include/sysemu/rng.h

   1 /*
   2  * QEMU Random Number Generator Backend
   3  *
   4  * Copyright IBM, Corp. 2012
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  */
  12
  13 #ifndef QEMU_RNG_H
  14 #define QEMU_RNG_H
  15
  16 #include "qom/object.h"
  17 #include "qemu-common.h"
  18
  19 #define TYPE_RNG_BACKEND "rng-backend"
  20 #define RNG_BACKEND(obj) \
  21     OBJECT_CHECK(RngBackend, (obj), TYPE_RNG_BACKEND)
  22 #define RNG_BACKEND_GET_CLASS(obj) \
  23     OBJECT_GET_CLASS(RngBackendClass, (obj), TYPE_RNG_BACKEND)
  24 #define RNG_BACKEND_CLASS(klass) \
  25     OBJECT_CLASS_CHECK(RngBackendClass, (klass), TYPE_RNG_BACKEND)
  26
  27 typedef struct RngBackendClass RngBackendClass;
  28 typedef struct RngBackend RngBackend;
  29
  30 typedef void (EntropyReceiveFunc)(void *opaque,
  31                                   const void *data,
  32                                   size_t size);
  33
  34 struct RngBackendClass
  35 {
  36     ObjectClass parent_class;
  37
  38     void (*request_entropy)(RngBackend *s, size_t size,
  39                             EntropyReceiveFunc *receive_entropy, void *opaque);
  40
  41     void (*opened)(RngBackend *s, Error **errp);
  42 };
  43
  44 struct RngBackend
  45 {
  46     Object parent;
  47
  48     /*< protected >*/
  49     bool opened;
  50 };
  51
  52 /**
  53  * rng_backend_request_entropy:
  54  * @s: the backend to request entropy from
  55  * @size: the number of bytes of data to request
  56  * @receive_entropy: a function to be invoked when entropy is available
  57  * @opaque: data that should be passed to @receive_entropy
  58  *
  59  * This function is used by the front-end to request entropy from an entropy
  60  * source.  This function can be called multiple times before @receive_entropy
  61  * is invoked with different values of @receive_entropy and @opaque.  The
  62  * backend will queue each request and handle appropriately.
  63  *
  64  * The backend does not need to pass the full amount of data to @receive_entropy
  65  * but will pass a value greater than 0.
  66  */
  67 void rng_backend_request_entropy(RngBackend *s, size_t size,
  68                                  EntropyReceiveFunc *receive_entropy,
  69                                  void *opaque);
  70 #endif