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