Add a no_ibv

CMakeLists.txt

@@ -119,6 +119,10 @@ if(MLX_BUILD_METAL)
     COMMAND zsh "-c" "/usr/bin/xcrun -sdk macosx --show-sdk-version"
     OUTPUT_VARIABLE MACOS_SDK_VERSION
     OUTPUT_STRIP_TRAILING_WHITESPACE COMMAND_ERROR_IS_FATAL ANY)
+  execute_process(
+    COMMAND zsh "-c" "/usr/bin/xcrun -sdk macosx --show-sdk-path"
+    OUTPUT_VARIABLE CMAKE_OSX_SYSROOT
+    OUTPUT_STRIP_TRAILING_WHITESPACE COMMAND_ERROR_IS_FATAL ANY)
 
   if(${MACOS_SDK_VERSION} LESS 14.0)
     message(

mlx/distributed/CMakeLists.txt

@@ -4,6 +4,11 @@ target_sources(
           ${CMAKE_CURRENT_SOURCE_DIR}/ops.cpp
           ${CMAKE_CURRENT_SOURCE_DIR}/distributed.cpp)
 
+if(MLX_BUILD_CPU AND NOT WIN32)
+  target_sources(mlx PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/utils.cpp)
+endif()
+
 add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/mpi)
 add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/ring)
 add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/nccl)
+add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/ibv)

mlx/distributed/distributed.cpp

@@ -5,6 +5,7 @@
 #include "mlx/backend/cuda/cuda.h"
 #include "mlx/distributed/distributed.h"
 #include "mlx/distributed/distributed_impl.h"
+#include "mlx/distributed/ibv/ibv.h"
 #include "mlx/distributed/mpi/mpi.h"
 #include "mlx/distributed/nccl/nccl.h"
 #include "mlx/distributed/ring/ring.h"
@@ -102,7 +103,8 @@ class EmptyGroup : public GroupImpl {
 } // namespace detail
 
 bool is_available() {
-  return mpi::is_available() || ring::is_available() || nccl::is_available();
+  return mpi::is_available() || ring::is_available() || nccl::is_available() ||
+      ibv::is_available();
 }
 
 int Group::rank() const {
@@ -135,6 +137,8 @@ Group init(bool strict /* = false */, const std::string& bk /* = "any" */) {
     group = ring::init(strict);
   } else if (bk == "nccl") {
     group = nccl::init(strict);
+  } else if (bk == "ibv") {
+    group = ibv::init(strict);
   } else if (bk == "any") {
     if (mlx::core::cu::is_available()) {
       group = nccl::init(false);
@@ -148,13 +152,17 @@ Group init(bool strict /* = false */, const std::string& bk /* = "any" */) {
       group = mpi::init(false);
       bk_ = "mpi";
     }
+    if (group == nullptr) {
+      group = ibv::init(false);
+      bk_ = "ibv";
+    }
     if (group == nullptr && strict) {
       throw std::runtime_error("[distributed] Couldn't initialize any backend");
     }
   } else {
     std::ostringstream msg;
-    msg << "[distributed] The only valid values for backend are 'any', 'mpi' "
+    msg << "[distributed] The only valid values for backend are 'any', 'mpi', 'nccl', "
-        << "and 'ring' but '" << bk << "' was provided.";
+        << "'ibv' and 'ring' but '" << bk << "' was provided.";
     throw std::invalid_argument(msg.str());
   }
 

mlx/distributed/ibv/CMakeLists.txt

@@ -0,0 +1,8 @@
+if(MLX_BUILD_CPU
+   AND ${CMAKE_SYSTEM_NAME} MATCHES "Darwin"
+   AND MACOS_SDK_VERSION GREATER_EQUAL 26.2)
+  target_sources(mlx PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/ibv.cpp)
+  target_link_libraries(mlx PRIVATE rdma)
+else()
+  target_sources(mlx PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/no_ibv.cpp)
+endif()

mlx/distributed/ibv/ibv.h

@@ -0,0 +1,12 @@
+// Copyright © 2025 Apple Inc.
+
+#include "mlx/distributed/distributed.h"
+
+namespace mlx::core::distributed::ibv {
+
+using GroupImpl = mlx::core::distributed::detail::GroupImpl;
+
+bool is_available();
+std::shared_ptr<GroupImpl> init(bool strict = false);
+
+} // namespace mlx::core::distributed::ibv

