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,
21 = tostring, pairs, ipairs, getmetatable, newproxy, error, tonumber,
24 local idna_to_ascii = require "util.encodings".idna.to_ascii;
25 local connlisteners_get = require "net.connlisteners".get;
26 local wrapclient = require "net.server".wrapclient;
27 local modulemanager = require "core.modulemanager";
28 local st = require "stanza";
29 local stanza = st.stanza;
30 local nameprep = require "util.encodings".stringprep.nameprep;
32 local fire_event = require "core.eventmanager".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 60;
45 local max_dns_depth = config.get("*", "core", "dns_max_depth") or 3;
48 _G.prosody.incoming_s2s = incoming_s2s;
49 local incoming_s2s = incoming_s2s;
53 function compare_srv_priorities(a,b)
54 return a.priority < b.priority or (a.priority == b.priority and a.weight > b.weight);
57 local function bounce_sendq(session, reason)
58 local sendq = session.sendq;
60 session.log("info", "sending error replies for "..#sendq.." queued stanzas because of failed outgoing connection to "..tostring(session.to_host));
64 (session.log or log)("error", "Replying to to an s2s error reply, please report this! Traceback: %s", get_traceback());
68 for i, data in ipairs(sendq) do
69 local reply = data[2];
70 local xmlns = reply.attr.xmlns;
72 reply.attr.type = "error";
73 reply:tag("error", {type = "cancel"})
74 :tag("remote-server-not-found", {xmlns = "urn:ietf:params:xml:ns:xmpp-stanzas"}):up();
76 reply:tag("text", {xmlns = "urn:ietf:params:xml:ns:xmpp-stanzas"}):text("Connection failed: "..reason):up();
78 core_process_stanza(dummy, reply);
86 function send_to_host(from_host, to_host, data)
87 if not hosts[from_host] then
88 log("warn", "Attempt to send stanza from %s - a host we don't serve", from_host);
91 local host = hosts[from_host].s2sout[to_host];
93 -- We have a connection to this host already
94 if host.type == "s2sout_unauthed" and (data.name ~= "db:verify" or not host.dialback_key) then
95 (host.log or log)("debug", "trying to send over unauthed s2sout to "..to_host);
97 -- Queue stanza until we are able to send it
98 if host.sendq then t_insert(host.sendq, {tostring(data), st.reply(data)});
99 else host.sendq = { {tostring(data), st.reply(data)} }; end
100 host.log("debug", "stanza [%s] queued ", data.name);
101 elseif host.type == "local" or host.type == "component" then
102 log("error", "Trying to send a stanza to ourselves??")
103 log("error", "Traceback: %s", get_traceback());
104 log("error", "Stanza: %s", tostring(data));
106 (host.log or log)("debug", "going to send stanza to "..to_host.." from "..from_host);
108 if host.from_host ~= from_host then
109 log("error", "WARNING! This might, possibly, be a bug, but it might not...");
110 log("error", "We are going to send from %s instead of %s", tostring(host.from_host), tostring(from_host));
113 host.log("debug", "stanza sent over "..host.type);
116 log("debug", "opening a new outgoing connection for this stanza");
117 local host_session = new_outgoing(from_host, to_host);
120 host_session.sendq = { {tostring(data), st.reply(data)} };
121 log("debug", "stanza [%s] queued until connection complete", tostring(data.name));
122 if (not host_session.connecting) and (not host_session.conn) then
123 log("warn", "Connection to %s failed already, destroying session...", to_host);
124 destroy_session(host_session);
129 local open_sessions = 0;
131 function new_incoming(conn)
132 local session = { conn = conn, type = "s2sin_unauthed", direction = "incoming", hosts = {} };
134 session.trace = newproxy(true);
135 getmetatable(session.trace).__gc = function () open_sessions = open_sessions - 1; end;
137 open_sessions = open_sessions + 1;
138 local w, log = conn.write, logger_init("s2sin"..tostring(conn):match("[a-f0-9]+$"));
140 session.sends2s = function (t) log("debug", "sending: %s", t.top_tag and t:top_tag() or t:match("^([^>]*>?)")); w(conn, tostring(t)); end
141 incoming_s2s[session] = true;
142 add_task(connect_timeout, function ()
143 if session.conn ~= conn or
144 session.type == "s2sin" then
145 return; -- Ok, we're connect[ed|ing]
147 -- Not connected, need to close session and clean up
148 (session.log or log)("warn", "Destroying incomplete session %s->%s due to inactivity",
