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check_icmp.c

 /******************************************************************************
*
* Nagios check_icmp plugin
*
* License: GPL
* Copyright (c) 2005-2006 nagios-plugins team
*
* Original Author : Andreas Ericsson <ae@op5.se>
*
* Last Modified: $Date: 2006/10/24 21:54:06 $
*
* Description:
*
* This file contains the check_icmp plugin
*
*  Relevant RFC's: 792 (ICMP), 791 (IP)
*
*  This program was modeled somewhat after the check_icmp program,
*  which was in turn a hack of fping (www.fping.org) but has been
*  completely rewritten since to generate higher precision rta values,
*  and support several different modes as well as setting ttl to control.
*  redundant routes. The only remainders of fping is currently a few
*  function names.
*
* License Information:
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* $Id: check_icmp.c,v 1.8 2006/10/24 21:54:06 opensides Exp $
* 
*****************************************************************************/

/* progname may change */
/* char *progname = "check_icmp"; */
char *progname;
const char *revision = "$Revision: 1.8 $";
const char *copyright = "2005-2006";
const char *email = "nagiosplug-devel@lists.sourceforge.net";

/** nagios plugins basic includes */
#include "common.h"
#include "netutils.h"
#include "utils.h"

#include <sys/time.h>
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <unistd.h>
#include <stddef.h>
#include <errno.h>
#include <string.h>
#include <ctype.h>
#include <netdb.h>
#include <sys/socket.h>
#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <arpa/inet.h>
#include <signal.h>


/** sometimes undefined system macros (quite a few, actually) **/
#ifndef MAXTTL
# define MAXTTL   255
#endif
#ifndef INADDR_NONE
# define INADDR_NONE 0xffffffU
#endif

#ifndef SOL_IP
#define SOL_IP 0
#endif

/* we bundle these in one #ifndef, since they're all from BSD
 * Put individual #ifndef's around those that bother you */
#ifndef ICMP_UNREACH_NET_UNKNOWN
# define ICMP_UNREACH_NET_UNKNOWN 6
# define ICMP_UNREACH_HOST_UNKNOWN 7
# define ICMP_UNREACH_ISOLATED 8
# define ICMP_UNREACH_NET_PROHIB 9
# define ICMP_UNREACH_HOST_PROHIB 10
# define ICMP_UNREACH_TOSNET 11
# define ICMP_UNREACH_TOSHOST 12
#endif
/* tru64 has the ones above, but not these */
#ifndef ICMP_UNREACH_FILTER_PROHIB
# define ICMP_UNREACH_FILTER_PROHIB 13
# define ICMP_UNREACH_HOST_PRECEDENCE 14
# define ICMP_UNREACH_PRECEDENCE_CUTOFF 15
#endif


typedef unsigned short range_t;  /* type for get_range() -- unimplemented */

typedef struct rta_host {
      unsigned short id;           /* id in **table, and icmp pkts */
      char *name;                  /* arg used for adding this host */
      char *msg;                   /* icmp error message, if any */
      struct sockaddr_in saddr_in; /* the address of this host */
      struct in_addr error_addr;   /* stores address of error replies */
      unsigned long long time_waited; /* total time waited, in usecs */
      unsigned int icmp_sent, icmp_recv, icmp_lost; /* counters */
      unsigned char icmp_type, icmp_code; /* type and code from errors */
      unsigned short flags;        /* control/status flags */
      double rta;                  /* measured RTA */
      unsigned char pl;            /* measured packet loss */
      struct rta_host *next;       /* linked list */
} rta_host;

#define FLAG_LOST_CAUSE 0x01  /* decidedly dead target. */

/* threshold structure. all values are maximum allowed, exclusive */
typedef struct threshold {
      unsigned char pl;    /* max allowed packet loss in percent */
      unsigned int rta;  /* roundtrip time average, microseconds */
} threshold;

/* the data structure */
typedef struct icmp_ping_data {
      struct timeval stime;   /* timestamp (saved in protocol struct as well) */
      unsigned short ping_id;
} icmp_ping_data;

