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;
22 local s2s_destroy_session = require "core.s2smanager".destroy_session;
24 local log = module._log;
26 local anysource = { IPv4 = "0.0.0.0", IPv6 = "::" };
27 local function get_sources(addrs)
29 for _, IP in ipairs(addrs) do
31 if IP.proto == "IPv4" then
33 elseif IP.proto == "IPv6" then
36 sock:setpeername(IP.addr, 9);
37 local localaddr = sock:getsockname() or anysource[IP.proto];
39 if not sources[localaddr] then
40 sources[localaddr] = true;
41 t_insert(sources, new_ip(localaddr, IP.proto));
46 local has_ipv4, has_ipv6;
48 local dns_timeout = module:get_option_number("dns_timeout", 15);
49 dns.settimeout(dns_timeout);
56 function s2sout.set_listener(listener)
57 s2s_listener = listener;
60 local function compare_srv_priorities(a,b)
61 return a.priority < b.priority or (a.priority == b.priority and a.weight > b.weight);
64 function s2sout.initiate_connection(host_session)
65 initialize_filters(host_session);
66 host_session.version = 1;
68 -- Kick the connection attempting machine into life
69 if not s2sout.attempt_connection(host_session) then
70 -- Intentionally not returning here, the
71 -- session is needed, connected or not
72 s2s_destroy_session(host_session);
75 if not host_session.sends2s then
76 -- A sends2s which buffers data (until the stream is opened)
77 -- note that data in this buffer will be sent before the stream is authed
78 -- and will not be ack'd in any way, successful or otherwise
80 function host_session.sends2s(data)
83 host_session.send_buffer = buffer;
85 log("debug", "Buffering data on unconnected s2sout to %s", tostring(host_session.to_host));
86 buffer[#buffer+1] = data;
87 log("debug", "Buffered item %d: %s", #buffer, tostring(data));
92 function s2sout.attempt_connection(host_session, err)
93 local to_host = host_session.to_host;
94 local connect_host, connect_port = to_host and idna_to_ascii(to_host), 5269;
96 if not connect_host then
100 if not err then -- This is our first attempt
101 log("debug", "First attempt to connect to %s, starting with SRV lookup...", to_host);
102 host_session.connecting = true;
104 handle = adns.lookup(function (answer)
106 local srv_hosts = { answer = answer };
107 host_session.srv_hosts = srv_hosts;
108 host_session.srv_choice = 0;
109 host_session.connecting = nil;
110 if answer and #answer > 0 then
111 log("debug", "%s has SRV records, handling...", to_host);
112 for _, record in ipairs(answer) do
113 t_insert(srv_hosts, record.srv);
115 if #srv_hosts == 1 and srv_hosts[1].target == "." then
116 log("debug", "%s does not provide a XMPP service", to_host);
117 s2s_destroy_session(host_session, err); -- Nothing to see here
120 t_sort(srv_hosts, compare_srv_priorities);
122 local srv_choice = srv_hosts[1];
123 host_session.srv_choice = 1;
125 connect_host, connect_port = srv_choice.target or to_host, srv_choice.port or connect_port;
126 log("debug", "Best record found, will connect to %s:%d", connect_host, connect_port);
129 log("debug", "%s has no SRV records, falling back to A/AAAA", to_host);
131 -- Try with SRV, or just the plain hostname if no SRV
132 local ok, err = s2sout.try_connect(host_session, connect_host, connect_port);
134 if not s2sout.attempt_connection(host_session, err) then
135 -- No more attempts will be made
136 s2s_destroy_session(host_session, err);
139 end, "_xmpp-server._tcp."..connect_host..".", "SRV");
141 return true; -- Attempt in progress
142 elseif host_session.ip_hosts then
143 return s2sout.try_connect(host_session, connect_host, connect_port, err);
144 elseif host_session.srv_hosts and #host_session.srv_hosts > host_session.srv_choice then -- Not our first attempt, and we also have SRV
145 host_session.srv_choice = host_session.srv_choice + 1;
146 local srv_choice = host_session.srv_hosts[host_session.srv_choice];
147 connect_host, connect_port = srv_choice.target or to_host, srv_choice.port or connect_port;
148 host_session.log("info", "Connection failed (%s). Attempt #%d: This time to %s:%d", tostring(err), host_session.srv_choice, connect_host, connect_port);
150 host_session.log("info", "Failed in all attempts to connect to %s", tostring(host_session.to_host));
151 -- We're out of options
155 if not (connect_host and connect_port) then
156 -- Likely we couldn't resolve DNS
157 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));
161 return s2sout.try_connect(host_session, connect_host, connect_port);
164 function s2sout.try_next_ip(host_session)
165 host_session.connecting = nil;
166 host_session.ip_choice = host_session.ip_choice + 1;
167 local ip = host_session.ip_hosts[host_session.ip_choice];
