add uv_udp_set_membership for unix multicast support

- test-udp-multicast-join tests that multicast packets can be received
- stub src/win/udp.c until support added

include/uv.h

@@ -239,6 +239,11 @@ typedef void (*uv_after_work_cb)(uv_work_t* req);
 typedef void (*uv_fs_event_cb)(uv_fs_event_t* handle, const char* filename,
     int events, int status);
 
+typedef enum {
+  UV_LEAVE_GROUP = 0,
+  UV_JOIN_GROUP
+} uv_membership;
+
 
 struct uv_err_s {
   /* read-only */
@@ -550,6 +555,21 @@ int uv_udp_bind(uv_udp_t* handle, struct sockaddr_in addr, unsigned flags);
 int uv_udp_bind6(uv_udp_t* handle, struct sockaddr_in6 addr, unsigned flags);
 int uv_udp_getsockname(uv_udp_t* handle, struct sockaddr* name, int* namelen);
 
+/*
+ * Set membership for a multicast address
+ *
+ * Arguments:
+ *  handle              UDP handle. Should have been initialized with `uv_udp_init`.
+ *  multicast_addr      multicast address to set membership for
+ *  interface_addr      interface address
+ *  membership          Should be UV_JOIN_GROUP or UV_LEAVE_GROUP
+ *
+ * Returns:
+ *  0 on success, -1 on error.
+ */
+int uv_udp_set_membership(uv_udp_t* handle, const char* multicast_addr,
+  const char* interface_addr, uv_membership membership);
+
 /*
  * Send data. If the socket has not previously been bound with `uv_udp_bind`
  * or `uv_udp_bind6`, it is bound to 0.0.0.0 (the "all interfaces" address)

src/unix/udp.c

@@ -459,6 +459,42 @@ int uv__udp_bind6(uv_udp_t* handle, struct sockaddr_in6 addr, unsigned flags) {
 }
 
 
+int uv_udp_set_membership(uv_udp_t* handle, const char* multicast_addr,
+  const char* interface_addr, uv_membership membership) {
+
+  int optname;
+  struct ip_mreq mreq;
+  memset(&mreq, 0, sizeof mreq);
+
+  if (interface_addr) {
+    mreq.imr_interface.s_addr = inet_addr(interface_addr);
+  } else {
+    mreq.imr_interface.s_addr = htonl(INADDR_ANY);
+  }
+
+  mreq.imr_multiaddr.s_addr = inet_addr(multicast_addr);
+
+  switch (membership) {
+  case UV_JOIN_GROUP:
+    optname = IP_ADD_MEMBERSHIP;
+    break;
+  case UV_LEAVE_GROUP:
+    optname = IP_DROP_MEMBERSHIP;
+    break;
+  default:
+    uv__set_sys_error(handle->loop, EFAULT);
+    return -1;
+  }
+
+  if (setsockopt(handle->fd, IPPROTO_IP, optname, (void*) &mreq, sizeof mreq) == -1) {
+    uv__set_sys_error(handle->loop, errno);
+    return -1;
+  }
+
+  return 0;
+}
+
+
 int uv_udp_getsockname(uv_udp_t* handle, struct sockaddr* name,
     int* namelen) {
   socklen_t socklen;

src/win/udp.c

@@ -223,6 +223,15 @@ int uv__udp_bind6(uv_udp_t* handle, struct sockaddr_in6 addr,
 }
 
