From 1305d223fafc79be7fad07aee1f4348b2eaeaae5 Mon Sep 17 00:00:00 2001
From: Sam Anthony <sam@samanthony.xyz>
Date: Sat, 23 Nov 2024 13:12:29 -0500
Subject: rmulticast: use DatagramChannel

---
 src/main/java/derms/net/Net.java | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 src/main/java/derms/net/Net.java

(limited to 'src/main/java/derms/net/Net.java')

diff --git a/src/main/java/derms/net/Net.java b/src/main/java/derms/net/Net.java
new file mode 100644
index 0000000..f2eb1fd
--- /dev/null
+++ b/src/main/java/derms/net/Net.java
@@ -0,0 +1,19 @@
+package derms.net;
+
+import java.net.NetworkInterface;
+import java.net.SocketException;
+import java.util.Enumeration;
+import java.util.NoSuchElementException;
+
+public class Net {
+    /** Return the first non-loopback multicast interface in the system, or throw exception if no such interface exists. */
+    public static NetworkInterface getMulticastInterface() throws SocketException, NoSuchElementException {
+        Enumeration<NetworkInterface> ifss =  NetworkInterface.getNetworkInterfaces();
+        while (ifss.hasMoreElements()) {
+            NetworkInterface ifs = ifss.nextElement();
+            if (ifs.supportsMulticast() && !ifs.isLoopback() && ifs.isUp())
+                return ifs;
+        }
+        throw new NoSuchElementException("no multicast interface available");
+    }
+}
-- 
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