/* the different modes of this program are as follows:
 * MODE_RTA: send all packets no matter what (mimic check_icmp and check_ping)
 * MODE_HOSTCHECK: Return immediately upon any sign of life
 *                 In addition, sends packets to ALL addresses assigned
 *                 to this host (as returned by gethostbyname() or
 *                 gethostbyaddr() and expects one host only to be checked at
 *                 a time.  Therefore, any packet response what so ever will
 *                 count as a sign of life, even when received outside
 *                 crit.rta limit. Do not misspell any additional IP's.
 * MODE_ALL:  Requires packets from ALL requested IP to return OK (default).
 * MODE_ICMP: implement something similar to check_icmp (MODE_RTA without
 *            tcp and udp args does this)
 */
#define MODE_RTA 0
#define MODE_HOSTCHECK 1
#define MODE_ALL 2
#define MODE_ICMP 3

/* the different ping types we can do
 * TODO: investigate ARP ping as well */
#define HAVE_ICMP 1
#define HAVE_UDP 2
#define HAVE_TCP 4
#define HAVE_ARP 8

#define MIN_PING_DATA_SIZE sizeof(struct icmp_ping_data)
#define MAX_IP_PKT_SIZE 65536 /* (theoretical) max IP packet size */
#define IP_HDR_SIZE 20
#define MAX_PING_DATA (MAX_IP_PKT_SIZE - IP_HDR_SIZE - ICMP_MINLEN)
#define DEFAULT_PING_DATA_SIZE (MIN_PING_DATA_SIZE + 44)

/* various target states */
#define TSTATE_INACTIVE 0x01  /* don't ping this host anymore */
#define TSTATE_WAITING 0x02         /* unanswered packets on the wire */
#define TSTATE_ALIVE 0x04       /* target is alive (has answered something) */
#define TSTATE_UNREACH 0x08

/** prototypes **/
void print_help (void);
void print_usage (void);
static u_int get_timevar(const char *);
static u_int get_timevaldiff(struct timeval *, struct timeval *);
static int wait_for_reply(int, u_int);
static int recvfrom_wto(int, char *, unsigned int, struct sockaddr *, u_int *);
static int send_icmp_ping(int, struct rta_host *);
static int get_threshold(char *str, threshold *th);
static void run_checks(void);
static int add_target(char *);
static int add_target_ip(char *, struct in_addr *);
static int handle_random_icmp(struct icmp *, struct sockaddr_in *);
static unsigned short icmp_checksum(unsigned short *, int);
static void finish(int);
static void crash(const char *, ...);

/** external **/
extern int optind, opterr, optopt;
extern char *optarg;
extern char **environ;

/** global variables **/
static struct rta_host **table, *cursor, *list;
static threshold crit = {80, 500000}, warn = {40, 200000};
static int mode, protocols, sockets, debug = 0, timeout = 10;
static unsigned short icmp_pkt_size, icmp_data_size = DEFAULT_PING_DATA_SIZE;
static unsigned int icmp_sent = 0, icmp_recv = 0, icmp_lost = 0;
#define icmp_pkts_en_route (icmp_sent - (icmp_recv + icmp_lost))
static unsigned short targets_down = 0, targets = 0, packets = 0;
#define targets_alive (targets - targets_down)
static unsigned int retry_interval, pkt_interval, target_interval;
static int icmp_sock, tcp_sock, udp_sock, status = STATE_OK;
static pid_t pid;
static struct timezone tz;
static struct timeval prog_start;
static unsigned long long max_completion_time = 0;
static unsigned char ttl = 0; /* outgoing ttl */
static unsigned int warn_down = 1, crit_down = 1; /* host down threshold values */
float pkt_backoff_factor = 1.5;
float target_backoff_factor = 1.5;

/** code start **/
static void
crash(const char *fmt, ...)
{
      va_list ap;

      printf("%s: ", progname);

      va_start(ap, fmt);
      vprintf(fmt, ap);
      va_end(ap);

      if(errno) printf(": %s", strerror(errno));
      puts("");

      exit(3);
}


static char *
get_icmp_error_msg(unsigned char icmp_type, unsigned char icmp_code)
{
      char *msg = "unreachable";

