#pragma pack(4)
#pragma comment(lib, "ws2_32.lib")
#include   "winsock2.h"
#include   "stdlib.h"
#include   "stdio.h"
#define ICMP_ECHO 8
#define ICMP_ECHOREPLY 0
#define ICMP_MIN 8 // minimum 8 byte icmp packet (just header)

/* The IP header */
typedef struct iphdr {
 unsigned int h_len:4; // length of the header
 unsigned int version:4; // Version of IP
 unsigned char tos; // Type of service
 unsigned short total_len; // total length of the packet
 unsigned short ident; // unique identifier
 unsigned short frag_and_flags; // flags
 unsigned char ttl;
 unsigned char proto; // protocol (TCP, UDP etc)
 unsigned short checksum; // IP checksum
 unsigned int sourceIP;
 unsigned int destIP;
}IpHeader;

//
// ICMP header
//

typedef struct icmphdr {
 BYTE i_type;
 BYTE i_code; /* type sub code */
 USHORT i_cksum;
 USHORT i_id;
 USHORT i_seq;
 /* This is not the std header, but we reserve space for time */
 ULONG timestamp;
}IcmpHeader;

#define STATUS_FAILED 0xFFFF
#define DEF_PACKET_SIZE    32
#define DEF_PACKET_NUMBER  4    /* 傳送資料報的個數 */
#define MAX_PACKET 1024

#define xmalloc(s) HeapAlloc(GetProcessHeap(),HEAP_ZERO_MEMORY,(s))
#define xfree(p) HeapFree (GetProcessHeap(),0,(p))
void fill_icmp_data(char *, int);
USHORT checksum(USHORT *, int);
int decode_resp(char *,int ,struct sockaddr_in *);
void Usage(char *progname){
 fprintf(stderr,"Usage:/n");
 fprintf(stderr,"%s [number of packets] [data_size]/n",progname);
 fprintf(stderr,"datasize can be up to 1Kb/n");
 ExitProcess(STATUS_FAILED);
}

int main(int argc, char **argv){
 WSADATA wsaData;
 SOCKET sockRaw;
 struct sockaddr_in dest,from;
 struct hostent * hp;
 int bread,datasize,times;
 int fromlen = sizeof(from);
 int timeout = 1000;
 int statistic = 0;  /* 用於統計結果 */ 
 char *dest_ip;
 char *icmp_data;
 char *recvbuf;
 unsigned int addr=0;
 USHORT seq_no = 0;
 if (WSAStartup(MAKEWORD(2,1),&wsaData) != 0){
  fprintf(stderr,"WSAStartup failed: %d/n",GetLastError());
  ExitProcess(STATUS_FAILED);
 }
 if (argc <2 ) {
  Usage(argv[0]);
 }
 sockRaw = WSASocket(AF_INET,SOCK_RAW,IPPROTO_ICMP,NULL, 0,WSA_FLAG_OVERLAPPED);
 //
 //注：為了使用傳送接收超時設定(即設定SO_RCVTIMEO, SO_SNDTIMEO)，
 //    必須將標誌位設為WSA_FLAG_OVERLAPPED !
 //
 if (sockRaw == INVALID_SOCKET) {
  fprintf(stderr,"WSASocket() failed: %d/n",WSAGetLastError());
  ExitProcess(STATUS_FAILED);
 }
 bread = setsockopt(sockRaw,SOL_SOCKET,SO_RCVTIMEO,(char*)&timeout,
      sizeof(timeout));
 if(bread == SOCKET_ERROR) {
  fprintf(stderr,"failed to set recv timeout: %d/n",WSAGetLastError());
  ExitProcess(STATUS_FAILED);
 }
 timeout = 1000;
 bread = setsockopt(sockRaw,SOL_SOCKET,SO_SNDTIMEO,(char*)&timeout,
      sizeof(timeout));
 if(bread == SOCKET_ERROR) {
  fprintf(stderr,"failed to set send timeout: %d/n",WSAGetLastError());
  ExitProcess(STATUS_FAILED);
 }
 memset(&dest,0,sizeof(dest));
 hp = gethostbyname(argv[1]);
 if (!hp){
  addr = inet_addr(argv[1]);
 }
 if ((!hp) && (addr == INADDR_NONE) ) {
  fprintf(stderr,"Unable to resolve %s/n",argv[1]);
  ExitProcess(STATUS_FAILED);
 }
 if (hp != NULL)
  memcpy(&(dest.sin_addr),hp->h_addr,hp->h_length);
 else
  dest.sin_addr.s_addr = addr;

 if (hp)
  dest.sin_family = hp->h_addrtype;
 else
  dest.sin_family = AF_INET;

 dest_ip = inet_ntoa(dest.sin_addr);

