crashtest-r0ket/firmware/funk/openbeacon.c

#include <stdint.h>
#include "funk/openbeacon.h"
#include "funk/nrf24l01p.h"
#include "basic/byteorder.h"
#include "sysdefs.h"
#include "filesystem/ff.h"
#include "basic/uuid.h"

//const uint32_t key[4] = {0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF};
const uint32_t openbeaconkey[4] = { 0xB4595344,0xD3E119B6,0xA814D0EC,0xEFF5A24E };
const uint8_t useencryption = 1;
const uint8_t mac[5] = {1,2,3,2,1};

volatile uint32_t oid = 0;
volatile uint32_t seq = 0;
volatile uint8_t strength = 0;

void openbeaconShutdown(void)
{    
    openbeaconSave(seq);
}

void openbeaconSaveBlock(void)
{

    openbeaconSave(seq + OPENBEACON_SAVE + 1);
}

void openbeaconSave(uint32_t s)
{
    FIL file;
    BYTE buf[4];
    UINT readbytes;

    if( f_open(&file, "beacon", FA_OPEN_ALWAYS|FA_WRITE) )
        return;

    uint32touint8p(s, buf);

    if( f_write(&file, buf, 4, &readbytes) )
        return; 

    f_close(&file);
}

void openbeaconRead()
{
    FIL file;
    BYTE buf[4];
    UINT readbytes;

    if( f_open(&file, "beacon.cfg", FA_OPEN_EXISTING|FA_READ) )
        return;

    if( f_read(&file, buf, 4, &readbytes) )
        return;
    seq = uint8ptouint32(buf);
    
    f_close(&file);
}


void openbeaconSetup(void)
{
    oid = GetUUID32();
    strength = 0;
    openbeaconRead();
    openbeaconSaveBlock();
}

uint8_t openbeaconSendPacket(uint32_t id, uint32_t seq,
        uint8_t flags, uint8_t strength)
{
    uint8_t buf[32];

    buf[0]=0x10; // Length: 16 bytes
    buf[1]=0x17; // Proto - fixed at 0x17?
    buf[2]=flags;
    buf[3]=strength*85; // Send intensity

    uint32touint8p(seq, buf+4);
    uint32touint8p(id, buf+8);

    buf[12]=0xff; // salt (0xffff always?)
    buf[13]=0xff;

    return nrf_snd_pkt_crc_encr(16,buf,useencryption?openbeaconkey:NULL);
}

uint8_t openbeaconSend(void)
{
    uint8_t status;
    nrf_set_strength(strength);
    nrf_set_tx_mac(sizeof(mac), mac);

    status = openbeaconSendPacket(oid, seq, 0xFF, strength++);
    if( strength == 4 )
        strength = 0;
    if( seq++ & OPENBEACON_SAVE == OPENBEACON_SAVE )
        openbeaconSaveBlock();
    return status;
}