| 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 | |
| 90 | /** |
| 91 | * rng_backend_cancel_requests: |
| 92 | * @s: the backend that created the request |
| 93 | * @receive_entropy: the function invoked when entropy is available |
| 94 | * @opaque: data passed to @receive_entropy |
| 95 | * |
| 96 | * This function is used by the front-end to cancel all requests to a |
| 97 | * given backend. Requests to cancel are identified by the receive_entropy |
| 98 | * function and the data passed to the function. |
| 99 | */ |
| 100 | void rng_backend_cancel_requests(RngBackend *s, |
| 101 | EntropyReceiveFunc *receive_entropy, |
| 102 | const void *opaque); |
| 103 | #endif |