Fix EINVAL when setting IPv6 multicast membership (#17478)

test/js/node/dgram/node-dgram.test.js

@@ -0,0 +1,53 @@
+import { describe, expect, it } from "bun:test";
+import * as dgram from "node:dgram";
+import { isWindows, isMacOS, isIPv6 } from "harness";
+
+describe.skipIf(!isIPv6())("node:dgram", () => {
+  it("adds membership successfully (IPv6)", () => {
+    const socket = makeSocket6();
+    socket.bind(0, () => {
+      socket.addMembership("ff01::1", getInterface());
+      if (!isMacOS) {
+        // macOS seems to be iffy with automatically choosing an interface.
+        socket.addMembership("ff02::1");
+      }
+    });
+  });
+
+  it("doesn't add membership given invalid inputs (IPv6)", () => {
+    const { promise, resolve, reject } = Promise.withResolvers();
+    const socket = makeSocket6();
+    socket.bind(0, () => {
+      expect(() => {
+        // fe00:: is not a valid multicast address
+        socket.addMembership("fe00::", getInterface());
+        reject();
+      }).toThrow();
+      expect(() => {
+        socket.addMembership("fe00::");
+        reject();
+      }).toThrow();
+      resolve();
+    });
+    return promise;
+  });
+});
+
+function makeSocket6() {
+  return dgram.createSocket({
+    type: "udp6",
+    ipv6Only: true,
+  });
+}
+
+function getInterface() {
+  if (isWindows) {
+    return "::%1";
+  }
+
+  if (isMacOS) {
+    return "::%lo0";
+  }
+
+  return "::%lo";
+}