3 files changed, 127 insertions, 0 deletions
diff --git a/cli/dts/lib.deno.unstable.d.ts b/cli/dts/lib.deno.unstable.d.ts
index cde76d4d8..2bcba88da 100644
--- a/cli/dts/lib.deno.unstable.d.ts
+++ b/cli/dts/lib.deno.unstable.d.ts
@@ -1158,6 +1158,22 @@ declare namespace Deno {
     [Symbol.asyncIterator](): AsyncIterableIterator<[Uint8Array, Addr]>;
   }
 
+  /**
+   * @category Network
+   */
+  export interface TcpListenOptions extends ListenOptions {
+    /** When `true` the SO_REUSEPORT flag will be set on the listener. This
+     * allows multiple processes to listen on the same address and port.
+     *
+     * On Linux this will cause the kernel to distribute incoming connections
+     * across the different processes that are listening on the same address and
+     * port.
+     *
+     * This flag is only supported on Linux. It is silently ignored on other
+     * platforms. Defaults to `false`. */
+    reusePort?: boolean;
+  }
+
   /** **UNSTABLE**: New API, yet to be vetted.
    *
    * Unstable options which can be set when opening a Unix listener via
diff --git a/cli/tests/unit/net_test.ts b/cli/tests/unit/net_test.ts
index d2beb5566..8d004f424 100644
--- a/cli/tests/unit/net_test.ts
+++ b/cli/tests/unit/net_test.ts
@@ -1005,3 +1005,48 @@ Deno.test(
     }
   },
 );
+
+Deno.test({
+  ignore: Deno.build.os !== "linux",
+  permissions: { net: true },
+}, async function netTcpListenReusePort() {
+  const port = 4003;
+  const listener1 = Deno.listen({ port, reusePort: true });
+  const listener2 = Deno.listen({ port, reusePort: true });
+  let p1;
+  let p2;
+  let listener1Recv = false;
+  let listener2Recv = false;
+  while (!listener1Recv || !listener2Recv) {
+    if (!p1) {
+      p1 = listener1.accept().then((conn) => {
+        conn.close();
+        listener1Recv = true;
+        p1 = undefined;
+      }).catch(() => {});
+    }
+    if (!p2) {
+      p2 = listener2.accept().then((conn) => {
+        conn.close();
+        listener2Recv = true;
+        p2 = undefined;
+      }).catch(() => {});
+    }
+    const conn = await Deno.connect({ port });
+    conn.close();
+    await Promise.race([p1, p2]);
+  }
+  listener1.close();
+  listener2.close();
+});
+
+Deno.test({
+  ignore: Deno.build.os === "linux",
+  permissions: { net: true },
+}, function netTcpListenReusePortDoesNothing() {
+  const listener1 = Deno.listen({ port: 4003, reusePort: true });
+  assertThrows(() => {
+    Deno.listen({ port: 4003, reusePort: true });
+  }, Deno.errors.AddrInUse);
+  listener1.close();
+});
diff --git a/cli/tests/unit/tls_test.ts b/cli/tests/unit/tls_test.ts
index ee7636954..d3ef4d0bf 100644
--- a/cli/tests/unit/tls_test.ts
+++ b/cli/tests/unit/tls_test.ts
@@ -1410,3 +1410,69 @@ Deno.test(
     listener2.close();
   },
 );
+
+Deno.test({
+  ignore: Deno.build.os !== "linux",
+  permissions: { net: true },
+}, async function listenTlsReusePort() {
+  const hostname = "localhost";
+  const port = 4003;
+  const listener1 = Deno.listenTls({
+    hostname,
+    port,
+    cert,
+    key,
+    reusePort: true,
+  });
+  const listener2 = Deno.listenTls({
+    hostname,
+    port,
+    cert,
+    key,
+    reusePort: true,
+  });
+  let p1;
+  let p2;
+  let listener1Recv = false;
+  let listener2Recv = false;
+  while (!listener1Recv || !listener2Recv) {
+    if (!p1) {
+      p1 = listener1.accept().then((conn) => {
+        conn.close();
+        listener1Recv = true;
+        p1 = undefined;
+      }).catch(() => {});
+    }
+    if (!p2) {
+      p2 = listener2.accept().then((conn) => {
+        conn.close();
+        listener2Recv = true;
+        p2 = undefined;
+      }).catch(() => {});
+    }
+    const conn = await Deno.connectTls({ hostname, port, caCerts });
+    conn.close();
+    await Promise.race([p1, p2]);
+  }
+  listener1.close();
+  listener2.close();
+});
+
+Deno.test({
+  ignore: Deno.build.os === "linux",
+  permissions: { net: true },
+}, function listenTlsReusePortDoesNothing() {
+  const hostname = "localhost";
+  const port = 4003;
+  const listener1 = Deno.listenTls({
+    hostname,
+    port,
+    cert,
+    key,
+    reusePort: true,
+  });
+  assertThrows(() => {
+    Deno.listenTls({ hostname, port, cert, key, reusePort: true });
+  }, Deno.errors.AddrInUse);
+  listener1.close();
+});