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
11 enum 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. */
48 struct xsd_errors
49 {
50 int errnum;
51 const char *errstring;
52 };
53 #define XSD_ERROR(x) { x, #x }
54 static 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
72 struct 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
82 enum 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
90 typedef uint32_t XENSTORE_RING_IDX;
91 #define MASK_XENSTORE_IDX(idx) ((idx) & (XENSTORE_RING_SIZE-1))
92 struct 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
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