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comparison mod_websocket/mod_websocket.lua @ 842:32df4d13f178

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mod_websocket: More robust frame handling
author Florian Zeitz <florob@babelmonkeys.de>
date Fri, 05 Oct 2012 16:57:34 +0200
parents f568661c9d39
children a0987c0e4e1d
comparison
equal deleted inserted replaced
841:0649883de4d3 842:32df4d13f178
45 local pos = 1; 45 local pos = 1;
46 local length_bytes = 0; 46 local length_bytes = 0;
47 local counter = 0; 47 local counter = 0;
48 local tmp_byte; 48 local tmp_byte;
49 49
50 if #frame < 2 then return; end
51
50 tmp_byte = string.byte(frame, pos); 52 tmp_byte = string.byte(frame, pos);
51 result.FIN = band(tmp_byte, 0x80) > 0; 53 result.FIN = band(tmp_byte, 0x80) > 0;
52 result.RSV1 = band(tmp_byte, 0x40) > 0; 54 result.RSV1 = band(tmp_byte, 0x40) > 0;
53 result.RSV2 = band(tmp_byte, 0x20) > 0; 55 result.RSV2 = band(tmp_byte, 0x20) > 0;
54 result.RSV3 = band(tmp_byte, 0x10) > 0; 56 result.RSV3 = band(tmp_byte, 0x10) > 0;
65 elseif result.length == 127 then 67 elseif result.length == 127 then
66 length_bytes = 8; 68 length_bytes = 8;
67 result.length = 0; 69 result.length = 0;
68 end 70 end
69 71
72 if #frame < (2 + length_bytes) then return; end
73
70 for i = 1, length_bytes do 74 for i = 1, length_bytes do
71 pos = pos + 1; 75 pos = pos + 1;
72 result.length = result.length * 256 + string.byte(frame, pos); 76 result.length = result.length * 256 + string.byte(frame, pos);
73 end 77 end
78
79 if #frame < (2 + length_bytes + (result.MASK and 4 or 0) + result.length) then return; end
74 80
75 if result.MASK then 81 if result.MASK then
76 result.key = {string.byte(frame, pos+1), string.byte(frame, pos+2), 82 result.key = {string.byte(frame, pos+1), string.byte(frame, pos+2),
77 string.byte(frame, pos+3), string.byte(frame, pos+4)} 83 string.byte(frame, pos+3), string.byte(frame, pos+4)}
78 84
84 end 90 end
85 else 91 else
86 result.data = frame:sub(pos + 1, pos + result.length); 92 result.data = frame:sub(pos + 1, pos + result.length);
87 end 93 end
88 94
89 return result; 95 return result, 2 + length_bytes + (result.MASK and 4 or 0) + result.length;
90 end 96 end
91 97
92 local function build_frame(desc) 98 local function build_frame(desc)
93 local length; 99 local length;
94 local result = ""; 100 local result = "";
101 local data = desc.data or "";
95 102
96 result = result .. string.char(0x80 * (desc.FIN and 1 or 0) + desc.opcode); 103 result = result .. string.char(0x80 * (desc.FIN and 1 or 0) + desc.opcode);
97 104
98 length = #desc.data; 105 length = #data;
99 if length <= 125 then -- 7-bit length 106 if length <= 125 then -- 7-bit length
100 result = result .. string.char(length); 107 result = result .. string.char(length);
101 elseif length <= 0xFFFF then -- 2-byte length 108 elseif length <= 0xFFFF then -- 2-byte length
102 result = result .. string.char(126); 109 result = result .. string.char(126);
103 result = result .. string.char(length/0x100) .. string.char(length%0x100); 110 result = result .. string.char(length/0x100) .. string.char(length%0x100);
106 for i = 7, 0, -1 do 113 for i = 7, 0, -1 do
107 result = result .. string.char(( length / (2^(8*i)) ) % 0x100); 114 result = result .. string.char(( length / (2^(8*i)) ) % 0x100);
108 end 115 end
109 end 116 end
110 117
111 result = result .. desc.data; 118 result = result .. data;
112 119
113 return result; 120 return result;
114 end 121 end
115 122
116 --- Stream events handlers 123 --- Stream events handlers
294 function session.reset_stream() 301 function session.reset_stream()
295 session.notopen = true; 302 session.notopen = true;
296 session.stream:reset(); 303 session.stream:reset();
297 end 304 end
298 305
306 local function websocket_close(code, message)
307 local data = string.char(code/0x100) .. string.char(code%0x100) .. message;
308 conn:write(build_frame({opcode = 0x8, FIN = true, data = data}));
309 conn:close();
310 end
311
299 local filter = session.filter; 312 local filter = session.filter;
300 local buffer = ""; 313 local dataBuffer;
301 function session.data(data) 314 local function handle_frame(frame)
302 local frame = parse_frame(data);
303
304 module:log("debug", "Websocket received: %s (%i bytes)", frame.data, #frame.data); 315 module:log("debug", "Websocket received: %s (%i bytes)", frame.data, #frame.data);
305 if frame.opcode == 0x0 or frame.opcode == 0x1 then -- Text or continuation frame 316
306 buffer = buffer .. frame.data; 317 -- Error cases
