[prosody.git] / core / s2smanager.lua

local hosts = hosts;
local sessions = sessions;
local socket = require "socket";
local format = string.format;
local t_insert, t_sort = table.insert, table.sort;
local get_traceback = debug.traceback;
local tostring, pairs, ipairs, getmetatable, print, newproxy, error, tonumber
    = tostring, pairs, ipairs, getmetatable, print, newproxy, error, tonumber;

local connlisteners_get = require "net.connlisteners".get;
local wraptlsclient = require "net.server".wraptlsclient;
local modulemanager = require "core.modulemanager";
local st = require "stanza";
local stanza = st.stanza;

local uuid_gen = require "util.uuid".generate;

local logger_init = require "util.logger".init;

local log = logger_init("s2smanager");

local md5_hash = require "util.hashes".md5;

local dialback_secret = "This is very secret!!! Ha!";

local dns = require "net.dns";

module "s2smanager"

local function compare_srv_priorities(a,b) return a.priority < b.priority or a.weight < b.weight; end

function send_to_host(from_host, to_host, data)
        if data.name then data = tostring(data); end
        local host = hosts[from_host].s2sout[to_host];
        if host then
                -- We have a connection to this host already
                if host.type == "s2sout_unauthed" and ((not data.xmlns) or data.xmlns == "jabber:client" or data.xmlns == "jabber:server") then
                        (host.log or log)("debug", "trying to send over unauthed s2sout to "..to_host..", authing it now...");
                        if not host.notopen and not host.dialback_key then
                                host.log("debug", "dialback had not been initiated");
                                initiate_dialback(host);
                        end
                        
                        -- Queue stanza until we are able to send it
                        if host.sendq then t_insert(host.sendq, data);
                        else host.sendq = { data }; end
                elseif host.type == "local" or host.type == "component" then
                        log("error", "Trying to send a stanza to ourselves??")
                        log("error", "Traceback: %s", get_traceback());
                        log("error", "Stanza: %s", tostring(data));
                else
                        (host.log or log)("debug", "going to send stanza to "..to_host.." from "..from_host);
                        -- FIXME
                        if host.from_host ~= from_host then
                                log("error", "WARNING! This might, possibly, be a bug, but it might not...");
                                log("error", "We are going to send from %s instead of %s", tostring(host.from_host), tostring(from_host));
                        end
                        host.sends2s(data);
                        host.log("debug", "stanza sent over "..host.type);
                end
        else
                log("debug", "opening a new outgoing connection for this stanza");
                local host_session = new_outgoing(from_host, to_host);
                -- Store in buffer
                host_session.sendq = { data };
        end
end

local open_sessions = 0;

function new_incoming(conn)
        local session = { conn = conn, type = "s2sin_unauthed", direction = "incoming" };
        if true then
                session.trace = newproxy(true);
                getmetatable(session.trace).__gc = function () open_sessions = open_sessions - 1; print("s2s session got collected, now "..open_sessions.." s2s sessions are allocated") end;
        end
        open_sessions = open_sessions + 1;
        local w, log = conn.write, logger_init("s2sin"..tostring(conn):match("[a-f0-9]+$"));
        session.sends2s = function (t) log("debug", "sending: %s", tostring(t)); w(tostring(t)); end
        return session;
end

function new_outgoing(from_host, to_host)
                local host_session = { to_host = to_host, from_host = from_host, notopen = true, type = "s2sout_unauthed", direction = "outgoing" };
                hosts[from_host].s2sout[to_host] = host_session;
                local cl = connlisteners_get("xmppserver");
                
                local conn, handler = socket.tcp()
                
                --FIXME: Below parameters (ports/ip) are incorrect (use SRV)
                
                local connect_host, connect_port = to_host, 5269;
                
                local answer = dns.lookup("_xmpp-server._tcp."..to_host..".", "SRV");
                
                if answer then
                        log("debug", to_host.." has SRV records, handling...");
                        local srv_hosts = {};
                        host_session.srv_hosts = srv_hosts;
                        for _, record in ipairs(answer) do
                                t_insert(srv_hosts, record.srv);
                        end
                        t_sort(srv_hosts, compare_srv_priorities);
                        
                        local srv_choice = srv_hosts[1];
                        if srv_choice then
                                connect_host, connect_port = srv_choice.target or to_host, srv_choice.port or connect_port;
                                log("debug", "Best record found, will connect to %s:%d", connect_host, connect_port);
                        end
                end
                
                conn:settimeout(0);
                local success, err = conn:connect(connect_host, connect_port);
                if not success and err ~= "timeout" then
                        log("warn", "s2s connect() failed: %s", err);
                end
                
                conn = wraptlsclient(cl, conn, connect_host, connect_port, 0, 1, hosts[from_host].ssl_ctx );
                host_session.conn = conn;
                
