Changeset

--- a/mod_smacks/README.md	Wed Oct 23 14:55:17 2024 +0200
+++ b/mod_smacks/README.md	Sun Oct 27 13:14:25 2024 +0100
@@ -6,84 +6,3 @@
 ...
 
 Since Prosody 0.12, this module is [included in Prosody](https://prosody.im/doc/modules/mod_smacks).
-
-#Introduction
-
-By default XMPP is as reliable as your network is. Unfortunately in some
-cases that is not very reliable - in some network conditions disconnects
-can be frequent and message loss can occur.
-
-To overcome this, XMPP has an optional extension (XEP-0198: Stream
-Management) which, when supported by both the client and server, can
-allow a client to resume a disconnected session, and prevent message
-loss.
-
-#Details
-
-When using XEP-0198 both the client and the server keep a queue of the
-most recently sent stanzas - this is cleared when the other end
-acknowledges they have received the stanzas. If the client disconnects,
-instead of marking the user offline the server pretends the client is
-still online for a short (configurable) period of time. If the client
-reconnects within this period, any stanzas in the queue that the client
-did not receive are re-sent.
-
-If the client fails to reconnect before the timeout it will be marked as
-offline like prosody does on disconnect without mod_smacks.
-If the client is the last one for this jid, all message stanzas are added to
-the offline store and all other stanzas stanzas are returned with an
-"recipient-unavailable" error. If the client is not the last one with an
-open smacks session, *all* stanzas are returned with an "recipient-unavailable" error.
-
-If you deliberately disabled [mod_offline], all message stanzas of the last client
-are also returned with an "recipient-unavailable" error, because the can not be
-added to the offline storage.
-If you don't want this behaviour you can use [mod_nooffline_noerror] to suppress the error.
-This is generally only advisable, if you are sure that all your clients are using MAM!
-
-This module also provides some events used by [mod_cloud_notify].
-These events are: "smacks-ack-delayed", "smacks-hibernation-start" and
-"smacks-hibernation-end". See [mod_cloud_notify] for details on how this
-events are used there.
-
-Use prosody 0.10+ to have per user limits on allowed sessions in hibernation
-state and allowed sessions for which the h-value is kept even after the
-hibernation timed out.
-These are settable using `smacks_max_hibernated_sessions` and `smacks_max_old_sessions`.
-
-#Configuration
-
-  Option                              Default           Description
-  ----------------------------------  ----------------- ------------------------------------------------------------------------------------------------------------------
-  `smacks_hibernation_time`           600 (10 minutes)  The number of seconds a disconnected session should stay alive for (to allow reconnect)
-  `smacks_enabled_s2s`                true              Enable Stream Management on server connections? *Experimental*
-  `smacks_s2s_resend`                 false             Attempt to re-send unacked messages on s2s disconnect *Experimental*
-  `smacks_max_unacked_stanzas`        0                 How many stanzas to send before requesting acknowledgement
-  `smacks_max_ack_delay`              30 (1/2 minute)   The number of seconds an ack must be unanswered to trigger an "smacks-ack-delayed" event
-  `smacks_max_hibernated_sessions`    10                The number of allowed sessions in hibernated state (limited per user)
-  `smacks_max_old_sessions`           10                The number of allowed sessions with timed out hibernation for which the h-value is still kept (limited per user)
-
-#Compatibility
-
-  ------- -------
-  trunk   Works
-  0.11    Works
-  ------- -------
-
-
-#Clients
-
-Clients that support [XEP-0198]:
-
--   Gajim (Linux, Windows, OS X)
--   Conversations (Android)
--   ChatSecure (iOS)
--   Swift (but not resumption, as of version 2.0 and alphas of 3.0)
--   Psi (in an unreleased branch)
--   Yaxim (Android)
--   Monal (iOS)
-
-[7693724881b3]: //hg.prosody.im/prosody-modules/raw-file/7693724881b3/mod_smacks/mod_smacks.lua
-[mod_offline]: //modules.prosody.im/mod_offline
-[mod_nooffline_noerror]: //modules.prosody.im/mod_nooffline_noerror
-[mod_cloud_notify]: //modules.prosody.im/mod_cloud_notify

--- a/mod_smacks/mod_smacks.lua	Wed Oct 23 14:55:17 2024 +0200
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,690 +0,0 @@
--- XEP-0198: Stream Management for Prosody IM
---
--- Copyright (C) 2010-2015 Matthew Wild
--- Copyright (C) 2010 Waqas Hussain
--- Copyright (C) 2012-2021 Kim Alvefur
--- Copyright (C) 2012 Thijs Alkemade
--- Copyright (C) 2014 Florian Zeitz
--- Copyright (C) 2016-2020 Thilo Molitor
---
--- This project is MIT/X11 licensed. Please see the
--- COPYING file in the source package for more information.
