-- (C) 2011, Marco Cirillo (LW.Org)

-- Block or restrict by blacklist remote access to local components or hosts.

module:set_global()

local guard_blockall = module:get_option_set("host_guard_blockall", {})

local guard_ball_wl = module:get_option_set("host_guard_blockall_exceptions", {})

local guard_protect = module:get_option_set("host_guard_selective", {})

local guard_block_bl = module:get_option_set("host_guard_blacklist", {})

local config = require "core.configmanager"

local error_reply = require "util.stanza".error_reply

local function s2s_hook (event)

	local origin, stanza = event.session or event.origin, event.stanza or false

	local to_host, from_host = (not stanza and origin.to_host) or stanza.attr.to, (not stanza and origin.from_host) or stanza.attr.from

	if origin.type == "s2sin" or origin.type == "s2sin_unauthed" then

	   if guard_blockall:contains(to_host) and not guard_ball_wl:contains(from_host) or

	      guard_block_bl:contains(from_host) and guard_protect:contains(to_host) then

                module:log("error", "remote service %s attempted to access restricted host %s", from_host, to_host)

                origin:close({condition = "policy-violation", text = "You're not authorized, good bye."})

                return false

           end

        end

	return nil

end

local function rr_hook (event)

	local from_host, to_host, send, stanza = event.from_host, event.to_host, (event.origin and event.origin.send) or function() end, event.stanza

	if guard_blockall:contains(from_host) and not guard_ball_wl:contains(to_host) or

	   guard_block_bl:contains(to_host) and guard_protect:contains(from_host) then

	     module:log("info", "attempted to connect to a filtered remote host %s", to_host)

	     if stanza.attr.type ~= "error" then send(error_reply(event.stanza, "cancel", "policy-violation", "Communicating with a filtered remote server is not allowed.")) end

	     return true

	end

	return nil

end

local function handle_activation (host)

	if guard_blockall:contains(host) or guard_protect:contains(host) then

		if hosts[host] and hosts[host].events then

			hosts[host].events.add_handler("s2sin-established", s2s_hook, 500)

			hosts[host].events.add_handler("route/remote", rr_hook, 500)

			hosts[host].events.add_handler("stanza/jabber:server:dialback:result", s2s_hook, 500)

                	module:log ("debug", "adding host protection for: "..host)

		end

	end

end

local function handle_deactivation (host)

	if guard_blockall:contains(host) or guard_protect:contains(host) then

		if hosts[host] and hosts[host].events then

			hosts[host].events.remove_handler("s2sin-established", s2s_hook)

			hosts[host].events.remove_handler("route/remote", rr_hook)

			hosts[host].events.remove_handler("stanza/jabber:server:dialback:result", s2s_hook)

                	module:log ("debug", "removing host protection for: "..host)

		end

	end

end

local function init_hosts()

	for n,table in pairs(hosts) do

		hosts[n].events.remove_handler("s2sin-established", s2s_hook)

		hosts[n].events.remove_handler("route/remote", rr_hook)

		hosts[n].events.remove_handler("stanza/jabber:server:dialback:result", s2s_hook)

		if guard_blockall:contains(n) or guard_protect:contains(n) then	handle_activation(n) end

	end

end

local function reload()

	module:log ("debug", "server configuration reloaded, rehashing plugin tables...")

	guard_blockall = module:get_option_set("host_guard_blockall", {})

	guard_ball_wl = module:get_option_set("host_guard_blockall_exceptions", {})

	guard_protect = module:get_option_set("host_guard_selective", {})

	guard_block_bl = module:get_option_set("host_guard_blacklist", {})

	init_hosts()

end

local function setup()

        module:log ("debug", "initializing host guard module...")

        module:hook ("host-activated", handle_activation)

        module:hook ("host-deactivated", handle_deactivation)

        module:hook ("config-reloaded", reload)

        init_hosts()

end

if prosody.start_time then

	setup()

else

	module:hook ("server-started", setup)

end