-- 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.

--

local config = require "core.configmanager";

local create_context = require "core.certmanager".create_context;

local st = require "util.stanza";

local c2s_require_encryption = module:get_option("c2s_require_encryption") or module:get_option("require_encryption");

local s2s_require_encryption = module:get_option("s2s_require_encryption");

local allow_s2s_tls = module:get_option("s2s_allow_encryption") ~= false;

local s2s_secure_auth = module:get_option("s2s_secure_auth");

if s2s_secure_auth and s2s_require_encryption == false then

	module:log("warn", "s2s_secure_auth implies s2s_require_encryption, but s2s_require_encryption is set to false");

	s2s_require_encryption = true;

end

local xmlns_starttls = 'urn:ietf:params:xml:ns:xmpp-tls';

local starttls_attr = { xmlns = xmlns_starttls };

local starttls_proceed = st.stanza("proceed", starttls_attr);

local starttls_failure = st.stanza("failure", starttls_attr);

local c2s_feature = st.stanza("starttls", starttls_attr);

local s2s_feature = st.stanza("starttls", starttls_attr);

if c2s_require_encryption then c2s_feature:tag("required"):up(); end

if s2s_require_encryption then s2s_feature:tag("required"):up(); end

local hosts = prosody.hosts;

local host = hosts[module.host];

local ssl_ctx_c2s, ssl_ctx_s2sout, ssl_ctx_s2sin;

do

	local function get_ssl_cfg(typ)

		local cfg_key = (typ and typ.."_" or "").."ssl";

		local ssl_config = config.rawget(module.host, cfg_key);

		if not ssl_config then

			local base_host = module.host:match("%.(.*)");

			ssl_config = config.get(base_host, cfg_key);

		end

		return ssl_config or typ and get_ssl_cfg();

	end

	local ssl_config, err = get_ssl_cfg("c2s");

	ssl_ctx_c2s, err = create_context(host.host, "server", ssl_config); -- for incoming client connections

	if err then module:log("error", "Error creating context for c2s: %s", err); end

	ssl_config = get_ssl_cfg("s2s");

	ssl_ctx_s2sin, err = create_context(host.host, "server", ssl_config); -- for incoming server connections

	ssl_ctx_s2sout = create_context(host.host, "client", ssl_config); -- for outgoing server connections

	if err then module:log("error", "Error creating context for s2s: %s", err); end -- Both would have the same issue

end

local function can_do_tls(session)

	if not session.conn.starttls then

		return false;

	elseif session.ssl_ctx then

		return true;

	end

	if session.type == "c2s_unauthed" then

		session.ssl_ctx = ssl_ctx_c2s;

	elseif session.type == "s2sin_unauthed" and allow_s2s_tls then

		session.ssl_ctx = ssl_ctx_s2sin;

	elseif session.direction == "outgoing" and allow_s2s_tls then

		session.ssl_ctx = ssl_ctx_s2sout;

	else

		return false;

	end

	return session.ssl_ctx;

end

-- Hook <starttls/>

module:hook("stanza/urn:ietf:params:xml:ns:xmpp-tls:starttls", function(event)

	local origin = event.origin;

	if can_do_tls(origin) then

		(origin.sends2s or origin.send)(starttls_proceed);

		origin:reset_stream();

		origin.conn:starttls(origin.ssl_ctx);

		origin.log("debug", "TLS negotiation started for %s...", origin.type);

		origin.secure = false;

	else

		origin.log("warn", "Attempt to start TLS, but TLS is not available on this %s connection", origin.type);

		(origin.sends2s or origin.send)(starttls_failure);

		origin:close();

	end

	return true;

end);

-- Advertize stream feature

module:hook("stream-features", function(event)

	local origin, features = event.origin, event.features;

	if can_do_tls(origin) then

		features:add_child(c2s_feature);

	end

end);

module:hook("s2s-stream-features", function(event)

	local origin, features = event.origin, event.features;

	if can_do_tls(origin) then

		features:add_child(s2s_feature);

	end

end);

-- For s2sout connections, start TLS if we can

module:hook_stanza("http://etherx.jabber.org/streams", "features", function (session, stanza)

	module:log("debug", "Received features element");

	if can_do_tls(session) and stanza:child_with_ns(xmlns_starttls) then

		module:log("debug", "%s is offering TLS, taking up the offer...", session.to_host);

		session.sends2s("<starttls xmlns='"..xmlns_starttls.."'/>");

		return true;

	end

end, 500);

module:hook_stanza(xmlns_starttls, "proceed", function (session, stanza)

	module:log("debug", "Proceeding with TLS on s2sout...");

	session:reset_stream();

	session.conn:starttls(session.ssl_ctx);

	session.secure = false;

	return true;

end);