;
+	struct lua_tcp_dtor *dtors;
+	ref_entry_t ref;
+	struct rspamd_task *task;
+	struct rspamd_symcache_dynamic_item *item;
+	struct thread_entry *thread;
+	struct rspamd_config *cfg;
+	struct rspamd_ssl_connection *ssl_conn;
+	gchar *hostname;
+	struct upstream *up;
+	gboolean eof;
+};
+
+#define IS_SYNC(c) (((c)->flags & LUA_TCP_FLAG_SYNC) != 0)
+
+#define msg_debug_tcp(...) rspamd_conditional_debug_fast(NULL, cbd->addr,                            \
+														 rspamd_lua_tcp_log_id, "lua_tcp", cbd->tag, \
+														 G_STRFUNC,                                  \
+														 __VA_ARGS__)
+
+INIT_LOG_MODULE(lua_tcp)
+
+static void lua_tcp_handler(int fd, short what, gpointer ud);
+static void lua_tcp_plan_handler_event(struct lua_tcp_cbdata *cbd,
+									   gboolean can_read, gboolean can_write);
+static void lua_tcp_unregister_event(struct lua_tcp_cbdata *cbd);
+
+static void
+lua_tcp_void_finalyser(gpointer arg)
+{
+}
+
+static const gdouble default_tcp_timeout = 5.0;
+
+static struct rspamd_dns_resolver *
+lua_tcp_global_resolver(struct ev_loop *ev_base,
+						struct rspamd_config *cfg)
+{
+	static struct rspamd_dns_resolver *global_resolver;
+
+	if (cfg && cfg->dns_resolver) {
+		return cfg->dns_resolver;
+	}
+
+	if (global_resolver == NULL) {
+		global_resolver = rspamd_dns_resolver_init(NULL, ev_base, cfg);
+	}
+
+	return global_resolver;
+}
+
+static gboolean
+lua_tcp_shift_handler(struct lua_tcp_cbdata *cbd)
+{
+	struct lua_tcp_handler *hdl;
+
+	hdl = g_queue_pop_head(cbd->handlers);
+
+	if (hdl == NULL) {
+		/* We are done */
+		return FALSE;
+	}
+
+	if (hdl->type == LUA_WANT_READ) {
+		msg_debug_tcp("switch from read handler %d", hdl->h.r.cbref);
+		if (hdl->h.r.cbref && hdl->h.r.cbref != -1) {
+			luaL_unref(cbd->cfg->lua_state, LUA_REGISTRYINDEX, hdl->h.r.cbref);
+		}
+
+		if (hdl->h.r.stop_pattern) {
+			g_free(hdl->h.r.stop_pattern);
+		}
+	}
+	else if (hdl->type == LUA_WANT_WRITE) {
+		msg_debug_tcp("switch from write handler %d", hdl->h.r.cbref);
+		if (hdl->h.w.cbref && hdl->h.w.cbref != -1) {
+			luaL_unref(cbd->cfg->lua_state, LUA_REGISTRYINDEX, hdl->h.w.cbref);
+		}
+
+		if (hdl->h.w.iov) {
+			g_free(hdl->h.w.iov);
+		}
+	}
+	else {
+		msg_debug_tcp("removing connect handler");
+		/* LUA_WANT_CONNECT: it doesn't allocate anything, nothing to do here */
+	}
+
+	g_free(hdl);
+
+	return TRUE;
+}
+
+static void
+lua_tcp_fin(gpointer arg)
+{
+	struct lua_tcp_cbdata *cbd = (struct lua_tcp_cbdata *) arg;
+	struct lua_tcp_dtor *dtor, *dttmp;
+
+	if (IS_SYNC(cbd) && cbd->task) {
+		/*
+		pointer is now becoming invalid, we should remove registered destructor,
+		all the necessary steps are done here
+		*/
+		rspamd_mempool_replace_destructor(cbd->task->task_pool,
+										  lua_tcp_sync_session_dtor, cbd, NULL);
+	}
+
+	msg_debug_tcp("finishing TCP %s connection", IS_SYNC(cbd) ? "sync" : "async");
+
+	if (cbd->connect_cb != -1) {
+		luaL_unref(cbd->cfg->lua_state, LUA_REGISTRYINDEX, cbd->connect_cb);
+	}
+
+	if (cbd->ssl_conn) {
+		/* TODO: postpone close in case ssl is used ! */
+		rspamd_ssl_connection_free(cbd->ssl_conn);
+	}
+
+	if (cbd->fd != -1) {
+		rspamd_ev_watcher_stop(cbd->event_loop, &cbd->ev);
+		close(cbd->fd);
+		cbd->fd = -1;
+	}
+
+	if (cbd->addr) {
+		rspamd_inet_address_free(cbd->addr);
+	}
+
+	if (cbd->up) {
+		rspamd_upstream_unref(cbd->up);
+	}
+
+	while (lua_tcp_shift_handler(cbd)) {}
+	g_queue_free(cbd->handlers);
+
+	LL_FOREACH_SAFE(cbd->dtors, dtor, dttmp)
+	{
+		dtor->dtor(dtor->data);
+		g_free(dtor);
+	}
+
+	g_byte_array_unref(cbd->in);
+	g_free(cbd->hostname);
+	g_free(cbd);
+}
+
+static struct lua_tcp_cbdata *
+lua_check_tcp(lua_State *L, gint pos)
+{
+	void *ud = rspamd_lua_check_udata(L, pos, "rspamd{tcp}");
+	luaL_argcheck(L, ud != NULL, pos, "'tcp' expected");
+	return ud ? *((struct lua_tcp_cbdata **) ud) : NULL;
+}
+
+static void
+lua_tcp_maybe_free(struct lua_tcp_cbdata *cbd)
+{
+	if (IS_SYNC(cbd)) {
+		/*
+		 * in this mode, we don't remove object, we only remove the event
+		 * Object is owned by lua and will be destroyed on __gc()
+		 */
+
+		if (cbd->item) {
+			rspamd_symcache_item_async_dec_check(cbd->task, cbd->item, M);
+			cbd->item = NULL;
+		}
+
+		if (cbd->async_ev) {
+			rspamd_session_remove_event(cbd->session, lua_tcp_void_finalyser, cbd);
+		}
+
+		cbd->async_ev = NULL;
+	}
+	else {
+		if (cbd->item) {
+			rspamd_symcache_item_async_dec_check(cbd->task, cbd->item, M);
+			cbd->item = NULL;
+		}
+
+		if (cbd->async_ev) {
+			rspamd_session_remove_event(cbd->session, lua_tcp_fin, cbd);
+		}
+		else {
+			lua_tcp_fin(cbd);
+		}
+	}
+}
+
+#ifdef __GNUC__
+static void
+lua_tcp_push_error(struct lua_tcp_cbdata *cbd, gboolean is_fatal,
+				   const char *err, ...) __attribute__((format(printf, 3, 4)));
+#endif
+
+static void lua_tcp_resume_thread_error_argp(struct lua_tcp_cbdata *cbd, const gchar *error, va_list argp);
+
+static void
+lua_tcp_push_error(struct lua_tcp_cbdata *cbd, gboolean is_fatal,
+				   const char *err, ...)
