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.
9 --- Module containing all the logic for connecting to a remote server
11 local portmanager = require "core.portmanager";
12 local wrapclient = require "net.server".wrapclient;
13 local initialize_filters = require "util.filters".initialize;
14 local idna_to_ascii = require "util.encodings".idna.to_ascii;
15 local new_ip = require "util.ip".new_ip;
16 local rfc3484_dest = require "util.rfc3484".destination;
17 local socket = require "socket";
18 local adns = require "net.adns";
19 local dns = require "net.dns";
20 local t_insert, t_sort, ipairs = table.insert, table.sort, ipairs;
21 local st = require "util.stanza";
23 local s2s_destroy_session = require "core.s2smanager".destroy_session;
25 local log = module._log;
28 local has_ipv4, has_ipv6;
30 local dns_timeout = module:get_option_number("dns_timeout", 15);
31 dns.settimeout(dns_timeout);
32 local max_dns_depth = module:get_option_number("dns_max_depth", 3);
39 function s2sout.set_listener(listener)
40 s2s_listener = listener;
43 local function compare_srv_priorities(a,b)
44 return a.priority < b.priority or (a.priority == b.priority and a.weight > b.weight);
47 local function session_open_stream(session, from, to)
48 session.sends2s(st.stanza("stream:stream", {
49 xmlns='jabber:server', ["xmlns:db"]='jabber:server:dialback',
50 ["xmlns:stream"]='http://etherx.jabber.org/streams',
51 from=from, to=to, version='1.0', ["xml:lang"]='en'}):top_tag());
54 function s2sout.initiate_connection(host_session)
55 initialize_filters(host_session);
56 host_session.open_stream = session_open_stream;
58 -- Kick the connection attempting machine into life
59 if not s2sout.attempt_connection(host_session) then
60 -- Intentionally not returning here, the
61 -- session is needed, connected or not
62 s2s_destroy_session(host_session);
65 if not host_session.sends2s then
66 -- A sends2s which buffers data (until the stream is opened)
67 -- note that data in this buffer will be sent before the stream is authed
68 -- and will not be ack'd in any way, successful or otherwise
70 function host_session.sends2s(data)
73 host_session.send_buffer = buffer;
75 log("debug", "Buffering data on unconnected s2sout to %s", tostring(host_session.to_host));
76 buffer[#buffer+1] = data;
77 log("debug", "Buffered item %d: %s", #buffer, tostring(data));
82 function s2sout.attempt_connection(host_session, err)
83 local from_host, to_host = host_session.from_host, host_session.to_host;
84 local connect_host, connect_port = to_host and idna_to_ascii(to_host), 5269;
86 if not connect_host then
90 if not err then -- This is our first attempt
91 log("debug", "First attempt to connect to %s, starting with SRV lookup...", to_host);
92 host_session.connecting = true;
94 handle = adns.lookup(function (answer)
96 host_session.connecting = nil;
98 log("debug", to_host.." has SRV records, handling...");
100 host_session.srv_hosts = srv_hosts;
101 for _, record in ipairs(answer) do
102 t_insert(srv_hosts, record.srv);
104 if #srv_hosts == 1 and srv_hosts[1].target == "." then
105 log("debug", to_host.." does not provide a XMPP service");
106 s2s_destroy_session(host_session, err); -- Nothing to see here
109 t_sort(srv_hosts, compare_srv_priorities);
111 local srv_choice = srv_hosts[1];
112 host_session.srv_choice = 1;
114 connect_host, connect_port = srv_choice.target or to_host, srv_choice.port or connect_port;
115 log("debug", "Best record found, will connect to %s:%d", connect_host, connect_port);
118 log("debug", to_host.." has no SRV records, falling back to A/AAAA");
120 -- Try with SRV, or just the plain hostname if no SRV
