DNSBL server module

diff --git a/server_modules/dnsbl.js b/server_modules/dnsbl.js
new file mode 100644 (file)
index 0000000..984c0b4
--- /dev/null
+++ b/server_modules/dnsbl.js
@@ -0,0 +1,62 @@
+/**
+ * DNS Blacklist support
+ *
+ * Check the client against a blacklist before connection to an IRC server
+ */
+
+var dns = require('dns'),
+    kiwiModules = require('../server/modules');
+
+
+// The available DNS zones to check against
+var bl_zones = {
+    dronebl: '.dnsbl.dronebl.org'
+};
+
+// The DNS zone we should use
+var current_bl = 'dronebl';
+
+
+var module = new kiwiModules.Module('DNSBL');
+
+module.on('irc connecting', function (event, event_data) {
+    event.wait = true;
+
+    var client_addr = event_data.connection.state.client.websocket.handshake.real_address;
+
+    isBlacklisted(client_addr, function(is_blocked) {
+        if (is_blocked) {
+            var err = new Error('DNSBL blocked');
+            err.code = 'Blacklisted';
+
+            event_data.connection.emit('error', err);
+            event.preventDefault();
+            event.callback();
+
+        } else {
+            event.callback();
+        }
+    });
+});
+
+
+
+// The actual checking against the DNS blacklist
+function isBlacklisted(ip, callback) {
+    var host_lookup = reverseIp(ip) + bl_zones[current_bl];
+
+    dns.resolve4(host_lookup, function(err, domain) {
+        if (err) {
+            // Not blacklisted
+            callback(false);
+        } else {
+            // It is blacklisted
+            callback(true);
+        }
+    });
+}
+
+
+function reverseIp(ip) {
+    return ip.split('.').reverse().join('.');
+}
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