/* * neug.c - true random number generation * * Copyright (C) 2011, 2012, 2013, 2016, 2017 * Free Software Initiative of Japan * Author: NIIBE Yutaka * * This file is a part of NeuG, a True Random Number Generator * implementation based on quantization error of ADC (for STM32F103). * * NeuG is free software: you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * NeuG is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public * License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . * */ #include #include #include #include "sys.h" #include "neug.h" #ifndef GNU_LINUX_EMULATION #include "mcu/stm32f103.h" #endif #include "adc.h" #include "sha256.h" #ifdef GNU_LINUX_EMULATION static const uint32_t crc32_rv_table[256] = { 0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005, 0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61, 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd, 0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75, 0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd, 0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039, 0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5, 0xbe2b5b58, 0xbaea46ef, 0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d, 0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49, 0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95, 0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, 0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d, 0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072, 0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16, 0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca, 0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde, 0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02, 0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba, 0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b, 0xbb60adfc, 0xb6238b25, 0xb2e29692, 0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6, 0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a, 0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e, 0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2, 0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a, 0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637, 0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb, 0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, 0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53, 0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5, 0x3f9b762c, 0x3b5a6b9b, 0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff, 0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623, 0xf12f560e, 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b, 0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f, 0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3, 0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, 0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b, 0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3, 0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640, 0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c, 0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8, 0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24, 0x119b4be9, 0x155a565e, 0x18197087, 0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec, 0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d, 0x2056cd3a, 0x2d15ebe3, 0x29d4f654, 0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0, 0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c, 0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18, 0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4, 0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c, 0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668, 0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4 }; static uint32_t crc; void crc32_rv_reset (void) { crc = 0xffffffff; } void crc32_rv_step (uint32_t v) { crc = crc32_rv_table[(crc ^ (v << 0)) >> 24] ^ (crc << 8); crc = crc32_rv_table[(crc ^ (v << 8)) >> 24] ^ (crc << 8); crc = crc32_rv_table[(crc ^ (v << 16)) >> 24] ^ (crc << 8); crc = crc32_rv_table[(crc ^ (v << 24)) >> 24] ^ (crc << 8); } uint32_t crc32_rv_get (void) { return crc; } uint32_t rbit (uint32_t v) { v = ((v >> 1) & 0x55555555) | ((v & 0x55555555) << 1); v = ((v >> 2) & 0x33333333) | ((v & 0x33333333) << 2); v = ((v >> 4) & 0x0F0F0F0F) | ((v & 0x0F0F0F0F) << 4); v = ((v >> 8) & 0x00FF00FF) | ((v & 0x00FF00FF) << 8); v = ( v >> 16 ) | ( v << 16); return v; } #else void crc32_rv_reset (void) { RCC->AHBENR |= RCC_AHBENR_CRCEN; CRC->CR = CRC_CR_RESET; } void crc32_rv_step (uint32_t v) { CRC->DR = v; } uint32_t crc32_rv_get (void) { return CRC->DR; } uint32_t rbit (uint32_t v) { uint32_t r; asm ("rbit %0, %1" : "=r" (r) : "r" (v)); return r; } #endif static chopstx_mutex_t mode_mtx; static chopstx_cond_t mode_cond; static sha256_context sha256_ctx_data; static uint32_t sha256_output[SHA256_DIGEST_SIZE/sizeof (uint32_t)]; /* * To be a full entropy source, the requirement is to have N samples * for output of 256-bit, where: * * N = (256 * 2) / * * For example, N should be more than 103 for min-entropy = 5.0. * * On the other hand, in the section 6.2 "Full Entropy Source * Requirements", it says: * * At least twice the block size of the underlying cryptographic * primitive shall be provided as input to the conditioning * function to produce full entropy output. * * For us, cryptographic primitive is SHA-256 and its blocksize is * 512-bit (64-byte), thus, N >= 128. * * We chose N=140. Note that we have "additional bits" of 16-byte for * last block (feedback from previous output of SHA-256) to feed * hash_df function of SHA-256, together with sample data of 140-byte. * * N=140 corresponds to min-entropy >= 3.68. * */ #define NUM_NOISE_INPUTS 140 #define EP_ROUND_0 0 /* initial-five-byte and 3-byte, then 56-byte-input */ #define EP_ROUND_1 1 /* 64-byte-input */ #define EP_ROUND_2 2 /* 17-byte-input */ #define EP_ROUND_RAW 3 /* 32-byte-input */ #define EP_ROUND_RAW_DATA 4 /* 32-byte-input */ #define EP_ROUND_0_INPUTS 56 #define EP_ROUND_1_INPUTS 64 #define EP_ROUND_2_INPUTS 17 #define EP_ROUND_RAW_INPUTS 32 #define EP_ROUND_RAW_DATA_INPUTS 32 static uint8_t ep_round; static void noise_source_continuous_test (uint8_t noise); static void noise_source_continuous_test_word (uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3); /* * Hash_df initial string: * * Initial five bytes are: * 1, : counter = 1 * 0, 0, 1, 0 : no_of_bits_returned (in big endian) * * Then, three-byte from noise source follows. * * One-byte was used in the previous turn, and we have three bytes in * CRC32. */ static void ep_fill_initial_string (void) { uint32_t v = crc32_rv_get (); uint8_t b1, b2, b3; b3 = v >> 24; b2 = v >> 16; b1 = v >> 8; noise_source_continuous_test (b1); noise_source_continuous_test (b2); noise_source_continuous_test (b3); adc_buf[0] = 0x01000001; adc_buf[1] = (v & 0xffffff00); } static void ep_init (int mode) { if (mode == NEUG_MODE_RAW) { ep_round = EP_ROUND_RAW; adc_start_conversion (0, EP_ROUND_RAW_INPUTS); } else if (mode == NEUG_MODE_RAW_DATA) { ep_round = EP_ROUND_RAW_DATA; adc_start_conversion (0, EP_ROUND_RAW_DATA_INPUTS / 4); } else { ep_round = EP_ROUND_0; ep_fill_initial_string (); adc_start_conversion (2, EP_ROUND_0_INPUTS); } } static void ep_fill_wbuf_v (int i, int test, uint32_t v) { if (test) { uint8_t b0, b1, b2, b3; b3 = v >> 24; b2 = v >> 16; b1 = v >> 8; b0 = v; noise_source_continuous_test_word (b0, b1, b2, b3); } sha256_ctx_data.wbuf[i] = v; } /* Here, we assume a little endian architecture. */ static int ep_process (int mode) { int i, n; uint32_t v; if (ep_round == EP_ROUND_0) { sha256_start (&sha256_ctx_data); sha256_ctx_data.wbuf[0] = adc_buf[0]; sha256_ctx_data.wbuf[1] = adc_buf[1]; for (i = 0; i < EP_ROUND_0_INPUTS / 