plugins/mod_s2s/mod_s2s.lua

   1 -- Prosody IM
   2 -- Copyright (C) 2008-2010 Matthew Wild
   3 -- Copyright (C) 2008-2010 Waqas Hussain
   4 --
   5 -- This project is MIT/X11 licensed. Please see the
   6 -- COPYING file in the source package for more information.
   7 --
   8
   9 module:set_global();
  10
  11 local prosody = prosody;
  12 local hosts = prosody.hosts;
  13 local core_process_stanza = prosody.core_process_stanza;
  14
  15 local tostring, type = tostring, type;
  16 local t_insert = table.insert;
  17 local xpcall, traceback = xpcall, debug.traceback;
  18
  19 local add_task = require "util.timer".add_task;
  20 local st = require "util.stanza";
  21 local initialize_filters = require "util.filters".initialize;
  22 local nameprep = require "util.encodings".stringprep.nameprep;
  23 local new_xmpp_stream = require "util.xmppstream".new;
  24 local s2s_new_incoming = require "core.s2smanager".new_incoming;
  25 local s2s_new_outgoing = require "core.s2smanager".new_outgoing;
  26 local s2s_destroy_session = require "core.s2smanager".destroy_session;
  27 local uuid_gen = require "util.uuid".generate;
  28 local fire_global_event = prosody.events.fire_event;
  29
  30 local s2sout = module:require("s2sout");
  31
  32 local connect_timeout = module:get_option_number("s2s_timeout", 90);
  33 local stream_close_timeout = module:get_option_number("s2s_close_timeout", 5);
  34 local opt_keepalives = module:get_option_boolean("s2s_tcp_keepalives", module:get_option_boolean("tcp_keepalives", true));
  35 local secure_auth = module:get_option_boolean("s2s_secure_auth", false); -- One day...
  36 local secure_domains, insecure_domains =
  37         module:get_option_set("s2s_secure_domains", {})._items, module:get_option_set("s2s_insecure_domains", {})._items;
  38 local require_encryption = module:get_option_boolean("s2s_require_encryption", false);
  39
  40 local measure_connections = module:measure("connections", "counter");
  41
  42 local sessions = module:shared("sessions");
  43
  44 local log = module._log;
  45
  46 --- Handle stanzas to remote domains
  47
  48 local bouncy_stanzas = { message = true, presence = true, iq = true };
  49 local function bounce_sendq(session, reason)
  50         local sendq = session.sendq;
  51         if not sendq then return; end
  52         session.log("info", "Sending error replies for "..#sendq.." queued stanzas because of failed outgoing connection to "..tostring(session.to_host));
  53         local dummy = {
  54                 type = "s2sin";
  55                 send = function(s)
  56                         (session.log or log)("error", "Replying to to an s2s error reply, please report this! Traceback: %s", traceback());
  57                 end;
  58                 dummy = true;
  59         };
  60         for i, data in ipairs(sendq) do
  61                 local reply = data[2];
  62                 if reply and not(reply.attr.xmlns) and bouncy_stanzas[reply.name] then
  63                         reply.attr.type = "error";
  64                         reply:tag("error", {type = "cancel"})
  65                                 :tag("remote-server-not-found", {xmlns = "urn:ietf:params:xml:ns:xmpp-stanzas"}):up();
  66                         if reason then
  67                                 reply:tag("text", {xmlns = "urn:ietf:params:xml:ns:xmpp-stanzas"})
  68                                         :text("Server-to-server connection failed: "..reason):up();
  69                         end
  70                         core_process_stanza(dummy, reply);
  71                 end
  72                 sendq[i] = nil;
  73         end
  74         session.sendq = nil;
  75 end
  76
  77 -- Handles stanzas to existing s2s sessions
  78 function route_to_existing_session(event)
  79         local from_host, to_host, stanza = event.from_host, event.to_host, event.stanza;
  80         if not hosts[from_host] then
  81                 log("warn", "Attempt to send stanza from %s - a host we don't serve", from_host);
  82                 return false;
  83         end
  84         if hosts[to_host] then
  85                 log("warn", "Attempt to route stanza to a remote %s - a host we do serve?!", from_host);
  86                 return false;
  87         end
  88         local host = hosts[from_host].s2sout[to_host];
  89         if host then
  90                 -- We have a connection to this host already
  91                 if host.type == "s2sout_unauthed" and (stanza.name ~= "db:verify" or not host.dialback_key) then
  92                         (host.log or log)("debug", "trying to send over unauthed s2sout to "..to_host);
  93
  94                         -- Queue stanza until we are able to send it
  95                         if host.sendq then t_insert(host.sendq, {tostring(stanza), stanza.attr.type ~= "error" and stanza.attr.type ~= "result" and st.reply(stanza)});
  96                         else host.sendq = { {tostring(stanza), stanza.attr.type ~= "error" and stanza.attr.type ~= "result" and st.reply(stanza)} }; end
  97                         host.log("debug", "stanza [%s] queued ", stanza.name);
  98                         return true;
  99                 elseif host.type == "local" or host.type == "component" then
 100                         log("error", "Trying to send a stanza to ourselves??")
