ping.c

linux下模拟ping的功能

/******************************************************************************\ 
* ping.c - Simple ping utility using SOCK_RAW 
* 
* This is a part of the Microsoft Source Code Samples. 
* Copyright 1996-1997 Microsoft Corporation. 
* All rights reserved. 
* This source code is only intended as a supplement to 
* Microsoft Development Tools and/or WinHelp documentation. 
* See these sources for detailed information regarding the 
* Microsoft samples programs. 
\******************************************************************************/ 

#pragma pack(4) 

#define WIN32_LEAN_AND_MEAN 
#include <winsock2.h> 
#include <stdio.h> 
#include <stdlib.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 _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 DEF_PACKET_SIZE 32 
#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); 
void decode_resp(char *,int ,struct sockaddr_in *); 

void Usage(char *progname){ 

fprintf(stderr,"Usage:\n"); 
fprintf(stderr,"%s <host> [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; 
int fromlen = sizeof(from); 
int timeout = 1000; 
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, 0,0); 

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); 

if (argc >2) { 
datasize = atoi(argv[2]); 
if (datasize == 0) 
datasize = DEF_PACKET_SIZE; 

} 
else 
datasize = DEF_PACKET_SIZE; 

datasize += sizeof(IcmpHeader); 

icmp_data = xmalloc(MAX_PACKET); 
recvbuf = 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); 

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, 
datasize); 

bwrote = sendto(sockRaw,icmp_data,datasize,0,(struct sockaddr*)&dest, 
sizeof(dest)); 
if (bwrote == SOCKET_ERROR){ 
if (WSAGetLastError() == WSAETIMEDOUT) { 
printf("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("timed out\n"); 
continue; 
} 
fprintf(stderr,"recvfrom failed: %d\n",WSAGetLastError()); 
ExitProcess(STATUS_FAILED); 
} 
decode_resp(recvbuf,bread,&from); 
Sleep(1000); 

} 
return 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); 
} 
/* 
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)); 

}