aboutsummaryrefslogtreecommitdiffstats
path: root/net/websocket.lua
blob: bb26c1002d101061d796594acad304a3380f407c (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
-- Prosody IM
-- Copyright (C) 2012 Florian Zeitz
-- Copyright (C) 2014 Daurnimator
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--

local t_concat = table.concat;

local http = require "net.http";
local frames = require "net.websocket.frames";
local base64 = require "util.encodings".base64;
local sha1 = require "util.hashes".sha1;
local random_bytes = require "util.random".bytes;
local timer = require "util.timer";
local log = require "util.logger".init "websocket";

local close_timeout = 3; -- Seconds to wait after sending close frame until closing connection.

local websockets = {};

local websocket_listeners = {};
function websocket_listeners.ondisconnect(conn, err)
	local s = websockets[conn];
	websockets[conn] = nil;
	if s.close_timer then
		timer.stop(s.close_timer);
		s.close_timer = nil;
	end
	s.readyState = 3;
	if s.close_code == nil and s.onerror then s:onerror(err); end
	if s.onclose then s:onclose(s.close_code, s.close_message or err); end
end

function websocket_listeners.ondetach(conn)
	websockets[conn] = nil;
end

local function fail(s, code, reason)
	log("warn", "WebSocket connection failed, closing. %d %s", code, reason);
	s:close(code, reason);
	s.conn:close();
	return false
end

function websocket_listeners.onincoming(conn, buffer, err) -- luacheck: ignore 212/err
	local s = websockets[conn];
	s.readbuffer = s.readbuffer..buffer;
	while true do
		local frame, len = frames.parse(s.readbuffer);
		if frame == nil then break end
		s.readbuffer = s.readbuffer:sub(len+1);

		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
			return fail(s, 1002, "Reserved bits not zero");
		end

		if frame.opcode < 0x8 then
			local databuffer = s.databuffer;
			if frame.opcode == 0x0 then -- Continuation frames
				if not databuffer then
					return fail(s, 1002, "Unexpected continuation frame");
				end
				databuffer[#databuffer+1] = frame.data;
			elseif frame.opcode == 0x1 or frame.opcode == 0x2 then -- Text or Binary frame
				if databuffer then
					return fail(s, 1002, "Continuation frame expected");
				end
				databuffer = {type=frame.opcode, frame.data};
				s.databuffer = databuffer;
			else
				return fail(s, 1002, "Reserved opcode");
			end
			if frame.FIN then
				s.databuffer = nil;
				if s.onmessage then
					s:onmessage(t_concat(databuffer), databuffer.type);
				end
			end
		else -- Control frame
			if frame.length > 125 then -- Control frame with too much payload
				return fail(s, 1002, "Payload too large");
			elseif not frame.FIN then -- Fragmented control frame
				return fail(s, 1002, "Fragmented control frame");
			end
			if frame.opcode == 0x8 then -- Close request
				if frame.length == 1 then
					return fail(s, 1002, "Close frame with payload, but too short for status code");
				end
				local status_code, message = frames.parse_close(frame.data);
				if status_code == nil then
					--[[ RFC 6455 7.4.1
					1005 is a reserved value and MUST NOT be set as a status code in a
					Close control frame by an endpoint.  It is designated for use in
					applications expecting a status code to indicate that no status
					code was actually present.
					]]
					status_code = 1005
				elseif status_code < 1000 then
					return fail(s, 1002, "Closed with invalid status code");
				elseif ((status_code > 1003 and status_code < 1007) or status_code > 1011) and status_code < 3000 then
					return fail(s, 1002, "Closed with reserved status code");
				end
				s.close_code, s.close_message = status_code, message;
				s:close(1000);
				return true;
			elseif frame.opcode == 0x9 then -- Ping frame
				frame.opcode = 0xA;
				frame.MASK = true; -- RFC 6455 6.1.5: If the data is being sent by the client, the frame(s) MUST be masked
				conn:write(frames.build(frame));
			elseif frame.opcode == 0xA then -- Pong frame
				log("debug", "Received unexpected pong frame: " .. tostring(frame.data));
			else
				return fail(s, 1002, "Reserved opcode");
			end
		end
	end
	return true;
end