mlx/distributed/ibv/no_ibv.cpp

@@ -0,0 +1,20 @@
+// Copyright © 2025 Apple Inc.
+
+#include "mlx/distributed/ibv/ibv.h"
+
+namespace mlx::core::distributed::ibv {
+
+using GroupImpl = mlx::core::distributed::detail::GroupImpl;
+
+bool is_available() {
+  return false;
+}
+
+std::shared_ptr<GroupImpl> init(bool strict /* = false */) {
+  if (strict) {
+    throw std::runtime_error("Cannot initialize ibv distributed backend.");
+  }
+  return nullptr;
+}
+
+} // namespace mlx::core::distributed::ibv

mlx/distributed/reduction_ops.h

@@ -0,0 +1,38 @@
+// Copyright © 2025 Apple Inc.
+
+namespace mlx::core::distributed::detail {
+
+template <typename T>
+struct SumOp {
+  void operator()(const T* input, T* output, size_t N) const {
+    while (N-- > 0) {
+      *output += *input;
+      input++;
+      output++;
+    }
+  }
+};
+
+template <typename T>
+struct MaxOp {
+  void operator()(const T* input, T* output, size_t N) const {
+    while (N-- > 0) {
+      *output = std::max(*output, *input);
+      input++;
+      output++;
+    }
+  }
+};
+
+template <typename T>
+struct MinOp {
+  void operator()(const T* input, T* output, size_t N) const {
+    while (N-- > 0) {
+      *output = std::min(*output, *input);
+      input++;
+      output++;
+    }
+  }
+};
+
+} // namespace mlx::core::distributed::detail

mlx/distributed/ring/ring.cpp

@@ -1,9 +1,6 @@
 // Copyright © 2024 Apple Inc.
 
-#include <arpa/inet.h>
 #include <fcntl.h>
-#include <netdb.h>
-#include <netinet/in.h>
 #include <netinet/tcp.h>
 #include <sys/socket.h>
 #include <unistd.h>
@@ -22,6 +19,8 @@
 #include "mlx/backend/cpu/encoder.h"
 #include "mlx/distributed/distributed.h"
 #include "mlx/distributed/distributed_impl.h"
+#include "mlx/distributed/reduction_ops.h"
+#include "mlx/distributed/utils.h"
 #include "mlx/threadpool.h"
 
 #ifndef SOL_TCP
@@ -94,6 +93,7 @@ constexpr const size_t ALL_SUM_SIZE = 8 * 1024 * 1024;
 constexpr const size_t ALL_SUM_BUFFERS = 2;
 constexpr const int CONN_ATTEMPTS = 5;
 constexpr const int CONN_WAIT = 1000;
+constexpr const char* RING_TAG = "[ring]";
 
 using GroupImpl = mlx::core::distributed::detail::GroupImpl;
 using json = nlohmann::json;
@@ -296,55 +296,6 @@ class CommunicationThreads {
   std::unordered_map<int, SocketThread> threads_;
 };
 
