dgram: add option or recvmmsg

Author: theanarkh

doc/api/dgram.md

@@ -968,6 +968,8 @@ changes:
     specified by the NAT.
   * `sendBlockList` {net.BlockList} `sendBlockList` can be used for disabling outbound
     access to specific IP addresses, IP ranges, or IP subnets.
+  * `msgCount` {integer} `msgCount` can be used to receive multiple messages at once via `recvmmsg`.
+    **Default:** `0`, disabled.
 * `callback` {Function} Attached as a listener for `'message'` events. Optional.
 * Returns: {dgram.Socket}
 

lib/dgram.js

@@ -112,7 +112,7 @@ function Socket(type, listener) {
   let sendBufferSize;
   let receiveBlockList;
   let sendBlockList;
-
+  let msgCount;
   let options;
   if (type !== null && typeof type === 'object') {
     options = type;
@@ -138,9 +138,13 @@ function Socket(type, listener) {
       }
       sendBlockList = options.sendBlockList;
     }
+    if (options.msgCount) {
+      validateUint32(options.msgCount, 'options.msgCount', true);
+      msgCount = options.msgCount;
+    }
   }
 
-  const handle = newHandle(type, lookup);
+  const handle = newHandle(type, lookup, msgCount);
   handle[owner_symbol] = this;
 
   this[async_id_symbol] = handle.getAsyncId();
@@ -162,6 +166,7 @@ function Socket(type, listener) {
     sendBufferSize,
     receiveBlockList,
     sendBlockList,
+    msgCount,
   };
 
   if (options?.signal !== undefined) {
@@ -380,6 +385,7 @@ Socket.prototype.bind = function(port_, address_ /* , callback */) {
     }
 
     if (cluster.isWorker && !exclusive) {
+      // TODO(theanarkh): support recvmmsg
       bindServerHandle(this, {
         address: ip,
         port: port,

lib/internal/dgram.js

@@ -28,7 +28,7 @@ function lookup6(lookup, address, callback) {
   return lookup(address || '::1', 6, callback);
 }
 
-function newHandle(type, lookup) {
+function newHandle(type, lookup, mmsgCount) {
   if (lookup === undefined) {
     if (dns === undefined) {
       dns = require('dns');
@@ -40,14 +40,14 @@ function newHandle(type, lookup) {
   }
 
   if (type === 'udp4') {
-    const handle = new UDP();
+    const handle = new UDP(mmsgCount);
 
     handle.lookup = FunctionPrototypeBind(lookup4, handle, lookup);
     return handle;
   }
 
   if (type === 'udp6') {
-    const handle = new UDP();
+    const handle = new UDP(mmsgCount);
 
     handle.lookup = FunctionPrototypeBind(lookup6, handle, lookup);
     handle.bind = handle.bind6;

src/udp_wrap.cc

@@ -142,20 +142,35 @@ void UDPWrapBase::RegisterExternalReferences(
   registry->Register(RecvStop);
 }
 
-UDPWrap::UDPWrap(Environment* env, Local<Object> object)
+UDPWrap::UDPWrap(Environment* env, Local<Object> object, uint32_t msg_count)
     : HandleWrap(env,
                  object,
                  reinterpret_cast<uv_handle_t*>(&handle_),
                  AsyncWrap::PROVIDER_UDPWRAP) {
   object->SetAlignedPointerInInternalField(
       UDPWrapBase::kUDPWrapBaseField, static_cast<UDPWrapBase*>(this));
-
-  int r = uv_udp_init(env->event_loop(), &handle_);
+  int r;
+  if (msg_count > 0) {
+    r = uv_udp_init_ex(env->event_loop(),
+                       &handle_,
+                       AF_UNSPEC | UV_UDP_RECVMMSG);
+  } else {
+    r = uv_udp_init(env->event_loop(), &handle_);
+  }
   CHECK_EQ(r, 0);  // can't fail anyway
-
+  msg_count_ = msg_count;
+  mmsg_buf_ = uv_buf_init(nullptr, 0);
   set_listener(this);
 }
 
+UDPWrap::~UDPWrap() {
+  // Libuv does not release the memory of memory which allocated
+  // by handle->alloc_cb when we call close in handle->read_cb,
+  // so we should release the memory here if necessary.
+  if (using_recvmmsg()) {
+    release_buf();
+  }
+}
 
 void UDPWrap::Initialize(Local<Object> target,
                          Local<Value> unused,
@@ -270,8 +285,12 @@ void UDPWrap::RegisterExternalReferences(ExternalReferenceRegistry* registry) {
 
 void UDPWrap::New(const FunctionCallbackInfo<Value>& args) {
   CHECK(args.IsConstructCall());
+  uint32_t msg_count = 0;
+  if (args[0]->IsUint32()) {
+    msg_count = args[0].As<Uint32>()->Value();
+  }
   Environment* env = Environment::GetCurrent(args);
-  new UDPWrap(env, args.This());
+  new UDPWrap(env, args.This(), msg_count);
 }
 
