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 "qemu/queue.h"
  17#include "qom/object.h"
  18
  19#define TYPE_RNG_BACKEND "rng-backend"
  20OBJECT_DECLARE_TYPE(RngBackend, RngBackendClass,
  21                    RNG_BACKEND)
  22
  23#define TYPE_RNG_BUILTIN "rng-builtin"
  24
  25typedef struct RngRequest RngRequest;
  26
  27typedef void (EntropyReceiveFunc)(void *opaque,
  28                                  const void *data,
  29                                  size_t size);
  30
  31struct RngRequest
  32{
  33    EntropyReceiveFunc *receive_entropy;
  34    uint8_t *data;
  35    void *opaque;
  36    size_t offset;
  37    size_t size;
  38    QSIMPLEQ_ENTRY(RngRequest) next;
  39};
  40
  41struct RngBackendClass
  42{
  43    ObjectClass parent_class;
  44
  45    void (*request_entropy)(RngBackend *s, RngRequest *req);
  46
  47    void (*opened)(RngBackend *s, Error **errp);
  48};
  49
  50struct RngBackend
  51{
  52    Object parent;
  53
  54    /*< protected >*/
  55    bool opened;
  56    QSIMPLEQ_HEAD(, RngRequest) requests;
  57};
  58
  59
  60/**
  61 * rng_backend_request_entropy:
  62 * @s: the backend to request entropy from
  63 * @size: the number of bytes of data to request
  64 * @receive_entropy: a function to be invoked when entropy is available
  65 * @opaque: data that should be passed to @receive_entropy
  66 *
  67 * This function is used by the front-end to request entropy from an entropy
  68 * source.  This function can be called multiple times before @receive_entropy
  69 * is invoked with different values of @receive_entropy and @opaque.  The
  70 * backend will queue each request and handle appropriately.
  71 *
  72 * The backend does not need to pass the full amount of data to @receive_entropy
  73 * but will pass a value greater than 0.
  74 */
  75void rng_backend_request_entropy(RngBackend *s, size_t size,
  76                                 EntropyReceiveFunc *receive_entropy,
  77                                 void *opaque);
  78
  79/**
  80 * rng_backend_free_request:
  81 * @s: the backend that created the request
  82 * @req: the request to finalize
  83 *
  84 * Used by child rng backend classes to finalize requests once they've been
  85 * processed. The request is removed from the list of active requests and
  86 * deleted.
  87 */
  88void rng_backend_finalize_request(RngBackend *s, RngRequest *req);
  89#endif
  90