// Copyright Joyent, Inc. and other Node contributors.
//
// 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 "tcp_wrap.h"
#ifdef _WIN32
#include <winsock2.h>
#include <ws2tcpip.h>
#endif
#include <cerrno>
#include <cstdlib>
#include "connect_wrap.h"
#include "connection_wrap.h"
#include "env-inl.h"
#include "handle_wrap.h"
#include "node_buffer.h"
#include "node_external_reference.h"
#include "node_internals.h"
#include "permission/permission.h"
#include "stream_base-inl.h"
#include "stream_wrap.h"
#include "util-inl.h"

#ifndef _WIN32
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>
#include <sys/socket.h>
#include <unistd.h>  // dup(), close()
#endif

namespace node {

using v8::Boolean;
using v8::Context;
using v8::EscapableHandleScope;
using v8::Function;
using v8::FunctionCallbackInfo;
using v8::FunctionTemplate;
using v8::Int32;
using v8::Integer;
using v8::Isolate;
using v8::Local;
using v8::MaybeLocal;
using v8::Object;
using v8::String;
using v8::Uint32;
using v8::Value;

MaybeLocal<Object> TCPWrap::Instantiate(Environment* env,
                                        AsyncWrap* parent,
                                        TCPWrap::SocketType type) {
  EscapableHandleScope handle_scope(env->isolate());
  AsyncHooks::DefaultTriggerAsyncIdScope trigger_scope(parent);
  CHECK_EQ(env->tcp_constructor_template().IsEmpty(), false);
  Local<Function> constructor;
  if (!env->tcp_constructor_template()
           ->GetFunction(env->context())
           .ToLocal(&constructor)) {
    return {};
  }
  Local<Value> type_value = Int32::New(env->isolate(), type);
  return handle_scope.EscapeMaybe(
      constructor->NewInstance(env->context(), 1, &type_value));
}

void TCPWrap::Initialize(Local<Object> target,
                         Local<Value> unused,
                         Local<Context> context,
                         void* priv) {
  Environment* env = Environment::GetCurrent(context);
  Isolate* isolate = env->isolate();

  Local<FunctionTemplate> t = env->tcp_constructor_template();
  if (t.IsEmpty()) {
    t = NewFunctionTemplate(isolate, New);
    t->InstanceTemplate()->SetInternalFieldCount(TCPWrap::kInternalFieldCount);

    // Init properties
    t->InstanceTemplate()->Set(FIXED_ONE_BYTE_STRING(isolate, "reading"),
                               Boolean::New(isolate, false));
    t->InstanceTemplate()->Set(env->owner_symbol(), Null(isolate));
    t->InstanceTemplate()->Set(env->onconnection_string(), Null(isolate));

    t->Inherit(LibuvStreamWrap::GetConstructorTemplate(env));

    SetProtoMethod(isolate, t, "open", Open);
    SetProtoMethod(isolate, t, "bind", Bind);
    SetProtoMethod(isolate, t, "listen", Listen);
    SetProtoMethod(isolate, t, "connect", Connect);
    SetProtoMethod(isolate, t, "bind6", Bind6);
    SetProtoMethod(isolate, t, "connect6", Connect6);
    SetProtoMethod(isolate,
                   t,
                   "getsockname",
                   GetSockOrPeerName<TCPWrap, uv_tcp_getsockname>);
    SetProtoMethod(isolate,
                   t,
                   "getpeername",
                   GetSockOrPeerName<TCPWrap, uv_tcp_getpeername>);
    SetProtoMethod(isolate, t, "setNoDelay", SetNoDelay);
    SetProtoMethod(isolate, t, "setKeepAlive", SetKeepAlive);
    SetProtoMethod(isolate, t, "setTypeOfService", SetTypeOfService);
    SetProtoMethod(isolate, t, "getTypeOfService", GetTypeOfService);
    SetProtoMethod(isolate, t, "reset", Reset);

