aboutsummaryrefslogtreecommitdiffstats
path: root/plugins/mod_websocket.lua
blob: 313dbd4193cf74d81d6b4b74908fd448fd13e97e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
-- Prosody IM
-- Copyright (C) 2012-2014 Florian Zeitz
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--

module:set_global();

local add_filter = require "util.filters".add_filter;
local sha1 = require "util.hashes".sha1;
local base64 = require "util.encodings".base64.encode;
local st = require "util.stanza";
local parse_xml = require "util.xml".parse;
local portmanager = require "core.portmanager";
local sm_destroy_session = sessionmanager.destroy_session;
local log = module._log;

local websocket_frames = require"net.websocket.frames";
local parse_frame = websocket_frames.parse;
local build_frame = websocket_frames.build;
local build_close = websocket_frames.build_close;
local parse_close = websocket_frames.parse_close;

local t_concat = table.concat;

local consider_websocket_secure = module:get_option_boolean("consider_websocket_secure");
local cross_domain = module:get_option("cross_domain_websocket");
if cross_domain then
	if cross_domain == true then
		cross_domain = "*";
	elseif type(cross_domain) == "table" then
		cross_domain = t_concat(cross_domain, ", ");
	end
	if type(cross_domain) ~= "string" then
		cross_domain = nil;
	end
end

local xmlns_framing = "urn:ietf:params:xml:ns:xmpp-framing";
local xmlns_streams = "http://etherx.jabber.org/streams";
local xmlns_client = "jabber:client";
local stream_xmlns_attr = {xmlns='urn:ietf:params:xml:ns:xmpp-streams'};

module:depends("c2s")
local sessions = module:shared("c2s/sessions");
local c2s_listener = portmanager.get_service("c2s").listener;

--- Session methods
local function session_open_stream(session)
	local attr = {
		xmlns = xmlns_framing,
		version = "1.0",
		id = session.streamid or "",
		from = session.host
	};
	session.send(st.stanza("open", attr));
end

local function session_close(session, reason)
	local log = session.log or log;
	if session.conn then
		if session.notopen then
			session:open_stream();
		end
		if reason then -- nil == no err, initiated by us, false == initiated by client
			local stream_error = st.stanza("stream:error");
			if type(reason) == "string" then -- assume stream error
				stream_error:tag(reason, {xmlns = 'urn:ietf:params:xml:ns:xmpp-streams' });
			elseif type(reason) == "table" then
				if reason.condition then
					stream_error:tag(reason.condition, stream_xmlns_attr):up();
					if reason.text then
						stream_error:tag("text", stream_xmlns_attr):text(reason.text):up();
					end
					if reason.extra then
						stream_error:add_child(reason.extra);
					end
				elseif reason.name then -- a stanza
					stream_error = reason;
				end
			end
			log("debug", "Disconnecting client, <stream:error> is: %s", tostring(stream_error));
			session.send(stream_error);
		end

		session.send(st.stanza("close", { xmlns = xmlns_framing }));
		function session.send() return false; end

		local reason = (reason and (reason.name or reason.text or reason.condition)) or reason;
		session.log("debug", "c2s stream for %s closed: %s", session.full_jid or ("<"..session.ip..">"), reason or "session closed");

		-- Authenticated incoming stream may still be sending us stanzas, so wait for </stream:stream> from remote
		local conn = session.conn;
		if reason == nil and not session.notopen and session.type == "c2s" then
			-- Grace time to process data from authenticated cleanly-closed stream
			add_task(stream_close_timeout, function ()
				if not session.destroyed then
					session.log("warn", "Failed to receive a stream close response, closing connection anyway...");
					sm_destroy_session(session, reason);
					conn:write(build_close(1000, "Stream closed"));
					conn:close();
				end
			end);
		else
			sm_destroy_session(session, reason);
			conn:write(build_close(1000, "Stream closed"));
			conn:close();
		end
	end
end


--- Filters
local function filter_open_close(data)
	if not data:find(xmlns_framing, 1, true) then return data; end

	local oc = parse_xml(data);
	if not oc then return data; end
	if oc.attr.xmlns ~= xmlns_framing then return data; end
	if oc.name == "close" then return "</stream:stream>"; end
	if oc.name == "open" then
		oc.name = "stream:stream";
		oc.attr.xmlns = nil;
		oc.attr["xmlns:stream"] = xmlns_streams;
		return oc:top_tag();
	end

	return data;
end
function handle_request(event, path)
	local request, response = event.request, event.response;
	local conn = response.conn;

	if not request.headers.sec_websocket_key then
		response.headers.content_type = "text/html";
		return [[<!DOCTYPE html><html><head><title>Websocket</title></head><body>
			<p>It works! Now point your WebSocket client to this URL to connect to Prosody.</p>
			</body></html>]];
	end

	local wants_xmpp = false;
	(request.headers.sec_websocket_protocol or ""):gsub("([^,]*),?", function (proto)
		if proto == "xmpp" then wants_xmpp = true; end
	end);

	if not wants_xmpp then
		return 501;
	end

	local function websocket_close(code, message)
		conn:write(build_close(code, message));
		conn:close();
	end

	local dataBuffer;
	local function handle_frame(frame)
		local opcode = frame.opcode;
		local length = frame.length;
		module:log("debug", "Websocket received frame: opcode=%0x, %i bytes", frame.opcode, #frame.data);

