core/s2smanager.lua

   1
   2 local hosts = hosts;
   3 local sessions = sessions;
   4 local socket = require "socket";
   5 local format = string.format;
   6 local t_insert, t_sort = table.insert, table.sort;
   7 local get_traceback = debug.traceback;
   8 local tostring, pairs, ipairs, getmetatable, print, newproxy, error, tonumber
   9     = tostring, pairs, ipairs, getmetatable, print, newproxy, error, tonumber;
  10
  11 local idna_to_ascii = require "util.encodings".idna.to_ascii;
  12 local connlisteners_get = require "net.connlisteners".get;
  13 local wraptlsclient = require "net.server".wraptlsclient;
  14 local modulemanager = require "core.modulemanager";
  15 local st = require "stanza";
  16 local stanza = st.stanza;
  17
  18 local uuid_gen = require "util.uuid".generate;
  19
  20 local logger_init = require "util.logger".init;
  21
  22 local log = logger_init("s2smanager");
  23
  24 local sha256_hash = require "util.hashes".sha256;
  25
  26 local dialback_secret = "This is very secret!!! Ha!";
  27
  28 local dns = require "net.dns";
  29
  30 module "s2smanager"
  31
  32 local function compare_srv_priorities(a,b) return a.priority < b.priority or a.weight < b.weight; end
  33
  34 function send_to_host(from_host, to_host, data)
  35         if data.name then data = tostring(data); end
  36         local host = hosts[from_host].s2sout[to_host];
  37         if host then
  38                 -- We have a connection to this host already
  39                 if host.type == "s2sout_unauthed" and ((not data.xmlns) or data.xmlns == "jabber:client" or data.xmlns == "jabber:server") then
  40                         (host.log or log)("debug", "trying to send over unauthed s2sout to "..to_host..", authing it now...");
  41                         if not host.notopen and not host.dialback_key then
  42                                 host.log("debug", "dialback had not been initiated");
  43                                 initiate_dialback(host);
  44                         end
  45
  46                         -- Queue stanza until we are able to send it
  47                         if host.sendq then t_insert(host.sendq, data);
  48                         else host.sendq = { data }; end
  49                 elseif host.type == "local" or host.type == "component" then
  50                         log("error", "Trying to send a stanza to ourselves??")
  51                         log("error", "Traceback: %s", get_traceback());
  52                         log("error", "Stanza: %s", tostring(data));
  53                 else
  54                         (host.log or log)("debug", "going to send stanza to "..to_host.." from "..from_host);
  55                         -- FIXME
  56                         if host.from_host ~= from_host then
  57                                 log("error", "WARNING! This might, possibly, be a bug, but it might not...");
  58                                 log("error", "We are going to send from %s instead of %s", tostring(host.from_host), tostring(from_host));
  59                         end
  60                         host.sends2s(data);
  61                         host.log("debug", "stanza sent over "..host.type);
  62                 end
  63         else
  64                 log("debug", "opening a new outgoing connection for this stanza");
  65                 local host_session = new_outgoing(from_host, to_host);
  66                 -- Store in buffer
  67                 host_session.sendq = { data };
  68         end
  69 end
  70
  71 local open_sessions = 0;
  72
  73 function new_incoming(conn)
  74         local session = { conn = conn, type = "s2sin_unauthed", direction = "incoming" };
  75         if true then
  76                 session.trace = newproxy(true);
  77                 getmetatable(session.trace).__gc = function () open_sessions = open_sessions - 1; print("s2s session got collected, now "..open_sessions.." s2s sessions are allocated") end;
  78         end
  79         open_sessions = open_sessions + 1;
  80         local w, log = conn.write, logger_init("s2sin"..tostring(conn):match("[a-f0-9]+$"));
  81         session.sends2s = function (t) log("debug", "sending: %s", tostring(t)); w(tostring(t)); end
  82         return session;
  83 end
  84
  85 function new_outgoing(from_host, to_host)
  86                 local host_session = { to_host = to_host, from_host = from_host, notopen = true, type = "s2sout_unauthed", direction = "outgoing" };
  87                 hosts[from_host].s2sout[to_host] = host_session;
  88
  89                 local log;
  90                 do
  91                         local conn_name = "s2sout"..tostring(conn):match("[a-f0-9]*$");
  92                         log = logger_init(conn_name);
  93                         host_session.log = log;
  94                 end
  95
  96                 attempt_connection(host_session);
  97
  98                 return host_session;
  99 end
 100
 101
 102 function attempt_connection(host_session, err)
 103         local from_host, to_host = host_session.from_host, host_session.to_host;
 104         local conn, handler = socket.tcp()
 105
 106         local connect_host, connect_port = idna_to_ascii(to_host), 5269;
 107
 108         if not err then -- This is our first attempt
 109                 local answer = dns.lookup("_xmpp-server._tcp."..connect_host..".", "SRV");
 110
 111                 if answer then
 112                         log("debug", to_host.." has SRV records, handling...");
 113                         local srv_hosts = {};
 114                         host_session.srv_hosts = srv_hosts;
 115                         for _, record in ipairs(answer) do
 116                                 t_insert(srv_hosts, record.srv);
 117                         end
 118                         t_sort(srv_hosts, compare_srv_priorities);
 119
 120                         local srv_choice = srv_hosts[1];
 121                         host_session.srv_choice = 1;
 122                         if srv_choice then
 123                                 connect_host, connect_port = srv_choice.target or to_host, srv_choice.port or connect_port;
 124                                 log("debug", "Best record found, will connect to %s:%d", connect_host, connect_port);
 125                         end
 126                 end
 127         elseif host_session.srv_hosts and #host_session.srv_hosts > host_session.srv_choice then -- Not our first attempt, and we also have SRV
 128                 host_session.srv_choice = host_session.srv_choice + 1;
