Ping sorucecode: ping.c

/*
 * Copyright (c) 1989 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Mike Muuss.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *  This product includes software developed by the University of
 *  California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

char copyright[] =
  "@(#) Copyright (c) 1989 The Regents of the University of California.\n"
  "All rights reserved.\n";
/*
 * From: @(#)ping.c  5.9 (Berkeley) 5/12/91
 */
char rcsid[] = "$Id: ping.c,v 1.22 1997/06/08 19:39:47 dholland Exp $";
char pkg[] = "netkit-base-0.10";

/*
 *      P I N G . C
 *
 * Using the InterNet Control Message Protocol (ICMP) "ECHO" facility,
 * measure round-trip-delays and packet loss across network paths.
 *
 * Author -
 *  Mike Muuss
 *  U. S. Army Ballistic Research Laboratory
 *  December, 1983
 *
 * Status -
 *  Public Domain.  Distribution Unlimited.
 * Bugs -
 *  More statistics could always be gathered.
 *  This program has to run SUID to ROOT to access the ICMP socket.
 */

#include <sys/param.h>
#include <sys/socket.h>
#include <sys/file.h>
#include <sys/time.h>
#include <sys/signal.h>

#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <ctype.h>
#include <errno.h>

/*
 * Note: on some systems dropping root makes the process dumpable or
 * traceable. In that case if you enable dropping root and someone
 * traces ping, they get control of a raw socket and can start
 * spoofing whatever packets they like. SO BE CAREFUL.
 */
#ifdef __linux__
#define SAFE_TO_DROP_ROOT
#endif

#if defined(__GLIBC__) && (__GLIBC__ >= 2)
#define icmphdr      icmp
#define ICMP_DEST_UNREACH  ICMP_UNREACH
#define ICMP_NET_UNREACH  ICMP_UNREACH_NET
#define ICMP_HOST_UNREACH  ICMP_UNREACH_HOST
#define ICMP_PORT_UNREACH  ICMP_UNREACH_PORT
#define ICMP_PROT_UNREACH  ICMP_UNREACH_PROTOCOL
#define ICMP_FRAG_NEEDED  ICMP_UNREACH_NEEDFRAG
#define ICMP_SR_FAILED    ICMP_UNREACH_SRCFAIL
#define ICMP_NET_UNKNOWN  ICMP_UNREACH_NET_UNKNOWN
#define ICMP_HOST_UNKNOWN  ICMP_UNREACH_HOST_UNKNOWN
#define ICMP_HOST_ISOLATED  ICMP_UNREACH_ISOLATED
#define ICMP_NET_UNR_TOS  ICMP_UNREACH_TOSNET
#define ICMP_HOST_UNR_TOS  ICMP_UNREACH_TOSHOST
#define ICMP_SOURCE_QUENCH  ICMP_SOURCEQUENCH
#define ICMP_REDIR_NET    ICMP_REDIRECT_NET
#define ICMP_REDIR_HOST    ICMP_REDIRECT_HOST
#define ICMP_REDIR_NETTOS  ICMP_REDIRECT_TOSNET
#define ICMP_REDIR_HOSTTOS  ICMP_REDIRECT_TOSHOST
#define ICMP_TIME_EXCEEDED  ICMP_TIMXCEED
#define ICMP_EXC_TTL    ICMP_TIMXCEED_INTRANS
#define ICMP_EXC_FRAGTIME  ICMP_TIMXCEED_REASS
#define  ICMP_PARAMETERPROB  ICMP_PARAMPROB
#define ICMP_TIMESTAMP    ICMP_TSTAMP
#define ICMP_TIMESTAMPREPLY  ICMP_TSTAMPREPLY
#define ICMP_INFO_REQUEST  ICMP_IREQ
#define ICMP_INFO_REPLY    ICMP_IREQREPLY
#else
#define ICMP_MINLEN  28
#define inet_ntoa(x) inet_ntoa(*((struct in_addr *)&(x)))
#endif


#define  DEFDATALEN  (64 - 8)  /* default data length */
#define  MAXIPLEN  60
#define  MAXICMPLEN  76
#define  MAXPACKET  (65536 - 60 - 8)/* max packet size */
#define  MAXWAIT    10    /* max seconds to wait for response */
#define  NROUTES    9    /* number of record route slots */

#define  A(bit)    rcvd_tbl[(bit)>>3]  /* identify byte in array */
#define  B(bit)    (1 << ((bit) & 0x07))  /* identify bit in byte */
#define  SET(bit)  (A(bit) |= B(bit))
#define  CLR(bit)  (A(bit) &= (~B(bit)))
#define  TST(bit)  (A(bit) & B(bit))