---
-
-local st = require "util.stanza";
-local dep = require "util.dependencies";
-local cache = dep.softreq("util.cache");	-- only available in prosody 0.10+
-local uuid_generate = require "util.uuid".generate;
-local jid = require "util.jid";
-
-local t_remove = table.remove;
-local math_min = math.min;
-local math_max = math.max;
-local os_time = os.time;
-local tonumber, tostring = tonumber, tostring;
-local add_filter = require "util.filters".add_filter;
-local timer = require "util.timer";
-local datetime = require "util.datetime";
-
-local xmlns_mam2 = "urn:xmpp:mam:2";
-local xmlns_sm2 = "urn:xmpp:sm:2";
-local xmlns_sm3 = "urn:xmpp:sm:3";
-local xmlns_errors = "urn:ietf:params:xml:ns:xmpp-stanzas";
-local xmlns_delay = "urn:xmpp:delay";
-
-local sm2_attr = { xmlns = xmlns_sm2 };
-local sm3_attr = { xmlns = xmlns_sm3 };
-
-local resume_timeout = module:get_option_number("smacks_hibernation_time", 600);
-local s2s_smacks = module:get_option_boolean("smacks_enabled_s2s", true);
-local s2s_resend = module:get_option_boolean("smacks_s2s_resend", false);
-local max_unacked_stanzas = module:get_option_number("smacks_max_unacked_stanzas", 0);
-local max_inactive_unacked_stanzas = module:get_option_number("smacks_max_inactive_unacked_stanzas", 256);
-local delayed_ack_timeout = module:get_option_number("smacks_max_ack_delay", 30);
-local max_hibernated_sessions = module:get_option_number("smacks_max_hibernated_sessions", 10);
-local max_old_sessions = module:get_option_number("smacks_max_old_sessions", 10);
-local core_process_stanza = prosody.core_process_stanza;
-local sessionmanager = require"core.sessionmanager";
-
-assert(max_hibernated_sessions > 0, "smacks_max_hibernated_sessions must be greater than 0");
-assert(max_old_sessions > 0, "smacks_max_old_sessions must be greater than 0");
-
-local c2s_sessions = module:shared("/*/c2s/sessions");
-
-local function init_session_cache(max_entries, evict_callback)
-	-- old prosody version < 0.10 (no limiting at all!)
-	if not cache then
-		local store = {};
-		return {
-			get = function(user, key)
-				if not user then return nil; end
-				if not key then return nil; end
-				return store[key];
-			end;
-			set = function(user, key, value)
-				if not user then return nil; end
-				if not key then return nil; end
-				store[key] = value;
-			end;
-		};
-	end
-
-	-- use per user limited cache for prosody >= 0.10
-	local stores = {};
-	return {
-			get = function(user, key)
-				if not user then return nil; end
-				if not key then return nil; end
-				if not stores[user] then
-					stores[user] = cache.new(max_entries, evict_callback);
-				end
-				return stores[user]:get(key);
-			end;
-			set = function(user, key, value)
-				if not user then return nil; end
-				if not key then return nil; end
-				if not stores[user] then stores[user] = cache.new(max_entries, evict_callback); end
-				stores[user]:set(key, value);
-				-- remove empty caches completely
-				if not stores[user]:count() then stores[user] = nil; end
-			end;
-		};
-end
-local old_session_registry = init_session_cache(max_old_sessions, nil);
-local session_registry = init_session_cache(max_hibernated_sessions, function(resumption_token, session)
-	if session.destroyed then return true; end		-- destroyed session can always be removed from cache
-	session.log("warn", "User has too much hibernated sessions, removing oldest session (token: %s)", resumption_token);
-	-- store old session's h values on force delete
-	-- save only actual h value and username/host (for security)
-	old_session_registry.set(session.username, resumption_token, {
-		h = session.handled_stanza_count,
-		username = session.username,
-		host = session.host
-	});
-	return true;	-- allow session to be removed from full cache to make room for new one
-end);
-
-local function stoppable_timer(delay, callback)
-	local stopped = false;
-	local timer = module:add_timer(delay, function (t)
-		if stopped then return; end
-		return callback(t);
-	end);
-	if timer and timer.stop then return timer; end		-- new prosody api includes stop() function
-	return {
-		stop = function(self) stopped = true end;
-		timer;
-	};
-end
-
-local function delayed_ack_function(session, stanza)
-	-- fire event only if configured to do so and our session is not already hibernated or destroyed
