net/SocketDescriptor: add GetType(), IsStream()

src/net/SocketDescriptor.cxx

@@ -44,6 +44,25 @@
 #include <errno.h>
 #include <string.h>
 
+int
+SocketDescriptor::GetType() const noexcept
+{
+	assert(IsDefined());
+
+	int type;
+	socklen_t size = sizeof(type);
+	return getsockopt(fd, SOL_SOCKET, SO_TYPE,
+			  (char *)&type, &size) == 0
+		? type
+		: -1;
+}
+
+bool
+SocketDescriptor::IsStream() const noexcept
+{
+	return GetType() == SOCK_STREAM;
+}
+
 #ifdef _WIN32
 
 void

src/net/SocketDescriptor.hxx

@@ -82,6 +82,20 @@ public:
 	using FileDescriptor::IsValid;
 	using FileDescriptor::IsSocket;
 #endif
+
+	/**
+	 * Determine the socket type, i.e. SOCK_STREAM, SOCK_DGRAM or
+	 * SOCK_SEQPACKET.  Returns -1 on error.
+	 */
+	gcc_pure
+	int GetType() const noexcept;
+
+	/**
+	 * Is this a stream socket?
+	 */
+	gcc_pure
+	bool IsStream() const noexcept;
+
 	using FileDescriptor::Get;
 	using FileDescriptor::Set;
 	using FileDescriptor::Steal;