feat: Module to restrict muc access.

resources/prosody-plugins/mod_muc_filter_access.lua

+-- Restricts access to a muc component to certain domains
+-- Copyright (C) 2023-present 8x8, Inc.
+
+-- a list of (authenticated)domains that can access rooms(send presence)
+local whitelist = module:get_option_set("muc_filter_whitelist");
+
+if not whitelist then
+    module:log("warn", "No 'muc_filter_whitelist' option set, disabling muc_filter_access, plugin inactive");
+    return
+end
+
+local jid_split = require "util.jid".split;
+
+local function incoming_presence_filter(event)
+    local stanza = event.stanza;
+    local _, domain, _ = jid_split(stanza.attr.from);
+
+    if not stanza.attr.from or not whitelist:contains(domain) then
+        -- Filter presence
+        module:log("error", "Filtering unauthorized presence: %s", stanza:top_tag());
+        return true;
+    end
+end
+
+for _, jid_type in ipairs({ "host", "bare", "full" }) do
+    module:hook("presence/"..jid_type, incoming_presence_filter, 2000);
+end