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 rfc6724_dest = require "util.rfc6724".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 local_addresses = require "util.net".local_addresses;
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 function s2sout.initiate_connection(host_session)
48 initialize_filters(host_session);
49 host_session.version = 1;
51 -- Kick the connection attempting machine into life
52 if not s2sout.attempt_connection(host_session) then
53 -- Intentionally not returning here, the
54 -- session is needed, connected or not
55 s2s_destroy_session(host_session);
58 if not host_session.sends2s then
59 -- A sends2s which buffers data (until the stream is opened)
60 -- note that data in this buffer will be sent before the stream is authed
61 -- and will not be ack'd in any way, successful or otherwise
63 function host_session.sends2s(data)
66 host_session.send_buffer = buffer;
68 log("debug", "Buffering data on unconnected s2sout to %s", tostring(host_session.to_host));
69 buffer[#buffer+1] = data;
70 log("debug", "Buffered item %d: %s", #buffer, tostring(data));
75 function s2sout.attempt_connection(host_session, err)
76 local to_host = host_session.to_host;
77 local connect_host, connect_port = to_host and idna_to_ascii(to_host), 5269;
79 if not connect_host then
83 if not err then -- This is our first attempt
84 log("debug", "First attempt to connect to %s, starting with SRV lookup...", to_host);
85 host_session.connecting = true;
87 handle = adns.lookup(function (answer)
89 host_session.connecting = nil;
90 if answer and #answer > 0 then
91 log("debug", "%s has SRV records, handling...", to_host);
92 local srv_hosts = { answer = answer };
93 host_session.srv_hosts = srv_hosts;
94 for _, record in ipairs(answer) do
95 t_insert(srv_hosts, record.srv);
97 if #srv_hosts == 1 and srv_hosts[1].target == "." then
98 log("debug", "%s does not provide a XMPP service", to_host);
99 s2s_destroy_session(host_session, err); -- Nothing to see here
102 t_sort(srv_hosts, compare_srv_priorities);
104 local srv_choice = srv_hosts[1];
105 host_session.srv_choice = 1;
107 connect_host, connect_port = srv_choice.target or to_host, srv_choice.port or connect_port;
108 log("debug", "Best record found, will connect to %s:%d", connect_host, connect_port);
111 log("debug", "%s has no SRV records, falling back to A/AAAA", to_host);
113 -- Try with SRV, or just the plain hostname if no SRV
114 local ok, err = s2sout.try_connect(host_session, connect_host, connect_port);
116 if not s2sout.attempt_connection(host_session, err) then
117 -- No more attempts will be made
118 s2s_destroy_session(host_session, err);
121 end, "_xmpp-server._tcp."..connect_host..".", "SRV");
123 return true; -- Attempt in progress
124 elseif host_session.ip_hosts then
125 return s2sout.try_connect(host_session, connect_host, connect_port, err);
126 elseif host_session.srv_hosts and #host_session.srv_hosts > host_session.srv_choice then -- Not our first attempt, and we also have SRV
127 host_session.srv_choice = host_session.srv_choice + 1;
128 local srv_choice = host_session.srv_hosts[host_session.srv_choice];
129 connect_host, connect_port = srv_choice.target or to_host, srv_choice.port or connect_port;
130 host_session.log("info", "Connection failed (%s). Attempt #%d: This time to %s:%d", tostring(err), host_session.srv_choice, connect_host, connect_port);
132 host_session.log("info", "Failed in all attempts to connect to %s", tostring(host_session.to_host));
133 -- We're out of options
137 if not (connect_host and connect_port) then
138 -- Likely we couldn't resolve DNS
139 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));
143 return s2sout.try_connect(host_session, connect_host, connect_port);
146 function s2sout.try_next_ip(host_session)
147 host_session.connecting = nil;
148 host_session.ip_choice = host_session.ip_choice + 1;
149 local ip = host_session.ip_hosts[host_session.ip_choice];
150 local ok, err= s2sout.make_connect(host_session, ip.ip, ip.port);
152 if not s2sout.attempt_connection(host_session, err or "closed") then
153 err = err and (": "..err) or "";
154 s2s_destroy_session(host_session, "Connection failed"..err);
159 function s2sout.try_connect(host_session, connect_host, connect_port, err)
160 host_session.connecting = true;
164 host_session.ip_hosts = IPs;
165 local handle4, handle6;
166 local have_other_result = not(has_ipv4) or not(has_ipv6) or false;
169 handle4 = adns.lookup(function (reply, err)
172 -- COMPAT: This is a compromise for all you CNAME-(ab)users :)
173 if not (reply and reply[#reply] and reply[#reply].a) then
174 local count = max_dns_depth;
175 reply = dns.peek(connect_host, "CNAME", "IN");
176 while count > 0 and reply and reply[#reply] and not reply[#reply].a and reply[#reply].cname do
177 log("debug", "Looking up %s (DNS depth is %d)", tostring(reply[#reply].cname), count);