      if(debug > 1) printf("get_icmp_error_msg(%u, %u)\n", icmp_type, icmp_code);
      switch(icmp_type) {
      case ICMP_UNREACH:
            switch(icmp_code) {
            case ICMP_UNREACH_NET: msg = "Net unreachable"; break;
            case ICMP_UNREACH_HOST: msg = "Host unreachable"; break;
            case ICMP_UNREACH_PROTOCOL: msg = "Protocol unreachable (firewall?)"; break;
            case ICMP_UNREACH_PORT: msg = "Port unreachable (firewall?)"; break;
            case ICMP_UNREACH_NEEDFRAG: msg = "Fragmentation needed"; break;
            case ICMP_UNREACH_SRCFAIL: msg = "Source route failed"; break;
            case ICMP_UNREACH_ISOLATED: msg = "Source host isolated"; break;
            case ICMP_UNREACH_NET_UNKNOWN: msg = "Unknown network"; break;
            case ICMP_UNREACH_HOST_UNKNOWN: msg = "Unknown host"; break;
            case ICMP_UNREACH_NET_PROHIB: msg = "Network denied (firewall?)"; break;
            case ICMP_UNREACH_HOST_PROHIB: msg = "Host denied (firewall?)"; break;
            case ICMP_UNREACH_TOSNET: msg = "Bad TOS for network (firewall?)"; break;
            case ICMP_UNREACH_TOSHOST: msg = "Bad TOS for host (firewall?)"; break;
            case ICMP_UNREACH_FILTER_PROHIB: msg = "Prohibited by filter (firewall)"; break;
            case ICMP_UNREACH_HOST_PRECEDENCE: msg = "Host precedence violation"; break;
            case ICMP_UNREACH_PRECEDENCE_CUTOFF: msg = "Precedence cutoff"; break;
            default: msg = "Invalid code"; break;
            }
            break;

      case ICMP_TIMXCEED:
            /* really 'out of reach', or non-existant host behind a router serving
             * two different subnets */
            switch(icmp_code) {
            case ICMP_TIMXCEED_INTRANS: msg = "Time to live exceeded in transit"; break;
            case ICMP_TIMXCEED_REASS: msg = "Fragment reassembly time exceeded"; break;
            default: msg = "Invalid code"; break;
            }
            break;

      case ICMP_SOURCEQUENCH: msg = "Transmitting too fast"; break;
      case ICMP_REDIRECT: msg = "Redirect (change route)"; break;
      case ICMP_PARAMPROB: msg = "Bad IP header (required option absent)"; break;

            /* the following aren't error messages, so ignore */
      case ICMP_TSTAMP:
      case ICMP_TSTAMPREPLY:
      case ICMP_IREQ:
      case ICMP_IREQREPLY:
      case ICMP_MASKREQ:
      case ICMP_MASKREPLY:
      default: msg = ""; break;
      }

      return msg;
}

static int
handle_random_icmp(struct icmp *p, struct sockaddr_in *addr)
{
      struct icmp *sent_icmp = NULL;
      struct rta_host *host = NULL;
      unsigned char *ptr;

      if(p->icmp_type == ICMP_ECHO && p->icmp_id == pid) {
            /* echo request from us to us (pinging localhost) */
            return 0;
      }

      ptr = (unsigned char *)p;
      if(debug) printf("handle_random_icmp(%p, %p)\n", (void *)p, (void *)addr);

      /* only handle a few types, since others can't possibly be replies to
       * us in a sane network (if it is anyway, it will be counted as lost
       * at summary time, but not as quickly as a proper response */
      /* TIMXCEED can be an unreach from a router with multiple IP's which
       * serves two different subnets on the same interface and a dead host
       * on one net is pinged from the other. The router will respond to
       * itself and thus set TTL=0 so as to not loop forever.  Even when
       * TIMXCEED actually sends a proper icmp response we will have passed
       * too many hops to have a hope of reaching it later, in which case it
       * indicates overconfidence in the network, poor routing or both. */
      if(p->icmp_type != ICMP_UNREACH && p->icmp_type != ICMP_TIMXCEED &&
         p->icmp_type != ICMP_SOURCEQUENCH && p->icmp_type != ICMP_PARAMPROB)
      {
            return 0;
      }

      /* might be for us. At least it holds the original package (according
       * to RFC 792). If it isn't, just ignore it */
      sent_icmp = (struct icmp *)(ptr + 28);
      if(sent_icmp->icmp_type != ICMP_ECHO || sent_icmp->icmp_id != pid ||
         sent_icmp->icmp_seq >= targets)
      {
            if(debug) printf("Packet is no response to a packet we sent\n");
            return 0;
      }

