flipperzero-firmware/applications/nfc/helpers/nfc_debug_pcap.c

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C
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#include "nfc_debug_pcap.h"
#include <furi_hal_rtc.h>
#include <stream_buffer.h>
#define TAG "NfcDebugPcap"
#define PCAP_MAGIC 0xa1b2c3d4
#define PCAP_MAJOR 2
#define PCAP_MINOR 4
#define DLT_ISO_14443 264
#define DATA_PICC_TO_PCD 0xFF
#define DATA_PCD_TO_PICC 0xFE
#define DATA_PICC_TO_PCD_CRC_DROPPED 0xFB
#define DATA_PCD_TO_PICC_CRC_DROPPED 0xFA
#define NFC_DEBUG_PCAP_FILENAME "/ext/nfc/debug.pcap"
#define NFC_DEBUG_PCAP_BUFFER_SIZE 64
struct NfcDebugPcapWorker {
bool alive;
Storage* storage;
File* file;
StreamBufferHandle_t stream;
FuriThread* thread;
};
static File* nfc_debug_pcap_open(Storage* storage) {
File* file = storage_file_alloc(storage);
if(!storage_file_open(file, NFC_DEBUG_PCAP_FILENAME, FSAM_WRITE, FSOM_OPEN_APPEND)) {
storage_file_free(file);
return NULL;
}
if(!storage_file_tell(file)) {
struct {
uint32_t magic;
uint16_t major, minor;
uint32_t reserved[2];
uint32_t snaplen;
uint32_t link_type;
} __attribute__((__packed__)) pcap_hdr = {
.magic = PCAP_MAGIC,
.major = PCAP_MAJOR,
.minor = PCAP_MINOR,
.snaplen = FURI_HAL_NFC_DATA_BUFF_SIZE,
.link_type = DLT_ISO_14443,
};
if(storage_file_write(file, &pcap_hdr, sizeof(pcap_hdr)) != sizeof(pcap_hdr)) {
FURI_LOG_E(TAG, "Failed to write pcap header");
}
}
return file;
}
static void
nfc_debug_pcap_write(NfcDebugPcapWorker* instance, uint8_t event, uint8_t* data, uint16_t len) {
FuriHalRtcDateTime datetime;
furi_hal_rtc_get_datetime(&datetime);
struct {
// https://wiki.wireshark.org/Development/LibpcapFileFormat#record-packet-header
uint32_t ts_sec;
uint32_t ts_usec;
uint32_t incl_len;
uint32_t orig_len;
// https://www.kaiser.cx/posts/pcap-iso14443/#_packet_data
uint8_t version;
uint8_t event;
uint16_t len;
} __attribute__((__packed__)) pkt_hdr = {
.ts_sec = furi_hal_rtc_datetime_to_timestamp(&datetime),
.ts_usec = 0,
.incl_len = len + 4,
.orig_len = len + 4,
.version = 0,
.event = event,
.len = len << 8 | len >> 8,
};
xStreamBufferSend(instance->stream, &pkt_hdr, sizeof(pkt_hdr), osWaitForever);
xStreamBufferSend(instance->stream, data, len, osWaitForever);
}
static void
nfc_debug_pcap_write_tx(uint8_t* data, uint16_t bits, bool crc_dropped, void* context) {
NfcDebugPcapWorker* instance = context;
uint8_t event = crc_dropped ? DATA_PCD_TO_PICC_CRC_DROPPED : DATA_PCD_TO_PICC;
nfc_debug_pcap_write(instance, event, data, bits / 8);
}
static void
nfc_debug_pcap_write_rx(uint8_t* data, uint16_t bits, bool crc_dropped, void* context) {
NfcDebugPcapWorker* instance = context;
uint8_t event = crc_dropped ? DATA_PICC_TO_PCD_CRC_DROPPED : DATA_PICC_TO_PCD;
nfc_debug_pcap_write(instance, event, data, bits / 8);
}
int32_t nfc_debug_pcap_thread(void* context) {
NfcDebugPcapWorker* instance = context;
uint8_t buffer[NFC_DEBUG_PCAP_BUFFER_SIZE];
while(instance->alive) {
size_t ret =
xStreamBufferReceive(instance->stream, buffer, NFC_DEBUG_PCAP_BUFFER_SIZE, 50);
if(storage_file_write(instance->file, buffer, ret) != ret) {
FURI_LOG_E(TAG, "Failed to write pcap data");
}
}
return 0;
}
NfcDebugPcapWorker* nfc_debug_pcap_alloc(Storage* storage) {
NfcDebugPcapWorker* instance = malloc(sizeof(NfcDebugPcapWorker));
instance->alive = true;
instance->storage = storage;
instance->file = nfc_debug_pcap_open(storage);
instance->stream = xStreamBufferCreate(4096, 1);
instance->thread = furi_thread_alloc();
furi_thread_set_name(instance->thread, "PcapWorker");
furi_thread_set_stack_size(instance->thread, 1024);
furi_thread_set_callback(instance->thread, nfc_debug_pcap_thread);
furi_thread_set_context(instance->thread, instance);
furi_thread_start(instance->thread);
return instance;
}
void nfc_debug_pcap_free(NfcDebugPcapWorker* instance) {
furi_assert(instance);
instance->alive = false;
furi_thread_join(instance->thread);
furi_thread_free(instance->thread);
vStreamBufferDelete(instance->stream);
if(instance->file) storage_file_free(instance->file);
instance->storage = NULL;
free(instance);
}
void nfc_debug_pcap_prepare_tx_rx(
NfcDebugPcapWorker* instance,
FuriHalNfcTxRxContext* tx_rx,
bool is_picc) {
if(!instance || !instance->file) return;
if(is_picc) {
tx_rx->sniff_tx = nfc_debug_pcap_write_rx;
tx_rx->sniff_rx = nfc_debug_pcap_write_tx;
} else {
tx_rx->sniff_tx = nfc_debug_pcap_write_tx;
tx_rx->sniff_rx = nfc_debug_pcap_write_rx;
}
tx_rx->sniff_context = instance;
}