traceroute.c

Linux网络编程教程适合初学者入门学习

#include <signal.h>
#include <netinet/in.h>
#include <netdb.h>
#include <sys/socket.h>
#include  <sys/types.h> 
#include  <sys/times.h> 
#include <sys/time.h>
#include  <sys/select.h> 
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h> 
#include <fcntl.h>
#include <errno.h>

struct ip
{
#if __BYTE_ORDER == __LITTLE_ENDIAN
    unsigned int ip_hl:4;                /* little-endian IP头长度(单位为32位)4位 */
    unsigned int ip_v:4;                 /* 版本号4 IP4用4 */
#endif
#if __BYTE_ORDER == __BIG_ENDIAN
    unsigned int ip_v:4;                /*  version */
    unsigned int ip_hl:4;               /*  header length */
#endif
    u_int8_t ip_tos;                    /* 服务类型  一般为0 */
    u_short ip_len;                     /* 数据总长度 (单位为32位) */
    u_short ip_id;                      /* 标识16 */
    u_short ip_off;                     /* 分段偏移*/
#define IP_RF 0x8000                    /*  reserved fragment标志 */
#define IP_DF 0x4000                    /*  dont fragment flag */
#define IP_MF 0x2000                    /*  more fragments flag */
#define IP_OFFMASK 0x1fff               /*  mask for fragmenting bits */
    u_int8_t ip_ttl;                     /* 生存时间 */
    u_int8_t ip_p;                      /* 传输协议 tcp是6 */
    u_short ip_sum;                     /* 头校验和 */
    struct in_addr ip_src, ip_dst;      /*  源地址 目标地址 */
};

struct icmp             
{
u_int8_t  type;		/* 消息类型 */
  	u_int8_t  code;		/* 代码类型 */
  	u_int16_t checksum;	/* 校验位 */
  	union
  	{
    		u_char ih_pptr;			/* ICMP_PARAMPROB */
    		struct in_addr ih_gwaddr;	/* 网关地址 */
    		struct 					/* echo 数据包 */
{
      		u_int16_t id;
      		u_int16_t sequence;
    		} echo;

    u_int32_t ih_void;

    struct ih_pmtu
    {
     	u_int16_t ipm_void;
     	u_int16_t ipm_nextmtu;
} ih_pmtu;

    struct ih_rtradv
    {
u_int8_t irt_num_addrs;
u_int8_t irt_wpa;
u_int16_t irt_lifetime;
    } ih_rtradv;
  } un;
#define	icmp_pptr	un.ih_pptr
#define	icmp_gwaddr	un.ih_gwaddr
#define	icmp_id		un.echo.id
#define	icmp_seq	un.echo.sequence
#define	icmp_void	un.ih_void
#define	icmp_pmvoid	un.ih_pmtu.ipm_void
#define	icmp_nextmtu	un.ih_pmtu.ipm_nextmtu
#define	icmp_num_addrs	un.ih_rtradv.irt_num_addrs
#define	icmp_wpa	un.ih_rtradv.irt_wpa
#define	icmp_lifetime	un.ih_rtradv.irt_lifetime
  
union
{
    struct
    {
    		u_int32_t its_otime;
u_int32_t its_rtime;
      	u_int32_t its_ttime;
    } id_ts;
    struct
    {
    		struct ip idi_ip;
	  /* 属性阿和紧跟它的64位数据 */
    } id_ip;

  } icmp_dun;
#define	icmp_otime	icmp_dun.id_ts.its_otime
#define	icmp_rtime	icmp_dun.id_ts.its_rtime
#define	icmp_ttime	icmp_dun.id_ts.its_ttime
#define	icmp_ip		icmp_dun.id_ip.idi_ip
#define	icmp_radv	icmp_dun.id_radv
#define	icmp_mask	icmp_dun.id_mask
#define	icmp_data	icmp_dun.id_data
};


struct ip_and_icmp
{
struct  ip iph;
struct  icmp icmph;
};

