003.同时Ping多个IP（select实现IO复用，信号计时），ping程序升级版

写这个的目的主要是为了以后的方便：

1.信号计时函数的使用

2.ip头的构建和icmp头的构建

3.selec函数t的用法

代码实现：

/src/ping.h

 /*
  * ping.h
  *
  *  Created on: 2015年11月6日
  *      Author: root
  */

 #ifndef PING_H_
 #define PING_H_

 #endif /* PING_H_ */

 #include <sys/types.h>
 #include <sys/select.h>
 #include <stdio.h>
 #include <string.h>
 #include <netdb.h>
 #include <arpa/inet.h>
 #include <unistd.h>
 #include <signal.h>
 #include <sys/time.h>
 #include <sys/socket.h>
 #include <netinet/ip_icmp.h>
 #include<errno.h>    /*sys/types.h中文名称为基本系统数据类型*/

 #define N 200005
 #define PACKET_SIZE 1024*4

 extern FILE *out;
 extern int nsent;
 extern int nrecv;

 extern char * intip_to_ipv4(unsigned int ip);
 extern void recv_all_packet(int sockfd);
 extern int send_one_packet(int sockfd, unsigned int ip_num, int pid);

/src/ping.h

/src/ping_project.c

 /*
  ============================================================================
  Name        : ping_project.c
  Author      : huh
  Version     :
  Copyright   : ---notice---
  Description : Hello World in C, Ansi-style
  ============================================================================
  */

 #include "ping.h"

 FILE *out;

 int pid;
 int the_number_of_ping = ;
 int send_sockfd, recv_sockfd;
 int ping_num = ;  //ip地址数量
 unsigned int addr[N];  //ip地址数组
 struct sigaction act_alarm;
 struct timeval timeout;
 struct itimerval val_alarm ={
         .it_interval.tv_sec = ,
         .it_interval.tv_usec = ,
         .it_value.tv_sec = ,
         .it_value.tv_usec =  };
 fd_set init_recv_sockets, recv_sockets;
 fd_set init_send_sockets, send_sockets, init_send_sockets_2;

 int size =  * ;

 void init_ip();
 void sig_alrm(int singo);

 int main(void)
 {
     init_ip();
     out = fopen("./src/file/a.out", "w");
     if (out == NULL)
     {
         perror("stdout error!\n");
     }
     int flag1, flag2;
     pid = getpid();
     send_sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
     //if(send_sockfd < 0)    {        perror("send_sockfd error:");        return 0;    }
     flag1 = setsockopt(send_sockfd, IPPROTO_IP, IP_HDRINCL, &size,
             sizeof(size));
     //if(flag1<0)     {        perror("setsockopt error:");        return 0;    }
     recv_sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
     //if(recv_sockfd < 0)    {        perror("recv_sockfd error:");        return 0;    }
     flag2 = setsockopt(recv_sockfd, IPPROTO_IP, IP_HDRINCL, &size,
             sizeof(size));
     //if(flag2<0)     {        perror("setsockopt error:");        return 0;    }

     act_alarm.sa_handler = sig_alrm;
     if (sigaction(SIGALRM, &act_alarm, NULL) == -)
         printf("SIGALRM handler setting fails.\n");

     if ((setitimer(ITIMER_REAL, &val_alarm, NULL)) == -) /*定时函数*/
         printf("setitimer fails.\n");

     int result;
     int maxfdp1;
     int k = ;

     FD_ZERO(&init_recv_sockets);
     FD_SET(recv_sockfd, &init_recv_sockets);

     FD_ZERO(&init_send_sockets);
     FD_SET(send_sockfd, &init_send_sockets);
     init_send_sockets_2 = init_send_sockets;

     maxfdp1 = recv_sockfd + ;
     while () //无限循环，接受包
     {
         recv_sockets = init_recv_sockets;
         send_sockets = init_send_sockets_2;
         timeout.tv_sec = ;
         timeout.tv_usec = ;
         result = select(maxfdp1, &recv_sockets, &send_sockets, NULL, &timeout);
         switch (result)
         {
         case :
             printf("共发送了%d个包, 收到了%d个包\n", nsent, nrecv);
             printf("timeout:程序结束！\n");
             return ;
             break;
         case -:
             if (errno == EINTR)
                 continue;
             perror("select:");
             return ;
             break;
         default:
             if (FD_ISSET(recv_sockfd, &recv_sockets))
                 recv_all_packet(recv_sockfd);
             if (FD_ISSET(send_sockfd, &send_sockets))
             {
                 send_one_packet(send_sockfd, addr[k], pid);
                 k = (k + ) % ping_num;
                 if (k == )
                     FD_ZERO(&init_send_sockets_2);
             }
             break;
         }
     }
     return ;
 }

 void sig_alrm(int singo)
 {
     the_number_of_ping++;
     if (the_number_of_ping <= )
     {
         printf("ping了第%d遍！\n", the_number_of_ping);
         init_send_sockets_2 = init_send_sockets;
     } else
     {
         val_alarm.it_interval.tv_sec = ;
         val_alarm.it_interval.tv_usec = ;
         val_alarm.it_value = val_alarm.it_interval;
         setitimer(ITIMER_REAL, &val_alarm, NULL);
     }
 }

 void init_ip()  //将要访问的主机全部变成32位无符号的ip。
 {
     FILE *in;
     unsigned int name;
     char str[];
     struct hostent *host;

     in = freopen("./src/file/a.in", "r", stdin);
     if (in == NULL)
     {
         printf("stdin error!\n");
     }

     while (!feof(in))
     {
         scanf("%s", str);  //ip地址或域名
         name = inet_addr(str);  //将一个点分十进制IP转化为长整数
         if (name == INADDR_NONE)
         {
             host = gethostbyname(str);
             if (host == NULL)
             {
                 printf("参数格式不正确，请重新输入！\n");
                 continue;
             }
             memcpy((char*) &name, host->h_addr, );
         }
         addr[ping_num] = name;
         printf("%s:%s\n", str, intip_to_ipv4(name));
         ping_num++;
     }
     printf("程序将 ping %d 个IP.\n", ping_num);
 }

