mirror of
https://github.com/f4exb/sdrangel.git
synced 2024-11-13 20:01:46 -05:00
348 lines
11 KiB
C++
348 lines
11 KiB
C++
/*---------------------------------------------------------------------------*\
|
|
|
|
FILE........: freedv_data_channel.c
|
|
AUTHOR......: Jeroen Vreeken
|
|
DATE CREATED: 03 March 2016
|
|
|
|
Data channel for ethernet like packets in freedv VHF frames.
|
|
Currently designed for-
|
|
* 2 control bits per frame
|
|
* 4 byte counter bits per frame
|
|
* 64 bits of data per frame
|
|
\*---------------------------------------------------------------------------*/
|
|
|
|
/*
|
|
Copyright (C) 2016 Jeroen Vreeken
|
|
|
|
All rights reserved.
|
|
|
|
This program is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU Lesser General Public License version 2.1, as
|
|
published by the Free Software Foundation. This program 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 Lesser General Public License
|
|
along with this program; if not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include "freedv_data_channel.h"
|
|
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <cstddef>
|
|
|
|
namespace FreeDV
|
|
{
|
|
|
|
static unsigned char fdc_header_bcast[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
|
|
|
|
/* CCIT CRC table (0x1201 polynomal) */
|
|
static unsigned short fdc_crc_table[256] = {
|
|
0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
|
|
0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
|
|
0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
|
|
0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
|
|
0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
|
|
0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
|
|
0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
|
|
0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
|
|
0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
|
|
0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
|
|
0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
|
|
0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
|
|
0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
|
|
0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
|
|
0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
|
|
0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
|
|
0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
|
|
0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
|
|
0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
|
|
0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
|
|
0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
|
|
0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
|
|
0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
|
|
0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
|
|
0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
|
|
0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
|
|
0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
|
|
0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
|
|
0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
|
|
0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
|
|
0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
|
|
0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
|
|
};
|
|
|
|
static unsigned short fdc_crc(unsigned char *buffer, std::size_t len)
|
|
{
|
|
unsigned short crc = 0xffff;
|
|
std::size_t i;