149 session.from_host or "(unknown)", session.to_host or "(unknown)");
150 session:close("connection-timeout");
155 function new_outgoing(from_host, to_host, connect)
156 local host_session = { to_host = to_host, from_host = from_host, host = from_host,
157 notopen = true, type = "s2sout_unauthed", direction = "outgoing",
158 open_stream = session_open_stream };
160 hosts[from_host].s2sout[to_host] = host_session;
164 local conn_name = "s2sout"..tostring(host_session):match("[a-f0-9]*$");
165 log = logger_init(conn_name);
166 host_session.log = log;
169 if connect ~= false then
170 -- Kick the connection attempting machine into life
171 attempt_connection(host_session);
174 if not host_session.sends2s then
175 -- A sends2s which buffers data (until the stream is opened)
176 -- note that data in this buffer will be sent before the stream is authed
177 -- and will not be ack'd in any way, successful or otherwise
179 function host_session.sends2s(data)
182 host_session.send_buffer = buffer;
184 log("debug", "Buffering data on unconnected s2sout to %s", to_host);
185 buffer[#buffer+1] = data;
186 log("debug", "Buffered item %d: %s", #buffer, tostring(data));
194 function attempt_connection(host_session, err)
195 local from_host, to_host = host_session.from_host, host_session.to_host;
196 local connect_host, connect_port = to_host and idna_to_ascii(to_host), 5269;
198 if not connect_host then
202 if not err then -- This is our first attempt
203 log("debug", "First attempt to connect to %s, starting with SRV lookup...", to_host);
204 host_session.connecting = true;
206 handle = adns.lookup(function (answer)
208 host_session.connecting = nil;
210 log("debug", to_host.." has SRV records, handling...");
211 local srv_hosts = {};
212 host_session.srv_hosts = srv_hosts;
213 for _, record in ipairs(answer) do
214 t_insert(srv_hosts, record.srv);
216 t_sort(srv_hosts, compare_srv_priorities);
218 local srv_choice = srv_hosts[1];
219 host_session.srv_choice = 1;
221 connect_host, connect_port = srv_choice.target or to_host, srv_choice.port or connect_port;
222 log("debug", "Best record found, will connect to %s:%d", connect_host, connect_port);
225 log("debug", to_host.." has no SRV records, falling back to A");
227 -- Try with SRV, or just the plain hostname if no SRV
228 local ok, err = try_connect(host_session, connect_host, connect_port);
230 if not attempt_connection(host_session, err) then
231 -- No more attempts will be made
232 destroy_session(host_session, err);
235 end, "_xmpp-server._tcp."..connect_host..".", "SRV");
237 -- Set handler for DNS timeout
238 add_task(dns_timeout, function ()
240 adns.cancel(handle, true);
244 return true; -- Attempt in progress
245 elseif host_session.srv_hosts and #host_session.srv_hosts > host_session.srv_choice then -- Not our first attempt, and we also have SRV
246 host_session.srv_choice = host_session.srv_choice + 1;
247 local srv_choice = host_session.srv_hosts[host_session.srv_choice];
248 connect_host, connect_port = srv_choice.target or to_host, srv_choice.port or connect_port;
249 host_session.log("info", "Connection failed (%s). Attempt #%d: This time to %s:%d", tostring(err), host_session.srv_choice, connect_host, connect_port);
251 host_session.log("info", "Out of connection options, can't connect to %s", tostring(host_session.to_host));
252 -- We're out of options
256 if not (connect_host and connect_port) then
257 -- Likely we couldn't resolve DNS
258 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));
262 return try_connect(host_session, connect_host, connect_port);
265 function try_connect(host_session, connect_host, connect_port)
266 host_session.connecting = true;
268 handle = adns.lookup(function (reply)
270 host_session.connecting = nil;
272 -- COMPAT: This is a compromise for all you CNAME-(ab)users :)
273 if not (reply and reply[#reply] and reply[#reply].a) then
274 local count = max_dns_depth;
275 reply = dns.peek(connect_host, "CNAME", "IN");
276 while count > 0 and reply and reply[#reply] and not reply[#reply].a and reply[#reply].cname do
277 log("debug", "Looking up %s (DNS depth is %d)", tostring(reply[#reply].cname), count);
278 reply = dns.peek(reply[#reply].cname, "A", "IN") or dns.peek(reply[#reply].cname, "CNAME", "IN");
282 -- end of CNAME resolving
