Integrate TUN device interface
Packets are now read from the TUN device and transmitted. The signal goes through a channel emulator and is then received + decoded. If decoding is successful, the result is written back to the TUN device (which does not make much sense, but works for testing). Unfortunately, there still seems to be a problem in the receiver: packet loss is very high even at extremely high SNRs.
This commit is contained in:
parent
890baf577f
commit
934b18e382
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@ -31,6 +31,8 @@ set(sources
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src/layer1/whitening.h
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src/layer1/modcod.c
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src/layer1/modcod.h
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src/layer2/tundev.c
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src/layer2/tundev.h
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)
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include_directories(
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@ -51,6 +53,7 @@ target_link_libraries(
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m
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fftw3f
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fec
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SoapySDR
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)
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add_subdirectory(test)
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@ -3,8 +3,28 @@
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#include <liquid/liquid.h>
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/*** SDR CONFIG ***/
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#define SDR_IS_FULL_DUPLEX 0
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#define SDR_RX_SAMPLING_RATE 1e6f
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#define SDR_TX_SAMPLING_RATE RX_SAMPLING_RATE
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// actually transmitted or received signal frequencies, NOT the SDR center frequency.
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#define SDR_TX_FREQ 434.100e6f
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#define SDR_RX_FREQ 434.100e6f
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// shift applied in the baseband, to get rid of SDR DC peak. If the value here
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// is not 0, software mixing will be done on the received signal.
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#define SDR_TX_IF_SHIFT 0.000e6f
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#define SDR_RX_IF_SHIFT 0.150e6f
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// NOTE: the SDR center frequency will be SDR_RX_FREQ - SDR_RX_IF_SHIFT.
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/*** LAYER 1 CONFIG ***/
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#define SYMBOL_RATE 100e3f
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#define PAYLOAD_CHANNEL_CODE LIQUID_FEC_CONV_V27P34
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#define PAYLOAD_MODULATION LIQUID_MODEM_QAM16
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@ -27,27 +27,7 @@ result_t packet_mod_init(packet_mod_ctx_t *ctx)
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result_t packet_mod_free(packet_mod_ctx_t *ctx)
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{
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switch(ctx->state) {
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case DATA_RAW:
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case DATA_CODED:
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free(ctx->pkt_bytes);
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ctx->pkt_bytes = NULL;
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break;
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case DATA_MODULATED:
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case HEADER_ADDED:
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case PREAMBLE_ADDED:
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free(ctx->pkt_symbols);
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ctx->pkt_symbols = NULL;
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break;
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case NOT_STARTED:
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// nothing to do
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break;
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}
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ctx->state = NOT_STARTED;
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ctx->length = 0;
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packet_mod_reset(ctx); // frees all malloc'd memory
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fec_destroy(ctx->hdr_fec);
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modem_destroy(ctx->hdr_modem);
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@ -68,6 +48,25 @@ result_t packet_mod_set_modcod(packet_mod_ctx_t *ctx, modcod_t modcod)
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}
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result_t packet_mod_reset(packet_mod_ctx_t *ctx)
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{
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ctx->state = NOT_STARTED;
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ctx->length = 0;
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if(ctx->pkt_bytes) {
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free(ctx->pkt_bytes);
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ctx->pkt_bytes = NULL;
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}
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if(ctx->pkt_symbols) {
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free(ctx->pkt_symbols);
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ctx->pkt_symbols = NULL;
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}
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return OK;
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}
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result_t packet_mod_set_data(packet_mod_ctx_t *ctx, const unsigned char *data, size_t length)
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{
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if(ctx->state != NOT_STARTED) {
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@ -63,6 +63,15 @@ result_t packet_mod_free(packet_mod_ctx_t *ctx);
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*/
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result_t packet_mod_set_modcod(packet_mod_ctx_t *ctx, modcod_t modcod);
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/*!\brief Clears all data from the modulator.
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*
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* After this call, the packet modulator can accept a new packet. Configuration (e.g. modulation type) is not changed.
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*
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* \param[inout] ctx The context to use for this operation.
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* \returns An result code (see results.h).
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*/
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result_t packet_mod_reset(packet_mod_ctx_t *ctx);
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/*!\brief Set the raw packet data.
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*
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* In this step, the CRC of the data is calculated.
