drivers/hv/hv_kvp.h

   1 /*
   2  * An implementation of HyperV key value pair (KVP) functionality for Linux.
   3  *
   4  *
   5  * Copyright (C) 2010, Novell, Inc.
   6  * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License version 2 as published
  10  * by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  15  * NON INFRINGEMENT.  See the GNU General Public License for more
  16  * details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  21  *
  22  */
  23 #ifndef _KVP_H
  24 #define _KVP_H_
  25
  26 /*
  27  * Maximum value size - used for both key names and value data, and includes
  28  * any applicable NULL terminators.
  29  *
  30  * Note:  This limit is somewhat arbitrary, but falls easily within what is
  31  * supported for all native guests (back to Win 2000) and what is reasonable
  32  * for the IC KVP exchange functionality.  Note that Windows Me/98/95 are
  33  * limited to 255 character key names.
  34  *
  35  * MSDN recommends not storing data values larger than 2048 bytes in the
  36  * registry.
  37  *
  38  * Note:  This value is used in defining the KVP exchange message - this value
  39  * cannot be modified without affecting the message size and compatibility.
  40  */
  41
  42 /*
  43  * bytes, including any null terminators
  44  */
  45 #define HV_KVP_EXCHANGE_MAX_VALUE_SIZE          (2048)
  46
  47
  48 /*
  49  * Maximum key size - the registry limit for the length of an entry name
  50  * is 256 characters, including the null terminator
  51  */
  52
  53 #define HV_KVP_EXCHANGE_MAX_KEY_SIZE            (512)
  54
  55 /*
  56  * In Linux, we implement the KVP functionality in two components:
  57  * 1) The kernel component which is packaged as part of the hv_utils driver
  58  * is responsible for communicating with the host and responsible for
  59  * implementing the host/guest protocol. 2) A user level daemon that is
  60  * responsible for data gathering.
  61  *
  62  * Host/Guest Protocol: The host iterates over an index and expects the guest
  63  * to assign a key name to the index and also return the value corresponding to
  64  * the key. The host will have atmost one KVP transaction outstanding at any
  65  * given point in time. The host side iteration stops when the guest returns
  66  * an error. Microsoft has specified the following mapping of key names to
  67  * host specified index:
  68  *
  69  *      Index           Key Name
  70  *      0               FullyQualifiedDomainName
  71  *      1               IntegrationServicesVersion
  72  *      2               NetworkAddressIPv4
  73  *      3               NetworkAddressIPv6
  74  *      4               OSBuildNumber
  75  *      5               OSName
  76  *      6               OSMajorVersion
  77  *      7               OSMinorVersion
  78  *      8               OSVersion
  79  *      9               ProcessorArchitecture
  80  *
  81  * The Windows host expects the Key Name and Key Value to be encoded in utf16.
  82  *
  83  * Guest Kernel/KVP Daemon Protocol: As noted earlier, we implement all of the
  84  * data gathering functionality in a user mode daemon. The user level daemon
  85  * is also responsible for binding the key name to the index as well. The
  86  * kernel and user-level daemon communicate using a connector channel.
  87  *
  88  * The user mode component first registers with the
  89  * the kernel component. Subsequently, the kernel component requests, data
  90  * for the specified keys. In response to this message the user mode component
  91  * fills in the value corresponding to the specified key. We overload the
  92  * sequence field in the cn_msg header to define our KVP message types.
  93  *
  94  *
  95  * The kernel component simply acts as a conduit for communication between the
  96  * Windows host and the user-level daemon. The kernel component passes up the
  97  * index received from the Host to the user-level daemon. If the index is
  98  * valid (supported), the corresponding key as well as its
  99  * value (both are strings) is returned. If the index is invalid
 100  * (not supported), a NULL key string is returned.
 101  */
 102
 103 /*
 104  *
 105  * The following definitions are shared with the user-mode component; do not
 106  * change any of this without making the corresponding changes in
 107  * the KVP user-mode component.
 108  */
 109
 110 #define CN_KVP_VAL             0x1 /* This supports queries from the kernel */
 111 #define CN_KVP_USER_VAL       0x2 /* This supports queries from the user */
 112
 113 enum hv_ku_op {
 114         KVP_REGISTER = 0, /* Register the user mode component */
 115         KVP_KERNEL_GET, /* Kernel is requesting the value */
 116         KVP_KERNEL_SET, /* Kernel is providing the value */
 117         KVP_USER_GET,  /* User is requesting the value */
 118         KVP_USER_SET  /* User is providing the value */
 119 };
 120
 121 struct hv_ku_msg {
 122         __u32 kvp_index; /* Key index */
 123         __u8  kvp_key[HV_KVP_EXCHANGE_MAX_KEY_SIZE]; /* Key name */
 124         __u8  kvp_value[HV_KVP_EXCHANGE_MAX_VALUE_SIZE]; /* Key  value */
 125 };
 126
 127
 128
 129
 130 #ifdef __KERNEL__
 131
 132 /*
 133  * Registry value types.
 134  */
 135
 136 #define REG_SZ 1
 137
 138 enum hv_kvp_exchg_op {
 139         KVP_OP_GET = 0,
 140         KVP_OP_SET,
 141         KVP_OP_DELETE,
 142         KVP_OP_ENUMERATE,
 143         KVP_OP_COUNT /* Number of operations, must be last. */
 144 };
 145
 146 enum hv_kvp_exchg_pool {
 147         KVP_POOL_EXTERNAL = 0,
 148         KVP_POOL_GUEST,
 149         KVP_POOL_AUTO,
 150         KVP_POOL_AUTO_EXTERNAL,
 151         KVP_POOL_AUTO_INTERNAL,
 152         KVP_POOL_COUNT /* Number of pools, must be last. */
 153 };
 154
 155 struct hv_kvp_hdr {
 156         u8 operation;
 157         u8 pool;
 158 };
 159
 160 struct hv_kvp_exchg_msg_value {
 161         u32 value_type;
 162         u32 key_size;
 163         u32 value_size;
 164         u8 key[HV_KVP_EXCHANGE_MAX_KEY_SIZE];
 165         u8 value[HV_KVP_EXCHANGE_MAX_VALUE_SIZE];
 166 };
 167
 168 struct hv_kvp_msg_enumerate {
 169         u32 index;
 170         struct hv_kvp_exchg_msg_value data;
 171 };
 172
 173 struct hv_kvp_msg {
 174         struct hv_kvp_hdr       kvp_hdr;
 175         struct hv_kvp_msg_enumerate     kvp_data;
 176 };
 177
 178 int hv_kvp_init(struct hv_util_service *);
 179 void hv_kvp_deinit(void);
 180 void hv_kvp_onchannelcallback(void *);
 181
 182 #endif /* __KERNEL__ */
 183 #endif  /* _KVP_H */
 184