LXR qemu/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
  26typedef struct RngRequest RngRequest;
  27typedef struct RngBackendClass RngBackendClass;
  28typedef struct RngBackend RngBackend;
  29
  30typedef void (EntropyReceiveFunc)(void *opaque,
  31                                  const void *data,
  32                                  size_t size);
  33
  34struct 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
  44struct 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
  53struct 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 */
  78void 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 */
  91void rng_backend_finalize_request(RngBackend *s, RngRequest *req);
  92#endif
  93