/*
 * icmpquery.c - send and receive ICMP queries for address mask
 *               and current time.
 *
 * Version 1.0
 *
 * Copyright 1998, 1998 David G. Andersen <angio@pobox.com>
 *                                        <danderse@cs.utah.edu>
 *                                        http://www.angio.net/
 *
 * Verified to work on:
 *    FreeBSD (2.x, 3.x)
 *    Linux 2.0.x
 *    NetBSD 1.3
 *
 * Should work on Solaris and other platforms with BSD-ish stacks.
 *
 * If you compile it somewhere else, or it doesn't work somewhere,
 * please let me know.
 *
 * Compilation:  gcc icmpquery.c -o icmpquery
 */


/* Some portions of this code are taken from FreeBSD's ping source.
 * Those portions are subject to the BSD copyright, which is appended
 * at the end of this file.
 */

#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))

#include <time.h>
#include <sys/time.h>
#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>
#include <errno.h>
#include <string.h>
#include <signal.h>

/*
 * We perform lookups on the hosts, and then store them in a chain
 * here.
 *
 * Yes, it's linear.  No, I don't care.
 */

struct hostdesc {
  char *hostname;
  struct in_addr hostaddr;
  struct hostdesc *next;
};

struct hostdesc *hostnames;
struct hostdesc *hosttail;

void resolv_from(char *hostfrom, struct in_addr *fromaddr)
{
  struct hostent *hp;
  if (hostfrom == NULL) {
    fromaddr->s_addr = 0;
    return;
  }
  
  if ((hp = gethostbyname(hostfrom)) == NULL) {
    if ((fromaddr->s_addr = inet_addr(hostfrom)) == -1) {
      fprintf(stderr, "could not resolve from address\n");
      exit(0);
    }
  } else {
    bcopy(hp->h_addr_list[0], &fromaddr->s_addr, hp->h_length);
  }
}

/*
 * Set up the list of hosts.  Return the count.
 */

int makehosts(char **hostlist)
{
  int i;
  struct hostent *hp;
  struct in_addr tmpaddr;
  int hostcount = 0;
  
  for (i = 0; hostlist[i]; i++) {
#ifdef DEBUG
    printf("Resolving %s\n", hostlist[i]);
#endif
    if ((hp = gethostbyname(hostlist[i])) == NULL) {
      if (tmpaddr.s_addr = inet_addr(hostlist[i])) {
        /* Could not resolve it.  Skip it. */
        fprintf(stderr, "%s: unknown host\n",
          hostlist[i]);
        continue;
      }
    } else {
      bcopy(hp->h_addr_list[0],
            &tmpaddr.s_addr, hp->h_length);
    }

    /* The host has been resolved.  Put it in the chain */
    /* We want to stick it on the end. */
    if (hostnames == NULL) {
      hostnames = (struct hostdesc *)
        malloc(sizeof(*hostnames));
      if (hostnames == NULL) {
        perror("hostnames malloc failed");
        exit(-1);
      }
      hosttail = hostnames;
    } else {
      hosttail->next = (struct hostdesc *)
        malloc(sizeof(*hostnames));
      if (hosttail->next == NULL) {
        perror("hosttail->next malloc failed");
        exit(-1);
      }
      hosttail = hosttail->next;
    }
    hosttail->hostname = strdup(hostlist[i]);
    if (hosttail->hostname == NULL) {
      perror("strdup failed");
      exit(-1);
    }
    hosttail->hostaddr = tmpaddr;
    hosttail->next = NULL;
    hostcount++;
  }
  return hostcount;
}

void usage(char *prog)
{
   fprintf(stderr,
     "%s  <-querytype> [-f fromhost] [-d delay] [-T time] destination list\n"
     "    where <querytype> is one of:\n"
     "        -t : icmp timestamp request\n"
     "        -m : icmp address mask request\n"
     "    The delay is in microseconds to sleep between packets.\n"
     "    The destination list is a list of hostnames or addresses\n"
     "    -T specifies the number of seconds to wait for a host to\n"
     "       respond.  The default is 5.\n"
     "    If you're on a modem, you may wish to use a larger -d and -T\n"
     , prog);
}

/*
 * Set up a packet.  Returns the length of the ICMP portion.
 */

int initpacket(char *buf, int querytype, struct in_addr fromaddr)
{
   struct ip *ip = (struct ip *)buf;
   struct icmp *icmp = (struct icmp *)(ip + 1);
   int on = 1;

   /* things we customize */
   int icmplen = 0;
   int icmptype = 0;

   int offset;
   int typevar;
   int subtype;

   ip->ip_src = fromaddr;  /* if 0,  have kernel fill in */
   ip->ip_v = 4;    /* Always use ipv4 for now */
   ip->ip_hl = sizeof *ip >> 2;
   ip->ip_tos = 0;
   ip->ip_id = htons(4321);
   ip->ip_ttl = 255;
   ip->ip_p = 1;
   ip->ip_sum = 0;                 /* kernel fills in */

   icmp->icmp_seq = 1;
   icmp->icmp_cksum = 0;
   icmp->icmp_type = querytype;
   icmp->icmp_code = 0;

   switch(querytype) {
   case ICMP_TSTAMP:
     gettimeofday( (struct timeval *)(icmp+8), NULL);
     bzero( icmp+12, 8);
     icmplen = 20;
     break;
   case ICMP_MASKREQ:
     *((char *)(icmp+8)) = 255;
     icmplen = 12;
     break;
   default:
     fprintf(stderr, "eek: unknown query type\n");
     exit(0);
   }
   ip->ip_len = sizeof(struct ip) + icmplen;
   return icmplen;
}
   
void sendpings(int s, int querytype, struct hostdesc *head, int delay,
         struct in_addr fromaddr)
     
