461.htm

unix高级编程原吗

      (struct sockaddr *)&dst, <br>
      sizeof(dst)) < 0) { <br>
   perror("sendto"); <br>
  } <br>
  if (delay) <br>
   usleep(delay); <br>
  /* Don't flood the pipeline..kind of arbitrary */ <br>
  head = head->next; <br>
 } <br>
} <br>
  <br>
void myexit(int whatsig) <br>
{ <br>
 exit(0); <br>
 exit(0); <br>
} <br>
  <br>
/* <br>
 * Listen for 'hostcount' pings, print out the information, and <br>
 * then exit. <br>
 */ <br>
  <br>
void recvpings(int s, int querytype, struct hostdesc *head, int hostcount) <br>
{ <br>
 char buf[1500]; <br>
 struct ip *ip = (struct ip *)buf; <br>
 struct icmp *icmp; <br>
 int err = 0; <br>
 long int fromlen = 0; <br>
 int hlen; <br>
 struct timeval *tp; <br>
 struct timeval tv; <br>
 int recvd = 0; <br>
 char *hostto; <br>
 char hostbuf[128];  /* We'll print the address here otherwise */ <br>
 struct hostdesc *foundhost; <br>
  <br>
  <br>
 gettimeofday(&tv, NULL); <br>
  <br>
 while (recvd < hostcount) { <br>
  if ((err = recvfrom(s, buf, sizeof buf, 0, NULL, <br>
        (int *)&fromlen)) < 0) <br>
  { <br>
   perror("icmpquery:  recvfrom"); <br>
  } <br>
  <br>
  hlen = ip->ip_hl << 2; <br>
  icmp = (struct icmp *)(buf + hlen); <br>
  <br>
  /* Find the host */ <br>
  hostto = 0; <br>
  for (foundhost = head; foundhost != NULL; <br>
       foundhost = foundhost->next) { <br>
   if (foundhost->hostaddr.s_addr == ip->ip_src.s_addr) { <br>
    hostto = foundhost->hostname; <br>
    break; <br>
   } <br>
  } <br>
  <br>
  <br>
  if (!hostto) { <br>
   sprintf(hostbuf, "unknown (%s)", <br>
    inet_ntoa(ip->ip_src)); <br>
   hostto = hostbuf; <br>
  } <br>
  <br>
  /* For time */ <br>
  switch(icmp->icmp_type) { <br>
  case ICMP_TSTAMPREPLY: <br>
   fromlen = ntohl(icmp->icmp_ttime); <br>
    /* ms since midnight. yuch. */ <br>
   tv.tv_usec = fromlen; <br>
   tv.tv_usec = 0; <br>
   tv.tv_sec -= tv.tv_sec%(24*60*60); <br>
   tv.tv_sec += (fromlen/1000); <br>
   tv.tv_usec = (fromlen%1000); <br>
   printf("%-40.40s:  %s", hostto, ctime(&(tv.tv_sec))); <br>
   break; <br>
  <br>
  case ICMP_MASKREPLY: <br>
   fromlen = ntohl(icmp->icmp_dun.id_mask); <br>
   printf("%-40.40s:  0x%lX\n", hostto, fromlen); <br>

   break; <br>
  <br>
  default: <br>
   printf("Unknown ICMP message received (type %d)\n", <br>
          icmp->icmp_type); <br>
  } <br>
  recvd++; <br>
 } <br>
} <br>
  <br>
int <br>
main(int argc, char **argv) <br>
{ <br>
   int s; <br>
  <br>
   char *progname; <br>
   extern char *optarg;         /* getopt variable declarations */ <br>
   char *hostfrom = NULL; <br>
   extern int optind; <br>
   extern int optopt; <br>
   extern int opterr; <br>
   char ch;                     /* Holds the getopt result */ <br>

   int on = 1; <br>
   int hostcount; <br>
   int delay = 0; <br>
   int querytype = ICMP_TSTAMP; <br>
   struct in_addr fromaddr; <br>
   int timeout = 5;  /* Default to 5 seconds */ <br>
  <br>
   fromaddr.s_addr = 0; <br>
  <br>
   progname = argv[0]; <br>
  <br>
   while ((ch = getopt(argc, argv, "tmf:d:T:")) != EOF) <br>
      switch(ch) <br>
      { <br>
      case 'd': <br>
       delay = (int) strtol(optarg, NULL, 10); <br>
       break; <br>
      case 't': /* timestamp request */ <br>
       querytype = ICMP_TSTAMP; <br>
       break; <br>
      case 'm': /* address mask request */ <br>
       querytype = ICMP_MASKREQ; <br>

