plugins/mod_websocket.lua

   1 -- Prosody IM
   2 -- Copyright (C) 2012-2014 Florian Zeitz
   3 --
   4 -- This project is MIT/X11 licensed. Please see the
   5 -- COPYING file in the source package for more information.
   6 --
   7 -- luacheck: ignore 431/log
   8
   9 module:set_global();
  10
  11 local add_task = require "util.timer".add_task;
  12 local add_filter = require "util.filters".add_filter;
  13 local sha1 = require "util.hashes".sha1;
  14 local base64 = require "util.encodings".base64.encode;
  15 local st = require "util.stanza";
  16 local parse_xml = require "util.xml".parse;
  17 local portmanager = require "core.portmanager";
  18 local sm_destroy_session = require"core.sessionmanager".destroy_session;
  19 local log = module._log;
  20
  21 local websocket_frames = require"net.websocket.frames";
  22 local parse_frame = websocket_frames.parse;
  23 local build_frame = websocket_frames.build;
  24 local build_close = websocket_frames.build_close;
  25 local parse_close = websocket_frames.parse_close;
  26
  27 local t_concat = table.concat;
  28
  29 local stream_close_timeout = module:get_option_number("c2s_close_timeout", 5);
  30 local consider_websocket_secure = module:get_option_boolean("consider_websocket_secure");
  31 local cross_domain = module:get_option("cross_domain_websocket");
  32 if cross_domain then
  33         if cross_domain == true then
  34                 cross_domain = "*";
  35         elseif type(cross_domain) == "table" then
  36                 cross_domain = t_concat(cross_domain, ", ");
  37         end
  38         if type(cross_domain) ~= "string" then
  39                 cross_domain = nil;
  40         end
  41 end
  42
  43 local xmlns_framing = "urn:ietf:params:xml:ns:xmpp-framing";
  44 local xmlns_streams = "http://etherx.jabber.org/streams";
  45 local xmlns_client = "jabber:client";
  46 local stream_xmlns_attr = {xmlns='urn:ietf:params:xml:ns:xmpp-streams'};
  47
  48 module:depends("c2s")
  49 local sessions = module:shared("c2s/sessions");
  50 local c2s_listener = portmanager.get_service("c2s").listener;
  51
  52 --- Session methods
  53 local function session_open_stream(session)
  54         local attr = {
  55                 xmlns = xmlns_framing,
  56                 version = "1.0",
  57                 id = session.streamid or "",
  58                 from = session.host
  59         };
  60         session.send(st.stanza("open", attr));
  61 end
  62
  63 local function session_close(session, reason)
  64         local log = session.log or log;
  65         if session.conn then
  66                 if session.notopen then
  67                         session:open_stream();
  68                 end
  69                 if reason then -- nil == no err, initiated by us, false == initiated by client
  70                         local stream_error = st.stanza("stream:error");
  71                         if type(reason) == "string" then -- assume stream error
  72                                 stream_error:tag(reason, {xmlns = 'urn:ietf:params:xml:ns:xmpp-streams' });
  73                         elseif type(reason) == "table" then
  74                                 if reason.condition then
  75                                         stream_error:tag(reason.condition, stream_xmlns_attr):up();
  76                                         if reason.text then
  77                                                 stream_error:tag("text", stream_xmlns_attr):text(reason.text):up();
  78                                         end
  79                                         if reason.extra then
  80                                                 stream_error:add_child(reason.extra);
  81                                         end
  82                                 elseif reason.name then -- a stanza
  83                                         stream_error = reason;
  84                                 end
  85                         end
  86                         log("debug", "Disconnecting client, <stream:error> is: %s", tostring(stream_error));
  87                         session.send(stream_error);
  88                 end
  89
  90                 session.send(st.stanza("close", { xmlns = xmlns_framing }));
  91                 function session.send() return false; end
  92
  93                 local reason = (reason and (reason.name or reason.text or reason.condition)) or reason;
  94                 session.log("debug", "c2s stream for %s closed: %s", session.full_jid or ("<"..session.ip..">"), reason or "session closed");
  95
  96                 -- Authenticated incoming stream may still be sending us stanzas, so wait for </stream:stream> from remote
  97                 local conn = session.conn;
  98                 if reason == nil and not session.notopen and session.type == "c2s" then
  99                         -- Grace time to process data from authenticated cleanly-closed stream
