diff options
Diffstat (limited to 'plugins/mod_s2s/s2sout.lib.lua')
| -rw-r--r-- | plugins/mod_s2s/s2sout.lib.lua | 352 |
1 files changed, 352 insertions, 0 deletions
diff --git a/plugins/mod_s2s/s2sout.lib.lua b/plugins/mod_s2s/s2sout.lib.lua new file mode 100644 index 00000000..ec8ea4d4 --- /dev/null +++ b/plugins/mod_s2s/s2sout.lib.lua @@ -0,0 +1,352 @@ +-- Prosody IM +-- Copyright (C) 2008-2010 Matthew Wild +-- Copyright (C) 2008-2010 Waqas Hussain +-- +-- This project is MIT/X11 licensed. Please see the +-- COPYING file in the source package for more information. +-- + +--- Module containing all the logic for connecting to a remote server + +local portmanager = require "core.portmanager"; +local wrapclient = require "net.server".wrapclient; +local initialize_filters = require "util.filters".initialize; +local idna_to_ascii = require "util.encodings".idna.to_ascii; +local new_ip = require "util.ip".new_ip; +local rfc6724_dest = require "util.rfc6724".destination; +local socket = require "socket"; +local adns = require "net.adns"; +local dns = require "net.dns"; +local t_insert, t_sort, ipairs = table.insert, table.sort, ipairs; +local local_addresses = require "util.net".local_addresses; + +local s2s_destroy_session = require "core.s2smanager".destroy_session; + +local log = module._log; + +local sources = {}; +local has_ipv4, has_ipv6; + +local dns_timeout = module:get_option_number("dns_timeout", 15); +dns.settimeout(dns_timeout); +local max_dns_depth = module:get_option_number("dns_max_depth", 3); + +local s2sout = {}; + +local s2s_listener; + + +function s2sout.set_listener(listener) + s2s_listener = listener; +end + +local function compare_srv_priorities(a,b) + return a.priority < b.priority or (a.priority == b.priority and a.weight > b.weight); +end + +function s2sout.initiate_connection(host_session) + initialize_filters(host_session); + host_session.version = 1; + + -- Kick the connection attempting machine into life + if not s2sout.attempt_connection(host_session) then + -- Intentionally not returning here, the + -- session is needed, connected or not + s2s_destroy_session(host_session); + end + + if not host_session.sends2s then + -- A sends2s which buffers data (until the stream is opened) + -- note that data in this buffer will be sent before the stream is authed + -- and will not be ack'd in any way, successful or otherwise + local buffer; + function host_session.sends2s(data) + if not buffer then + buffer = {}; + host_session.send_buffer = buffer; + end + log("debug", "Buffering data on unconnected s2sout to %s", tostring(host_session.to_host)); + buffer[#buffer+1] = data; + log("debug", "Buffered item %d: %s", #buffer, tostring(data)); + end + end +end + +function s2sout.attempt_connection(host_session, err) + local to_host = host_session.to_host; + local connect_host, connect_port = to_host and idna_to_ascii(to_host), 5269; + + if not connect_host then + return false; + end + + if not err then -- This is our first attempt + log("debug", "First attempt to connect to %s, starting with SRV lookup...", to_host); + host_session.connecting = true; + local handle; + handle = adns.lookup(function (answer) + handle = nil; + host_session.connecting = nil; + if answer and #answer > 0 then + log("debug", "%s has SRV records, handling...", to_host); + local srv_hosts = { answer = answer }; + host_session.srv_hosts = srv_hosts; + for _, record in ipairs(answer) do + t_insert(srv_hosts, record.srv); + end + if #srv_hosts == 1 and srv_hosts[1].target == "." then + log("debug", "%s does not provide a XMPP service", to_host); + s2s_destroy_session(host_session, err); -- Nothing to see here + return; + end + t_sort(srv_hosts, compare_srv_priorities); + + local srv_choice = srv_hosts[1]; + host_session.srv_choice = 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 + else + log("debug", "%s has no SRV records, falling back to A/AAAA", to_host); + end + -- Try with SRV, or just the plain hostname if no SRV + local ok, err = s2sout.try_connect(host_session, connect_host, connect_port); + if not ok then + if not s2sout.attempt_connection(host_session, err) then + -- No more attempts will be made + s2s_destroy_session(host_session, err); + end + end + end, "_xmpp-server._tcp."