2 -- Copyright (C) 2008-2010 Matthew Wild
3 -- Copyright (C) 2008-2010 Waqas Hussain
5 -- This project is MIT/X11 licensed. Please see the
6 -- COPYING file in the source package for more information.
12 local sessions = sessions;
13 local core_process_stanza = function(a, b) core_process_stanza(a, b); end
14 local add_task = require "util.timer".add_task;
15 local socket = require "socket";
16 local format = string.format;
17 local t_insert, t_sort = table.insert, table.sort;
18 local get_traceback = debug.traceback;
19 local tostring, pairs, ipairs, getmetatable, newproxy, error, tonumber, setmetatable
20 = tostring, pairs, ipairs, getmetatable, newproxy, error, tonumber, setmetatable;
22 local idna_to_ascii = require "util.encodings".idna.to_ascii;
23 local connlisteners_get = require "net.connlisteners".get;
24 local initialize_filters = require "util.filters".initialize;
25 local wrapclient = require "net.server".wrapclient;
26 local modulemanager = require "core.modulemanager";
27 local st = require "stanza";
28 local stanza = st.stanza;
29 local nameprep = require "util.encodings".stringprep.nameprep;
30 local cert_verify_identity = require "util.x509".verify_identity;
32 local fire_event = prosody.events.fire_event;
33 local uuid_gen = require "util.uuid".generate;
35 local logger_init = require "util.logger".init;
37 local log = logger_init("s2smanager");
39 local sha256_hash = require "util.hashes".sha256;
41 local adns, dns = require "net.adns", require "net.dns";
42 local config = require "core.configmanager";
43 local connect_timeout = config.get("*", "core", "s2s_timeout") or 60;
44 local dns_timeout = config.get("*", "core", "dns_timeout") or 15;
45 local max_dns_depth = config.get("*", "core", "dns_max_depth") or 3;
47 dns.settimeout(dns_timeout);
49 local prosody = _G.prosody;
51 prosody.incoming_s2s = incoming_s2s;
52 local incoming_s2s = incoming_s2s;
56 function compare_srv_priorities(a,b)
57 return a.priority < b.priority or (a.priority == b.priority and a.weight > b.weight);
60 local bouncy_stanzas = { message = true, presence = true, iq = true };
61 local function bounce_sendq(session, reason)
62 local sendq = session.sendq;
64 session.log("info", "sending error replies for "..#sendq.." queued stanzas because of failed outgoing connection to "..tostring(session.to_host));
68 (session.log or log)("error", "Replying to to an s2s error reply, please report this! Traceback: %s", get_traceback());
72 for i, data in ipairs(sendq) do
73 local reply = data[2];
74 if reply and not(reply.attr.xmlns) and bouncy_stanzas[reply.name] then
75 reply.attr.type = "error";
76 reply:tag("error", {type = "cancel"})
77 :tag("remote-server-not-found", {xmlns = "urn:ietf:params:xml:ns:xmpp-stanzas"}):up();
79 reply:tag("text", {xmlns = "urn:ietf:params:xml:ns:xmpp-stanzas"})
80 :text("Server-to-server connection failed: "..reason):up();
82 core_process_stanza(dummy, reply);
90 function send_to_host(from_host, to_host, data)
91 if not hosts[from_host] then
92 log("warn", "Attempt to send stanza from %s - a host we don't serve", from_host);
95 local host = hosts[from_host].s2sout[to_host];
97 -- We have a connection to this host already
98 if host.type == "s2sout_unauthed" and (data.name ~= "db:verify" or not host.dialback_key) then
99 (host.log or log)("debug", "trying to send over unauthed s2sout to "..to_host);
101 -- Queue stanza until we are able to send it
102 if host.sendq then t_insert(host.sendq, {tostring(data), data.attr.type ~= "error" and data.attr.type ~= "result" and st.reply(data)});
103 else host.sendq = { {tostring(data), data.attr.type ~= "error" and data.attr.type ~= "result" and st.reply(data)} }; end
104 host.log("debug", "stanza [%s] queued ", data.name);
105 elseif host.type == "local" or host.type == "component" then
106 log("error", "Trying to send a stanza to ourselves??")