121 local ok, err = s2sout.try_connect(host_session, connect_host, connect_port);
123 if not s2sout.attempt_connection(host_session, err) then
124 -- No more attempts will be made
125 s2s_destroy_session(host_session, err);
128 end, "_xmpp-server._tcp."..connect_host..".", "SRV");
130 return true; -- Attempt in progress
131 elseif host_session.ip_hosts then
132 return s2sout.try_connect(host_session, connect_host, connect_port, err);
133 elseif host_session.srv_hosts and #host_session.srv_hosts > host_session.srv_choice then -- Not our first attempt, and we also have SRV
134 host_session.srv_choice = host_session.srv_choice + 1;
135 local srv_choice = host_session.srv_hosts[host_session.srv_choice];
136 connect_host, connect_port = srv_choice.target or to_host, srv_choice.port or connect_port;
137 host_session.log("info", "Connection failed (%s). Attempt #%d: This time to %s:%d", tostring(err), host_session.srv_choice, connect_host, connect_port);
139 host_session.log("info", "Out of connection options, can't connect to %s", tostring(host_session.to_host));
140 -- We're out of options
144 if not (connect_host and connect_port) then
145 -- Likely we couldn't resolve DNS
146 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));
150 return s2sout.try_connect(host_session, connect_host, connect_port);
153 function s2sout.try_next_ip(host_session)
154 host_session.connecting = nil;
155 host_session.ip_choice = host_session.ip_choice + 1;
156 local ip = host_session.ip_hosts[host_session.ip_choice];
157 local ok, err= s2sout.make_connect(host_session, ip.ip, ip.port);
159 if not s2sout.attempt_connection(host_session, err or "closed") then
160 err = err and (": "..err) or "";
161 s2s_destroy_session(host_session, "Connection failed"..err);
166 function s2sout.try_connect(host_session, connect_host, connect_port, err)
167 host_session.connecting = true;
171 host_session.ip_hosts = IPs;
172 local handle4, handle6;
173 local has_other = false;
176 handle4 = adns.lookup(function (reply, err)
179 -- COMPAT: This is a compromise for all you CNAME-(ab)users :)
180 if not (reply and reply[#reply] and reply[#reply].a) then
181 local count = max_dns_depth;
182 reply = dns.peek(connect_host, "CNAME", "IN");
183 while count > 0 and reply and reply[#reply] and not reply[#reply].a and reply[#reply].cname do
184 log("debug", "Looking up %s (DNS depth is %d)", tostring(reply[#reply].cname), count);
185 reply = dns.peek(reply[#reply].cname, "A", "IN") or dns.peek(reply[#reply].cname, "CNAME", "IN");
189 -- end of CNAME resolving
191 if reply and reply[#reply] and reply[#reply].a then
192 for _, ip in ipairs(reply) do
193 log("debug", "DNS reply for %s gives us %s", connect_host, ip.a);
194 IPs[#IPs+1] = new_ip(ip.a, "IPv4");
200 rfc3484_dest(host_session.ip_hosts, sources);
202 IPs[i] = {ip = IPs[i], port = connect_port};
204 host_session.ip_choice = 0;
205 s2sout.try_next_ip(host_session);
207 log("debug", "DNS lookup failed to get a response for %s", connect_host);
208 host_session.ip_hosts = nil;
209 if not s2sout.attempt_connection(host_session, "name resolution failed") then -- Retry if we can
210 log("debug", "No other records to try for %s - destroying", host_session.to_host);
211 err = err and (": "..err) or "";
212 s2s_destroy_session(host_session, "DNS resolution failed"..err); -- End of the line, we can't
218 end, connect_host, "A", "IN");
224 handle6 = adns.lookup(function (reply, err)
227 if reply and reply[#reply] and reply[#reply].aaaa then
228 for _, ip in ipairs(reply) do
229 log("debug", "DNS reply for %s gives us %s", connect_host, ip.aaaa);
230 IPs[#IPs+1] = new_ip(ip.aaaa, "IPv6");
236 rfc3484_dest(host_session.ip_hosts, sources);