/* 公共信息 */ 
char dstip[]="202.115.57.24"; 	/* 目标IP */
int	errno;
int	sends,waits;				/* 发送的socket 接收用的socket */
char info[500]; 				/* 收到的icmp信息 */
struct icmp *eicmp; 			/* TTL超时的icmp信息 */
struct ip_and_icmp *ip_icmp;		/* 收到的icmp原始信息 */
struct sockaddr_in toaddr,from;  	/* 目标地址  来信息地址 */

unsigned short csum (unsigned short *packet, int packlen)  /* 校验和计算 */
{
	register unsigned long sum = 0;

	while (packlen > 1) {
		sum+= *(packet++);
		packlen-=2;
	}

	if (packlen > 0)
		sum += *(unsigned char *)packet;

	/* 这些将取决于位顺序 */
	while (sum >> 16)
		sum = (sum & 0xffff) + (sum >> 16);

	return (unsigned short) ~sum;
}

long int send_echo(struct sockaddr_in toaddr,int id,int sq,int size,int ttlset)
/* 发送icmp ECHO信息可定目标IP,ID号,SQ号和 IP的TTL大小, */
/* 出现返回-1,否则返回发送时的时间 */
void sendicmp()
{
 int lenth;
 long int nowtime;
 char icmpbuffer[200];
 struct  icmp  *icmph;
 memset(icmpbuffer,'a', 200);
 icmph=(struct  icmp *)icmpbuffer;
 sen=socket(AF_INET,SOCK_RAW,1);
 inet_aton(toip,&toaddr.sin_addr);   /* 字符串转入地址 */
 toaddr.sin_family = AF_INET; 
 icmph->type=8;
 icmph->code=0;
 icmph->un.echo.id=htons(id);
 icmph->un.echo.sequence=htons(sq);
 icmph->checksum=htons(0);
 icmph->checksum=csum((unsigned short *)icmpbuffer,8+size);
 /* 发送的没有IP头信息 */
 setsockopt(sends, IPPROTO_IP, IP_TTL, &ttlset, sizeof(ttlset));  /* 设定TTL的大小 */
 lenth=sendto(sends,icmpbuffer,8+size,0,(struct sockaddr *)&toaddr,sizeof(toaddr));
 if (lenth>0)
 {
  	nowtime=clock();
printf("send ICMO size %d at clock %d to %s  id=%d sq=%d  \n",
size,nowtime,inet_ntoa(toaddr.sin_addr),id,sq);
  }
  else
  {
  	return -1;
  }
 return nowtime;
}

/* 等对应的ICMP REPLY信息 指定IP,ID,SQ和等待时间。*/
/* 出现ttl超时或收到返回接收到时的时间,否则为-1 */
int wait_icmp(struct sockaddr_in toaddr,int id,int sq,clock_t timesize)
{
int length,fromlength;
clock_t endclock,recvclock;
inet_aton(toip,&toaddr.sin_addr);
memset(info,'A',500);
endclock=clock()+timesize;
while(clock()<endclock)
     {
fromlength=sizeof(from);
		length=recvfrom(waits,info,sizeof(info),0,
(struct sockaddr *)&from,&fromlength);
   	   
	   if ( length>0 && (from.sin_addr.s_addr==toaddr.sin_addr.s_addr) 
&& (ip_icmp->icmph.type==0) )
   	   { 
recvclock=clock();
if ((ntohs(ip_icmp->icmph.un.echo.id)==id) 
&& (ntohs(ip_icmp->icmph.un.echo.sequence)==sq) )
		  	{
viewinfo(info,length);
		  	return recvclock;
          	}
		} /* end length>0
		if (length>0 && (ip_icmp->icmph.type==11)&&(ntohs(eicmp->icmp_id)==id) 
&& (ntohs(eicmp->icmp_seq)==sq) )   /* 11为ttl超时 */
		{
recvclock=clock();
   	 		return recvclock;
		}
    } /* end while */

