+
+function attempt_connection(host_session, err)
+ local from_host, to_host = host_session.from_host, host_session.to_host;
+ local conn, handler = socket.tcp()
+
+ local connect_host, connect_port = idna_to_ascii(to_host), 5269;
+
+ if not err then -- This is our first attempt
+ local answer = dns.lookup("_xmpp-server._tcp."..connect_host..".", "SRV");
+
+ if answer then
+ log("debug", to_host.." has SRV records, handling...");
+ local srv_hosts = {};
+ host_session.srv_hosts = srv_hosts;
+ for _, record in ipairs(answer) do
+ t_insert(srv_hosts, record.srv);
+ end
+ t_sort(srv_hosts, compare_srv_priorities);
+
+ local srv_choice = srv_hosts[1];
+ host_session.srv_choice = 1;
+ if srv_choice then
+ connect_host, connect_port = srv_choice.target or to_host, srv_choice.port or connect_port;
+ log("debug", "Best record found, will connect to %s:%d", connect_host, connect_port);
+ end
+ end
+ elseif host_session.srv_hosts and #host_session.srv_hosts > host_session.srv_choice then -- Not our first attempt, and we also have SRV
+ host_session.srv_choice = host_session.srv_choice + 1;
+ local srv_choice = host_session.srv_hosts[host_session.srv_choice];
+ connect_host, connect_port = srv_choice.target or to_host, srv_choice.port or connect_port;
+ host_session.log("debug", "Connection failed (%s). Attempt #%d: This time to %s:%d", tostring(err), host_session.srv_choice, connect_host, connect_port);
+ else
+ host_session.log("debug", "Out of connection options, can't connect to %s", tostring(host_session.to_host));
+ -- We're out of options
+ return false;
+ end
+
+ -- Ok, we're going to try to connect
+ conn:settimeout(0);
+ local success, err = conn:connect(connect_host, connect_port);
+ if not success and err ~= "timeout" then
+ log("warn", "s2s connect() failed: %s", err);
+ return false;
+ end
+
+ local cl = connlisteners_get("xmppserver");
+ conn = wrapclient(conn, connect_host, connect_port, cl, cl.default_mode or 1, hosts[from_host].ssl_ctx, false );
+ host_session.conn = conn;
+
+ -- Register this outgoing connection so that xmppserver_listener knows about it
+ -- otherwise it will assume it is a new incoming connection
+ cl.register_outgoing(conn, host_session);
+
+ local w = conn.write;
+ host_session.sends2s = function (t) log("debug", "sending: %s", tostring(t)); w(tostring(t)); end
+
+ conn.write(format([[<stream:stream xmlns='jabber:server' xmlns:db='jabber:server:dialback' xmlns:stream='http://etherx.jabber.org/streams' from='%s' to='%s' version='1.0'>]], from_host, to_host));
+ return true;
+end
+