+{
+	va_list ap, ap_copy;
+	struct lua_tcp_cbdata **pcbd;
+	struct lua_tcp_handler *hdl;
+	gint cbref, top;
+	struct lua_callback_state cbs;
+	lua_State *L;
+	gboolean callback_called = FALSE;
+
+	if (is_fatal && cbd->up) {
+		rspamd_upstream_fail(cbd->up, false, err);
+	}
+
+	if (cbd->thread) {
+		va_start(ap, err);
+		lua_tcp_resume_thread_error_argp(cbd, err, ap);
+		va_end(ap);
+
+		return;
+	}
+
+	lua_thread_pool_prepare_callback(cbd->cfg->lua_thread_pool, &cbs);
+	L = cbs.L;
+
+	va_start(ap, err);
+
+	for (;;) {
+		hdl = g_queue_peek_head(cbd->handlers);
+
+		if (hdl == NULL) {
+			break;
+		}
+
+		if (hdl->type == LUA_WANT_READ) {
+			cbref = hdl->h.r.cbref;
+		}
+		else {
+			cbref = hdl->h.w.cbref;
+		}
+
+		if (cbref != -1) {
+			top = lua_gettop(L);
+			lua_rawgeti(L, LUA_REGISTRYINDEX, cbref);
+
+			/* Error message */
+			va_copy(ap_copy, ap);
+			lua_pushvfstring(L, err, ap_copy);
+			va_end(ap_copy);
+
+			/* Body */
+			lua_pushnil(L);
+			/* Connection */
+			pcbd = lua_newuserdata(L, sizeof(*pcbd));
+			*pcbd = cbd;
+			rspamd_lua_setclass(L, "rspamd{tcp}", -1);
+			TCP_RETAIN(cbd);
+
+			if (cbd->item) {
+				rspamd_symcache_set_cur_item(cbd->task, cbd->item);
+			}
+
+			if (lua_pcall(L, 3, 0, 0) != 0) {
+				msg_info("callback call failed: %s", lua_tostring(L, -1));
+			}
+
+			lua_settop(L, top);
+
+			TCP_RELEASE(cbd);
+
+			if ((cbd->flags & (LUA_TCP_FLAG_FINISHED | LUA_TCP_FLAG_CONNECTED)) ==
+				(LUA_TCP_FLAG_FINISHED | LUA_TCP_FLAG_CONNECTED)) {
+				/* A callback has called `close` method, so we need to release a refcount */
+				TCP_RELEASE(cbd);
+			}
+
+			callback_called = TRUE;
+		}
+
+		if (!is_fatal) {
+			if (callback_called) {
+				/* Stop on the first callback found */
+				break;
+			}
+			else {
+				/* Shift to another callback to inform about non fatal error */
+				msg_debug_tcp("non fatal error find matching callback");
+				lua_tcp_shift_handler(cbd);
+				continue;
+			}
+		}
+		else {
+			msg_debug_tcp("fatal error rollback all handlers");
+			lua_tcp_shift_handler(cbd);
+		}
+	}
+
+	va_end(ap);
+
+	lua_thread_pool_restore_callback(&cbs);
+}
+
+static void lua_tcp_resume_thread(struct lua_tcp_cbdata *cbd, const guint8 *str, gsize len);
+
+static void
+lua_tcp_push_data(struct lua_tcp_cbdata *cbd, const guint8 *str, gsize len)
+{
+	struct rspamd_lua_text *t;
+	struct lua_tcp_cbdata **pcbd;
+	struct lua_tcp_handler *hdl;
+	gint cbref, arg_cnt, top;
+	struct lua_callback_state cbs;
+	lua_State *L;
+
+	if (cbd->thread) {
+		lua_tcp_resume_thread(cbd, str, len);
+		return;
+	}
+
+	lua_thread_pool_prepare_callback(cbd->cfg->lua_thread_pool, &cbs);
+	L = cbs.L;
+
+	hdl = g_queue_peek_head(cbd->handlers);
+
+	g_assert(hdl != NULL);
+
+	if (hdl->type == LUA_WANT_READ) {
+		cbref = hdl->h.r.cbref;
+	}
+	else {
+		cbref = hdl->h.w.cbref;
+	}
+
+	if (cbref != -1) {
+		top = lua_gettop(L);
+		lua_rawgeti(L, LUA_REGISTRYINDEX, cbref);
+		/* Error */
+		lua_pushnil(L);
+		/* Body */
+
+		if (hdl->type == LUA_WANT_READ) {
+			t = lua_newuserdata(L, sizeof(*t));
+			rspamd_lua_setclass(L, "rspamd{text}", -1);
+			t->start = (const gchar *) str;
+			t->len = len;
+			t->flags = 0;
+			arg_cnt = 3;
+		}
+		else {
+			arg_cnt = 2;
+		}
+		/* Connection */
+		pcbd = lua_newuserdata(L, sizeof(*pcbd));
+		*pcbd = cbd;
+		rspamd_lua_setclass(L, "rspamd{tcp}", -1);
+
+		TCP_RETAIN(cbd);
+
+		if (cbd->item) {
+			rspamd_symcache_set_cur_item(cbd->task, cbd->item);
+		}
+
+		if (lua_pcall(L, arg_cnt, 0, 0) != 0) {
+			msg_info("callback call failed: %s", lua_tostring(L, -1));
+		}
+
+		lua_settop(L, top);
+		TCP_RELEASE(cbd);
+
+		if ((cbd->flags & (LUA_TCP_FLAG_FINISHED | LUA_TCP_FLAG_CONNECTED)) ==
+			(LUA_TCP_FLAG_FINISHED | LUA_TCP_FLAG_CONNECTED)) {
+			/* A callback has called `close` method, so we need to release a refcount */
+			TCP_RELEASE(cbd);
+		}
+	}
+
+	lua_thread_pool_restore_callback(&cbs);
+}
+
+static void
+lua_tcp_resume_thread_error_argp(struct lua_tcp_cbdata *cbd, const gchar *error, va_list argp)
+{
+	struct thread_entry *thread = cbd->thread;
+	lua_State *L = thread->lua_state;
+
+	lua_pushboolean(L, FALSE);
+	lua_pushvfstring(L, error, argp);
+
+	lua_tcp_shift_handler(cbd);
+	// lua_tcp_unregister_event (cbd);
+	lua_thread_pool_set_running_entry(cbd->cfg->lua_thread_pool, cbd->thread);
+	lua_thread_resume(thread, 2);
+	TCP_RELEASE(cbd);
+}
+
+static void
+lua_tcp_resume_thread(struct lua_tcp_cbdata *cbd, const guint8 *str, gsize len)
+{
+	/*
+	 * typical call returns:
+	 *
+	 * read:
+	 *  error:
+	 *    (nil, error message)
+	 *  got data:
+	 *    (true, data)
+	 * write/connect:
+	 *   error:
+	 *     (nil, error message)
+	 *   wrote
+	 *     (true)
+	 */
+
+	lua_State *L = cbd->thread->lua_state;
+	struct lua_tcp_handler *hdl;
+
+	hdl = g_queue_peek_head(cbd->handlers);
+
+	lua_pushboolean(L, TRUE);
+	if (hdl->type == LUA_WANT_READ) {
+		lua_pushlstring(L, str, len);
+	}
+	else {
+		lua_pushnil(L);
+	}
+
+	lua_tcp_shift_handler(cbd);
+	lua_thread_pool_set_running_entry(cbd->cfg->lua_thread_pool,
+									  cbd->thread);
+
+	if (cbd->item) {
+		rspamd_symcache_set_cur_item(cbd->task, cbd->item);
+	}
+
+	lua_thread_resume(cbd->thread, 2);
+
+	TCP_RELEASE(cbd);
+}
+
+static void
+lua_tcp_plan_read(struct lua_tcp_cbdata *cbd)
+{
+	rspamd_ev_watcher_reschedule(cbd->event_loop, &cbd->ev, EV_READ);
+}
+
+static void
+lua_tcp_connect_helper(struct lua_tcp_cbdata *cbd)
+{
+	/* This is used for sync mode only */
+	lua_State *L = cbd->thread->lua_state;
+
+	struct lua_tcp_cbdata **pcbd;
+
+	lua_pushboolean(L, TRUE);
+
+	lua_thread_pool_set_running_entry(cbd->cfg->lua_thread_pool, cbd->thread);
+	pcbd = lua_newuserdata(L, sizeof(*pcbd));
+	*pcbd = cbd;
+	rspamd_lua_setclass(L, "rspamd{tcp_sync}", -1);
+	msg_debug_tcp("tcp connected");
+
+	lua_tcp_shift_handler(cbd);
+
+	// lua_tcp_unregister_event (cbd);
+	lua_thread_resume(cbd->thread, 2);
+	TCP_RELEASE(cbd);
+}
+
+static void
+lua_tcp_write_helper(struct lua_tcp_cbdata *cbd)
+{
+	struct iovec *start;
+	guint niov, i;
+	gint flags = 0;
+	bool allocated_iov = false;
+	gsize remain;
+	gssize r;
+	struct iovec *cur_iov;
+	struct lua_tcp_handler *hdl;
+	struct lua_tcp_write_handler *wh;
+	struct msghdr msg;
+
+	hdl = g_queue_peek_head(cbd->handlers);
+
+	g_assert(hdl != NULL && hdl->type == LUA_WANT_WRITE);
+	wh = &hdl->h.w;
+
+	if (wh->pos == wh->total_bytes) {
+		goto call_finish_handler;
+	}
+
+	start = &wh->iov[0];
+	niov = wh->iovlen;
+	remain = wh->pos;
+	/* We know that niov is small enough for that */
+
+	if (niov < 1024) {
+		cur_iov = g_alloca(niov * sizeof(struct iovec));
+	}
+	else {
+		cur_iov = g_malloc0(niov * sizeof(struct iovec));
+		allocated_iov = true;
+	}
+
+	memcpy(cur_iov, wh->iov, niov * sizeof(struct iovec));
+
+	for (i = 0; i < wh->iovlen && remain > 0; i++) {
+		/* Find out the first iov required */
+		start = &cur_iov[i];
+		if (start->iov_len <= remain) {
+			remain -= start->iov_len;
+			start = &cur_iov[i + 1];
+			niov--;
+		}
+		else {
+			start->iov_base = (void *) ((char *) start->iov_base + remain);
+			start->iov_len -= remain;
+			remain = 0;
+		}
+	}
+
+	memset(&msg, 0, sizeof(msg));
+	msg.msg_iov = start;
+	msg.msg_iovlen = MIN(IOV_MAX, niov);
+	g_assert(niov > 0);
+#ifdef MSG_NOSIGNAL
+	flags = MSG_NOSIGNAL;
+#endif
+
+	msg_debug_tcp("want write %d io vectors of %d", (int) msg.msg_iovlen,
+				  (int) niov);
+
+	if (cbd->ssl_conn) {
+		r = rspamd_ssl_writev(cbd->ssl_conn, msg.msg_iov, msg.msg_iovlen);
+	}
+	else {
+		r = sendmsg(cbd->fd, &msg, flags);
+	}
+
+	if (allocated_iov) {
+		g_free(cur_iov);
+	}
+
+	if (r == -1) {
+		if (!(cbd->ssl_conn)) {
+			if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR) {
+				msg_debug_tcp("got temporary failure, retry write");
+				lua_tcp_plan_handler_event(cbd, TRUE, TRUE);
+				return;
+			}
+			else {
+				lua_tcp_push_error(cbd, TRUE,
+								   "IO write error while trying to write %d bytes: %s",
+								   (gint) remain, strerror(errno));
+
+				msg_debug_tcp("write error, terminate connection");
+				TCP_RELEASE(cbd);
+			}
+		}
+
+		return;
+	}
+	else {
+		wh->pos += r;
+	}
+
+	msg_debug_tcp("written %z bytes: %z/%z", r,
+				  wh->pos, wh->total_bytes);
+
+	if (wh->pos >= wh->total_bytes) {
+		goto call_finish_handler;
+	}
+	else {
+		/* Want to write more */
+		if (r > 0) {
+			/* XXX: special case: we know that we want to write more data
+			 * than it is available in iov function.
