From fc00c656c96528112d05cf0edf8631bd5eaea446 Mon Sep 17 00:00:00 2001
From: Kacper <kacper@mail.openlinux.dev>
Date: Sun, 7 Dec 2025 20:10:31 +0100
Subject: Add build system scaffolding and libc headers

---
 include/arch/x86_64/linux/nbd.h | 112 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 112 insertions(+)
 create mode 100644 include/arch/x86_64/linux/nbd.h

(limited to 'include/arch/x86_64/linux/nbd.h')

diff --git a/include/arch/x86_64/linux/nbd.h b/include/arch/x86_64/linux/nbd.h
new file mode 100644
index 00000000..c339b184
--- /dev/null
+++ b/include/arch/x86_64/linux/nbd.h
@@ -0,0 +1,112 @@
+/* SPDX-License-Identifier: GPL-1.0+ WITH Linux-syscall-note */
+/*
+ * 1999 Copyright (C) Pavel Machek, pavel@ucw.cz. This code is GPL.
+ * 1999/11/04 Copyright (C) 1999 VMware, Inc. (Regis "HPReg" Duchesne)
+ *            Made nbd_end_request() use the io_request_lock
+ * 2001 Copyright (C) Steven Whitehouse
+ *            New nbd_end_request() for compatibility with new linux block
+ *            layer code.
+ * 2003/06/24 Louis D. Langholtz <ldl@aros.net>
+ *            Removed unneeded blksize_bits field from nbd_device struct.
+ *            Cleanup PARANOIA usage & code.
+ * 2004/02/19 Paul Clements
+ *            Removed PARANOIA, plus various cleanup and comments
+ * 2023 Copyright Red Hat
+ *            Link to userspace extensions, favor cookie over handle.
+ */
+
+#ifndef LINUX_NBD_H
+#define LINUX_NBD_H
+
+#include <linux/types.h>
+
+#define NBD_SET_SOCK	    _IO(0xab, 0)
+#define NBD_SET_BLKSIZE	    _IO(0xab, 1)
+#define NBD_SET_SIZE	    _IO(0xab, 2)
+#define NBD_DO_IT	    _IO(0xab, 3)
+#define NBD_CLEAR_SOCK	    _IO(0xab, 4)
+#define NBD_CLEAR_QUE	    _IO(0xab, 5)
+#define NBD_PRINT_DEBUG	    _IO(0xab, 6)
+#define NBD_SET_SIZE_BLOCKS _IO(0xab, 7)
+#define NBD_DISCONNECT	    _IO(0xab, 8)
+#define NBD_SET_TIMEOUT	    _IO(0xab, 9)
+#define NBD_SET_FLAGS	    _IO(0xab, 10)
+
+/*
+ * See also https://github.com/NetworkBlockDevice/nbd/blob/master/doc/proto.md
+ * for additional userspace extensions not yet utilized in the kernel module.
+ */
+
+enum {
+	NBD_CMD_READ = 0,
+	NBD_CMD_WRITE = 1,
+	NBD_CMD_DISC = 2,
+	NBD_CMD_FLUSH = 3,
+	NBD_CMD_TRIM = 4,
+	/* userspace defines additional extension commands */
+	NBD_CMD_WRITE_ZEROES = 6,
+};
+
+/* values for flags field, these are server interaction specific. */
+#define NBD_FLAG_HAS_FLAGS	   (1 << 0) /* nbd-server supports flags */
+#define NBD_FLAG_READ_ONLY	   (1 << 1) /* device is read-only */
+#define NBD_FLAG_SEND_FLUSH	   (1 << 2) /* can flush writeback cache */
+#define NBD_FLAG_SEND_FUA	   (1 << 3) /* send FUA (forced unit access) */
+#define NBD_FLAG_ROTATIONAL	   (1 << 4) /* device is rotational */
+#define NBD_FLAG_SEND_TRIM	   (1 << 5) /* send trim/discard */
+#define NBD_FLAG_SEND_WRITE_ZEROES (1 << 6) /* supports WRITE_ZEROES */
+/* there is a gap here to match userspace */
+#define NBD_FLAG_CAN_MULTI_CONN \
+	(1 << 8) /* Server supports multiple connections per export. */
+
+/* values for cmd flags in the upper 16 bits of request type */
+#define NBD_CMD_FLAG_FUA (1 << 16) /* FUA (forced unit access) op */
+#define NBD_CMD_FLAG_NO_HOLE \
+	(1 << 17) /* Do not punch a hole for WRITE_ZEROES */
+
+/* These are client behavior specific flags. */
+#define NBD_CFLAG_DESTROY_ON_DISCONNECT      \
+	(1 << 0) /* delete the nbd device on \
+		    disconnect. */
+#define NBD_CFLAG_DISCONNECT_ON_CLOSE            \
+	(1 << 1) /* disconnect the nbd device on \
+		  *  close by last opener.       \
+		  */
+
+/* userspace doesn't need the nbd_device structure */
+
+/* These are sent over the network in the request/reply magic fields */
+
+#define NBD_REQUEST_MAGIC 0x25609513
+#define NBD_REPLY_MAGIC	  0x67446698
+/* Do *not* use magics: 0x12560953 0x96744668. */
+/* magic 0x668e33ef for structured reply not supported by kernel yet */
+
+/*
+ * This is the packet used for communication between client and
+ * server. All data are in network byte order.
+ */
+struct nbd_request {
+	__be32 magic; /* NBD_REQUEST_MAGIC	*/
+	__be32 type;  /* See NBD_CMD_*	*/
+	union {
+		__be64 cookie;	/* Opaque identifier for request	*/
+		char handle[8]; /* older spelling of cookie		*/
+	};
+	__be64 from;
+	__be32 len;
+} __attribute__((packed));
+
+/*
+ * This is the reply packet that nbd-server sends back to the client after
+ * it has completed an I/O request (or an error occurs).
+ */
+struct nbd_reply {
+	__be32 magic; /* NBD_REPLY_MAGIC	*/
+	__be32 error; /* 0 = ok, else error	*/
+	union {
+		__be64 cookie;	/* Opaque identifier from request	*/
+		char handle[8]; /* older spelling of cookie		*/
+	};
+};
+#endif /* LINUX_NBD_H */
-- 
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