-	if delayed_ack_timeout > 0 and session.awaiting_ack
-	and not session.hibernating and not session.destroyed then
-		session.log("debug", "Firing event 'smacks-ack-delayed', queue = %d",
-			session.outgoing_stanza_queue and #session.outgoing_stanza_queue or 0);
-		module:fire_event("smacks-ack-delayed", {origin = session, queue = session.outgoing_stanza_queue, stanza = stanza});
-	end
-	session.delayed_ack_timer = nil;
-end
-
-local function can_do_smacks(session, advertise_only)
-	if session.smacks then return false, "unexpected-request", "Stream management is already enabled"; end
-
-	local session_type = session.type;
-	if session.username then
-		if not(advertise_only) and not(session.resource) then -- Fail unless we're only advertising sm
-			return false, "unexpected-request", "Client must bind a resource before enabling stream management";
-		end
-		return true;
-	elseif s2s_smacks and (session_type == "s2sin" or session_type == "s2sout") then
-		return true;
-	end
-	return false, "service-unavailable", "Stream management is not available for this stream";
-end
-
-module:hook("stream-features",
-		function (event)
-			if can_do_smacks(event.origin, true) then
-				event.features:tag("sm", sm2_attr):tag("optional"):up():up();
-				event.features:tag("sm", sm3_attr):tag("optional"):up():up();
-			end
-		end);
-
-module:hook("s2s-stream-features",
-		function (event)
-			if can_do_smacks(event.origin, true) then
-				event.features:tag("sm", sm2_attr):tag("optional"):up():up();
-				event.features:tag("sm", sm3_attr):tag("optional"):up():up();
-			end
-		end);
-
-local function request_ack_if_needed(session, force, reason, stanza)
-	local queue = session.outgoing_stanza_queue;
-	local expected_h = session.last_acknowledged_stanza + #queue;
-	-- session.log("debug", "*** SMACKS(1) ***: awaiting_ack=%s, hibernating=%s", tostring(session.awaiting_ack), tostring(session.hibernating));
-	local max_unacked = max_unacked_stanzas;
-	if session.state == "inactive"  then
-		max_unacked = max_inactive_unacked_stanzas;
-	end
-	if session.awaiting_ack == nil and not session.hibernating then
-		-- this check of last_requested_h prevents ack-loops if missbehaving clients report wrong
-		-- stanza counts. it is set when an <r> is really sent (e.g. inside timer), preventing any
-		-- further requests until a higher h-value would be expected.
-		-- session.log("debug", "*** SMACKS(2) ***: #queue=%s, max_unacked_stanzas=%s, expected_h=%s, last_requested_h=%s", tostring(#queue), tostring(max_unacked_stanzas), tostring(expected_h), tostring(session.last_requested_h));
-		if (#queue > max_unacked and expected_h ~= session.last_requested_h) or force then
-			session.log("debug", "Queuing <r> (in a moment) from %s - #queue=%d", reason, #queue);
-			session.awaiting_ack = false;
-			session.awaiting_ack_timer = stoppable_timer(1e-06, function ()
-				-- session.log("debug", "*** SMACKS(3) ***: awaiting_ack=%s, hibernating=%s", tostring(session.awaiting_ack), tostring(session.hibernating));
-				-- only request ack if needed and our session is not already hibernated or destroyed
-				if not session.awaiting_ack and not session.hibernating and not session.destroyed then
-					session.log("debug", "Sending <r> (inside timer, before send) from %s - #queue=%d", reason, #queue);
-					(session.sends2s or session.send)(st.stanza("r", { xmlns = session.smacks }))
-					if session.destroyed then return end -- sending something can trigger destruction
-					session.awaiting_ack = true;
-					-- expected_h could be lower than this expression e.g. more stanzas added to the queue meanwhile)
-					session.last_requested_h = session.last_acknowledged_stanza + #queue;
-					session.log("debug", "Sending <r> (inside timer, after send) from %s - #queue=%d", reason, #queue);
-					if not session.delayed_ack_timer then
-						session.delayed_ack_timer = stoppable_timer(delayed_ack_timeout, function()
-							delayed_ack_function(session, nil);		-- we don't know if this is the only new stanza in the queue
-						end);
-					end
-				end
-			end);
-		end
-	end
-
-	-- Trigger "smacks-ack-delayed"-event if we added new (ackable) stanzas to the outgoing queue
-	-- and there isn't already a timer for this event running.
