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 local NULL = {};
  19
  20 local add_task = require "util.timer".add_task;
  21 local st = require "util.stanza";
  22 local initialize_filters = require "util.filters".initialize;
  23 local nameprep = require "util.encodings".stringprep.nameprep;
  24 local new_xmpp_stream = require "util.xmppstream".new;
  25 local s2s_new_incoming = require "core.s2smanager".new_incoming;
  26 local s2s_new_outgoing = require "core.s2smanager".new_outgoing;
  27 local s2s_destroy_session = require "core.s2smanager".destroy_session;
  28 local uuid_gen = require "util.uuid".generate;
  29 local cert_verify_identity = require "util.x509".verify_identity;
  30 local fire_global_event = prosody.events.fire_event;
  31
  32 local s2sout = module:require("s2sout");
  33
  34 local connect_timeout = module:get_option_number("s2s_timeout", 90);
  35 local stream_close_timeout = module:get_option_number("s2s_close_timeout", 5);
  36 local opt_keepalives = module:get_option_boolean("s2s_tcp_keepalives", module:get_option_boolean("tcp_keepalives", true));
  37 local secure_auth = module:get_option_boolean("s2s_secure_auth", false); -- One day...
  38 local secure_domains, insecure_domains =
  39         module:get_option_set("s2s_secure_domains", {})._items, module:get_option_set("s2s_insecure_domains", {})._items;
  40 local require_encryption = module:get_option_boolean("s2s_require_encryption", false);
  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 function module.add_host(module)
 139         if module:get_option_boolean("disallow_s2s", false) then
 140                 module:log("warn", "The 'disallow_s2s' config option is deprecated, please see http://prosody.im/doc/s2s#disabling");
 141                 return nil, "This host has disallow_s2s set";
 142         end
 143         module:hook("route/remote", route_to_existing_session, -1);
 144         module:hook("route/remote", route_to_new_session, -10);
 145         module:hook("s2s-authenticated", make_authenticated, -1);
 146 end
 147
 148 -- Stream is authorised, and ready for normal stanzas
 149 function mark_connected(session)
 150         local sendq = session.sendq;
 151
 152         local from, to = session.from_host, session.to_host;
 153
 154         session.log("info", "%s s2s connection %s->%s complete", session.direction, from, to);
 155
 156         local event_data = { session = session };
 157         if session.type == "s2sout" then
 158                 fire_global_event("s2sout-established", event_data);
 159                 hosts[from].events.fire_event("s2sout-established", event_data);
 160         else
 161                 local host_session = hosts[to];
 162                 session.send = function(stanza)
 163                         return host_session.events.fire_event("route/remote", { from_host = to, to_host = from, stanza = stanza });
 164                 end;
 165
 166                 fire_global_event("s2sin-established", event_data);
 167                 hosts[to].events.fire_event("s2sin-established", event_data);
 168         end
 169
 170         if session.direction == "outgoing" then
 171                 if sendq then
 172                         session.log("debug", "sending %d queued stanzas across new outgoing connection to %s", #sendq, session.to_host);
 173                         local send = session.sends2s;
 174                         for i, data in ipairs(sendq) do
 175                                 send(data[1]);
 176                                 sendq[i] = nil;
 177                         end
 178                         session.sendq = nil;
 179                 end
 180
 181                 session.ip_hosts = nil;
 182                 session.srv_hosts = nil;
 183         end
 184 end
 185
 186 function make_authenticated(event)
 187         local session, host = event.session, event.host;
 188         if not session.secure then
 189                 if require_encryption or (secure_auth and not(insecure_domains[host])) or secure_domains[host] then
 190                         session:close({
 191                                 condition = "policy-violation",
 192                                 text = "Encrypted server-to-server communication is required but was not "
 193                                        ..((session.direction == "outgoing" and "offered") or "used")
 194                         });
 195                 end
 196         end
 197         if hosts[host] then
 198                 session:close({ condition = "undefined-condition", text = "Attempt to authenticate as a host we serve" });
 199         end
 200         if session.type == "s2sout_unauthed" then
 201                 session.type = "s2sout";
 202         elseif session.type == "s2sin_unauthed" then
 203                 session.type = "s2sin";
 204                 if host then
 205                         if not session.hosts[host] then session.hosts[host] = {}; end
 206                         session.hosts[host].authed = true;
 207                 end
 208         elseif session.type == "s2sin" and host then
 209                 if not session.hosts[host] then session.hosts[host] = {}; end
 210                 session.hosts[host].authed = true;
 211         else
 212                 return false;
 213         end
 214         session.log("debug", "connection %s->%s is now authenticated for %s", session.from_host, session.to_host, host);
 215
 216         mark_connected(session);
 217
 218         return true;
 219 end
 220
 221 --- Helper to check that a session peer's certificate is valid
 222 local function check_cert_status(session)
 223         local host = session.direction == "outgoing" and session.to_host or session.from_host
 224         local conn = session.conn:socket()
 225         local cert
 226         if conn.getpeercertificate then
 227                 cert = conn:getpeercertificate()
 228         end
 229
 230         if cert then
 231                 local chain_valid, errors;
 232                 if conn.getpeerverification then
 233                         chain_valid, errors = conn:getpeerverification();
 234                 elseif conn.getpeerchainvalid then -- COMPAT mw/luasec-hg
 235                         chain_valid, errors = conn:getpeerchainvalid();
 236                         errors = (not chain_valid) and { { errors } } or nil;
 237                 else
 238                         chain_valid, errors = false, { { "Chain verification not supported by this version of LuaSec" } };
 239                 end
 240                 -- Is there any interest in printing out all/the number of errors here?