#ifdef _WIN32
    SetProtoMethod(
        isolate, t, "setSimultaneousAccepts", SetSimultaneousAccepts);
#endif

    t->SetClassName(FIXED_ONE_BYTE_STRING(isolate, "TCP"));
    env->set_tcp_constructor_template(t);
  }
  SetConstructorFunction(
      context, target, "TCP", t, SetConstructorFunctionFlag::NONE);

  // Create FunctionTemplate for TCPConnectWrap.
  Local<FunctionTemplate> cwt = AsyncWrap::MakeLazilyInitializedJSTemplate(env);
  SetConstructorFunction(context, target, "TCPConnectWrap", cwt);

  // Define constants
  Local<Object> constants = Object::New(env->isolate());
  NODE_DEFINE_CONSTANT(constants, SOCKET);
  NODE_DEFINE_CONSTANT(constants, SERVER);
  NODE_DEFINE_CONSTANT(constants, UV_TCP_IPV6ONLY);
  NODE_DEFINE_CONSTANT(constants, UV_TCP_REUSEPORT);
  target->Set(context, env->constants_string(), constants).Check();
}

void TCPWrap::RegisterExternalReferences(ExternalReferenceRegistry* registry) {
  registry->Register(New);
  registry->Register(Open);
  registry->Register(Bind);
  registry->Register(Listen);
  registry->Register(Connect);
  registry->Register(Bind6);
  registry->Register(Connect6);

  registry->Register(GetSockOrPeerName<TCPWrap, uv_tcp_getsockname>);
  registry->Register(GetSockOrPeerName<TCPWrap, uv_tcp_getpeername>);
  registry->Register(SetNoDelay);
  registry->Register(SetKeepAlive);
  registry->Register(SetTypeOfService);
  registry->Register(GetTypeOfService);
  registry->Register(Reset);
#ifdef _WIN32
  registry->Register(SetSimultaneousAccepts);
#endif
}

void TCPWrap::New(const FunctionCallbackInfo<Value>& args) {
  // This constructor should not be exposed to public javascript.
  // Therefore we assert that we are not trying to call this as a
  // normal function.
  CHECK(args.IsConstructCall());
  CHECK(args[0]->IsInt32());
  Environment* env = Environment::GetCurrent(args);

  int type_value = args[0].As<Int32>()->Value();
  TCPWrap::SocketType type = static_cast<TCPWrap::SocketType>(type_value);

  ProviderType provider;
  switch (type) {
    case SOCKET:
      provider = PROVIDER_TCPWRAP;
      break;
    case SERVER:
      provider = PROVIDER_TCPSERVERWRAP;
      break;
    default:
      UNREACHABLE();
  }

  new TCPWrap(env, args.This(), provider);
}

TCPWrap::TCPWrap(Environment* env, Local<Object> object, ProviderType provider)
    : ConnectionWrap(env, object, provider) {
  int r = uv_tcp_init(env->event_loop(), &handle_);
  CHECK_EQ(r, 0);  // How do we proxy this error up to javascript?
                   // Suggestion: uv_tcp_init() returns void.
}

void TCPWrap::SetNoDelay(const FunctionCallbackInfo<Value>& args) {
  TCPWrap* wrap;
  ASSIGN_OR_RETURN_UNWRAP(
      &wrap, args.This(), args.GetReturnValue().Set(UV_EBADF));
  int enable = static_cast<int>(args[0]->IsTrue());
  int err = uv_tcp_nodelay(&wrap->handle_, enable);
  args.GetReturnValue().Set(err);
}