107 log("error", "Traceback: %s", get_traceback());
108 log("error", "Stanza: %s", tostring(data));
111 (host.log or log)("debug", "going to send stanza to "..to_host.." from "..from_host);
113 if host.from_host ~= from_host then
114 log("error", "WARNING! This might, possibly, be a bug, but it might not...");
115 log("error", "We are going to send from %s instead of %s", tostring(host.from_host), tostring(from_host));
118 host.log("debug", "stanza sent over "..host.type);
121 log("debug", "opening a new outgoing connection for this stanza");
122 local host_session = new_outgoing(from_host, to_host);
125 host_session.sendq = { {tostring(data), data.attr.type ~= "error" and data.attr.type ~= "result" and st.reply(data)} };
126 log("debug", "stanza [%s] queued until connection complete", tostring(data.name));
127 if (not host_session.connecting) and (not host_session.conn) then
128 log("warn", "Connection to %s failed already, destroying session...", to_host);
129 if not destroy_session(host_session, "Connection failed") then
130 -- Already destroyed, we need to bounce our stanza
131 bounce_sendq(host_session, host_session.destruction_reason);
139 local open_sessions = 0;
141 function new_incoming(conn)
142 local session = { conn = conn, type = "s2sin_unauthed", direction = "incoming", hosts = {} };
144 session.trace = newproxy(true);
145 getmetatable(session.trace).__gc = function () open_sessions = open_sessions - 1; end;
147 open_sessions = open_sessions + 1;
148 local w, log = conn.write, logger_init("s2sin"..tostring(conn):match("[a-f0-9]+$"));
150 local filter = initialize_filters(session);
151 session.sends2s = function (t)
152 log("debug", "sending: %s", t.top_tag and t:top_tag() or t:match("^([^>]*>?)"));
154 t = filter("stanzas/out", t);
157 t = filter("bytes/out", tostring(t));
163 incoming_s2s[session] = true;
164 add_task(connect_timeout, function ()
165 if session.conn ~= conn or
166 session.type == "s2sin" then
167 return; -- Ok, we're connect[ed|ing]
169 -- Not connected, need to close session and clean up
170 (session.log or log)("warn", "Destroying incomplete session %s->%s due to inactivity",
171 session.from_host or "(unknown)", session.to_host or "(unknown)");
172 session:close("connection-timeout");
177 function new_outgoing(from_host, to_host, connect)
178 local host_session = { to_host = to_host, from_host = from_host, host = from_host,
179 notopen = true, type = "s2sout_unauthed", direction = "outgoing",
180 open_stream = session_open_stream };
182 hosts[from_host].s2sout[to_host] = host_session;
184 host_session.close = destroy_session; -- This gets replaced by xmppserver_listener later
188 local conn_name = "s2sout"..tostring(host_session):match("[a-f0-9]*$");
189 log = logger_init(conn_name);
190 host_session.log = log;
193 initialize_filters(host_session);
195 if connect ~= false then
196 -- Kick the connection attempting machine into life
197 if not attempt_connection(host_session) then
198 -- Intentionally not returning here, the
199 -- session is needed, connected or not
200 destroy_session(host_session);
204 if not host_session.sends2s then
205 -- A sends2s which buffers data (until the stream is opened)
206 -- note that data in this buffer will be sent before the stream is authed
207 -- and will not be ack'd in any way, successful or otherwise
209 function host_session.sends2s(data)
212 host_session.send_buffer = buffer;
214 log("debug", "Buffering data on unconnected s2sout to %s", to_host);
215 buffer[#buffer+1] = data;
216 log("debug", "Buffered item %d: %s", #buffer, tostring(data));
224 function attempt_connection(host_session, err)
225 local from_host, to_host = host_session.from_host, host_session.to_host;
226 local connect_host, connect_port = to_host and idna_to_ascii(to_host), 5269;
228 if not connect_host then
232 if not err then -- This is our first attempt
233 log("debug", "First attempt to connect to %s, starting with SRV lookup...", to_host);
234 host_session.connecting = true;
236 handle = adns.lookup(function (answer)
238 host_session.connecting = nil;
240 log("debug", to_host.." has SRV records, handling...");
241 local srv_hosts = {};
242 host_session.srv_hosts = srv_hosts;
243 for _, record in ipairs(answer) do
244 t_insert(srv_hosts, record.srv);
246 t_sort(srv_hosts, compare_srv_priorities);
248 local srv_choice = srv_hosts[1];
249 host_session.srv_choice = 1;
251 connect_host, connect_port = srv_choice.target or to_host, srv_choice.port or connect_port;
