local jid = require "util.jid"; local st = require "util.stanza"; local new_throttle = require "util.throttle".create; local t_insert, t_concat = table.insert, table.concat; local xmlns_muc = "http://jabber.org/protocol/muc"; local period = math.max(module:get_option_number("muc_event_rate", 0.5), 0); local burst = math.max(module:get_option_number("muc_burst_factor", 6), 1); local max_nick_length = module:get_option_number("muc_max_nick_length", 23); -- Default chosen through scientific methods local dropped_count = 0; local dropped_jids; local function log_dropped() module:log("warn", "Dropped %d stanzas from %d JIDs: %s", dropped_count, #dropped_jids, t_concat(dropped_jids, ", ")); dropped_count = 0; dropped_jids = nil; end local function handle_stanza(event) local origin, stanza = event.origin, event.stanza; if stanza.name == "presence" and stanza.attr.type == "unavailable" then -- Don't limit room leaving return; end local dest_room, dest_host, dest_nick = jid.split(stanza.attr.to); local room = hosts[module.host].modules.muc.rooms[dest_room.."@"..dest_host]; if not room then return; end local from_jid = stanza.attr.from; local occupant = room._occupants[room._jid_nick[from_jid]]; if occupant and occupant.affiliation then module:log("debug", "Skipping stanza from affiliated user..."); return; elseif max_nick_length and stanza.name == "presence" and not room._occupants[stanza.attr.to] and #dest_nick > max_nick_length then module:log("debug", "Forbidding long (%d bytes) nick in %s", #dest_nick, dest_room) origin.send(st.error_reply(stanza, "modify", "policy-violation", "Your nick name is too long, please use a shorter one") :up():tag("x", { xmlns = xmlns_muc })); return true; end local throttle = room.throttle; if not room.throttle then throttle = new_throttle(period*burst, burst); room.throttle = throttle; end if not throttle:poll(1) then module:log("debug", "Dropping stanza for %s@%s from %s, over rate limit", dest_room, dest_host, from_jid); if not dropped_jids then dropped_jids = { [from_jid] = true, from_jid }; module:add_timer(5, log_dropped); elseif not dropped_jids[from_jid] then dropped_jids[from_jid] = true; t_insert(dropped_jids, from_jid); end dropped_count = dropped_count + 1; local reply = st.error_reply(stanza, "wait", "policy-violation", "The room is currently overactive, please try again later"); local body = stanza:get_child_text("body"); if body then reply:up():tag("body"):text(body):up(); end local x = stanza:get_child("x", xmlns_muc); if x then reply:add_child(st.clone(x)); end origin.send(reply); return true; end end function module.unload() for room_jid, room in pairs(hosts[module.host].modules.muc.rooms) do room.throttle = nil; end end module:hook("message/bare", handle_stanza, 501); module:hook("message/full", handle_stanza, 501); module:hook("presence/bare", handle_stanza, 501); module:hook("presence/full", handle_stanza, 501);