-struct address_t {
-  sockaddr_storage addr;
-  socklen_t len;
-
-  const sockaddr* get() const {
-    return (struct sockaddr*)&addr;
-  }
-};
-
-/**
- * Parse a sockaddr from an ip and port provided as strings.
- */
-address_t parse_address(const std::string& ip, const std::string& port) {
-  struct addrinfo hints, *res;
-  memset(&hints, 0, sizeof(hints));
-  hints.ai_family = AF_UNSPEC;
-  hints.ai_socktype = SOCK_STREAM;
-
-  int status = getaddrinfo(ip.c_str(), port.c_str(), &hints, &res);
-  if (status != 0) {
-    std::ostringstream msg;
-    msg << "Can't parse address " << ip << ":" << port;
-    throw std::runtime_error(msg.str());
-  }
-
-  address_t result;
-  memcpy(&result.addr, res->ai_addr, res->ai_addrlen);
-  result.len = res->ai_addrlen;
-  freeaddrinfo(res);
-
-  return result;
-}
-
-/**
- * Parse a sockaddr provided as an <ip>:<port> string.
- */
-address_t parse_address(const std::string& ip_port) {
-  auto colon = ip_port.find(":");
-  if (colon == std::string::npos) {
-    std::ostringstream msg;
-    msg << "Can't parse address " << ip_port;
-    throw std::runtime_error(msg.str());
-  }
-  std::string ip(ip_port.begin(), ip_port.begin() + colon);
-  std::string port(ip_port.begin() + colon + 1, ip_port.end());
-
-  return parse_address(ip, port);
-}
-
 /**
  * Load all addresses from the json hostfile. The hostfile is a list of
  * addresses in order of rank. For each rank there can be many addresses so
@@ -357,15 +308,15 @@ address_t parse_address(const std::string& ip_port) {
  *    ["ip3:5000", "ip3:5001"],
  *  ]
  */
-std::vector<std::vector<address_t>> load_nodes(const char* hostfile) {
+std::vector<std::vector<detail::address_t>> load_nodes(const char* hostfile) {
-  std::vector<std::vector<address_t>> nodes;
+  std::vector<std::vector<detail::address_t>> nodes;
   std::ifstream f(hostfile);
 
   json hosts = json::parse(f);
   for (auto& h : hosts) {
-    std::vector<address_t> host;
+    std::vector<detail::address_t> host;
     for (auto& ips : h) {
-      host.push_back(parse_address(ips.get<std::string>()));
+      host.push_back(std::move(detail::parse_address(ips.get<std::string>())));
     }
     nodes.push_back(std::move(host));
   }
@@ -377,73 +328,15 @@ std::vector<std::vector<address_t>> load_nodes(const char* hostfile) {
  * Create a socket and accept one connection for each of the provided
  * addresses.
  */
-std::vector<int> accept_connections(const std::vector<address_t>& addresses) {
+std::vector<int> accept_connections(
+    const std::vector<detail::address_t>& addresses) {
   std::vector<int> sockets;
   int success;
 
   for (auto& address : addresses) {
-    // Create the socket to wait for connections from the peers
+    detail::TCPSocket socket(RING_TAG);
-    int sock = socket(AF_INET, SOCK_STREAM, 0);
+    socket.listen(RING_TAG, address);
-    if (sock < 0) {
+    sockets.push_back(socket.accept(RING_TAG).detach());
-      std::ostringstream msg;
-      msg << "[ring] Couldn't create socket (error: " << errno << ")";
-      throw std::runtime_error(msg.str());
-    }
-
-    // Make sure we can launch immediately after shutdown by setting the
-    // reuseaddr option so that we don't get address already in use errors
-    int enable = 1;
-    success = setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(int));
-    if (success < 0) {
-      shutdown(sock, 2);
-      close(sock);
-      std::ostringstream msg;
-      msg << "[ring] Couldn't enable reuseaddr (error: " << errno << ")";
-      throw std::runtime_error(msg.str());
-    }
-    success = setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &enable, sizeof(int));
-    if (success < 0) {
-      shutdown(sock, 2);
-      close(sock);
-      std::ostringstream msg;
-      msg << "[ring] Couldn't enable reuseport (error: " << errno << ")";
-      throw std::runtime_error(msg.str());
-    }
-
-    // Bind the socket to the address and port
-    success = bind(sock, address.get(), address.len);
-    if (success < 0) {
-      shutdown(sock, 2);
-      close(sock);
-      std::ostringstream msg;
-      msg << "[ring] Couldn't bind socket (error: " << errno << ")";
-      throw std::runtime_error(msg.str());
-    }
-
-    // Wait for connections
-    success = listen(sock, 0);
-    if (success < 0) {
-      shutdown(sock, 2);
-      close(sock);
-      std::ostringstream msg;
-      msg << "[ring] Couldn't listen (error: " << errno << ")";
-      throw std::runtime_error(msg.str());
-    }
-
-    int peer_socket = accept(sock, nullptr, nullptr);
-    if (peer_socket < 0) {
-      shutdown(sock, 2);
-      close(sock);
-      std::ostringstream msg;
-      msg << "[ring] Accept failed (error: " << errno << ")";
-      throw std::runtime_error(msg.str());
-    }
-
-    // Close the listening socket
-    shutdown(sock, 2);
-    close(sock);
-
-    sockets.push_back(peer_socket);
   }
 