 241                 if not chain_valid then
 242                         (session.log or log)("debug", "certificate chain validation result: invalid");
 243                         for depth, t in pairs(errors or NULL) do
 244                                 (session.log or log)("debug", "certificate error(s) at depth %d: %s", depth-1, table.concat(t, ", "))
 245                         end
 246                         session.cert_chain_status = "invalid";
 247                 else
 248                         (session.log or log)("debug", "certificate chain validation result: valid");
 249                         session.cert_chain_status = "valid";
 250
 251                         -- We'll go ahead and verify the asserted identity if the
 252                         -- connecting server specified one.
 253                         if host then
 254                                 if cert_verify_identity(host, "xmpp-server", cert) then
 255                                         session.cert_identity_status = "valid"
 256                                 else
 257                                         session.cert_identity_status = "invalid"
 258                                 end
 259                                 (session.log or log)("debug", "certificate identity validation result: %s", session.cert_identity_status);
 260                         end
 261                 end
 262         end
 263         return module:fire_event("s2s-check-certificate", { host = host, session = session, cert = cert });
 264 end
 265
 266 --- XMPP stream event handlers
 267
 268 local stream_callbacks = { default_ns = "jabber:server", handlestanza =  core_process_stanza };
 269
 270 local xmlns_xmpp_streams = "urn:ietf:params:xml:ns:xmpp-streams";
 271
 272 function stream_callbacks.streamopened(session, attr)
 273         session.version = tonumber(attr.version) or 0;
 274
 275         -- TODO: Rename session.secure to session.encrypted
 276         if session.secure == false then
 277                 session.secure = true;
 278
 279                 -- Check if TLS compression is used
 280                 local sock = session.conn:socket();
 281                 if sock.info then
 282                         session.compressed = sock:info"compression";
 283                 elseif sock.compression then
 284                         session.compressed = sock:compression(); --COMPAT mw/luasec-hg
 285                 end
 286         end
 287
 288         if session.direction == "incoming" then
 289                 -- Send a reply stream header
 290
 291                 -- Validate to/from
 292                 local to, from = nameprep(attr.to), nameprep(attr.from);
 293                 if not to and attr.to then -- COMPAT: Some servers do not reliably set 'to' (especially on stream restarts)
 294                         session:close({ condition = "improper-addressing", text = "Invalid 'to' address" });
 295                         return;
 296                 end
 297                 if not from and attr.from then -- COMPAT: Some servers do not reliably set 'from' (especially on stream restarts)
 298                         session:close({ condition = "improper-addressing", text = "Invalid 'from' address" });
 299                         return;
 300                 end
 301
 302                 -- Set session.[from/to]_host if they have not been set already and if
 303                 -- this session isn't already authenticated
 304                 if session.type == "s2sin_unauthed" and from and not session.from_host then
 305                         session.from_host = from;
 306                 elseif from ~= session.from_host then
 307                         session:close({ condition = "improper-addressing", text = "New stream 'from' attribute does not match original" });
 308                         return;
 309                 end
 310                 if session.type == "s2sin_unauthed" and to and not session.to_host then
 311                         session.to_host = to;
 312                 elseif to ~= session.to_host then
 313                         session:close({ condition = "improper-addressing", text = "New stream 'to' attribute does not match original" });
 314                         return;
 315                 end
 316
 317                 -- For convenience we'll put the sanitised values into these variables
 318                 to, from = session.to_host, session.from_host;
 319
 320                 session.streamid = uuid_gen();
 321                 (session.log or log)("debug", "Incoming s2s received %s", st.stanza("stream:stream", attr):top_tag());
 322                 if to then
 323                         if not hosts[to] then
 324                                 -- Attempting to connect to a host we don't serve
 325                                 session:close({
 326                                         condition = "host-unknown";
 327                                         text = "This host does not serve "..to
 328                                 });
 329                                 return;
 330                         elseif not hosts[to].modules.s2s then
 331                                 -- Attempting to connect to a host that disallows s2s
 332                                 session:close({
 333                                         condition = "policy-violation";
 334                                         text = "Server-to-server communication is disabled for this host";
 335                                 });
 336                                 return;
 337                         end
 338                 end