+			 *
+			 * Hence, we need to check if we can write more at some point...
+			 */
+			lua_tcp_write_helper(cbd);
+		}
+	}
+
+	return;
+
+call_finish_handler:
+
+	msg_debug_tcp("finishing TCP write, calling TCP handler");
+
+	if ((cbd->flags & LUA_TCP_FLAG_SHUTDOWN)) {
+		/* Half close the connection */
+		shutdown(cbd->fd, SHUT_WR);
+		cbd->flags &= ~LUA_TCP_FLAG_SHUTDOWN;
+	}
+
+	if (cbd->up) {
+		rspamd_upstream_ok(cbd->up);
+	}
+
+	lua_tcp_push_data(cbd, NULL, 0);
+	if (!IS_SYNC(cbd)) {
+		lua_tcp_shift_handler(cbd);
+		lua_tcp_plan_handler_event(cbd, TRUE, TRUE);
+	}
+}
+
+static gboolean
+lua_tcp_process_read_handler(struct lua_tcp_cbdata *cbd,
+							 struct lua_tcp_read_handler *rh, gboolean eof)
+{
+	guint slen;
+	goffset pos;
+
+	if (rh->stop_pattern) {
+		slen = rh->plen;
+
+		if (cbd->in->len >= slen) {
+			if ((pos = rspamd_substring_search(cbd->in->data, cbd->in->len,
+											   rh->stop_pattern, slen)) != -1) {
+				msg_debug_tcp("found TCP stop pattern");
+				lua_tcp_push_data(cbd, cbd->in->data, pos);
+
+				if (!IS_SYNC(cbd)) {
+					lua_tcp_shift_handler(cbd);
+				}
+				if (pos + slen < cbd->in->len) {
+					/* We have a leftover */
+					memmove(cbd->in->data, cbd->in->data + pos + slen,
+							cbd->in->len - (pos + slen));
+					cbd->in->len = cbd->in->len - (pos + slen);
+				}
+				else {
+					cbd->in->len = 0;
+				}
+
+				return TRUE;
+			}
+			else {
+				/* Plan new read */
+				msg_debug_tcp("NOT found TCP stop pattern");
+
+				if (!cbd->eof) {
+					lua_tcp_plan_read(cbd);
+				}
+				else {
+					/* Got session finished but no stop pattern */
+					lua_tcp_push_error(cbd, TRUE,
+									   "IO read error: connection terminated");
+				}
+			}
+		}
+	}
+	else {
+		msg_debug_tcp("read TCP partial data %d bytes", cbd->in->len);
+		slen = cbd->in->len;
+
+		/* we have eaten all the data, handler should not know that there is something */
+		cbd->in->len = 0;
+		lua_tcp_push_data(cbd, cbd->in->data, slen);
+		if (!IS_SYNC(cbd)) {
+			lua_tcp_shift_handler(cbd);
+		}
+
+		return TRUE;
+	}
+
+	return FALSE;
+}
+
+static void
+lua_tcp_process_read(struct lua_tcp_cbdata *cbd,
+					 guchar *in, gssize r)
+{
+	struct lua_tcp_handler *hdl;
+	struct lua_tcp_read_handler *rh;
+
+	hdl = g_queue_peek_head(cbd->handlers);
+
+	g_assert(hdl != NULL && hdl->type == LUA_WANT_READ);
+	rh = &hdl->h.r;
+
+	if (r > 0) {
+		if (cbd->flags & LUA_TCP_FLAG_PARTIAL) {
+			lua_tcp_push_data(cbd, in, r);
+			/* Plan next event */
+			lua_tcp_plan_read(cbd);
+		}
+		else {
+			g_byte_array_append(cbd->in, in, r);
+
+			if (!lua_tcp_process_read_handler(cbd, rh, FALSE)) {
+				/* Plan more read */
+				lua_tcp_plan_read(cbd);
+			}
+			else {
+				/* Go towards the next handler */
+				if (!IS_SYNC(cbd)) {
+					lua_tcp_plan_handler_event(cbd, TRUE, TRUE);
+				}
+			}
+		}
+	}
+	else if (r == 0) {
+		/* EOF */
+		cbd->eof = TRUE;
+		if (cbd->in->len > 0) {
+			/* We have some data to process */
+			lua_tcp_process_read_handler(cbd, rh, TRUE);
+		}
+		else {
+			lua_tcp_push_error(cbd, TRUE, "IO read error: connection terminated");
+
+			if ((cbd->flags & LUA_TCP_FLAG_FINISHED)) {
+				/* A callback has called `close` method, so we need to release a refcount */
+				TCP_RELEASE(cbd);
+			}
+		}
+
+		lua_tcp_plan_handler_event(cbd, FALSE, FALSE);
+	}
+	else {
+		/* An error occurred */
+		if (errno == EAGAIN || errno == EINTR) {
+			/* Restart call */
+			lua_tcp_plan_read(cbd);
+
+			return;
+		}
+
+		/* Fatal error */
+		cbd->eof = TRUE;
+		if (cbd->in->len > 0) {
+			/* We have some data to process */
+			lua_tcp_process_read_handler(cbd, rh, TRUE);
+		}
+		else {
+			lua_tcp_push_error(cbd, TRUE,
+							   "IO read error while trying to read data: %s",
+							   strerror(errno));
+
+			if ((cbd->flags & LUA_TCP_FLAG_FINISHED)) {
+				/* A callback has called `close` method, so we need to release a refcount */
+				TCP_RELEASE(cbd);
+			}
+		}
+
+		lua_tcp_plan_handler_event(cbd, FALSE, FALSE);
+	}
+}
+
+static void
+lua_tcp_handler(int fd, short what, gpointer ud)
+{
+	struct lua_tcp_cbdata *cbd = ud;
+	guchar inbuf[8192];
+	gssize r;
+	gint so_error = 0;
+	socklen_t so_len = sizeof(so_error);
+	struct lua_callback_state cbs;
+	lua_State *L;
+	enum lua_tcp_handler_type event_type;
+	TCP_RETAIN(cbd);
+
+	msg_debug_tcp("processed TCP event: %d", what);
+
+	struct lua_tcp_handler *rh = g_queue_peek_head(cbd->handlers);
+	event_type = rh->type;
+
+	rspamd_ev_watcher_stop(cbd->event_loop, &cbd->ev);
+
+	if (what == EV_READ) {
+		if (cbd->ssl_conn) {
+			r = rspamd_ssl_read(cbd->ssl_conn, inbuf, sizeof(inbuf));
+		}
+		else {
+			r = read(cbd->fd, inbuf, sizeof(inbuf));
+		}
+
+		lua_tcp_process_read(cbd, inbuf, r);
+	}
+	else if (what == EV_WRITE) {
+
+		if (!(cbd->flags & LUA_TCP_FLAG_CONNECTED)) {
+			if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &so_error, &so_len) == -1) {
+				lua_tcp_push_error(cbd, TRUE, "Cannot get socket error: %s",
+								   strerror(errno));
+				TCP_RELEASE(cbd);
+				goto out;
+			}
+			else if (so_error != 0) {
+				lua_tcp_push_error(cbd, TRUE, "Socket error detected: %s",
+								   strerror(so_error));
+				TCP_RELEASE(cbd);
+				goto out;
+			}
+			else {
+				cbd->flags |= LUA_TCP_FLAG_CONNECTED;
+
+				if (cbd->connect_cb != -1) {
+					struct lua_tcp_cbdata **pcbd;
+					gint top;
+
+					lua_thread_pool_prepare_callback(cbd->cfg->lua_thread_pool, &cbs);
+					L = cbs.L;
+
+					top = lua_gettop(L);
+					lua_rawgeti(L, LUA_REGISTRYINDEX, cbd->connect_cb);
+					pcbd = lua_newuserdata(L, sizeof(*pcbd));
+					*pcbd = cbd;
+					TCP_RETAIN(cbd);
+					rspamd_lua_setclass(L, "rspamd{tcp}", -1);
+
+					if (cbd->item) {
+						rspamd_symcache_set_cur_item(cbd->task, cbd->item);
+					}
+
+					if (lua_pcall(L, 1, 0, 0) != 0) {
+						msg_info("callback call failed: %s", lua_tostring(L, -1));
+					}
+
+					lua_settop(L, top);
+					TCP_RELEASE(cbd);
+					lua_thread_pool_restore_callback(&cbs);
+
+					if ((cbd->flags & (LUA_TCP_FLAG_FINISHED | LUA_TCP_FLAG_CONNECTED)) ==
+						(LUA_TCP_FLAG_FINISHED | LUA_TCP_FLAG_CONNECTED)) {
+						/* A callback has called `close` method, so we need to release a refcount */
+						TCP_RELEASE(cbd);
+					}
+				}
+			}
+		}
+
+		if (event_type == LUA_WANT_WRITE) {
+			lua_tcp_write_helper(cbd);
+		}
+		else if (event_type == LUA_WANT_CONNECT) {
+			lua_tcp_connect_helper(cbd);
+		}
+		else {
+			g_assert_not_reached();
+		}
+
+		if ((cbd->flags & (LUA_TCP_FLAG_FINISHED | LUA_TCP_FLAG_CONNECTED)) ==
+			(LUA_TCP_FLAG_FINISHED | LUA_TCP_FLAG_CONNECTED)) {
+			/* A callback has called `close` method, so we need to release a refcount */
+			TCP_RELEASE(cbd);
+		}
+	}
+	else {