   return sockets;
@@ -454,93 +347,42 @@ std::vector<int> accept_connections(const std::vector<address_t>& addresses) {
  * provided addresses.
  */
 std::vector<int> make_connections(
-    const std::vector<address_t>& addresses,
+    const std::vector<detail::address_t>& addresses,
     bool verbose) {
   std::vector<int> sockets;
   int success;
 
   for (auto& address : addresses) {
-    int sock;
+    sockets.push_back(detail::TCPSocket::connect(
-
+                          RING_TAG,
-    // Attempt to connect to the peer CONN_ATTEMPTS times with exponential
+                          address,
-    // backoff. TODO: Do we need that?
+                          CONN_ATTEMPTS,
-    for (int attempt = 0; attempt < CONN_ATTEMPTS; attempt++) {
+                          CONN_WAIT,
-      // Create the socket
+                          [verbose](int attempt, int wait) {
-      sock = socket(AF_INET, SOCK_STREAM, 0);
-      if (sock < 0) {
-        std::ostringstream msg;
-        msg << "[ring] Couldn't create socket (error: " << errno << ")";
-        throw std::runtime_error(msg.str());
-      }
-
-      if (attempt > 0) {
-        int wait = (1 << (attempt - 1)) * CONN_WAIT;
                             log_info(
                                 verbose,
                                 "Attempt",
                                 attempt,
-            "wait",
+                                "waiting",
                                 wait,
                                 "ms (error:",
                                 errno,
                                 ")");
-        std::this_thread::sleep_for(std::chrono::milliseconds(wait));
+                          })
-      }
+                          .detach());
-
-      success = connect(sock, address.get(), address.len);
-      if (success == 0) {
-        break;
-      }
-    }
-    if (success < 0) {
-      std::ostringstream msg;
-      msg << "[ring] Couldn't connect (error: " << errno << ")";
-      throw std::runtime_error(msg.str());
-    }
-
-    sockets.push_back(sock);
   }
 
   return sockets;
 }
-template <typename T>
-struct SumOp {
-  void operator()(const T* input, T* output, size_t N) {
-    while (N-- > 0) {
-      *output += *input;
-      input++;
-      output++;
-    }
-  }
-};
-
-template <typename T>
-struct MaxOp {
-  void operator()(const T* input, T* output, size_t N) {
-    while (N-- > 0) {
-      *output = std::max(*output, *input);
-      input++;
-      output++;
-    }
-  }
-};
-
-template <typename T>
-struct MinOp {
-  void operator()(const T* input, T* output, size_t N) {
-    while (N-- > 0) {
-      *output = std::min(*output, *input);
-      input++;
-      output++;
-    }
-  }
-};
 
 } // namespace
 
 class RingGroup : public GroupImpl {
  public:
-  RingGroup(int rank, std::vector<std::vector<address_t>> nodes, bool verbose)
+  RingGroup(
+      int rank,
+      std::vector<std::vector<detail::address_t>> nodes,
+      bool verbose)
       : rank_(rank), verbose_(verbose), pool_(0) {
     if (rank_ > 0 && rank_ >= nodes.size()) {
       throw std::runtime_error(
@@ -633,17 +475,17 @@ class RingGroup : public GroupImpl {
 
   void all_sum(const array& input, array& output, Stream stream) override {
     SWITCH_TYPE(
-        output, all_reduce<T, SumOp<T>>(input, output, stream, SumOp<T>()));
+        output, all_reduce<T>(input, output, stream, detail::SumOp<T>()));
   }
 
   void all_max(const array& input, array& output, Stream stream) override {
     SWITCH_TYPE(
-        output, all_reduce<T, MaxOp<T>>(input, output, stream, MaxOp<T>()));
+        output, all_reduce<T>(input, output, stream, detail::MaxOp<T>()));
   }
 
   void all_min(const array& input, array& output, Stream stream) override {
     SWITCH_TYPE(
-        output, all_reduce<T, MinOp<T>>(input, output, stream, MinOp<T>()));
+        output, all_reduce<T>(input, output, stream, detail::MinOp<T>()));
   }
 
