diff --git a/plugins/mod_smacks.lua b/plugins/mod_smacks.lua
new file mode 100644
index 0000000..18e2ded
--- /dev/null
+++ b/plugins/mod_smacks.lua
@@ -0,0 +1,353 @@
+local st = require "util.stanza";
+local uuid_generate = require "util.uuid".generate;
+
+local t_insert, t_remove = table.insert, table.remove;
+local math_min = math.min;
+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_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", 300);
+local s2s_smacks = module:get_option_boolean("smacks_enabled_s2s", false);
+local max_unacked_stanzas = module:get_option_number("smacks_max_unacked_stanzas", 0);
+local core_process_stanza = prosody.core_process_stanza;
+local sessionmanager = require"core.sessionmanager";
+
+local c2s_sessions = module:shared("/*/c2s/sessions");
+local session_registry = {};
+
+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_type == "c2s" 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 outgoing_stanza_filter(stanza, session)
+ local is_stanza = stanza.attr and not stanza.attr.xmlns;
+ if is_stanza and not stanza._cached then -- Stanza in default stream namespace
+ local queue = session.outgoing_stanza_queue;
+ local cached_stanza = st.clone(stanza);
+ cached_stanza._cached = true;
+
+ if cached_stanza and cached_stanza:get_child("delay", xmlns_delay) == nil then
+ cached_stanza = cached_stanza:tag("delay", { xmlns = xmlns_delay, from = session.host, stamp = datetime.datetime()});
+ end
+
+ queue[#queue+1] = cached_stanza;
+ session.log("debug", "#queue = %d", #queue);
+ if session.hibernating then
+ session.log("debug", "hibernating, stanza queued");
+ return ""; -- Hack to make session.send() not return nil
+ end
+ if #queue > max_unacked_stanzas and not session.awaiting_ack then
+ session.awaiting_ack = true;
+ return tostring(stanza)..tostring(st.stanza("r", { xmlns = session.smacks }));
+ end
+ 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, -1000);
+
+ local session_close = session.close;
+ function session.close(...)
+ if session.resumption_token then
+ session_registry[session.resumption_token] = nil;
+ session.resumption_token = nil;
+ end
+ return session_close(...);
+ end
+ return session;
+end
+
+local function wrap_session_in(session, resume)
+ if not resume then
+ session.handled_stanza_count = 0;
+ add_filter(session, "stanzas/in", count_incoming_stanzas, 1000);
+ end
+
+ 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[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 }));
+ 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)
+ module:add_timer(0, 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
+ (origin.sends2s or origin.send)(st.stanza("a", { xmlns = xmlns_sm, h = tostring(origin.handled_stanza_count) }));
+ 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;
+ -- Remove handled stanzas from outgoing_stanza_queue
+ --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"; };
+ 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
+ end
+ for i=1,math_min(handled_stanza_count,#queue) do
+ t_remove(origin.outgoing_stanza_queue, 1);
+ end
+ origin.log("debug", "#queue = %d", #queue);
+ origin.last_acknowledged_stanza = origin.last_acknowledged_stanza + handled_stanza_count;
+ 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
+
+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
+
+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("warn", "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;
+ 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 false and 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
+ session.log("debug", "Destroying session for hibernating too long");
+ session_registry[session.resumption_token] = nil;
+ 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);
+
+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[id];
+ if not original_session then
+ session.log("debug", "Tried to resume non-existent session with id %s", id);
+ session.send(st.stanza("failed", { xmlns = xmlns_sm })
+ :tag("item-not-found", { xmlns = xmlns_errors })
+ );
+ elseif session.username == original_session.username
+ and session.host == original_session.host then
+ session.log("debug", "mod_smacks resuming existing session...");
+ -- TODO: All this should move to sessionmanager (e.g. session:replace(new_session))
+ if original_session.conn then
+ session.log("debug", "mod_smacks closing an old connection for this session");
+ local conn = original_session.conn;
+ c2s_sessions[conn] = nil;
+ conn:close();
+ end
+ original_session.ip = session.ip;
+ original_session.conn = session.conn;
+ original_session.send = session.send;
+ original_session.send.filter = original_session.filter;
+ original_session.stream = session.stream;
+ original_session.secure = session.secure;
+ original_session.hibernating = nil;
+ 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;
+
+ session.send(st.stanza("resumed", { xmlns = xmlns_sm,
+ h = original_session.handled_stanza_count, previd = id }));
+
+ -- Fake an with the h of the 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
+ local queue = original_session.outgoing_stanza_queue;
+ session.log("debug", "#queue = %d", #queue);
+ for i=1,#queue do
+ session.send(queue[i]);
+ end
+ session.log("debug", "#queue = %d -- after send", #queue);
+ 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);