-	-- If we wouldn't do this, stanzas added to the queue after the first "smacks-ack-delayed"-event
-	-- would not trigger this event (again).
-	if #queue > max_unacked and session.awaiting_ack and session.delayed_ack_timer == nil then
-		session.log("debug", "Calling delayed_ack_function directly (still waiting for ack)");
-		delayed_ack_function(session, stanza);		-- this is the only new stanza in the queue --> provide it to other modules
-	end
-end
-
-local function outgoing_stanza_filter(stanza, session)
-	-- XXX: Normally you wouldn't have to check the xmlns for a stanza as it's
-	-- supposed to be nil.
-	-- However, when using mod_smacks with mod_websocket, then mod_websocket's
-	-- stanzas/out filter can get called before this one and adds the xmlns.
-	local is_stanza = stanza.attr and
-		(not stanza.attr.xmlns or stanza.attr.xmlns == 'jabber:client')
-		and not stanza.name:find":";
-
-	if is_stanza and not stanza._cached then
-		local queue = session.outgoing_stanza_queue;
-		local cached_stanza = st.clone(stanza);
-		cached_stanza._cached = true;
-
-		if cached_stanza and cached_stanza.name ~= "iq" and cached_stanza:get_child("delay", xmlns_delay) == nil then
-			cached_stanza = cached_stanza:tag("delay", {
-				xmlns = xmlns_delay,
-				from = jid.bare(session.full_jid or session.host),
-				stamp = datetime.datetime()
-			});
-		end
-
-		queue[#queue+1] = cached_stanza;
-		if session.hibernating then
-			session.log("debug", "hibernating since %s, stanza queued", datetime.datetime(session.hibernating));
-			module:fire_event("smacks-hibernation-stanza-queued", {origin = session, queue = queue, stanza = cached_stanza});
-			return nil;
-		end
-		request_ack_if_needed(session, false, "outgoing_stanza_filter", stanza);
-	end
-	return stanza;
-end
-
-local function count_incoming_stanzas(stanza, session)
-	if not stanza.attr.xmlns then
-		session.handled_stanza_count = session.handled_stanza_count + 1;
-		session.log("debug", "Handled %d incoming stanzas", session.handled_stanza_count);
-	end
-	return stanza;
-end
-
-local function wrap_session_out(session, resume)
-	if not resume then
-		session.outgoing_stanza_queue = {};
-		session.last_acknowledged_stanza = 0;
-	end
-
-	add_filter(session, "stanzas/out", outgoing_stanza_filter, -999);
-
-	local session_close = session.close;
-	function session.close(...)
-		if session.resumption_token then
-			session_registry.set(session.username, session.resumption_token, nil);
-			old_session_registry.set(session.username, session.resumption_token, nil);
-			session.resumption_token = nil;
-		end
-		-- send out last ack as per revision 1.5.2 of XEP-0198
-		if session.smacks and session.conn and session.handled_stanza_count then
-			(session.sends2s or session.send)(st.stanza("a", { xmlns = session.smacks, h = string.format("%d", session.handled_stanza_count) }));
-		end
-		return session_close(...);
-	end
-	return session;
-end
-
-local function wrap_session_in(session, resume)
-	if not resume then
-		session.handled_stanza_count = 0;
-	end
-	add_filter(session, "stanzas/in", count_incoming_stanzas, 999);
-
-	return session;
-end
-
-local function wrap_session(session, resume)
-	wrap_session_out(session, resume);
-	wrap_session_in(session, resume);
-	return session;
-end
-
-function handle_enable(session, stanza, xmlns_sm)
-	local ok, err, err_text = can_do_smacks(session);
-	if not ok then
-		session.log("warn", "Failed to enable smacks: %s", err_text); -- TODO: XEP doesn't say we can send error text, should it?
