Websocket

-- Prosody IM -- Copyright (C) 2012 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 softreq = require "util.dependencies".softreq; local portmanager = require "core.portmanager"; local bit; pcall(function() bit = require"bit"; end); bit = bit or softreq"bit32" if not bit then module:log("error", "No bit module found. Either LuaJIT 2, lua-bitop or Lua 5.2 is required"); end local band = bit.band; local bxor = bit.bxor; local rshift = bit.rshift; local t_concat = table.concat; local s_byte = string.byte; local s_char= string.char; 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 module:depends("c2s") local sessions = module:shared("c2s/sessions"); local c2s_listener = portmanager.get_service("c2s").listener; -- Websocket helpers local function parse_frame(frame) local result = {}; local pos = 1; local length_bytes = 0; local tmp_byte; if #frame < 2 then return; end tmp_byte = s_byte(frame, pos); result.FIN = band(tmp_byte, 0x80) > 0; result.RSV1 = band(tmp_byte, 0x40) > 0; result.RSV2 = band(tmp_byte, 0x20) > 0; result.RSV3 = band(tmp_byte, 0x10) > 0; result.opcode = band(tmp_byte, 0x0F); pos = pos + 1; tmp_byte = s_byte(frame, pos); result.MASK = band(tmp_byte, 0x80) > 0; result.length = band(tmp_byte, 0x7F); if result.length == 126 then length_bytes = 2; result.length = 0; elseif result.length == 127 then length_bytes = 8; result.length = 0; end if #frame < (2 + length_bytes) then return; end for i = 1, length_bytes do pos = pos + 1; result.length = result.length * 256 + s_byte(frame, pos); end if #frame < (2 + length_bytes + (result.MASK and 4 or 0) + result.length) then return; end if result.MASK then local counter = 0; local data = {}; local key = {s_byte(frame, pos+1), s_byte(frame, pos+2), s_byte(frame, pos+3), s_byte(frame, pos+4)} result.key = key; pos = pos + 5; for i = pos, pos + result.length - 1 do data[#data+1] = s_char(bxor(key[counter+1], s_byte(frame, i))); counter = (counter + 1) % 4; end result.data = t_concat(data, ""); else result.data = frame:sub(pos + 1, pos + result.length); end return result, 2 + length_bytes + (result.MASK and 4 or 0) + result.length; end local function build_frame(desc) local length; local result = {}; local data = desc.data or ""; result[#result+1] = s_char(0x80 * (desc.FIN and 1 or 0) + desc.opcode); length = #data; if length <= 125 then -- 7-bit length result[#result+1] = s_char(length); elseif length <= 0xFFFF then -- 2-byte length result[#result+1] = s_char(126); result[#result+1] = s_char(rshift(length, 8)) .. s_char(length%0x100); else -- 8-byte length result[#result+1] = s_char(127); local length_bytes = {}; for i = 8, 1, -1 do length_bytes[i] = s_char(length % 0x100); length = rshift(length, 8); end result[#result+1] = t_concat(length_bytes, ""); end result[#result+1] = data; return t_concat(result, ""); end --- Filter stuff 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 [[Websocket

It works! Now point your WebSocket client to this URL to connect to Prosody.

]]; 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) local data = s_char(rshift(code, 8)) .. s_char(code%0x100) .. message; conn:write(build_frame({opcode = 0x8, FIN = true, data = data})); conn:close(); end local dataBuffer; local function handle_frame(frame) local opcode = frame.opcode; local length = frame.length; module:log("debug", "Websocket received: %s (%i bytes)", frame.data, #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 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 = s_byte(frame.data, 1) * 256 + s_byte(frame.data, 2) 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 ""; 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._http_request_headers = request.headers; session.secure = consider_websocket_secure or session.secure; 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] = result; frame, length = parse_frame(frameBuffer); end return t_concat(cache, ""); 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; }; }); module:add_item("alt-conn-method", { rel = "urn:xmpp:altconnect:websocket"; href = module:http_url(nil, "xmpp-websocket"):gsub("^http", "ws"); }); end