+		lua_tcp_push_error(cbd, TRUE, "IO timeout");
+		TCP_RELEASE(cbd);
+	}
+
+out:
+	TCP_RELEASE(cbd);
+}
+
+static void
+lua_tcp_plan_handler_event(struct lua_tcp_cbdata *cbd, gboolean can_read,
+						   gboolean can_write)
+{
+	struct lua_tcp_handler *hdl;
+
+	hdl = g_queue_peek_head(cbd->handlers);
+
+	if (hdl == NULL) {
+		if (!(cbd->flags & LUA_TCP_FLAG_FINISHED)) {
+			/* We are finished with a connection */
+			msg_debug_tcp("no handlers left, finish session");
+			cbd->flags |= LUA_TCP_FLAG_FINISHED;
+			TCP_RELEASE(cbd);
+		}
+	}
+	else {
+		if (hdl->type == LUA_WANT_READ) {
+
+			/* We need to check if we have some leftover in the buffer */
+			if (cbd->in->len > 0) {
+				msg_debug_tcp("process read buffer leftover");
+				if (lua_tcp_process_read_handler(cbd, &hdl->h.r, FALSE)) {
+					if (!IS_SYNC(cbd)) {
+						/* We can go to the next handler */
+						lua_tcp_plan_handler_event(cbd, can_read, can_write);
+					}
+				}
+			}
+			else {
+				if (can_read) {
+					/* We need to plan a new event */
+					msg_debug_tcp("plan new read");
+					rspamd_ev_watcher_reschedule(cbd->event_loop, &cbd->ev,
+												 EV_READ);
+				}
+				else {
+					/* Cannot read more */
+					msg_debug_tcp("cannot read more");
+					lua_tcp_push_error(cbd, FALSE, "EOF, cannot read more data");
+					if (!IS_SYNC(cbd)) {
+						lua_tcp_shift_handler(cbd);
+						lua_tcp_plan_handler_event(cbd, can_read, can_write);
+					}
+				}
+			}
+		}
+		else if (hdl->type == LUA_WANT_WRITE) {
+			/*
+			 * We need to plan write event if there is something in the
+			 * write request
+			 */
+
+			if (hdl->h.w.pos < hdl->h.w.total_bytes) {
+				msg_debug_tcp("plan new write");
+				if (can_write) {
+					rspamd_ev_watcher_reschedule(cbd->event_loop, &cbd->ev,
+												 EV_WRITE);
+				}
+				else {
+					/* Cannot write more */
+					lua_tcp_push_error(cbd, FALSE, "EOF, cannot write more data");
+					if (!IS_SYNC(cbd)) {
+						lua_tcp_shift_handler(cbd);
+						lua_tcp_plan_handler_event(cbd, can_read, can_write);
+					}
+				}
+			}
+			else {
+				/* We shouldn't have empty write handlers */
+				g_assert_not_reached();
+			}
+		}
+		else { /* LUA_WANT_CONNECT */
+			msg_debug_tcp("plan new connect");
+			rspamd_ev_watcher_reschedule(cbd->event_loop, &cbd->ev,
+										 EV_WRITE);
+		}
+	}
+}
+
+static gboolean
+lua_tcp_register_event(struct lua_tcp_cbdata *cbd)
+{
+	if (cbd->session) {
+		event_finalizer_t fin = IS_SYNC(cbd) ? lua_tcp_void_finalyser : lua_tcp_fin;
+
+		if (cbd->item) {
+			cbd->async_ev = rspamd_session_add_event_full(cbd->session, fin, cbd, M,
+														  rspamd_symcache_dyn_item_name(cbd->task, cbd->item));
+		}
+		else {
+			cbd->async_ev = rspamd_session_add_event(cbd->session, fin, cbd, M);
+		}
+
+		if (!cbd->async_ev) {
+			return FALSE;
+		}
+	}
+
+	return TRUE;
+}
+
+static void
+lua_tcp_register_watcher(struct lua_tcp_cbdata *cbd)
+{
+	if (cbd->item && cbd->task) {
+		rspamd_symcache_item_async_inc(cbd->task, cbd->item, M);
+	}
+}
+
+static void
+lua_tcp_ssl_on_error(gpointer ud, GError *err)
+{
+	struct lua_tcp_cbdata *cbd = (struct lua_tcp_cbdata *) ud;
+
+	if (err) {
+		lua_tcp_push_error(cbd, TRUE, "ssl error: %s", err->message);
+	}
+	else {
+		lua_tcp_push_error(cbd, TRUE, "ssl error: unknown error");
+	}
+
+	TCP_RELEASE(cbd);
+}
+
+static gboolean
+lua_tcp_make_connection(struct lua_tcp_cbdata *cbd)
+{
+	int fd;
+
+	rspamd_inet_address_set_port(cbd->addr, cbd->port);
+	fd = rspamd_inet_address_connect(cbd->addr, SOCK_STREAM, TRUE);
+
+	if (fd == -1) {
+		if (cbd->session) {
+			rspamd_mempool_t *pool = rspamd_session_mempool(cbd->session);
+			msg_info_pool("cannot connect to %s (%s): %s",
+						  rspamd_inet_address_to_string(cbd->addr),
+						  cbd->hostname,
+						  strerror(errno));
+		}
+		else {
+			msg_info("cannot connect to %s (%s): %s",
+					 rspamd_inet_address_to_string(cbd->addr),
+					 cbd->hostname,
+					 strerror(errno));
+		}
+
+		return FALSE;
+	}
+
+	cbd->fd = fd;
+
+#if 0
+	if (!(cbd->flags & LUA_TCP_FLAG_RESOLVED)) {
+		/* We come here without resolving, so we need to add a watcher */
+		lua_tcp_register_watcher (cbd);
+	}
+	else {
+		cbd->flags |= LUA_TCP_FLAG_RESOLVED;
+	}
+#endif
+
+	if (cbd->flags & LUA_TCP_FLAG_SSL) {
+		gpointer ssl_ctx;
+		gboolean verify_peer;
+
+		if (cbd->flags & LUA_TCP_FLAG_SSL_NOVERIFY) {
+			ssl_ctx = cbd->cfg->libs_ctx->ssl_ctx_noverify;
+			verify_peer = FALSE;
+		}
+		else {
+			ssl_ctx = cbd->cfg->libs_ctx->ssl_ctx;
+			verify_peer = TRUE;
+		}
+
+		cbd->ssl_conn = rspamd_ssl_connection_new(ssl_ctx,
+												  cbd->event_loop,
+												  verify_peer,
+												  cbd->tag);
+
+		if (!rspamd_ssl_connect_fd(cbd->ssl_conn, fd, cbd->hostname, &cbd->ev,
+								   cbd->ev.timeout, lua_tcp_handler, lua_tcp_ssl_on_error, cbd)) {
+			lua_tcp_push_error(cbd, TRUE, "ssl connection failed: %s",
+							   strerror(errno));
+
+			return FALSE;
+		}
+		else {
+			lua_tcp_register_event(cbd);
+		}
+	}
+	else {
+		rspamd_ev_watcher_init(&cbd->ev, cbd->fd, EV_WRITE,
+							   lua_tcp_handler, cbd);
+		lua_tcp_register_event(cbd);
+		lua_tcp_plan_handler_event(cbd, TRUE, TRUE);
+	}
+
+
+	return TRUE;
+}
+
+static void
+lua_tcp_dns_handler(struct rdns_reply *reply, gpointer ud)
+{
+	struct lua_tcp_cbdata *cbd = (struct lua_tcp_cbdata *) ud;
+	const struct rdns_request_name *rn;
+
+	if (reply->code != RDNS_RC_NOERROR) {
+		rn = rdns_request_get_name(reply->request, NULL);
+		lua_tcp_push_error(cbd, TRUE, "unable to resolve host: %s",
+						   rn->name);
+		TCP_RELEASE(cbd);
+	}
+	else {
+		/*
+		 * We set this flag as it means that we have already registered the watcher
+		 * when started DNS query
+		 */
+		struct rdns_reply_entry *entry;
+
+		DL_FOREACH(reply->entries, entry)
+		{
+			if (entry->type == RDNS_REQUEST_A) {
+				cbd->addr = rspamd_inet_address_new(AF_INET,
+													&entry->content.a.addr);
+				break;
+			}
+			else if (entry->type == RDNS_REQUEST_AAAA) {
+				cbd->addr = rspamd_inet_address_new(AF_INET6,
+													&entry->content.aaa.addr);
+				break;
+			}
+		}
+
+		if (cbd->addr == NULL) {
+			rn = rdns_request_get_name(reply->request, NULL);
+			lua_tcp_push_error(cbd, TRUE, "unable to resolve host: %s; no records with this name",
+							   rn->name);
+			TCP_RELEASE(cbd);
+			return;
+		}
+
+		cbd->flags |= LUA_TCP_FLAG_RESOLVED;
+		rspamd_inet_address_set_port(cbd->addr, cbd->port);
+
+		if (!lua_tcp_make_connection(cbd)) {
+			lua_tcp_push_error(cbd, TRUE, "unable to make connection to the host %s",
+							   rspamd_inet_address_to_string(cbd->addr));
+			TCP_RELEASE(cbd);
+		}
+	}
+}
+
+static gboolean
+lua_tcp_arg_toiovec(lua_State *L, gint pos, struct lua_tcp_cbdata *cbd,
