unix, win: add uv_udp_set_multicast_interface()

include/uv.h

@@ -978,6 +978,20 @@ UV_EXTERN int uv_udp_set_multicast_loop(uv_udp_t* handle, int on);
  */
 UV_EXTERN int uv_udp_set_multicast_ttl(uv_udp_t* handle, int ttl);
 
+
+/*
+ * Set the multicast interface to send on
+ *
+ * Arguments:
+ *  handle              UDP handle. Should have been initialized with
+ *                      `uv_udp_init`.
+ *  interface_addr      interface address
+ *
+ * Returns:
+ *  0 on success, or an error code < 0 on failure.
+ */
+UV_EXTERN int uv_udp_set_multicast_interface(uv_udp_t* handle, const char* interface_addr);
+
 /*
  * Set broadcast on or off
  *

src/unix/udp.c

@@ -539,6 +539,31 @@ int uv_udp_set_multicast_loop(uv_udp_t* handle, int on) {
   return uv__setsockopt_maybe_char(handle, IP_MULTICAST_LOOP, on);
 }
 
+int uv_udp_set_multicast_interface(uv_udp_t* handle, const char* interface_addr) {
+  struct in_addr addr;
+  int err;
+
+  memset(&addr, 0, sizeof addr);
+
+  if (interface_addr) {
+    err = uv_inet_pton(AF_INET, interface_addr, &addr.s_addr);
+    if (err)
+      return err;
+  } else {
+    addr.s_addr = htonl(INADDR_ANY);
+  }
+
+  if (setsockopt(handle->io_watcher.fd,
+                 IPPROTO_IP,
+                 IP_MULTICAST_IF,
+                 (void*) &addr,
+                 sizeof addr) == -1) {
+    return -errno;
+  }
+
+  return 0;
+}
+
 
 int uv_udp_getsockname(uv_udp_t* handle, struct sockaddr* name, int* namelen) {
   socklen_t socklen;

src/win/udp.c

@@ -585,6 +585,46 @@ int uv_udp_set_membership(uv_udp_t* handle, const char* multicast_addr,
 }
 
 
+int uv_udp_set_multicast_interface(uv_udp_t* handle, const char* interface_addr) {
+  struct in_addr addr;
+  int err;
+
+  memset(&addr, 0, sizeof addr);
+
+  if (handle->flags & UV_HANDLE_IPV6) {
+    return UV_ENOSYS;
+  }
+
+  /* If the socket is unbound, bind to inaddr_any. */
+  if (!(handle->flags & UV_HANDLE_BOUND)) {
+    err = uv_udp_try_bind(handle,
+                          (const struct sockaddr*) &uv_addr_ip4_any_,
+                          sizeof(uv_addr_ip4_any_),
+                          0);
+    if (err)
+      return uv_translate_sys_error(err);
+  }
+
+  if (interface_addr) {
+    err = uv_inet_pton(AF_INET, interface_addr, &addr.s_addr);
+    if (err)
+      return err;
+  } else {
+    addr.s_addr = htonl(INADDR_ANY);
+  }
+
+  if (setsockopt(handle->socket,
+                 IPPROTO_IP,
+                 IP_MULTICAST_IF,
+                 (char*) &addr,
+                 sizeof addr) == SOCKET_ERROR) {
+    return uv_translate_sys_error(WSAGetLastError());
+  }
+
+  return 0;
+}
+
+
 int uv_udp_set_broadcast(uv_udp_t* handle, int value) {
   BOOL optval = (BOOL) value;
   int err;

test/test-list.h

@@ -81,6 +81,7 @@ TEST_DECLARE   (tcp_bind6_localhost_ok)
 TEST_DECLARE   (udp_send_and_recv)
 TEST_DECLARE   (udp_multicast_join)
 TEST_DECLARE   (udp_multicast_ttl)
+TEST_DECLARE   (udp_multicast_interface)
 TEST_DECLARE   (udp_dgram_too_big)
 TEST_DECLARE   (udp_dual_stack)
 TEST_DECLARE   (udp_ipv6_only)

test/test-udp-multicast-interface.c

@@ -0,0 +1,87 @@
+/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "uv.h"
+#include "task.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define CHECK_HANDLE(handle) \
+  ASSERT((uv_udp_t*)(handle) == &server || (uv_udp_t*)(handle) == &client)
+
+static uv_udp_t server;
+static uv_udp_t client;
+
+static int sv_send_cb_called;
+static int close_cb_called;
+
+
+static void close_cb(uv_handle_t* handle) {
+  CHECK_HANDLE(handle);
+  close_cb_called++;
+}
+
+
+static void sv_send_cb(uv_udp_send_t* req, int status) {
+  ASSERT(req != NULL);
+  ASSERT(status == 0);
+  CHECK_HANDLE(req->handle);
+
+  sv_send_cb_called++;
+
+  uv_close((uv_handle_t*) req->handle, close_cb);
+}
+
+
+TEST_IMPL(udp_multicast_interface) {
+  int r;
+  uv_udp_send_t req;
+  uv_buf_t buf;
+  struct sockaddr_in addr = uv_ip4_addr("239.255.0.1", TEST_PORT);
+
+  r = uv_udp_init(uv_default_loop(), &server);
+  ASSERT(r == 0);
+
+  r = uv_udp_bind(&server, uv_ip4_addr("0.0.0.0", 0), 0);
+  ASSERT(r == 0);
+
+  r = uv_udp_set_multicast_interface(&server, "0.0.0.0");
+  ASSERT(r == 0);
+
+  /* server sends "PING" */
+  buf = uv_buf_init("PING", 4);
+  r = uv_udp_send(&req, &server, &buf, 1, addr, sv_send_cb);
+  ASSERT(r == 0);
+
+  ASSERT(close_cb_called == 0);
+  ASSERT(sv_send_cb_called == 0);
+
+  /* run the loop till all events are processed */
+  uv_run(uv_default_loop(), UV_RUN_DEFAULT);
+
+  ASSERT(sv_send_cb_called == 1);
+  ASSERT(close_cb_called == 1);
+
+  MAKE_VALGRIND_HAPPY();
+  return 0;
+}

uv.gyp

@@ -387,6 +387,7 @@
         'test/test-udp-multicast-ttl.c',
         'test/test-ip4-addr.c',
         'test/test-ip6-addr.c',
+        'test/test-udp-multicast-interface.c',
       ],
       'conditions': [
         [ 'OS=="win"', {