 129                 local srv_choice = host_session.srv_hosts[host_session.srv_choice];
 130                 connect_host, connect_port = srv_choice.target or to_host, srv_choice.port or connect_port;
 131                 host_session.log("debug", "Connection failed (%s). Attempt #%d: This time to %s:%d", tostring(err), host_session.srv_choice, connect_host, connect_port);
 132         else
 133                 host_session.log("debug", "Out of connection options, can't connect to %s", tostring(host_session.to_host));
 134                 -- We're out of options
 135                 return false;
 136         end
 137
 138         -- Ok, we're going to try to connect
 139         conn:settimeout(0);
 140         local success, err = conn:connect(connect_host, connect_port);
 141         if not success and err ~= "timeout" then
 142                 log("warn", "s2s connect() failed: %s", err);
 143         end
 144
 145         local cl = connlisteners_get("xmppserver");
 146         conn = wraptlsclient(cl, conn, connect_host, connect_port, 0, cl.default_mode or 1, hosts[from_host].ssl_ctx );
 147         host_session.conn = conn;
 148
 149         -- Register this outgoing connection so that xmppserver_listener knows about it
 150         -- otherwise it will assume it is a new incoming connection
 151         cl.register_outgoing(conn, host_session);
 152
 153         local w = conn.write;
 154         host_session.sends2s = function (t) log("debug", "sending: %s", tostring(t)); w(tostring(t)); end
 155
 156         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));
 157         return true;
 158 end
 159
 160 function streamopened(session, attr)
 161         local send = session.sends2s;
 162
 163         session.version = tonumber(attr.version) or 0;
 164         if session.version >= 1.0 and not (attr.to and attr.from) then
 165                 --print("to: "..tostring(attr.to).." from: "..tostring(attr.from));
 166                 log("warn", (session.to_host or "(unknown)").." failed to specify 'to' or 'from' hostname as per RFC");
 167         end
 168
 169         if session.direction == "incoming" then
 170                 -- Send a reply stream header
 171
 172                 --for k,v in pairs(attr) do print("", tostring(k), ":::", tostring(v)); end
 173
 174                 session.to_host = attr.to;
 175                 session.from_host = attr.from;
 176
 177                 session.streamid = uuid_gen();
 178                 (session.log or log)("debug", "incoming s2s received <stream:stream>");
 179                 send("<?xml version='1.0'?>");
 180                 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());
 181                 if session.to_host and not hosts[session.to_host] then
 182                         -- Attempting to connect to a host we don't serve
 183                         session:close({ condition = "host-unknown"; text = "This host does not serve "..session.to_host });
 184                         return;
 185                 end
 186                 if session.version >= 1.0 then
 187                         send(st.stanza("stream:features")
 188                                         :tag("dialback", { xmlns='urn:xmpp:features:dialback' }):tag("optional"):up():up());
 189                 end
 190         elseif session.direction == "outgoing" then
 191                 -- If we are just using the connection for verifying dialback keys, we won't try and auth it
 192                 if not attr.id then error("stream response did not give us a streamid!!!"); end
 193                 session.streamid = attr.id;
 194
 195                 if not session.dialback_verifying then
 196                         initiate_dialback(session);
 197                 else
 198                         mark_connected(session);
 199                 end
 200         end
 201
 202         session.notopen = nil;
 203 end
 204
 205 function initiate_dialback(session)
 206         -- generate dialback key
 207         session.dialback_key = generate_dialback(session.streamid, session.to_host, session.from_host);
 208         session.sends2s(format("<db:result from='%s' to='%s'>%s</db:result>", session.from_host, session.to_host, session.dialback_key));
 209         session.log("info", "sent dialback key on outgoing s2s stream");
 210 end
 211
 212 function generate_dialback(id, to, from)
 213         return sha256_hash(id..to..from..dialback_secret, true);
 214 end
 215
 216 function verify_dialback(id, to, from, key)
 217         return key == generate_dialback(id, to, from);
 218 end
 219
 220 function make_authenticated(session)
 221         if session.type == "s2sout_unauthed" then
 222                 session.type = "s2sout";
 223         elseif session.type == "s2sin_unauthed" then
 224                 session.type = "s2sin";
 225         else
 226                 return false;
 227         end
 228         session.log("info", "connection is now authenticated");
 229
 230         mark_connected(session);
 231
 232         return true;
 233 end
 234
 235 function mark_connected(session)
 236         local sendq, send = session.sendq, session.sends2s;
 237
 238         local from, to = session.from_host, session.to_host;
 239
 240         session.log("debug", session.direction.." s2s connection "..from.."->"..to.." is now complete");
 241
 242         local send_to_host = send_to_host;
 243         function session.send(data) send_to_host(to, from, data); end
 244
 245
 246         if session.direction == "outgoing" then
 247                 if sendq then
 248                         session.log("debug", "sending "..#sendq.." queued stanzas across new outgoing connection to "..session.to_host);
 249                         for i, data in ipairs(sendq) do
 250                                 send(data);
 251                                 sendq[i] = nil;
 252                         end
 253                         session.sendq = nil;
 254                 end
 255         end
 256 end
 257
 258 function destroy_session(session)
 259         (session.log or log)("info", "Destroying "..tostring(session.direction).." session "..tostring(session.from_host).."->"..tostring(session.to_host));
 260
 261         -- FIXME: Flush sendq here/report errors to originators
 262
 263         if session.direction == "outgoing" then
 264                 hosts[session.from_host].s2sout[session.to_host] = nil;
 265         end
 266
 267         for k in pairs(session) do
 268                 if k ~= "trace" then
 269                         session[k] = nil;
 270                 end
 271         end
 272 end
 273
 274 return _M;