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
  18 #define TYPE_RNG_BACKEND "rng-backend"
  19 #define RNG_BACKEND(obj) \
  20     OBJECT_CHECK(RngBackend, (obj), TYPE_RNG_BACKEND)
  21 #define RNG_BACKEND_GET_CLASS(obj) \
  22     OBJECT_GET_CLASS(RngBackendClass, (obj), TYPE_RNG_BACKEND)
  23 #define RNG_BACKEND_CLASS(klass) \
  24     OBJECT_CLASS_CHECK(RngBackendClass, (klass), TYPE_RNG_BACKEND)
  25
  26 typedef struct RngRequest RngRequest;
  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 RngRequest
  35 {
  36     EntropyReceiveFunc *receive_entropy;
  37     uint8_t *data;
  38     void *opaque;
  39     size_t offset;
  40     size_t size;
  41     QSIMPLEQ_ENTRY(RngRequest) next;
  42 };
  43
  44 struct RngBackendClass
  45 {
  46     ObjectClass parent_class;
  47
  48     void (*request_entropy)(RngBackend *s, RngRequest *req);
  49
  50     void (*opened)(RngBackend *s, Error **errp);
  51 };
  52
  53 struct RngBackend
  54 {
  55     Object parent;
  56
  57     /*< protected >*/
  58     bool opened;
  59     QSIMPLEQ_HEAD(, RngRequest) requests;
  60 };
  61
  62
  63 /**
  64  * rng_backend_request_entropy:
  65  * @s: the backend to request entropy from
  66  * @size: the number of bytes of data to request
  67  * @receive_entropy: a function to be invoked when entropy is available
  68  * @opaque: data that should be passed to @receive_entropy
  69  *
  70  * This function is used by the front-end to request entropy from an entropy
  71  * source.  This function can be called multiple times before @receive_entropy
  72  * is invoked with different values of @receive_entropy and @opaque.  The
  73  * backend will queue each request and handle appropriately.
  74  *
  75  * The backend does not need to pass the full amount of data to @receive_entropy
  76  * but will pass a value greater than 0.
  77  */
  78 void rng_backend_request_entropy(RngBackend *s, size_t size,
  79                                  EntropyReceiveFunc *receive_entropy,
  80                                  void *opaque);
  81
  82 /**
  83  * rng_backend_free_request:
  84  * @s: the backend that created the request
  85  * @req: the request to finalize
  86  *
  87  * Used by child rng backend classes to finalize requests once they've been
  88  * processed. The request is removed from the list of active requests and
  89  * deleted.
  90  */
  91 void rng_backend_finalize_request(RngBackend *s, RngRequest *req);
  92 #endif