void build_packet(unsigned char *buf, unsigned short len)
{
    unsigned int i;
    unsigned int sum;
    unsigned char tmp;
    unsigned char tmp1;
    unsigned char tmp2;
    unsigned char tmp3;
    unsigned char tmp4;
    unsigned char tmp5;
    unsigned char tmp6;
    unsigned char packet[64];

    sum = 0x0;
    i = 0x6;

    /* 38 is 32 + 6 we count 32 starting from 6 */
    while (i <= 38) {
        sum += buf[i];

        i += 1;
    }

    buf[0] = 0x12;
    buf[1] = 0xc5;

    buf[5] = 0x20;

    return;
}