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@ -16,7 +16,7 @@
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#define AGC_BW_ACQUISITION 2e-2
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#define AGC_BW_TRACKING 1e-4
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#define SHOW_DEBUG_LOG 1
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#define SHOW_DEBUG_LOG 0
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#if SHOW_DEBUG_LOG
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# define DEBUG_LOG(...) fprintf(stderr, __VA_ARGS__)
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@ -74,7 +74,8 @@ result_t layer1_tx_reset(layer1_tx_t *tx)
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result_t layer1_tx_add_packet_to_burst(layer1_tx_t *tx, const uint8_t *data, size_t length)
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{
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if(tx->samples_used == 0) {
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if(!resize_buffer(tx, 4096 + transmission_calculate_ramp_up_length(&tx->transmission))) {
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if((tx->samples_allocated == 0)
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&& !resize_buffer(tx, 4096 + transmission_calculate_ramp_up_length(&tx->transmission))) {
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return ERR_NO_MEM;
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}
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@ -91,11 +92,12 @@ result_t layer1_tx_add_packet_to_burst(layer1_tx_t *tx, const uint8_t *data, siz
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}
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// encode and modulate the packet
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packet_mod_set_data(&tx->pmod, data, length);
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packet_mod_encode(&tx->pmod);
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packet_mod_modulate(&tx->pmod);
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packet_mod_add_header(&tx->pmod);
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packet_mod_add_preamble(&tx->pmod);
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ERR_CHECK(packet_mod_reset(&tx->pmod));
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ERR_CHECK(packet_mod_set_data(&tx->pmod, data, length));
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ERR_CHECK(packet_mod_encode(&tx->pmod));
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ERR_CHECK(packet_mod_modulate(&tx->pmod));
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ERR_CHECK(packet_mod_add_header(&tx->pmod));
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ERR_CHECK(packet_mod_add_preamble(&tx->pmod));
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// determine number of symbols in the packet
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size_t nsyms;
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84
impl/src/layer2/tundev.c
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84
impl/src/layer2/tundev.c
Normal file
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@ -0,0 +1,84 @@
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#include <linux/if.h>
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#include <linux/if_tun.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/ioctl.h>
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#include <stdio.h>
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#include <string.h>
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#include "tundev.h"
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int tundev_open(char *dev)
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{
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int tunfd = open("/dev/net/tun", O_RDWR);
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if(tunfd < 0) {
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perror("tundev: open");
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return -1;
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}
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struct ifreq ifr;
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memset(&ifr, 0, sizeof(ifr));
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ifr.ifr_flags = IFF_TUN | IFF_NO_PI;
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strncpy(ifr.ifr_name, dev, IFNAMSIZ);
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int ret = ioctl(tunfd, TUNSETIFF, &ifr);
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if(ret < 0) {
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perror("tundev: ioctl");
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goto error;
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}
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strcpy(dev, ifr.ifr_name);
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fprintf(stderr, "tundev: Successfully allocated tun device %s\n", dev);
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return tunfd;
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fprintf(stderr, "tundev: Closing device.\n");
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close(tunfd);
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return 0;
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error:
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close(tunfd);
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return -1;
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}
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result_t tundev_close(int tundev)
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{
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if(close(tundev) < 0) {
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return ERR_SYSCALL;
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} else {
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return OK;
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}
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}
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result_t tundev_read_loop(int tunfd, tundev_read_callback_t callback)
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{
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uint8_t buf[2048];
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int ret;
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do {
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ret = read(tunfd, buf, sizeof(buf));
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if(ret <= 0) {
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break;
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}
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fprintf(stderr, "tundev: Read %d bytes from tun device.\n", ret);
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} while(callback(buf, ret));
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if(ret == 0) {
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fprintf(stderr, "tundev: no more data.\n");
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return OK;
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} else {
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perror("tundev: read");
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return ERR_SYSCALL;
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}
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}
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17
impl/src/layer2/tundev.h
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17
impl/src/layer2/tundev.h
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@ -0,0 +1,17 @@
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#ifndef LAYER2_TUNDEV_H
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#define LAYER2_TUNDEV_H
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#include <stdbool.h>
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#include <stdint.h>
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#include <stddef.h>
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#include "results.h"
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typedef bool (*tundev_read_callback_t)(uint8_t *packet, size_t len);
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int tundev_open(char *dev);
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result_t tundev_close(int tundev);
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result_t tundev_read_loop(int tunfd, tundev_read_callback_t callback);
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#endif // LAYER2_TUNDEV_H
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@ -1,13 +1,18 @@
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#include <linux/if.h>
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#include <stdio.h>
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#include <string.h>
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#include <assert.h>
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#include <math.h>
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#include <liquid/liquid.h>
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#include <unistd.h>
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#include "utils.h"
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#include "layer1/tx.h"
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#include "layer1/rx.h"
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#include "layer2/tundev.h"
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#define RESULT_CHECK(stmt) { \
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result_t res = stmt; \
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if(res != OK) { \
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@ -16,6 +21,9 @@
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} \
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}
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static int m_tunfd = -1;
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static bool m_running = true;
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void print_complex_array(const char *varname, float complex const *array, size_t len)