void TCPWrap::SetKeepAlive(const FunctionCallbackInfo<Value>& args) {
  TCPWrap* wrap;
  ASSIGN_OR_RETURN_UNWRAP(
      &wrap, args.This(), args.GetReturnValue().Set(UV_EBADF));
  Environment* env = wrap->env();
  int enable;
  if (!args[0]->Int32Value(env->context()).To(&enable)) return;
  unsigned int delay = static_cast<unsigned int>(args[1].As<Uint32>()->Value());
  // interval and count are optional. Fall back to the libuv defaults
  // (1 second, 10 probes) when they are not provided so that callers using
  // the legacy two-argument form of this handle method keep working.
  unsigned int interval = 1;
  unsigned int count = 10;
  if (args[2]->IsUint32()) interval = args[2].As<Uint32>()->Value();
  if (args[3]->IsUint32()) count = args[3].As<Uint32>()->Value();
  int err = uv_tcp_keepalive_ex(&wrap->handle_, enable, delay, interval, count);
  args.GetReturnValue().Set(err);
}

// TODO(amyssnippet): This implementation uses raw setsockopt/getsockopt calls
// as a temporary measure. Upstream support is tracked in
// https://github.com/libuv/libuv/issues/5011.
// Once uv_tcp_set_tos and uv_tcp_get_tos are available in libuv,
// this should be refactored to use those APIs.
void TCPWrap::SetTypeOfService(const FunctionCallbackInfo<Value>& args) {
  TCPWrap* wrap;
  ASSIGN_OR_RETURN_UNWRAP(
      &wrap, args.This(), args.GetReturnValue().Set(UV_EBADF));
  Environment* env = wrap->env();

  int tos = 0;
  if (!args[0]->Int32Value(env->context()).To(&tos)) return;

  uv_os_fd_t fd;
  int err = uv_fileno(reinterpret_cast<uv_handle_t*>(&wrap->handle_), &fd);
  if (err != 0) {
    args.GetReturnValue().Set(err);
    return;
  }

  // 1. Detect the socket family (IPv4 vs IPv6)
  sockaddr_storage storage;
  int addrlen = sizeof(storage);
  int sock_err = uv_tcp_getsockname(
      &wrap->handle_, reinterpret_cast<sockaddr*>(&storage), &addrlen);

  // If we can't determine the family (e.g. closed socket), fail gracefully.
  if (sock_err != 0) {
    args.GetReturnValue().Set(sock_err);
    return;
  }

  // 2. Select the correct protocol level and option name
  int level;
  int option;

  if (storage.ss_family == AF_INET) {
    level = IPPROTO_IP;
    option = IP_TOS;
  } else if (storage.ss_family == AF_INET6) {
    level = IPPROTO_IPV6;
    option = IPV6_TCLASS;
  } else {
    // Unsupported socket family (e.g. AF_UNIX)
    args.GetReturnValue().Set(UV_EINVAL);
    return;
  }

  // 3. Perform the system call (Platform specific casting)
#ifdef _WIN32
  if (setsockopt(reinterpret_cast<::SOCKET>(fd),
                 level,
                 option,
                 reinterpret_cast<const char*>(&tos),
                 static_cast<int>(sizeof(tos))) == 0) {
    args.GetReturnValue().Set(0);
  } else {
    args.GetReturnValue().Set(uv_translate_sys_error(WSAGetLastError()));
  }
#else
  if (setsockopt(fd, level, option, &tos, sizeof(tos)) == 0) {
    args.GetReturnValue().Set(0);
  } else {
    args.GetReturnValue().Set(uv_translate_sys_error(errno));
  }
#endif
}

void TCPWrap::GetTypeOfService(const FunctionCallbackInfo<Value>& args) {
  TCPWrap* wrap;
  ASSIGN_OR_RETURN_UNWRAP(
      &wrap, args.This(), args.GetReturnValue().Set(UV_EBADF));

  uv_os_fd_t fd;
  int err = uv_fileno(reinterpret_cast<uv_handle_t*>(&wrap->handle_), &fd);
  if (err != 0) {
    args.GetReturnValue().Set(err);
    return;
  }