+					struct iovec *vec)
+{
+	struct rspamd_lua_text *t;
+	gsize len;
+	const gchar *str;
+	struct lua_tcp_dtor *dtor;
+
+	if (lua_type(L, pos) == LUA_TUSERDATA) {
+		t = lua_check_text(L, pos);
+
+		if (t) {
+			vec->iov_base = (void *) t->start;
+			vec->iov_len = t->len;
+
+			if (t->flags & RSPAMD_TEXT_FLAG_OWN) {
+				/* Steal ownership */
+				t->flags = 0;
+				dtor = g_malloc0(sizeof(*dtor));
+				dtor->dtor = g_free;
+				dtor->data = (void *) t->start;
+				LL_PREPEND(cbd->dtors, dtor);
+			}
+		}
+		else {
+			msg_err("bad userdata argument at position %d", pos);
+			return FALSE;
+		}
+	}
+	else if (lua_type(L, pos) == LUA_TSTRING) {
+		str = luaL_checklstring(L, pos, &len);
+		vec->iov_base = g_malloc(len);
+		dtor = g_malloc0(sizeof(*dtor));
+		dtor->dtor = g_free;
+		dtor->data = vec->iov_base;
+		LL_PREPEND(cbd->dtors, dtor);
+		memcpy(vec->iov_base, str, len);
+		vec->iov_len = len;
+	}
+	else {
+		msg_err("bad argument at position %d", pos);
+		return FALSE;
+	}
+
+	return TRUE;
+}
+
+/***
+ * @function rspamd_tcp.request({params})
+ * This function creates and sends TCP request to the specified host and port,
+ * resolves hostname (if needed) and invokes continuation callback upon data received
+ * from the remote peer. This function accepts table of arguments with the following
+ * attributes
+ *
+ * - `task`: rspamd task objects (implies `pool`, `session`, `ev_base` and `resolver` arguments)
+ * - `ev_base`: event base (if no task specified)
+ * - `resolver`: DNS resolver (no task)
+ * - `session`: events session (no task)
+ * - `host`: IP or name of the peer (required)
+ * - `port`: remote port to use
+ * - `data`: a table of strings or `rspamd_text` objects that contains data pieces
+ * - `callback`: continuation function (required)
+ * - `on_connect`: callback called on connection success
+ * - `timeout`: floating point value that specifies timeout for IO operations in **seconds**
+ * - `partial`: boolean flag that specifies that callback should be called on any data portion received
+ * - `stop_pattern`: stop reading on finding a certain pattern (e.g. \r\n.\r\n for smtp)
+ * - `shutdown`: half-close socket after writing (boolean: default false)
+ * - `read`: read response after sending request (boolean: default true)
+ * - `upstream`: optional upstream object that would be used to get an address
+ * @return {boolean} true if request has been sent
+ */
+static gint
+lua_tcp_request(lua_State *L)
+{
+	LUA_TRACE_POINT;
+	const gchar *host;
+	gchar *stop_pattern = NULL;
+	guint port;
+	gint cbref, tp, conn_cbref = -1;
+	gsize plen = 0;
+	struct ev_loop *event_loop = NULL;
+	struct lua_tcp_cbdata *cbd;
+	struct rspamd_dns_resolver *resolver = NULL;
+	struct rspamd_async_session *session = NULL;
+	struct rspamd_task *task = NULL;
+	struct rspamd_config *cfg = NULL;
+	struct iovec *iov = NULL;
+	struct upstream *up = NULL;
+	guint niov = 0, total_out;
+	guint64 h;
+	gdouble timeout = default_tcp_timeout;
+	gboolean partial = FALSE, do_shutdown = FALSE, do_read = TRUE,
+			 ssl = FALSE, ssl_noverify = FALSE;
+
+	if (lua_type(L, 1) == LUA_TTABLE) {
+		lua_pushstring(L, "host");
+		lua_gettable(L, -2);
+		host = luaL_checkstring(L, -1);
+		lua_pop(L, 1);
+
+		lua_pushstring(L, "port");
+		lua_gettable(L, -2);
+		if (lua_type(L, -1) == LUA_TNUMBER) {
+			port = lua_tointeger(L, -1);
+		}
+		else {
+			/* We assume that it is a unix socket */
+			port = 0;
+		}
+
+		lua_pop(L, 1);
+
+		lua_pushstring(L, "callback");
+		lua_gettable(L, -2);
+		if (host == NULL || lua_type(L, -1) != LUA_TFUNCTION) {
+			lua_pop(L, 1);
+			msg_err("tcp request has bad params");
+			lua_pushboolean(L, FALSE);
+			return 1;
+		}
+		cbref = luaL_ref(L, LUA_REGISTRYINDEX);
+
+		cbd = g_malloc0(sizeof(*cbd));
+
+		lua_pushstring(L, "task");
+		lua_gettable(L, -2);
+		if (lua_type(L, -1) == LUA_TUSERDATA) {
+			task = lua_check_task(L, -1);
+			event_loop = task->event_loop;
+			resolver = task->resolver;
+			session = task->s;
+			cfg = task->cfg;
+		}
+		lua_pop(L, 1);
+
+		if (task == NULL) {
+			lua_pushstring(L, "ev_base");
+			lua_gettable(L, -2);
+			if (rspamd_lua_check_udata_maybe(L, -1, "rspamd{ev_base}")) {
+				event_loop = *(struct ev_loop **) lua_touserdata(L, -1);
+			}
+			else {
+				g_free(cbd);
+
+				return luaL_error(L, "event loop is required");
+			}
+			lua_pop(L, 1);
+
+			lua_pushstring(L, "session");
+			lua_gettable(L, -2);
+			if (rspamd_lua_check_udata_maybe(L, -1, "rspamd{session}")) {
+				session = *(struct rspamd_async_session **) lua_touserdata(L, -1);
+			}
+			else {
+				session = NULL;
+			}
+			lua_pop(L, 1);
+
+			lua_pushstring(L, "config");
+			lua_gettable(L, -2);
+			if (rspamd_lua_check_udata_maybe(L, -1, "rspamd{config}")) {
+				cfg = *(struct rspamd_config **) lua_touserdata(L, -1);
+			}
+			else {
+				cfg = NULL;
+			}
+			lua_pop(L, 1);
+
+			lua_pushstring(L, "resolver");
+			lua_gettable(L, -2);
+			if (rspamd_lua_check_udata_maybe(L, -1, "rspamd{resolver}")) {
+				resolver = *(struct rspamd_dns_resolver **) lua_touserdata(L, -1);
+			}
+			else {
+				resolver = lua_tcp_global_resolver(event_loop, cfg);
+			}
+			lua_pop(L, 1);
+		}
+
+		lua_pushstring(L, "timeout");
+		lua_gettable(L, -2);
+		if (lua_type(L, -1) == LUA_TNUMBER) {
+			timeout = lua_tonumber(L, -1);
+		}
+		lua_pop(L, 1);
+
+		lua_pushstring(L, "stop_pattern");
+		lua_gettable(L, -2);
+		if (lua_type(L, -1) == LUA_TSTRING) {
+			const gchar *p;
+
+			p = lua_tolstring(L, -1, &plen);
+
+			if (p && plen > 0) {
+				stop_pattern = g_malloc(plen);
+				memcpy(stop_pattern, p, plen);
+			}
+		}
+		lua_pop(L, 1);
+
+		lua_pushstring(L, "partial");
+		lua_gettable(L, -2);
+		if (lua_type(L, -1) == LUA_TBOOLEAN) {
+			partial = lua_toboolean(L, -1);
+		}
+		lua_pop(L, 1);
+
+		lua_pushstring(L, "shutdown");
+		lua_gettable(L, -2);
+		if (lua_type(L, -1) == LUA_TBOOLEAN) {
+			do_shutdown = lua_toboolean(L, -1);
+		}
+		lua_pop(L, 1);
+
+		lua_pushstring(L, "read");
+		lua_gettable(L, -2);
+		if (lua_type(L, -1) == LUA_TBOOLEAN) {
+			do_read = lua_toboolean(L, -1);
+		}
+		lua_pop(L, 1);
+
+		lua_pushstring(L, "ssl");
+		lua_gettable(L, -2);
+		if (lua_type(L, -1) == LUA_TBOOLEAN) {
+			ssl = lua_toboolean(L, -1);
+		}
+		lua_pop(L, 1);
+
+		lua_pushstring(L, "ssl_noverify");
+		lua_gettable(L, -2);
+		if (lua_type(L, -1) == LUA_TBOOLEAN) {
+			ssl_noverify = lua_toboolean(L, -1);
+			lua_pop(L, 1);
+		}
+		else {
+			lua_pop(L, 1); /* Previous nil... */
+			/* Similar to lua http, meh... */
+			lua_pushstring(L, "no_ssl_verify");
+			lua_gettable(L, -2);
+
+			if (lua_type(L, -1) == LUA_TBOOLEAN) {
+				ssl_noverify = lua_toboolean(L, -1);