 339
 340                 if hosts[from] then
 341                         session:close({ condition = "undefined-condition", text = "Attempt to connect from a host we serve" });
 342                         return;
 343                 end
 344
 345                 if session.secure and not session.cert_chain_status then
 346                         if check_cert_status(session) == false then
 347                                 return;
 348                         end
 349                 end
 350
 351                 session:open_stream(session.to_host, session.from_host)
 352                 session.notopen = nil;
 353                 if session.version >= 1.0 then
 354                         local features = st.stanza("stream:features");
 355
 356                         if to then
 357                                 hosts[to].events.fire_event("s2s-stream-features", { origin = session, features = features });
 358                         else
 359                                 (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");
 360                         end
 361
 362                         log("debug", "Sending stream features: %s", tostring(features));
 363                         session.sends2s(features);
 364                 end
 365         elseif session.direction == "outgoing" then
 366                 session.notopen = nil;
 367                 if not attr.id then
 368                         log("error", "Stream response did not give us a stream id!");
 369                         session:close({ condition = "undefined-condition", text = "Missing stream ID" });
 370                         return;
 371                 end
 372                 session.streamid = attr.id;
 373
 374                 if session.secure and not session.cert_chain_status then
 375                         if check_cert_status(session) == false then
 376                                 return;
 377                         end
 378                 end
 379
 380                 -- Send unauthed buffer
 381                 -- (stanzas which are fine to send before dialback)
 382                 -- Note that this is *not* the stanza queue (which
 383                 -- we can only send if auth succeeds) :)
 384                 local send_buffer = session.send_buffer;
 385                 if send_buffer and #send_buffer > 0 then
 386                         log("debug", "Sending s2s send_buffer now...");
 387                         for i, data in ipairs(send_buffer) do
 388                                 session.sends2s(tostring(data));
 389                                 send_buffer[i] = nil;
 390                         end
 391                 end
 392                 session.send_buffer = nil;
 393
 394                 -- If server is pre-1.0, don't wait for features, just do dialback
 395                 if session.version < 1.0 then
 396                         if not session.dialback_verifying then
 397                                 hosts[session.from_host].events.fire_event("s2sout-authenticate-legacy", { origin = session });
 398                         else
 399                                 mark_connected(session);
 400                         end
 401                 end
 402         end
 403 end
 404
 405 function stream_callbacks.streamclosed(session)
 406         (session.log or log)("debug", "Received </stream:stream>");
 407         session:close(false);
 408 end
 409
 410 function stream_callbacks.error(session, error, data)
 411         if error == "no-stream" then
 412                 session.log("debug", "Invalid opening stream header (%s)", (data:gsub("^([^\1]+)\1", "{%1}")));
 413                 session:close("invalid-namespace");
 414         elseif error == "parse-error" then
 415                 session.log("debug", "Server-to-server XML parse error: %s", tostring(error));
 416                 session:close("not-well-formed");
 417         elseif error == "stream-error" then
 418                 local condition, text = "undefined-condition";
 419                 for child in data:children() do
 420                         if child.attr.xmlns == xmlns_xmpp_streams then
 421                                 if child.name ~= "text" then
 422                                         condition = child.name;
 423                                 else
 424                                         text = child:get_text();
 425                                 end
 426                                 if condition ~= "undefined-condition" and text then
 427                                         break;
 428                                 end
 429                         end
 430                 end
 431                 text = condition .. (text and (" ("..text..")") or "");
 432                 session.log("info", "Session closed by remote with error: %s", text);
 433                 session:close(nil, text);
 434         end
 435 end
 436
 437 local function handleerr(err) log("error", "Traceback[s2s]: %s", traceback(tostring(err), 2)); end
 438 function stream_callbacks.handlestanza(session, stanza)
 439         if stanza.attr.xmlns == "jabber:client" then --COMPAT: Prosody pre-0.6.2 may send jabber:client
 440                 stanza.attr.xmlns = nil;
 441         end
 442         stanza = session.filter("stanzas/in", stanza);
 443         if stanza then
 444                 return xpcall(function () return core_process_stanza(session, stanza) end, handleerr);
 445         end
 446 end
 447
 448 local listener = {};
 449
 450 --- Session methods
 451 local stream_xmlns_attr = {xmlns='urn:ietf:params:xml:ns:xmpp-streams'};
