-- 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 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 = table.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 counter = 0;
local tmp_byte;
if #frame < 2 then return; end
tmp_byte = string.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 = string.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 + string.byte(frame, pos);
end
if #frame < (2 + length_bytes + (result.MASK and 4 or 0) + result.length) then return; end
if result.MASK then
result.key = {string.byte(frame, pos+1), string.byte(frame, pos+2),
string.byte(frame, pos+3), string.byte(frame, pos+4)}
pos = pos + 5;
result.data = "";
for i = pos, pos + result.length - 1 do
result.data = result.data .. string.char(bxor(result.key[counter+1], string.byte(frame, i)));
counter = (counter + 1) % 4;
end
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 .. string.char(0x80 * (desc.FIN and 1 or 0) + desc.opcode);
length = #data;
if length <= 125 then -- 7-bit length
result = result .. string.char(length);
elseif length <= 0xFFFF then -- 2-byte length
result = result .. string.char(126);
result = result .. string.char(length/0x100) .. string.char(length%0x100);
else -- 8-byte length
result = result .. string.char(127);
for i = 7, 0, -1 do
result = result .. string.char(( length / (2^(8*i)) ) % 0x100);
end
end
result = result .. data;
return 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 = string.char(code/0x100) .. string.char(code%0x100) .. message;
conn:write(build_frame({opcode = 0x8, FIN = true, data = data}));
conn:close();
end
local dataBuffer;
local function handle_frame(frame)
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 frame.opcode >= 0x8 and frame.length > 125 then -- Control frame with too much payload
websocket_close(1002, "Payload too large");
return false;
end
if frame.opcode >= 0x8 and not frame.FIN then -- Fragmented control frame
websocket_close(1002, "Fragmented control frame");
return false;
end
if (frame.opcode > 0x2 and frame.opcode < 0x8) or (frame.opcode > 0xA) then
websocket_close(1002, "Reserved opcode");
return false;
end
if frame.opcode == 0x0 and not dataBuffer then
websocket_close(1002, "Unexpected continuation frame");
return false;
end
if (frame.opcode == 0x1 or frame.opcode == 0x2) and dataBuffer then
websocket_close(1002, "Continuation frame expected");
return false;
end
-- Valid cases
if frame.opcode == 0x0 then -- Continuation frame
dataBuffer = dataBuffer .. frame.data;
elseif frame.opcode == 0x1 then -- Text frame
dataBuffer = frame.data;
elseif frame.opcode == 0x2 then -- Binary frame
websocket_close(1003, "Only text frames are supported");
return;
elseif frame.opcode == 0x8 then -- Close request
websocket_close(1000, "Goodbye");
return;
elseif frame.opcode == 0x9 then -- Ping frame
frame.opcode = 0xA;
conn:write(build_frame(frame));
return "";
else
log("warn", "Received frame with unsupported opcode %i", frame.opcode);
return "";
end
if frame.FIN then
data = dataBuffer;
dataBuffer = nil;
return data;
end
return "";
end
conn:setlistener(c2s_listener);
c2s_listener.onconnect(conn);
local frameBuffer = "";
add_filter(sessions[conn], "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 .. result;
frame, length = parse_frame(frameBuffer);
end
return cache;
end);
add_filter(sessions[conn], "bytes/out", function(data)
return build_frame({ FIN = true, opcode = 0x01, data = tostring(data)});
end);
response.status = "101 Switching Protocols";
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