  // Detect socket family explicitly
  sockaddr_storage storage;
  int addrlen = sizeof(storage);
  int sock_err = uv_tcp_getsockname(
      &wrap->handle_, reinterpret_cast<sockaddr*>(&storage), &addrlen);

  int level;
  int option;

  // Select the correct constant based on family
  if (sock_err == 0) {
    if (storage.ss_family == AF_INET) {
      level = IPPROTO_IP;
      option = IP_TOS;
    } else if (storage.ss_family == AF_INET6) {
      level = IPPROTO_IPV6;
      option = IPV6_TCLASS;
    } else {
      // Unknown or unsupported family
      args.GetReturnValue().Set(UV_EINVAL);
      return;
    }
  } else {
    // If we can't determine the family, we can't safely get the TOS
    args.GetReturnValue().Set(sock_err);
    return;
  }

  int tos = 0;

  // Perform the system call with platform-specific casting
#ifdef _WIN32
  int len = sizeof(tos);
  if (getsockopt(reinterpret_cast<::SOCKET>(fd),
                 level,
                 option,
                 reinterpret_cast<char*>(&tos),
                 &len) == 0) {
    args.GetReturnValue().Set(tos);
  } else {
    args.GetReturnValue().Set(uv_translate_sys_error(WSAGetLastError()));
  }
#else
  socklen_t len = sizeof(tos);
  if (getsockopt(fd, level, option, &tos, &len) == 0) {
    args.GetReturnValue().Set(tos);
  } else {
    args.GetReturnValue().Set(uv_translate_sys_error(errno));
  }
#endif
}

#ifdef _WIN32
void TCPWrap::SetSimultaneousAccepts(const FunctionCallbackInfo<Value>& args) {
  TCPWrap* wrap;
  ASSIGN_OR_RETURN_UNWRAP(
      &wrap, args.This(), args.GetReturnValue().Set(UV_EBADF));
  bool enable = args[0]->IsTrue();
  int err = uv_tcp_simultaneous_accepts(&wrap->handle_, enable);
  args.GetReturnValue().Set(err);
}
#endif

void TCPWrap::Open(const FunctionCallbackInfo<Value>& args) {
  TCPWrap* wrap;
  ASSIGN_OR_RETURN_UNWRAP(
      &wrap, args.This(), args.GetReturnValue().Set(UV_EBADF));
  Environment* env = wrap->env();
  int64_t val;
  if (!args[0]->IntegerValue(args.GetIsolate()->GetCurrentContext()).To(&val))
    return;
  int fd = static_cast<int>(val);

  // Adopting an existing descriptor gives access to whatever it is connected
  // to, so, like bind(), listen() and connect(), it requires the net
  // permission.
  if (!IsProcessStdioOrIPCChannel(env, fd)) {
    THROW_IF_INSUFFICIENT_PERMISSIONS(
        env, permission::PermissionScope::kNet, "");
  }

  int err = uv_tcp_open(&wrap->handle_, fd);

  if (err == 0) wrap->set_fd(fd);

  args.GetReturnValue().Set(err);
}

BaseObject::TransferMode TCPWrap::GetTransferMode() const {
  // Only a live handle that is not already being torn down can be transferred.
  // Higher-level guards (no buffered reads, no pending writes) are enforced by
  // the JS net.Socket/net.Server layer before a handle reaches here.
  if (!HandleWrap::IsAlive(this) || IsHandleClosing())
    return TransferMode::kDisallowCloneAndTransfer;
  return TransferMode::kTransferable;
}

std::unique_ptr<worker::TransferData> TCPWrap::TransferForMessaging() {
  CHECK_NE(GetTransferMode(), TransferMode::kDisallowCloneAndTransfer);

  uv_os_fd_t fd;
  if (uv_fileno(reinterpret_cast<uv_handle_t*>(&handle_), &fd) != 0) return {};