                -- Register this outgoing connection so that xmppserver_listener knows about it
                -- otherwise it will assume it is a new incoming connection
                cl.register_outgoing(conn, host_session);
                
                local log;
                do
                        local conn_name = "s2sout"..tostring(conn):match("[a-f0-9]*$");
                        log = logger_init(conn_name);
                        host_session.log = log;
                end
                
                local w = conn.write;
                host_session.sends2s = function (t) log("debug", "sending: %s", tostring(t)); w(tostring(t)); end
                
                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));
                 
                return host_session;
end

function streamopened(session, attr)
        local send = session.sends2s;
        
        session.version = tonumber(attr.version) or 0;
        if session.version >= 1.0 and not (attr.to and attr.from) then
                print("to: "..tostring(attr.to).." from: "..tostring(attr.from));
                log("warn", (session.to_host or "(unknown)").." failed to specify 'to' or 'from' hostname as per RFC");
        end
        
        if session.direction == "incoming" then
                -- Send a reply stream header
                
                for k,v in pairs(attr) do print("", tostring(k), ":::", tostring(v)); end
                
                session.to_host = attr.to;
                session.from_host = attr.from;
        
                session.streamid = uuid_gen();
                print(session, session.from_host, "incoming s2s stream opened");
                send("<?xml version='1.0'?>");
                send(stanza("stream:stream", { version = '1.0', xmlns='jabber:server', ["xmlns:db"]='jabber:server:dialback', ["xmlns:stream"]='http://etherx.jabber.org/streams', id=session.streamid, from=session.to_host }):top_tag());
                if session.to_host and not hosts[session.to_host] then
                        -- Attempting to connect to a host we don't serve
                        session:close("host-unknown");
                        return;
                end
                if session.version >= 1.0 then
                        send(st.stanza("stream:features")
                                        :tag("dialback", { xmlns='urn:xmpp:features:dialback' }):tag("optional"):up():up());
                end
        elseif session.direction == "outgoing" then
                -- If we are just using the connection for verifying dialback keys, we won't try and auth it
                if not attr.id then error("stream response did not give us a streamid!!!"); end
                session.streamid = attr.id;
        
                if not session.dialback_verifying then
                        initiate_dialback(session);
                else
                        mark_connected(session);
                end
        end

        session.notopen = nil;
end

function initiate_dialback(session)
        -- generate dialback key
        session.dialback_key = generate_dialback(session.streamid, session.to_host, session.from_host);
        session.sends2s(format("<db:result from='%s' to='%s'>%s</db:result>", session.from_host, session.to_host, session.dialback_key));
        session.log("info", "sent dialback key on outgoing s2s stream");
end

function generate_dialback(id, to, from)
        return md5_hash(id..to..from..dialback_secret); -- FIXME: See XEP-185 and XEP-220
end

function verify_dialback(id, to, from, key)
        return key == generate_dialback(id, to, from);
end

function make_authenticated(session)
        if session.type == "s2sout_unauthed" then
                session.type = "s2sout";
        elseif session.type == "s2sin_unauthed" then
                session.type = "s2sin";
        else
                return false;
        end
        session.log("info", "connection is now authenticated");
        
        mark_connected(session);
        
        return true;
end

function mark_connected(session)
        local sendq, send = session.sendq, session.sends2s;
        
        local from, to = session.from_host, session.to_host;
        
        session.log("debug", session.direction.." s2s connection "..from.."->"..to.." is now complete");
        
        local send_to_host = send_to_host;
        function session.send(data) send_to_host(to, from, data); end
        
        
        if session.direction == "outgoing" then
                if sendq then
                        session.log("debug", "sending "..#sendq.." queued stanzas across new outgoing connection to "..session.to_host);
                        for i, data in ipairs(sendq) do
                                send(data);
                                sendq[i] = nil;
                        end
                        session.sendq = nil;
                end
        end
end

function destroy_session(session)
        (session.log or log)("info", "Destroying "..tostring(session.direction).." session "..tostring(session.from_host).."->"..tostring(session.to_host));
        
        -- FIXME: Flush sendq here/report errors to originators
        
        if session.direction == "outgoing" then
                hosts[session.from_host].s2sout[session.to_host] = nil;
        end
        
        for k in pairs(session) do
                if k ~= "trace" then
                        session[k] = nil;
                end
        end
end

return _M;