252 log("debug", "Best record found, will connect to %s:%d", connect_host, connect_port);
255 log("debug", to_host.." has no SRV records, falling back to A");
257 -- Try with SRV, or just the plain hostname if no SRV
258 local ok, err = try_connect(host_session, connect_host, connect_port);
260 if not attempt_connection(host_session, err) then
261 -- No more attempts will be made
262 destroy_session(host_session, err);
265 end, "_xmpp-server._tcp."..connect_host..".", "SRV");
267 return true; -- Attempt in progress
268 elseif host_session.srv_hosts and #host_session.srv_hosts > host_session.srv_choice then -- Not our first attempt, and we also have SRV
269 host_session.srv_choice = host_session.srv_choice + 1;
270 local srv_choice = host_session.srv_hosts[host_session.srv_choice];
271 connect_host, connect_port = srv_choice.target or to_host, srv_choice.port or connect_port;
272 host_session.log("info", "Connection failed (%s). Attempt #%d: This time to %s:%d", tostring(err), host_session.srv_choice, connect_host, connect_port);
274 host_session.log("info", "Out of connection options, can't connect to %s", tostring(host_session.to_host));
275 -- We're out of options
279 if not (connect_host and connect_port) then
280 -- Likely we couldn't resolve DNS
281 log("warn", "Hmm, we're without a host (%s) and port (%s) to connect to for %s, giving up :(", tostring(connect_host), tostring(connect_port), tostring(to_host));
285 return try_connect(host_session, connect_host, connect_port);
288 function try_connect(host_session, connect_host, connect_port)
289 host_session.connecting = true;
291 handle = adns.lookup(function (reply, err)
293 host_session.connecting = nil;
295 -- COMPAT: This is a compromise for all you CNAME-(ab)users :)
296 if not (reply and reply[#reply] and reply[#reply].a) then
297 local count = max_dns_depth;
298 reply = dns.peek(connect_host, "CNAME", "IN");
299 while count > 0 and reply and reply[#reply] and not reply[#reply].a and reply[#reply].cname do
300 log("debug", "Looking up %s (DNS depth is %d)", tostring(reply[#reply].cname), count);
301 reply = dns.peek(reply[#reply].cname, "A", "IN") or dns.peek(reply[#reply].cname, "CNAME", "IN");
305 -- end of CNAME resolving
307 if reply and reply[#reply] and reply[#reply].a then
308 log("debug", "DNS reply for %s gives us %s", connect_host, reply[#reply].a);
309 local ok, err = make_connect(host_session, reply[#reply].a, connect_port);
311 if not attempt_connection(host_session, err or "closed") then
312 err = err and (": "..err) or "";
313 destroy_session(host_session, "Connection failed"..err);
317 log("debug", "DNS lookup failed to get a response for %s", connect_host);
318 if not attempt_connection(host_session, "name resolution failed") then -- Retry if we can
319 log("debug", "No other records to try for %s - destroying", host_session.to_host);
320 err = err and (": "..err) or "";
321 destroy_session(host_session, "DNS resolution failed"..err); -- End of the line, we can't
324 end, connect_host, "A", "IN");
329 function make_connect(host_session, connect_host, connect_port)
330 (host_session.log or log)("info", "Beginning new connection attempt to %s (%s:%d)", host_session.to_host, connect_host, connect_port);
331 -- Ok, we're going to try to connect
333 local from_host, to_host = host_session.from_host, host_session.to_host;
335 local conn, handler = socket.tcp();
338 log("warn", "Failed to create outgoing connection, system error: %s", handler);
339 return false, handler;
343 local success, err = conn:connect(connect_host, connect_port);
344 if not success and err ~= "timeout" then
345 log("warn", "s2s connect() to %s (%s:%d) failed: %s", host_session.to_host, connect_host, connect_port, err);
349 local cl = connlisteners_get("xmppserver");
350 conn = wrapclient(conn, connect_host, connect_port, cl, cl.default_mode or 1 );
351 host_session.conn = conn;
353 local filter = initialize_filters(host_session);
354 local w, log = conn.write, host_session.log;
355 host_session.sends2s = function (t)
356 log("debug", "sending: %s", (t.top_tag and t:top_tag()) or t:match("^[^>]*>?"));
358 t = filter("stanzas/out", t);
361 t = filter("bytes/out", tostring(t));
363 return w(conn, tostring(t));
368 -- Register this outgoing connection so that xmppserver_listener knows about it
369 -- otherwise it will assume it is a new incoming connection
370 cl.register_outgoing(conn, host_session);
372 host_session:open_stream(from_host, to_host);
374 log("debug", "Connection attempt in progress...");
375 add_task(connect_timeout, function ()