318 if frame.RSV1 or frame.RSV2 or frame.RSV3 then -- Reserved bits non zero
319 websocket_close(1002, "Reserved bits not zero");
320 return false;
321 end
322
323 if frame.opcode >= 0x8 and frame.length > 125 then -- Control frame with too much payload
324 websocket_close(1002, "Payload too large");
325 return false;
326 end
327
328 if frame.opcode >= 0x8 and not frame.FIN then -- Fragmented control frame
329 websocket_close(1002, "Fragmented control frame");
330 return false;
331 end
332
333 if (frame.opcode > 0x2 and frame.opcode < 0x8) or (frame.opcode > 0xA) then
334 websocket_close(1002, "Reserved opcode");
335 return false;
336 end
337
338 if frame.opcode == 0x0 and not dataBuffer then
339 websocket_close(1002, "Unexpected continuation frame");
340 return false;
341 end
342
343 if (frame.opcode == 0x1 or frame.opcode == 0x2) and dataBuffer then
344 websocket_close(1002, "Continuation frame expected");
345 return false;
346 end
347
348 -- Valid cases
349 if frame.opcode == 0x0 then -- Continuation frame
350 dataBuffer = dataBuffer .. frame.data;
351 elseif frame.opcode == 0x1 then -- Text frame
352 dataBuffer = frame.data;
353 elseif frame.opcode == 0x2 then -- Binary frame
354 websocket_close(1003, "Only text frames are supported");
355 return false;
356 elseif frame.opcode == 0x8 then -- Close request
357 websocket_close(1000, "Goodbye");
358 return false;
307 elseif frame.opcode == 0x9 then -- Ping frame 359 elseif frame.opcode == 0x9 then -- Ping frame
308 frame.opcode = 0xA; 360 frame.opcode = 0xA;
309 conn:write(build_frame(frame)); 361 conn:write(build_frame(frame));
310 return; 362 return true;
311 else 363 else
312 log("warn", "Received frame with unsupported opcode %i", frame.opcode); 364 log("warn", "Received frame with unsupported opcode %i", frame.opcode);
313 return; 365 return true;
314 end 366 end
315 367
316 if frame.FIN then 368 if frame.FIN then
317 data = buffer; 369 data = dataBuffer;
318 buffer = ""; 370 dataBuffer = nil;
319 371
320 -- COMPAT: Current client implementations send a self-closing <stream:stream> 372 -- COMPAT: Current client implementations send a self-closing <stream:stream>
321 if self_closing_stream then 373 if self_closing_stream then
322 data = data:gsub("(<stream:stream.*)/>$", "%1>"); 374 data = data:gsub("(<stream:stream.*)/>$", "%1>");
323 end 375 end
327 local ok, err = stream:feed(data); 379 local ok, err = stream:feed(data);
328 if ok then return; end 380 if ok then return; end
329 log("debug", "Received invalid XML (%s) %d bytes: %s", tostring(err), #data, data:sub(1, 300):gsub("[\r\n]+", " "):gsub("[%z\1-\31]", "_")); 381 log("debug", "Received invalid XML (%s) %d bytes: %s", tostring(err), #data, data:sub(1, 300):gsub("[\r\n]+", " "):gsub("[%z\1-\31]", "_"));
330 session:close("not-well-formed"); 382 session:close("not-well-formed");
331 end 383 end
384 end
385 return true;
386 end
387
388 local frameBuffer = "";
389 function session.data(data)
390 frameBuffer = frameBuffer .. data;
391 local frame, length = parse_frame(frameBuffer);
392
393 while frame do
394 frameBuffer = frameBuffer:sub(length + 1);
395 if not handle_frame(frame) then return; end
396 frame, length = parse_frame(frameBuffer);
332 end 397 end
333 end 398 end
334 399
335 function session.send(s) 400 function session.send(s)
336 conn:write(build_frame({ FIN = true, opcode = 0x01, data = tostring(s)})); 401 conn:write(build_frame({ FIN = true, opcode = 0x01, data = tostring(s)}));
379 return [[<!DOCTYPE html><html><head><title>Websocket</title></head><body> 444 return [[<!DOCTYPE html><html><head><title>Websocket</title></head><body>
380 <p>It works! Now point your WebSocket client to this URL to connect to Prosody.</p> 445 <p>It works! Now point your WebSocket client to this URL to connect to Prosody.</p>
381 </body></html>]]; 446 </body></html>]];
382 end 447 end
383 448
449 -- TODO: Handle requested subprotocols
450
384 response.conn:setlistener(listener); 451 response.conn:setlistener(listener);
385 response.status = "101 Switching Protocols"; 452 response.status = "101 Switching Protocols";
386 response.headers.Upgrade = "websocket"; 453 response.headers.Upgrade = "websocket";
387 response.headers.Connection = "Upgrade"; 454 response.headers.Connection = "Upgrade";
388 response.headers.Sec_WebSocket_Accept = base64(sha1(request.headers.sec_websocket_key .. "258EAFA5-E914-47DA-95CA-C5AB0DC85B11")); 455 response.headers.Sec_WebSocket_Accept = base64(sha1(request.headers.sec_websocket_key .. "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"));