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);
38 function s2sout.set_listener(listener)
39 s2s_listener = listener;
42 local function compare_srv_priorities(a,b)
43 return a.priority < b.priority or (a.priority == b.priority and a.weight > b.weight);
46 function s2sout.initiate_connection(host_session)
47 initialize_filters(host_session);
48 host_session.version = 1;
50 -- Kick the connection attempting machine into life
51 if not s2sout.attempt_connection(host_session) then
52 -- Intentionally not returning here, the
53 -- session is needed, connected or not
54 s2s_destroy_session(host_session);
57 if not host_session.sends2s then
58 -- A sends2s which buffers data (until the stream is opened)
59 -- note that data in this buffer will be sent before the stream is authed
60 -- and will not be ack'd in any way, successful or otherwise
62 function host_session.sends2s(data)
65 host_session.send_buffer = buffer;
67 log("debug", "Buffering data on unconnected s2sout to %s", tostring(host_session.to_host));
68 buffer[#buffer+1] = data;
69 log("debug", "Buffered item %d: %s", #buffer, tostring(data));
74 function s2sout.attempt_connection(host_session, err)
75 local to_host = host_session.to_host;
76 local connect_host, connect_port = to_host and idna_to_ascii(to_host), 5269;
78 if not connect_host then
82 if not err then -- This is our first attempt
83 log("debug", "First attempt to connect to %s, starting with SRV lookup...", to_host);
84 host_session.connecting = true;
86 handle = adns.lookup(function (answer)
88 host_session.connecting = nil;
89 if answer and #answer > 0 then
90 log("debug", "%s has SRV records, handling...", to_host);
91 local srv_hosts = { answer = answer };
92 host_session.srv_hosts = srv_hosts;
93 for _, record in ipairs(answer) do
94 t_insert(srv_hosts, record.srv);
96 if #srv_hosts == 1 and srv_hosts[1].target == "." then
97 log("debug", "%s does not provide a XMPP service", to_host);
98 s2s_destroy_session(host_session, err); -- Nothing to see here
101 t_sort(srv_hosts, compare_srv_priorities);
103 local srv_choice = srv_hosts[1];
104 host_session.srv_choice = 1;
106 connect_host, connect_port = srv_choice.target or to_host, srv_choice.port or connect_port;
107 log("debug", "Best record found, will connect to %s:%d", connect_host, connect_port);
110 log("debug", "%s has no SRV records, falling back to A/AAAA", to_host);
112 -- Try with SRV, or just the plain hostname if no SRV
113 local ok, err = s2sout.try_connect(host_session, connect_host, connect_port);
115 if not s2sout.attempt_connection(host_session, err) then
116 -- No more attempts will be made
117 s2s_destroy_session(host_session, err);
120 end, "_xmpp-server._tcp."..connect_host..".", "SRV");
122 return true; -- Attempt in progress
123 elseif host_session.ip_hosts then
124 return s2sout.try_connect(host_session, connect_host, connect_port, err);
125 elseif host_session.srv_hosts and #host_session.srv_hosts > host_session.srv_choice then -- Not our first attempt, and we also have SRV
126 host_session.srv_choice = host_session.srv_choice + 1;
127 local srv_choice = host_session.srv_hosts[host_session.srv_choice];
128 connect_host, connect_port = srv_choice.target or to_host, srv_choice.port or connect_port;
129 host_session.log("info", "Connection failed (%s). Attempt #%d: This time to %s:%d", tostring(err), host_session.srv_choice, connect_host, connect_port);
131 host_session.log("info", "Out of connection options, can't connect to %s", tostring(host_session.to_host));
132 -- We're out of options
136 if not (connect_host and connect_port) then
137 -- Likely we couldn't resolve DNS
138 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));
142 return s2sout.try_connect(host_session, connect_host, connect_port);
145 function s2sout.try_next_ip(host_session)
146 host_session.connecting = nil;
147 host_session.ip_choice = host_session.ip_choice + 1;
148 local ip = host_session.ip_hosts[host_session.ip_choice];
149 local ok, err= s2sout.make_connect(host_session, ip.ip, ip.port);
151 if not s2sout.attempt_connection(host_session, err or "closed") then
152 err = err and (": "..err) or "";
153 s2s_destroy_session(host_session, "Connection failed"..err);
158 function s2sout.try_connect(host_session, connect_host, connect_port, err)
159 host_session.connecting = true;
163 host_session.ip_hosts = IPs;
164 local handle4, handle6;
165 local have_other_result = not(has_ipv4) or not(has_ipv6) or false;
168 handle4 = adns.lookup(function (reply, err)
171 if reply and reply[#reply] and reply[#reply].a then
172 for _, ip in ipairs(reply) do
173 log("debug", "DNS reply for %s gives us %s", connect_host, ip.a);
174 IPs[#IPs+1] = new_ip(ip.a, "IPv4");
178 if have_other_result then