376 if host_session.conn ~= conn or
377 host_session.type == "s2sout" or
378 host_session.connecting then
379 return; -- Ok, we're connect[ed|ing]
381 -- Not connected, need to close session and clean up
382 (host_session.log or log)("warn", "Destroying incomplete session %s->%s due to inactivity",
383 host_session.from_host or "(unknown)", host_session.to_host or "(unknown)");
384 host_session:close("connection-timeout");
389 function session_open_stream(session, from, to)
390 session.sends2s(st.stanza("stream:stream", {
391 xmlns='jabber:server', ["xmlns:db"]='jabber:server:dialback',
392 ["xmlns:stream"]='http://etherx.jabber.org/streams',
393 from=from, to=to, version='1.0', ["xml:lang"]='en'}):top_tag());
396 local function check_cert_status(session)
397 local conn = session.conn:socket()
399 if conn.getpeercertificate then
400 cert = conn:getpeercertificate()
404 local chain_valid, err = conn:getpeerchainvalid()
405 if not chain_valid then
406 session.cert_chain_status = "invalid";
407 (session.log or log)("debug", "certificate chain validation result: %s", err);
409 session.cert_chain_status = "valid";
411 local host = session.direction == "incoming" and session.from_host or session.to_host
413 -- We'll go ahead and verify the asserted identity if the
414 -- connecting server specified one.
416 if cert_verify_identity(host, "xmpp-server", cert) then
417 session.cert_identity_status = "valid"
419 session.cert_identity_status = "invalid"
426 function streamopened(session, attr)
427 local send = session.sends2s;
429 -- TODO: #29: SASL/TLS on s2s streams
430 session.version = tonumber(attr.version) or 0;
432 -- TODO: Rename session.secure to session.encrypted
433 if session.secure == false then
434 session.secure = true;
437 if session.direction == "incoming" then
438 -- Send a reply stream header
439 session.to_host = attr.to and nameprep(attr.to);
440 session.from_host = attr.from and nameprep(attr.from);
442 session.streamid = uuid_gen();
443 (session.log or log)("debug", "incoming s2s received <stream:stream>");
444 if session.to_host then
445 if not hosts[session.to_host] then
446 -- Attempting to connect to a host we don't serve
448 condition = "host-unknown";
449 text = "This host does not serve "..session.to_host
452 elseif hosts[session.to_host].disallow_s2s then
453 -- Attempting to connect to a host that disallows s2s
455 condition = "policy-violation";
456 text = "Server-to-server communication is not allowed to this host";
462 if session.secure and not session.cert_chain_status then check_cert_status(session); end
464 send("<?xml version='1.0'?>");
465 send(stanza("stream:stream", { xmlns='jabber:server', ["xmlns:db"]='jabber:server:dialback',
466 ["xmlns:stream"]='http://etherx.jabber.org/streams', id=session.streamid, from=session.to_host, to=session.from_host, version=(session.version > 0 and "1.0" or nil) }):top_tag());
467 if session.version >= 1.0 then
468 local features = st.stanza("stream:features");
470 if session.to_host then
471 hosts[session.to_host].events.fire_event("s2s-stream-features", { origin = session, features = features });
473 (session.log or log)("warn", "No 'to' on stream header from %s means we can't offer any features", session.from_host or "unknown host");
476 log("debug", "Sending stream features: %s", tostring(features));
479 elseif session.direction == "outgoing" then
480 -- If we are just using the connection for verifying dialback keys, we won't try and auth it
481 if not attr.id then error("stream response did not give us a streamid!!!"); end
482 session.streamid = attr.id;
484 if session.secure and not session.cert_chain_status then check_cert_status(session); end
486 -- Send unauthed buffer
487 -- (stanzas which are fine to send before dialback)
488 -- Note that this is *not* the stanza queue (which
489 -- we can only send if auth succeeds) :)
490 local send_buffer = session.send_buffer;
491 if send_buffer and #send_buffer > 0 then
492 log("debug", "Sending s2s send_buffer now...");
493 for i, data in ipairs(send_buffer) do
494 session.sends2s(tostring(data));
495 send_buffer[i] = nil;
498 session.send_buffer = nil;
500 -- If server is pre-1.0, don't wait for features, just do dialback
501 if session.version < 1.0 then
502 if not session.dialback_verifying then
503 log("debug", "Initiating dialback...");
504 initiate_dialback(session);
506 mark_connected(session);
510 session.notopen = nil;
513 function streamclosed(session)
514 (session.log or log)("debug", "Received </stream:stream>");