   std::shared_ptr<GroupImpl> split(int color, int key = -1) override {

mlx/distributed/utils.cpp

@@ -0,0 +1,203 @@
+// Copyright © 2025 Apple Inc.
+
+#include <netdb.h>
+#include <unistd.h>
+#include <sstream>
+#include <thread>
+
+#include "mlx/distributed/utils.h"
+
+namespace mlx::core::distributed::detail {
+
+/**
+ * Parse a sockaddr from an ip and port provided as strings.
+ */
+address_t parse_address(const std::string& ip, const std::string& port) {
+  struct addrinfo hints, *res;
+  memset(&hints, 0, sizeof(hints));
+  hints.ai_family = AF_UNSPEC;
+  hints.ai_socktype = SOCK_STREAM;
+
+  int status = getaddrinfo(ip.c_str(), port.c_str(), &hints, &res);
+  if (status != 0) {
+    std::ostringstream msg;
+    msg << "Can't parse address " << ip << ":" << port;
+    throw std::runtime_error(msg.str());
+  }
+
+  address_t result;
+  memcpy(&result.addr, res->ai_addr, res->ai_addrlen);
+  result.len = res->ai_addrlen;
+  freeaddrinfo(res);
+
+  return result;
+}
+
+/**
+ * Parse a sockaddr provided as an <ip>:<port> string.
+ */
+address_t parse_address(const std::string& ip_port) {
+  auto colon = ip_port.find(":");
+  if (colon == std::string::npos) {
+    std::ostringstream msg;
+    msg << "Can't parse address " << ip_port;
+    throw std::runtime_error(msg.str());
+  }
+  std::string ip(ip_port.begin(), ip_port.begin() + colon);
+  std::string port(ip_port.begin() + colon + 1, ip_port.end());
+
+  return parse_address(ip, port);
+}
+
+TCPSocket::TCPSocket(const char* tag) {
+  sock_ = socket(AF_INET, SOCK_STREAM, 0);
+  if (sock_ < 0) {
+    std::ostringstream msg;
+    msg << tag << " Couldn't create socket (error: " << errno << ")";
+    throw std::runtime_error(msg.str());
+  }
+}
+
+TCPSocket::TCPSocket(TCPSocket&& s) {
+  sock_ = s.sock_;
+  s.sock_ = -1;
+}
+
+TCPSocket& TCPSocket::operator=(TCPSocket&& s) {
+  if (this != &s) {
+    sock_ = s.sock_;
+    s.sock_ = -1;
+  }
+  return *this;
+}
+
+TCPSocket::TCPSocket(int s) : sock_(s) {}
+
+TCPSocket::~TCPSocket() {
+  if (sock_ > 0) {
+    shutdown(sock_, 2);
+    close(sock_);
+  }
+}
+
+int TCPSocket::detach() {
+  int s = sock_;
+  sock_ = -1;
+  return s;
+}
+
+void TCPSocket::listen(const char* tag, const address_t& addr) {
+  int success;
+
+  // Make sure we can launch immediately after shutdown by setting the
+  // reuseaddr option so that we don't get address already in use errors
+  int enable = 1;
+  success = setsockopt(sock_, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(int));
+  if (success < 0) {
+    std::ostringstream msg;
+    msg << tag << " Couldn't enable reuseaddr (error: " << errno << ")";
+    throw std::runtime_error(msg.str());
+  }
+  success = setsockopt(sock_, SOL_SOCKET, SO_REUSEPORT, &enable, sizeof(int));
+  if (success < 0) {
+    std::ostringstream msg;
+    msg << tag << " Couldn't enable reuseport (error: " << errno << ")";
+    throw std::runtime_error(msg.str());
+  }
+
+  // Bind the socket to the address and port
+  success = bind(sock_, addr.get(), addr.len);
+  if (success < 0) {
+    std::ostringstream msg;
+    msg << tag << " Couldn't bind socket (error: " << errno << ")";
+    throw std::runtime_error(msg.str());
+  }
+
+  // Prepare waiting for connections
+  success = ::listen(sock_, 0);
+  if (success < 0) {
+    std::ostringstream msg;
+    msg << tag << " Couldn't listen (error: " << errno << ")";
+    throw std::runtime_error(msg.str());
+  }
+}
+
+TCPSocket TCPSocket::accept(const char* tag) {
+  int peer = ::accept(sock_, nullptr, nullptr);
+  if (peer < 0) {
+    std::ostringstream msg;
+    msg << tag << " Accept failed (error: " << errno << ")";
+    throw std::runtime_error(msg.str());
+  }
+
+  return TCPSocket(peer);
+}
+
+void TCPSocket::send(const char* tag, const void* data, size_t len) {
+  while (len > 0) {
+    auto n = ::send(sock_, data, len, 0);
+    if (n <= 0) {
+      std::ostringstream msg;
+      msg << tag << " Send failed with errno=" << errno;
+      throw std::runtime_error(msg.str());
+    }
+    len -= n;
+    data = static_cast<const char*>(data) + n;
+  }
+}
+
+void TCPSocket::recv(const char* tag, void* data, size_t len) {
+  while (len > 0) {
+    auto n = ::recv(sock_, data, len, 0);
+    if (n <= 0) {
+      std::ostringstream msg;
+      msg << tag << " Recv failed with errno=" << errno;
+      throw std::runtime_error(msg.str());
+    }
+    len -= n;
+    data = static_cast<char*>(data) + n;
+  }
+}
+
+TCPSocket TCPSocket::connect(
+    const char* tag,
+    const address_t& addr,
+    int num_retries,
+    int wait,
+    std::function<void(int, int)> cb) {
+  int sock, success;
+
+  // Attempt to connect `num_retries` times with exponential backoff.
+  for (int attempt = 0; attempt < num_retries; attempt++) {
+    // Create the socket
+    sock = socket(AF_INET, SOCK_STREAM, 0);
+    if (sock < 0) {
+      std::ostringstream msg;
+      msg << tag << " Couldn't create socket to connect (error: " << errno
+          << ")";
+      throw std::runtime_error(msg.str());
+    }
+
+    success = ::connect(sock, addr.get(), addr.len);
+    if (success == 0) {
+      break;
+    }
+
+    cb(attempt, wait);
+    if (wait > 0) {
+      std::this_thread::sleep_for(std::chrono::milliseconds(wait));
+    }
+
+    wait <<= 1;
+  }
+
+  if (success < 0) {
+    std::ostringstream msg;
+    msg << tag << " Couldn't connect (error: " << errno << ")";
+    throw std::runtime_error(msg.str());
+  }
+
+  return TCPSocket(sock);
+}
+
+} // namespace mlx::core::distributed::detail

