From f36e0c51177979c57b3402676fe342c180f9cb5b Mon Sep 17 00:00:00 2001 From: Sadeep Madurange Date: Mon, 7 Apr 2025 18:09:48 +0800 Subject: Keygen using timer. --- lock/Back.Makefile | 2 +- lock/Frnt.Makefile | 2 +- lock/back.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++-------- lock/frnt.c | 1 + lock/nrfm.c | 3 +-- lock/util.c | 2 +- lock/util.h | 2 ++ 7 files changed, 60 insertions(+), 14 deletions(-) diff --git a/lock/Back.Makefile b/lock/Back.Makefile index 00e72fd..9f2fe2b 100644 --- a/lock/Back.Makefile +++ b/lock/Back.Makefile @@ -2,7 +2,7 @@ CC = avr-gcc MCU = atmega328p TARGET = sender -SRC = back.c uart.c nrfm.c +SRC = back.c uart.c nrfm.c util.c OBJ = $(SRC:.c=.o) CFLAGS = -std=gnu99 diff --git a/lock/Frnt.Makefile b/lock/Frnt.Makefile index 908f4d8..cb957df 100644 --- a/lock/Frnt.Makefile +++ b/lock/Frnt.Makefile @@ -2,7 +2,7 @@ CC = avr-gcc MCU = atmega328p TARGET = app -SRC = frnt.c uart.c nrfm.c +SRC = frnt.c uart.c nrfm.c util.c OBJ = $(SRC:.c=.o) CFLAGS = -std=gnu99 diff --git a/lock/back.c b/lock/back.c index 9da6688..f373d20 100644 --- a/lock/back.c +++ b/lock/back.c @@ -3,6 +3,7 @@ #include #include +#include #include #include @@ -10,16 +11,30 @@ #include "uart.h" #include "util.h" -#define RX_PIN PD7 -#define RX_DDR DDRD -#define RX_PORT PORTD -#define RX_PCIE PCIE2 -#define RX_PCINT PCINT23 -#define RX_PCMSK PCMSK2 -#define RX_PCINTVEC PCINT2_vect +#define PWM_MIN 500 +#define PWM_MID 1500 +#define PWM_MAX 2500 +#define PWM_TOP 20000 + +#define RX_PIN PD7 +#define RX_DDR DDRD +#define RX_PORT PORTD +#define RX_PCIE PCIE2 +#define RX_PCINT PCINT23 +#define RX_PCMSK PCMSK2 +#define RX_PCINTVEC PCINT2_vect + +static char chars[] = { + '0', '8', '3', '6', 'a', 'Z', '$', '4', 'v', 'R', '@', + 'E', '1', 'o', '#', ')', '2', '5', 'q', ';', '.', 'I', + 'c', '7', '9', '*', 'L', 'V', '&', 'k', 'K', '!', 'm', + 'N', '(', 'O', 'Q', 'A', '>', 'T', 't', '?', 'S', 'h', + 'w', '/', 'n', 'W', 'l', 'M', 'e', 'H', 'j', 'g', '[', + 'P', 'f', ':', 'B', ']', 'Y', '^', 'F', '%', 'C', 'x' +}; -// todo: atomic var static volatile int rxdr = 0; +static uint8_t charslen = sizeof(chars) / sizeof(chars[0]); static inline void await_reply(void) { @@ -30,8 +45,32 @@ static inline void await_reply(void) _delay_ms(100); } +static inline void keygen(char *buf, uint8_t n) +{ + int i; + uint8_t sreg; + uint16_t idx; + + sreg = SREG; + cli(); + idx = TCNT1; + SREG = sreg; + + for (i = 0; i < n; i++, idx++) + buf[i] = chars[(idx % charslen)] ; + buf[n - 1] = '\0'; +} + +static inline void timer_init(void) +{ + TCCR1A |= (1 << WGM11) | (1 << COM1A1); + TCCR1B |= (1 << WGM13) | (1 << CS11); + ICR1 = PWM_TOP; /* we use the same timer for servo's PWM */ +} + int main(void) { + uint8_t n; uint8_t rxaddr[ADDRLEN] = { 194, 178, 83 }; uint8_t txaddr[ADDRLEN] = { 194, 178, 82 }; @@ -45,6 +84,7 @@ int main(void) RX_PCMSK |= (1 << RX_PCINT); uart_init(); + timer_init(); radio_init(rxaddr); radio_print_config(); @@ -58,6 +98,10 @@ int main(void) rxdr = 0; xor(KEY, buf, msg, WDLEN); if (strncmp(msg, SYN, WDLEN) == 0) { + keygen(key, WDLEN); + uart_write("DEBUG: session key = "); + uart_write_line(key); + xor(KEY, key, msg, WDLEN); radio_sendto(txaddr, msg, WDLEN); await_reply(); @@ -79,7 +123,7 @@ int main(void) uart_write_line("ERROR: handshake failed"); } } else { - uart_write_line("No IRQ"); + uart_write_line("DEBUG: no new packets"); _delay_ms(2000); } } diff --git a/lock/frnt.c b/lock/frnt.c index 88ee614..c3c36a7 100644 --- a/lock/frnt.c +++ b/lock/frnt.c @@ -31,6 +31,7 @@ static inline void await_reply(void) int main(void) { + uint8_t n; uint8_t rxaddr[ADDRLEN] = { 194, 178, 82 }; uint8_t txaddr[ADDRLEN] = { 194, 178, 83 }; diff --git a/lock/nrfm.c b/lock/nrfm.c index 00127ee..efab531 100644 --- a/lock/nrfm.c +++ b/lock/nrfm.c @@ -290,8 +290,7 @@ void radio_listen(void) uint8_t radio_recv(char *buf, uint8_t n) { - char s[5]; - uint8_t rxdr, readlen, pdlen, maxlen; + uint8_t readlen, pdlen, maxlen; pdlen = 0; disable_chip(); diff --git a/lock/util.c b/lock/util.c index e9a7a5a..95bef77 100644 --- a/lock/util.c +++ b/lock/util.c @@ -1,6 +1,6 @@ #include "util.h" -void xor(const char *k, const char *s, char *d, int n) +void xor(const char *k, const char *s, char *d, uint8_t n) { int i; diff --git a/lock/util.h b/lock/util.h index 64f6ad5..8be238a 100644 --- a/lock/util.h +++ b/lock/util.h @@ -1,6 +1,8 @@ #ifndef MY_UTIL_H #define MY_UTIL_H +#include + #define WDLEN 32 #define KEY "dM>}jdb,6gsnC$J^K 8(I5vyPemPs%;K" -- cgit v1.2.3