plugins/mod_bosh.lua

-- Prosody IM

-- Copyright (C) 2008-2010 Matthew Wild

-- Copyright (C) 2008-2010 Waqas Hussain

-- 

-- This project is MIT/X11 licensed. Please see the

-- COPYING file in the source package for more information.

--

module.host = "*" -- Global module

local hosts = _G.hosts;

local lxp = require "lxp";

local new_xmpp_stream = require "util.xmppstream".new;

local httpserver = require "net.httpserver";

local sm = require "core.sessionmanager";

local sm_destroy_session = sm.destroy_session;

local new_uuid = require "util.uuid".generate;

local fire_event = prosody.events.fire_event;

local core_process_stanza = core_process_stanza;

local st = require "util.stanza";

local logger = require "util.logger";

local log = logger.init("mod_bosh");

local timer = require "util.timer";

local xmlns_streams = "http://etherx.jabber.org/streams";

local xmlns_xmpp_streams = "urn:ietf:params:xml:ns:xmpp-streams";

local xmlns_bosh = "http://jabber.org/protocol/httpbind"; -- (hard-coded into a literal in session.send)

local stream_callbacks = {

	stream_ns = xmlns_bosh, stream_tag = "body", default_ns = "jabber:client" };

local BOSH_DEFAULT_HOLD = tonumber(module:get_option("bosh_default_hold")) or 1;

local BOSH_DEFAULT_INACTIVITY = tonumber(module:get_option("bosh_max_inactivity")) or 60;

local BOSH_DEFAULT_POLLING = tonumber(module:get_option("bosh_max_polling")) or 5;

local BOSH_DEFAULT_REQUESTS = tonumber(module:get_option("bosh_max_requests")) or 2;

local consider_bosh_secure = module:get_option_boolean("consider_bosh_secure");

local default_headers = { ["Content-Type"] = "text/xml; charset=utf-8" };

local cross_domain = module:get_option("cross_domain_bosh");

if cross_domain then

	default_headers["Access-Control-Allow-Methods"] = "GET, POST, OPTIONS";

	default_headers["Access-Control-Allow-Headers"] = "Content-Type";

	default_headers["Access-Control-Max-Age"] = "7200";

	if cross_domain == true then

		default_headers["Access-Control-Allow-Origin"] = "*";

	elseif type(cross_domain) == "table" then

		cross_domain = table.concat(cross_domain, ", ");

	end

	if type(cross_domain) == "string" then

		default_headers["Access-Control-Allow-Origin"] = cross_domain;

	end

end

local trusted_proxies = module:get_option_set("trusted_proxies", {"127.0.0.1"})._items;

local function get_ip_from_request(request)

	local ip = request.handler:ip();

	local forwarded_for = request.headers["x-forwarded-for"];

	if forwarded_for then

		forwarded_for = forwarded_for..", "..ip;

		for forwarded_ip in forwarded_for:gmatch("[^%s,]+") do

			if not trusted_proxies[forwarded_ip] then

				ip = forwarded_ip;

			end

		end

	end

	return ip;

end

local t_insert, t_remove, t_concat = table.insert, table.remove, table.concat;

local os_time = os.time;

local sessions = {};

local inactive_sessions = {}; -- Sessions which have no open requests

-- Used to respond to idle sessions (those with waiting requests)

local waiting_requests = {};

function on_destroy_request(request)

	waiting_requests[request] = nil;

	local session = sessions[request.sid];

	if session then

		local requests = session.requests;

		for i,r in ipairs(requests) do

			if r == request then

				t_remove(requests, i);

				break;

			end

		end

		-- If this session now has no requests open, mark it as inactive

		if #requests == 0 and session.bosh_max_inactive and not inactive_sessions[session] then

			inactive_sessions[session] = os_time();

			(session.log or log)("debug", "BOSH session marked as inactive at %d", inactive_sessions[session]);

		end

	end

end

function handle_request(method, body, request)

	if (not body) or request.method ~= "POST" then

		if request.method == "OPTIONS" then

			local headers = {};

			for k,v in pairs(default_headers) do headers[k] = v; end

			headers["Content-Type"] = nil;

			return { headers = headers, body = "" };

		else

			return "<html><body>You really don't look like a BOSH client to me... what do you want?</body></html>";

		end

	end

	if not method then

		log("debug", "Request %s suffered error %s", tostring(request.id), body);

		return;

	end

	--log("debug", "Handling new request %s: %s\n----------", request.id, tostring(body));

	request.notopen = true;

	request.log = log;

	request.on_destroy = on_destroy_request;

	local stream = new_xmpp_stream(request, stream_callbacks);

	-- stream:feed() calls the stream_callbacks, so all stanzas in

	-- the body are processed in this next line before it returns.

