| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| |
| #include <stdint.h> |
| #include <assert.h> |
| #include <string.h> |
| #include "syscfg/syscfg.h" |
| #include "os/os.h" |
| #include "nimble/ble.h" |
| #include "nimble/nimble_opt.h" |
| #include "controller/ble_hw.h" |
| #include "controller/ble_ll.h" |
| #if MYNEWT_VAL(TRNG) |
| #include "trng/trng.h" |
| #endif |
| |
| #if MYNEWT_VAL(TRNG) |
| static struct trng_dev *g_trng; |
| #else |
| /* This is a simple circular buffer for holding N samples of random data */ |
| struct ble_ll_rnum_data |
| { |
| uint8_t *rnd_in; |
| uint8_t *rnd_out; |
| volatile uint8_t rnd_size; |
| }; |
| |
| struct ble_ll_rnum_data g_ble_ll_rnum_data; |
| uint8_t g_ble_ll_rnum_buf[MYNEWT_VAL(BLE_LL_RNG_BUFSIZE)]; |
| |
| #define IS_RNUM_BUF_END(x) \ |
| (x == &g_ble_ll_rnum_buf[MYNEWT_VAL(BLE_LL_RNG_BUFSIZE) - 1]) |
| |
| void |
| ble_ll_rand_sample(uint8_t rnum) |
| { |
| os_sr_t sr; |
| |
| OS_ENTER_CRITICAL(sr); |
| if (g_ble_ll_rnum_data.rnd_size < MYNEWT_VAL(BLE_LL_RNG_BUFSIZE)) { |
| ++g_ble_ll_rnum_data.rnd_size; |
| g_ble_ll_rnum_data.rnd_in[0] = rnum; |
| if (IS_RNUM_BUF_END(g_ble_ll_rnum_data.rnd_in)) { |
| g_ble_ll_rnum_data.rnd_in = g_ble_ll_rnum_buf; |
| } else { |
| ++g_ble_ll_rnum_data.rnd_in; |
| } |
| } else { |
| /* Stop generating random numbers as we are full */ |
| ble_hw_rng_stop(); |
| } |
| OS_EXIT_CRITICAL(sr); |
| } |
| #endif |
| |
| /* Get 'len' bytes of random data */ |
| int |
| ble_ll_rand_data_get(uint8_t *buf, uint8_t len) |
| { |
| #if MYNEWT_VAL(TRNG) |
| size_t num; |
| |
| while (len) { |
| num = trng_read(g_trng, buf, len); |
| buf += num; |
| len -= num; |
| } |
| #else |
| uint8_t rnums; |
| os_sr_t sr; |
| |
| while (len != 0) { |
| OS_ENTER_CRITICAL(sr); |
| rnums = g_ble_ll_rnum_data.rnd_size; |
| if (rnums > len) { |
| rnums = len; |
| } |
| len -= rnums; |
| g_ble_ll_rnum_data.rnd_size -= rnums; |
| while (rnums) { |
| buf[0] = g_ble_ll_rnum_data.rnd_out[0]; |
| if (IS_RNUM_BUF_END(g_ble_ll_rnum_data.rnd_out)) { |
| g_ble_ll_rnum_data.rnd_out = g_ble_ll_rnum_buf; |
| } else { |
| ++g_ble_ll_rnum_data.rnd_out; |
| } |
| ++buf; |
| --rnums; |
| } |
| OS_EXIT_CRITICAL(sr); |
| |
| /* Make sure rng is started! */ |
| ble_hw_rng_start(); |
| |
| /* Wait till bytes are in buffer. */ |
| if (len) { |
| while ((g_ble_ll_rnum_data.rnd_size < len) && |
| (g_ble_ll_rnum_data.rnd_size < MYNEWT_VAL(BLE_LL_RNG_BUFSIZE))) { |
| /* Spin here */ |
| } |
| } |
| } |
| #endif |
| return BLE_ERR_SUCCESS; |
| } |
| |
| /** |
| * Called to obtain a "prand" as defined in core V4.2 Vol 6 Part B 1.3.2.2 |
| * |
| * @param prand |
| */ |
| void |
| ble_ll_rand_prand_get(uint8_t *prand) |
| { |
| uint16_t sum; |
| |
| while (1) { |
| /* Get 24 bits of random data */ |
| ble_ll_rand_data_get(prand, 3); |
| |
| /* Prand cannot be all zeros or 1's. */ |
| sum = prand[0] + prand[1] + prand[2]; |
| if ((sum != 0) && (sum != (3 * 0xff))) { |
| break; |
| } |
| } |
| |
| /* Upper two bits must be 01 */ |
| prand[2] &= ~0xc0; |
| prand[2] |= 0x40; |
| } |
| |
| /** |
| * Start the generation of random numbers |
| * |
| * @return int |
| */ |
| int |
| ble_ll_rand_start(void) |
| { |
| #if MYNEWT_VAL(TRNG) |
| /* Nothing to do - this is handled by driver */ |
| #else |
| /* Start the generation of numbers if we are not full */ |
| if (g_ble_ll_rnum_data.rnd_size < MYNEWT_VAL(BLE_LL_RNG_BUFSIZE)) { |
| ble_hw_rng_start(); |
| } |
| #endif |
| return 0; |
| } |
| |
| /** |
| * Initialize LL random number generation. Should be called only once on |
| * initialization. |
| * |
| * @return int |
| */ |
| int |
| ble_ll_rand_init(void) |
| { |
| #if MYNEWT_VAL(TRNG) |
| g_trng = (struct trng_dev *) os_dev_open("trng", OS_TIMEOUT_NEVER, NULL); |
| #else |
| g_ble_ll_rnum_data.rnd_in = g_ble_ll_rnum_buf; |
| g_ble_ll_rnum_data.rnd_out = g_ble_ll_rnum_buf; |
| ble_hw_rng_init(ble_ll_rand_sample, 1); |
| #endif |
| return 0; |
| } |