Sockets: Add SetNagleBuffering()

src/util/sockets.cpp

@@ -33,6 +33,7 @@ using nfds_t = ULONG;
 #include <arpa/inet.h>
 #include <errno.h>
 #include <netinet/in.h>
+#include <netinet/tcp.h>
 #include <poll.h>
 #include <sys/ioctl.h>
 #include <sys/socket.h>
@@ -76,6 +77,12 @@ void SocketAddress::SetFromSockaddr(const void* sa, size_t length)
     std::memset(m_data + m_length, 0, sizeof(m_data) - m_length);
 }
 
+bool SocketAddress::IsIPAddress() const
+{
+  const sockaddr* addr = reinterpret_cast<const sockaddr*>(m_data);
+  return (addr->sa_family == AF_INET || addr->sa_family == AF_INET6);
+}
+
 std::optional<SocketAddress> SocketAddress::Parse(Type type, const char* address, u32 port, Error* error)
 {
   std::optional<SocketAddress> ret = SocketAddress();
@@ -695,6 +702,24 @@ size_t StreamSocket::WriteVector(const void** buffers, const size_t* buffer_leng
 #endif
 }
 
+bool StreamSocket::SetNagleBuffering(bool enabled, Error* error /* = nullptr */)
+{
+  if (!m_local_address.IsIPAddress())
+  {
+    Error::SetStringView(error, "Attempting to disable nagle on a non-IP socket.");
+    return false;
+  }
+
+  int disable = enabled ? 0 : 1;
+  if (setsockopt(m_descriptor, IPPROTO_TCP, TCP_NODELAY, reinterpret_cast<char*>(&disable), sizeof(disable)) != 0)
+  {
+    Error::SetSocket(error, "setsockopt(TCP_NODELAY) failed: ", WSAGetLastError());
+    return false;
+  }
+
+  return true;
+}
+
 void StreamSocket::Close()
 {
   std::unique_lock lock(m_lock);

src/util/sockets.h

@@ -56,6 +56,9 @@ struct SocketAddress final
   // initializers
   void SetFromSockaddr(const void* sa, size_t length);
 
+  /// Returns true if the address is IP.
+  bool IsIPAddress() const;
+
 private:
   u8 m_data[128] = {};
   u32 m_length = 0;
@@ -218,6 +221,9 @@ class StreamSocket : public BaseSocket
   size_t Write(const void* buffer, size_t buffer_size);
   size_t WriteVector(const void** buffers, const size_t* buffer_lengths, size_t num_buffers);
 
+  /// Disables Nagle's buffering algorithm, i.e. TCP_NODELAY.
+  bool SetNagleBuffering(bool enabled, Error* error = nullptr);
+
 protected:
   virtual void OnConnected() = 0;
   virtual void OnDisconnected(const Error& error) = 0;