local websocket_methods = {};
local function close_timeout_cb(now, timerid, s) -- luacheck: ignore 212/now 212/timerid
	s.close_timer = nil;
	log("warn", "Close timeout waiting for server to close, closing manually.");
	s.conn:close();
end
function websocket_methods:close(code, reason)
	if self.readyState < 2 then
		code = code or 1000;
		log("debug", "closing WebSocket with code %i: %s" , code , reason);
		self.readyState = 2;
		local conn = self.conn;
		conn:write(frames.build_close(code, reason, true));
		-- Do not close socket straight away, wait for acknowledgement from server.
		self.close_timer = timer.add_task(close_timeout, close_timeout_cb, self);
	elseif self.readyState == 2 then
		log("debug", "tried to close a closing WebSocket, closing the raw socket.");
		-- Stop timer
		if self.close_timer then
			timer.stop(self.close_timer);
			self.close_timer = nil;
		end
		local conn = self.conn;
		conn:close();
	else
		log("debug", "tried to close a closed WebSocket, ignoring.");
	end
end
function websocket_methods:send(data, opcode)
	if self.readyState < 1 then
		return nil, "WebSocket not open yet, unable to send data.";
	elseif self.readyState >= 2 then
		return nil, "WebSocket closed, unable to send data.";
	end
	if opcode == "text" or opcode == nil then
		opcode = 0x1;
	elseif opcode == "binary" then
		opcode = 0x2;
	end
	local frame = {
		FIN = true;
		MASK = true; -- RFC 6455 6.1.5: If the data is being sent by the client, the frame(s) MUST be masked
		opcode = opcode;
		data = tostring(data);
	};
	log("debug", "WebSocket sending frame: opcode=%0x, %i bytes", frame.opcode, #frame.data);
	return self.conn:write(frames.build(frame));
end

local websocket_metatable = {
	__index = websocket_methods;
};

local function connect(url, ex, listeners)
	ex = ex or {};

	--[[RFC 6455 4.1.7:
		The request MUST include a header field with the name
	|Sec-WebSocket-Key|.  The value of this header field MUST be a
	nonce consisting of a randomly selected 16-byte value that has
	been base64-encoded (see Section 4 of [RFC4648]).  The nonce
	MUST be selected randomly for each connection.
	]]
	local key = base64.encode(random_bytes(16));

	-- Either a single protocol string or an array of protocol strings.
	local protocol = ex.protocol;
	if type(protocol) == "string" then
		protocol = { protocol, [protocol] = true };
	elseif type(protocol) == "table" and protocol[1] then
		for _, v in ipairs(protocol) do
			protocol[v] = true;
		end
	else
		protocol = nil;
	end

	local headers = {
		["Upgrade"] = "websocket";
		["Connection"] = "Upgrade";
		["Sec-WebSocket-Key"] = key;
		["Sec-WebSocket-Protocol"] = protocol and t_concat(protocol, ", ");
		["Sec-WebSocket-Version"] = "13";
		["Sec-WebSocket-Extensions"] = ex.extensions;
	}
	if ex.headers then
		for k,v in pairs(ex.headers) do
			headers[k] = v;
		end
	end

	local s = setmetatable({
		readbuffer = "";
		databuffer = nil;
		conn = nil;
		close_code = nil;
		close_message = nil;
		close_timer = nil;
		readyState = 0;
		protocol = nil;

		url = url;

		onopen = listeners.onopen;
		onclose = listeners.onclose;
		onmessage = listeners.onmessage;
		onerror = listeners.onerror;
	}, websocket_metatable);

	local http_url = url:gsub("^(ws)", "http");
	local http_req = http.request(http_url, { -- luacheck: ignore 211/http_req
		method = "GET";
		headers = headers;
		sslctx = ex.sslctx;
		insecure = ex.insecure;
	}, function(b, c, r, http_req)
		if c ~= 101
		   or r.headers["connection"]:lower() ~= "upgrade"
		   or r.headers["upgrade"] ~= "websocket"
		   or r.headers["sec-websocket-accept"] ~= base64.encode(sha1(key .. "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"))
		   or (protocol and not protocol[r.headers["sec-websocket-protocol"]])
		   then
			s.readyState = 3;
			log("warn", "WebSocket connection to %s failed: %s", url, b);
			if s.onerror then s:onerror("connecting-failed"); end
			return;
		end

		s.protocol = r.headers["sec-websocket-protocol"];

		-- Take possession of socket from http
		local conn = http_req.conn;
		http_req.conn = nil;
		s.conn = conn;
		websockets[conn] = s;
		conn:setlistener(websocket_listeners);

		log("debug", "WebSocket connected successfully to %s", url);
		s.readyState = 1;
		if s.onopen then s:onopen(); end
		websocket_listeners.onincoming(conn, b);
	end);

	return s;
end

return {
	connect = connect;
};