packet_interface.c

#include "packet_interface.h"

#include <arpa/inet.h>
#include <zlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>

/*************** Structures definition ***************/
struct __attribute__((__packed__)) pkt {
    header_t header;
    uint8_t payload[512];
};

typedef uint8_t header_t[32];

/************* Functions definition *************/
pkt_t* pkt_new()
{
    pkt_t * toReturn = (pkt_t *) malloc(sizeof(pkt_t));
    return  toReturn;
}

void pkt_del(pkt_t *pkt)
{
    free(pkt);
}

/**
 * @brief Calculates the CRC32
 * 
 * @param buffer    : The buffer on which to calculate CRC32.
 * @param len       : The number of bytes of the buffer.
 * @return uint32_t 
 */
uint32_t calculate_crc(char * buffer, uint32_t len)
{
    return (uint32_t) crc32(0, (const void *) buffer, len);
}

pkt_status_code pkt_decode_data_fec(const char *data, const size_t len, pkt_t *pkt)
{
    
}

pkt_status_code pkt_decode_ack_nack(const char *data, const size_t len, pkt_t *pkt)
{
    if (len < 8)
        return E_NOHEADER;
    
    // REMINDER : *data will read the first byte
    ptypes_t type = ((*data) & 0xC0) >> 6; 
    if ( type != PTYPE_ACK && type != PTYPE_NACK )
        return E_TYPE;

    if ( ((*data) & 0x20) != 0)
        return E_TR;
    
    uint8_t seqnum, window;
    memcpy((char *) &seqnum, data+1, 1);
    memcpy((char *) &window, data, 1);
    window = window & 0x1F;
    if (seqnum > window)
        return E_SEQNUM;

    // CheckSum no need to set TR at 0 as it should be at 0
    char crc[4];
    memcpy(crc, data+4, 4);
    if (calculate_crc(data, 4) != ntohl((uint32_t) crc))
        return E_CRC;    
}

pkt_status_code pkt_decode(const char *data, const size_t len, pkt_t *pkt)
{
    int is_ack_nack = len <= 8; // Maximum ACK or NACK size is 12 bytes
    if (is_ack_nack)
        return pkt_decode_ack_nack(data, len, pkt);
    else
        return pkt_decode_data_fec(data, len, pkt);
}

pkt_status_code pkt_encode(const pkt_t* pkt, char *buf, size_t *len)
{
    /* Your code will be inserted here */
}

ptypes_t pkt_get_type  (const pkt_t* pkt)
{
    /* Your code will be inserted here */
}

uint8_t  pkt_get_tr(const pkt_t* pkt)
{
    /* Your code will be inserted here */
}

uint8_t  pkt_get_window(const pkt_t* pkt)
{
    /* Your code will be inserted here */
}

uint8_t  pkt_get_seqnum(const pkt_t* pkt)
{
    /* Your code will be inserted here */
}

uint16_t pkt_get_length(const pkt_t* pkt)
{
    /* Your code will be inserted here */
}

uint32_t pkt_get_timestamp   (const pkt_t* pkt)
{
    /* Your code will be inserted here */
}

uint32_t pkt_get_crc1   (const pkt_t* pkt)
{
    /* Your code will be inserted here */
}

uint32_t pkt_get_crc2   (const pkt_t* pkt)
{
    /* Your code will be inserted here */
}

const char* pkt_get_payload(const pkt_t* pkt)
{
    /* Your code will be inserted here */
}


pkt_status_code pkt_set_type(pkt_t *pkt, const ptypes_t type)
{
    /* Your code will be inserted here */
}

pkt_status_code pkt_set_tr(pkt_t *pkt, const uint8_t tr)
{
    /* Your code will be inserted here */
}

pkt_status_code pkt_set_window(pkt_t *pkt, const uint8_t window)
{
    /* Your code will be inserted here */
}

pkt_status_code pkt_set_seqnum(pkt_t *pkt, const uint8_t seqnum)
{
    /* Your code will be inserted here */
}

pkt_status_code pkt_set_length(pkt_t *pkt, const uint16_t length)
{
    /* Your code will be inserted here */
}

pkt_status_code pkt_set_timestamp(pkt_t *pkt, const uint32_t timestamp)
{
    /* Your code will be inserted here */
}

pkt_status_code pkt_set_crc1(pkt_t *pkt, const uint32_t crc1)
{
    /* Your code will be inserted here */
}

pkt_status_code pkt_set_crc2(pkt_t *pkt, const uint32_t crc2)
{
    /* Your code will be inserted here */
}

pkt_status_code pkt_set_payload(pkt_t *pkt,
                                const char *data,
                                const uint16_t length)
{
    /* Your code will be inserted here */
}


ssize_t varuint_decode(const uint8_t *data, const size_t len, uint16_t *retval)
{
    /* Your code will be inserted here */
}


ssize_t varuint_encode(uint16_t val, uint8_t *data, const size_t len)
{
    /* Your code will be inserted here */
}

size_t varuint_len(const uint8_t *data)
{
    /* Your code will be inserted here */
}


ssize_t varuint_predict_len(uint16_t val)
{
    /* Your code will be inserted here */
}


ssize_t predict_header_length(const pkt_t *pkt)
{
    /* Your code will be inserted here */
}