/* various options */
int options;
#define  F_FLOOD    0x001
#define  F_INTERVAL  0x002
#define  F_NUMERIC  0x004
#define  F_PINGFILLED  0x008
#define  F_QUIET    0x010
#define  F_RROUTE  0x020
#define  F_SO_DEBUG  0x040
#define  F_SO_DONTROUTE  0x080
#define  F_VERBOSE  0x100

/* multicast options */
int moptions;
#define MULTICAST_NOLOOP  0x001
#define MULTICAST_TTL    0x002
#define MULTICAST_IF    0x004

/*
 * MAX_DUP_CHK is the number of bits in received table, i.e. the maximum
 * number of received sequence numbers we can keep track of.  Change 128
 * to 8192 for complete accuracy...
 */
#define  MAX_DUP_CHK  (8 * 128)
int mx_dup_ck = MAX_DUP_CHK;
char rcvd_tbl[MAX_DUP_CHK / 8];

struct sockaddr whereto;  /* who to ping */
int datalen = DEFDATALEN;
int s;        /* socket file descriptor */
u_char outpack[MAXPACKET];
char BSPACE = '\b';    /* characters written for flood */
char DOT = '.';
static char *hostname;
static int ident;    /* process id to identify our packets */

/* counters */
static long npackets;    /* max packets to transmit */
static long nreceived;    /* # of packets we got back */
static long nrepeats;    /* number of duplicates */
static long ntransmitted;  /* sequence # for outbound packets = #sent */
static int interval = 1;  /* interval between packets */

/* timing */
static int timing;    /* flag to do timing */
static long tmin = LONG_MAX;  /* minimum round trip time */
static long tmax = 0;    /* maximum round trip time */
static u_long tsum;    /* sum of all times, for doing average */

/* protos */
static char *pr_addr(u_long);
static int in_cksum(u_short *addr, int len);
static void catcher(int);
static void finish(int ignore);
static void pinger(void);
static void fill(void *bp, char *patp);
static void usage(void);
static void pr_pack(char *buf, int cc, struct sockaddr_in *from);
static void tvsub(struct timeval *out, struct timeval *in);
static void pr_icmph(struct icmphdr *icp);
static void pr_retip(struct iphdr *ip);


int
main(int argc, char *argv[])
{
  struct timeval timeout;
  struct hostent *hp;
  struct sockaddr_in *to;
  struct protoent *proto;
  struct in_addr ifaddr;
  int i;
  int ch, fdmask, hold, packlen, preload;
  u_char *datap, *packet;
  char *target, hnamebuf[MAXHOSTNAMELEN];
  u_char ttl, loop;
  int am_i_root;
#ifdef IP_OPTIONS
  char rspace[3 + 4 * NROUTES + 1];  /* record route space */
#endif

  static char *null = NULL;
  __environ = &null;
  am_i_root = (getuid()==0);

  /*
   * Pull this stuff up front so we can drop root if desired.
   */
  if (!(proto = getprotobyname("icmp"))) {
    (void)fprintf(stderr, "ping: unknown protocol icmp.\n");
    exit(2);
  }
  if ((s = socket(AF_INET, SOCK_RAW, proto->p_proto)) < 0) {
    if (errno==EPERM) {
      fprintf(stderr, "ping: ping must run as root\n");
    }
    else perror("ping: socket");
    exit(2);
  }

#ifdef SAFE_TO_DROP_ROOT
  setuid(getuid());
#endif

  preload = 0;
  datap = &outpack[8 + sizeof(struct timeval)];
  while ((ch = getopt(argc, argv, "I:LRc:dfh:i:l:np:qrs:t:v")) != EOF)
    switch(ch) {
    case 'c':
      npackets = atoi(optarg);
      if (npackets <= 0) {
        (void)fprintf(stderr,
            "ping: bad number of packets to transmit.\n");
        exit(2);
      }
      break;
    case 'd':
      options |= F_SO_DEBUG;
      break;
    case 'f':
      if (!am_i_root) {
        (void)fprintf(stderr,
            "ping: %s\n", strerror(EPERM));
        exit(2);
      }
      options |= F_FLOOD;
      setbuf(stdout, NULL);
      break;
    case 'i':    /* wait between sending packets */
      interval = atoi(optarg);
      if (interval <= 0) {
        (void)fprintf(stderr,
            "ping: bad timing interval.\n");
        exit(2);
      }
      options |= F_INTERVAL;
      break;
    case 'l':
      if (!am_i_root) {
        (void)fprintf(stderr,
            "ping: %s\n", strerror(EPERM));
        exit(2);
      }
      preload = atoi(optarg);
      if (preload < 0) {
        (void)fprintf(stderr,
            "ping: bad preload value.\n");
        exit(2);
      }
      break;
    case 'n':
      options |= F_NUMERIC;
      break;
    case 'p':    /* fill buffer with user pattern */
      options |= F_PINGFILLED;
      fill(datap, optarg);
      break;
    case 'q':
      options |= F_QUIET;
      break;
    case 'R':
      options |= F_RROUTE;
      break;
    case 'r':
      options |= F_SO_DONTROUTE;
      break;
    case 's':    /* size of packet to send */
      datalen = atoi(optarg);
      if (datalen > MAXPACKET) {
        (void)fprintf(stderr,
            "ping: packet size too large.\n");
        exit(2);
      }
      if (datalen <= 0) {
        (void)fprintf(stderr,
            "ping: illegal packet size.\n");
        exit(2);
      }
      break;
    case 'v':
      options |= F_VERBOSE;
      break;
    case 'L':
      moptions |= MULTICAST_NOLOOP;
      loop = 0;
      break;
    case 't':
      moptions |= MULTICAST_TTL;
      i = atoi(optarg);
      if (i < 0 || i > 255) {
        printf("ttl %u out of range\n", i);
        exit(2);
      }
      ttl = i;
      break;
    case 'I':
      moptions |= MULTICAST_IF;
      {
        int i1, i2, i3, i4;
        char junk;