168 local ok, err= s2sout.make_connect(host_session, ip.ip, ip.port);
170 if not s2sout.attempt_connection(host_session, err or "closed") then
171 err = err and (": "..err) or "";
172 s2s_destroy_session(host_session, "Connection failed"..err);
177 function s2sout.try_connect(host_session, connect_host, connect_port, err)
178 host_session.connecting = true;
182 host_session.ip_hosts = IPs;
183 local handle4, handle6;
184 local have_other_result = not(has_ipv4) or not(has_ipv6) or false;
187 handle4 = adns.lookup(function (reply, err)
190 if reply and reply[#reply] and reply[#reply].a then
191 for _, ip in ipairs(reply) do
192 log("debug", "DNS reply for %s gives us %s", connect_host, ip.a);
193 IPs[#IPs+1] = new_ip(ip.a, "IPv4");
197 if have_other_result then
199 rfc6724_dest(host_session.ip_hosts, get_sources(host_session.ip_hosts));
201 IPs[i] = {ip = IPs[i], port = connect_port};
203 host_session.ip_choice = 0;
204 s2sout.try_next_ip(host_session);
206 log("debug", "DNS lookup failed to get a response for %s", connect_host);
207 host_session.ip_hosts = nil;
208 if not s2sout.attempt_connection(host_session, "name resolution failed") then -- Retry if we can
209 log("debug", "No other records to try for %s - destroying", host_session.to_host);
210 err = err and (": "..err) or "";
211 s2s_destroy_session(host_session, "DNS resolution failed"..err); -- End of the line, we can't
215 have_other_result = true;
217 end, connect_host, "A", "IN");
219 have_other_result = true;
223 handle6 = adns.lookup(function (reply, err)
226 if reply and reply[#reply] and reply[#reply].aaaa then
227 for _, ip in ipairs(reply) do
228 log("debug", "DNS reply for %s gives us %s", connect_host, ip.aaaa);
229 IPs[#IPs+1] = new_ip(ip.aaaa, "IPv6");
233 if have_other_result then
235 rfc6724_dest(host_session.ip_hosts, get_sources(host_session.ip_hosts));
237 IPs[i] = {ip = IPs[i], port = connect_port};
239 host_session.ip_choice = 0;
240 s2sout.try_next_ip(host_session);
242 log("debug", "DNS lookup failed to get a response for %s", connect_host);
243 host_session.ip_hosts = nil;
244 if not s2sout.attempt_connection(host_session, "name resolution failed") then -- Retry if we can
245 log("debug", "No other records to try for %s - destroying", host_session.to_host);
246 err = err and (": "..err) or "";
247 s2s_destroy_session(host_session, "DNS resolution failed"..err); -- End of the line, we can't
251 have_other_result = true;
253 end, connect_host, "AAAA", "IN");
255 have_other_result = true;
258 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
259 s2sout.try_next_ip(host_session);
261 host_session.ip_hosts = nil;
262 if not s2sout.attempt_connection(host_session, "out of IP addresses") then -- Retry if we can
263 log("debug", "No other records to try for %s - destroying", host_session.to_host);
264 err = err and (": "..err) or "";
265 s2s_destroy_session(host_session, "Connecting failed"..err); -- End of the line, we can't
273 function s2sout.make_connect(host_session, connect_host, connect_port)
274 (host_session.log or log)("debug", "Beginning new connection attempt to %s ([%s]:%d)", host_session.to_host, connect_host.addr, connect_port);
276 -- Reset secure flag in case this is another
277 -- connection attempt after a failed STARTTLS
278 host_session.secure = nil;
279 host_session.encrypted = nil;
282 local proto = connect_host.proto;
283 if proto == "IPv4" then
284 conn, handler = socket.tcp();
285 elseif proto == "IPv6" and socket.tcp6 then
286 conn, handler = socket.tcp6();
288 handler = "Unsupported protocol: "..tostring(proto);
292 log("warn", "Failed to create outgoing connection, system error: %s", handler);
293 return false, handler;
297 local success, err = conn:connect(connect_host.addr, connect_port);
298 if not success and err ~= "timeout" then
299 log("warn", "s2s connect() to %s (%s:%d) failed: %s", host_session.to_host, connect_host.addr, connect_port, err);
303 conn = wrapclient(conn, connect_host.addr, connect_port, s2s_listener, "*a");
304 host_session.conn = conn;
306 -- Register this outgoing connection so that xmppserver_listener knows about it
307 -- otherwise it will assume it is a new incoming connection
308 s2s_listener.register_outgoing(conn, host_session);
310 log("debug", "Connection attempt in progress...");
314 module:hook_global("service-added", function (event)
315 if event.name ~= "s2s" then return end
317 local s2s_sources = portmanager.get_active_services():get("s2s");
318 if not s2s_sources then
319 module:log("warn", "s2s not listening on any ports, outgoing connections may fail");
322 for source, _ in pairs(s2s_sources) do
323 if source:find(":") then