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 OBJECT_DECLARE_TYPE(RngBackend, RngBackendClass, 21 RNG_BACKEND) 22 23 #define TYPE_RNG_BUILTIN "rng-builtin" 24 25 typedef struct RngRequest RngRequest; 26 27 typedef void (EntropyReceiveFunc)(void *opaque, 28 const void *data, 29 size_t size); 30 31 struct 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 41 struct 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 50 struct 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 */ 75 void 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 */ 88 void rng_backend_finalize_request(RngBackend *s, RngRequest *req); 89 #endif 90