        if (sscanf(optarg, "%u.%u.%u.%u%c",
             &i1, &i2, &i3, &i4, &junk) != 4) {
          printf("bad interface address '%s'\n",
                 optarg);
          exit(2);
        }
        ifaddr.s_addr = (i1<<24)|(i2<<16)|(i3<<8)|i4;
        ifaddr.s_addr = htonl(ifaddr.s_addr);
      }
      break;
    default:
      usage();
    }
  argc -= optind;
  argv += optind;
  
  if (argc != 1)
    usage();
  target = *argv;

  memset(&whereto, 0, sizeof(struct sockaddr));
  to = (struct sockaddr_in *)&whereto;
  to->sin_family = AF_INET;
  if (inet_aton(target, &to->sin_addr)) {
    hostname = target;
  }
  else {
    hp = gethostbyname(target);
    if (!hp) {
      (void)fprintf(stderr,
          "ping: unknown host %s\n", target);
      exit(2);
    }
    to->sin_family = hp->h_addrtype;
    if (hp->h_length > (int)sizeof(to->sin_addr)) {
      hp->h_length = sizeof(to->sin_addr);
    }
    memcpy(&to->sin_addr, hp->h_addr, hp->h_length);
    (void)strncpy(hnamebuf, hp->h_name, sizeof(hnamebuf) - 1);
    hostname = hnamebuf;
  }

  if (options & F_FLOOD && options & F_INTERVAL) {
    (void)fprintf(stderr,
        "ping: -f and -i incompatible options.\n");
    exit(2);
  }

  if (datalen >= (int)sizeof(struct timeval)) /* can we time transfer */
    timing = 1;
  packlen = datalen + MAXIPLEN + MAXICMPLEN;
  packet = malloc((u_int)packlen);
  if (!packet) {
    (void)fprintf(stderr, "ping: out of memory.\n");
    exit(2);
  }
  if (!(options & F_PINGFILLED))
    for (i = 8; i < datalen; ++i)
      *datap++ = i;

  ident = getpid() & 0xFFFF;
  hold = 1;

  if (options & F_SO_DEBUG)
    (void)setsockopt(s, SOL_SOCKET, SO_DEBUG, (char *)&hold,
        sizeof(hold));

  if (options & F_SO_DONTROUTE)
    (void)setsockopt(s, SOL_SOCKET, SO_DONTROUTE, (char *)&hold,
        sizeof(hold));

  /* this is necessary for broadcast pings to work */
  setsockopt(s, SOL_SOCKET, SO_BROADCAST, (char *)&hold, sizeof(hold));

  /* record route option */
  if (options & F_RROUTE) {
#ifdef IP_OPTIONS
          memset(rspace, 0, sizeof(rspace));
    rspace[IPOPT_OPTVAL] = IPOPT_RR;
    rspace[IPOPT_OLEN] = sizeof(rspace)-1;
    rspace[IPOPT_OFFSET] = IPOPT_MINOFF;
    if (setsockopt(s, IPPROTO_IP, IP_OPTIONS, rspace,
        sizeof(rspace)) < 0) {
      perror("ping: record route");
      exit(2);
    }
#else
    (void)fprintf(stderr,
      "ping: record route not available in this implementation.\n");
    exit(2);
#endif /* IP_OPTIONS */
  }

  /*
   * When pinging the broadcast address, you can get a lot of answers.
   * Doing something so evil is useful if you are trying to stress the
   * ethernet, or just want to fill the arp cache to get some stuff for
   * /etc/ethers.
   */
  hold = 48 * 1024;
  (void)setsockopt(s, SOL_SOCKET, SO_RCVBUF, (char *)&hold,
      sizeof(hold));