 101                         log("error", "Traceback: %s", traceback());
 102                         log("error", "Stanza: %s", tostring(stanza));
 103                         return false;
 104                 else
 105                         (host.log or log)("debug", "going to send stanza to "..to_host.." from "..from_host);
 106                         -- FIXME
 107                         if host.from_host ~= from_host then
 108                                 log("error", "WARNING! This might, possibly, be a bug, but it might not...");
 109                                 log("error", "We are going to send from %s instead of %s", tostring(host.from_host), tostring(from_host));
 110                         end
 111                         if host.sends2s(stanza) then
 112                                 host.log("debug", "stanza sent over %s", host.type);
 113                                 return true;
 114                         end
 115                 end
 116         end
 117 end
 118
 119 -- Create a new outgoing session for a stanza
 120 function route_to_new_session(event)
 121         local from_host, to_host, stanza = event.from_host, event.to_host, event.stanza;
 122         log("debug", "opening a new outgoing connection for this stanza");
 123         local host_session = s2s_new_outgoing(from_host, to_host);
 124
 125         -- Store in buffer
 126         host_session.bounce_sendq = bounce_sendq;
 127         host_session.sendq = { {tostring(stanza), stanza.attr.type ~= "error" and stanza.attr.type ~= "result" and st.reply(stanza)} };
 128         log("debug", "stanza [%s] queued until connection complete", tostring(stanza.name));
 129         s2sout.initiate_connection(host_session);
 130         if (not host_session.connecting) and (not host_session.conn) then
 131                 log("warn", "Connection to %s failed already, destroying session...", to_host);
 132                 s2s_destroy_session(host_session, "Connection failed");
 133                 return false;
 134         end
 135         return true;
 136 end
 137
 138 local function keepalive(event)
 139         return event.session.sends2s(' ');
 140 end
 141
 142 module:hook("s2s-read-timeout", keepalive, -1);
 143
 144 function module.add_host(module)
 145         if module:get_option_boolean("disallow_s2s", false) then
 146                 module:log("warn", "The 'disallow_s2s' config option is deprecated, please see http://prosody.im/doc/s2s#disabling");
 147                 return nil, "This host has disallow_s2s set";
 148         end
 149         module:hook("route/remote", route_to_existing_session, -1);
 150         module:hook("route/remote", route_to_new_session, -10);
 151         module:hook("s2s-authenticated", make_authenticated, -1);
 152         module:hook("s2s-read-timeout", keepalive, -1);
 153         module:hook_stanza("http://etherx.jabber.org/streams", "features", function (session, stanza)
 154                 if session.type == "s2sout" then
 155                         -- Stream is authenticated and we are seem to be done with feature negotiation,
 156                         -- so the stream is ready for stanzas.  RFC 6120 Section 4.3
 157                         mark_connected(session);
 158                         return true;
 159                 elseif not session.dialback_verifying then
 160                         session.log("warn", "No SASL EXTERNAL offer and Dialback doesn't seem to be enabled, giving up");
 161                         session:close();
 162                         return false;
 163                 end
 164         end, -1);
 165 end
 166
 167 -- Stream is authorised, and ready for normal stanzas
 168 function mark_connected(session)
 169         local sendq = session.sendq;
 170
 171         local from, to = session.from_host, session.to_host;
 172
 173         session.log("info", "%s s2s connection %s->%s complete", session.direction:gsub("^.", string.upper), from, to);
 174
 175         local event_data = { session = session };
 176         if session.type == "s2sout" then
 177                 fire_global_event("s2sout-established", event_data);
 178                 hosts[from].events.fire_event("s2sout-established", event_data);
 179         else
 180                 local host_session = hosts[to];
 181                 session.send = function(stanza)
 182                         return host_session.events.fire_event("route/remote", { from_host = to, to_host = from, stanza = stanza });
 183                 end;
 184
 185                 fire_global_event("s2sin-established", event_data);
 186                 hosts[to].events.fire_event("s2sin-established", event_data);
 187         end
 188
 189         if session.direction == "outgoing" then
 190                 if sendq then
 191                         session.log("debug", "sending %d queued stanzas across new outgoing connection to %s", #sendq, session.to_host);
 192                         local send = session.sends2s;