#ifdef _WIN32
  // A socket that is already associated with an IOCP cannot be associated with
  // another one. Create a same-process duplicate that is not associated with
  // any IOCP yet; uv_tcp_open() will associate it with the receiving loop.
  WSAPROTOCOL_INFOW protocol_info;
  uv_os_sock_t source_socket = reinterpret_cast<uv_os_sock_t>(fd);
  if (WSADuplicateSocketW(
          source_socket, GetCurrentProcessId(), &protocol_info) != 0) {
    return {};
  }
  uv_os_sock_t duplicate = WSASocketW(FROM_PROTOCOL_INFO,
                                      FROM_PROTOCOL_INFO,
                                      FROM_PROTOCOL_INFO,
                                      &protocol_info,
                                      0,
                                      WSA_FLAG_OVERLAPPED);
  if (duplicate == static_cast<uv_os_sock_t>(-1)) return {};
#else
  // Unix threads share the descriptor table, so dup() creates an independent
  // reference to the same socket for the receiving event loop.
  uv_os_sock_t duplicate = dup(fd);
  if (duplicate < 0) return {};
#endif

  SocketType type =
      provider_type() == ProviderType::PROVIDER_TCPSERVERWRAP ? SERVER : SOCKET;

  // Stop watching the original socket and tear down the source handle. The
  // duplicate keeps the underlying socket alive until the destination adopts
  // it, or until TransferData is destroyed if the message is not delivered.
  Close();

  return std::make_unique<TransferData>(duplicate, type);
}

TCPWrap::TransferData::~TransferData() {
#ifdef _WIN32
  if (socket_ != static_cast<uv_os_sock_t>(-1))
    CHECK_EQ(0, closesocket(socket_));
#else
  if (socket_ >= 0) {
    uv_fs_t req;
    CHECK_EQ(0, uv_fs_close(nullptr, &req, socket_, nullptr));
    uv_fs_req_cleanup(&req);
  }
#endif
}

BaseObjectPtr<BaseObject> TCPWrap::TransferData::Deserialize(
    Environment* env,
    Local<Context> context,
    std::unique_ptr<worker::TransferData> self) {
  // Construct a fresh TCPWrap in the receiving Environment. We cannot use
  // TCPWrap::Instantiate() here because it requires a parent AsyncWrap to
  // establish the async_hooks trigger id, and a deserialized handle has none.
  if (env->tcp_constructor_template().IsEmpty()) return {};
  Local<Function> constructor;
  if (!env->tcp_constructor_template()->GetFunction(context).ToLocal(
          &constructor)) {
    return {};
  }
  Local<Value> type_arg = Int32::New(env->isolate(), type_);
  Local<Object> obj;
  if (!constructor->NewInstance(context, 1, &type_arg).ToLocal(&obj)) return {};

  TCPWrap* wrap = BaseObject::Unwrap<TCPWrap>(obj);
  if (wrap == nullptr) return {};

  if (uv_tcp_open(&wrap->handle_, socket_) != 0) return {};

#ifdef _WIN32
  socket_ = static_cast<uv_os_sock_t>(-1);
#else
  wrap->set_fd(socket_);
  socket_ = -1;
#endif
  return BaseObjectPtr<BaseObject>(wrap);
}

template <typename T>
void TCPWrap::Bind(const FunctionCallbackInfo<Value>& args,
                   int family,
                   int (*uv_ip_addr)(const char* ip_address,
                                     int port,
                                     T* addr)) {
  TCPWrap* wrap;
  ASSIGN_OR_RETURN_UNWRAP(
      &wrap, args.This(), args.GetReturnValue().Set(UV_EBADF));
  Environment* env = wrap->env();

  THROW_IF_INSUFFICIENT_PERMISSIONS(env, permission::PermissionScope::kNet, "");

  node::Utf8Value ip_address(env->isolate(), args[0]);
  int port;
  unsigned int flags = 0;
  if (!args[1]->Int32Value(env->context()).To(&port)) return;
  if (args.Length() >= 3 && args[2]->IsUint32()) {
    if (!args[2]->Uint32Value(env->context()).To(&flags)) return;
    // Can not set IPV6 flags on IPV4 socket
    if (family == AF_INET) {
      flags &= ~UV_TCP_IPV6ONLY;
    }
  }

