mod_smacks: Fixes for monkey-patched sessionmanager.destroy to handle stream resumption, and to fall back to stock destroy() if the session is not smacks-enabled.
local st = require "util.stanza";
local t_insert, t_remove = table.insert, table.remove;
local math_min = math.min;
local tonumber, tostring = tonumber, tostring;
local add_filter = require "util.filters".add_filter;
local timer = require "util.timer";
local xmlns_sm = "urn:xmpp:sm:2";
local sm_attr = { xmlns = xmlns_sm };
local resume_timeout = 300;
local max_unacked_stanzas = 0;
module:add_event_hook("stream-features",
function (session, features)
features:tag("sm", sm_attr):tag("optional"):up():up();
end);
module:hook("s2s-stream-features",
function (data)
data.features:tag("sm", sm_attr):tag("optional"):up():up();
end);
module:hook_stanza(xmlns_sm, "enable",
function (session, stanza)
module:log("debug", "Enabling stream management");
session.smacks = true;
-- Overwrite process_stanza() and send()
local queue = {};
session.outgoing_stanza_queue = queue;
session.last_acknowledged_stanza = 0;
local _send = session.sends2s or session.send;
local function new_send(stanza)
local attr = stanza.attr;
if attr and not attr.xmlns then -- Stanza in default stream namespace
queue[#queue+1] = st.clone(stanza);
end
local ok, err = _send(stanza);
if ok and #queue > max_unacked_stanzas and not session.awaiting_ack then
session.awaiting_ack = true;
return _send(st.stanza("r", { xmlns = xmlns_sm }));
end
return ok, err;
end
if session.sends2s then
session.sends2s = new_send;
else
session.send = new_send;
end
session.handled_stanza_count = 0;
add_filter(session, "stanzas/in", function (stanza)
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);
if not stanza.attr.resume then -- FIXME: Resumption should be a different spec :/
_send(st.stanza("enabled", sm_attr));
return true;
end
end, 100);
module:hook_stanza(xmlns_sm, "r", function (origin, stanza)
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 = tostring(origin.handled_stanza_count) }));
return true;
end);
module:hook_stanza(xmlns_sm, "a", function (origin, stanza)
if not origin.smacks then return; end
origin.awaiting_ack = nil;
-- Remove handled stanzas from outgoing_stanza_queue
local handled_stanza_count = tonumber(stanza.attr.h)-origin.last_acknowledged_stanza;
local queue = origin.outgoing_stanza_queue;
if handled_stanza_count > #queue then
module:log("warn", "The client says it handled %d new stanzas, but we only sent %d :)",
handled_stanza_count, #queue);
for i=1,#queue do
module:log("debug", "Q item %d: %s", i, tostring(queue[i]));
end
end
for i=1,math_min(handled_stanza_count,#queue) do
t_remove(origin.outgoing_stanza_queue, 1);
end
origin.last_acknowledged_stanza = origin.last_acknowledged_stanza + handled_stanza_count;
return true;
end);
--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
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
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
local _destroy_session = sessionmanager.destroy_session;
function sessionmanager.destroy_session(session, err)
if session.smacks then
if not session.resumption_token then
local queue = session.outgoing_stanza_queue;
if #queue > 0 then
module:log("warn", "Destroying session with %d unacked stanzas:", #queue);
for i=1,#queue do
module:log("warn", "::%s", tostring(queue[i]));
end
handle_unacked_stanzas(session);
end
else
session.hibernating = true;
timer.add_task(resume_timeout, function ()
if session.hibernating then
session.resumption_token = nil;
sessionmanager.destroy_session(session); -- Re-destroy
end
end);
return; -- Postpone destruction for now
end
end
return _destroy_session(session, err);
end