 193                         for i, data in ipairs(sendq) do
 194                                 send(data[1]);
 195                                 sendq[i] = nil;
 196                         end
 197                         session.sendq = nil;
 198                 end
 199
 200                 session.ip_hosts = nil;
 201                 session.srv_hosts = nil;
 202         end
 203 end
 204
 205 function make_authenticated(event)
 206         local session, host = event.session, event.host;
 207         if not session.secure then
 208                 if require_encryption or (secure_auth and not(insecure_domains[host])) or secure_domains[host] then
 209                         session:close({
 210                                 condition = "policy-violation",
 211                                 text = "Encrypted server-to-server communication is required but was not "
 212                                        ..((session.direction == "outgoing" and "offered") or "used")
 213                         });
 214                 end
 215         end
 216         if hosts[host] then
 217                 session:close({ condition = "undefined-condition", text = "Attempt to authenticate as a host we serve" });
 218         end
 219         if session.type == "s2sout_unauthed" then
 220                 session.type = "s2sout";
 221         elseif session.type == "s2sin_unauthed" then
 222                 session.type = "s2sin";
 223                 if host then
 224                         if not session.hosts[host] then session.hosts[host] = {}; end
 225                         session.hosts[host].authed = true;
 226                 end
 227         elseif session.type == "s2sin" and host then
 228                 if not session.hosts[host] then session.hosts[host] = {}; end
 229                 session.hosts[host].authed = true;
 230         else
 231                 return false;
 232         end
 233         session.log("debug", "connection %s->%s is now authenticated for %s", session.from_host, session.to_host, host);
 234
 235         if (session.type == "s2sout" and session.external_auth ~= "succeeded") or session.type == "s2sin" then
 236                 -- Stream either used dialback for authentication or is an incoming stream.
 237                 mark_connected(session);
 238         end
 239
 240         return true;
 241 end
 242
 243 --- Helper to check that a session peer's certificate is valid
 244 function check_cert_status(session)
 245         local host = session.direction == "outgoing" and session.to_host or session.from_host
 246         local conn = session.conn:socket()
 247         local cert
 248         if conn.getpeercertificate then
 249                 cert = conn:getpeercertificate()
 250         end
 251
 252         return module:fire_event("s2s-check-certificate", { host = host, session = session, cert = cert });
 253 end
 254
 255 --- XMPP stream event handlers
 256
 257 local stream_callbacks = { default_ns = "jabber:server", handlestanza =  core_process_stanza };
 258
 259 local xmlns_xmpp_streams = "urn:ietf:params:xml:ns:xmpp-streams";
 260
 261 function stream_callbacks.streamopened(session, attr)
 262         session.version = tonumber(attr.version) or 0;
 263
 264         -- TODO: Rename session.secure to session.encrypted
 265         if session.secure == false then
 266                 session.secure = true;
 267                 session.encrypted = true;
 268
 269                 local sock = session.conn:socket();
 270                 if sock.info then
 271                         local info = sock:info();
 272                         (session.log or log)("info", "Stream encrypted (%s with %s)", info.protocol, info.cipher);
 273                         session.compressed = info.compression;
 274                 else
 275                         (session.log or log)("info", "Stream encrypted");
 276                         session.compressed = sock.compression and sock:compression(); --COMPAT mw/luasec-hg
 277                 end
 278         end
 279
 280         if session.direction == "incoming" then
 281                 -- Send a reply stream header
 282
 283                 -- Validate to/from
 284                 local to, from = nameprep(attr.to), nameprep(attr.from);
 285                 if not to and attr.to then -- COMPAT: Some servers do not reliably set 'to' (especially on stream restarts)
 286                         session:close({ condition = "improper-addressing", text = "Invalid 'to' address" });
 287                         return;
 288                 end
 289                 if not from and attr.from then -- COMPAT: Some servers do not reliably set 'from' (especially on stream restarts)
 290                         session:close({ condition = "improper-addressing", text = "Invalid 'from' address" });
 291                         return;
 292                 end
 293
 294                 -- Set session.[from/to]_host if they have not been set already and if
 295                 -- this session isn't already authenticated
