#include<stdio.h>

#include<stdlib.h>

#include<string.h>

#include<math.h>

#include<netdb.h>
#include<unistd.h>
#include<sys/time.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in_systm.h>
#include<netinet/in.h>
#include<netinet/ip.h>
#include<netinet/ip_icmp.h>
#include<arpa/inet.h>
#include <time.h>


/*#define CHKADDRESS( _saddr_)
{
   u_char *p =(char *)&(_saddr_);
   if( (p[0] == 10) || (p[0] ==168 &&16<=p[1]&&p[1]<=31) ||(p[0] ==192 && p[1]==168)
   {}
   else
   {

    fprintf(stderr,"IP address error.\n");
    exit(EXIT_FAILURE);
   }
}*/

enum {CMD_NAME,DST_IP,START_PORT,LAST_PORT};

#define MAXBUFF 8192

int main(int argc,char *argv[])
{
  clock_t start, finish;  
  struct icmp *icmp;
  fd_set select_fd;
  struct sockaddr_in send_sa;
  int recv_sd;
  int send_sd;
  char buff[MAXBUFF];
  int endport;
  int startport;
  int dstport;
  struct timeval tv;
  struct ip *ip;
  int hlen,port;
  int count;

  if(argc!=4)
  {
    fprintf(stderr," usge:%s dst_ip start_port last_port\n",argv[CMD_NAME]);
    exit(EXIT_FAILURE);
  }
  send_sa.sin_family = AF_INET;
  send_sa.sin_addr.s_addr = inet_addr(argv[DST_IP]);

  startport = atoi(argv[START_PORT]);
  endport = atoi(argv[LAST_PORT]);
  //CHKADDRESS(send_sa.sin_addr.s_addr);
  
  if( (send_sd = socket(AF_INET,SOCK_DGRAM,0))<0)
  {
    perror(" socket (SOCK_DGRAM)");
    exit(EXIT_FAILURE);
  }

  if( (recv_sd = socket(AF_INET,SOCK_RAW,IPPROTO_ICMP))<0)
  {
    perror(" socket (SOCK_RAW)");
    exit(EXIT_FAILURE);
  }

  for(dstport = startport;dstport<=endport;dstport++)
  {
    printf(" Scan port %d: %d times\r",dstport,count);
        fflush(stdout);
      send_sa.sin_port = htons (dstport);
    sendto(send_sd,NULL,0,0,(void *) &send_sa,sizeof(send_sa));
       
    tv.tv_sec=1;
    tv.tv_usec=0;
    count=0;                   //记录每次同一端口,ICMP包数量
    start = clock();  

    while(1)
    {
        FD_ZERO(&select_fd);
        FD_SET(recv_sd,&select_fd);
    
        if(select (recv_sd+1,&select_fd,NULL,NULL,&tv)>0) 
            if(recvfrom(recv_sd,buff,MAXBUFF,0,NULL,NULL)!=56)          //ICMP包,长度为56,IP+ICMP+IP+UDP
                continue;
            //intf("a new icmp ack\n");
            if( ((finish=clock() )-start)>=2)
            {
                printf("2 sec no target icmp ack.\n");
                struct servent *se_t;
                se_t=getservbyport(htons (dstport)," udp");
                printf("%5d %-20s\n",dstport,(se_t==NULL)?"unkown":se_t->s_name);
                break;
            }
            ip=(struct ip *)buff;
            hlen=ip->ip_hl<<2;
            icmp=(struct icmp *)(buff+hlen);

            port=ntohs(* (u_short *)(buff+20+8+20+2) );
            if( (ip->ip_src.s_addr!=send_sa.sin_addr.s_addr) || (icmp->icmp_type!=ICMP_UNREACH) || (icmp->icmp_code!=ICMP_UNREACH_PORT) ||(port!=dstport))
            {
                if(count>10)
                {
                    printf("port %d:icmp_type is %d;icmp_code is %d.\n",port,icmp->icmp_type,icmp->icmp_code);
                    break;
                }
                if(ip->ip_src.s_addr==send_sa.sin_addr.s_addr && port==dstport)
                {
                    //printf(" %d times\r",count);
                    count++;
                    break;
                }