180 rfc6724_dest(host_session.ip_hosts, sources);
182 IPs[i] = {ip = IPs[i], port = connect_port};
184 host_session.ip_choice = 0;
185 s2sout.try_next_ip(host_session);
187 log("debug", "DNS lookup failed to get a response for %s", connect_host);
188 host_session.ip_hosts = nil;
189 if not s2sout.attempt_connection(host_session, "name resolution failed") then -- Retry if we can
190 log("debug", "No other records to try for %s - destroying", host_session.to_host);
191 err = err and (": "..err) or "";
192 s2s_destroy_session(host_session, "DNS resolution failed"..err); -- End of the line, we can't
196 have_other_result = true;
198 end, connect_host, "A", "IN");
200 have_other_result = true;
204 handle6 = adns.lookup(function (reply, err)
207 if reply and reply[#reply] and reply[#reply].aaaa then
208 for _, ip in ipairs(reply) do
209 log("debug", "DNS reply for %s gives us %s", connect_host, ip.aaaa);
210 IPs[#IPs+1] = new_ip(ip.aaaa, "IPv6");
214 if have_other_result then
216 rfc6724_dest(host_session.ip_hosts, sources);
218 IPs[i] = {ip = IPs[i], port = connect_port};
220 host_session.ip_choice = 0;
221 s2sout.try_next_ip(host_session);
223 log("debug", "DNS lookup failed to get a response for %s", connect_host);
224 host_session.ip_hosts = nil;
225 if not s2sout.attempt_connection(host_session, "name resolution failed") then -- Retry if we can
226 log("debug", "No other records to try for %s - destroying", host_session.to_host);
227 err = err and (": "..err) or "";
228 s2s_destroy_session(host_session, "DNS resolution failed"..err); -- End of the line, we can't
232 have_other_result = true;
234 end, connect_host, "AAAA", "IN");
236 have_other_result = true;
239 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
240 s2sout.try_next_ip(host_session);
242 host_session.ip_hosts = nil;
243 if not s2sout.attempt_connection(host_session, "out of IP addresses") then -- Retry if we can
244 log("debug", "No other records to try for %s - destroying", host_session.to_host);
245 err = err and (": "..err) or "";
246 s2s_destroy_session(host_session, "Connecting failed"..err); -- End of the line, we can't
254 function s2sout.make_connect(host_session, connect_host, connect_port)
255 (host_session.log or log)("info", "Beginning new connection attempt to %s ([%s]:%d)", host_session.to_host, connect_host.addr, connect_port);
257 -- Reset secure flag in case this is another
258 -- connection attempt after a failed STARTTLS
259 host_session.secure = nil;
262 local proto = connect_host.proto;
263 if proto == "IPv4" then
264 conn, handler = socket.tcp();
265 elseif proto == "IPv6" and socket.tcp6 then
266 conn, handler = socket.tcp6();
268 handler = "Unsupported protocol: "..tostring(proto);
272 log("warn", "Failed to create outgoing connection, system error: %s", handler);
273 return false, handler;
277 local success, err = conn:connect(connect_host.addr, connect_port);
278 if not success and err ~= "timeout" then
279 log("warn", "s2s connect() to %s (%s:%d) failed: %s", host_session.to_host, connect_host.addr, connect_port, err);
283 conn = wrapclient(conn, connect_host.addr, connect_port, s2s_listener, "*a");
284 host_session.conn = conn;
286 local filter = initialize_filters(host_session);
287 local w, log = conn.write, host_session.log;
288 host_session.sends2s = function (t)
289 log("debug", "sending: %s", (t.top_tag and t:top_tag()) or t:match("^[^>]*>?"));
291 t = filter("stanzas/out", t);
294 t = filter("bytes/out", tostring(t));
296 return w(conn, tostring(t));
301 -- Register this outgoing connection so that xmppserver_listener knows about it
302 -- otherwise it will assume it is a new incoming connection
303 s2s_listener.register_outgoing(conn, host_session);
305 log("debug", "Connection attempt in progress...");
309 module:hook_global("service-added", function (event)
310 if event.name ~= "s2s" then return end
312 local s2s_sources = portmanager.get_active_services():get("s2s");
313 if not s2s_sources then
314 module:log("warn", "s2s not listening on any ports, outgoing connections may fail");
317 for source, _ in pairs(s2s_sources) do
318 if source == "*" or source == "0.0.0.0" then
319 for _, addr in ipairs(local_addresses("ipv4", true)) do
320 sources[#sources + 1] = new_ip(addr, "IPv4");
322 elseif source == "::" then
323 for _, addr in ipairs(local_addresses("ipv6", true)) do
324 sources[#sources + 1] = new_ip(addr, "IPv6");
327 sources[#sources + 1] = new_ip(source, (source:find(":") and "IPv6") or "IPv4");
330 for i = 1,#sources do
331 if sources[i].proto == "IPv6" then
333 elseif sources[i].proto == "IPv4" then
337 if not (has_ipv4 or has_ipv6) then
338 module:log("warn", "No local IPv4 or IPv6 addresses detected, outgoing connections may fail");