/*#if 0*/
  if (moptions & MULTICAST_NOLOOP) {
    if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_LOOP,
              &loop, 1) == -1) {
      perror ("can't disable multicast loopback");
      exit(92);
    }
  }
  if (moptions & MULTICAST_TTL) {
    if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_TTL,
              &ttl, 1) == -1) {
      perror ("can't set multicast time-to-live");
      exit(93);
    }
  }
  if (moptions & MULTICAST_IF) {
    if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF,
          &ifaddr, sizeof(ifaddr)) == -1) {
      perror ("can't set multicast source interface");
      exit(94);
    }
  }
/*#endif*/

  if (to->sin_family == AF_INET)
    (void)printf("PING %s (%s): %d data bytes\n", hostname,
        inet_ntoa(*(struct in_addr *)&to->sin_addr.s_addr),
        datalen);
  else
    (void)printf("PING %s: %d data bytes\n", hostname, datalen);

  (void)signal(SIGINT, finish);
  (void)signal(SIGALRM, catcher);

  while (preload--)    /* fire off them quickies */
    pinger();

  if ((options & F_FLOOD) == 0)
    catcher(0);    /* start things going */

  for (;;) {
    struct sockaddr_in from;
    register int cc;
    size_t fromlen;

    if (options & F_FLOOD) {
      pinger();
      timeout.tv_sec = 0;
      timeout.tv_usec = 10000;
      fdmask = 1 << s;
      if (select(s + 1, (fd_set *)&fdmask, (fd_set *)NULL,
          (fd_set *)NULL, &timeout) < 1)
        continue;
    }
    fromlen = sizeof(from);
    if ((cc = recvfrom(s, (char *)packet, packlen, 0,
        (struct sockaddr *)&from, &fromlen)) < 0) {
      if (errno == EINTR)
        continue;
      perror("ping: recvfrom");
      continue;
    }
    pr_pack((char *)packet, cc, &from);
    if (npackets && nreceived >= npackets)
      break;
  }
  finish(0);
  /* NOTREACHED */
  return 0;
}

/*
 * catcher --
 *  This routine causes another PING to be transmitted, and then
 * schedules another SIGALRM for 1 second from now.
 * 
 * bug --
 *  Our sense of time will slowly skew (i.e., packets will not be
 * launched exactly at 1-second intervals).  This does not affect the
 * quality of the delay and loss statistics.
 */
static void
catcher(int ignore)
{
  int waittime;

  (void)ignore;
  pinger();
  (void)signal(SIGALRM, catcher);
  if (!npackets || ntransmitted < npackets)
    alarm((u_int)interval);
  else {
    if (nreceived) {
      waittime = 2 * tmax / 1000;
      if (!waittime)
        waittime = 1;
      if (waittime > MAXWAIT)
        waittime = MAXWAIT;
    } else
      waittime = MAXWAIT;
    (void)signal(SIGALRM, finish);
    (void)alarm((u_int)waittime);
  }
}

#if !defined(__GLIBC__) || (__GLIBC__ < 2)
#define icmp_type type
#define icmp_code code
#define icmp_cksum checksum
#define icmp_id un.echo.id
#define icmp_seq un.echo.sequence
#define icmp_gwaddr un.gateway
#endif /* __GLIBC__ */

#define ip_hl ihl
#define ip_v version
#define ip_tos tos
#define ip_len tot_len
#define ip_id id
#define ip_off frag_off
#define ip_ttl ttl
#define ip_p protocol
#define ip_sum check
#define ip_src saddr
#define ip_dst daddr

/*
 * pinger --
 *   Compose and transmit an ICMP ECHO REQUEST packet.  The IP packet
 * will be added on by the kernel.  The ID field is our UNIX process ID,
 * and the sequence number is an ascending integer.  The first 8 bytes
 * of the data portion are used to hold a UNIX "timeval" struct in VAX
 * byte-order, to compute the round-trip time.
 */
static void
pinger(void)
{
  register struct icmphdr *icp;
  register int cc;
  int i;

  icp = (struct icmphdr *)outpack;
  icp->icmp_type = ICMP_ECHO;
  icp->icmp_code = 0;
  icp->icmp_cksum = 0;
  icp->icmp_seq = ntransmitted++;
  icp->icmp_id = ident;      /* ID */

  CLR(icp->icmp_seq % mx_dup_ck);

  if (timing)
    (void)gettimeofday((struct timeval *)&outpack[8],
        (struct timezone *)NULL);

  cc = datalen + 8;      /* skips ICMP portion */

  /* compute ICMP checksum here */
  icp->icmp_cksum = in_cksum((u_short *)icp, cc);

  i = sendto(s, (char *)outpack, cc, 0, &whereto,
      sizeof(struct sockaddr));

  if (i < 0 || i != cc)  {
    if (i < 0)
      perror("ping: sendto");
    (void)printf("ping: wrote %s %d chars, ret=%d\n",
        hostname, cc, i);
  }
  if (!(options & F_QUIET) && options & F_FLOOD)
    (void)write(STDOUT_FILENO, &DOT, 1);
}