 296                 if session.type == "s2sin_unauthed" and from and not session.from_host then
 297                         session.from_host = from;
 298                 elseif from ~= session.from_host then
 299                         session:close({ condition = "improper-addressing", text = "New stream 'from' attribute does not match original" });
 300                         return;
 301                 end
 302                 if session.type == "s2sin_unauthed" and to and not session.to_host then
 303                         session.to_host = to;
 304                 elseif to ~= session.to_host then
 305                         session:close({ condition = "improper-addressing", text = "New stream 'to' attribute does not match original" });
 306                         return;
 307                 end
 308
 309                 -- For convenience we'll put the sanitised values into these variables
 310                 to, from = session.to_host, session.from_host;
 311
 312                 session.streamid = uuid_gen();
 313                 (session.log or log)("debug", "Incoming s2s received %s", st.stanza("stream:stream", attr):top_tag());
 314                 if to then
 315                         if not hosts[to] then
 316                                 -- Attempting to connect to a host we don't serve
 317                                 session:close({
 318                                         condition = "host-unknown";
 319                                         text = "This host does not serve "..to
 320                                 });
 321                                 return;
 322                         elseif not hosts[to].modules.s2s then
 323                                 -- Attempting to connect to a host that disallows s2s
 324                                 session:close({
 325                                         condition = "policy-violation";
 326                                         text = "Server-to-server communication is disabled for this host";
 327                                 });
 328                                 return;
 329                         end
 330                 end
 331
 332                 if hosts[from] then
 333                         session:close({ condition = "undefined-condition", text = "Attempt to connect from a host we serve" });
 334                         return;
 335                 end
 336
 337                 if session.secure and not session.cert_chain_status then
 338                         if check_cert_status(session) == false then
 339                                 return;
 340                         end
 341                 end
 342
 343                 session:open_stream(session.to_host, session.from_host)
 344                 session.notopen = nil;
 345                 if session.version >= 1.0 then
 346                         local features = st.stanza("stream:features");
 347
 348                         if to then
 349                                 hosts[to].events.fire_event("s2s-stream-features", { origin = session, features = features });
 350                         else
 351                                 (session.log or log)("warn", "No 'to' on stream header from %s means we can't offer any features", from or session.ip or "unknown host");
 352                                 fire_global_event("s2s-stream-features-legacy", { origin = session, features = features });
 353                         end
 354
 355                         if ( session.type == "s2sin" or session.type == "s2sout" ) or features.tags[1] then
 356                                 log("debug", "Sending stream features: %s", tostring(features));
 357                                 session.sends2s(features);
 358                         else
 359                                 (session.log or log)("warn", "No features to offer, giving up");
 360                                 session:close({ condition = "undefined-condition", text = "No features to offer" });
 361                         end
 362                 end
 363         elseif session.direction == "outgoing" then
 364                 session.notopen = nil;
 365                 if not attr.id then
 366                         log("error", "Stream response from %s did not give us a stream id!", session.to_host);
 367                         session:close({ condition = "undefined-condition", text = "Missing stream ID" });
 368                         return;
 369                 end
 370                 session.streamid = attr.id;
 371
 372                 if session.secure and not session.cert_chain_status then
 373                         if check_cert_status(session) == false then
 374                                 return;
 375                         end
 376                 end
 377
 378                 -- Send unauthed buffer
 379                 -- (stanzas which are fine to send before dialback)
 380                 -- Note that this is *not* the stanza queue (which
