core/s2smanager.lua

   1 -- Prosody IM v0.2
   2 -- Copyright (C) 2008 Matthew Wild
   3 -- Copyright (C) 2008 Waqas Hussain
   4 --
   5 -- This program is free software; you can redistribute it and/or
   6 -- modify it under the terms of the GNU General Public License
   7 -- as published by the Free Software Foundation; either version 2
   8 -- of the License, or (at your option) any later version.
   9 --
  10 -- This program is distributed in the hope that it will be useful,
  11 -- but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 -- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 -- GNU General Public License for more details.
  14 --
  15 -- You should have received a copy of the GNU General Public License
  16 -- along with this program; if not, write to the Free Software
  17 -- Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  18 --
  19
  20
  21
  22 local hosts = hosts;
  23 local sessions = sessions;
  24 local core_process_stanza = function(a, b) core_process_stanza(a, b); end
  25 local socket = require "socket";
  26 local format = string.format;
  27 local t_insert, t_sort = table.insert, table.sort;
  28 local get_traceback = debug.traceback;
  29 local tostring, pairs, ipairs, getmetatable, print, newproxy, error, tonumber
  30     = tostring, pairs, ipairs, getmetatable, print, newproxy, error, tonumber;
  31
  32 local idna_to_ascii = require "util.encodings".idna.to_ascii;
  33 local connlisteners_get = require "net.connlisteners".get;
  34 local wraptlsclient = require "net.server".wraptlsclient;
  35 local modulemanager = require "core.modulemanager";
  36 local st = require "stanza";
  37 local stanza = st.stanza;
  38
  39 local uuid_gen = require "util.uuid".generate;
  40
  41 local logger_init = require "util.logger".init;
  42
  43 local log = logger_init("s2smanager");
  44
  45 local sha256_hash = require "util.hashes".sha256;
  46
  47 local dialback_secret = sha256_hash(tostring{} .. math.random() .. socket.gettime(), true);
  48
  49 local dns = require "net.dns";
  50
  51 incoming_s2s = {};
  52 local incoming_s2s = incoming_s2s;
  53
  54 module "s2smanager"
  55
  56 local function compare_srv_priorities(a,b) return a.priority < b.priority or a.weight < b.weight; end
  57
  58 local function bounce_sendq(session)
  59         local sendq = session.sendq;
  60         if sendq then
  61                 session.log("debug", "sending error replies for "..#sendq.." queued stanzas because of failed outgoing connection to "..tostring(session.to_host));
  62                 local dummy = {
  63                         type = "s2sin";
  64                         send = function(s)
  65                                 (session.log or log)("error", "Replying to to an s2s error reply, please report this! Traceback: %s", get_traceback());
  66                         end;
  67                         dummy = true;
  68                 };
  69                 for i, data in ipairs(sendq) do
  70                         local reply = data[2];
  71                         local xmlns = reply.attr.xmlns;
  72                         if not xmlns or xmlns == "jabber:client" or xmlns == "jabber:server" then
  73                                 reply.attr.type = "error";
  74                                 reply:tag("error", {type = "cancel"})
  75                                         :tag("remote-server-not-found", {xmlns = "urn:ietf:params:xml:ns:xmpp-stanzas"}):up();
  76                                 core_process_stanza(dummy, reply);
  77                         end
  78                         sendq[i] = nil;
  79                 end
  80                 session.sendq = nil;
  81         end
  82 end
  83
  84 function send_to_host(from_host, to_host, data)
  85         local host = hosts[from_host].s2sout[to_host];
  86         if host then
  87                 -- We have a connection to this host already
  88                 if host.type == "s2sout_unauthed" and data.name ~= "db:verify" and ((not data.xmlns) or data.xmlns == "jabber:client" or data.xmlns == "jabber:server") then
  89                         (host.log or log)("debug", "trying to send over unauthed s2sout to "..to_host);
  90                         if not host.notopen and not host.dialback_key then
  91                                 host.log("debug", "dialback had not been initiated");
  92                                 initiate_dialback(host);
  93                         end
  94
  95                         -- Queue stanza until we are able to send it
  96                         if host.sendq then t_insert(host.sendq, {tostring(data), st.reply(data)});
  97                         else host.sendq = { {tostring(data), st.reply(data)} }; end
  98                         host.log("debug", "stanza [%s] queued ", data.name);
  99                 elseif host.type == "local" or host.type == "component" then
 100                         log("error", "Trying to send a stanza to ourselves??")