/*
 * pr_pack --
 *  Print out the packet, if it came from us.  This logic is necessary
 * because ALL readers of the ICMP socket get a copy of ALL ICMP packets
 * which arrive ('tis only fair).  This permits multiple copies of this
 * program to be run without having intermingled output (or statistics!).
 */
void
pr_pack(char *buf, int cc, struct sockaddr_in *from)
{
  register struct icmphdr *icp;
  register int i;
  register u_char *cp,*dp;
/*#if 0*/
  register u_long l;
  register int j;
  static int old_rrlen;
  static char old_rr[MAX_IPOPTLEN];
/*#endif*/
  struct iphdr *ip;
  struct timeval tv, *tp;
  long triptime = 0;
  int hlen, dupflag;

  (void)gettimeofday(&tv, (struct timezone *)NULL);

  /* Check the IP header */
  ip = (struct iphdr *)buf;
  hlen = ip->ip_hl << 2;
  if (cc < datalen + ICMP_MINLEN) {
    if (options & F_VERBOSE)
      (void)fprintf(stderr,
        "ping: packet too short (%d bytes) from %s\n", cc,
        inet_ntoa(*(struct in_addr *)&from->sin_addr.s_addr));
    return;
  }

  /* Now the ICMP part */
  cc -= hlen;
  icp = (struct icmphdr *)(buf + hlen);
  if (icp->icmp_type == ICMP_ECHOREPLY) {
    if (icp->icmp_id != ident)
      return;      /* 'Twas not our ECHO */
    ++nreceived;
    if (timing) {
#ifndef icmp_data
      tp = (struct timeval *)(icp + 1);
#else
      tp = (struct timeval *)icp->icmp_data;
#endif
      tvsub(&tv, tp);
      triptime = tv.tv_sec * 10000 + (tv.tv_usec / 100);
      tsum += triptime;
      if (triptime < tmin)
        tmin = triptime;
      if (triptime > tmax)
        tmax = triptime;
    }

    if (TST(icp->icmp_seq % mx_dup_ck)) {
      ++nrepeats;
      --nreceived;
      dupflag = 1;
    } else {
      SET(icp->icmp_seq % mx_dup_ck);
      dupflag = 0;
    }

    if (options & F_QUIET)
      return;

    if (options & F_FLOOD)
      (void)write(STDOUT_FILENO, &BSPACE, 1);
    else {
      (void)printf("%d bytes from %s: icmp_seq=%u", cc,
         inet_ntoa(*(struct in_addr *)&from->sin_addr.s_addr),
         icp->icmp_seq);
      (void)printf(" ttl=%d", ip->ip_ttl);
      if (timing)
        (void)printf(" time=%ld.%ld ms", triptime/10,
            triptime%10);
      if (dupflag)
        (void)printf(" (DUP!)");
      /* check the data */
#ifndef icmp_data
      cp = ((u_char*)(icp + 1) + 8);
#else
      cp = (u_char*)icp->icmp_data + 8;
#endif
      dp = &outpack[8 + sizeof(struct timeval)];
      for (i = 8; i < datalen; ++i, ++cp, ++dp) {
        if (*cp != *dp) {
  (void)printf("\nwrong data byte #%d should be 0x%x but was 0x%x",
      i, *dp, *cp);
          cp = (u_char*)(icp + 1);
          for (i = 8; i < datalen; ++i, ++cp) {
            if ((i % 32) == 8)
              (void)printf("\n\t");
            (void)printf("%x ", *cp);
          }
          break;
        }
      }
    }
  } else {
    /* We've got something other than an ECHOREPLY */
    if (!(options & F_VERBOSE))
      return;
    (void)printf("%d bytes from %s: ", cc,
        pr_addr(from->sin_addr.s_addr));
    pr_icmph(icp);
  }

/*#if 0*/
  /* Display any IP options */
  cp = (u_char *)buf + sizeof(struct iphdr);

