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csp_if_kiss.c
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csp_if_kiss.c
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/*
Cubesat Space Protocol - A small network-layer protocol designed for Cubesats
Copyright (C) 2012 GomSpace ApS (http://www.gomspace.com)
Copyright (C) 2012 AAUSAT3 Project (http://aausat3.space.aau.dk)
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <inttypes.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <csp/csp.h>
#include <csp/csp_endian.h>
#include <csp/csp_platform.h>
#include <csp/csp_interface.h>
#include <csp/interfaces/csp_if_kiss.h>
#include <csp/arch/csp_semaphore.h>
#include <csp/csp_crc32.h>
#define KISS_MTU 256
#define FEND 0xC0
#define FESC 0xDB
#define TFEND 0xDC
#define TFESC 0xDD
#define TNC_DATA 0x00
#define TNC_SET_HARDWARE 0x06
#define TNC_RETURN 0xFF
static int kiss_lock_init = 0;
static csp_bin_sem_handle_t kiss_lock;
/* Send a CSP packet over the KISS RS232 protocol */
static int csp_kiss_tx(csp_iface_t * interface, csp_packet_t * packet, uint32_t timeout) {
if (interface == NULL || interface->driver == NULL)
return CSP_ERR_DRIVER;
/* Add CRC32 checksum */
csp_crc32_append(packet, false);
/* Save the outgoing id in the buffer */
packet->id.ext = csp_hton32(packet->id.ext);
packet->length += sizeof(packet->id.ext);
/* Lock */
csp_bin_sem_wait(&kiss_lock, 1000);
/* Transmit data */
csp_kiss_handle_t * driver = interface->driver;
driver->kiss_putc(FEND);
driver->kiss_putc(TNC_DATA);
for (unsigned int i = 0; i < packet->length; i++) {
if (((unsigned char *) &packet->id.ext)[i] == FEND) {
((unsigned char *) &packet->id.ext)[i] = TFEND;
driver->kiss_putc(FESC);
} else if (((unsigned char *) &packet->id.ext)[i] == FESC) {
((unsigned char *) &packet->id.ext)[i] = TFESC;
driver->kiss_putc(FESC);
}
driver->kiss_putc(((unsigned char *) &packet->id.ext)[i]);
}
driver->kiss_putc(FEND);
/* Free data */
csp_buffer_free(packet);
/* Unlock */
csp_bin_sem_post(&kiss_lock);
return CSP_ERR_NONE;
}
/**
* When a frame is received, decode the kiss-stuff
* and eventually send it directly to the CSP new packet function.
*/
void csp_kiss_rx(csp_iface_t * interface, uint8_t * buf, int len, void * pxTaskWoken) {
/* Driver handle */
csp_kiss_handle_t * driver = interface->driver;
while (len--) {
/* Input */
unsigned char inputbyte = *buf++;
/* If packet was too long */
if (driver->rx_length > interface->mtu + CSP_HEADER_LENGTH) {
csp_log_warn("KISS RX overflow");
interface->rx_error++;
driver->rx_mode = KISS_MODE_NOT_STARTED;
driver->rx_length = 0;
}
switch (driver->rx_mode) {
case KISS_MODE_NOT_STARTED:
/* Send normal chars back to usart driver */
if (inputbyte != FEND) {
if (driver->kiss_discard != NULL)
driver->kiss_discard(inputbyte, pxTaskWoken);
break;
}
/* Try to allocate new buffer */
if (driver->rx_packet == NULL) {
if (pxTaskWoken == NULL) {
driver->rx_packet = csp_buffer_get(interface->mtu);
} else {
driver->rx_packet = csp_buffer_get_isr(interface->mtu);
}
}
/* If no more memory, skip frame */
if (driver->rx_packet == NULL) {
driver->rx_mode = KISS_MODE_SKIP_FRAME;
break;
}
/* Start transfer */
driver->rx_length = 0;
driver->rx_mode = KISS_MODE_STARTED;
driver->rx_first = 1;
break;
case KISS_MODE_STARTED:
/* Escape char */
if (inputbyte == FESC) {
driver->rx_mode = KISS_MODE_ESCAPED;
break;
}
/* End Char */
if (inputbyte == FEND) {
/* Accept message */
if (driver->rx_length > 0) {
/* Check for valid length */
if (driver->rx_length < CSP_HEADER_LENGTH + sizeof(uint32_t)) {
csp_log_warn("KISS short frame skipped, len: %u", driver->rx_length);
interface->rx_error++;
driver->rx_mode = KISS_MODE_NOT_STARTED;
break;
}
/* Count received frame */
interface->frame++;
/* The CSP packet length is without the header */
driver->rx_packet->length = driver->rx_length - CSP_HEADER_LENGTH;
/* Convert the packet from network to host order */
driver->rx_packet->id.ext = csp_ntoh32(driver->rx_packet->id.ext);
/* Validate CRC */
if (csp_crc32_verify(driver->rx_packet, false) != CSP_ERR_NONE) {
csp_log_warn("KISS invalid crc frame skipped, len: %u", driver->rx_packet->length);
interface->rx_error++;
driver->rx_mode = KISS_MODE_NOT_STARTED;
break;
}
/* Send back into CSP, notice calling from task so last argument must be NULL! */
csp_qfifo_write(driver->rx_packet, interface, pxTaskWoken);
driver->rx_packet = NULL;
driver->rx_mode = KISS_MODE_NOT_STARTED;
break;
}
/* Break after the end char */
break;
}
/* Skip the first char after FEND which is TNC_DATA (0x00) */
if (driver->rx_first) {
driver->rx_first = 0;
break;
}
/* Valid data char */
((char *) &driver->rx_packet->id.ext)[driver->rx_length++] = inputbyte;
break;
case KISS_MODE_ESCAPED:
/* Escaped escape char */
if (inputbyte == TFESC)
((char *) &driver->rx_packet->id.ext)[driver->rx_length++] = FESC;
/* Escaped fend char */
if (inputbyte == TFEND)
((char *) &driver->rx_packet->id.ext)[driver->rx_length++] = FEND;
/* Go back to started mode */
driver->rx_mode = KISS_MODE_STARTED;
break;
case KISS_MODE_SKIP_FRAME:
/* Just wait for end char */
if (inputbyte == FEND)
driver->rx_mode = KISS_MODE_NOT_STARTED;
break;
}
}
}
void csp_kiss_init(csp_iface_t * csp_iface, csp_kiss_handle_t * csp_kiss_handle, csp_kiss_putc_f kiss_putc_f, csp_kiss_discard_f kiss_discard_f, const char * name) {
/* Init lock only once */
if (kiss_lock_init == 0) {
csp_bin_sem_create(&kiss_lock);
kiss_lock_init = 1;
}
/* Register device handle as member of interface */
csp_iface->driver = csp_kiss_handle;
csp_kiss_handle->kiss_discard = kiss_discard_f;
csp_kiss_handle->kiss_putc = kiss_putc_f;
csp_kiss_handle->rx_packet = NULL;
csp_kiss_handle->rx_mode = KISS_MODE_NOT_STARTED;
/* Setop other mandatories */
csp_iface->mtu = KISS_MTU;
csp_iface->nexthop = csp_kiss_tx;
csp_iface->name = name;
/* Regsiter interface */
csp_iflist_add(csp_iface);
}