 381                 -- we can only send if auth succeeds) :)
 382                 local send_buffer = session.send_buffer;
 383                 if send_buffer and #send_buffer > 0 then
 384                         log("debug", "Sending s2s send_buffer now...");
 385                         for i, data in ipairs(send_buffer) do
 386                                 session.sends2s(tostring(data));
 387                                 send_buffer[i] = nil;
 388                         end
 389                 end
 390                 session.send_buffer = nil;
 391
 392                 -- If server is pre-1.0, don't wait for features, just do dialback
 393                 if session.version < 1.0 then
 394                         if not session.dialback_verifying then
 395                                 hosts[session.from_host].events.fire_event("s2sout-authenticate-legacy", { origin = session });
 396                         else
 397                                 mark_connected(session);
 398                         end
 399                 end
 400         end
 401 end
 402
 403 function stream_callbacks.streamclosed(session)
 404         (session.log or log)("debug", "Received </stream:stream>");
 405         session:close(false);
 406 end
 407
 408 function stream_callbacks.error(session, error, data)
 409         if error == "no-stream" then
 410                 session.log("debug", "Invalid opening stream header (%s)", (data:gsub("^([^\1]+)\1", "{%1}")));
 411                 session:close("invalid-namespace");
 412         elseif error == "parse-error" then
 413                 session.log("debug", "Server-to-server XML parse error: %s", tostring(error));
 414                 session:close("not-well-formed");
 415         elseif error == "stream-error" then
 416                 local condition, text = "undefined-condition";
 417                 for child in data:children() do
 418                         if child.attr.xmlns == xmlns_xmpp_streams then
 419                                 if child.name ~= "text" then
 420                                         condition = child.name;
 421                                 else
 422                                         text = child:get_text();
 423                                 end
 424                                 if condition ~= "undefined-condition" and text then
 425                                         break;
 426                                 end
 427                         end
 428                 end
 429                 text = condition .. (text and (" ("..text..")") or "");
 430                 session.log("info", "Session closed by remote with error: %s", text);
 431                 session:close(nil, text);
 432         end
 433 end
 434
 435 local function handleerr(err) log("error", "Traceback[s2s]: %s", traceback(tostring(err), 2)); end
 436 function stream_callbacks.handlestanza(session, stanza)
 437         stanza = session.filter("stanzas/in", stanza);
 438         if stanza then
 439                 return xpcall(function () return core_process_stanza(session, stanza) end, handleerr);
 440         end
 441 end
 442
 443 local listener = {};
 444
 445 --- Session methods
 446 local stream_xmlns_attr = {xmlns='urn:ietf:params:xml:ns:xmpp-streams'};
 447 local function session_close(session, reason, remote_reason)
 448         local log = session.log or log;
 449         if session.conn then
 450                 if session.notopen then
 451                         if session.direction == "incoming" then
 452                                 session:open_stream(session.to_host, session.from_host);
 453                         else
 454                                 session:open_stream(session.from_host, session.to_host);
 455                         end
 456                 end
 457                 if reason then -- nil == no err, initiated by us, false == initiated by remote
 458                         if type(reason) == "string" then -- assume stream error
 459                                 log("debug", "Disconnecting %s[%s], <stream:error> is: %s", session.host or session.ip or "(unknown host)", session.type, reason);
 460                                 session.sends2s(st.stanza("stream:error"):tag(reason, {xmlns = 'urn:ietf:params:xml:ns:xmpp-streams' }));
 461                         elseif type(reason) == "table" then
 462                                 if reason.condition then
 463                                         local stanza = st.stanza("stream:error"):tag(reason.condition, stream_xmlns_attr):up();
 464                                         if reason.text then
 465                                                 stanza:tag("text", stream_xmlns_attr):text(reason.text):up();
 466                                         end
 467                                         if reason.extra then
 468                                                 stanza:add_child(reason.extra);
 469                                         end