 100                         add_task(stream_close_timeout, function ()
 101                                 if not session.destroyed then
 102                                         session.log("warn", "Failed to receive a stream close response, closing connection anyway...");
 103                                         sm_destroy_session(session, reason);
 104                                         conn:write(build_close(1000, "Stream closed"));
 105                                         conn:close();
 106                                 end
 107                         end);
 108                 else
 109                         sm_destroy_session(session, reason);
 110                         conn:write(build_close(1000, "Stream closed"));
 111                         conn:close();
 112                 end
 113         end
 114 end
 115
 116
 117 --- Filters
 118 local function filter_open_close(data)
 119         if not data:find(xmlns_framing, 1, true) then return data; end
 120
 121         local oc = parse_xml(data);
 122         if not oc then return data; end
 123         if oc.attr.xmlns ~= xmlns_framing then return data; end
 124         if oc.name == "close" then return "</stream:stream>"; end
 125         if oc.name == "open" then
 126                 oc.name = "stream:stream";
 127                 oc.attr.xmlns = nil;
 128                 oc.attr["xmlns:stream"] = xmlns_streams;
 129                 return oc:top_tag();
 130         end
 131
 132         return data;
 133 end
 134 function handle_request(event)
 135         local request, response = event.request, event.response;
 136         local conn = response.conn;
 137
 138         if not request.headers.sec_websocket_key then
 139                 response.headers.content_type = "text/html";
 140                 return [[<!DOCTYPE html><html><head><title>Websocket</title></head><body>
 141                         <p>It works! Now point your WebSocket client to this URL to connect to Prosody.</p>
 142                         </body></html>]];
 143         end
 144
 145         local wants_xmpp = false;
 146         (request.headers.sec_websocket_protocol or ""):gsub("([^,]*),?", function (proto)
 147                 if proto == "xmpp" then wants_xmpp = true; end
 148         end);
 149
 150         if not wants_xmpp then
 151                 return 501;
 152         end
 153
 154         local function websocket_close(code, message)
 155                 conn:write(build_close(code, message));
 156                 conn:close();
 157         end
 158
 159         local dataBuffer;
 160         local function handle_frame(frame)
 161                 local opcode = frame.opcode;
 162                 local length = frame.length;
 163                 module:log("debug", "Websocket received frame: opcode=%0x, %i bytes", frame.opcode, #frame.data);
 164
 165                 -- Error cases
 166                 if frame.RSV1 or frame.RSV2 or frame.RSV3 then -- Reserved bits non zero
 167                         websocket_close(1002, "Reserved bits not zero");
 168                         return false;
 169                 end
 170
 171                 if opcode == 0x8 then -- close frame
 172                         if length == 1 then
 173                                 websocket_close(1002, "Close frame with payload, but too short for status code");
 174                                 return false;
 175                         elseif length >= 2 then
 176                                 local status_code = parse_close(frame.data)
 177                                 if status_code < 1000 then
 178                                         websocket_close(1002, "Closed with invalid status code");
 179                                         return false;
 180                                 elseif ((status_code > 1003 and status_code < 1007) or status_code > 1011) and status_code < 3000 then
 181                                         websocket_close(1002, "Closed with reserved status code");
 182                                         return false;
 183                                 end
 184                         end
 185                 end
 186
 187                 if opcode >= 0x8 then
 188                         if length > 125 then -- Control frame with too much payload
 189                                 websocket_close(1002, "Payload too large");
 190                                 return false;
 191                         end
 192
 193                         if not frame.FIN then -- Fragmented control frame
 194                                 websocket_close(1002, "Fragmented control frame");
 195                                 return false;
 196                         end
 197                 end
 198
 199                 if (opcode > 0x2 and opcode < 0x8) or (opcode > 0xA) then
 200                         websocket_close(1002, "Reserved opcode");
