#include <sys/socket.h>
#include <linux/if_packet.h>
#include <linux/if_ether.h>
#include <linux/if_arp.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <netinet/in.h>
#include <ctype.h>
//#define ETH_FRAME_LEN 1518
// 14 + 46-1500 + 4
#define ETH_FRAME_LEN 60
char *trimwhitespace(char *str)
{
  char *end;

  // Trim leading space
  while(isspace(*str)) str++;

  if(*str == 0)  // All spaces?
    return str;

  // Trim trailing space
  end = str + strlen(str) - 1;
  while(end > str && isspace(*end)) end--;

  // Write new null terminator
  *(end+1) = 0;

  return str;
}
char *replace_str(char *str, char *orig, char *rep)
{
  static char buffer[4096];
  char *p;

  if(!(p = strstr(str, orig)))  // Is 'orig' even in 'str'?
    return str;

  strncpy(buffer, str, p-str); // Copy characters from 'str' start to 'orig' st$
  buffer[p-str] = '\0';

  sprintf(buffer+(p-str), "%s%s", rep, p+strlen(orig));

  return buffer;
}
int main()
{
int s; /*socketdescriptor*/

s = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
if (s == -1) { printf("socket error"); }

/*target address*/
struct sockaddr_ll socket_address;

/*buffer for ethernet frame*/
unsigned char* buffer = (unsigned char*)malloc(ETH_FRAME_LEN);

/*pointer to ethenet header*/
unsigned char* etherhead = (unsigned char*)buffer;
	
/*userdata in ethernet frame*/
unsigned char* data = (unsigned char*)(buffer);
	
/*another pointer to ethernet header*/
struct ethhdr *eh = (struct ethhdr *)etherhead;
 
int send_result = 0;

/*our MAC address*/
unsigned char src_mac[6] = {0x10, 0x78, 0xd2, 0xad, 0x90, 0xcb};

/*other host MAC address 10:78:d2:ad:90:cb*/
unsigned char dest_mac[6] = {0x10, 0x78, 0xd2, 0xad, 0x90, 0xcb};

/*prepare sockaddr_ll*/

/*RAW communication*/
socket_address.sll_family   = PF_PACKET;	
/*we don't use a protocoll above ethernet layer
  ->just use anything here*/
socket_address.sll_protocol = htons(ETH_P_IP);	

/*index of the network device
see full code later how to retrieve it*/
socket_address.sll_ifindex  = 2;

/*ARP hardware identifier is ethernet*/
socket_address.sll_hatype   = ARPHRD_ETHER;
	
/*target is another host*/
socket_address.sll_pkttype  = PACKET_OTHERHOST;

/*address length*/
socket_address.sll_halen    = ETH_ALEN;		
/*MAC - begin*/
socket_address.sll_addr[0]  = 0x10;		
socket_address.sll_addr[1]  = 0x78;		
socket_address.sll_addr[2]  = 0xd2;
socket_address.sll_addr[3]  = 0xad;
socket_address.sll_addr[4]  = 0x90;
socket_address.sll_addr[5]  = 0xcb;
/*MAC - end*/
socket_address.sll_addr[6]  = 0x00;/*not used*/
socket_address.sll_addr[7]  = 0x00;/*not used*/

int length=0;
int succeed = 0;
int i =0;
int j = 0;
while(true)
{
	length = recvfrom(s, buffer, ETH_FRAME_LEN, 0, NULL, NULL);

	if (length == -1 && succeed == 0) {
		printf("recv error\n");
		succeed = 2;
	}
	if(length > 0)
	{
		char buff[46] = "\0";
		memcpy(&buff, &buffer[14], 46);
		printf(trimwhitespace(buff));
	}
}
}