 101                         log("error", "Traceback: %s", get_traceback());
 102                         log("error", "Stanza: %s", tostring(data));
 103                 else
 104                         (host.log or log)("debug", "going to send stanza to "..to_host.." from "..from_host);
 105                         -- FIXME
 106                         if host.from_host ~= from_host then
 107                                 log("error", "WARNING! This might, possibly, be a bug, but it might not...");
 108                                 log("error", "We are going to send from %s instead of %s", tostring(host.from_host), tostring(from_host));
 109                         end
 110                         host.sends2s(data);
 111                         host.log("debug", "stanza sent over "..host.type);
 112                 end
 113         else
 114                 log("debug", "opening a new outgoing connection for this stanza");
 115                 local host_session = new_outgoing(from_host, to_host);
 116                 -- Store in buffer
 117                 host_session.sendq = { {tostring(data), st.reply(data)} };
 118                 if not host_session.conn then destroy_session(host_session); end
 119         end
 120 end
 121
 122 local open_sessions = 0;
 123
 124 function new_incoming(conn)
 125         local session = { conn = conn, type = "s2sin_unauthed", direction = "incoming", hosts = {} };
 126         if true then
 127                 session.trace = newproxy(true);
 128                 getmetatable(session.trace).__gc = function () open_sessions = open_sessions - 1; end;
 129         end
 130         open_sessions = open_sessions + 1;
 131         local w, log = conn.write, logger_init("s2sin"..tostring(conn):match("[a-f0-9]+$"));
 132         session.sends2s = function (t) log("debug", "sending: %s", tostring(t)); w(tostring(t)); end
 133         incoming_s2s[session] = true;
 134         return session;
 135 end
 136
 137 function new_outgoing(from_host, to_host)
 138                 local host_session = { to_host = to_host, from_host = from_host, notopen = true, type = "s2sout_unauthed", direction = "outgoing" };
 139                 hosts[from_host].s2sout[to_host] = host_session;
 140
 141                 local log;
 142                 do
 143                         local conn_name = "s2sout"..tostring(host_session):match("[a-f0-9]*$");
 144                         log = logger_init(conn_name);
 145                         host_session.log = log;
 146                 end
 147
 148                 attempt_connection(host_session);
 149
 150                 return host_session;
 151 end
 152
 153
 154 function attempt_connection(host_session, err)
 155         local from_host, to_host = host_session.from_host, host_session.to_host;
 156         local conn, handler = socket.tcp()
 157
 158         local connect_host, connect_port = idna_to_ascii(to_host), 5269;
 159
 160         if not err then -- This is our first attempt
 161                 local answer = dns.lookup("_xmpp-server._tcp."..connect_host..".", "SRV");
 162
 163                 if answer then
 164                         log("debug", to_host.." has SRV records, handling...");
 165                         local srv_hosts = {};
 166                         host_session.srv_hosts = srv_hosts;
 167                         for _, record in ipairs(answer) do
 168                                 t_insert(srv_hosts, record.srv);
 169                         end
 170                         t_sort(srv_hosts, compare_srv_priorities);
 171
 172                         local srv_choice = srv_hosts[1];
 173                         host_session.srv_choice = 1;
 174                         if srv_choice then
 175                                 connect_host, connect_port = srv_choice.target or to_host, srv_choice.port or connect_port;
 176                                 log("debug", "Best record found, will connect to %s:%d", connect_host, connect_port);
 177                         end
 178                 end
 179         elseif host_session.srv_hosts and #host_session.srv_hosts > host_session.srv_choice then -- Not our first attempt, and we also have SRV
 180                 host_session.srv_choice = host_session.srv_choice + 1;
 181                 local srv_choice = host_session.srv_hosts[host_session.srv_choice];
 182                 connect_host, connect_port = srv_choice.target or to_host, srv_choice.port or connect_port;
 183                 host_session.log("debug", "Connection failed (%s). Attempt #%d: This time to %s:%d", tostring(err), host_session.srv_choice, connect_host, connect_port);
 184         else
 185                 host_session.log("debug", "Out of connection options, can't connect to %s", tostring(host_session.to_host));
 186                 -- We're out of options
 187                 return false;
 188         end
 189
 190         -- Ok, we're going to try to connect
 191         conn:settimeout(0);
 192         local success, err = conn:connect(connect_host, connect_port);
 193         if not success and err ~= "timeout" then
 194                 log("warn", "s2s connect() failed: %s", err);
 195                 return false;
 196         end
 197
 198         local cl = connlisteners_get("xmppserver");
 199         conn = wraptlsclient(cl, conn, connect_host, connect_port, 0, cl.default_mode or 1, hosts[from_host].ssl_ctx );
 200         host_session.conn = conn;
 201
 202         -- Register this outgoing connection so that xmppserver_listener knows about it
 203         -- otherwise it will assume it is a new incoming connection
 204         cl.register_outgoing(conn, host_session);
 205
 206         local w = conn.write;
 207         host_session.sends2s = function (t) log("debug", "sending: %s", tostring(t)); w(tostring(t)); end
