这段代码什么意思,调试结果是什么,代码好像有点问题,怎么改啊?
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发布时间：2024-03-11 21:49
共1个回答
热心网友
时间：2024-07-28 22:53
* ping.c - Simple ping utility using SOCK_RAW
\********************************************************/
#define WIN32_LEAN_AND_MEAN
#include <winsock2.h>
#include <stdio.h>
#include <stdlib.h>
#define ICMP_ECHO 8 // 请求回显 ping请求 请求回显8
#define ICMP_ECHOREPLY 0 // 回显应答0
#define ICMP_MIN 12 // minimum 12 byte icmp packet (just header)
#pragma comment(lib,"Ws2_32.lib")
/* The IP header 20bytes*/
typedef struct iphdr {
unsigned char h_len:4; // length of the header
unsigned char 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 12 bytes */
typedef struct _ihdr {
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 MAX_PACKET 1024
#define xmalloc(s) HeapAlloc(GetProcessHeap(),HEAP_ZERO_MEMORY,(s))
#define xfree(p) HeapFree(GetProcessHeap(),0,(p))
USHORT checksum(USHORT *, int);
void fill_icmp_head(char *);
void decode_resp(char *,int ,struct sockaddr_in *);
void Usage(char *progname)
{
fprintf(stderr,"Usage:\n");
fprintf(stderr,"%s <host>\n",progname);
ExitProcess(STATUS_FAILED);
}
int main(int argc, char **argv)
{
WSADATA wsaData;
SOCKET sockRaw;
struct sockaddr_in dest,from;
struct hostent *hp;
int bread,datasize;
int fromlen = sizeof(from);
char *dest_ip;
char *icmp_data;
char *recvbuf;
unsigned int addr=0;
USHORT seq_no = 0;
if (WSAStartup(0x0101,&wsaData) != 0){
fprintf(stderr,"WSAStartup failed: %d\n",GetLastError());
ExitProcess(STATUS_FAILED);
}
if (argc <2 ) {
Usage(argv[0]);
}
if((sockRaw=socket(AF_INET,SOCK_RAW,IPPROTO_ICMP))==INVALID_SOCKET){
fprintf(stderr,"WSAStartup failed: %d\n",GetLastError());
ExitProcess(STATUS_FAILED);
}
memset(&dest,0,sizeof(dest));
hp = gethostbyname(argv[1]);
if (hp!=NULL){
memcpy(&(dest.sin_addr),hp->h_addr,hp->h_length);
dest.sin_family = AF_INET;
dest_ip = inet_ntoa(dest.sin_addr);
}
else{
fprintf(stderr,"Unable to resolve %s\n",argv[1]);
ExitProcess(STATUS_FAILED);
}
datasize=sizeof(IcmpHeader); // 12
icmp_data =(char*) xmalloc(MAX_PACKET); // 1024
recvbuf = (char *)xmalloc(MAX_PACKET); // 1024
if (!icmp_data) {
fprintf(stderr,"HeapAlloc failed %d\n",GetLastError());
ExitProcess(STATUS_FAILED);
}
memset(icmp_data,0,MAX_PACKET);
fill_icmp_head(icmp_data);
while(1) {
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, sizeof(IcmpHeader));
bwrote = sendto(sockRaw,icmp_data,datasize,0,(struct sockaddr*)&dest,sizeof(dest));
if (bwrote == SOCKET_ERROR){
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("timed out\n");
continue; }
fprintf(stderr,"recvfrom failed: %d\n",WSAGetLastError());
perror("revffrom failed.");
ExitProcess(STATUS_FAILED);
}
decode_resp(recvbuf,bread,&from);
Sleep(1000);
}
closesocket(sockRaw);
xfree(icmp_data);
xfree(recvbuf );
WSACleanup(); /* clean up ws2_32.dll */
return 0;
}
void fill_icmp_head(char * icmp_data){
IcmpHeader *icmp_hdr;
icmp_hdr = (IcmpHeader*)icmp_data;
icmp_hdr->i_type = ICMP_ECHO;
icmp_hdr->i_code = 0;
icmp_hdr->i_cksum = 0;
icmp_hdr->i_id = (USHORT)GetCurrentProcessId();
icmp_hdr->i_seq = 0;
}
/* The response is an IP packet. We must decode */
/* the IP header to locate the ICMP data */
void 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;
}
if (icmphdr->i_id != (USHORT)GetCurrentProcessId())
{
fprintf(stderr,"someone else's packet!\n");
return ;
}
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");
}
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);
}
其实就是使用简单sock_raw实现PING的功能