 470                                         log("debug", "Disconnecting %s[%s], <stream:error> is: %s", session.host or session.ip or "(unknown host)", session.type, tostring(stanza));
 471                                         session.sends2s(stanza);
 472                                 elseif reason.name then -- a stanza
 473                                         log("debug", "Disconnecting %s->%s[%s], <stream:error> is: %s", session.from_host or "(unknown host)", session.to_host or "(unknown host)", session.type, tostring(reason));
 474                                         session.sends2s(reason);
 475                                 end
 476                         end
 477                 end
 478
 479                 session.sends2s("</stream:stream>");
 480                 function session.sends2s() return false; end
 481
 482                 local reason = remote_reason or (reason and (reason.text or reason.condition)) or reason;
 483                 session.log("info", "%s s2s stream %s->%s closed: %s", session.direction:gsub("^.", string.upper), session.from_host or "(unknown host)", session.to_host or "(unknown host)", reason or "stream closed");
 484
 485                 -- Authenticated incoming stream may still be sending us stanzas, so wait for </stream:stream> from remote
 486                 local conn = session.conn;
 487                 if reason == nil and not session.notopen and session.type == "s2sin" then
 488                         add_task(stream_close_timeout, function ()
 489                                 if not session.destroyed then
 490                                         session.log("warn", "Failed to receive a stream close response, closing connection anyway...");
 491                                         s2s_destroy_session(session, reason);
 492                                         conn:close();
 493                                 end
 494                         end);
 495                 else
 496                         s2s_destroy_session(session, reason);
 497                         conn:close(); -- Close immediately, as this is an outgoing connection or is not authed
 498                 end
 499         end
 500 end
 501
 502 function session_stream_attrs(session, from, to, attr)
 503         if not from or (hosts[from] and hosts[from].modules.dialback) then
 504                 attr["xmlns:db"] = 'jabber:server:dialback';
 505         end
 506         if not from then
 507                 attr.from = '';
 508         end
 509         if not to then
 510                 attr.to = '';
 511         end
 512 end
 513
 514 -- Session initialization logic shared by incoming and outgoing
 515 local function initialize_session(session)
 516         local stream = new_xmpp_stream(session, stream_callbacks);
 517         local log = session.log or log;
 518         session.stream = stream;
 519
 520         session.notopen = true;
 521
 522         function session.reset_stream()
 523                 session.notopen = true;
 524                 session.streamid = nil;
 525                 session.stream:reset();
 526         end
 527
 528         session.stream_attrs = session_stream_attrs;
 529
 530         local filter = initialize_filters(session);
 531         local conn = session.conn;
 532         local w = conn.write;
 533
 534         function session.sends2s(t)
 535                 log("debug", "sending: %s", t.top_tag and t:top_tag() or t:match("^[^>]*>?"));
 536                 if t.name then
 537                         t = filter("stanzas/out", t);
 538                 end
 539                 if t then
 540                         t = filter("bytes/out", tostring(t));
 541                         if t then
 542                                 return w(conn, t);
 543                         end
 544                 end
 545         end
 546
 547         function session.data(data)
 548                 data = filter("bytes/in", data);
 549                 if data then
 550                         local ok, err = stream:feed(data);
 551                         if ok then return; end
 552                         log("warn", "Received invalid XML: %s", data);
 553                         log("warn", "Problem was: %s", err);
 554                         session:close("not-well-formed");
 555                 end
 556         end
 557
 558         session.close = session_close;
 559
 560         local handlestanza = stream_callbacks.handlestanza;
 561         function session.dispatch_stanza(session, stanza)
 562                 return handlestanza(session, stanza);
 563         end
 564
 565         module:fire_event("s2s-created", { session = session });
 566
 567         add_task(connect_timeout, function ()
 568                 if session.type == "s2sin" or session.type == "s2sout" then
 569                         return; -- Ok, we're connected
 570                 elseif session.type == "s2s_destroyed" then
 571                         return; -- Session already destroyed