 
+int uv_udp_set_membership(uv_udp_t* handle, const char* multicast_addr,
+  const char* interface_addr, uv_membership membership) {
+
+  /* not implemented yet */
+  uv__set_sys_error(handle->loop, ENOSYS);
+  return -1;
+}
+
+
 static void uv_udp_queue_recv(uv_loop_t* loop, uv_udp_t* handle) {
   uv_req_t* req;
   uv_buf_t buf;

test/test-list.h

@@ -43,6 +43,7 @@ TEST_DECLARE   (tcp_bind6_error_fault)
 TEST_DECLARE   (tcp_bind6_error_inval)
 TEST_DECLARE   (tcp_bind6_localhost_ok)
 TEST_DECLARE   (udp_send_and_recv)
+TEST_DECLARE   (udp_multicast_join)
 TEST_DECLARE   (udp_dgram_too_big)
 TEST_DECLARE   (udp_dual_stack)
 TEST_DECLARE   (udp_ipv6_only)
@@ -155,6 +156,7 @@ TASK_LIST_START
   TEST_ENTRY  (udp_dgram_too_big)
   TEST_ENTRY  (udp_dual_stack)
   TEST_ENTRY  (udp_ipv6_only)
+  TEST_ENTRY  (udp_multicast_join)
 
   TEST_ENTRY  (pipe_bind_error_addrinuse)
   TEST_ENTRY  (pipe_bind_error_addrnotavail)

test/test-udp-multicast-join.c

@@ -0,0 +1,139 @@
+/* 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 cl_recv_cb_called;
+
+static int sv_send_cb_called;
+
+static int close_cb_called;
+
+static uv_buf_t alloc_cb(uv_handle_t* handle, size_t suggested_size) {
+  static char slab[65536];
+
+  CHECK_HANDLE(handle);
+  ASSERT(suggested_size <= sizeof slab);
+
+  return uv_buf_init(slab, sizeof slab);
+}
+
+
+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);
+}
+
+
+static void cl_recv_cb(uv_udp_t* handle,
+                       ssize_t nread,
+                       uv_buf_t buf,
+                       struct sockaddr* addr,
+                       unsigned flags) {
+  CHECK_HANDLE(handle);
+  ASSERT(flags == 0);
+
+  cl_recv_cb_called++;
+
+  if (nread < 0) {
+    ASSERT(0 && "unexpected error");
+  }
+
+  if (nread == 0) {
+    /* Returning unused buffer */
+    /* Don't count towards cl_recv_cb_called */
+    ASSERT(addr == NULL);
+    return;
+  }
+
+  ASSERT(addr != NULL);
+  ASSERT(nread == 4);
+  ASSERT(!memcmp("PING", buf.base, nread));
+
+  /* we are done with the client handle, we can close it */
+  uv_close((uv_handle_t*) &client, close_cb);
+}
+
+
+TEST_IMPL(udp_multicast_join) {
+  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_init(uv_default_loop(), &client);
+  ASSERT(r == 0);
+
+  /* bind to the desired port */
+  r = uv_udp_bind(&client, addr, 0);
+  ASSERT(r == 0);
+
+  /* join the multicast channel */
+  r = uv_udp_set_membership(&client, "239.255.0.1", NULL, UV_JOIN_GROUP);
+  ASSERT(r == 0);
+
+  r = uv_udp_recv_start(&client, alloc_cb, cl_recv_cb);
+  ASSERT(r == 0);
+
+  buf = uv_buf_init("PING", 4);
+
+  /* server sends "PING" */
+  r = uv_udp_send(&req, &server, &buf, 1, addr, sv_send_cb);
+  ASSERT(r == 0);
+
+  ASSERT(close_cb_called == 0);
+  ASSERT(cl_recv_cb_called == 0);
+  ASSERT(sv_send_cb_called == 0);
+
+  /* run the loop till all events are processed */
+  uv_run(uv_default_loop());
+
+  ASSERT(cl_recv_cb_called == 1);
+  ASSERT(sv_send_cb_called == 1);
+  ASSERT(close_cb_called == 2);
+
+  return 0;
+}

uv.gyp

@@ -285,6 +285,7 @@
         'test/test-udp-dgram-too-big.c',
         'test/test-udp-ipv6.c',
         'test/test-udp-send-and-recv.c',
+        'test/test-udp-multicast-join.c',
       ],
       'conditions': [
         [ 'OS=="win"', {