--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mod_s2s_keepalive/mod_s2s_keepalive.lua	Fri Jul 12 01:28:48 2013 +0200
@@ -0,0 +1,42 @@
+local st = require "util.stanza";
+
+local keepalive_servers = module:get_option_set("keepalive_servers");
+local keepalive_interval = module:get_option_number("keepalive_interval", 60);
+
+local host = module.host;
+
+local function send_pings()
+	for remote_domain, session in pairs(hosts[host].s2sout) do
+		if session.type == "s2sout" -- as opposed to _unauthed
+		and (not(keepalive_servers) or keepalive_servers:contains(remote_domain)) then
+			session.sends2s(st.iq({ to = remote_domain, type = "get", from = host, id = "keepalive" })
+				:tag("ping", { xmlns = "urn:xmpp:ping" })
+			);
+			-- Note: We don't actually check if this comes back.
+		end
+	end
+
+	for session in pairs(prosody.incoming_s2s) do
+		if session.type == "s2sin" -- as opposed to _unauthed
+		and (not(keepalive_servers) or keepalive_servers:contains(session.from_host)) then
+			session.conn:send " ";
+			-- If the connection is dead, this should make it time out.
+		end
+	end
+	return keepalive_interval;
+end
+
+if module.add_timer then -- 0.9
+	module:add_timer(keepalive_interval, send_pings);
+else -- 0.8
+	local timer = require "util.timer";
+	local unloaded;
+	timer.add_task(keepalive_interval, function()
+		if not unloaded then
+			return send_pings()
+		end
+	end);
+	function module.unload()
+		unloaded = true
+	end
+end