  T addr;
  int err = uv_ip_addr(*ip_address, port, &addr);

  if (err == 0) {
    err = uv_tcp_bind(
        &wrap->handle_, reinterpret_cast<const sockaddr*>(&addr), flags);
  }
  args.GetReturnValue().Set(err);
}

void TCPWrap::Bind(const FunctionCallbackInfo<Value>& args) {
  Bind<sockaddr_in>(args, AF_INET, uv_ip4_addr);
}

void TCPWrap::Bind6(const FunctionCallbackInfo<Value>& args) {
  Bind<sockaddr_in6>(args, AF_INET6, uv_ip6_addr);
}

void TCPWrap::Listen(const FunctionCallbackInfo<Value>& args) {
  TCPWrap* wrap;
  ASSIGN_OR_RETURN_UNWRAP(
      &wrap, args.This(), args.GetReturnValue().Set(UV_EBADF));
  Environment* env = wrap->env();
  int backlog;
  if (!args[0]->Int32Value(env->context()).To(&backlog)) return;

  THROW_IF_INSUFFICIENT_PERMISSIONS(env, permission::PermissionScope::kNet, "");

  int err = uv_listen(
      reinterpret_cast<uv_stream_t*>(&wrap->handle_), backlog, OnConnection);
  args.GetReturnValue().Set(err);
}

void TCPWrap::Connect(const FunctionCallbackInfo<Value>& args) {
  Connect<sockaddr_in>(args, uv_ip4_addr);
}

void TCPWrap::Connect6(const FunctionCallbackInfo<Value>& args) {
  Connect<sockaddr_in6>(args, uv_ip6_addr);
}

template <typename T>
void TCPWrap::Connect(const FunctionCallbackInfo<Value>& args,
                      int (*uv_ip_addr)(const char* ip_address,
                                        int port,
                                        T* addr)) {
  Environment* env = Environment::GetCurrent(args);

  TCPWrap* wrap;
  ASSIGN_OR_RETURN_UNWRAP(
      &wrap, args.This(), args.GetReturnValue().Set(UV_EBADF));

  CHECK(args[0]->IsObject());
  CHECK(args[1]->IsString());

  int port;
  if (!args[2]->Int32Value(env->context()).To(&port)) return;

  Local<Object> req_wrap_obj = args[0].As<Object>();
  node::Utf8Value ip_address(env->isolate(), args[1]);

  ERR_ACCESS_DENIED_IF_INSUFFICIENT_PERMISSIONS(
      env, permission::PermissionScope::kNet, ip_address.ToStringView(), args);

  T addr;
  int err = uv_ip_addr(*ip_address, port, &addr);

  if (err == 0) {
    AsyncHooks::DefaultTriggerAsyncIdScope trigger_scope(wrap);
    ConnectWrap* req_wrap =
        new ConnectWrap(env, req_wrap_obj, AsyncWrap::PROVIDER_TCPCONNECTWRAP);
    err = req_wrap->Dispatch(uv_tcp_connect,
                             &wrap->handle_,
                             reinterpret_cast<const sockaddr*>(&addr),
                             AfterConnect);
    if (err) {
      delete req_wrap;
    } else {
      CHECK(args[2]->Uint32Value(env->context()).IsJust());
      uint32_t port;
      if (!args[2]->Uint32Value(env->context()).To(&port)) {
        return;
      }
      TRACE_EVENT_NESTABLE_ASYNC_BEGIN2(TRACING_CATEGORY_NODE2(net, native),
                                        "connect",
                                        req_wrap,
                                        "ip",
                                        TRACE_STR_COPY(*ip_address),
                                        "port",
                                        port);
    }
  }