 572                 end
 573                 -- Not connected, need to close session and clean up
 574                 (session.log or log)("debug", "Destroying incomplete session %s->%s due to inactivity",
 575                 session.from_host or "(unknown)", session.to_host or "(unknown)");
 576                 session:close("connection-timeout");
 577         end);
 578 end
 579
 580 function listener.onconnect(conn)
 581         measure_connections(1);
 582         conn:setoption("keepalive", opt_keepalives);
 583         local session = sessions[conn];
 584         if not session then -- New incoming connection
 585                 session = s2s_new_incoming(conn);
 586                 sessions[conn] = session;
 587                 session.log("debug", "Incoming s2s connection");
 588                 initialize_session(session);
 589         else -- Outgoing session connected
 590                 session:open_stream(session.from_host, session.to_host);
 591         end
 592         session.ip = conn:ip();
 593 end
 594
 595 function listener.onincoming(conn, data)
 596         local session = sessions[conn];
 597         if session then
 598                 session.data(data);
 599         end
 600 end
 601
 602 function listener.onstatus(conn, status)
 603         if status == "ssl-handshake-complete" then
 604                 local session = sessions[conn];
 605                 if session and session.direction == "outgoing" then
 606                         session.log("debug", "Sending stream header...");
 607                         session:open_stream(session.from_host, session.to_host);
 608                 end
 609         end
 610 end
 611
 612 function listener.ontimeout(conn)
 613         -- Called instead of onconnect when the connection times out
 614         measure_connections(1);
 615 end
 616
 617 function listener.ondisconnect(conn, err)
 618         measure_connections(-1);
 619         local session = sessions[conn];
 620         if session then
 621                 sessions[conn] = nil;
 622                 if err and session.direction == "outgoing" and session.notopen then
 623                         (session.log or log)("debug", "s2s connection attempt failed: %s", err);
 624                         if s2sout.attempt_connection(session, err) then
 625                                 return; -- Session lives for now
 626                         end
 627                 end
 628                 (session.log or log)("debug", "s2s disconnected: %s->%s (%s)", tostring(session.from_host), tostring(session.to_host), tostring(err or "connection closed"));
 629                 s2s_destroy_session(session, err);
 630         end
 631 end
 632
 633 function listener.onreadtimeout(conn)
 634         local session = sessions[conn];
 635         local host = session.host or session.to_host;
 636         if session then
 637                 return (hosts[host] or prosody).events.fire_event("s2s-read-timeout", { session = session });
 638         end
 639 end
 640
 641 function listener.register_outgoing(conn, session)
 642         sessions[conn] = session;
 643         initialize_session(session);
 644 end
 645
 646 function listener.ondetach(conn)
 647         sessions[conn] = nil;
 648 end
 649
 650 function check_auth_policy(event)
 651         local host, session = event.host, event.session;
 652         local must_secure = secure_auth;
 653
 654         if not must_secure and secure_domains[host] then
 655                 must_secure = true;
 656         elseif must_secure and insecure_domains[host] then
 657                 must_secure = false;
 658         end
 659
 660         if must_secure and (session.cert_chain_status ~= "valid" or session.cert_identity_status ~= "valid") then
 661                 module:log("warn", "Forbidding insecure connection to/from %s", host or session.ip or "(unknown host)");
 662                 if session.direction == "incoming" then
 663                         session:close({ condition = "not-authorized", text = "Your server's certificate is invalid, expired, or not trusted by "..session.to_host });
 664                 else -- Close outgoing connections without warning
 665                         session:close(false);
 666                 end
 667                 return false;
 668         end
 669 end
 670
 671 module:hook("s2s-check-certificate", check_auth_policy, -1);
 672
 673 s2sout.set_listener(listener);
 674
 675 module:hook("server-stopping", function(event)
 676         local reason = event.reason;
 677         for _, session in pairs(sessions) do
 678                 session:close{ condition = "system-shutdown", text = reason };
 679         end
 680 end, -200);
 681
 682
 683
 684 module:provides("net", {
 685         name = "s2s";
 686         listener = listener;
 687         default_port = 5269;
 688         encryption = "starttls";
 689         multiplex = {
 690                 pattern = "^<.*:stream.*%sxmlns%s*=%s*(['\"])jabber:server%1.*>";
 691         };
 692 });
 693