 452 local function session_close(session, reason, remote_reason)
 453         local log = session.log or log;
 454         if session.conn then
 455                 if session.notopen then
 456                         if session.direction == "incoming" then
 457                                 session:open_stream(session.to_host, session.from_host);
 458                         else
 459                                 session:open_stream(session.from_host, session.to_host);
 460                         end
 461                 end
 462                 if reason then -- nil == no err, initiated by us, false == initiated by remote
 463                         if type(reason) == "string" then -- assume stream error
 464                                 log("debug", "Disconnecting %s[%s], <stream:error> is: %s", session.host or session.ip or "(unknown host)", session.type, reason);
 465                                 session.sends2s(st.stanza("stream:error"):tag(reason, {xmlns = 'urn:ietf:params:xml:ns:xmpp-streams' }));
 466                         elseif type(reason) == "table" then
 467                                 if reason.condition then
 468                                         local stanza = st.stanza("stream:error"):tag(reason.condition, stream_xmlns_attr):up();
 469                                         if reason.text then
 470                                                 stanza:tag("text", stream_xmlns_attr):text(reason.text):up();
 471                                         end
 472                                         if reason.extra then
 473                                                 stanza:add_child(reason.extra);
 474                                         end
 475                                         log("debug", "Disconnecting %s[%s], <stream:error> is: %s", session.host or session.ip or "(unknown host)", session.type, tostring(stanza));
 476                                         session.sends2s(stanza);
 477                                 elseif reason.name then -- a stanza
 478                                         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));
 479                                         session.sends2s(reason);
 480                                 end
 481                         end
 482                 end
 483
 484                 session.sends2s("</stream:stream>");
 485                 function session.sends2s() return false; end
 486
 487                 local reason = remote_reason or (reason and (reason.text or reason.condition)) or reason;
 488                 session.log("info", "%s s2s stream %s->%s closed: %s", session.direction, session.from_host or "(unknown host)", session.to_host or "(unknown host)", reason or "stream closed");
 489
 490                 -- Authenticated incoming stream may still be sending us stanzas, so wait for </stream:stream> from remote
 491                 local conn = session.conn;
 492                 if reason == nil and not session.notopen and session.type == "s2sin" then
 493                         add_task(stream_close_timeout, function ()
 494                                 if not session.destroyed then
 495                                         session.log("warn", "Failed to receive a stream close response, closing connection anyway...");
 496                                         s2s_destroy_session(session, reason);
 497                                         conn:close();
 498                                 end
 499                         end);
 500                 else
 501                         s2s_destroy_session(session, reason);
 502                         conn:close(); -- Close immediately, as this is an outgoing connection or is not authed
 503                 end
 504         end
 505 end
 506
 507 function session_open_stream(session, from, to)
 508         local attr = {
 509                 ["xmlns:stream"] = 'http://etherx.jabber.org/streams',
 510                 xmlns = 'jabber:server',
 511                 version = session.version and (session.version > 0 and "1.0" or nil),
 512                 ["xml:lang"] = 'en',
 513                 id = session.streamid,
 514                 from = from or "", to = to or "",
 515         }
 516         if not from or (hosts[from] and hosts[from].modules.dialback) then
 517                 attr["xmlns:db"] = 'jabber:server:dialback';
 518         end
 519
 520         session.sends2s("<?xml version='1.0'?>");
 521         session.sends2s(st.stanza("stream:stream", attr):top_tag());
 522         return true;
 523 end
 524
 525 -- Session initialization logic shared by incoming and outgoing
 526 local function initialize_session(session)
 527         local stream = new_xmpp_stream(session, stream_callbacks);
 528         session.stream = stream;
 529
 530         session.notopen = true;
 531
 532         function session.reset_stream()
 533                 session.notopen = true;
 534                 session.streamid = nil;
 535                 session.stream:reset();
 536         end
 537
 538         session.open_stream = session_open_stream;
 539
 540         local filter = session.filter;
 541         function session.data(data)
 542                 data = filter("bytes/in", data);
 543                 if data then
 544                         local ok, err = stream:feed(data);
 545                         if ok then return; end
 546                         (session.log or log)("warn", "Received invalid XML: %s", data);
 547                         (session.log or log)("warn", "Problem was: %s", err);
 548                         session:close("not-well-formed");