  for (; hlen > (int)sizeof(struct iphdr); --hlen, ++cp)
    switch (*cp) {
    case IPOPT_EOL:
      hlen = 0;
      break;
    case IPOPT_LSRR:
      (void)printf("\nLSRR: ");
      hlen -= 2;
      j = *++cp;
      ++cp;
      if (j > IPOPT_MINOFF)
        for (;;) {
          l = *++cp;
          l = (l<<8) + *++cp;
          l = (l<<8) + *++cp;
          l = (l<<8) + *++cp;
          if (l == 0)
            (void)printf("\t0.0.0.0");
        else
          (void)printf("\t%s", pr_addr(ntohl(l)));
        hlen -= 4;
        j -= 4;
        if (j <= IPOPT_MINOFF)
          break;
        (void)putchar('\n');
      }
      break;
    case IPOPT_RR:
      j = *++cp;    /* get length */
      i = *++cp;    /* and pointer */
      hlen -= 2;
      if (i > j)
        i = j;
      i -= IPOPT_MINOFF;
      if (i <= 0)
        continue;
      if (i == old_rrlen
          && cp == (u_char *)buf + sizeof(struct iphdr) + 2
          && !memcmp((char *)cp, old_rr, i)
          && !(options & F_FLOOD)) {
        (void)printf("\t(same route)");
        i = ((i + 3) / 4) * 4;
        hlen -= i;
        cp += i;
        break;
      }
      old_rrlen = i;
      memcpy(old_rr, cp, i);
      (void)printf("\nRR: ");
      for (;;) {
        l = *++cp;
        l = (l<<8) + *++cp;
        l = (l<<8) + *++cp;
        l = (l<<8) + *++cp;
        if (l == 0)
          (void)printf("\t0.0.0.0");
        else
          (void)printf("\t%s", pr_addr(ntohl(l)));
        hlen -= 4;
        i -= 4;
        if (i <= 0)
          break;
        (void)putchar('\n');
      }
      break;
    case IPOPT_NOP:
      (void)printf("\nNOP");
      break;
    default:
      (void)printf("\nunknown option %x", *cp);
      break;
    }
/*#endif*/
  if (!(options & F_FLOOD)) {
    (void)putchar('\n');
    (void)fflush(stdout);
  }
}

/*
 * in_cksum --
 *  Checksum routine for Internet Protocol family headers (C Version)
 */
static int
in_cksum(u_short *addr, int len)
{
  register int nleft = len;
  register u_short *w = addr;
  register int sum = 0;
  u_short answer = 0;

  /*
   * Our algorithm is simple, using a 32 bit accumulator (sum), we add
   * sequential 16 bit words to it, and at the end, fold back all the
   * carry bits from the top 16 bits into the lower 16 bits.
   */
  while (nleft > 1)  {
    sum += *w++;
    nleft -= 2;
  }

  /* mop up an odd byte, if necessary */
  if (nleft == 1) {
    *(u_char *)(&answer) = *(u_char *)w ;
    sum += answer;
  }

  /* add back carry outs from top 16 bits to low 16 bits */
  sum = (sum >> 16) + (sum & 0xffff);  /* add hi 16 to low 16 */
  sum += (sum >> 16);      /* add carry */
  answer = ~sum;        /* truncate to 16 bits */
  return(answer);
}

/*
 * tvsub --
 *  Subtract 2 timeval structs:  out = out - in.  Out is assumed to
 * be >= in.
 */
static void
tvsub(register struct timeval *out, register struct timeval *in)
{
  if ((out->tv_usec -= in->tv_usec) < 0) {
    --out->tv_sec;
    out->tv_usec += 1000000;
  }
  out->tv_sec -= in->tv_sec;
}

/*
 * finish --
 *  Print out statistics, and give up.
 */
static void
finish(int ignore)
{
  (void)ignore;

  (void)signal(SIGINT, SIG_IGN);
  (void)putchar('\n');
  (void)fflush(stdout);
  (void)printf("--- %s ping statistics ---\n", hostname);
  (void)printf("%ld packets transmitted, ", ntransmitted);
  (void)printf("%ld packets received, ", nreceived);
  if (nrepeats)
    (void)printf("+%ld duplicates, ", nrepeats);
  if (ntransmitted)
    if (nreceived > ntransmitted)
      (void)printf("-- somebody's printing up packets!");
    else
      (void)printf("%d%% packet loss",
          (int) (((ntransmitted - nreceived) * 100) /
          ntransmitted));
  (void)putchar('\n');
  if (nreceived && timing)
    (void)printf("round-trip min/avg/max = %ld.%ld/%lu.%ld/%ld.%ld ms\n",
      tmin/10, tmin%10,
      (tsum / (nreceived + nrepeats))/10,
      (tsum / (nreceived + nrepeats))%10,
      tmax/10, tmax%10);

  if (nreceived==0) exit(1);
  exit(0);
}

#ifdef notdef
static char *ttab[] = {
  "Echo Reply",    /* ip + seq + udata */
  "Dest Unreachable",  /* net, host, proto, port, frag, sr + IP */
  "Source Quench",  /* IP */
  "Redirect",    /* redirect type, gateway, + IP  */
  "Echo",
  "Time Exceeded",  /* transit, frag reassem + IP */
  "Parameter Problem",  /* pointer + IP */
  "Timestamp",    /* id + seq + three timestamps */
  "Timestamp Reply",  /* " */
  "Info Request",    /* id + sq */
  "Info Reply"    /* " */
};
#endif