518 function initiate_dialback(session)
519 -- generate dialback key
520 session.dialback_key = generate_dialback(session.streamid, session.to_host, session.from_host);
521 session.sends2s(format("<db:result from='%s' to='%s'>%s</db:result>", session.from_host, session.to_host, session.dialback_key));
522 session.log("info", "sent dialback key on outgoing s2s stream");
525 function generate_dialback(id, to, from)
526 return sha256_hash(id..to..from..hosts[from].dialback_secret, true);
529 function verify_dialback(id, to, from, key)
530 return key == generate_dialback(id, to, from);
533 function make_authenticated(session, host)
534 if not session.secure then
535 local local_host = session.direction == "incoming" and session.to_host or session.from_host;
536 if config.get(local_host, "core", "s2s_require_encryption") then
538 condition = "policy-violation",
539 text = "Encrypted server-to-server communication is required but was not "
540 ..((session.direction == "outgoing" and "offered") or "used")
544 if session.type == "s2sout_unauthed" then
545 session.type = "s2sout";
546 elseif session.type == "s2sin_unauthed" then
547 session.type = "s2sin";
549 if not session.hosts[host] then session.hosts[host] = {}; end
550 session.hosts[host].authed = true;
552 elseif session.type == "s2sin" and host then
553 if not session.hosts[host] then session.hosts[host] = {}; end
554 session.hosts[host].authed = true;
558 session.log("debug", "connection %s->%s is now authenticated", session.from_host or "(unknown)", session.to_host or "(unknown)");
560 mark_connected(session);
565 -- Stream is authorised, and ready for normal stanzas
566 function mark_connected(session)
567 local sendq, send = session.sendq, session.sends2s;
569 local from, to = session.from_host, session.to_host;
571 session.log("info", session.direction.." s2s connection "..from.."->"..to.." complete");
573 local send_to_host = send_to_host;
574 function session.send(data) return send_to_host(to, from, data); end
576 local event_data = { session = session };
577 if session.type == "s2sout" then
578 prosody.events.fire_event("s2sout-established", event_data);
579 hosts[session.from_host].events.fire_event("s2sout-established", event_data);
581 prosody.events.fire_event("s2sin-established", event_data);
582 hosts[session.to_host].events.fire_event("s2sin-established", event_data);
585 if session.direction == "outgoing" then
587 session.log("debug", "sending "..#sendq.." queued stanzas across new outgoing connection to "..session.to_host);
588 for i, data in ipairs(sendq) do
595 session.srv_hosts = nil;
599 local resting_session = { -- Resting, not dead
601 type = "s2s_destroyed";
602 open_stream = function (session)
603 session.log("debug", "Attempt to open stream on resting session");
605 close = function (session)
606 session.log("debug", "Attempt to close already-closed session");
608 filter = function (type, data) return data; end;
609 }; resting_session.__index = resting_session;
611 function retire_session(session, reason)
612 local log = session.log or log;
613 for k in pairs(session) do
614 if k ~= "trace" and k ~= "log" and k ~= "id" then
619 session.destruction_reason = reason;
621 function session.send(data) log("debug", "Discarding data sent to resting session: %s", tostring(data)); end
622 function session.data(data) log("debug", "Discarding data received from resting session: %s", tostring(data)); end
623 return setmetatable(session, resting_session);
626 function destroy_session(session, reason)
627 if session.destroyed then return; end
628 (session.log or log)("info", "Destroying "..tostring(session.direction).." session "..tostring(session.from_host).."->"..tostring(session.to_host));
630 if session.direction == "outgoing" then
631 hosts[session.from_host].s2sout[session.to_host] = nil;
632 bounce_sendq(session, reason);
633 elseif session.direction == "incoming" then
634 incoming_s2s[session] = nil;
637 local event_data = { session = session, reason = reason };
638 if session.type == "s2sout" then
639 prosody.events.fire_event("s2sout-destroyed", event_data);
640 if hosts[session.from_host] then
641 hosts[session.from_host].events.fire_event("s2sout-destroyed", event_data);
643 elseif session.type == "s2sin" then
644 prosody.events.fire_event("s2sin-destroyed", event_data);
645 if hosts[session.to_host] then
646 hosts[session.to_host].events.fire_event("s2sin-destroyed", event_data);
650 retire_session(session, reason); -- Clean session until it is GC'd