..connect_host..".", "SRV"); + + return true; -- Attempt in progress + elseif host_session.ip_hosts then + return s2sout.try_connect(host_session, connect_host, connect_port, err); + elseif host_session.srv_hosts and #host_session.srv_hosts > host_session.srv_choice then -- Not our first attempt, and we also have SRV + host_session.srv_choice = host_session.srv_choice + 1; + local srv_choice = host_session.srv_hosts[host_session.srv_choice]; + connect_host, connect_port = srv_choice.target or to_host, srv_choice.port or connect_port; + host_session.log("info", "Connection failed (%s). Attempt #%d: This time to %s:%d", tostring(err), host_session.srv_choice, connect_host, connect_port); + else + host_session.log("info", "Failed in all attempts to connect to %s", tostring(host_session.to_host)); + -- We're out of options + return false; + end + + if not (connect_host and connect_port) then + -- Likely we couldn't resolve DNS + 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)); + return false; + end + + return s2sout.try_connect(host_session, connect_host, connect_port); +end + +function s2sout.try_next_ip(host_session) + host_session.connecting = nil; + host_session.ip_choice = host_session.ip_choice + 1; + local ip = host_session.ip_hosts[host_session.ip_choice]; + local ok, err= s2sout.make_connect(host_session, ip.ip, ip.port); + if not ok then + if not s2sout.attempt_connection(host_session, err or "closed") then + err = err and (": "..err) or ""; + s2s_destroy_session(host_session, "Connection failed"..err); + end + end +end + +function s2sout.try_connect(host_session, connect_host, connect_port, err) + host_session.connecting = true; + + if not err then + local IPs = {}; + host_session.ip_hosts = IPs; + local handle4, handle6; + local have_other_result = not(has_ipv4) or not(has_ipv6) or false; + + if has_ipv4 then + handle4 = adns.lookup(function (reply, err) + handle4 = nil; + + -- COMPAT: This is a compromise for all you CNAME-(ab)users :) + if not (reply and reply[#reply] and reply[#reply].a) then + local count = max_dns_depth; + reply = dns.peek(connect_host, "CNAME", "IN"); + while count > 0 and reply and reply[#reply] and not reply[#reply].a and reply[#reply].cname do + log("debug", "Looking up %s (DNS depth is %d)", tostring(reply[#reply].cname), count); + reply = dns.peek(reply[#reply].cname, "A", "IN") or dns.peek(reply[#reply].cname, "CNAME", "IN"); + count = count - 1; + end + end + -- end of CNAME resolving + + if reply and reply[#reply] and reply[#reply].a then + for _, ip in ipairs(reply) do + log("debug", "DNS reply for %s gives us %s", connect_host, ip.a); + IPs[#IPs+1] = new_ip(ip.a, "IPv4"); + end + end + + if have_other_result then + if #IPs > 0 then + rfc6724_dest(host_session.ip_hosts, sources); + for i = 1, #IPs do + IPs[i] = {ip = IPs[i], port = connect_port}; + end + host_session.ip_choice = 0; + s2sout.try_next_ip(host_session); + else + log("debug", "DNS lookup failed to get a response for %s", connect_host); + host_session.ip_hosts = nil; + if not s2sout.attempt_connection(host_session, "name resolution failed") then -- Retry if we can + log("debug", "No other records to try for %s - destroying", host_session.to_host); + err = err and (": "..err) or ""; + s2s_destroy_session(host_session, "DNS resolution failed"..err); -- End of the line, we can't + end + end + else + have_other_result = true; + end + end, connect_host, "A", "IN"); + else + have_other_result = true; + end + + if has_ipv6 then + handle6 = adns.lookup(function (reply, err) + handle6 = nil; + + if reply and reply[#reply] and reply[#reply].aaaa then + for _, ip in ipairs(reply) do + log("debug", "DNS reply for %s gives us %s", connect_host, ip.aaaa); + IPs[#IPs+1] = new_ip(ip.aaaa, "IPv6"); + end + end + + if have_other_result then + if #IPs > 0 then + rfc6724_dest(host_session.ip_hosts, sources); + for i = 1, #IPs do + IPs[i] = {ip = IPs[i], port = connect_port}; + end + host_session.ip_choice = 0; + s2sout.try_next_ip(host_session); + else + log("debug", "DNS lookup failed to get a response for %s", connect_host); + host_session.ip_hosts = nil; + if not s2sout.attempt_connection(host_session, "name resolution failed") then -- Retry if we can + log("debug", "No other records to try for %s - destroying", host_session.to_host); + err = err and (": "..err) or ""; + s2s_destroy_session(host_session, "DNS resolution failed"..err); -- End of the line, we can't + end + end + else + have_other_result = true; + end + end, connect_host, "AAAA", "IN"); + else + have_other_result = true; + end + return true; + 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 + s2sout.try_next_ip(host_session); + else + host_session.ip_hosts = nil; + if not s2sout.attempt_connection(host_session, "out of IP addresses") then -- Retry if we can + log("debug", "No other records to try for %s - destroying", host_session.to_host); + err = err and (": "..err) or ""; + s2s_destroy_session(host_session, "Connecting failed"..err); -- End of the line, we can't + return false; + end + end + + return true; +end + +function s2sout.make_connect(host_session, connect_host, connect_port) + (host_session.log or log)("debug", "Beginning new connection attempt to %s ([%s]:%d)", host_session.to_host, connect_host.addr, connect_port); + + -- Reset secure flag in case this is another + -- connection attempt after a failed STARTTLS + host_session.secure = nil; + + local conn, handler; + local proto = connect_host.proto; + if proto == "IPv4" then + conn, handler = socket.tcp(); + elseif proto == "IPv6" and socket.tcp6 then + conn, handler = socket.tcp6(); + else + handler = "Unsupported protocol: "..tostring(proto); + end + + if not conn then + log("warn", "Failed to create outgoing connection, system error: %s", handler); + return false, handler; + end + + conn:settimeout(0); + local success, err = conn:connect(connect_host.addr, connect_port); + if not success and err ~= "timeout" then + log("warn", "s2s connect() to %s (%s:%d) failed: %s", host_session.to_host, connect_host.addr, connect_port, err); + return false, err; + end + + conn = wrapclient(conn, connect_host.addr, connect_port, s2s_listener, "*a"); + host_session.conn = conn; + + local filter = initialize_filters(host_session); + local w, log = conn.write, host_session.log; + host_session.sends2s = function (t) + log("debug", "sending: %s", (t.top_tag and t:top_tag()) or t:match("^[^>]*>?")); + if t.name then + t = filter("stanzas/out", t); + end + if t then + t = filter("bytes/out", tostring(t)); + if t then + return w(conn, tostring(t)); + end + end + end + + -- Register this outgoing connection so that xmppserver_listener knows about it + -- otherwise it will assume it is a new incoming connection + s2s_listener.register_outgoing(conn, host_session); + + log("debug", "Connection attempt in progress..."); + return true; +end + +module:hook_global("service-added", function (event) + if event.name ~= "s2s" then return end + + local s2s_sources = portmanager.get_active_services():get("s2s"); + if not s2s_sources then + module:log("warn", "s2s not listening on any ports, outgoing connections may fail"); + return; + end + for source, _ in pairs(s2s_sources) do + if source == "*" or source == "0.0.0.0" then + for _, addr in ipairs(local_addresses("ipv4", true)) do + sources[#sources + 1] = new_ip(addr, "IPv4"); + end + elseif source == "::" then + for _, addr in ipairs(local_addresses("ipv6", true)) do + sources[#sources + 1] = new_ip(addr, "IPv6"); + end + else + sources[#sources + 1] = new_ip(source, (source:find(":") and "IPv6") or "IPv4"); + end + end + for i = 1,#sources do + if sources[i].proto == "IPv6" then + has_ipv6 = true; + elseif sources[i].proto == "IPv4" then + has_ipv4 = true; + end + end +end); + +return s2sout; |