/src/ping_project.c

/src/send.c

 /*
  * send.c
  *
  *  Created on: 2015年11月6日
  *      Author: root
  */

 #include "ping.h"

 int icmp_len;
 int flag;
 int nsent=;
 int datalen = ;
 struct icmp *icmp;
 char sendbuf[PACKET_SIZE];
 struct sockaddr_in dest_addr; //socket目的地址

 unsigned short cal_chksum(unsigned short *addr, int len)
 {
     int nleft = len;
     int sum = ;
     unsigned short *w = addr;
     unsigned short answer = ;
     //把ICMP报头二进制数据以2字节为单位累加起来
     while (nleft > )
     {
         sum += *w++;
         nleft -= ;
     }
     if (nleft == )
     {
         *(unsigned char *)(&answer) = *(unsigned char *)w;
         sum += answer;
     }
     sum = (sum>>) + (sum&0xffff);
     sum += (sum>>);
     answer = ~sum;
     return answer;
 }

 char * intip_to_ipv4(unsigned int ip)
 {
     char *str;
     struct in_addr des;
     des.s_addr = ip;
     str = inet_ntoa(des);
     //printf("---%s---\n",str);
     return str;
 }

 int send_one_packet(int sockfd, unsigned int ip_num, int pid)
 {
     struct iphdr *ip;
     ip = (struct iphdr *)sendbuf;
     ip->ihl = sizeof(struct iphdr) >> ; //首部长度
     ip->version = ; //ip协议版本
     ip->tos = ; //服务类型字段
     ip->tot_len = ; //总长度
     ip->id = ;
     ip->frag_off = ;
     ip->ttl = ;
     ip->protocol = IPPROTO_ICMP;
     ip->check = ;  //让内核算

     dest_addr.sin_family = AF_INET;
     memcpy((char *)&dest_addr.sin_addr, (char *)&ip_num,sizeof(ip_num));
     //ip->saddr = src_addr.sin_addr.s_addr;
     ip->daddr = dest_addr.sin_addr.s_addr;

     icmp = (struct icmp *)(sendbuf + sizeof(struct iphdr));
     icmp->icmp_type = ICMP_ECHO;  //拼接icmp
     icmp->icmp_code = ;
     icmp->icmp_id = pid;   //2字节
     icmp->icmp_seq = ++nsent; //2字节
     memset(icmp->icmp_data, 0xa5, datalen);
     gettimeofday((struct timeval *)icmp->icmp_data, NULL);    //将发送时间作为数据传递过去

     icmp_len = datalen + ;
     icmp->icmp_cksum = ;
     icmp->icmp_cksum = cal_chksum((unsigned short *)icmp, icmp_len);

     flag = sendto(sockfd, sendbuf, ip->tot_len, , (struct sockaddr *)&dest_addr, sizeof(dest_addr));  //将包发出去
     //if(flag < 0) {    printf("sendto error!\n");    return 0; }

     fprintf(out,"inet addr:%s 's packet have sent!\n",intip_to_ipv4(ip_num));
     return ;
 }

/src/send.c

/src/recv.c

 /*
  * recv.c
  *
  *  Created on: 2015年11月6日
  *      Author: root
  */

 #include "ping.h"

 int nrecv=;
 struct timeval tvrecv;
 char recvbuf[PACKET_SIZE];
 struct sockaddr_in src_addr; //socket源地址

 int len;  //统计收到的包的长度
 int src_addr_len = sizeof(struct sockaddr_in);

 void tv_sub(struct timeval *out,struct timeval *in)
 {
     if ((out->tv_usec-=in->tv_usec) < )
     {
         --out->tv_sec;
         out->tv_usec += ;
     }
     out->tv_sec -= in->tv_sec;
 }

 void unpacket(int sockfd, int len,int pid)
 {
     //int len;
     double rtt;
     int iphdrlen;
     struct ip *ip;
     struct icmp *icmp;
     struct timeval *tvsend;

     gettimeofday(&tvrecv,NULL);
     ip = (struct ip *)recvbuf;
     iphdrlen = ip->ip_hl<<;
     //printf("%d\n",iphdrlen);
     icmp = (struct icmp *)(recvbuf+iphdrlen);
     len -= iphdrlen;

     if((icmp->icmp_type == ICMP_ECHOREPLY) && (icmp->icmp_id == pid))
     {
         tvsend = (struct timeval *)icmp->icmp_data;
         tv_sub(&tvrecv, tvsend);//接收和发送的时间差
         rtt = tvrecv.tv_sec*1000.0 + (1.0*tvrecv.tv_usec)*0.001;//以毫秒单位计算rtt
         fprintf(out,"%d byte from %s: icmp_seq=%u ttl=%d rtt=%.3f ms\n", len, inet_ntoa(ip->ip_src), icmp->icmp_seq, ip->ip_ttl, rtt);
         nrecv++;
     }
     //sleep(1);
 }

 void recv_all_packet(int recv_sockfd)
 {
     len = recvfrom(recv_sockfd, recvbuf, sizeof(recvbuf), , (struct sockaddr *)&src_addr, (socklen_t *)&src_addr_len);
     if(len < )
         perror("recvfrom:");
     unpacket(recv_sockfd, len, getpid());
     return ;
 }

/src/recv.c

/src/file/a.in

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/src/file/a.in