1/* SPDX-License-Identifier: MIT */
2/*
3 * Details of the "wire" protocol between Xen Store Daemon and client
4 * library or guest kernel.
5 * Copyright (C) 2005 Rusty Russell IBM Corporation
6 */
7
8#ifndef _XS_WIRE_H
9#define _XS_WIRE_H
10
11enum xsd_sockmsg_type
12{
13    XS_CONTROL,
14#define XS_DEBUG XS_CONTROL
15    XS_DIRECTORY,
16    XS_READ,
17    XS_GET_PERMS,
18    XS_WATCH,
19    XS_UNWATCH,
20    XS_TRANSACTION_START,
21    XS_TRANSACTION_END,
22    XS_INTRODUCE,
23    XS_RELEASE,
24    XS_GET_DOMAIN_PATH,
25    XS_WRITE,
26    XS_MKDIR,
27    XS_RM,
28    XS_SET_PERMS,
29    XS_WATCH_EVENT,
30    XS_ERROR,
31    XS_IS_DOMAIN_INTRODUCED,
32    XS_RESUME,
33    XS_SET_TARGET,
34    /* XS_RESTRICT has been removed */
35    XS_RESET_WATCHES = XS_SET_TARGET + 2,
36    XS_DIRECTORY_PART,
37
38    XS_TYPE_COUNT,      /* Number of valid types. */
39
40    XS_INVALID = 0xffff /* Guaranteed to remain an invalid type */
41};
42
43#define XS_WRITE_NONE "NONE"
44#define XS_WRITE_CREATE "CREATE"
45#define XS_WRITE_CREATE_EXCL "CREATE|EXCL"
46
47/* We hand errors as strings, for portability. */
48struct xsd_errors
49{
50    int errnum;
51    const char *errstring;
52};
53#define XSD_ERROR(x) { x, #x }
54static struct xsd_errors xsd_errors[] __attribute__((unused)) = {
55    XSD_ERROR(EINVAL),
56    XSD_ERROR(EACCES),
57    XSD_ERROR(EEXIST),
58    XSD_ERROR(EISDIR),
59    XSD_ERROR(ENOENT),
60    XSD_ERROR(ENOMEM),
61    XSD_ERROR(ENOSPC),
62    XSD_ERROR(EIO),
63    XSD_ERROR(ENOTEMPTY),
64    XSD_ERROR(ENOSYS),
65    XSD_ERROR(EROFS),
66    XSD_ERROR(EBUSY),
67    XSD_ERROR(EAGAIN),
68    XSD_ERROR(EISCONN),
69    XSD_ERROR(E2BIG)
70};
71
72struct xsd_sockmsg
73{
74    uint32_t type;  /* XS_??? */
75    uint32_t req_id;/* Request identifier, echoed in daemon's response.  */
76    uint32_t tx_id; /* Transaction id (0 if not related to a transaction). */
77    uint32_t len;   /* Length of data following this. */
78
79    /* Generally followed by nul-terminated string(s). */
80};
81
82enum xs_watch_type
83{
84    XS_WATCH_PATH = 0,
85    XS_WATCH_TOKEN
86};
87
88/* Inter-domain shared memory communications. */
89#define XENSTORE_RING_SIZE 1024
90typedef uint32_t XENSTORE_RING_IDX;
91#define MASK_XENSTORE_IDX(idx) ((idx) & (XENSTORE_RING_SIZE-1))
92struct xenstore_domain_interface {
93    char req[XENSTORE_RING_SIZE]; /* Requests to xenstore daemon. */
94    char rsp[XENSTORE_RING_SIZE]; /* Replies and async watch events. */
95    XENSTORE_RING_IDX req_cons, req_prod;
96    XENSTORE_RING_IDX rsp_cons, rsp_prod;
97    uint32_t server_features; /* Bitmap of features supported by the server */
98    uint32_t connection;
99    uint32_t error;
100};
101
102/* Violating this is very bad.  See docs/misc/xenstore.txt. */
103#define XENSTORE_PAYLOAD_MAX 4096
104
105/* Violating these just gets you an error back */
106#define XENSTORE_ABS_PATH_MAX 3072
107#define XENSTORE_REL_PATH_MAX 2048
108
109/* The ability to reconnect a ring */
110#define XENSTORE_SERVER_FEATURE_RECONNECTION 1
111/* The presence of the "error" field in the ring page */
112#define XENSTORE_SERVER_FEATURE_ERROR        2
113
114/* Valid values for the connection field */
115#define XENSTORE_CONNECTED 0 /* the steady-state */
116#define XENSTORE_RECONNECT 1 /* guest has initiated a reconnect */
117
118/* Valid values for the error field */
119#define XENSTORE_ERROR_NONE    0 /* No error */
120#define XENSTORE_ERROR_COMM    1 /* Communication problem */
121#define XENSTORE_ERROR_RINGIDX 2 /* Invalid ring index */
122#define XENSTORE_ERROR_PROTO   3 /* Protocol violation (payload too long) */
123
124#endif /* _XS_WIRE_H */
125