-		(session.sends2s or session.send)(st.stanza("failed", { xmlns = xmlns_sm }):tag(err, { xmlns = xmlns_errors}));
-		return true;
-	end
-
-	module:log("debug", "Enabling stream management");
-	session.smacks = xmlns_sm;
-
-	wrap_session(session, false);
-
-	local resume_token;
-	local resume = stanza.attr.resume;
-	if resume == "true" or resume == "1" then
-		resume_token = uuid_generate();
-		session_registry.set(session.username, resume_token, session);
-		session.resumption_token = resume_token;
-	end
-	(session.sends2s or session.send)(st.stanza("enabled", { xmlns = xmlns_sm, id = resume_token, resume = resume, max = tostring(resume_timeout) }));
-	return true;
-end
-module:hook_stanza(xmlns_sm2, "enable", function (session, stanza) return handle_enable(session, stanza, xmlns_sm2); end, 100);
-module:hook_stanza(xmlns_sm3, "enable", function (session, stanza) return handle_enable(session, stanza, xmlns_sm3); end, 100);
-
-module:hook_stanza("http://etherx.jabber.org/streams", "features",
-		function (session, stanza)
-			stoppable_timer(1e-6, function ()
-				if can_do_smacks(session) then
-					if stanza:get_child("sm", xmlns_sm3) then
-						session.sends2s(st.stanza("enable", sm3_attr));
-						session.smacks = xmlns_sm3;
-					elseif stanza:get_child("sm", xmlns_sm2) then
-						session.sends2s(st.stanza("enable", sm2_attr));
-						session.smacks = xmlns_sm2;
-					else
-						return;
-					end
-					wrap_session_out(session, false);
-				end
-			end);
-		end);
-
-function handle_enabled(session, stanza, xmlns_sm)
-	module:log("debug", "Enabling stream management");
-	session.smacks = xmlns_sm;
-
-	wrap_session_in(session, false);
-
-	-- FIXME Resume?
-
-	return true;
-end
-module:hook_stanza(xmlns_sm2, "enabled", function (session, stanza) return handle_enabled(session, stanza, xmlns_sm2); end, 100);
-module:hook_stanza(xmlns_sm3, "enabled", function (session, stanza) return handle_enabled(session, stanza, xmlns_sm3); end, 100);
-
-function handle_r(origin, stanza, xmlns_sm)
-	if not origin.smacks then
-		module:log("debug", "Received ack request from non-smack-enabled session");
-		return;
-	end
-	module:log("debug", "Received ack request, acking for %d", origin.handled_stanza_count);
-	-- Reply with <a>
-	(origin.sends2s or origin.send)(st.stanza("a", { xmlns = xmlns_sm, h = string.format("%d", origin.handled_stanza_count) }));
-	-- piggyback our own ack request if needed (see request_ack_if_needed() for explanation of last_requested_h)
-	local expected_h = origin.last_acknowledged_stanza + #origin.outgoing_stanza_queue;
-	if #origin.outgoing_stanza_queue > 0 and expected_h ~= origin.last_requested_h then
-		request_ack_if_needed(origin, true, "piggybacked by handle_r", nil);
-	end
-	return true;
-end
-module:hook_stanza(xmlns_sm2, "r", function (origin, stanza) return handle_r(origin, stanza, xmlns_sm2); end);
-module:hook_stanza(xmlns_sm3, "r", function (origin, stanza) return handle_r(origin, stanza, xmlns_sm3); end);
-
-function handle_a(origin, stanza)
-	if not origin.smacks then return; end
-	origin.awaiting_ack = nil;
-	if origin.awaiting_ack_timer then
-		origin.awaiting_ack_timer:stop();
-	end
-	if origin.delayed_ack_timer then
-		origin.delayed_ack_timer:stop();
-		origin.delayed_ack_timer = nil;
-	end
-	-- Remove handled stanzas from outgoing_stanza_queue
-	-- origin.log("debug", "ACK: h=%s, last=%s", stanza.attr.h or "", origin.last_acknowledged_stanza or "");
-	local h = tonumber(stanza.attr.h);
-	if not h then
-		origin:close{ condition = "invalid-xml"; text = "Missing or invalid 'h' attribute"; };
-		return;
-	end
-	local handled_stanza_count = h-origin.last_acknowledged_stanza;
-	local queue = origin.outgoing_stanza_queue;
-	if handled_stanza_count > #queue then
-		origin.log("warn", "The client says it handled %d new stanzas, but we only sent %d :)",
-			handled_stanza_count, #queue);
-		origin.log("debug", "Client h: %d, our h: %d", tonumber(stanza.attr.h), origin.last_acknowledged_stanza);
-		for i=1,#queue do
-			origin.log("debug", "Q item %d: %s", i, tostring(queue[i]));
-		end
-        origin:close{ condition = "undefined-condition"; text = "Client acknowledged more stanzas than sent by server"; };
-        return;
-	end
-
-	for i=1,math_min(handled_stanza_count,#queue) do
-		local handled_stanza = t_remove(origin.outgoing_stanza_queue, 1);
-		module:fire_event("delivery/success", { session = origin, stanza = handled_stanza });
-	end
-
-	origin.log("debug", "#queue = %d", #queue);
-	origin.last_acknowledged_stanza = origin.last_acknowledged_stanza + handled_stanza_count;
-	request_ack_if_needed(origin, false, "handle_a", nil)
-	return true;
-end
-module:hook_stanza(xmlns_sm2, "a", handle_a);
-module:hook_stanza(xmlns_sm3, "a", handle_a);
-
