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" 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 RngRequest RngRequest; 28 typedef struct RngBackendClass RngBackendClass; 29 typedef struct RngBackend RngBackend; 30 31 typedef void (EntropyReceiveFunc)(void *opaque, 32 const void *data, 33 size_t size); 34 35 struct RngRequest 36 { 37 EntropyReceiveFunc *receive_entropy; 38 uint8_t *data; 39 void *opaque; 40 size_t offset; 41 size_t size; 42 QSIMPLEQ_ENTRY(RngRequest) next; 43 }; 44 45 struct RngBackendClass 46 { 47 ObjectClass parent_class; 48 49 void (*request_entropy)(RngBackend *s, RngRequest *req); 50 51 void (*opened)(RngBackend *s, Error **errp); 52 }; 53 54 struct RngBackend 55 { 56 Object parent; 57 58 /*< protected >*/ 59 bool opened; 60 QSIMPLEQ_HEAD(, RngRequest) requests; 61 }; 62 63 64 /** 65 * rng_backend_request_entropy: 66 * @s: the backend to request entropy from 67 * @size: the number of bytes of data to request 68 * @receive_entropy: a function to be invoked when entropy is available 69 * @opaque: data that should be passed to @receive_entropy 70 * 71 * This function is used by the front-end to request entropy from an entropy 72 * source. This function can be called multiple times before @receive_entropy 73 * is invoked with different values of @receive_entropy and @opaque. The 74 * backend will queue each request and handle appropriately. 75 * 76 * The backend does not need to pass the full amount of data to @receive_entropy 77 * but will pass a value greater than 0. 78 */ 79 void rng_backend_request_entropy(RngBackend *s, size_t size, 80 EntropyReceiveFunc *receive_entropy, 81 void *opaque); 82 83 /** 84 * rng_backend_free_request: 85 * @s: the backend that created the request 86 * @req: the request to finalize 87 * 88 * Used by child rng backend classes to finalize requests once they've been 89 * processed. The request is removed from the list of active requests and 90 * deleted. 91 */ 92 void rng_backend_finalize_request(RngBackend *s, RngRequest *req); 93 #endif 94