return -1;  /* 超时 */
}

int main(int argc, char *argv[])
{
int rec,fromlen,n,sq,id,mstime,on=1,route=1,timeout=0,ttl;
long int iplong;
struct protoent *proto;
struct hostent *hp,*fromname; 
clock_t start,sendtime,waittime;
start = clock();
ip_icmp=(struct ip_and_icmp *)info;
eicmp=(struct icmp *)(&ip_icmp->icmph.icmp_ip+1);
id=999;
mstime=2000;
if (argc<2)
{
printf("usage: %s ip_addrs time-out(millisecond)  \n",argv[0]);
printf("       %s testping 192.168.11.38 1000  \n",argv[0]);
printf("or     %s testping 192.168.11.38   \n",argv[0]);
return 0;
}
if (argc>2)
{
mstime=atoi(argv[2]);
if (mstime<1)
    		{
printf("time-out(millisecond) is error \n");
exit (0);
}
printf("timo-out %d ms \n",mstime);
}
if ((hp = gethostbyname(argv[1])) == NULL)    /* 进入名字的分析 */
{
if ( (toaddr.sin_addr.s_addr=inet_addr(argv[1])) == -1) 
{ 
	    		fprintf(stderr, "%s: unknown host\n", argv[1]);
exit (0);
		}
		if (htonl(toaddr.sin_addr.s_addr)<0x1000001)
        	{
         		printf("error ip %s \n",inet_ntoa(toaddr.sin_addr));
         		exit (0);
        	}
     } 
else 
{
bcopy(hp->h_addr_list[0], &toaddr.sin_addr.s_addr, hp->h_length);
} 
icmph=(struct  icmphdr *)icmpbuffer;
/* 初化接收和发送用的sends */
sends=socket(AF_INET,SOCK_RAW,1);
if(setsockopt(sends, IPPROTO_IP, IP_TTL, &on, sizeof(on)) < 0)
{
perror("This is sytem can't set TTL \n"); 
exit(1); 
     }
waits=socket(AF_INET,SOCK_RAW,1);
fcntl(waits,F_SETFL,O_NDELAY); 
proto = getprotobyname("icmp");  
rec=socket(AF_INET,SOCK_RAW, proto->p_proto);
fcntl(rec,F_SETFL,O_NDELAY); 
printf("%s \n",sys_errlist[errno]);
if (rec<0)
{
exit(0);
}
printf("now to wait... at %d \n",start);
/* waiting for packets */
inet_aton(dstip,&toaddr.sin_addr);
printf("send ICMO  to %s  \n",inet_ntoa(toaddr.sin_addr));
   	id=999;  		/* 初始化ID */
sq=0;   		/* 初始化sq */
timeout=0;  	/* time out次数 */
ttl=1;    /* ttl 值 */
while (1)
{
sq++;
sendtime=send_echo(toaddr,id,sq*100,20,ttl);	/* 发送ICMP ECHO */
/* 目标IP  编号  长度 ttl */
if (sendtime==-1)
{
printf("end error \n");
exit (0);
}
waittime=wait_icmp(toaddr,id,sq*100,mstime*1000); /* 接收ICMP ECHO */

if (waittime==-1)
{
if (timeout==4)  /* 连续4次time out退出 */
{
printf("time out >3 end \n");
exit (1);
}
printf("time out \n");
timeout++;
}
     else 
{
if (ip_icmp->icmph.type==0)
{
printf("%02d ",route);
printf(" %04d ms ",(waittime-sendtime)/1000);
printf("  %s ",inet_ntoa(ip_icmp->iph.ip_src));
printf("\n");
printf("\n");
printf("Trace complete \n");
break;
}
if (ip_icmp->icmph.type==11)
{
timeout=0;
ttl++;   			/* 接收到一个ttl超时信息TTL值加1 */
printf("%02d ",route);
printf(" %04d ms ",(waittime-sendtime)/1000);
printf("  %s ",inet_ntoa(ip_icmp->iph.ip_src));
printf("\n");
route++;
}
} /* end else waittime==-1 */
} /* end for */
}