---TODO: Optimise... incoming stanzas should be handled by a per-session
--- function that has a counter as an upvalue (no table indexing for increments,
--- and won't slow non-198 sessions). We can also then remove the .handled flag
--- on stanzas
-
-local function handle_unacked_stanzas(session)
-	local queue = session.outgoing_stanza_queue;
-	local error_attr = { type = "cancel" };
-	if #queue > 0 then
-		session.outgoing_stanza_queue = {};
-		for i=1,#queue do
-			if not module:fire_event("delivery/failure", { session = session, stanza = queue[i] }) then
-				if queue[i].attr.type ~= "error" then
-					local reply = st.reply(queue[i]);
-					if reply.attr.to ~= session.full_jid then
-						reply.attr.type = "error";
-						reply:tag("error", error_attr)
-							:tag("recipient-unavailable", {xmlns = "urn:ietf:params:xml:ns:xmpp-stanzas"});
-						core_process_stanza(session, reply);
-					end
-				end
-			end
-		end
-	end
-end
-
--- don't send delivery errors for messages which will be delivered by mam later on
--- check if stanza was archived --> this will allow us to send back errors for stanzas not archived
--- because the user configured the server to do so ("no-archive"-setting for one special contact for example)
-local function get_stanza_id(stanza, by_jid)
-	for tag in stanza:childtags("stanza-id", "urn:xmpp:sid:0") do
-		if tag.attr.by == by_jid then
-			return tag.attr.id;
-		end
-	end
-	return nil;
-end
-module:hook("delivery/failure", function(event)
-	local session, stanza = event.session, event.stanza;
-	-- Only deal with authenticated (c2s) sessions
-	if session.username then
-		if stanza.name == "message" and stanza.attr.xmlns == nil and
-				( stanza.attr.type == "chat" or ( stanza.attr.type or "normal" ) == "normal" ) then
-			-- don't store messages in offline store if they are mam results
-			local mam_result = stanza:get_child("result", xmlns_mam2);
-			if mam_result ~= nil then
-				return true;		-- stanza already "handled", don't send an error and don't add it to offline storage
-			end
-			-- do nothing here for normal messages and don't send out "message delivery errors",
-			-- because messages are already in MAM at this point (no need to frighten users)
-			local stanza_id = get_stanza_id(stanza, jid.bare(session.full_jid));
-			if session.mam_requested and stanza_id ~= nil then
-				session.log("debug", "mod_smacks delivery/failure returning true for mam-handled stanza: mam-archive-id=%s", tostring(stanza_id));
-				return true;		-- stanza handled, don't send an error
-			end
-			-- store message in offline store, if this client does not use mam *and* was the last client online
-			local sessions = prosody.hosts[module.host].sessions[session.username] and
-					prosody.hosts[module.host].sessions[session.username].sessions or nil;
-			if sessions and next(sessions) == session.resource and next(sessions, session.resource) == nil then
-				local ok = module:fire_event("message/offline/handle", { origin = session, username = session.username, stanza = stanza });
-				session.log("debug", "mod_smacks delivery/failuere returning %s for offline-handled stanza", tostring(ok));
-				return ok;			-- if stanza was handled, don't send an error
-			end
-		end
-	end
-end);
-
-module:hook("pre-resource-unbind", function (event)
-	local session, err = event.session, event.error;
-	if session.smacks then
-		if not session.resumption_token then
-			local queue = session.outgoing_stanza_queue;
-			if #queue > 0 then
-				session.log("debug", "Destroying session with %d unacked stanzas", #queue);
-				handle_unacked_stanzas(session);
-			end
-		else
-			session.log("debug", "mod_smacks hibernating session for up to %d seconds", resume_timeout);
-			local hibernate_time = os_time(); -- Track the time we went into hibernation
-			session.hibernating = hibernate_time;
-			local resumption_token = session.resumption_token;
-			module:fire_event("smacks-hibernation-start", {origin = session, queue = session.outgoing_stanza_queue});
-			timer.add_task(resume_timeout, function ()
-				session.log("debug", "mod_smacks hibernation timeout reached...");
-				-- We need to check the current resumption token for this resource
-				-- matches the smacks session this timer is for in case it changed
-				-- (for example, the client may have bound a new resource and
-				-- started a new smacks session, or not be using smacks)
-				local curr_session = full_sessions[session.full_jid];
-				if session.destroyed then
-					session.log("debug", "The session has already been destroyed");
-				elseif curr_session and curr_session.resumption_token == resumption_token
-				-- Check the hibernate time still matches what we think it is,
-				-- otherwise the session resumed and re-hibernated.