	stream:feed(body);

	local session = sessions[request.sid];

	if session then

		local r = session.requests;

		log("debug", "Session %s has %d out of %d requests open", request.sid, #r, session.bosh_hold);

		log("debug", "and there are %d things in the send_buffer", #session.send_buffer);

		if #r > session.bosh_hold then

			-- We are holding too many requests, send what's in the buffer,

			log("debug", "We are holding too many requests, so...");

			if #session.send_buffer > 0 then

				log("debug", "...sending what is in the buffer")

				session.send(t_concat(session.send_buffer));

				session.send_buffer = {};

			else

				-- or an empty response

				log("debug", "...sending an empty response");

				session.send("");

			end

		elseif #session.send_buffer > 0 then

			log("debug", "Session has data in the send buffer, will send now..");

			local resp = t_concat(session.send_buffer);

			session.send_buffer = {};

			session.send(resp);

		end

		if not request.destroyed then

			-- We're keeping this request open, to respond later

			log("debug", "Have nothing to say, so leaving request unanswered for now");

			if session.bosh_wait then

				request.reply_before = os_time() + session.bosh_wait;

				waiting_requests[request] = true;

			end

			if inactive_sessions[session] then

				-- Session was marked as inactive, since we have

				-- a request open now, unmark it

				inactive_sessions[session] = nil;

			end

		end

		return true; -- Inform httpserver we shall reply later

	end

end

local function bosh_reset_stream(session) session.notopen = true; end

local stream_xmlns_attr = { xmlns = "urn:ietf:params:xml:ns:xmpp-streams" };

local function bosh_close_stream(session, reason)

	(session.log or log)("info", "BOSH client disconnected");

	local close_reply = st.stanza("body", { xmlns = xmlns_bosh, type = "terminate",

		["xmlns:streams"] = xmlns_streams });

	if reason then

		close_reply.attr.condition = "remote-stream-error";

		if type(reason) == "string" then -- assume stream error

			close_reply:tag("stream:error")

				:tag(reason, {xmlns = xmlns_xmpp_streams});

		elseif type(reason) == "table" then

			if reason.condition then

				close_reply:tag("stream:error")

					:tag(reason.condition, stream_xmlns_attr):up();

				if reason.text then

					close_reply:tag("text", stream_xmlns_attr):text(reason.text):up();

				end

				if reason.extra then

					close_reply:add_child(reason.extra);

				end

			elseif reason.name then -- a stanza

				close_reply = reason;

			end

		end

		log("info", "Disconnecting client, <stream:error> is: %s", tostring(close_reply));

	end

	local session_close_response = { headers = default_headers, body = tostring(close_reply) };

	--FIXME: Quite sure we shouldn't reply to all requests with the error

	for _, held_request in ipairs(session.requests) do

		held_request:send(session_close_response);

		held_request:destroy();

	end

	sessions[session.sid]  = nil;

	sm_destroy_session(session);

end

function stream_callbacks.streamopened(request, attr)

	log("debug", "BOSH body open (sid: %s)", attr.sid);

	local sid = attr.sid

	if not sid then

		-- New session request

		request.notopen = nil; -- Signals that we accept this opening tag

		-- TODO: Sanity checks here (rid, to, known host, etc.)

		if not hosts[attr.to] then

			-- Unknown host

			log("debug", "BOSH client tried to connect to unknown host: %s", tostring(attr.to));

			local close_reply = st.stanza("body", { xmlns = xmlns_bosh, type = "terminate",

				["xmlns:streams"] = xmlns_streams, condition = "host-unknown" });

			request:send(tostring(close_reply));

			return;

		end

		-- New session

		sid = new_uuid();

		local session = {

			type = "c2s_unauthed", conn = {}, sid = sid, rid = tonumber(attr.rid), host = attr.to,

			bosh_version = attr.ver, bosh_wait = attr.wait, streamid = sid,

			bosh_hold = BOSH_DEFAULT_HOLD, bosh_max_inactive = BOSH_DEFAULT_INACTIVITY,

			requests = { }, send_buffer = {}, reset_stream = bosh_reset_stream,

			close = bosh_close_stream, dispatch_stanza = core_process_stanza,

			log = logger.init("bosh"..sid),	secure = consider_bosh_secure or request.secure,

			ip = get_ip_from_request(request);

		};

		sessions[sid] = session;

		session.log("debug", "BOSH session created for request from %s", session.ip);

		log("info", "New BOSH session, assigned it sid '%s'", sid);

		local r, send_buffer = session.requests, session.send_buffer;

		local response = { headers = default_headers }

		function session.send(s)

			-- We need to ensure that outgoing stanzas have the jabber:client xmlns

			if s.attr and not s.attr.xmlns then

				s = st.clone(s);

				s.attr.xmlns = "jabber:client";

			end

			--log("debug", "Sending BOSH data: %s", tostring(s));

			local oldest_request = r[1];

			if oldest_request then

				log("debug", "We have an open request, so sending on that");

				response.body = t_concat{"<body xmlns='http://jabber.org/protocol/httpbind' sid='", sid, "' xmlns:stream = 'http://etherx.jabber.org/streams'>", tostring(s), "</body>" };

				oldest_request:send(response);

				--log("debug", "Sent");

				if oldest_request.stayopen then

					if #r>1 then

						-- Move front request to back

						t_insert(r, oldest_request);

						t_remove(r, 1);

					end

				else

					log("debug", "Destroying the request now...");

					oldest_request:destroy();

				end

			elseif s ~= "" then

				log("debug", "Saved to send buffer because there are %d open requests", #r);