+			}
+
+			lua_pop(L, 1);
+		}
+
+		lua_pushstring(L, "on_connect");
+		lua_gettable(L, -2);
+
+		if (lua_type(L, -1) == LUA_TFUNCTION) {
+			conn_cbref = luaL_ref(L, LUA_REGISTRYINDEX);
+		}
+		else {
+			lua_pop(L, 1);
+		}
+
+		lua_pushstring(L, "upstream");
+		lua_gettable(L, 1);
+
+		if (lua_type(L, -1) == LUA_TUSERDATA) {
+			struct rspamd_lua_upstream *lup = lua_check_upstream(L, -1);
+
+			if (lup) {
+				/* Preserve pointer in case if lup is destructed */
+				up = lup->up;
+			}
+		}
+
+		lua_pop(L, 1);
+
+		lua_pushstring(L, "data");
+		lua_gettable(L, -2);
+		total_out = 0;
+
+		tp = lua_type(L, -1);
+		if (tp == LUA_TSTRING || tp == LUA_TUSERDATA) {
+			iov = g_malloc(sizeof(*iov));
+			niov = 1;
+
+			if (!lua_tcp_arg_toiovec(L, -1, cbd, iov)) {
+				lua_pop(L, 1);
+				msg_err("tcp request has bad data argument");
+				lua_pushboolean(L, FALSE);
+				g_free(iov);
+				g_free(cbd);
+
+				return 1;
+			}
+
+			total_out = iov[0].iov_len;
+		}
+		else if (tp == LUA_TTABLE) {
+			/* Count parts */
+			lua_pushnil(L);
+			while (lua_next(L, -2) != 0) {
+				niov++;
+				lua_pop(L, 1);
+			}
+
+			iov = g_malloc(sizeof(*iov) * niov);
+			lua_pushnil(L);
+			niov = 0;
+
+			while (lua_next(L, -2) != 0) {
+				if (!lua_tcp_arg_toiovec(L, -1, cbd, &iov[niov])) {
+					lua_pop(L, 2);
+					msg_err("tcp request has bad data argument at pos %d", niov);
+					lua_pushboolean(L, FALSE);
+					g_free(iov);
+					g_free(cbd);
+
+					return 1;
+				}
+
+				total_out += iov[niov].iov_len;
+				niov++;
+
+				lua_pop(L, 1);
+			}
+		}
+
+		lua_pop(L, 1);
+	}
+	else {
+		return luaL_error(L, "tcp request has bad params");
+	}
+
+	if (resolver == NULL && cfg == NULL && task == NULL) {
+		g_free(cbd);
+		g_free(iov);
+
+		return luaL_error(L, "tcp request has bad params: one of "
+							 "{resolver,task,config} should be set");
+	}
+
+	cbd->task = task;
+
+	if (task) {
+		cbd->item = rspamd_symcache_get_cur_item(task);
+	}
+
+	cbd->cfg = cfg;
+	h = rspamd_random_uint64_fast();
+	rspamd_snprintf(cbd->tag, sizeof(cbd->tag), "%uxL", h);
+	cbd->handlers = g_queue_new();
+	cbd->hostname = g_strdup(host);
+
+	if (total_out > 0) {
+		struct lua_tcp_handler *wh;
+
+		wh = g_malloc0(sizeof(*wh));
+		wh->type = LUA_WANT_WRITE;
+		wh->h.w.iov = iov;
+		wh->h.w.iovlen = niov;
+		wh->h.w.total_bytes = total_out;
+		wh->h.w.pos = 0;
+		/* Cannot set write handler here */
+		wh->h.w.cbref = -1;
+
+		if (cbref != -1 && !do_read) {
+			/* We have write only callback */
+			wh->h.w.cbref = cbref;
+		}
+		else {
+			/* We have simple client callback */
+			wh->h.w.cbref = -1;
+		}
+
+		g_queue_push_tail(cbd->handlers, wh);
+	}
+
+	cbd->event_loop = event_loop;
+	cbd->fd = -1;
+	cbd->port = port;
+	cbd->ev.timeout = timeout;
+
+	if (ssl) {
+		cbd->flags |= LUA_TCP_FLAG_SSL;
+
+		if (ssl_noverify) {
+			cbd->flags |= LUA_TCP_FLAG_SSL_NOVERIFY;
+		}
+	}
+
+	if (do_read) {
+		cbd->in = g_byte_array_sized_new(8192);
+	}
+	else {
+		/* Save some space... */
+		cbd->in = g_byte_array_new();
+	}
+
+	if (partial) {
+		cbd->flags |= LUA_TCP_FLAG_PARTIAL;
+	}
+
+	if (do_shutdown) {
+		cbd->flags |= LUA_TCP_FLAG_SHUTDOWN;
+	}
+
+	if (do_read) {
+		struct lua_tcp_handler *rh;
+
+		rh = g_malloc0(sizeof(*rh));
+		rh->type = LUA_WANT_READ;
+		rh->h.r.cbref = cbref;
+		rh->h.r.stop_pattern = stop_pattern;
+		rh->h.r.plen = plen;
+		g_queue_push_tail(cbd->handlers, rh);
+	}
+
+	cbd->connect_cb = conn_cbref;
+	REF_INIT_RETAIN(cbd, lua_tcp_maybe_free);
+
+	if (up) {
+		cbd->up = rspamd_upstream_ref(up);
+	}
+
+	if (session) {
+		cbd->session = session;
+
+		if (rspamd_session_blocked(session)) {
+			lua_tcp_push_error(cbd, TRUE, "async session is the blocked state");
+			TCP_RELEASE(cbd);
+			cbd->item = NULL; /* To avoid decrease with no watcher */
+			lua_pushboolean(L, FALSE);
+
+			return 1;
+		}
+	}
+
+	if (cbd->up) {
+		/* Use upstream to get addr */
+		cbd->addr = rspamd_inet_address_copy(rspamd_upstream_addr_next(cbd->up), NULL);
+
+		/* Host is numeric IP, no need to resolve */
+		lua_tcp_register_watcher(cbd);
+
+		if (!lua_tcp_make_connection(cbd)) {
+			lua_tcp_push_error(cbd, TRUE, "cannot connect to the host: %s", host);
+			lua_pushboolean(L, FALSE);
+
+			rspamd_upstream_fail(cbd->up, true, "failed to connect");
+
+			/* No reset of the item as watcher has been registered */
+			TCP_RELEASE(cbd);
+
+			return 1;
+		}
+	}
+	else if (rspamd_parse_inet_address(&cbd->addr,
+									   host, strlen(host), RSPAMD_INET_ADDRESS_PARSE_DEFAULT)) {
+		rspamd_inet_address_set_port(cbd->addr, port);
+		/* Host is numeric IP, no need to resolve */
+		lua_tcp_register_watcher(cbd);
+
+		if (!lua_tcp_make_connection(cbd)) {
+			lua_tcp_push_error(cbd, TRUE, "cannot connect to the host: %s", host);
+			lua_pushboolean(L, FALSE);
+
+			/* No reset of the item as watcher has been registered */
+			TCP_RELEASE(cbd);
+
+			return 1;
+		}
+	}
+	else {
+		if (task == NULL) {
+			if (!rspamd_dns_resolver_request(resolver, session, NULL, lua_tcp_dns_handler, cbd,
+											 RDNS_REQUEST_A, host)) {
+				lua_tcp_push_error(cbd, TRUE, "cannot resolve host: %s", host);
+				lua_pushboolean(L, FALSE);
+				cbd->item = NULL; /* To avoid decrease with no watcher */
+				TCP_RELEASE(cbd);
+
+				return 1;
+			}
+			else {
+				lua_tcp_register_watcher(cbd);
+			}
+		}
+		else {
+			if (!rspamd_dns_resolver_request_task(task, lua_tcp_dns_handler, cbd,
+												  RDNS_REQUEST_A, host)) {
+				lua_tcp_push_error(cbd, TRUE, "cannot resolve host: %s", host);
+				lua_pushboolean(L, FALSE);
+				cbd->item = NULL; /* To avoid decrease with no watcher */
+
+				TCP_RELEASE(cbd);
+
+				return 1;
+			}
+			else {
+				lua_tcp_register_watcher(cbd);
+			}
+		}
+	}
+
+	lua_pushboolean(L, TRUE);
+	return 1;
+}
+
+/***
+ * @function rspamd_tcp.connect_sync({params})
+ * Creates new pseudo-synchronous connection to the specific address:port
+ *
+ * - `task`: rspamd task objects (implies `pool`, `session`, `ev_base` and `resolver` arguments)
+ * - `ev_base`: event base (if no task specified)
+ * - `resolver`: DNS resolver (no task)
+ * - `session`: events session (no task)
+ * - `config`: config (no task)
+ * - `host`: IP or name of the peer (required)
+ * - `port`: remote port to use
+ * - `timeout`: floating point value that specifies timeout for IO operations in **seconds**
+ * @return {boolean} true if request has been sent
+ */
+static gint
+lua_tcp_connect_sync(lua_State *L)
+{
+	LUA_TRACE_POINT;
+	GError *err = NULL;
+
+	gint64 port = -1;
+	gdouble timeout = default_tcp_timeout;
+	const gchar *host = NULL;
+	gint ret;
+	guint64 h;
+
+	struct rspamd_task *task = NULL;
+	struct rspamd_async_session *session = NULL;