 //
 //  atoi函式原型是: int atoi( const char *string );
 //  The return value is 0 if the input cannot be converted to an integer !
 //
 if(argc>2)
 {
  times=atoi(argv[2]);
  if(times == 0)
   times=DEF_PACKET_NUMBER;
 }
 else
  times=DEF_PACKET_NUMBER;

 if (argc >3)
 {
  datasize = atoi(argv[3]);
  if (datasize == 0)
   datasize = DEF_PACKET_SIZE;
  if (datasize >1024)   /* 使用者給出的資料包大小太大 */
  {
    fprintf(stderr,"WARNING : data_size is too large !/n");
    datasize = DEF_PACKET_SIZE;
  }
 }
 else
  datasize = DEF_PACKET_SIZE;

 datasize += sizeof(IcmpHeader);
 icmp_data = (char*)xmalloc(MAX_PACKET);
 recvbuf = (char*)xmalloc(MAX_PACKET);
 if (!icmp_data) {
  fprintf(stderr,"HeapAlloc failed %d/n",GetLastError());
  ExitProcess(STATUS_FAILED);
 }

 memset(icmp_data,0,MAX_PACKET);
 fill_icmp_data(icmp_data,datasize);
 //
 //顯示提示資訊
 //
 fprintf(stdout,"/nPinging %s ..../n/n",dest_ip);

 for(int i=0; i<times; i++){                       //改正部分
  int bwrote;
  ((IcmpHeader*)icmp_data)->i_cksum = 0;
  ((IcmpHeader*)icmp_data)->timestamp = GetTickCount();
  ((IcmpHeader*)icmp_data)->i_seq = seq_no++;
  ((IcmpHeader*)icmp_data)->i_cksum = checksum((USHORT*)icmp_data,datasize);
  bwrote = sendto(sockRaw,icmp_data,datasize,0,(struct sockaddr*)&dest,sizeof(dest));
  if (bwrote == SOCKET_ERROR){
   if (WSAGetLastError() == WSAETIMEDOUT) {
    printf("Request timed out./n");
    continue;
   }
   fprintf(stderr,"sendto failed: %d/n",WSAGetLastError());
   ExitProcess(STATUS_FAILED);
  }
  if (bwrote < datasize ) {
   fprintf(stdout,"Wrote %d bytes/n",bwrote);
  }
  
  bread = recvfrom(sockRaw,recvbuf,MAX_PACKET,0,(struct sockaddr*)&from,&fromlen);
  if (bread == SOCKET_ERROR){
   if (WSAGetLastError() == WSAETIMEDOUT) {
    printf("Request timed out./n");
    continue;
   }
   fprintf(stderr,"recvfrom failed: %d/n",WSAGetLastError());
   ExitProcess(STATUS_FAILED);
  }
  if(!decode_resp(recvbuf,bread,&from))
   statistic++; /* 成功接收的數目++ */
  Sleep(1000);
 }

 /*
 Display the statistic result
 */
 fprintf(stdout,"/nPing statistics for %s /n",dest_ip);
 fprintf(stdout,"    Packets: Sent = %d,Received = %d, Lost = %d (%2.0f%% loss)/n",times,
   statistic,(times-statistic),(float)(times-statistic)/times*100);

 WSACleanup();
 return 0;
}

/*
The response is an IP packet. We must decode the IP header to locate
the ICMP data
*/
int decode_resp(char *buf, int bytes,struct sockaddr_in *from) {
 IpHeader *iphdr;
 IcmpHeader *icmphdr;
 unsigned short iphdrlen;
 iphdr = (IpHeader *)buf;
 iphdrlen = (iphdr->h_len) * 4 ; // number of 32-bit words *4 = bytes
 if (bytes < iphdrlen + ICMP_MIN) {
  printf("Too few bytes from %s/n",inet_ntoa(from->sin_addr));
 }
 icmphdr = (IcmpHeader*)(buf + iphdrlen);
 if (icmphdr->i_type != ICMP_ECHOREPLY) {
  fprintf(stderr,"non-echo type %d recvd/n",icmphdr->i_type);
  return 1;
 }
 if (icmphdr->i_id != (USHORT)GetCurrentProcessId()) {
  fprintf(stderr,"someone else''s packet!/n");
  return 1;
 }
 printf("%d bytes from %s:",bytes, inet_ntoa(from->sin_addr));
 printf(" icmp_seq = %d. ",icmphdr->i_seq);
 printf(" time: %d ms ",GetTickCount()-icmphdr->timestamp);
 printf("/n");
 return 0;
 }

 USHORT checksum(USHORT *buffer, int size) {
 unsigned long cksum=0;
 while(size >1) {
  cksum+=*buffer++;
  size -=sizeof(USHORT);
 }
 if(size) {
  cksum += *(UCHAR*)buffer;
 }
 cksum = (cksum >> 16) + (cksum & 0xffff);
 cksum += (cksum >>16);
 return (USHORT)(~cksum);
}
 

/*
Helper function to fill in various stuff in our ICMP request.
*/
void fill_icmp_data(char * icmp_data, int datasize){
 IcmpHeader *icmp_hdr;
 char *datapart;
 icmp_hdr = (IcmpHeader*)icmp_data;
 icmp_hdr->i_type = ICMP_ECHO;
 icmp_hdr->i_code = 0;
 icmp_hdr->i_id = (USHORT)GetCurrentProcessId();
 icmp_hdr->i_cksum = 0;
 icmp_hdr->i_seq = 0;
 datapart = icmp_data + sizeof(IcmpHeader);

 //
 // Place some junk in the buffer.
 //
 memset(datapart,'E', datasize - sizeof(IcmpHeader));   //改正部分
}