my_ping.c

ping 程序

#include "my_ping.h"
        
extern int errno;
struct proto proto_v4 = {proc_v4, send_v4, NULL, NULL,NULL, 0, IPPROTO_ICMP};

int n_send;
int n_recv; 
 
void sig_intr(int signum) {
	printf("---------------------------------\n");
	printf("success send %d packets,recvie %d packtes,lost %d packets\n", n_send, n_recv, n_send-n_recv);
	exit(0);
}
        
int main(int argc, char** argv) { 
        datalen = 56;
        int c;  
        struct addrinfo *ai;
        opterr = 0;
        while((c = getopt(argc, argv, "v")) != -1) {
                switch(c) {
                        case 'v':verbose++;break;
                        case '?':printf("error option: %c\n", c);return -1;
                }
        }
        if(optind != argc-1) {
                printf("use ping [-v] <hostname>\n");
                return -1;
        }
        host = argv[optind];
        pid = getpid(); 
        struct sigaction sa;
        sa.sa_handler = sig_alarm;
        sigaction(SIGALRM, &sa, NULL);
        
	struct sigaction sa2;
	sa2.sa_handler = sig_intr;
	sigaction(SIGINT, &sa2, NULL);
        
        printf("host:%s\n", host);
        int n = getaddrinfo(host, 0, 0, &ai);
        if(n != 0) {
                printf("error getaddrinfo()\n");
                perror("info");
        }
 
        printf("------------------------------------\n");
        printf("ai_family : %d\n", ai->ai_family);
        printf("ai_socktype:%d\n", ai->ai_socktype);
        printf("ai_protocol:%d\n", ai->ai_protocol);
        printf("ai_addrlen:%d\n", ai->ai_addrlen);
        printf("ai_canonname: %s\n", ai->ai_canonname);
        printf("------------------------------------\n");
        char buf[1024];
        const char* p;
        if(ai->ai_family == AF_INET) {
                p = inet_ntop(ai->ai_family, &(((struct sockaddr_in*)ai->ai_addr)->sin_addr), buf, 1024);
                pr = &proto_v4;
        }
        if(p == NULL)printf("error inet_ntop()\n");
        pr->sasend = ai->ai_addr;
        pr->sarecv = (struct sockaddr*)malloc(ai->ai_addrlen);
        pr->salen = ai->ai_addrlen;
 
        readloop();
 
        return 0;
}
 
void readloop(void) {
        char recvbuf[BUFSIZE];
        char controlbuf[BUFSIZE];
        struct msghdr msg;
        struct iovec iov;
        struct timeval tval;
 
        sockfd = socket(pr->sasend->sa_family, SOCK_RAW, pr->icmpproto);
        if(sockfd == -1)perror("sockfd error");
        setuid(getuid());
        int size = 60*1024;
        setsockopt(sockfd, SOL_SOCKET, SO_RCVBUF, &size, 4);
        sig_alarm(SIGALRM);
 
        iov.iov_base = recvbuf;
        iov.iov_len = sizeof(recvbuf);
        msg.msg_name = pr->sarecv;
        msg.msg_iov = &iov;
        msg.msg_iovlen = 1;
        msg.msg_control = controlbuf;
        for(;;) {
                msg.msg_namelen = pr->salen;
                msg.msg_controllen = sizeof(controlbuf);
                int n = recvmsg(sockfd, &msg, 0);
                if(n < 0) {
                        if(errno == EINTR)continue;
                        else  {
                                perror("recvmsg");
                                return;
                        }
                }
		n_recv++;
                gettimeofday(&tval, NULL);
                (*pr->fproc)(recvbuf, n, &msg, &tval);
 
        }
 
}
void tv_sub(struct timeval* out, struct timeval *in) {
        if((out->tv_usec -= in->tv_usec) < 0) {
                --out->tv_sec;
                out->tv_usec += 1000000;
        }
        out->tv_sec -= in->tv_sec;
}
void proc_v4(char* ptr, ssize_t len, struct msghdr* msg, struct timeval* tvrecv) {
        int hlen1, icmplen;
        double rtt;
        struct ip *ip;
        struct icmp *icmp;
        struct timeval *tvsend;
 
        ip = (struct ip*)ptr;
        hlen1 = ip->ip_hl << 2;
        if(ip->ip_p != IPPROTO_ICMP)return;
        icmp = (struct icmp*)(ptr + hlen1);
	
	icmplen = len-hlen1;	
        if(icmp->icmp_type == ICMP_ECHOREPLY) {
                if(icmp->icmp_id != pid) {
			printf("icmp_id doesn't equal process id\n");
			return;
		}
                if(icmplen < 0) {
			printf("icmplen less than 0\n");
			return;
		}
                tvsend = (struct timeval*)icmp->icmp_data;
                tv_sub(tvrecv, tvsend);
                rtt = tvrecv->tv_sec*1000.0 + tvrecv->tv_usec/1000.0;
		char buf[1024];
		inet_ntop(AF_INET, &(((struct sockaddr_in*)(pr->sarecv))->sin_addr), buf, 1024);
		
                printf("%d bytes from:%s id:%d rtt:%.3fms\n", icmplen, buf, icmp->icmp_seq, rtt);
        }
 
}
void send_v4(void) {
        int len;
        struct icmp *icmp;
        icmp = (struct icmp*)sendbuf;
        icmp->icmp_type = ICMP_ECHO;
        icmp->icmp_code = 0;
        icmp->icmp_id = pid;
        icmp->icmp_seq = nsent++;
        memset(icmp->icmp_data, 0xa5, datalen);
        gettimeofday((struct timeval*)icmp->icmp_data, NULL);
        len = 8+datalen;
        icmp->icmp_cksum = 0;
        icmp->icmp_cksum = in_cksum((u_short*)icmp, len);
        int n = sendto(sockfd, sendbuf, len, 0, pr->sasend, pr->salen);
	printf("success send %d bytes\n", n);
 	n_send++;
}
void sig_alarm(int signum) {
        (*pr->fsend)();
        alarm(1);
        return;
}
 
u_short in_cksum(u_short* data, int len) {
 
        int result = 0;
        for(int i=0; i<len/2; i++) {
                result += *data;
                data++;
        }
	while(result >> 16)result = (result&0xffff) + (result >> 16);
        return ~result;
 
}


/*
u_short in_cksum(u_short *addr, int len)
{
    register int nleft = len;
    register u_short *w = addr;
    register int sum = 0;
    u_short answer =0;

    while (nleft > 1)
       	{
       	sum += *w++;
       	nleft -= 2;
      	}
    if (nleft == 1)
     	{      
       	*(u_char *)(&answer) = *(u_char *)w;
        sum += answer;
     	}
    sum = (sum >> 16) + (sum & 0xffff);
    sum += (sum >> 16);
    answer = ~sum;
    return(answer);
}

*/