  args.GetReturnValue().Set(err);
}
void TCPWrap::Reset(const FunctionCallbackInfo<Value>& args) {
  TCPWrap* wrap;
  ASSIGN_OR_RETURN_UNWRAP(
      &wrap, args.This(), args.GetReturnValue().Set(UV_EBADF));

  int err = wrap->Reset(args[0]);

  args.GetReturnValue().Set(err);
}

int TCPWrap::Reset(Local<Value> close_callback) {
  if (state_ != kInitialized) return 0;

  int err = uv_tcp_close_reset(&handle_, OnClose);
  state_ = kClosing;
  if (!err & !close_callback.IsEmpty() && close_callback->IsFunction() &&
      !persistent().IsEmpty()) {
    object()
        ->Set(env()->context(), env()->handle_onclose_symbol(), close_callback)
        .Check();
  }
  return err;
}

// also used by udp_wrap.cc
MaybeLocal<Object> AddressToJS(Environment* env,
                               const sockaddr* addr,
                               Local<Object> info) {
  EscapableHandleScope scope(env->isolate());
  char ip[INET6_ADDRSTRLEN + UV_IF_NAMESIZE];
  const sockaddr_in* a4;
  const sockaddr_in6* a6;

  int port;

  if (info.IsEmpty()) {
    info = Object::New(env->isolate());
  }

  switch (addr->sa_family) {
    case AF_INET6:
      a6 = reinterpret_cast<const sockaddr_in6*>(addr);
      uv_inet_ntop(AF_INET6, &a6->sin6_addr, ip, sizeof ip);
      // Add an interface identifier to a link local address.
      if (IN6_IS_ADDR_LINKLOCAL(&a6->sin6_addr) && a6->sin6_scope_id > 0) {
        const size_t addrlen = strlen(ip);
        CHECK_LT(addrlen, sizeof(ip));
        ip[addrlen] = '%';
        size_t scopeidlen = sizeof(ip) - addrlen - 1;
        CHECK_GE(scopeidlen, UV_IF_NAMESIZE);
        const int r =
            uv_if_indextoiid(a6->sin6_scope_id, ip + addrlen + 1, &scopeidlen);
        if (r) {
          env->ThrowUVException(r, "uv_if_indextoiid");
          return {};
        }
      }
      port = ntohs(a6->sin6_port);
      if (info->Set(env->context(),
                    env->address_string(),
                    OneByteString(env->isolate(), ip))
              .IsNothing() ||
          info->Set(env->context(), env->family_string(), env->ipv6_string())
              .IsNothing() ||
          info->Set(env->context(),
                    env->port_string(),
                    Integer::New(env->isolate(), port))
              .IsNothing()) {
        return {};
      }
      break;

    case AF_INET:
      a4 = reinterpret_cast<const sockaddr_in*>(addr);
      uv_inet_ntop(AF_INET, &a4->sin_addr, ip, sizeof ip);
      port = ntohs(a4->sin_port);
      if (info->Set(env->context(),
                    env->address_string(),
                    OneByteString(env->isolate(), ip))
              .IsNothing() ||
          info->Set(env->context(), env->family_string(), env->ipv4_string())
              .IsNothing() ||
          info->Set(env->context(),
                    env->port_string(),
                    Integer::New(env->isolate(), port))
              .IsNothing()) {
        return {};
      }
      break;

    default:
      if (info->Set(env->context(),
                    env->address_string(),
                    String::Empty(env->isolate()))
              .IsNothing()) {
        return {};
      }
  }

  return scope.Escape(info);
}

}  // namespace node

NODE_BINDING_CONTEXT_AWARE_INTERNAL(tcp_wrap, node::TCPWrap::Initialize)
NODE_BINDING_EXTERNAL_REFERENCE(tcp_wrap,
                                node::TCPWrap::RegisterExternalReferences)