/*
 * pr_icmph --
 *  Print a descriptive string about an ICMP header.
 */
static void
pr_icmph(struct icmphdr *icp)
{
  switch(icp->icmp_type) {
  case ICMP_ECHOREPLY:
    (void)printf("Echo Reply\n");
    /* XXX ID + Seq + Data */
    break;
  case ICMP_DEST_UNREACH:
    switch(icp->icmp_code) {
    case ICMP_NET_UNREACH:
      (void)printf("Destination Net Unreachable\n");
      break;
    case ICMP_HOST_UNREACH:
      (void)printf("Destination Host Unreachable\n");
      break;
    case ICMP_PROT_UNREACH:
      (void)printf("Destination Protocol Unreachable\n");
      break;
    case ICMP_PORT_UNREACH:
      (void)printf("Destination Port Unreachable\n");
      break;
    case ICMP_FRAG_NEEDED:
      (void)printf("frag needed and DF set\n");
      break;
    case ICMP_SR_FAILED:
      (void)printf("Source Route Failed\n");
      break;
    case ICMP_NET_UNKNOWN:
      (void)printf("Network Unknown\n");
      break;
    case ICMP_HOST_UNKNOWN:
      (void)printf("Host Unknown\n");
      break;
    case ICMP_HOST_ISOLATED:
      (void)printf("Host Isolated\n");
      break;
    case ICMP_NET_UNR_TOS:
      printf("Destination Network Unreachable At This TOS\n");
      break;
    case ICMP_HOST_UNR_TOS:
      printf("Destination Host Unreachable At This TOS\n");
      break;
#ifdef ICMP_PKT_FILTERED
    case ICMP_PKT_FILTERED:
      (void)printf("Packet Filtered\n");
      break;
#endif
#ifdef ICMP_PREC_VIOLATION
    case ICMP_PREC_VIOLATION:
      (void)printf("Precedence Violation\n");
      break;
#endif
#ifdef ICMP_PREC_CUTOFF
    case ICMP_PREC_CUTOFF:
      (void)printf("Precedence Cutoff\n");
      break;
#endif
    default:
      (void)printf("Dest Unreachable, Unknown Code: %d\n",
          icp->icmp_code);
      break;
    }
    /* Print returned IP header information */
#ifndef icmp_data
    pr_retip((struct iphdr *)(icp + 1));
#else
    pr_retip((struct iphdr *)icp->icmp_data);
#endif
    break;
  case ICMP_SOURCE_QUENCH:
    (void)printf("Source Quench\n");
#ifndef icmp_data
    pr_retip((struct iphdr *)(icp + 1));
#else
    pr_retip((struct iphdr *)icp->icmp_data);
#endif
    break;
  case ICMP_REDIRECT:
    switch(icp->icmp_code) {
    case ICMP_REDIR_NET:
      (void)printf("Redirect Network");
      break;
    case ICMP_REDIR_HOST:
      (void)printf("Redirect Host");
      break;
    case ICMP_REDIR_NETTOS:
      (void)printf("Redirect Type of Service and Network");
      break;
    case ICMP_REDIR_HOSTTOS:
      (void)printf("Redirect Type of Service and Host");
      break;
    default:
      (void)printf("Redirect, Bad Code: %d", icp->icmp_code);
      break;
    }
    (void)printf("(New addr: %s)\n", 
           inet_ntoa(icp->icmp_gwaddr));
#ifndef icmp_data
    pr_retip((struct iphdr *)(icp + 1));
#else
    pr_retip((struct iphdr *)icp->icmp_data);
#endif
    break;
  case ICMP_ECHO:
    (void)printf("Echo Request\n");
    /* XXX ID + Seq + Data */
    break;
  case ICMP_TIME_EXCEEDED:
    switch(icp->icmp_code) {
    case ICMP_EXC_TTL:
      (void)printf("Time to live exceeded\n");
      break;
    case ICMP_EXC_FRAGTIME:
      (void)printf("Frag reassembly time exceeded\n");
      break;
    default:
      (void)printf("Time exceeded, Bad Code: %d\n",
          icp->icmp_code);
      break;
    }
#ifndef icmp_data
    pr_retip((struct iphdr *)(icp + 1));
#else
    pr_retip((struct iphdr *)icp->icmp_data);
#endif
    break;
  case ICMP_PARAMETERPROB:
    (void)printf("Parameter problem: IP address = %s\n",
      inet_ntoa (icp->icmp_gwaddr));
#ifndef icmp_data
    pr_retip((struct iphdr *)(icp + 1));
#else
    pr_retip((struct iphdr *)icp->icmp_data);
#endif
    break;
  case ICMP_TIMESTAMP:
    (void)printf("Timestamp\n");
    /* XXX ID + Seq + 3 timestamps */
    break;
  case ICMP_TIMESTAMPREPLY:
    (void)printf("Timestamp Reply\n");
    /* XXX ID + Seq + 3 timestamps */
    break;
  case ICMP_INFO_REQUEST:
    (void)printf("Information Request\n");
    /* XXX ID + Seq */
    break;
  case ICMP_INFO_REPLY:
    (void)printf("Information Reply\n");
    /* XXX ID + Seq */
    break;
#ifdef ICMP_MASKREQ
  case ICMP_MASKREQ:
    (void)printf("Address Mask Request\n");
    break;
#endif
#ifdef ICMP_MASKREPLY
  case ICMP_MASKREPLY:
    (void)printf("Address Mask Reply\n");
    break;
#endif
  default:
    (void)printf("Bad ICMP type: %d\n", icp->icmp_type);
  }
}

