ntoh and hton implementation

byte_order.c

#include <string.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <netpacket/packet.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <net/if.h>
#include <netinet/in_systm.h>
#include <malloc.h>

uint16_t packet_ntohs(uint16_t network_short);
uint32_t packet_ntohl(uint32_t network_long);
uint16_t packet_htons(uint16_t host_short);
uint32_t packet_htonl(uint32_t host_long);


int main(int argc, char *argv[]){
        
    uint16_t a = 0x1234;
    uint32_t b = 0x12345678;

    printf("a = %x\n", a);
    printf("a to host byte order = %x\n", packet_ntohs(a));
    printf("b = %x\n", b);
    printf("b to host byte order = %x\n", packet_ntohl(b));

    uint16_t c = packet_ntohs(a);
    uint32_t d = packet_ntohl(b);

    printf("c = %x\n", c);
    printf("c to network byte order = %x\n", packet_htons(c));
    printf("d = %x\n", d);
    printf("d to network byte order = %x\n", packet_htonl(d));

return 0;
}

uint16_t packet_ntohs(uint16_t network_short){

    uint16_t tmp = 0;
    tmp = (network_short >> 0) & 0xff;
    tmp = tmp << 8;
    tmp |= (network_short >> 8) & 0xff;

    return tmp;
}

uint32_t packet_ntohl(uint32_t network_long){

    uint32_t tmp = 0;
    for(int i = 0; i < 4; i++){
    tmp |= (network_long >> i * 8) &0xff;
    if(i == 3) break;
    tmp = tmp << 8;
    }

    return tmp;    
}

uint16_t packet_htons(uint16_t host_short){
    uint16_t tmp = 0;
    tmp = (host_short << 0) & 0xff00;
    tmp = tmp >> 8;
    tmp |= (host_short << 8) & 0xff00;

    return tmp;
}
uint32_t packet_htonl(uint32_t host_long){

    uint32_t tmp = 0;
    for(int i = 0; i < 4; i++){
    tmp |= (host_long << i * 8) &0xff000000;
    if(i == 3) break;
    tmp = tmp >> 8;
    }

    return tmp;    
}