-				and session.hibernating == hibernate_time then
-					-- wait longer if the timeout isn't reached because push was enabled for this session
-					-- session.first_hibernated_push is the starting point for hibernation timeouts of those push enabled clients
-					-- wait for an additional resume_timeout seconds if no push occurred since hibernation at all
-					local current_time = os_time();
-					local timeout_start = math_max(session.hibernating, session.first_hibernated_push or session.hibernating);
-					if session.push_identifier ~= nil and not session.first_hibernated_push then
-						session.log("debug", "No push happened since hibernation started, hibernating session for up to %d extra seconds", resume_timeout);
-						return resume_timeout;
-					end
-					if session.push_identifier ~= nil and current_time-timeout_start < resume_timeout then
-						session.log("debug", "A push happened since hibernation started, hibernating session for up to %d extra seconds", resume_timeout-(current_time-timeout_start));
-						return resume_timeout-(current_time-timeout_start);		-- time left to wait
-					end
-					session.log("debug", "Destroying session for hibernating too long");
-					session_registry.set(session.username, session.resumption_token, nil);
-					-- save only actual h value and username/host (for security)
-					old_session_registry.set(session.username, session.resumption_token, {
-						h = session.handled_stanza_count,
-						username = session.username,
-						host = session.host
-					});
-					session.resumption_token = nil;
-					sessionmanager.destroy_session(session);
-				else
-					session.log("debug", "Session resumed before hibernation timeout, all is well")
-				end
-			end);
-			return true; -- Postpone destruction for now
-		end
-	end
-end);
-
-local function handle_s2s_destroyed(event)
-	local session = event.session;
-	local queue = session.outgoing_stanza_queue;
-	if queue and #queue > 0 then
-		session.log("warn", "Destroying session with %d unacked stanzas", #queue);
-		if s2s_resend then
-			for i = 1, #queue do
-				module:send(queue[i]);
-			end
-			session.outgoing_stanza_queue = nil;
-		else
-			handle_unacked_stanzas(session);
-		end
-	end
-end
-
-module:hook("s2sout-destroyed", handle_s2s_destroyed);
-module:hook("s2sin-destroyed", handle_s2s_destroyed);
-
-local function get_session_id(session)
-	return session.id or (tostring(session):match("[a-f0-9]+$"));
-end
-
-function handle_resume(session, stanza, xmlns_sm)
-	if session.full_jid then
-		session.log("warn", "Tried to resume after resource binding");
-		session.send(st.stanza("failed", { xmlns = xmlns_sm })
-			:tag("unexpected-request", { xmlns = xmlns_errors })
-		);
-		return true;
-	end
-
-	local id = stanza.attr.previd;
-	local original_session = session_registry.get(session.username, id);
-	if not original_session then
-		session.log("debug", "Tried to resume non-existent session with id %s", id);
-		local old_session = old_session_registry.get(session.username, id);
-		if old_session and session.username == old_session.username
-		and session.host == old_session.host
-		and old_session.h then
-			session.send(st.stanza("failed", { xmlns = xmlns_sm, h = string.format("%d", old_session.h) })
-				:tag("item-not-found", { xmlns = xmlns_errors })
-			);
-		else
-			session.send(st.stanza("failed", { xmlns = xmlns_sm })
-				:tag("item-not-found", { xmlns = xmlns_errors })
-			);
-		end;
-	elseif session.username == original_session.username
-	and session.host == original_session.host then
-		session.log("debug", "mod_smacks resuming existing session %s...", get_session_id(original_session));
-		original_session.log("debug", "mod_smacks session resumed from %s...", get_session_id(session));
-		-- TODO: All this should move to sessionmanager (e.g. session:replace(new_session))
-		if original_session.conn then
-			original_session.log("debug", "mod_smacks closing an old connection for this session");
-			local conn = original_session.conn;
-			c2s_sessions[conn] = nil;
-			conn:close();
-		end
-		local migrated_session_log = session.log;
-		original_session.ip = session.ip;