238 IPs[i] = {ip = IPs[i], port = connect_port};
240 host_session.ip_choice = 0;
241 s2sout.try_next_ip(host_session);
243 log("debug", "DNS lookup failed to get a response for %s", connect_host);
244 host_session.ip_hosts = nil;
245 if not s2sout.attempt_connection(host_session, "name resolution failed") then -- Retry if we can
246 log("debug", "No other records to try for %s - destroying", host_session.to_host);
247 err = err and (": "..err) or "";
248 s2s_destroy_session(host_session, "DNS resolution failed"..err); -- End of the line, we can't
254 end, connect_host, "AAAA", "IN");
260 elseif host_session.ip_hosts and #host_session.ip_hosts > host_session.ip_choice then -- Not our first attempt, and we also have IPs left to try
261 s2sout.try_next_ip(host_session);
263 host_session.ip_hosts = nil;
264 if not s2sout.attempt_connection(host_session, "out of IP addresses") then -- Retry if we can
265 log("debug", "No other records to try for %s - destroying", host_session.to_host);
266 err = err and (": "..err) or "";
267 s2s_destroy_session(host_session, "Connecting failed"..err); -- End of the line, we can't
275 function s2sout.make_connect(host_session, connect_host, connect_port)
276 (host_session.log or log)("info", "Beginning new connection attempt to %s ([%s]:%d)", host_session.to_host, connect_host.addr, connect_port);
277 -- Ok, we're going to try to connect
279 local from_host, to_host = host_session.from_host, host_session.to_host;
282 if connect_host.proto == "IPv4" then
283 conn, handler = socket.tcp();
285 conn, handler = socket.tcp6();
289 log("warn", "Failed to create outgoing connection, system error: %s", handler);
290 return false, handler;
294 local success, err = conn:connect(connect_host.addr, connect_port);
295 if not success and err ~= "timeout" then
296 log("warn", "s2s connect() to %s (%s:%d) failed: %s", host_session.to_host, connect_host.addr, connect_port, err);
300 conn = wrapclient(conn, connect_host.addr, connect_port, s2s_listener, "*a");
301 host_session.conn = conn;
303 local filter = initialize_filters(host_session);
304 local w, log = conn.write, host_session.log;
305 host_session.sends2s = function (t)
306 log("debug", "sending: %s", (t.top_tag and t:top_tag()) or t:match("^[^>]*>?"));
308 t = filter("stanzas/out", t);
311 t = filter("bytes/out", tostring(t));
313 return w(conn, tostring(t));
318 -- Register this outgoing connection so that xmppserver_listener knows about it
319 -- otherwise it will assume it is a new incoming connection
320 s2s_listener.register_outgoing(conn, host_session);
322 log("debug", "Connection attempt in progress...");
326 module:hook_global("service-added", function (event)
327 if event.name ~= "s2s" then return end
329 local s2s_sources = portmanager.get_active_services():get("s2s");
330 if not s2s_sources then
331 module:log("warn", "s2s not listening on any ports, outgoing connections may fail");
334 for source, _ in pairs(s2s_sources) do
335 if source == "*" or source == "0.0.0.0" then
336 if not socket.local_addresses then
337 sources[#sources + 1] = new_ip("0.0.0.0", "IPv4");
339 for _, addr in ipairs(socket.local_addresses("ipv4", true)) do
340 sources[#sources + 1] = new_ip(addr, "IPv4");
343 elseif source == "::" then
344 if not socket.local_addresses then
345 sources[#sources + 1] = new_ip("::", "IPv6");
347 for _, addr in ipairs(socket.local_addresses("ipv6", true)) do
348 sources[#sources + 1] = new_ip(addr, "IPv6");
352 sources[#sources + 1] = new_ip(source, (source:find(":") and "IPv6") or "IPv4");
355 for i = 1,#sources do
356 if sources[i].proto == "IPv6" then
358 elseif sources[i].proto == "IPv4" then