1 /* SPDX-License-Identifier: MIT
2  *
3  * Details of the "wire" protocol between Xen Store Daemon and client
4  * library or guest kernel.
5  *
6  * Copyright (C) 2005 Rusty Russell IBM Corporation
7  */
8 
9 #ifndef _XS_WIRE_H
10 #define _XS_WIRE_H
11 
12 enum xsd_sockmsg_type {
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 	int errnum;
50 	const char *errstring;
51 };
52 
53 #ifdef EINVAL
54 #define XSD_ERROR(x) { x, #x }
55 /* LINTED: static unused */
56 static struct xsd_errors xsd_errors[]
57 #if defined(__GNUC__)
58 __attribute__((unused))
59 #endif
60 	= {
61 	XSD_ERROR(EINVAL),
62 	XSD_ERROR(EACCES),
63 	XSD_ERROR(EEXIST),
64 	XSD_ERROR(EISDIR),
65 	XSD_ERROR(ENOENT),
66 	XSD_ERROR(ENOMEM),
67 	XSD_ERROR(ENOSPC),
68 	XSD_ERROR(EIO),
69 	XSD_ERROR(ENOTEMPTY),
70 	XSD_ERROR(ENOSYS),
71 	XSD_ERROR(EROFS),
72 	XSD_ERROR(EBUSY),
73 	XSD_ERROR(EAGAIN),
74 	XSD_ERROR(EISCONN),
75 	XSD_ERROR(E2BIG)
76 };
77 #endif
78 
79 struct xsd_sockmsg {
80 	u32 type;  /* XS_??? */
81 	u32 req_id;/* Request identifier, echoed in daemon's response.  */
82 	u32 tx_id; /* Transaction id (0 if not related to a transaction). */
83 	u32 len;   /* Length of data following this. */
84 
85 	/* Generally followed by nul-terminated string(s). */
86 };
87 
88 enum xs_watch_type {
89 	XS_WATCH_PATH = 0,
90 	XS_WATCH_TOKEN
91 };
92 
93 /*
94  * `incontents 150 xenstore_struct XenStore wire protocol.
95  *
96  * Inter-domain shared memory communications.
97  */
98 #define XENSTORE_RING_SIZE 1024
99 typedef u32 XENSTORE_RING_IDX;
100 #define MASK_XENSTORE_IDX(idx) ((idx) & (XENSTORE_RING_SIZE - 1))
101 struct xenstore_domain_interface {
102 	char req[XENSTORE_RING_SIZE]; /* Requests to xenstore daemon. */
103 	char rsp[XENSTORE_RING_SIZE]; /* Replies and async watch events. */
104 	XENSTORE_RING_IDX req_cons, req_prod;
105 	XENSTORE_RING_IDX rsp_cons, rsp_prod;
106 	u32 server_features; /* Bitmap of features supported by the server */
107 	u32 connection;
108 };
109 
110 /* Violating this is very bad.  See docs/misc/xenstore.txt. */
111 #define XENSTORE_PAYLOAD_MAX 4096
112 
113 /* Violating these just gets you an error back */
114 #define XENSTORE_ABS_PATH_MAX 3072
115 #define XENSTORE_REL_PATH_MAX 2048
116 
117 /* The ability to reconnect a ring */
118 #define XENSTORE_SERVER_FEATURE_RECONNECTION 1
119 
120 /* Valid values for the connection field */
121 #define XENSTORE_CONNECTED 0 /* the steady-state */
122 #define XENSTORE_RECONNECT 1 /* guest has initiated a reconnect */
123 
124 #endif /* _XS_WIRE_H */
125 
126 /*
127  * Local variables:
128  * mode: C
129  * c-file-style: "BSD"
130  * c-basic-offset: 4
131  * tab-width: 8
132  * indent-tabs-mode: nil
133  * End:
134  */
135