 549                 end
 550         end
 551
 552         session.close = session_close;
 553
 554         local handlestanza = stream_callbacks.handlestanza;
 555         function session.dispatch_stanza(session, stanza)
 556                 return handlestanza(session, stanza);
 557         end
 558
 559         add_task(connect_timeout, function ()
 560                 if session.type == "s2sin" or session.type == "s2sout" then
 561                         return; -- Ok, we're connected
 562                 elseif session.type == "s2s_destroyed" then
 563                         return; -- Session already destroyed
 564                 end
 565                 -- Not connected, need to close session and clean up
 566                 (session.log or log)("debug", "Destroying incomplete session %s->%s due to inactivity",
 567                 session.from_host or "(unknown)", session.to_host or "(unknown)");
 568                 session:close("connection-timeout");
 569         end);
 570 end
 571
 572 function listener.onconnect(conn)
 573         conn:setoption("keepalive", opt_keepalives);
 574         local session = sessions[conn];
 575         if not session then -- New incoming connection
 576                 session = s2s_new_incoming(conn);
 577                 sessions[conn] = session;
 578                 session.log("debug", "Incoming s2s connection");
 579
 580                 local filter = initialize_filters(session);
 581                 local w = conn.write;
 582                 session.sends2s = function (t)
 583                         log("debug", "sending: %s", t.top_tag and t:top_tag() or t:match("^([^>]*>?)"));
 584                         if t.name then
 585                                 t = filter("stanzas/out", t);
 586                         end
 587                         if t then
 588                                 t = filter("bytes/out", tostring(t));
 589                                 if t then
 590                                         return w(conn, t);
 591                                 end
 592                         end
 593                 end
 594
 595                 initialize_session(session);
 596         else -- Outgoing session connected
 597                 session:open_stream(session.from_host, session.to_host);
 598         end
 599 end
 600
 601 function listener.onincoming(conn, data)
 602         local session = sessions[conn];
 603         if session then
 604                 session.data(data);
 605         end
 606 end
 607
 608 function listener.onstatus(conn, status)
 609         if status == "ssl-handshake-complete" then
 610                 local session = sessions[conn];
 611                 if session and session.direction == "outgoing" then
 612                         session.log("debug", "Sending stream header...");
 613                         session:open_stream(session.from_host, session.to_host);
 614                 end
 615         end
 616 end
 617
 618 function listener.ondisconnect(conn, err)
 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                                 (session.log or log)("debug", "...so we're going to try another target");
 626                                 return; -- Session lives for now
 627                         end
 628                 end
 629                 (session.log or log)("debug", "s2s disconnected: %s->%s (%s)", tostring(session.from_host), tostring(session.to_host), tostring(err or "connection closed"));
 630                 s2s_destroy_session(session, err);
 631         end
 632 end
 633
 634 function listener.register_outgoing(conn, session)
 635         session.direction = "outgoing";
 636         sessions[conn] = session;
 637         initialize_session(session);
 638 end
 639
 640 function listener.ondetach(conn)
 641         sessions[conn] = nil;
 642 end
 643
 644 function check_auth_policy(event)
 645         local host, session = event.host, event.session;
 646         local must_secure = secure_auth;
 647
 648         if not must_secure and secure_domains[host] then
 649                 must_secure = true;
 650         elseif must_secure and insecure_domains[host] then
 651                 must_secure = false;
 652         end
 653
 654         if must_secure and (session.cert_chain_status ~= "valid" or session.cert_identity_status ~= "valid") then
 655                 module:log("warn", "Forbidding insecure connection to/from %s", host or session.ip or "(unknown host)");
 656                 if session.direction == "incoming" then
 657                         session:close({ condition = "not-authorized", text = "Your server's certificate is invalid, expired, or not trusted by "..session.to_host });
 658                 else -- Close outgoing connections without warning
 659                         session:close(false);
 660                 end
 661                 return false;
 662         end
 663 end
 664
 665 module:hook("s2s-check-certificate", check_auth_policy, -1);
 666
 667 s2sout.set_listener(listener);
 668
 669 module:hook("server-stopping", function(event)
 670         local reason = event.reason;
 671         for _, session in pairs(sessions) do
 672                 session:close{ condition = "system-shutdown", text = reason };
 673         end
 674 end, -200);
 675
 676
 677
 678 module:provides("net", {
 679         name = "s2s";
 680         listener = listener;
 681         default_port = 5269;
 682         encryption = "starttls";
 683         multiplex = {
 684                 pattern = "^<.*:stream.*%sxmlns%s*=%s*(['\"])jabber:server%1.*>";
 685         };
 686 });
 687