 
@@ -741,6 +760,12 @@ void UDPWrap::OnAlloc(uv_handle_t* handle,
 }
 
 uv_buf_t UDPWrap::OnAlloc(size_t suggested_size) {
+  if (using_recvmmsg()) {
+    suggested_size *= msg_count_;
+    mmsg_buf_ = uv_buf_init(reinterpret_cast<char*>(malloc(suggested_size)),
+                            suggested_size);
+    return mmsg_buf_;
+  }
   return env()->allocate_managed_buffer(suggested_size);
 }
 
@@ -759,7 +784,17 @@ void UDPWrap::OnRecv(ssize_t nread,
                      unsigned int flags) {
   Environment* env = this->env();
   Isolate* isolate = env->isolate();
-  std::unique_ptr<BackingStore> bs = env->release_managed_buffer(buf_);
+  std::unique_ptr<BackingStore> bs;
+
+  auto cleanup = OnScopeLeave([&]() {
+    if (using_recvmmsg() && (nread <= 0 || (flags & UV_UDP_MMSG_FREE))) {
+      release_buf();
+    }
+  });
+
+  if (!using_recvmmsg()) {
+    bs = env->release_managed_buffer(buf_);
+  }
   if (nread == 0 && addr == nullptr) {
     return;
   }
@@ -778,6 +813,10 @@ void UDPWrap::OnRecv(ssize_t nread,
     return;
   } else if (nread == 0) {
     bs = ArrayBuffer::NewBackingStore(isolate, 0);
+  } else if (using_recvmmsg()) {
+    bs = ArrayBuffer::NewBackingStore(
+      isolate, nread, BackingStoreInitializationMode::kUninitialized);
+    memcpy(bs->Data(), buf_.base, nread);
   } else if (static_cast<size_t>(nread) != bs->ByteLength()) {
     CHECK_LE(static_cast<size_t>(nread), bs->ByteLength());
     std::unique_ptr<BackingStore> old_bs = std::move(bs);

src/udp_wrap.h

@@ -158,6 +158,15 @@ class UDPWrap final : public HandleWrap,
               const uv_buf_t& buf,
               const sockaddr* addr,
               unsigned int flags) override;
+  bool using_recvmmsg() {
+    return uv_udp_using_recvmmsg(reinterpret_cast<uv_udp_t*>(&handle_));
+  }
+  void release_buf() {
+    if (mmsg_buf_.base != nullptr) {
+      free(mmsg_buf_.base);
+      mmsg_buf_ = uv_buf_init(nullptr, 0);
+    }
+  }
   ReqWrap<uv_udp_send_t>* CreateSendWrap(size_t msg_size) override;
   void OnSendDone(ReqWrap<uv_udp_send_t>* wrap, int status) override;
 
@@ -189,7 +198,9 @@ class UDPWrap final : public HandleWrap,
             int (*F)(const typename T::HandleType*, sockaddr*, int*)>
   friend void GetSockOrPeerName(const v8::FunctionCallbackInfo<v8::Value>&);
 
-  UDPWrap(Environment* env, v8::Local<v8::Object> object);
+  UDPWrap(Environment* env, v8::Local<v8::Object> object, uint32_t msg_count);
+
+  ~UDPWrap();
 
   static void DoBind(const v8::FunctionCallbackInfo<v8::Value>& args,
                      int family);
@@ -213,7 +224,8 @@ class UDPWrap final : public HandleWrap,
                      unsigned int flags);
 
   uv_udp_t handle_;
-
+  uint32_t msg_count_;
+  uv_buf_t mmsg_buf_;
   bool current_send_has_callback_;
   v8::Local<v8::Object> current_send_req_wrap_;
 };

test/parallel/test-dgram-udp-recvmmsg-close.js

@@ -0,0 +1,30 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const dgram = require('dgram');
+const message_to_send = 'A message to send';
+
+const server = dgram.createSocket({ type: 'udp4', msgCount: 3 });
+const client = dgram.createSocket({ type: 'udp4' });
+
+client.on('close', common.mustCall());
+server.on('close', common.mustCall());
+
+server.on('message', common.mustCall((msg) => {
+  assert.strictEqual(msg.toString(), message_to_send.toString());
+  // The server will release the memory which allocated by handle->alloc_cb
+  server.close();
+  client.close();
+}));
+
+server.on('listening', common.mustCall(() => {
+  for (let i = 0; i < 2; i++) {
+    client.send(message_to_send,
+                0,
+                message_to_send.length,
+                server.address().port,
+                server.address().address);
+  }
+}));
+
+server.bind(0);

test/parallel/test-dgram-udp-recvmmsg.js

@@ -0,0 +1,33 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const dgram = require('dgram');
+const message_to_send = 'A message to send';
+
+const server = dgram.createSocket({ type: 'udp4', msgCount: 3 });
+const client = dgram.createSocket({ type: 'udp4' });
+
+client.on('close', common.mustCall());
+server.on('close', common.mustCall());
+
+let done = 0;
+const count = 2;
+server.on('message', common.mustCall((msg) => {
+  assert.strictEqual(msg.toString(), message_to_send.toString());
+  if (++done === count) {
+    client.close();
+    server.close();
+  }
+}, count));
+
+server.on('listening', common.mustCall(() => {
+  for (let i = 0; i < count; i++) {
+    client.send(message_to_send,
+                0,
+                message_to_send.length,
+                server.address().port,
+                server.address().address);
+  }
+}));
+
+server.bind(0);