include/xen/interface/io/xs_wire.h

/* SPDX-License-Identifier: MIT
 *
 * Details of the "wire" protocol between Xen Store Daemon and client
 * library or guest kernel.
 *
 * Copyright (C) 2005 Rusty Russell IBM Corporation
 */

#ifndef _XS_WIRE_H
#define _XS_WIRE_H

enum xsd_sockmsg_type {
	XS_CONTROL,
#define XS_DEBUG XS_CONTROL
	XS_DIRECTORY,
	XS_READ,
	XS_GET_PERMS,
	XS_WATCH,
	XS_UNWATCH,
	XS_TRANSACTION_START,
	XS_TRANSACTION_END,
	XS_INTRODUCE,
	XS_RELEASE,
	XS_GET_DOMAIN_PATH,
	XS_WRITE,
	XS_MKDIR,
	XS_RM,
	XS_SET_PERMS,
	XS_WATCH_EVENT,
	XS_ERROR,
	XS_IS_DOMAIN_INTRODUCED,
	XS_RESUME,
	XS_SET_TARGET,
	/* XS_RESTRICT has been removed */
	XS_RESET_WATCHES = XS_SET_TARGET + 2,
	XS_DIRECTORY_PART,

	XS_TYPE_COUNT,      /* Number of valid types. */

	XS_INVALID = 0xffff /* Guaranteed to remain an invalid type */
};

#define XS_WRITE_NONE "NONE"
#define XS_WRITE_CREATE "CREATE"
#define XS_WRITE_CREATE_EXCL "CREATE|EXCL"

/* We hand errors as strings, for portability. */
struct xsd_errors {
	int errnum;
	const char *errstring;
};

#ifdef EINVAL
#define XSD_ERROR(x) { x, #x }
/* LINTED: static unused */
static struct xsd_errors xsd_errors[]
#if defined(__GNUC__)
__attribute__((unused))
#endif
	= {
	XSD_ERROR(EINVAL),
	XSD_ERROR(EACCES),
	XSD_ERROR(EEXIST),
	XSD_ERROR(EISDIR),
	XSD_ERROR(ENOENT),
	XSD_ERROR(ENOMEM),
	XSD_ERROR(ENOSPC),
	XSD_ERROR(EIO),
	XSD_ERROR(ENOTEMPTY),
	XSD_ERROR(ENOSYS),
	XSD_ERROR(EROFS),
	XSD_ERROR(EBUSY),
	XSD_ERROR(EAGAIN),
	XSD_ERROR(EISCONN),
	XSD_ERROR(E2BIG)
};
#endif

struct xsd_sockmsg {
	u32 type;  /* XS_??? */
	u32 req_id;/* Request identifier, echoed in daemon's response.  */
	u32 tx_id; /* Transaction id (0 if not related to a transaction). */
	u32 len;   /* Length of data following this. */

	/* Generally followed by nul-terminated string(s). */
};

enum xs_watch_type {
	XS_WATCH_PATH = 0,
	XS_WATCH_TOKEN
};

/*
 * `incontents 150 xenstore_struct XenStore wire protocol.
 *
 * Inter-domain shared memory communications.
 */
#define XENSTORE_RING_SIZE 1024
typedef u32 XENSTORE_RING_IDX;
#define MASK_XENSTORE_IDX(idx) ((idx) & (XENSTORE_RING_SIZE - 1))
struct xenstore_domain_interface {
	char req[XENSTORE_RING_SIZE]; /* Requests to xenstore daemon. */
	char rsp[XENSTORE_RING_SIZE]; /* Replies and async watch events. */
	XENSTORE_RING_IDX req_cons, req_prod;
	XENSTORE_RING_IDX rsp_cons, rsp_prod;
	u32 server_features; /* Bitmap of features supported by the server */
	u32 connection;
};

/* Violating this is very bad.  See docs/misc/xenstore.txt. */
#define XENSTORE_PAYLOAD_MAX 4096

/* Violating these just gets you an error back */
#define XENSTORE_ABS_PATH_MAX 3072
#define XENSTORE_REL_PATH_MAX 2048

/* The ability to reconnect a ring */
#define XENSTORE_SERVER_FEATURE_RECONNECTION 1

/* Valid values for the connection field */
#define XENSTORE_CONNECTED 0 /* the steady-state */
#define XENSTORE_RECONNECT 1 /* guest has initiated a reconnect */

#endif /* _XS_WIRE_H */

/*
 * Local variables:
 * mode: C
 * c-file-style: "BSD"
 * c-basic-offset: 4
 * tab-width: 8
 * indent-tabs-mode: nil
 * End:
 */