mlx/distributed/utils.h

@@ -0,0 +1,65 @@
+// Copyright © 2025 Apple Inc.
+
+#pragma once
+
+#include <sys/socket.h>
+
+namespace mlx::core::distributed::detail {
+
+struct address_t {
+  sockaddr_storage addr;
+  socklen_t len;
+
+  const sockaddr* get() const {
+    return (struct sockaddr*)&addr;
+  }
+};
+
+/**
+ * Parse a sockaddr from an ip and port provided as strings.
+ */
+address_t parse_address(const std::string& ip, const std::string& port);
+
+/**
+ * Parse a sockaddr provided as an <ip>:<port> string.
+ */
+address_t parse_address(const std::string& ip_port);
+
+/**
+ * Small wrapper over a TCP socket to simplify initiating connections.
+ */
+class TCPSocket {
+ public:
+  TCPSocket(const char* tag);
+  TCPSocket(const TCPSocket&) = delete;
+  TCPSocket& operator=(const TCPSocket&) = delete;
+  TCPSocket(TCPSocket&& s);
+  TCPSocket& operator=(TCPSocket&&);
+  ~TCPSocket();
+
+  void listen(const char* tag, const address_t& addr);
+  TCPSocket accept(const char* tag);
+
+  void send(const char* tag, const void* data, size_t len);
+  void recv(const char* tag, void* data, size_t len);
+
+  int detach();
+
+  operator int() const {
+    return sock_;
+  }
+
+  static TCPSocket connect(
+      const char* tag,
+      const address_t& addr,
+      int num_retries = 1,
+      int wait = 0,
+      std::function<void(int, int)> cb = nullptr);
+
+ private:
+  TCPSocket(int sock);
+
+  int sock_;
+};
+
+} // namespace mlx::core::distributed::detail