dgram: add source-specific multicast support

doc/api/dgram.md

@@ -123,6 +123,21 @@ if (cluster.isMaster) {
 }
 ```
 
+### socket.addSourceSpecificMembership(sourceAddress, groupAddress\[, multicastInterface\])
+<!-- YAML
+added: REPLACEME
+-->
+* `sourceAddress` {string}
+* `groupAddress` {string}
+* `multicastInterface` {string}
+
+Tells the kernel to join a source-specific multicast channel at the given
+`sourceAddress` and `groupAddress`, using the `multicastInterface` with the
+`IP_ADD_SOURCE_MEMBERSHIP` socket option. If the `multicastInterface` argument
+is not specified, the operating system will choose one interface and will add
+membership to it. To add membership to every available interface, call
+`socket.addSourceSpecificMembership()` multiple times, once per interface.
+
 ### socket.address()
 <!-- YAML
 added: v0.1.99
@@ -297,6 +312,24 @@ never have reason to call this.
 If `multicastInterface` is not specified, the operating system will attempt to
 drop membership on all valid interfaces.
 
+### socket.dropSourceSpecificMembership(sourceAddress, groupAddress\[, multicastInterface\])
+<!-- YAML
+added: REPLACEME
+-->
+
+* `sourceAddress` {string}
+* `groupAddress` {string}
+* `multicastInterface` {string}
+
+Instructs the kernel to leave a source-specific multicast channel at the given
+`sourceAddress` and `groupAddress` using the `IP_DROP_SOURCE_MEMBERSHIP`
+socket option. This method is automatically called by the kernel when the
+socket is closed or the process terminates, so most apps will never have
+reason to call this.
+
+If `multicastInterface` is not specified, the operating system will attempt to
+drop membership on all valid interfaces.
+
 ### socket.getRecvBufferSize()
 <!-- YAML
 added: v8.7.0

lib/dgram.js

@@ -832,6 +832,55 @@ Socket.prototype.dropMembership = function(multicastAddress,
   }
 };
 
+Socket.prototype.addSourceSpecificMembership = function(sourceAddress,
+                                                        groupAddress,
+                                                        interfaceAddress) {
+  healthCheck(this);
+
+  if (typeof sourceAddress !== 'string') {
+    throw new errors.TypeError('ERR_INVALID_ARG_TYPE', 'sourceAddress',
+                               'string');
+  }
+
+  if (typeof groupAddress !== 'string') {
+    throw new errors.TypeError('ERR_INVALID_ARG_TYPE', 'groupAddress',
+                               'string');
+  }
+
+  const err =
+    this[kStateSymbol].handle.addSourceSpecificMembership(sourceAddress,
+                                                          groupAddress,
+                                                          interfaceAddress);
+  if (err) {
+    throw errnoException(err, 'addSourceSpecificMembership');
+  }
+};
+
+
+Socket.prototype.dropSourceSpecificMembership = function(sourceAddress,
+                                                         groupAddress,
+                                                         interfaceAddress) {
+  healthCheck(this);
+
+  if (typeof sourceAddress !== 'string') {
+    throw new errors.TypeError('ERR_INVALID_ARG_TYPE', 'sourceAddress',
+                               'string');
+  }
+
+  if (typeof groupAddress !== 'string') {
+    throw new errors.TypeError('ERR_INVALID_ARG_TYPE', 'groupAddress',
+                               'string');
+  }
+
+  const err =
+    this[kStateSymbol].handle.dropSourceSpecificMembership(sourceAddress,
+                                                           groupAddress,
+                                                           interfaceAddress);
+  if (err) {
+    throw errnoException(err, 'dropSourceSpecificMembership');
+  }
+};
+
 
 function healthCheck(socket) {
   if (!socket[kStateSymbol].handle) {

src/udp_wrap.cc

@@ -128,6 +128,10 @@ void UDPWrap::Initialize(Local<Object> target,
                       GetSockOrPeerName<UDPWrap, uv_udp_getsockname>);
   env->SetProtoMethod(t, "addMembership", AddMembership);
   env->SetProtoMethod(t, "dropMembership", DropMembership);
+  env->SetProtoMethod(t, "addSourceSpecificMembership",
+                      AddSourceSpecificMembership);
+  env->SetProtoMethod(t, "dropSourceSpecificMembership",
+                      DropSourceSpecificMembership);
   env->SetProtoMethod(t, "setMulticastInterface", SetMulticastInterface);
   env->SetProtoMethod(t, "setMulticastTTL", SetMulticastTTL);
   env->SetProtoMethod(t, "setMulticastLoopback", SetMulticastLoopback);
@@ -397,6 +401,44 @@ void UDPWrap::DropMembership(const FunctionCallbackInfo<Value>& args) {
   SetMembership(args, UV_LEAVE_GROUP);
 }
 
+void UDPWrap::SetSourceMembership(const FunctionCallbackInfo<Value>& args,
+                                  uv_membership membership) {
+  UDPWrap* wrap;
+  ASSIGN_OR_RETURN_UNWRAP(&wrap,
+                          args.Holder(),
+                          args.GetReturnValue().Set(UV_EBADF));
+
+  CHECK_EQ(args.Length(), 3);
+
+  node::Utf8Value source_address(args.GetIsolate(), args[0]);
+  node::Utf8Value group_address(args.GetIsolate(), args[1]);
+  node::Utf8Value iface(args.GetIsolate(), args[2]);
+
+  if (*iface == nullptr) return;
+  const char* iface_cstr = *iface;
+  if (args[2]->IsUndefined() || args[2]->IsNull()) {
+    iface_cstr = nullptr;
+  }
+
+  int err = uv_udp_set_source_membership(&wrap->handle_,
+                                         *group_address,
+                                         iface_cstr,
+                                         *source_address,
+                                         membership);
+  args.GetReturnValue().Set(err);
+}
+
+void UDPWrap::AddSourceSpecificMembership(
+  const FunctionCallbackInfo<Value>& args) {
+  SetSourceMembership(args, UV_JOIN_GROUP);
+}
+
+
+void UDPWrap::DropSourceSpecificMembership(
+  const FunctionCallbackInfo<Value>& args) {
+  SetSourceMembership(args, UV_LEAVE_GROUP);
+}
+
 
 void UDPWrap::DoSend(const FunctionCallbackInfo<Value>& args, int family) {
   Environment* env = Environment::GetCurrent(args);

src/udp_wrap.h

@@ -55,6 +55,10 @@ class UDPWrap: public HandleWrap {
   static void RecvStop(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void AddMembership(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void DropMembership(const v8::FunctionCallbackInfo<v8::Value>& args);
+  static void AddSourceSpecificMembership(
+      const v8::FunctionCallbackInfo<v8::Value>& args);
+  static void DropSourceSpecificMembership(
+      const v8::FunctionCallbackInfo<v8::Value>& args);
   static void SetMulticastInterface(
       const v8::FunctionCallbackInfo<v8::Value>& args);
   static void SetMulticastTTL(const v8::FunctionCallbackInfo<v8::Value>& args);
@@ -88,6 +92,9 @@ class UDPWrap: public HandleWrap {
                      int family);
   static void SetMembership(const v8::FunctionCallbackInfo<v8::Value>& args,
                             uv_membership membership);
+  static void SetSourceMembership(
+      const v8::FunctionCallbackInfo<v8::Value>& args,
+      uv_membership membership);
 
   static void OnAlloc(uv_handle_t* handle,
                       size_t suggested_size,