-		original_session.conn = session.conn;
-		original_session.send = session.send;
-		original_session.close = session.close;
-		original_session.filter = session.filter;
-		original_session.filter.session = original_session;
-		original_session.filters = session.filters;
-		original_session.stream = session.stream;
-		original_session.secure = session.secure;
-		original_session.hibernating = nil;
-		session.log = original_session.log;
-		session.type = original_session.type;
-		wrap_session(original_session, true);
-		-- Inform xmppstream of the new session (passed to its callbacks)
-		original_session.stream:set_session(original_session);
-		-- Similar for connlisteners
-		c2s_sessions[session.conn] = original_session;
-
-		original_session.send(st.stanza("resumed", { xmlns = xmlns_sm,
-			h = string.format("%d", original_session.handled_stanza_count), previd = id }));
-
-		-- Fake an <a> with the h of the <resume/> from the client
-		original_session:dispatch_stanza(st.stanza("a", { xmlns = xmlns_sm,
-			h = stanza.attr.h }));
-
-		-- Ok, we need to re-send any stanzas that the client didn't see
-		-- ...they are what is now left in the outgoing stanza queue
-		-- We have to use the send of "session" because we don't want to add our resent stanzas
-		-- to the outgoing queue again
-		local queue = original_session.outgoing_stanza_queue;
-		session.log("debug", "resending all unacked stanzas that are still queued after resume, #queue = %d", #queue);
-		for i=1,#queue do
-			session.send(queue[i]);
-		end
-		session.log("debug", "all stanzas resent, now disabling send() in this migrated session, #queue = %d", #queue);
-		function session.send(stanza)
-			migrated_session_log("error", "Tried to send stanza on old session migrated by smacks resume (maybe there is a bug?): %s", tostring(stanza));
-			return false;
-		end
-		module:fire_event("smacks-hibernation-end", {origin = session, resumed = original_session, queue = queue});
-		request_ack_if_needed(original_session, true, "handle_resume", nil);
-	else
-		module:log("warn", "Client %s@%s[%s] tried to resume stream for %s@%s[%s]",
-			session.username or "?", session.host or "?", session.type,
-			original_session.username or "?", original_session.host or "?", original_session.type);
-		session.send(st.stanza("failed", { xmlns = xmlns_sm })
-			:tag("not-authorized", { xmlns = xmlns_errors }));
-	end
-	return true;
-end
-module:hook_stanza(xmlns_sm2, "resume", function (session, stanza) return handle_resume(session, stanza, xmlns_sm2); end);
-module:hook_stanza(xmlns_sm3, "resume", function (session, stanza) return handle_resume(session, stanza, xmlns_sm3); end);
-
-module:hook("csi-client-active", function (event)
-	if event.origin.smacks then
-		request_ack_if_needed(event.origin, true, "csi-active", nil);
-	end
-end);
-
-module:hook("csi-flushing", function(event)
-	local session = event.session;
-	if session.smacks then
-		if not session.awaiting_ack and not session.hibernating and not session.destroyed then
-			session.log("debug", "Sending <r> (csi-flushing)");
-			session.awaiting_ack = true; -- The send() call may invoke this event again, so set this first
-			(session.sends2s or session.send)(st.stanza("r", { xmlns = session.smacks }))
-		end
-	end
-end);
-
-local function handle_read_timeout(event)
-	local session = event.session;
-	if session.smacks then
-		if session.awaiting_ack then
-			if session.awaiting_ack_timer then
-				session.awaiting_ack_timer:stop();
-			end
-			if session.delayed_ack_timer then
-				session.delayed_ack_timer:stop();
-				session.delayed_ack_timer = nil;
-			end
-			return false; -- Kick the session
-		end
-		session.log("debug", "Sending <r> (read timeout)");
-		(session.sends2s or session.send)(st.stanza("r", { xmlns = session.smacks }));
-		session.awaiting_ack = true;
-		if not session.delayed_ack_timer then
-			session.delayed_ack_timer = stoppable_timer(delayed_ack_timeout, function()
-				delayed_ack_function(session, nil);
-			end);
-		end
-		return true;
-	end
-end
-
-module:hook("s2s-read-timeout", handle_read_timeout);
-module:hook("c2s-read-timeout", handle_read_timeout);