|
|
|
|
for (i = 0; i < len; i++, buffer++) {
|
|
crc = (crc >> 8) ^ fdc_crc_table[(crc ^ *buffer) & 0xff];
|
|
}
|
|
|
|
return crc ^ 0xffff;
|
|
}
|
|
|
|
/* CRC4 0x03 polynomal */
|
|
static unsigned char fdc_crc4(unsigned char *buffer, std::size_t len)
|
|
{
|
|
unsigned char crc = 0x0f;
|
|
std::size_t i;
|
|
|
|
for (i = 0; i < len; i++, buffer++) {
|
|
int shift;
|
|
|
|
for (shift = 7; shift <= 0; shift--) {
|
|
crc <<= 1;
|
|
if ((*buffer >> shift) & 0x1)
|
|
crc |= 1;
|
|
if (crc & 0x10)
|
|
crc ^= 0x03;
|
|
}
|
|
}
|
|
|
|
return crc & 0x0f;
|
|
}
|
|
|
|
struct freedv_data_channel *freedv_data_channel_create(void)
|
|
{
|
|
struct freedv_data_channel *fdc;
|
|
|
|
fdc = (freedv_data_channel*) malloc(sizeof(struct freedv_data_channel));
|
|
if (!fdc)
|
|
return nullptr;
|
|
|
|
fdc->cb_rx = nullptr;
|
|
fdc->cb_tx = nullptr;
|
|
fdc->packet_tx_size = 0;
|
|
|
|
freedv_data_set_header(fdc, fdc_header_bcast);
|
|
|
|
memcpy(fdc->rx_header, fdc->tx_header, 8);
|
|
|
|
return fdc;
|
|
}
|
|
|
|
void freedv_data_channel_destroy(struct freedv_data_channel *fdc)
|
|
{
|
|
free(fdc);
|
|
}
|
|
|
|
|
|
void freedv_data_set_cb_rx(struct freedv_data_channel *fdc, freedv_data_callback_rx cb, void *state)
|
|
{
|
|
fdc->cb_rx = cb;
|
|
fdc->cb_rx_state = state;
|
|
}
|
|
|
|
void freedv_data_set_cb_tx(struct freedv_data_channel *fdc, freedv_data_callback_tx cb, void *state)
|
|
{
|
|
fdc->cb_tx = cb;
|
|
fdc->cb_tx_state = state;
|
|
}
|
|
|
|
void freedv_data_channel_rx_frame(struct freedv_data_channel *fdc, unsigned char *data, std::size_t size, int from_bit, int bcast_bit, int crc_bit, int end_bits)
|
|
{
|
|
int copy_bits;
|
|
|
|
if (end_bits) {
|
|
copy_bits = end_bits;
|
|
} else {
|
|
copy_bits = size;
|
|
}
|
|
|
|
/* New packet? */
|
|
if (fdc->packet_rx_cnt == 0)
|
|
{
|
|
/* Does the packet have a compressed from field? */
|
|
if (from_bit) {
|
|
/* Compressed from: take the previously received header */
|
|
memcpy(fdc->packet_rx + fdc->packet_rx_cnt, fdc->rx_header, 6);
|
|
fdc->packet_rx_cnt += 6;
|
|
}
|
|
|
|
if (bcast_bit)
|
|
{
|
|
if (!from_bit)
|
|
{
|
|
/* Copy from header and modify size and end_bits accordingly */
|
|
memcpy(fdc->packet_rx + fdc->packet_rx_cnt, data, 6);
|
|
fdc->packet_rx_cnt += 6;
|
|
copy_bits -= 6;
|
|
|
|
if (copy_bits < 0) {
|
|
copy_bits = 0;
|
|
}
|
|
|
|
data += 6;
|
|
}
|
|
/* Compressed to: fill in broadcast address */
|
|
memcpy(fdc->packet_rx + fdc->packet_rx_cnt, fdc_header_bcast, sizeof(fdc_header_bcast));
|
|
fdc->packet_rx_cnt += 6;
|
|
}
|
|
|
|
if (crc_bit)
|
|
{
|
|
unsigned char calc_crc = fdc_crc4(data, size);
|
|
|
|
if (calc_crc == end_bits)
|
|
{
|
|
/* It is a single header field, remember it for later */
|
|
memcpy(fdc->packet_rx + 6, data, 6);
|
|
memcpy(fdc->packet_rx, fdc_header_bcast, 6);
|
|
|
|
if (fdc->cb_rx) {
|
|
fdc->cb_rx(fdc->cb_rx_state, fdc->packet_rx, 12);
|
|
}
|
|
}
|
|
|
|
fdc->packet_rx_cnt = 0;
|
|
return;
|
|
}
|
|
}
|
|
|
|
if (fdc->packet_rx_cnt + copy_bits >= FREEDV_DATA_CHANNEL_PACKET_MAX)
|
|
{
|
|
// Something went wrong... this can not be a real packet
|
|
fdc->packet_rx_cnt = 0;
|
|
return;
|
|
}
|
|
else if (fdc->packet_rx_cnt < 0)
|
|
{
|
|
// This is wrong too...
|
|
fdc->packet_rx_cnt = 0;
|
|
return;
|
|
}
|
|
|
|
memcpy(fdc->packet_rx + fdc->packet_rx_cnt, data, copy_bits);
|
|
fdc->packet_rx_cnt += copy_bits;