284 if reply and reply[#reply] and reply[#reply].a then
285 log("debug", "DNS reply for %s gives us %s", connect_host, reply[#reply].a);
286 return make_connect(host_session, reply[#reply].a, connect_port);
288 log("debug", "DNS lookup failed to get a response for %s", connect_host);
289 if not attempt_connection(host_session, "name resolution failed") then -- Retry if we can
290 log("debug", "No other records to try for %s - destroying", host_session.to_host);
291 destroy_session(host_session, "DNS resolution failed"); -- End of the line, we can't
294 end, connect_host, "A", "IN");
296 -- Set handler for DNS timeout
297 add_task(dns_timeout, function ()
299 adns.cancel(handle, true);
306 function make_connect(host_session, connect_host, connect_port)
307 (host_session.log or log)("info", "Beginning new connection attempt to %s (%s:%d)", host_session.to_host, connect_host, connect_port);
308 -- Ok, we're going to try to connect
310 local from_host, to_host = host_session.from_host, host_session.to_host;
312 local conn, handler = socket.tcp()
315 log("warn", "Failed to create outgoing connection, system error: %s", handler);
316 return false, handler;
320 local success, err = conn:connect(connect_host, connect_port);
321 if not success and err ~= "timeout" then
322 log("warn", "s2s connect() to %s (%s:%d) failed: %s", host_session.to_host, connect_host, connect_port, err);
326 local cl = connlisteners_get("xmppserver");
327 conn = wrapclient(conn, connect_host, connect_port, cl, cl.default_mode or 1 );
328 host_session.conn = conn;
330 -- Register this outgoing connection so that xmppserver_listener knows about it
331 -- otherwise it will assume it is a new incoming connection
332 cl.register_outgoing(conn, host_session);
334 local w, log = conn.write, host_session.log;
335 host_session.sends2s = function (t) log("debug", "sending: %s", (t.top_tag and t:top_tag()) or t:match("^[^>]*>?")); w(conn, tostring(t)); end
337 host_session:open_stream(from_host, to_host);
339 log("debug", "Connection attempt in progress...");
340 add_task(connect_timeout, function ()
341 if host_session.conn ~= conn or
342 host_session.type == "s2sout" or
343 host_session.connecting then
344 return; -- Ok, we're connect[ed|ing]
346 -- Not connected, need to close session and clean up
347 (host_session.log or log)("warn", "Destroying incomplete session %s->%s due to inactivity",
348 host_session.from_host or "(unknown)", host_session.to_host or "(unknown)");
349 host_session:close("connection-timeout");
354 function session_open_stream(session, from, to)
355 session.sends2s(st.stanza("stream:stream", {
356 xmlns='jabber:server', ["xmlns:db"]='jabber:server:dialback',
357 ["xmlns:stream"]='http://etherx.jabber.org/streams',
358 from=from, to=to, version='1.0', ["xml:lang"]='en'}):top_tag());
361 function streamopened(session, attr)
362 local send = session.sends2s;
364 -- TODO: #29: SASL/TLS on s2s streams
365 session.version = tonumber(attr.version) or 0;
367 if session.secure == false then
368 session.secure = true;
371 if session.direction == "incoming" then
372 -- Send a reply stream header
373 session.to_host = attr.to and nameprep(attr.to);
374 session.from_host = attr.from and nameprep(attr.from);
376 session.streamid = uuid_gen();
377 (session.log or log)("debug", "incoming s2s received <stream:stream>");
378 if session.to_host and not hosts[session.to_host] then
379 -- Attempting to connect to a host we don't serve
380 session:close({ condition = "host-unknown"; text = "This host does not serve "..session.to_host });
383 send("<?xml version='1.0'?>");
384 send(stanza("stream:stream", { xmlns='jabber:server', ["xmlns:db"]='jabber:server:dialback',
385 ["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());
386 if session.version >= 1.0 then
387 local features = st.stanza("stream:features");
389 if session.to_host then
390 hosts[session.to_host].events.fire_event("s2s-stream-features", { origin = session, features = features });
392 (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");
395 log("debug", "Sending stream features: %s", tostring(features));
398 elseif session.direction == "outgoing" then
399 -- If we are just using the connection for verifying dialback keys, we won't try and auth it
400 if not attr.id then error("stream response did not give us a streamid!!!"); end
