#include "tcp.h"
#include<sys/ioctl.h>
#include<net/if.h>
#define PROTO htons(ETH_P_ALL)

int main()
{
  //unsigned char packet[74];

  struct sockaddr_ll mysocket,to,from;
  int fromlen;
  struct tcphdr *tcp;
  int sockd, sd,on = 1;
  unsigned char rbuf[1500];
  int i,n;
  char errbuf[PCAP_ERRBUF_SIZE];
  pcap_t* descr;
  const u_char *packet;
  struct pcap_pkthdr hdr;     /* pcap.h */
  struct ether_header *eptr;  /* net/ethernet.h */
  u_char *ptr; /* printing out hardware header info */
  struct iphdr *ip;
  struct ifreq ifr;

  descr = pcap_open_offline("/root/s1.trace",errbuf);
    if(descr == NULL)
    {
        printf("pcap_open_offline(): %s\n",errbuf);
        exit(1);
    }
    packet = pcap_next(descr,&hdr);
    if(packet == NULL)
    {
        printf("Didn't grab packet\n");
        exit(1);
    }

   if((sockd = socket(PF_PACKET,SOCK_RAW,PROTO)) < 0)  
   {
     perror("socket");
     exit(1);
   }
 
  strncpy(ifr.ifr_name, "lo", sizeof(ifr.ifr_name));
  if (ioctl(sockd, SIOCGIFINDEX, &ifr) == -1)
   {
    fprintf(stderr, "SIOCGIFINDEX on %s failed: %s\n", "lo",strerror(errno));
    printf("my error\n");
    return 1;
   }
 

  memset(&mysocket,'\0',sizeof(mysocket));  
  mysocket.sll_family = AF_PACKET;
  mysocket.sll_protocol =htons(ETH_P_ALL); 
  mysocket.sll_ifindex  = ifr.ifr_ifindex;
    
  if (bind(sockd,(struct sockaddr *)&mysocket, sizeof(mysocket)) <0) 
    {
     perror("Bind");
     exit(1);
    }
    printf("Bind succecced \n");

  memset(&to , 0,sizeof(to));
  to.sll_family = AF_PACKET;
  to.sll_protocol =htons(ETH_P_ALL); 
  to.sll_ifindex  = ifr.ifr_ifindex;
  to.sll_halen = ETH_ALEN;
  memcpy(to.sll_addr,packet,ETH_ALEN);


 ip = (struct iphdr *) packet;  
 printf("Id1 %d\n",ip->ttl);
 ip->id=htons(getuid());
 printf("ID2 %d\n",(ip->id));
  n = sendto(sockd,packet,74,0x0,(struct sockaddr *)&to,sizeof(to));   
  if(n < 0)  
   {
    perror("sendto");
    exit(1);
    }
 else  printf("Packet send %d bytes \n",n);
  
  /* capture */
  printf("Now recev\n");
  
  
  bzero(rbuf,sizeof(rbuf));
  fromlen = sizeof(from);
  n = recvfrom(sockd,rbuf,sizeof(rbuf),0,(struct sockaddr *)&from,&fromlen);
 
   if(n < 0)  printf("ERROR\n");
    else printf("RECEived %dbytes\n",n);  
  
   printf("Packet type %d\n",from.sll_pkttype);
   printf("Packet hatype %d\n",from.sll_hatype);


    eptr = (struct ether_header *) rbuf;
    if (ntohs (eptr->ether_type) == ETHERTYPE_IP)
    {
        printf("Ethernet type hex:%x dec:%d is an IP packet\n",
                ntohs(eptr->ether_type),
                ntohs(eptr->ether_type));
    }
       else  if (ntohs (eptr->ether_type) == ETHERTYPE_ARP)
      {
        printf("Ethernet type hex:%x dec:%d is an ARP packet\n",
                ntohs(eptr->ether_type),
                ntohs(eptr->ether_type));
      }
      else 
       {
        printf("Ethernet type %x not IP", ntohs(eptr->ether_type));
        exit(1);
      }

   ip = (struct iphdr *)rbuf;
   printf("Version %d\n",ip->version);
   printf("Protocol %d\n",ip->protocol);
   //printf("Source IP: %s \t Destn IP: %s \n",inet_ntoa(ip->saddr) , inet_ntoa(ip->daddr));
   tcp  = (struct tcphdr *) rbuf;
   printf("Souce %04d and destn port %04d\n", ntohs(tcp->source), ntohs(tcp->dest));   
 
  exit(0);
}