|
|
|
|
if (end_bits != 0 && fdc->packet_rx_cnt >= 2)
|
|
{
|
|
unsigned short calc_crc = fdc_crc(fdc->packet_rx, fdc->packet_rx_cnt - 2);
|
|
unsigned short rx_crc;
|
|
rx_crc = fdc->packet_rx[fdc->packet_rx_cnt - 1] << 8;
|
|
rx_crc |= fdc->packet_rx[fdc->packet_rx_cnt - 2];
|
|
|
|
if (rx_crc == calc_crc)
|
|
{
|
|
if ((std::size_t) fdc->packet_rx_cnt == size) {
|
|
/* It is a single header field, remember it for later */
|
|
memcpy(fdc->rx_header, fdc->packet_rx, 6);
|
|
}
|
|
|
|
/* callback */
|
|
if (fdc->cb_rx)
|
|
{
|
|
unsigned char tmp[6];
|
|
memcpy(tmp, fdc->packet_rx, 6);
|
|
memcpy(fdc->packet_rx, fdc->packet_rx + 6, 6);
|
|
memcpy(fdc->packet_rx + 6, tmp, 6);
|
|
std::size_t size = fdc->packet_rx_cnt - 2;
|
|
|
|
if (size < 12) {
|
|
size = 12;
|
|
}
|
|
|
|
fdc->cb_rx(fdc->cb_rx_state, fdc->packet_rx, size);
|
|
}
|
|
}
|
|
|
|
fdc->packet_rx_cnt = 0;
|
|
}
|
|
}
|
|
|
|
void freedv_data_channel_tx_frame(struct freedv_data_channel *fdc, unsigned char *data, std::size_t size, int *from_bit, int *bcast_bit, int *crc_bit, int *end_bits)
|
|
{
|
|
*from_bit = 0;
|
|
*bcast_bit = 0;
|
|
*crc_bit = 0;
|
|
|
|
if (!fdc->packet_tx_size) {
|
|
fdc->packet_tx_cnt = 0;
|
|
|
|
if (fdc->cb_tx) {
|
|
fdc->packet_tx_size = FREEDV_DATA_CHANNEL_PACKET_MAX;
|
|
fdc->cb_tx(fdc->cb_tx_state, fdc->packet_tx, &fdc->packet_tx_size);
|
|
}
|
|
if (!fdc->packet_tx_size) {
|
|
/* Nothing to send, insert a header frame */
|
|
memcpy(fdc->packet_tx, fdc->tx_header, size);
|
|
if (size < 8) {
|
|
*end_bits = fdc_crc4(fdc->tx_header, size);
|
|
*crc_bit = 1;
|
|
memcpy(data, fdc->tx_header, size);
|
|
|
|
return;
|
|
} else {
|
|
fdc->packet_tx_size = size;
|
|
}
|
|
} else {
|
|
/* new packet */
|
|
unsigned short crc;
|
|
unsigned char tmp[6];
|
|
|
|
*from_bit = !memcmp(fdc->packet_tx + 6, fdc->tx_header, 6);
|
|
*bcast_bit = !memcmp(fdc->packet_tx, fdc_header_bcast, 6);
|
|
|
|
memcpy(tmp, fdc->packet_tx, 6);
|
|
memcpy(fdc->packet_tx, fdc->packet_tx + 6, 6);
|
|
memcpy(fdc->packet_tx + 6, tmp, 6);
|
|
|
|
crc = fdc_crc(fdc->packet_tx, fdc->packet_tx_size);
|
|
|
|
fdc->packet_tx[fdc->packet_tx_size] = crc & 0xff;
|
|
fdc->packet_tx_size++;
|
|
fdc->packet_tx[fdc->packet_tx_size] = (crc >> 8) & 0xff;
|
|
fdc->packet_tx_size++;
|
|
|
|
if (*from_bit) {
|
|
fdc->packet_tx_cnt = 6;
|
|
} else {
|
|
if (*bcast_bit) {
|
|
memcpy(fdc->packet_tx + 6, fdc->packet_tx, 6);
|
|
}
|
|
}
|
|
if (*bcast_bit) {
|
|
fdc->packet_tx_cnt += 6;
|
|
}
|
|
}
|
|
}
|
|
if (fdc->packet_tx_size) {
|
|
std::size_t copy = fdc->packet_tx_size - fdc->packet_tx_cnt;
|
|
|
|
if (copy > size) {
|
|
copy = size;
|
|
*end_bits = 0;
|
|
} else {
|
|
*end_bits = copy;
|
|
fdc->packet_tx_size = 0;
|
|
}
|
|
memcpy(data, fdc->packet_tx + fdc->packet_tx_cnt, copy);
|
|
fdc->packet_tx_cnt += copy;
|
|
}
|
|
}
|
|
|
|
void freedv_data_set_header(struct freedv_data_channel *fdc, unsigned char *header)
|
|
{
|
|
unsigned short crc = fdc_crc(header, 6);
|
|
|
|
memcpy(fdc->tx_header, header, 6);
|
|
fdc->tx_header[6] = crc & 0xff;
|
|
fdc->tx_header[7] = (crc >> 8) & 0xff;
|
|
}
|
|
|
|
int freedv_data_get_n_tx_frames(struct freedv_data_channel *fdc, std::size_t size)
|
|
{
|
|
if (fdc->packet_tx_size == 0)
|
|
return 0;
|
|
/* packet will be send in 'size' byte frames */
|
|
return (fdc->packet_tx_size - fdc->packet_tx_cnt + size-1) / size;
|
|
}
|
|
|
|
} // FreeDV
|