				-- Hmm, no requests are open :(

				t_insert(session.send_buffer, tostring(s));

				log("debug", "There are now %d things in the send_buffer", #session.send_buffer);

			end

		end

		-- Send creation response

		local features = st.stanza("stream:features");

		hosts[session.host].events.fire_event("stream-features", { origin = session, features = features });

		fire_event("stream-features", session, features);

		--xmpp:version='1.0' xmlns:xmpp='urn:xmpp:xbosh'

		local response = st.stanza("body", { xmlns = xmlns_bosh,

			wait = attr.wait,

			inactivity = tostring(BOSH_DEFAULT_INACTIVITY),

			polling = tostring(BOSH_DEFAULT_POLLING),

			requests = tostring(BOSH_DEFAULT_REQUESTS),

			hold = tostring(session.bosh_hold),

			sid = sid, authid = sid,

			ver  = '1.6', from = session.host,

			secure = 'true', ["xmpp:version"] = "1.0",

			["xmlns:xmpp"] = "urn:xmpp:xbosh",

			["xmlns:stream"] = "http://etherx.jabber.org/streams"

		}):add_child(features);

		request:send{ headers = default_headers, body = tostring(response) };

		request.sid = sid;

		return;

	end

	local session = sessions[sid];

	if not session then

		-- Unknown sid

		log("info", "Client tried to use sid '%s' which we don't know about", sid);

		request:send{ headers = default_headers, body = tostring(st.stanza("body", { xmlns = xmlns_bosh, type = "terminate", condition = "item-not-found" })) };

		request.notopen = nil;

		return;

	end

	if session.rid then

		local rid = tonumber(attr.rid);

		local diff = rid - session.rid;

		if diff > 1 then

			session.log("warn", "rid too large (means a request was lost). Last rid: %d New rid: %s", session.rid, attr.rid);

		elseif diff <= 0 then

			-- Repeated, ignore

			session.log("debug", "rid repeated (on request %s), ignoring: %s (diff %d)", request.id, session.rid, diff);

			request.notopen = nil;

			request.ignore = true;

			request.sid = sid;

			t_insert(session.requests, request);

			return;

		end

		session.rid = rid;

	end

	if attr.type == "terminate" then

		-- Client wants to end this session

		session:close();

		request.notopen = nil;

		return;

	end

	if session.notopen then

		local features = st.stanza("stream:features");

		hosts[session.host].events.fire_event("stream-features", { origin = session, features = features });

		fire_event("stream-features", session, features);

		session.send(features);

		session.notopen = nil;

	end

	request.notopen = nil; -- Signals that we accept this opening tag

	t_insert(session.requests, request);

	request.sid = sid;

end

function stream_callbacks.handlestanza(request, stanza)

	if request.ignore then return; end

	log("debug", "BOSH stanza received: %s\n", stanza:top_tag());

	local session = sessions[request.sid];

	if session then

		if stanza.attr.xmlns == xmlns_bosh then

			stanza.attr.xmlns = nil;

		end

		core_process_stanza(session, stanza);

	end

end

function stream_callbacks.error(request, error)

	log("debug", "Error parsing BOSH request payload; %s", error);

	if not request.sid then

		request:send({ headers = default_headers, status = "400 Bad Request" });

		return;

	end

	local session = sessions[request.sid];

	if error == "stream-error" then -- Remote stream error, we close normally

		session:close();

	else

		session:close({ condition = "bad-format", text = "Error processing stream" });

	end

end

local dead_sessions = {};

function on_timer()

	-- log("debug", "Checking for requests soon to timeout...");

	-- Identify requests timing out within the next few seconds

	local now = os_time() + 3;

	for request in pairs(waiting_requests) do

		if request.reply_before <= now then

			log("debug", "%s was soon to timeout, sending empty response", request.id);

			-- Send empty response to let the

			-- client know we're still here

			if request.conn then

				sessions[request.sid].send("");

			end

		end

	end

	now = now - 3;

	local n_dead_sessions = 0;

	for session, inactive_since in pairs(inactive_sessions) do

		if session.bosh_max_inactive then

			if now - inactive_since > session.bosh_max_inactive then

				(session.log or log)("debug", "BOSH client inactive too long, destroying session at %d", now);

				sessions[session.sid]  = nil;

				inactive_sessions[session] = nil;

				n_dead_sessions = n_dead_sessions + 1;

				dead_sessions[n_dead_sessions] = session;

			end

		else

			inactive_sessions[session] = nil;

		end

	end

	for i=1,n_dead_sessions do

		local session = dead_sessions[i];

		dead_sessions[i] = nil;

		sm_destroy_session(session, "BOSH client silent for over "..session.bosh_max_inactive.." seconds");

	end

	return 1;

end

local function setup()

	local ports = module:get_option("bosh_ports") or { 5280 };

	httpserver.new_from_config(ports, handle_request, { base = "http-bind" });

	timer.add_task(1, on_timer);

end

if prosody.start_time then -- already started

	setup();

else

	prosody.events.add_handler("server-started", setup);

end