{
  char buf[1500];
  struct ip *ip = (struct ip *)buf;
  struct icmp *icmp = (struct icmp *)(ip + 1);
  struct sockaddr_in dst;
  int icmplen;

  bzero(buf, 1500);
  icmplen = initpacket(buf, querytype, fromaddr);
  dst.sin_family = AF_INET;

  while (head != NULL) {
#ifdef DEBUG
    printf("pinging %s\n", head->hostname);
#endif
    ip->ip_dst.s_addr = head->hostaddr.s_addr;
    dst.sin_addr = head->hostaddr;
    icmp->icmp_cksum = 0;
    icmp->icmp_cksum = in_cksum(icmp, icmplen);
    if (sendto(s, buf, ip->ip_len, 0,
         (struct sockaddr *)&dst,
         sizeof(dst)) < 0) {
      perror("sendto");
    }
    if (delay)
      usleep(delay);
    /* Don't flood the pipeline..kind of arbitrary */
    head = head->next;
  }
}

void myexit(int whatsig)
{
  exit(0);
}

/*
 * Listen for 'hostcount' pings, print out the information, and
 * then exit.
 */

void recvpings(int s, int querytype, struct hostdesc *head, int hostcount)
{
  char buf[1500];
  struct ip *ip = (struct ip *)buf;
  struct icmp *icmp;
  int err = 0;
  long int fromlen = 0;
  int hlen;
  struct timeval *tp;
  struct timeval tv;
  int recvd = 0;
  char *hostto;
  char hostbuf[128];  /* We'll print the address here otherwise */
  struct hostdesc *foundhost;

  gettimeofday(&tv, NULL);

  while (recvd < hostcount) {
    if ((err = recvfrom(s, buf, sizeof buf, 0, NULL,
            (int *)&fromlen)) < 0)
    {
      perror("icmpquery:  recvfrom");
    }
      
    hlen = ip->ip_hl << 2;
    icmp = (struct icmp *)(buf + hlen);

    /* Find the host */
    hostto = 0;
    for (foundhost = head; foundhost != NULL;
         foundhost = foundhost->next) {
      if (foundhost->hostaddr.s_addr == ip->ip_src.s_addr) {
        hostto = foundhost->hostname;
        break;
      }
    }

    if (!hostto) {
      sprintf(hostbuf, "unknown (%s)",
        inet_ntoa(ip->ip_src));
      hostto = hostbuf;
    }
    
    /* For time */
    switch(icmp->icmp_type) {
    case ICMP_TSTAMPREPLY:
      fromlen = ntohl(icmp->icmp_ttime);
       /* ms since midnight. yuch. */
      tv.tv_usec = fromlen;
      tv.tv_usec = 0;
      tv.tv_sec -= tv.tv_sec%(24*60*60);
      tv.tv_sec += (fromlen/1000);
      tv.tv_usec = (fromlen%1000);
      printf("%-40.40s:  %s", hostto, ctime(&(tv.tv_sec)));
      break;

    case ICMP_MASKREPLY:
      fromlen = ntohl(icmp->icmp_dun.id_mask);
      printf("%-40.40s:  0x%lX\n", hostto, fromlen);
      break;

    default:
      printf("Unknown ICMP message received (type %d)\n",
             icmp->icmp_type);
    }
    recvd++;
  }
}

int
main(int argc, char **argv)
{
   int s;

   char *progname;
   extern char *optarg;         /* getopt variable declarations */
   char *hostfrom = NULL;
   extern int optind;
   extern int optopt;
   extern int opterr;
   char ch;                     /* Holds the getopt result */
   int on = 1;
   int hostcount;
   int delay = 0;
   int querytype = ICMP_TSTAMP;
   struct in_addr fromaddr;
   int timeout = 5;  /* Default to 5 seconds */

   fromaddr.s_addr = 0;

   progname = argv[0];

   while ((ch = getopt(argc, argv, "tmf:d:T:")) != EOF) 
      switch(ch)
      {
      case 'd':
        delay = (int) strtol(optarg, NULL, 10);
        break;
      case 't': /* timestamp request */
        querytype = ICMP_TSTAMP;
        break;
      case 'm': /* address mask request */
        querytype = ICMP_MASKREQ;
        break;
      case 'f':
        hostfrom = optarg;
        resolv_from(hostfrom, &fromaddr);
        break;
      case 'T':
        timeout = (int) strtol(optarg, NULL, 10);
        break;
      default:
        usage(progname);
        exit(-1);
      }
   argc -= optind;
   argv += optind;

   if (!argv[0] || !strlen(argv[0])) 
   {
      usage(progname);
      exit(-1);
   }

   hostcount = makehosts(argv);

   if ((s = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP)) < 0) {
      perror("socket");
      exit(1);
   }
   if (setsockopt(s, IPPROTO_IP, IP_HDRINCL, &on, sizeof(on)) < 0) {
      perror("IP_HDRINCL");
      exit(1);
   }

   signal(SIGALRM, myexit);
   alarm(timeout);
   sendpings(s, querytype, hostnames, delay, fromaddr);
   recvpings(s, querytype, hostnames, hostcount);
}
   
/*
 * in_cksum --
 *  Checksum routine for Internet Protocol family headers (C Version)
 *      From FreeBSD's ping.c
 */

in_cksum(addr, len)
  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);
}


/*
 * Copyright (c) 1989, 1993
 *      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.
 */