 208
 209         conn.write(format([[<stream:stream xmlns='jabber:server' xmlns:db='jabber:server:dialback' xmlns:stream='http://etherx.jabber.org/streams' from='%s' to='%s' version='1.0'>]], from_host, to_host));
 210         return true;
 211 end
 212
 213 function streamopened(session, attr)
 214         local send = session.sends2s;
 215
 216         -- TODO: #29: SASL/TLS on s2s streams
 217         session.version = 0; --tonumber(attr.version) or 0;
 218
 219         if session.version >= 1.0 and not (attr.to and attr.from) then
 220                 --print("to: "..tostring(attr.to).." from: "..tostring(attr.from));
 221                 log("warn", (session.to_host or "(unknown)").." failed to specify 'to' or 'from' hostname as per RFC");
 222         end
 223
 224         if session.direction == "incoming" then
 225                 -- Send a reply stream header
 226
 227                 --for k,v in pairs(attr) do print("", tostring(k), ":::", tostring(v)); end
 228
 229                 session.to_host = attr.to;
 230                 session.from_host = attr.from;
 231
 232                 session.streamid = uuid_gen();
 233                 (session.log or log)("debug", "incoming s2s received <stream:stream>");
 234                 send("<?xml version='1.0'?>");
 235                 send(stanza("stream:stream", { xmlns='jabber:server', ["xmlns:db"]='jabber:server:dialback', ["xmlns:stream"]='http://etherx.jabber.org/streams', id=session.streamid, from=session.to_host }):top_tag());
 236                 if session.to_host and not hosts[session.to_host] then
 237                         -- Attempting to connect to a host we don't serve
 238                         session:close({ condition = "host-unknown"; text = "This host does not serve "..session.to_host });
 239                         return;
 240                 end
 241                 if session.version >= 1.0 then
 242                         send(st.stanza("stream:features")
 243                                         :tag("dialback", { xmlns='urn:xmpp:features:dialback' }):tag("optional"):up():up());
 244                 end
 245         elseif session.direction == "outgoing" then
 246                 -- If we are just using the connection for verifying dialback keys, we won't try and auth it
 247                 if not attr.id then error("stream response did not give us a streamid!!!"); end
 248                 session.streamid = attr.id;
 249
 250                 if not session.dialback_verifying then
 251                         initiate_dialback(session);
 252                 else
 253                         mark_connected(session);
 254                 end
 255         end
 256
 257         session.notopen = nil;
 258 end
 259
 260 function initiate_dialback(session)
 261         -- generate dialback key
 262         session.dialback_key = generate_dialback(session.streamid, session.to_host, session.from_host);
 263         session.sends2s(format("<db:result from='%s' to='%s'>%s</db:result>", session.from_host, session.to_host, session.dialback_key));
 264         session.log("info", "sent dialback key on outgoing s2s stream");
 265 end
 266
 267 function generate_dialback(id, to, from)
 268         return sha256_hash(id..to..from..dialback_secret, true);
 269 end
 270
 271 function verify_dialback(id, to, from, key)
 272         return key == generate_dialback(id, to, from);
 273 end
 274
 275 function make_authenticated(session, host)
 276         if session.type == "s2sout_unauthed" then
 277                 session.type = "s2sout";
 278         elseif session.type == "s2sin_unauthed" then
 279                 session.type = "s2sin";
 280                 if host then
 281                         session.hosts[host].authed = true;
 282                 end
 283         elseif session.type == "s2sin" and host then
 284                 session.hosts[host].authed = true;
 285         else
 286                 return false;
 287         end
 288         session.log("info", "connection is now authenticated");
 289
 290         mark_connected(session);
 291
 292         return true;
 293 end
 294
 295 function mark_connected(session)
 296         local sendq, send = session.sendq, session.sends2s;
 297
 298         local from, to = session.from_host, session.to_host;
 299
 300         session.log("debug", session.direction.." s2s connection "..from.."->"..to.." is now complete");
 301
 302         local send_to_host = send_to_host;
 303         function session.send(data) send_to_host(to, from, data); end
 304
 305
 306         if session.direction == "outgoing" then
 307                 if sendq then
 308                         session.log("debug", "sending "..#sendq.." queued stanzas across new outgoing connection to "..session.to_host);
 309                         for i, data in ipairs(sendq) do
 310                                 send(data[1]);
 311                                 sendq[i] = nil;
 312                         end
 313                         session.sendq = nil;
 314                 end
 315         end
 316 end
 317
 318 function destroy_session(session)
 319         (session.log or log)("info", "Destroying "..tostring(session.direction).." session "..tostring(session.from_host).."->"..tostring(session.to_host));
 320
 321
 322         if session.direction == "outgoing" then
 323                 hosts[session.from_host].s2sout[session.to_host] = nil;
 324                 bounce_sendq(session);
 325         elseif session.direction == "incoming" then
 326                 incoming_s2s[session] = nil;
 327         end
 328
 329         for k in pairs(session) do
 330                 if k ~= "trace" then
 331                         session[k] = nil;
 332                 end
 333         end
 334 end
 335
 336 return _M;