/*
 * pr_iph --
 *  Print an IP header with options.
 */
static void
pr_iph(struct iphdr *ip)
{
  int hlen;
  u_char *cp;

  hlen = ip->ip_hl << 2;
  cp = (u_char *)ip + 20;    /* point to options */

  (void)printf("Vr HL TOS  Len   ID Flg  off TTL Pro  cks      Src      Dst Data\n");
  (void)printf(" %1x  %1x  %02x %04x %04x",
      ip->ip_v, ip->ip_hl, ip->ip_tos, ip->ip_len, ip->ip_id);
  (void)printf("   %1x %04x", ((ip->ip_off) & 0xe000) >> 13,
      (ip->ip_off) & 0x1fff);
  (void)printf("  %02x  %02x %04x", ip->ip_ttl, ip->ip_p, ip->ip_sum);
  (void)printf(" %s ", inet_ntoa(*((struct in_addr *) &ip->ip_src)));
  (void)printf(" %s ", inet_ntoa(*((struct in_addr *) &ip->ip_dst)));
  /* dump and option bytes */
  while (hlen-- > 20) {
    (void)printf("%02x", *cp++);
  }
  (void)putchar('\n');
}

/*
 * pr_addr --
 *  Return an ascii host address as a dotted quad and optionally with
 * a hostname.
 */
static char *
pr_addr(u_long l)
{
  struct hostent *hp;
  static char buf[256];

  if ((options & F_NUMERIC) ||
      !(hp = gethostbyaddr((char *)&l, 4, AF_INET)))
    (void)snprintf(buf, sizeof(buf), "%s", 
             inet_ntoa(*(struct in_addr *)&l));
  else
    (void)snprintf(buf, sizeof(buf), "%s (%s)", hp->h_name,
        inet_ntoa(*(struct in_addr *)&l));
  return(buf);
}

/*
 * pr_retip --
 *  Dump some info on a returned (via ICMP) IP packet.
 */
static void
pr_retip(struct iphdr *ip)
{
  int hlen;
  u_char *cp;

  pr_iph(ip);
  hlen = ip->ip_hl << 2;
  cp = (u_char *)ip + hlen;

  if (ip->ip_p == 6)
    (void)printf("TCP: from port %u, to port %u (decimal)\n",
        (*cp * 256 + *(cp + 1)), (*(cp + 2) * 256 + *(cp + 3)));
  else if (ip->ip_p == 17)
    (void)printf("UDP: from port %u, to port %u (decimal)\n",
      (*cp * 256 + *(cp + 1)), (*(cp + 2) * 256 + *(cp + 3)));
}

static void
fill(void *bp1, char *patp)
{
  register int ii, jj, kk;
  int pat[16];
  char *cp, *bp = (char *)bp1;

  for (cp = patp; *cp; cp++)
    if (!isxdigit(*cp)) {
      (void)fprintf(stderr,
          "ping: patterns must be specified as hex digits.\n");
      exit(2);
    }
  ii = sscanf(patp,
      "%2x%2x%2x%2x%2x%2x%2x%2x%2x%2x%2x%2x%2x%2x%2x%2x",
      &pat[0], &pat[1], &pat[2], &pat[3], &pat[4], &pat[5], &pat[6],
      &pat[7], &pat[8], &pat[9], &pat[10], &pat[11], &pat[12],
      &pat[13], &pat[14], &pat[15]);

  if (ii > 0)
    for (kk = 0; kk <= MAXPACKET - (8 + ii); kk += ii)
      for (jj = 0; jj < ii; ++jj)
        bp[jj + kk] = pat[jj];
  if (!(options & F_QUIET)) {
    (void)printf("PATTERN: 0x");
    for (jj = 0; jj < ii; ++jj)
      (void)printf("%02x", bp[jj] & 0xFF);
    (void)printf("\n");
  }
}

static void
usage(void)
{
  (void)fprintf(stderr,
      "usage: ping [-LRdfnqrv] [-c count] [-i wait] [-l preload]\n\t[-p pattern] [-s packetsize] [-t ttl] [-I interface address] host\n");
  exit(2);
}