* Fix DNS PTR resolving

* Add ability to resolve ip in once_received plugin to avoid temporary DNS fails of SMTP resolving

src/dns.c

@@ -422,18 +422,15 @@ format_dns_name (struct rspamd_dns_request *req, const gchar *name, guint namele
 }
 
 static void
-make_ptr_req (struct rspamd_dns_request *req, struct in_addr addr)
+make_ptr_req (struct rspamd_dns_request *req, struct in_addr *addr)
 {
 	gchar                           ipbuf[sizeof("255.255.255.255.in-addr.arpa")];
-	guint32 a = ntohl (addr.s_addr), r;
-	guint16 *p;
+	guint32                         r;
+	guint16                        *p;
+	guint8                         *addr_p = (guint8 *)&addr->s_addr;
 
 	r = rspamd_snprintf (ipbuf, sizeof(ipbuf), "%d.%d.%d.%d.in-addr.arpa",
-			(gint)(guint8)((a	) & 0xff),
-			(gint)(guint8)((a>>8 ) & 0xff),
-			(gint)(guint8)((a>>16) & 0xff),
-			(gint)(guint8)((a>>24) & 0xff));
-	
+			addr_p[3], addr_p[2], addr_p[1], addr_p[0]);
 	allocate_packet (req, r);
 	make_dns_header (req);
 	format_dns_name (req, ipbuf, r);
@@ -1143,7 +1140,7 @@ make_dns_request (struct rspamd_dns_resolver *resolver,
 {
 	va_list args;
 	struct rspamd_dns_request *req;
-	struct in_addr addr;
+	struct in_addr *addr;
 	const gchar *name, *service, *proto;
 	gint r;
 	struct dns_header *header;
@@ -1164,7 +1161,7 @@ make_dns_request (struct rspamd_dns_resolver *resolver,
 	va_start (args, type);
 	switch (type) {
 		case DNS_REQUEST_PTR:
-			addr = va_arg (args, struct in_addr);
+			addr = va_arg (args, struct in_addr *);
 			make_ptr_req (req, addr);
 			break;
 		case DNS_REQUEST_MX:

src/lua/lua_task.c

@@ -668,7 +668,8 @@ lua_task_resolve_dns_ptr (lua_State * L)
 			msg_info ("invalid parameters passed to function");
 			return 0;
 		}
-		if (make_dns_request (task->resolver, task->s, task->task_pool, lua_dns_callback, (void *)cd, DNS_REQUEST_PTR, ina)) {
+		if (make_dns_request (task->resolver, task->s, task->task_pool,
+				lua_dns_callback, (void *)cd, DNS_REQUEST_PTR, ina)) {
 			task->dns_requests ++;
 			task->save.saved++;
 		}

src/plugins/lua/once_received.lua

@@ -6,6 +6,32 @@ local symbol_strict = nil
 local bad_hosts = {}
 local good_hosts = {}
 
+function recv_dns_cb(task, to_resolve, results, err)
+	if not results then
+		task:insert_result(symbol_strict, 1)
+	else
+		rspamd_logger.info(string.format('SMTP resolver failed to resolve: %s is %s', to_resolve, results[1]))
+		local i = true
+		for _,h in ipairs(bad_hosts) do
+			if string.find(results[1], h) then
+				-- Check for good hostname
+				if good_hosts then
+					for _,gh in ipairs(good_hosts) do
+						if string.find(results[1], gh) then
+							i = false
+							break
+						end
+					end
+				end
+				if i then
+					task:insert_result(symbol_strict, 1, h)
+					return
+				end
+			end
+		end
+	end
+end
+
 function check_quantity_received (task)
 	local recvh = task:get_received_headers()
 	if table.maxn(recvh) <= 1 then
@@ -18,7 +44,12 @@ function check_quantity_received (task)
             end
 			-- Unresolved host
 			if not r['real_hostname'] or string.lower(r['real_hostname']) == 'unknown' or string.match(r['real_hostname'], '^%d+%.%d+%.%d+%.%d+$') then
-				task:insert_result(symbol_strict, 1)
+				if r['real_ip'] then
+					-- Try to resolve it again
+					task:resolve_dns_ptr(r['real_ip'], 'recv_dns_cb')
+				else
+					task:insert_result(symbol_strict, 1)
+				end
                 return
 			end
 
@@ -69,9 +100,17 @@ if opts then
 					rspamd_config:register_virtual_symbol(symbol_strict, 1.0)
 				end
 			elseif n == 'bad_host' then
-			    bad_hosts = v
+				if type(v) == 'string' then
+			    	bad_hosts[1] = v
+				else
+					bad_hosts = v
+				end
 			elseif n == 'good_host' then
-			    good_hosts = v
+				if type(v) == 'string' then
+			    	good_hosts[1] = v
+				else
+					good_hosts = v
+				end
 		    end
 	    end
 

src/smtp.c

@@ -690,7 +690,8 @@ accept_socket (gint fd, short what, void *arg)
 	/* Set up async session */
 	session->s = new_async_session (session->pool, free_smtp_session, session);
 	session->state = SMTP_STATE_RESOLVE_REVERSE;
-	if (! make_dns_request (session->resolver, session->s, session->pool, smtp_dns_cb, session, DNS_REQUEST_PTR, session->client_addr)) {
+	if (! make_dns_request (session->resolver, session->s, session->pool,
+			smtp_dns_cb, session, DNS_REQUEST_PTR, &session->client_addr)) {
 		msg_err ("cannot resolve %s", inet_ntoa (session->client_addr));
 		g_free (session);
 		close (nfd);