178 reply = dns.peek(reply[#reply].cname, "A", "IN") or dns.peek(reply[#reply].cname, "CNAME", "IN");
182 -- end of CNAME resolving
184 if reply and reply[#reply] and reply[#reply].a then
185 for _, ip in ipairs(reply) do
186 log("debug", "DNS reply for %s gives us %s", connect_host, ip.a);
187 IPs[#IPs+1] = new_ip(ip.a, "IPv4");
191 if have_other_result then
193 rfc6724_dest(host_session.ip_hosts, sources);
195 IPs[i] = {ip = IPs[i], port = connect_port};
197 host_session.ip_choice = 0;
198 s2sout.try_next_ip(host_session);
200 log("debug", "DNS lookup failed to get a response for %s", connect_host);
201 host_session.ip_hosts = nil;
202 if not s2sout.attempt_connection(host_session, "name resolution failed") then -- Retry if we can
203 log("debug", "No other records to try for %s - destroying", host_session.to_host);
204 err = err and (": "..err) or "";
205 s2s_destroy_session(host_session, "DNS resolution failed"..err); -- End of the line, we can't
209 have_other_result = true;
211 end, connect_host, "A", "IN");
213 have_other_result = true;
217 handle6 = adns.lookup(function (reply, err)
220 if reply and reply[#reply] and reply[#reply].aaaa then
221 for _, ip in ipairs(reply) do
222 log("debug", "DNS reply for %s gives us %s", connect_host, ip.aaaa);
223 IPs[#IPs+1] = new_ip(ip.aaaa, "IPv6");
227 if have_other_result then
229 rfc6724_dest(host_session.ip_hosts, sources);
231 IPs[i] = {ip = IPs[i], port = connect_port};
233 host_session.ip_choice = 0;
234 s2sout.try_next_ip(host_session);
236 log("debug", "DNS lookup failed to get a response for %s", connect_host);
237 host_session.ip_hosts = nil;
238 if not s2sout.attempt_connection(host_session, "name resolution failed") then -- Retry if we can
239 log("debug", "No other records to try for %s - destroying", host_session.to_host);
240 err = err and (": "..err) or "";
241 s2s_destroy_session(host_session, "DNS resolution failed"..err); -- End of the line, we can't
245 have_other_result = true;
247 end, connect_host, "AAAA", "IN");
249 have_other_result = true;
252 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
253 s2sout.try_next_ip(host_session);
255 host_session.ip_hosts = nil;
256 if not s2sout.attempt_connection(host_session, "out of IP addresses") then -- Retry if we can
257 log("debug", "No other records to try for %s - destroying", host_session.to_host);
258 err = err and (": "..err) or "";
259 s2s_destroy_session(host_session, "Connecting failed"..err); -- End of the line, we can't
267 function s2sout.make_connect(host_session, connect_host, connect_port)
268 (host_session.log or log)("debug", "Beginning new connection attempt to %s ([%s]:%d)", host_session.to_host, connect_host.addr, connect_port);
270 -- Reset secure flag in case this is another
271 -- connection attempt after a failed STARTTLS
272 host_session.secure = nil;
275 local proto = connect_host.proto;
276 if proto == "IPv4" then
277 conn, handler = socket.tcp();
278 elseif proto == "IPv6" and socket.tcp6 then
279 conn, handler = socket.tcp6();
281 handler = "Unsupported protocol: "..tostring(proto);
285 log("warn", "Failed to create outgoing connection, system error: %s", handler);
286 return false, handler;
290 local success, err = conn:connect(connect_host.addr, connect_port);
291 if not success and err ~= "timeout" then
292 log("warn", "s2s connect() to %s (%s:%d) failed: %s", host_session.to_host, connect_host.addr, connect_port, err);
296 conn = wrapclient(conn, connect_host.addr, connect_port, s2s_listener, "*a");
297 host_session.conn = conn;
299 local filter = initialize_filters(host_session);
300 local w, log = conn.write, host_session.log;
301 host_session.sends2s = function (t)
302 log("debug", "sending: %s", (t.top_tag and t:top_tag()) or t:match("^[^>]*>?"));
304 t = filter("stanzas/out", t);
307 t = filter("bytes/out", tostring(t));
309 return w(conn, tostring(t));
314 -- Register this outgoing connection so that xmppserver_listener knows about it
315 -- otherwise it will assume it is a new incoming connection
316 s2s_listener.register_outgoing(conn, host_session);
318 log("debug", "Connection attempt in progress...");
322 module:hook_global("service-added", function (event)
323 if event.name ~= "s2s" then return end
325 local s2s_sources = portmanager.get_active_services():get("s2s");
326 if not s2s_sources then
327 module:log("warn", "s2s not listening on any ports, outgoing connections may fail");
330 for source, _ in pairs(s2s_sources) do
331 if source == "*" or source == "0.0.0.0" then
332 for _, addr in ipairs(local_addresses("ipv4", true)) do
333 sources[#sources + 1] = new_ip(addr, "IPv4");
335 elseif source == "::" then
336 for _, addr in ipairs(local_addresses("ipv6", true)) do
337 sources[#sources + 1] = new_ip(addr, "IPv6");
340 sources[#sources + 1] = new_ip(source, (source:find(":") and "IPv6") or "IPv4");
343 for i = 1,#sources do
344 if sources[i].proto == "IPv6" then
346 elseif sources[i].proto == "IPv4" then