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 void (*cancel_requests)(RngBackend *s); 41 42 void (*opened)(RngBackend *s, Error **errp); 43 }; 44 45 struct RngBackend 46 { 47 Object parent; 48 49 /*< protected >*/ 50 bool opened; 51 }; 52 53 /** 54 * rng_backend_request_entropy: 55 * @s: the backend to request entropy from 56 * @size: the number of bytes of data to request 57 * @receive_entropy: a function to be invoked when entropy is available 58 * @opaque: data that should be passed to @receive_entropy 59 * 60 * This function is used by the front-end to request entropy from an entropy 61 * source. This function can be called multiple times before @receive_entropy 62 * is invoked with different values of @receive_entropy and @opaque. The 63 * backend will queue each request and handle appropriately. 64 * 65 * The backend does not need to pass the full amount of data to @receive_entropy 66 * but will pass a value greater than 0. 67 */ 68 void rng_backend_request_entropy(RngBackend *s, size_t size, 69 EntropyReceiveFunc *receive_entropy, 70 void *opaque); 71 72 /** 73 * rng_backend_cancel_requests: 74 * @s: the backend to cancel all pending requests in 75 * 76 * Cancels all pending requests submitted by @rng_backend_request_entropy. This 77 * should be used by a device during reset or in preparation for live migration 78 * to stop tracking any request. 79 */ 80 void rng_backend_cancel_requests(RngBackend *s); 81 #endif 82