+	struct rspamd_dns_resolver *resolver = NULL;
+	struct rspamd_config *cfg = NULL;
+	struct ev_loop *ev_base = NULL;
+	struct lua_tcp_cbdata *cbd;
+
+
+	int arguments_validated = rspamd_lua_parse_table_arguments(L, 1, &err,
+															   RSPAMD_LUA_PARSE_ARGUMENTS_DEFAULT,
+															   "task=U{task};session=U{session};resolver=U{resolver};ev_base=U{ev_base};"
+															   "*host=S;*port=I;timeout=D;config=U{config}",
+															   &task, &session, &resolver, &ev_base,
+															   &host, &port, &timeout, &cfg);
+
+	if (!arguments_validated) {
+		if (err) {
+			ret = luaL_error(L, "invalid arguments: %s", err->message);
+			g_error_free(err);
+
+			return ret;
+		}
+
+		return luaL_error(L, "invalid arguments");
+	}
+
+	if (0 > port || port > 65535) {
+		return luaL_error(L, "invalid port given (correct values: 1..65535)");
+	}
+
+	if (task == NULL && (cfg == NULL || ev_base == NULL || session == NULL)) {
+		return luaL_error(L, "invalid arguments: either task or config+ev_base+session should be set");
+	}
+
+	if (isnan(timeout)) {
+		/* rspamd_lua_parse_table_arguments() sets missing N field to zero */
+		timeout = default_tcp_timeout;
+	}
+
+	cbd = g_new0(struct lua_tcp_cbdata, 1);
+
+	if (task) {
+		static const gchar hexdigests[16] = "0123456789abcdef";
+
+		cfg = task->cfg;
+		ev_base = task->event_loop;
+		session = task->s;
+		/* Make a readable tag */
+		memcpy(cbd->tag, task->task_pool->tag.uid, sizeof(cbd->tag) - 2);
+		cbd->tag[sizeof(cbd->tag) - 2] = hexdigests[GPOINTER_TO_INT(cbd) & 0xf];
+		cbd->tag[sizeof(cbd->tag) - 1] = 0;
+	}
+	else {
+		h = rspamd_random_uint64_fast();
+		rspamd_snprintf(cbd->tag, sizeof(cbd->tag), "%uxL", h);
+	}
+
+	if (resolver == NULL) {
+		if (task) {
+			resolver = task->resolver;
+		}
+		else {
+			resolver = lua_tcp_global_resolver(ev_base, cfg);
+		}
+	}
+
+	cbd->task = task;
+	cbd->cfg = cfg;
+	cbd->thread = lua_thread_pool_get_running_entry(cfg->lua_thread_pool);
+
+
+	cbd->handlers = g_queue_new();
+
+	cbd->event_loop = ev_base;
+	cbd->flags |= LUA_TCP_FLAG_SYNC;
+	cbd->fd = -1;
+	cbd->port = (guint16) port;
+
+	cbd->in = g_byte_array_new();
+
+	cbd->connect_cb = -1;
+
+	REF_INIT_RETAIN(cbd, lua_tcp_maybe_free);
+
+	if (task) {
+		rspamd_mempool_add_destructor(task->task_pool, lua_tcp_sync_session_dtor, cbd);
+	}
+
+	struct lua_tcp_handler *wh;
+
+	wh = g_malloc0(sizeof(*wh));
+	wh->type = LUA_WANT_CONNECT;
+
+	g_queue_push_tail(cbd->handlers, wh);
+
+	if (session) {
+		cbd->session = session;
+
+		if (rspamd_session_blocked(session)) {
+			TCP_RELEASE(cbd);
+			lua_pushboolean(L, FALSE);
+			lua_pushliteral(L, "Session is being destroyed, requests are not allowed");
+
+			return 2;
+		}
+	}
+
+	if (rspamd_parse_inet_address(&cbd->addr,
+								  host, strlen(host), RSPAMD_INET_ADDRESS_PARSE_DEFAULT)) {
+		rspamd_inet_address_set_port(cbd->addr, (guint16) port);
+		/* Host is numeric IP, no need to resolve */
+		if (!lua_tcp_make_connection(cbd)) {
+			lua_pushboolean(L, FALSE);
+			lua_pushliteral(L, "Failed to initiate connection");
+
+			TCP_RELEASE(cbd);
+
+			return 2;
+		}
+	}
+	else {
+		if (task == NULL) {
+			if (!rspamd_dns_resolver_request(resolver, session, NULL, lua_tcp_dns_handler, cbd,
+											 RDNS_REQUEST_A, host)) {
+				lua_pushboolean(L, FALSE);
+				lua_pushliteral(L, "Failed to initiate dns request");
+
+				TCP_RELEASE(cbd);
+
+				return 2;
+			}
+			else {
+				lua_tcp_register_watcher(cbd);
+			}
+		}
+		else {
+			cbd->item = rspamd_symcache_get_cur_item(task);
+
+			if (!rspamd_dns_resolver_request_task(task, lua_tcp_dns_handler, cbd,
+												  RDNS_REQUEST_A, host)) {
+				cbd->item = NULL; /* We have not registered watcher */
+				lua_pushboolean(L, FALSE);
+				lua_pushliteral(L, "Failed to initiate dns request");
+				TCP_RELEASE(cbd);
+
+				return 2;
+			}
+			else {
+				lua_tcp_register_watcher(cbd);
+			}
+		}
+	}
+
+	return lua_thread_yield(cbd->thread, 0);
+}
+
+static gint
+lua_tcp_close(lua_State *L)
+{
+	LUA_TRACE_POINT;
+	struct lua_tcp_cbdata *cbd = lua_check_tcp(L, 1);
+
+	if (cbd == NULL) {
+		return luaL_error(L, "invalid arguments");
+	}
+
+	cbd->flags |= LUA_TCP_FLAG_FINISHED;
+
+	if (cbd->ssl_conn) {
+		/* TODO: postpone close in case ssl is used ! */
+		rspamd_ssl_connection_free(cbd->ssl_conn);
+		cbd->ssl_conn = NULL;
+	}
+
+	if (cbd->fd != -1) {
+		rspamd_ev_watcher_stop(cbd->event_loop, &cbd->ev);
+		close(cbd->fd);
+		cbd->fd = -1;
+	}
+
+	if (cbd->addr) {
+		rspamd_inet_address_free(cbd->addr);
+		cbd->addr = NULL;
+	}
+
+	if (cbd->up) {
+		rspamd_upstream_unref(cbd->up);
+		cbd->up = NULL;
+	}
+	/* Do not release refcount as it will be handled elsewhere */
+	/* TCP_RELEASE (cbd); */
+
+	return 0;
+}
+
+static gint
+lua_tcp_add_read(lua_State *L)
+{
+	LUA_TRACE_POINT;
+	struct lua_tcp_cbdata *cbd = lua_check_tcp(L, 1);
+	struct lua_tcp_handler *rh;
+	gchar *stop_pattern = NULL;
+	const gchar *p;
+	gsize plen = 0;
+	gint cbref = -1;
+
+	if (cbd == NULL) {
+		return luaL_error(L, "invalid arguments");
+	}
+
+	if (lua_type(L, 2) == LUA_TFUNCTION) {
+		lua_pushvalue(L, 2);
+		cbref = luaL_ref(L, LUA_REGISTRYINDEX);
+	}
+
+	if (lua_type(L, 3) == LUA_TSTRING) {
+		p = lua_tolstring(L, 3, &plen);
+
+		if (p && plen > 0) {
+			stop_pattern = g_malloc(plen);
+			memcpy(stop_pattern, p, plen);
+		}
+	}
+
+	rh = g_malloc0(sizeof(*rh));
+	rh->type = LUA_WANT_READ;
+	rh->h.r.cbref = cbref;
+	rh->h.r.stop_pattern = stop_pattern;
+	rh->h.r.plen = plen;
+	msg_debug_tcp("added read event, cbref: %d", cbref);
+
+	g_queue_push_tail(cbd->handlers, rh);
+
+	return 0;
+}
+
+static gint
+lua_tcp_add_write(lua_State *L)
+{
+	LUA_TRACE_POINT;
+	struct lua_tcp_cbdata *cbd = lua_check_tcp(L, 1);
+	struct lua_tcp_handler *wh;
+	gint cbref = -1, tp;
+	struct iovec *iov = NULL;
+	guint niov = 0, total_out = 0;
+
+	if (cbd == NULL) {
+		return luaL_error(L, "invalid arguments");
+	}
+
+	if (lua_type(L, 2) == LUA_TFUNCTION) {
+		lua_pushvalue(L, 2);
+		cbref = luaL_ref(L, LUA_REGISTRYINDEX);
+	}
+
+	tp = lua_type(L, 3);
+	if (tp == LUA_TSTRING || tp == LUA_TUSERDATA) {
+		iov = g_malloc(sizeof(*iov));
+		niov = 1;
+
+		if (!lua_tcp_arg_toiovec(L, 3, cbd, iov)) {
+			msg_err("tcp request has bad data argument");
+			lua_pushboolean(L, FALSE);
+			g_free(iov);
+
+			return 1;
+		}
+
+		total_out = iov[0].iov_len;
+	}
+	else if (tp == LUA_TTABLE) {
+		/* Count parts */
+		lua_pushvalue(L, 3);
+
+		lua_pushnil(L);
+		while (lua_next(L, -2) != 0) {
+			niov++;
+			lua_pop(L, 1);
+		}
+
+		iov = g_malloc(sizeof(*iov) * niov);
+		lua_pushnil(L);
+		niov = 0;
+
+		while (lua_next(L, -2) != 0) {
+			if (!lua_tcp_arg_toiovec(L, -1, cbd, &iov[niov])) {
+				lua_pop(L, 2);