401 session.streamid = attr.id;
403 -- Send unauthed buffer
404 -- (stanzas which are fine to send before dialback)
405 -- Note that this is *not* the stanza queue (which
406 -- we can only send if auth succeeds) :)
407 local send_buffer = session.send_buffer;
408 if send_buffer and #send_buffer > 0 then
409 log("debug", "Sending s2s send_buffer now...");
410 for i, data in ipairs(send_buffer) do
411 session.sends2s(tostring(data));
412 send_buffer[i] = nil;
415 session.send_buffer = nil;
417 -- If server is pre-1.0, don't wait for features, just do dialback
418 if session.version < 1.0 then
419 if not session.dialback_verifying then
420 log("debug", "Initiating dialback...");
421 initiate_dialback(session);
423 mark_connected(session);
427 session.notopen = nil;
430 function streamclosed(session)
431 (session.log or log)("debug", "Received </stream:stream>");
435 function initiate_dialback(session)
436 -- generate dialback key
437 session.dialback_key = generate_dialback(session.streamid, session.to_host, session.from_host);
438 session.sends2s(format("<db:result from='%s' to='%s'>%s</db:result>", session.from_host, session.to_host, session.dialback_key));
439 session.log("info", "sent dialback key on outgoing s2s stream");
442 function generate_dialback(id, to, from)
443 return sha256_hash(id..to..from..hosts[from].dialback_secret, true);
446 function verify_dialback(id, to, from, key)
447 return key == generate_dialback(id, to, from);
450 function make_authenticated(session, host)
451 if not session.secure then
452 local local_host = session.direction == "incoming" and session.to_host or session.from_host;
453 if config.get(local_host, "core", "s2s_require_encryption") then
455 condition = "policy-violation",
456 text = "Encrypted server-to-server communication is required but was not "
457 ..((session.direction == "outgoing" and "offered") or "used")
461 if session.type == "s2sout_unauthed" then
462 session.type = "s2sout";
463 elseif session.type == "s2sin_unauthed" then
464 session.type = "s2sin";
466 session.hosts[host].authed = true;
468 elseif session.type == "s2sin" and host then
469 session.hosts[host].authed = true;
473 session.log("debug", "connection %s->%s is now authenticated", session.from_host or "(unknown)", session.to_host or "(unknown)");
475 mark_connected(session);
480 -- Stream is authorised, and ready for normal stanzas
481 function mark_connected(session)
482 local sendq, send = session.sendq, session.sends2s;
484 local from, to = session.from_host, session.to_host;
486 session.log("info", session.direction.." s2s connection "..from.."->"..to.." complete");
488 local send_to_host = send_to_host;
489 function session.send(data) send_to_host(to, from, data); end
492 if session.direction == "outgoing" then
494 session.log("debug", "sending "..#sendq.." queued stanzas across new outgoing connection to "..session.to_host);
495 for i, data in ipairs(sendq) do
502 session.srv_hosts = nil;
506 local resting_session = { -- Resting, not dead
508 type = "s2s_destroyed";
509 open_stream = function (session)
510 session.log("debug", "Attempt to open stream on resting session");
512 close = function (session)
513 session.log("debug", "Attempt to close already-closed session");
515 }; resting_session.__index = resting_session;
517 function retire_session(session)
518 local log = session.log or log;
519 for k in pairs(session) do
520 if k ~= "trace" and k ~= "log" and k ~= "id" then
525 function session.send(data) log("debug", "Discarding data sent to resting session: %s", tostring(data)); end
526 function session.data(data) log("debug", "Discarding data received from resting session: %s", tostring(data)); end
527 return setmetatable(session, resting_session);
530 function destroy_session(session, reason)
531 if session.destroyed then return; end
532 (session.log or log)("info", "Destroying "..tostring(session.direction).." session "..tostring(session.from_host).."->"..tostring(session.to_host));
534 if session.direction == "outgoing" then
535 hosts[session.from_host].s2sout[session.to_host] = nil;
536 bounce_sendq(session, reason);
537 elseif session.direction == "incoming" then
538 incoming_s2s[session] = nil;
541 retire_session(session); -- Clean session until it is GC'd