		-- Error cases
		if frame.RSV1 or frame.RSV2 or frame.RSV3 then -- Reserved bits non zero
			websocket_close(1002, "Reserved bits not zero");
			return false;
		end

		if opcode == 0x8 then -- close frame
			if length == 1 then
				websocket_close(1002, "Close frame with payload, but too short for status code");
				return false;
			elseif length >= 2 then
				local status_code = parse_close(frame.data)
				if status_code < 1000 then
					websocket_close(1002, "Closed with invalid status code");
					return false;
				elseif ((status_code > 1003 and status_code < 1007) or status_code > 1011) and status_code < 3000 then
					websocket_close(1002, "Closed with reserved status code");
					return false;
				end
			end
		end

		if opcode >= 0x8 then
			if length > 125 then -- Control frame with too much payload
				websocket_close(1002, "Payload too large");
				return false;
			end

			if not frame.FIN then -- Fragmented control frame
				websocket_close(1002, "Fragmented control frame");
				return false;
			end
		end

		if (opcode > 0x2 and opcode < 0x8) or (opcode > 0xA) then
			websocket_close(1002, "Reserved opcode");
			return false;
		end

		if opcode == 0x0 and not dataBuffer then
			websocket_close(1002, "Unexpected continuation frame");
			return false;
		end

		if (opcode == 0x1 or opcode == 0x2) and dataBuffer then
			websocket_close(1002, "Continuation frame expected");
			return false;
		end

		-- Valid cases
		if opcode == 0x0 then -- Continuation frame
			dataBuffer[#dataBuffer+1] = frame.data;
		elseif opcode == 0x1 then -- Text frame
			dataBuffer = {frame.data};
		elseif opcode == 0x2 then -- Binary frame
			websocket_close(1003, "Only text frames are supported");
			return;
		elseif opcode == 0x8 then -- Close request
			websocket_close(1000, "Goodbye");
			return;
		elseif opcode == 0x9 then -- Ping frame
			frame.opcode = 0xA;
			conn:write(build_frame(frame));
			return "";
		elseif opcode == 0xA then -- Pong frame
			module:log("warn", "Received unexpected pong frame: " .. tostring(frame.data));
			return "";
		else
			log("warn", "Received frame with unsupported opcode %i", opcode);
			return "";
		end

		if frame.FIN then
			local data = t_concat(dataBuffer, "");
			dataBuffer = nil;
			return data;
		end
		return "";
	end

	conn:setlistener(c2s_listener);
	c2s_listener.onconnect(conn);

	local session = sessions[conn];

	session.secure = consider_websocket_secure or session.secure;

	session.open_stream = session_open_stream;
	session.close = session_close;

	local frameBuffer = "";
	add_filter(session, "bytes/in", function(data)
		local cache = {};
		frameBuffer = frameBuffer .. data;
		local frame, length = parse_frame(frameBuffer);

		while frame do
			frameBuffer = frameBuffer:sub(length + 1);
			local result = handle_frame(frame);
			if not result then return; end
			cache[#cache+1] = filter_open_close(result);
			frame, length = parse_frame(frameBuffer);
		end
		return t_concat(cache, "");
	end);

	add_filter(session, "stanzas/out", function(stanza)
		local attr = stanza.attr;
		attr.xmlns = attr.xmlns or xmlns_client;
		if stanza.name:find("^stream:") then
			attr["xmlns:stream"] = attr["xmlns:stream"] or xmlns_streams;
		end
		return stanza;
	end);

	add_filter(session, "bytes/out", function(data)
		return build_frame({ FIN = true, opcode = 0x01, data = tostring(data)});
	end);

	response.status_code = 101;
	response.headers.upgrade = "websocket";
	response.headers.connection = "Upgrade";
	response.headers.sec_webSocket_accept = base64(sha1(request.headers.sec_websocket_key .. "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"));
	response.headers.sec_webSocket_protocol = "xmpp";
	response.headers.access_control_allow_origin = cross_domain;

	return "";
end

function module.add_host(module)
	module:depends("http");
	module:provides("http", {
		name = "websocket";
		default_path = "xmpp-websocket";
		route = {
			["GET"] = handle_request;
			["GET /"] = handle_request;
		};
	});
end