ping.c

这个C程序是在linux下运行！发送icmp数据包进行主机攻击

/*_______________________________________________________________*\
*                                                               *\
*                                                               *\
*         Name:ping.c                                           *\
*       Author:Liang Gang & Hu Xiao-qin                         *\
*      Function:To demostrate how use raw socket to implement a *\
*               simple ping                                     *\
*          Date: 05-01-2009                                     *\
*                                                               *\
*                                                               *\
*_______________________________________________________________*/



#include <stdio.h>
#include <stdlib.h>
#include <string.h>

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

extern int errno;

int sockfd;
struct sockaddr_in addr; 
char straddr[128]; 
char sendbuf[2048];
char recvbuf[2048];
int sendnum;
int recvnum;
int datalen = 30;

#define DESTPORT 80
#define LOCALPORT 8080 

/*compute checksum*/ 
unsigned short my_cksum(unsigned short *data, int len) 
{
	int result = 0;
	int i;
	size_t count;
	
	count = strlen(data);
	for(i=0; i<len/2; i++)
	{
		result += *data;
		data++;
		count-=2;
	}
	
	if (count>0)
		result+=*(unsigned char*)data;
	
	while(result >> 16)
		result = (result&0xffff) + (result>>16);
	
	return ~result;
}
/*compute the sending data time*/
void tv_sub(struct timeval* recvtime, const struct timeval* sendtime)
{
	int sec = recvtime->tv_sec - sendtime->tv_sec;
	int usec = recvtime->tv_usec - sendtime->tv_usec;
	if(usec >= 0) 
	{
		recvtime->tv_sec = sec;
		recvtime->tv_usec = usec;
	} 
	else
	{
		recvtime->tv_sec = sec-1;
		recvtime->tv_usec = -usec;
	}
}
/*construct the icmp packet and send it*/
void send_icmp() 
{
	struct icmp* icmp = (struct icmp*)sendbuf;
	icmp->icmp_type = ICMP_ECHO;
	icmp->icmp_code = 0;
	icmp->icmp_cksum = 0;
	icmp->icmp_id = getpid(); //needn't use htons() call, because peer networking kernel didn't handle this data and won't make different meanings(bigdian litteldian) 
	icmp->icmp_seq = ++sendnum; //needn't use hotns() call too.
	gettimeofday((struct timeval*)icmp->icmp_data, NULL);
	int len = 8+datalen;
	icmp->icmp_cksum = my_cksum((unsigned short*)icmp, len);
	int retval = sendto(sockfd, sendbuf, len, 0, (struct sockaddr*)&addr, sizeof(addr));
	if(retval == -1)
	{
		perror("sendto()");
		exit(-1);
	}
	else 
	{
		printf("send icmp request to %s(%d) bytes\n", straddr, len);
	}
}

/*analysis the icmp packet and print it in screen*/

void recv_icmp()
{
	struct timeval *sendtime;
	struct timeval recvtime;
	static int index=-1;
	
	for(;;) 
	{
		int n = recvfrom(sockfd, recvbuf, sizeof(recvbuf), 0, 0, 0);
		if(n == -1)
		{
			if(errno == EINTR)continue;
			else 
			{
				perror("recvfrom()");
				exit(-1);
			}
		} 
		else 
		{
			gettimeofday(&recvtime, NULL);
			struct ip *ip = (struct ip*)recvbuf;
			if(ip->ip_src.s_addr != addr.sin_addr.s_addr) 
			{
				// printf("ip_src is not : %s\n", straddr);
				continue;
			}
			struct icmp *icmp = (struct icmp*)(recvbuf + ((ip->ip_hl)<<2));
			if(icmp->icmp_id != getpid()) 
			{
				// printf("icmp_id is not :%d\n", getpid());
				continue;
			}
			if (index==icmp->icmp_seq)
				continue;
			index = icmp->icmp_seq;
			recvnum++;
			sendtime = (struct timeval*)icmp->icmp_data;
			tv_sub(&recvtime, sendtime);
			printf("imcp echo from %s(%dbytes)\tttl=%d\tseq=%d\ttime=%d.%06d s\n", straddr, n, ip->ip_ttl, icmp->icmp_seq, recvtime.tv_sec, recvtime.tv_usec); 
		}
	}
}
void catch_sigalrm(int signum) 
{
	send_icmp();
	alarm(1);
}
void catch_sigint(int signum)
{
	printf("\nPing statics:send %d packets, recv %d packets, %d%% lost...\n", sendnum, recvnum, (int)((float)(sendnum-recvnum)/sendnum)*100);
	exit(0);
}

int main(int argc, char **argv)
{
	if(argc != 2)
	{
		printf("please use format: ping hostname\n");
		exit(-1);
	}
	
	sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
	if(sockfd == -1)
	{
		perror("socket()");
		return -1;
	}
	
	
	memset(&addr, 0, sizeof(addr));
	addr.sin_family = AF_INET;
	int retval = inet_pton(AF_INET, argv[1], &addr.sin_addr);
	if(retval == -1 || retval == 0) {
		struct hostent* host = gethostbyname(argv[1]);
		if(host == NULL) 
		{
			fprintf(stderr, "gethostbyname(%s):%s\n", argv[1], strerror(errno));
			exit(-1);
		}
		
		if(host->h_addr_list != NULL && *(host->h_addr_list) != NULL)
		{
			strncpy((char*)&addr.sin_addr, *(host->h_addr_list), 4);
			inet_ntop(AF_INET, *(host->h_addr_list), straddr, sizeof(straddr));
		}
		printf("Ping address:%s(%s)\n\n", host->h_name, straddr);
	} 
	else 
	{
		strcpy(straddr, argv[1]);
		printf("Ping address:%s(%s)\n\n", straddr, straddr);
	}
	
	struct sigaction sa1;
	memset(&sa1, 0, sizeof(sa1));
	sa1.sa_handler = catch_sigalrm;
	sigemptyset(&sa1.sa_mask);
	sa1.sa_flags = 0;
	if(sigaction(SIGALRM, &sa1, NULL) == -1)
		perror("sigaction()");
	struct sigaction sa2;
	memset(&sa2, 0, sizeof(sa2));
	sa2.sa_handler = catch_sigint;
	sigemptyset(&sa2.sa_mask);
	sa2.sa_flags = 0;
	if(sigaction(SIGINT, &sa2, NULL) == -1)
		perror("sigaction()");
	
	alarm(1);
	recv_icmp();
	
	return 0;
}