4; i++) { crc32_rv_step (adc_buf[i*4 + 2]); crc32_rv_step (adc_buf[i*4 + 3]); crc32_rv_step (adc_buf[i*4 + 4]); crc32_rv_step (adc_buf[i*4 + 5]); v = crc32_rv_get (); ep_fill_wbuf_v (i+2, 1, v); } adc_start_conversion (0, EP_ROUND_1_INPUTS); sha256_process (&sha256_ctx_data); ep_round++; return 0; } else if (ep_round == EP_ROUND_1) { for (i = 0; i < EP_ROUND_1_INPUTS / 4; i++) { crc32_rv_step (adc_buf[i*4]); crc32_rv_step (adc_buf[i*4 + 1]); crc32_rv_step (adc_buf[i*4 + 2]); crc32_rv_step (adc_buf[i*4 + 3]); v = crc32_rv_get (); ep_fill_wbuf_v (i, 1, v); } adc_start_conversion (0, EP_ROUND_2_INPUTS + 3); sha256_process (&sha256_ctx_data); ep_round++; return 0; } else if (ep_round == EP_ROUND_2) { for (i = 0; i < EP_ROUND_2_INPUTS / 4; i++) { crc32_rv_step (adc_buf[i*4]); crc32_rv_step (adc_buf[i*4 + 1]); crc32_rv_step (adc_buf[i*4 + 2]); crc32_rv_step (adc_buf[i*4 + 3]); v = crc32_rv_get (); ep_fill_wbuf_v (i, 1, v); } crc32_rv_step (adc_buf[i*4]); crc32_rv_step (adc_buf[i*4 + 1]); crc32_rv_step (adc_buf[i*4 + 2]); crc32_rv_step (adc_buf[i*4 + 3]); v = crc32_rv_get () & 0xff; /* First byte of CRC32 is used here. */ noise_source_continuous_test (v); sha256_ctx_data.wbuf[i] = v; ep_init (NEUG_MODE_CONDITIONED); /* The rest three-byte of CRC32 is used here. */ n = SHA256_DIGEST_SIZE / 2; memcpy (((uint8_t *)sha256_ctx_data.wbuf) + EP_ROUND_2_INPUTS, sha256_output, n); sha256_ctx_data.total[0] = 5 + NUM_NOISE_INPUTS + n; sha256_finish (&sha256_ctx_data, (uint8_t *)sha256_output); return SHA256_DIGEST_SIZE / sizeof (uint32_t); } else if (ep_round == EP_ROUND_RAW) { for (i = 0; i < EP_ROUND_RAW_INPUTS / 4; i++) { crc32_rv_step (adc_buf[i*4]); crc32_rv_step (adc_buf[i*4 + 1]); crc32_rv_step (adc_buf[i*4 + 2]); crc32_rv_step (adc_buf[i*4 + 3]); v = crc32_rv_get (); ep_fill_wbuf_v (i, 1, v); } ep_init (mode); return EP_ROUND_RAW_INPUTS / 4; } else if (ep_round == EP_ROUND_RAW_DATA) { for (i = 0; i < EP_ROUND_RAW_DATA_INPUTS / 4; i++) { v = adc_buf[i]; ep_fill_wbuf_v (i, 0, v); } ep_init (mode); return EP_ROUND_RAW_DATA_INPUTS / 4; } return 0; } static const uint32_t *ep_output (int mode) { if (mode) return sha256_ctx_data.wbuf; else return sha256_output; } #define REPETITION_COUNT 1 #define ADAPTIVE_PROPORTION_64 2 #define ADAPTIVE_PROPORTION_4096 4 uint8_t neug_err_state; uint16_t neug_err_cnt; uint16_t neug_err_cnt_rc; uint16_t neug_err_cnt_p64; uint16_t neug_err_cnt_p4k; uint16_t neug_rc_max; uint16_t neug_p64_max; uint16_t neug_p4k_max; static void noise_source_cnt_max_reset (void) { neug_err_cnt = neug_err_cnt_rc = neug_err_cnt_p64 = neug_err_cnt_p4k = 0; neug_rc_max = neug_p64_max = neug_p4k_max = 0; } static void noise_source_error_reset (void) { neug_err_state = 0; } static void noise_source_error (uint32_t err) { neug_err_state |= err; neug_err_cnt++; if ((err & REPETITION_COUNT)) neug_err_cnt_rc++; if ((err & ADAPTIVE_PROPORTION_64)) neug_err_cnt_p64++; if ((err & ADAPTIVE_PROPORTION_4096)) neug_err_cnt_p4k++; } /* * For health tests, we assume that the device noise source has * min-entropy >= 4.2. Observing raw data stream (before CRC-32) has * more than 4.2 bit/byte entropy. When the data stream after CRC-32 * filter will be less than 4.2 bit/byte entropy, that must be * something wrong. Note that even we observe < 4.2, we still have * some margin, since we use NUM_NOISE_INPUTS=140. * */ /* Cuttoff = 9, when min-entropy = 4.2, W= 2^-30 */ /* ceiling of (1+30/4.2) */ #define REPITITION_COUNT_TEST_CUTOFF 9 static uint8_t rct_a; static uint8_t rct_b; static void repetition_count_test (uint8_t sample) { if (rct_a == sample) { rct_b++; if (rct_b >= REPITITION_COUNT_TEST_CUTOFF) noise_source_error (REPETITION_COUNT); if (rct_b > neug_rc_max) neug_rc_max = rct_b; } else { rct_a = sample; rct_b = 1; } } static void repetition_count_test_word (uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3) { if (rct_a == b0) rct_b++; else { rct_a = b0; rct_b = 1; } if (rct_a == b1) rct_b++; else { rct_a = b1; rct_b = 1; } if (rct_a == b2) rct_b++; else { rct_a = b2; rct_b = 1; } if (rct_a == b3) rct_b++; else { rct_a = b3; rct_b = 1; } if (rct_b >= REPITITION_COUNT_TEST_CUTOFF) noise_source_error (REPETITION_COUNT); if (rct_b > neug_rc_max) neug_rc_max = rct_b; } /* Cuttoff = 18, when min-entropy = 4.2, W= 2^-30 */ /* With R, qbinom(1-2^-30,64,2^-4.2) */ #define ADAPTIVE_PROPORTION_64_TEST_CUTOFF 18 static uint8_t ap64t_a; static uint8_t ap64t_b; static uint8_t ap64t_s; static void adaptive_proportion_64_test (uint8_t sample) { if (ap64t_s++ >= 64) { ap64t_a = sample; ap64t_s = 1; ap64t_b = 0; } else if (ap64t_a == sample) { ap64t_b++; if (ap64t_b > ADAPTIVE_PROPORTION_64_TEST_CUTOFF) noise_source_error (ADAPTIVE_PROPORTION_64); if (ap64t_b > neug_p64_max) neug_p64_max = ap64t_b; } } static void adaptive_proportion_64_test_word (uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3) { if (ap64t_s >= 64) { ap64t_a = b0; ap64t_s = 4; ap64t_b = 0; } else { ap64t_s += 4; if (ap64t_a == b0) ap64t_b++; } if (ap64t_a == b1) ap64t_b++; if (ap64t_a == b2) ap64t_b++; if (ap64t_a == b3) ap64t_b++; if (ap64t_b > ADAPTIVE_PROPORTION_64_TEST_CUTOFF) noise_source_error (ADAPTIVE_PROPORTION_64); if (ap64t_b > neug_p64_max) neug_p64_max = ap64t_b; } /* Cuttoff = 315, when min-entropy = 4.2, W= 2^-30 */ /* With R, qbinom(1-2^-30,4096,2^-4.2) */ #define ADAPTIVE_PROPORTION_4096_TEST_CUTOFF 315 static uint8_t ap4096t_a; static uint16_t ap4096t_b; static uint16_t ap4096t_s; static void adaptive_proportion_4096_test (uint8_t sample) { if (ap4096t_s++ >= 4096) { ap4096t_a = sample; ap4096t_s = 1; ap4096t_b = 0; } else if (ap4096t_a == sample) { ap4096t_b++; if (ap4096t_b > ADAPTIVE_PROPORTION_4096_TEST_CUTOFF) noise_source_error (ADAPTIVE_PROPORTION_4096); if (ap4096t_b > neug_p4k_max) neug_p4k_max = ap4096t_b; } } static void adaptive_proportion_4096_test_word (uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3) { if (ap4096t_s >= 4096) { ap4096t_a = b0; ap4096t_s = 4; ap4096t_b = 0; } else { ap4096t_s += 4; if (ap4096t_a == b0) ap4096t_b++; } if (ap4096t_a == b1) ap4096t_b++; if (ap4096t_a == b2) ap4096t_b++; if (ap4096t_a == b3) ap4096t_b++; if (ap4096t_b > ADAPTIVE_PROPORTION_4096_TEST_CUTOFF) noise_source_error (ADAPTIVE_PROPORTION_4096); if (ap4096t_b > neug_p4k_max) neug_p4k_max = ap4096t_b; } static void noise_source_continuous_test (uint8_t noise) { repetition_count_test (noise); adaptive_proportion_64_test (noise); adaptive_proportion_4096_test (noise); } static void noise_source_continuous_test_word (uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3) { repetition_count_test_word (b0, b1, b2, b3); adaptive_proportion_64_test_word (b0, b1, b2, b3); adaptive_proportion_4096_test_word (b0, b1, b2, b3); } /* * Ring buffer, filled by generator, consumed by neug_get routine. */ struct rng_rb { uint32_t *buf; chopstx_mutex_t m; chopstx_cond_t data_available; chopstx_cond_t space_available; uint8_t head, tail; uint8_t size; unsigned int full :1; unsigned int empty :1; }; static void rb_init (struct rng_rb *rb, uint32_t *p, uint8_t size) { rb->buf = p; rb->size = size; chopstx_mutex_init (&rb->m); chopstx_cond_init (&rb->data_available); chopstx_cond_init (&rb->space_available); rb->head = rb->tail = 0; rb->full = 0; rb->empty = 1; } static void rb_add (struct rng_rb *rb, uint32_t v) { rb->buf[rb->tail++] = v; if (rb->tail == rb->size) rb->tail = 0; if (rb->tail == rb->head) rb->full = 1; rb->empty = 0; } static uint32_t rb_del (struct rng_rb *rb) { uint32_t v = rb->buf[rb->head++]; if (rb->head == rb->size) rb->head = 0; if (rb->head == rb->tail) rb->empty = 1; rb->full = 0; return v; } uint8_t neug_mode; static int rng_should_terminate; static chopstx_t rng_thread; /** * @brief Random number generation thread. */ static void * rng (void *arg) { struct rng_rb *rb = (struct rng_rb *)arg; int mode = neug_mode; rng_should_terminate = 0; chopstx_mutex_init (&mode_mtx); chopstx_cond_init (&mode_cond); /* Enable ADCs */ adc_start (); ep_init (mode); while (!rng_should_terminate) { int err; int n; err = adc_wait_completion (); chopstx_mutex_lock (&mode_mtx); if (err || mode != neug_mode) { mode = neug_mode; noise_source_cnt_max_reset (); /* Discarding data available, re-initiate from the start. */ ep_init (mode); chopstx_cond_signal (&mode_cond); chopstx_mutex_unlock (&mode_mtx); continue; } else chopstx_mutex_unlock (&mode_mtx); if ((n = ep_process (mode))) { int i; const uint32_t *vp; if (neug_err_state != 0 && (mode == NEUG_MODE_CONDITIONED || mode == NEUG_MODE_RAW)) { /* Don't use the result and do it again. */ noise_source_error_reset (); continue; } vp = ep_output (mode); chopstx_mutex_lock (&rb->m); while (rb->full) chopstx_cond_wait (&rb->space_available, &rb->m); for (i = 0; i < n; i++) { rb_add (rb, *vp++); if (rb->full) break; } chopstx_cond_signal (&rb->data_available); chopstx_mutex_unlock (&rb->m); } } adc_stop (); return NULL; } static struct rng_rb the_ring_buffer; #define STACK_PROCESS_2 #include "stack-def.h" #define STACK_ADDR_RNG ((uintptr_t)process2_base) #define STACK_SIZE_RNG (sizeof process2_base) #define PRIO_RNG 2 /** * @brief Initialize NeuG. */ void neug_init (uint32_t *buf, uint8_t size) { const uint32_t *u = (const uint32_t *)unique_device_id (); struct rng_rb *rb = &the_ring_buffer; int i; crc32_rv_reset (); /* * This initialization ensures that it generates different sequence * even if all physical conditions are same. */ for (i = 0; i < 3; i++) crc32_rv_step (*u++); neug_mode = NEUG_MODE_CONDITIONED; rb_init (rb, buf, size); rng_thread = chopstx_create (PRIO_RNG, STACK_ADDR_RNG, STACK_SIZE_RNG, rng, rb); } /** * @breif Flush random bytes. */ void neug_flush (void) { struct rng_rb *rb = &the_ring_buffer; chopstx_mutex_lock (&rb->m); while (!rb->empty) (void)rb_del (rb); chopstx_cond_signal (&rb->space_available); chopstx_mutex_unlock (&rb->m); } /** * @brief Wakes up RNG thread to generate random numbers. */ void neug_kick_filling (void) { struct rng_rb *rb = &the_ring_buffer; chopstx_mutex_lock (&rb->m); if (!rb->full) chopstx_cond_signal (&rb->space_available); chopstx_mutex_unlock (&rb->m); } /** * @brief Get random word (32-bit) from NeuG. * @detail With NEUG_KICK_FILLING, it wakes up RNG thread. * With NEUG_NO_KICK, it doesn't wake up RNG thread automatically, * it is needed to call neug_kick_filling later. */ uint32_t neug_get (int kick) { struct rng_rb *rb = &the_ring_buffer; uint32_t v; chopstx_mutex_lock (&rb->m); while (rb->empty) chopstx_cond_wait (&rb->data_available, &rb->m); v = rb_del (rb); if (kick) chopstx_cond_signal (&rb->space_available); chopstx_mutex_unlock (&rb->m); return v; } int neug_get_nonblock (uint32_t *p) { struct rng_rb *rb = &the_ring_buffer; int r = 0; chopstx_mutex_lock (&rb->m); if (rb->empty) { r = -1; chopstx_cond_signal (&rb->space_available); } else *p = rb_del (rb); chopstx_mutex_unlock (&rb->m); return r; } int neug_consume_random (void (*proc) (uint32_t, int)) { int i = 0; struct rng_rb *rb = &the_ring_buffer; chopstx_mutex_lock (&rb->m); while (!rb->empty) { uint32_t v; v = rb_del (rb); proc (v, i); i++; } chopstx_cond_signal (&rb->space_available); chopstx_mutex_unlock (&rb->m); return i; } void neug_wait_full (void) { struct rng_rb *rb = &the_ring_buffer; chopstx_mutex_lock (&rb->m); while (!rb->full) chopstx_cond_wait (&rb->data_available, &rb->m); chopstx_mutex_unlock (&rb->m); } void neug_fini (void) { rng_should_terminate = 1; neug_get (1); chopstx_join (rng_thread, NULL); } void neug_mode_select (uint8_t mode) { if (neug_mode == mode) return; neug_wait_full (); chopstx_mutex_lock (&mode_mtx); neug_mode = mode; neug_flush (); chopstx_cond_wait (&mode_cond, &mode_mtx); chopstx_mutex_unlock (&mode_mtx); neug_wait_full (); neug_flush (); }