       break; <br>
      case 'f': <br>
       hostfrom = optarg; <br>
       resolv_from(hostfrom, &fromaddr); <br>
       break; <br>
      case 'T': <br>
       timeout = (int) strtol(optarg, NULL, 10); <br>
       break; <br>
      default: <br>
       usage(progname); <br>
       exit(-1); <br>
      } <br>
   argc -= optind; <br>
   argv += optind; <br>
  <br>
   if (!argv[0] || !strlen(argv[0])) <br>
   { <br>
      usage(progname); <br>
      exit(-1); <br>
   } <br>
  <br>
   hostcount = makehosts(argv); <br>

  <br>
   if ((s = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP)) < 0) { <br>
      perror("socket"); <br>
      exit(1); <br>
   } <br>
   if (setsockopt(s, IPPROTO_IP, IP_HDRINCL, &on, sizeof(on)) < 0) { <br>
      perror("IP_HDRINCL"); <br>
      exit(1); <br>
   } <br>
  <br>
   signal(SIGALRM, myexit); <br>
   alarm(timeout); <br>
   sendpings(s, querytype, hostnames, delay, fromaddr); <br>
   recvpings(s, querytype, hostnames, hostcount); <br>
} <br>
  <br>
/* <br>
 * in_cksum -- <br>
 * Checksum routine for Internet Protocol family headers (C Version) <br>
 *      From FreeBSD's ping.c <br>
 */ <br>
  <br>
  <br>
in_cksum(addr, len) <br>
 u_short *addr; <br>
 int len; <br>
{ <br>
 register int nleft = len; <br>
 register u_short *w = addr; <br>
 register int sum = 0; <br>
 u_short answer = 0; <br>
  <br>
 /* <br>
  * Our algorithm is simple, using a 32 bit accumulator (sum), we add <br>
  * sequential 16 bit words to it, and at the end, fold back all the <br>
  * carry bits from the top 16 bits into the lower 16 bits. <br>
  */ <br>
 while (nleft > 1)  { <br>
  sum += *w++; <br>
  nleft -= 2; <br>
 } <br>
  <br>
 /* mop up an odd byte, if necessary */ <br>
 if (nleft == 1) { <br>
  *(u_char *)(&answer) = *(u_char *)w ; <br>

  sum += answer; <br>
 } <br>
  <br>
 /* add back carry outs from top 16 bits to low 16 bits */ <br>
 sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */ <br>
 sum += (sum >> 16);   /* add carry */ <br>
 answer = ~sum;    /* truncate to 16 bits */ <br>
 return(answer); <br>
} <br>
  <br>
  <br>
/* <br>
 * Copyright (c) 1989, 1993 <br>
 *      The Regents of the University of California.  All rights reserved. <br>
 * <br>
 * This code is derived from software contributed to Berkeley by <br>
 * Mike Muuss. <br>
 * <br>
 * Redistribution and use in source and binary forms, with or without <br>
 * modification, are permitted provided that the following conditions <br>
 * are met: <br>
 * 1. Redistributions of source code must retain the above copyright <br>

 *    notice, this list of conditions and the following disclaimer. <br>
 * 2. Redistributions in binary form must reproduce the above copyright <br>
 *    notice, this list of conditions and the following disclaimer in the <br>
 *    documentation and/or other materials provided with the distribution. <br>
 * 3. All advertising materials mentioning features or use of this software <br>
 *    must display the following acknowledgement: <br>
 *      This product includes software developed by the University of <br>
 *      California, Berkeley and its contributors. <br>
 * 4. Neither the name of the University nor the names of its contributors <br>
 *    may be used to endorse or promote products derived from this software <br>
 *    without specific prior written permission. <br>
 * <br>
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND <br>
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE <br>
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE <br>
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE <br>
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL <br>
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS <br>
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) <br>
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT <br>
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY <br>
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF <br>

 * SUCH DAMAGE. <br>
 */ <br>
</small><hr>
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