 201                         return false;
 202                 end
 203
 204                 if opcode == 0x0 and not dataBuffer then
 205                         websocket_close(1002, "Unexpected continuation frame");
 206                         return false;
 207                 end
 208
 209                 if (opcode == 0x1 or opcode == 0x2) and dataBuffer then
 210                         websocket_close(1002, "Continuation frame expected");
 211                         return false;
 212                 end
 213
 214                 -- Valid cases
 215                 if opcode == 0x0 then -- Continuation frame
 216                         dataBuffer[#dataBuffer+1] = frame.data;
 217                 elseif opcode == 0x1 then -- Text frame
 218                         dataBuffer = {frame.data};
 219                 elseif opcode == 0x2 then -- Binary frame
 220                         websocket_close(1003, "Only text frames are supported");
 221                         return;
 222                 elseif opcode == 0x8 then -- Close request
 223                         websocket_close(1000, "Goodbye");
 224                         return;
 225                 elseif opcode == 0x9 then -- Ping frame
 226                         frame.opcode = 0xA;
 227                         conn:write(build_frame(frame));
 228                         return "";
 229                 elseif opcode == 0xA then -- Pong frame, MAY be sent unsolicited, eg as keepalive
 230                         return "";
 231                 else
 232                         log("warn", "Received frame with unsupported opcode %i", opcode);
 233                         return "";
 234                 end
 235
 236                 if frame.FIN then
 237                         local data = t_concat(dataBuffer, "");
 238                         dataBuffer = nil;
 239                         return data;
 240                 end
 241                 return "";
 242         end
 243
 244         conn:setlistener(c2s_listener);
 245         c2s_listener.onconnect(conn);
 246
 247         local session = sessions[conn];
 248
 249         session.secure = consider_websocket_secure or session.secure;
 250
 251         session.open_stream = session_open_stream;
 252         session.close = session_close;
 253
 254         local frameBuffer = "";
 255         add_filter(session, "bytes/in", function(data)
 256                 local cache = {};
 257                 frameBuffer = frameBuffer .. data;
 258                 local frame, length = parse_frame(frameBuffer);
 259
 260                 while frame do
 261                         frameBuffer = frameBuffer:sub(length + 1);
 262                         local result = handle_frame(frame);
 263                         if not result then return; end
 264                         cache[#cache+1] = filter_open_close(result);
 265                         frame, length = parse_frame(frameBuffer);
 266                 end
 267                 return t_concat(cache, "");
 268         end);
 269
 270         add_filter(session, "stanzas/out", function(stanza)
 271                 local attr = stanza.attr;
 272                 attr.xmlns = attr.xmlns or xmlns_client;
 273                 if stanza.name:find("^stream:") then
 274                         attr["xmlns:stream"] = attr["xmlns:stream"] or xmlns_streams;
 275                 end
 276                 return stanza;
 277         end, -1000);
 278
 279         add_filter(session, "bytes/out", function(data)
 280                 return build_frame({ FIN = true, opcode = 0x01, data = tostring(data)});
 281         end);
 282
 283         response.status_code = 101;
 284         response.headers.upgrade = "websocket";
 285         response.headers.connection = "Upgrade";
 286         response.headers.sec_webSocket_accept = base64(sha1(request.headers.sec_websocket_key .. "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"));
 287         response.headers.sec_webSocket_protocol = "xmpp";
 288         response.headers.access_control_allow_origin = cross_domain;
 289
 290         return "";
 291 end
 292
 293 local function keepalive(event)
 294         local session = event.session;
 295         if session.open_stream == session_open_stream then
 296                 return session.conn:write(build_frame({ opcode = 0x9, }));
 297         end
 298 end
 299
 300 module:hook("c2s-read-timeout", keepalive, -0.9);
 301
 302 function module.add_host(module)
 303         module:depends("http");
 304         module:provides("http", {
 305                 name = "websocket";
 306                 default_path = "xmpp-websocket";
 307                 route = {
 308                         ["GET"] = handle_request;
 309                         ["GET /"] = handle_request;
 310                 };
 311         });
 312         module:hook("c2s-read-timeout", keepalive, -0.9);
 313 end