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{
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fprintf(stderr, "%s=np.array([%f%+fj", varname, crealf(array[0]), cimagf(array[0]));
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@ -28,19 +36,26 @@ void print_complex_array(const char *varname, float complex const *array, size_t
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void cb_rx(rx_evt_t evt, uint8_t *packet_data, size_t packet_len)
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{
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int ret;
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switch(evt)
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{
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case RX_EVT_CHECKSUM_ERROR:
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fprintf(stderr, "Received a message of %zu bytes, but decoding failed.\n", packet_len);
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fprintf(stderr, "=== FAILED PAYLOAD ===\n");
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fprintf(stderr, "%s\n", packet_data);
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fprintf(stderr, "=======================\n");
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//fprintf(stderr, "=== FAILED PAYLOAD ===\n");
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//fprintf(stderr, "%s\n", packet_data);
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//fprintf(stderr, "=======================\n");
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break;
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case RX_EVT_PACKET_RECEIVED:
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fprintf(stderr, "=== DECODED PAYLOAD ===\n");
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fprintf(stderr, "=== DECODED PAYLOAD (%4zu bytes) ===\n", packet_len);
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fprintf(stderr, "%s\n", packet_data);
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fprintf(stderr, "=======================\n");
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fprintf(stderr, "====================================\n");
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ret = write(m_tunfd, packet_data, packet_len);
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if(ret < 0) {
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perror("write");
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}
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break;
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case RX_EVT_PREAMBLE_FOUND:
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@ -52,14 +67,49 @@ void cb_rx(rx_evt_t evt, uint8_t *packet_data, size_t packet_len)
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int main(void)
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{
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uint8_t msg_org[] = "Hello Liquid! This is the message to transmit. Hopefully it can be decoded correctly...";
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layer1_tx_t tx;
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layer1_rx_t rx;
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// ** Initialize **
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char devname[IFNAMSIZ] = "hamnet70";
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m_tunfd = tundev_open(devname);
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if(m_tunfd < 0) {
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return 1;
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}
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RESULT_CHECK(layer1_tx_init(&tx));
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RESULT_CHECK(layer1_rx_init(&rx, cb_rx));
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// channel emulation
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channel_cccf channel = channel_cccf_create();
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float snr = 15.0f;
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channel_cccf_add_awgn(channel, -snr, snr);
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channel_cccf_add_carrier_offset(channel, 0.20f, 1.00f);
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//channel_cccf_add_shadowing(channel, 1.00f, 0.1f);
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// ** Process packets **
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uint8_t packetbuf[2048];
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while(m_running) {
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int ret = read(m_tunfd, packetbuf, sizeof(packetbuf));
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if(ret < 0) {
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perror("read");
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break;
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} else if(ret == 0) {
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// no more data
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break;
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}
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fprintf(stderr, "Transmitting packet with %d bytes.\n", ret);
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RESULT_CHECK(layer1_tx_reset(&tx));
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// ** Modulate packet **
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layer1_tx_t tx;
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RESULT_CHECK(layer1_tx_init(&tx));
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RESULT_CHECK(layer1_tx_add_packet_to_burst(&tx, msg_org, sizeof(msg_org)));
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RESULT_CHECK(layer1_tx_add_packet_to_burst(&tx, packetbuf, ret));
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RESULT_CHECK(layer1_tx_finalize_burst(&tx));
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size_t burst_len = layer1_tx_get_sample_count(&tx);
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@ -69,18 +119,8 @@ int main(void)
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// ** Apply channel distortions **
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channel_cccf channel = channel_cccf_create();
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float snr = 10.0f;
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channel_cccf_add_awgn(channel, -snr, snr);
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channel_cccf_add_carrier_offset(channel, 0.20f, 1.00f);
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channel_cccf_add_shadowing(channel, 1.00f, 0.1f);
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// channel
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float complex msg_received[burst_len];
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//memcpy(msg_received, whole_burst, sizeof(whole_burst)); // no noise in channel
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channel_cccf_execute_block(channel, whole_burst, burst_len, msg_received);
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// scale the entire signal to give the AGC something to do
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@ -90,15 +130,12 @@ int main(void)
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dump_array_cf(msg_received, burst_len, 1.0f, "/tmp/rx.cpx");
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// ** RX starts here **
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layer1_rx_t rx;
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RESULT_CHECK(layer1_rx_init(&rx, cb_rx));
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// ** Receive signal **
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RESULT_CHECK(layer1_rx_process(&rx, msg_received, burst_len));
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}
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// cleanup
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// ** Cleanup **
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channel_cccf_destroy(channel);
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@ -15,9 +15,9 @@ typedef enum {
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# define ERR_CHECK_LIQUID(call) \
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do { \
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liquid_error_code result; \
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if((result = (call)) != LIQUID_OK) { \
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fprintf(stderr, "Liquid call failed in %s:%d: %s\n", __FILE__, __LINE__, liquid_error_info(result)); \
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liquid_error_code lq_result; \
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if((lq_result = (call)) != LIQUID_OK) { \
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fprintf(stderr, "Liquid call failed in %s:%d: %s\n", __FILE__, __LINE__, liquid_error_info(lq_result)); \
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return ERR_LIQUID; \
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} \
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} while(0);
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@ -25,4 +25,13 @@ typedef enum {
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# define ERR_CHECK_LIQUID(call) if((call) != LIQUID_OK) { return ERR_LIQUID; }
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#endif
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#define ERR_CHECK(call) \
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do { \
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result_t err_check_result = call; \
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if(err_check_result != OK) { \
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fprintf(stderr, "Error detected at %s:%d: %d\n", __FILE__, __LINE__, err_check_result); \
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return err_check_result; \
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} \
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} while(0);
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#endif // RESULTS_H
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