+				msg_err("tcp request has bad data argument at pos %d", niov);
+				lua_pushboolean(L, FALSE);
+				g_free(iov);
+				g_free(cbd);
+
+				return 1;
+			}
+
+			total_out += iov[niov].iov_len;
+			niov++;
+
+			lua_pop(L, 1);
+		}
+
+		lua_pop(L, 1);
+	}
+
+	wh = g_malloc0(sizeof(*wh));
+	wh->type = LUA_WANT_WRITE;
+	wh->h.w.iov = iov;
+	wh->h.w.iovlen = niov;
+	wh->h.w.total_bytes = total_out;
+	wh->h.w.pos = 0;
+	/* Cannot set write handler here */
+	wh->h.w.cbref = cbref;
+	msg_debug_tcp("added write event, cbref: %d", cbref);
+
+	g_queue_push_tail(cbd->handlers, wh);
+	lua_pushboolean(L, TRUE);
+
+	return 1;
+}
+
+static gint
+lua_tcp_shift_callback(lua_State *L)
+{
+	LUA_TRACE_POINT;
+	struct lua_tcp_cbdata *cbd = lua_check_tcp(L, 1);
+
+	if (cbd == NULL) {
+		return luaL_error(L, "invalid arguments");
+	}
+
+	lua_tcp_shift_handler(cbd);
+	lua_tcp_plan_handler_event(cbd, TRUE, TRUE);
+
+	return 0;
+}
+
+static struct lua_tcp_cbdata *
+lua_check_sync_tcp(lua_State *L, gint pos)
+{
+	void *ud = rspamd_lua_check_udata(L, pos, "rspamd{tcp_sync}");
+	luaL_argcheck(L, ud != NULL, pos, "'tcp' expected");
+	return ud ? *((struct lua_tcp_cbdata **) ud) : NULL;
+}
+
+static int
+lua_tcp_sync_close(lua_State *L)
+{
+	LUA_TRACE_POINT;
+	struct lua_tcp_cbdata *cbd = lua_check_sync_tcp(L, 1);
+
+	if (cbd == NULL) {
+		return luaL_error(L, "invalid arguments [self is not rspamd{tcp_sync}]");
+	}
+	cbd->flags |= LUA_TCP_FLAG_FINISHED;
+
+	if (cbd->fd != -1) {
+		rspamd_ev_watcher_stop(cbd->event_loop, &cbd->ev);
+		close(cbd->fd);
+		cbd->fd = -1;
+	}
+
+	return 0;
+}
+
+static void
+lua_tcp_sync_session_dtor(gpointer ud)
+{
+	struct lua_tcp_cbdata *cbd = ud;
+	cbd->flags |= LUA_TCP_FLAG_FINISHED;
+
+	if (cbd->fd != -1) {
+		msg_debug("closing sync TCP connection");
+		rspamd_ev_watcher_stop(cbd->event_loop, &cbd->ev);
+		close(cbd->fd);
+		cbd->fd = -1;
+	}
+
+	/* Task is gone, we should not try use it anymore */
+	cbd->task = NULL;
+
+	/* All events are removed when task is done, we should not refer them */
+	cbd->async_ev = NULL;
+}
+
+static int
+lua_tcp_sync_read_once(lua_State *L)
+{
+	LUA_TRACE_POINT;
+	struct lua_tcp_cbdata *cbd = lua_check_sync_tcp(L, 1);
+	struct lua_tcp_handler *rh;
+
+	if (cbd == NULL) {
+		return luaL_error(L, "invalid arguments [self is not rspamd{tcp_sync}]");
+	}
+
+	struct thread_entry *thread = lua_thread_pool_get_running_entry(cbd->cfg->lua_thread_pool);
+
+	rh = g_malloc0(sizeof(*rh));
+	rh->type = LUA_WANT_READ;
+	rh->h.r.cbref = -1;
+
+	msg_debug_tcp("added read sync event, thread: %p", thread);
+
+	g_queue_push_tail(cbd->handlers, rh);
+	lua_tcp_plan_handler_event(cbd, TRUE, TRUE);
+
+	TCP_RETAIN(cbd);
+
+	return lua_thread_yield(thread, 0);
+}
+
+static int
+lua_tcp_sync_write(lua_State *L)
+{
+	LUA_TRACE_POINT;
+	struct lua_tcp_cbdata *cbd = lua_check_sync_tcp(L, 1);
+	struct lua_tcp_handler *wh;
+	gint tp;
+	struct iovec *iov = NULL;
+	guint niov = 0;
+	gsize total_out = 0;
+
+	if (cbd == NULL) {
+		return luaL_error(L, "invalid arguments [self is not rspamd{tcp_sync}]");
+	}
+
+	struct thread_entry *thread = lua_thread_pool_get_running_entry(cbd->cfg->lua_thread_pool);
+
+	tp = lua_type(L, 2);
+	if (tp == LUA_TSTRING || tp == LUA_TUSERDATA) {
+		iov = g_malloc(sizeof(*iov));
+		niov = 1;
+
+		if (!lua_tcp_arg_toiovec(L, 2, cbd, iov)) {
+			msg_err("tcp request has bad data argument");
+			g_free(iov);
+			g_free(cbd);
+
+			return luaL_error(L, "invalid arguments second parameter (data) is expected to be either string or rspamd{text}");
+		}
+
+		total_out = iov[0].iov_len;
+	}
+	else if (tp == LUA_TTABLE) {
+		/* Count parts */
+		lua_pushvalue(L, 3);
+
+		lua_pushnil(L);
+		while (lua_next(L, -2) != 0) {
+			niov++;
+			lua_pop(L, 1);
+		}
+
+		iov = g_malloc(sizeof(*iov) * niov);
+		lua_pushnil(L);
+		niov = 0;
+
+		while (lua_next(L, -2) != 0) {
+			if (!lua_tcp_arg_toiovec(L, -1, cbd, &iov[niov])) {
+				msg_err("tcp request has bad data argument at pos %d", niov);
+				g_free(iov);
+				g_free(cbd);
+
+				return luaL_error(L, "invalid arguments second parameter (data) is expected to be either string or rspamd{text}");
+			}
+
+			total_out += iov[niov].iov_len;
+			niov++;
+
+			lua_pop(L, 1);
+		}
+
+		lua_pop(L, 1);
+	}
+
+	wh = g_malloc0(sizeof(*wh));
+	wh->type = LUA_WANT_WRITE;
+	wh->h.w.iov = iov;
+	wh->h.w.iovlen = niov;
+	wh->h.w.total_bytes = total_out;
+	wh->h.w.pos = 0;
+	wh->h.w.cbref = -1;
+	msg_debug_tcp("added sync write event, thread: %p", thread);
+
+	g_queue_push_tail(cbd->handlers, wh);
+	lua_tcp_plan_handler_event(cbd, TRUE, TRUE);
+
+	TCP_RETAIN(cbd);
+
+	return lua_thread_yield(thread, 0);
+}
+
+static gint
+lua_tcp_sync_eof(lua_State *L)
+{
+	LUA_TRACE_POINT;
+	struct lua_tcp_cbdata *cbd = lua_check_sync_tcp(L, 1);
+	if (cbd == NULL) {
+		return luaL_error(L, "invalid arguments [self is not rspamd{tcp_sync}]");
+	}
+
+	lua_pushboolean(L, cbd->eof);
+
+	return 1;
+}
+
+static gint
+lua_tcp_sync_shutdown(lua_State *L)
+{
+	LUA_TRACE_POINT;
+	struct lua_tcp_cbdata *cbd = lua_check_sync_tcp(L, 1);
+	if (cbd == NULL) {
+		return luaL_error(L, "invalid arguments [self is not rspamd{tcp_sync}]");
+	}
+
+	shutdown(cbd->fd, SHUT_WR);
+
+	return 0;
+}
+
+static gint
+lua_tcp_starttls(lua_State *L)
+{
+	LUA_TRACE_POINT;
+	struct lua_tcp_cbdata *cbd = lua_check_tcp(L, 1);
+	gpointer ssl_ctx;
+	gboolean verify_peer;
+
+	if (cbd == NULL || cbd->ssl_conn != NULL) {
+		return luaL_error(L, "invalid arguments");
+	}
+
+	if (cbd->flags & LUA_TCP_FLAG_SSL_NOVERIFY) {
+		ssl_ctx = cbd->cfg->libs_ctx->ssl_ctx_noverify;
+		verify_peer = FALSE;
+	}
+	else {
+		ssl_ctx = cbd->cfg->libs_ctx->ssl_ctx;
+		verify_peer = TRUE;
+	}
+
+	cbd->ssl_conn = rspamd_ssl_connection_new(ssl_ctx,
+											  cbd->event_loop,
+											  verify_peer,
+											  cbd->tag);
+
+	if (!rspamd_ssl_connect_fd(cbd->ssl_conn, cbd->fd, cbd->hostname, &cbd->ev,
+							   cbd->ev.timeout, lua_tcp_handler, lua_tcp_ssl_on_error, cbd)) {
+		lua_tcp_push_error(cbd, TRUE, "ssl connection failed: %s",
+						   strerror(errno));
+	}
+
+	return 0;
+}
+
+static gint
+lua_tcp_sync_gc(lua_State *L)
+{
+	struct lua_tcp_cbdata *cbd = lua_check_sync_tcp(L, 1);
+	if (!cbd) {
+		return luaL_error(L, "invalid arguments [self is not rspamd{tcp_sync}]");
+	}
+
+	lua_tcp_maybe_free(cbd);
+	lua_tcp_fin(cbd);
+
+	return 0;
+}
+
+static gint
+lua_load_tcp(lua_State *L)
+{
+	lua_newtable(L);
+	luaL_register(L, NULL, tcp_libf);
+
+	return 1;
+}
+
+void luaopen_tcp(lua_State *L)
+{
+	rspamd_lua_add_preload(L, "rspamd_tcp", lua_load_tcp);
+	rspamd_lua_new_class(L, "rspamd{tcp}", tcp_libm);
+	rspamd_lua_new_class(L, "rspamd{tcp_sync}", tcp_sync_libm);
+	lua_pop(L, 1);
+}