      /* it is indeed a response for us */
      host = table[sent_icmp->icmp_seq];
      if(debug) {
            printf("Received \"%s\" from %s for ICMP ECHO sent to %s.\n",
                     get_icmp_error_msg(p->icmp_type, p->icmp_code),
                     inet_ntoa(addr->sin_addr), host->name);
      }

      icmp_lost++;
      host->icmp_lost++;
      /* don't spend time on lost hosts any more */
      if(host->flags & FLAG_LOST_CAUSE) return 0;

      /* source quench means we're sending too fast, so increase the
       * interval and mark this packet lost */
      if(p->icmp_type == ICMP_SOURCEQUENCH) {
            pkt_interval *= pkt_backoff_factor;
            target_interval *= target_backoff_factor;
      }
      else {
            targets_down++;
            host->flags |= FLAG_LOST_CAUSE;
      }
      host->icmp_type = p->icmp_type;
      host->icmp_code = p->icmp_code;
      host->error_addr.s_addr = addr->sin_addr.s_addr;

      return 0;
}

int
main(int argc, char **argv)
{
      int i;
      char *ptr;
      long int arg;
      int icmp_sockerrno, udp_sockerrno, tcp_sockerrno;
      int result;
      struct rta_host *host;
      
      /* we only need to be setsuid when we get the sockets, so do
       * that before pointer magic (esp. on network data) */
      icmp_sockerrno = udp_sockerrno = tcp_sockerrno = sockets = 0;

      if((icmp_sock = socket(PF_INET, SOCK_RAW, IPPROTO_ICMP)) != -1)
            sockets |= HAVE_ICMP;
      else icmp_sockerrno = errno;

      /* if((udp_sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) != -1) */
      /*    sockets |= HAVE_UDP; */
      /* else udp_sockerrno = errno; */

      /* if((tcp_sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) != -1) */
      /*    sockets |= HAVE_TCP; */
      /* else tcp_sockerrno = errno; */

      /* now drop privileges (no effect if not setsuid or geteuid() == 0) */
      setuid(getuid());

      /* POSIXLY_CORRECT might break things, so unset it (the portable way) */
      environ = NULL;

      /* use the pid to mark packets as ours */
      pid = getpid();
      /* printf("pid = %u\n", pid); */

      /* get calling name the old-fashioned way for portability instead
       * of relying on the glibc-ism __progname */
      ptr = strrchr(argv[0], '/');
      if(ptr) progname = &ptr[1];
      else progname = argv[0];

      /* now set defaults. Use progname to set them initially (allows for
       * superfast check_host program when target host is up */
      cursor = list = NULL;
      table = NULL;

      mode = MODE_RTA;
      crit.rta = 500000;
      crit.pl = 80;
      warn.rta = 200000;
      warn.pl = 40;
      protocols = HAVE_ICMP | HAVE_UDP | HAVE_TCP;
      pkt_interval = 80000;  /* 80 msec packet interval by default */
      packets = 5;

      if(!strcmp(progname, "check_icmp") || !strcmp(progname, "check_ping")) {
            mode = MODE_ICMP;
            protocols = HAVE_ICMP;
      }
      else if(!strcmp(progname, "check_host")) {
            mode = MODE_HOSTCHECK;
            pkt_interval = 1000000;
            packets = 5;
            crit.rta = warn.rta = 1000000;
            crit.pl = warn.pl = 100;
      }
      else if(!strcmp(progname, "check_rta_multi")) {
            mode = MODE_ALL;
            target_interval = 0;
            pkt_interval = 50000;
            packets = 5;
      }

      /* parse the arguments */
      for(i = 1; i < argc; i++) {
            while((arg = getopt(argc, argv, "vhVw:c:n:p:t:H:i:b:I:l:")) != EOF) {
                  switch(arg) {
                  case 'v':
                        debug++;
                        break;
                  case 'b':
                        /* silently ignored for now */
                        break;
                  case 'i':
                        pkt_interval = get_timevar(optarg);
                        break;
                  case 'I':
                        target_interval = get_timevar(optarg);
                        break;
                  case 'w':
                        get_threshold(optarg, &warn);
                        break;
                  case 'c':
                        get_threshold(optarg, &crit);
                        break;
                  case 'n':
                  case 'p':
                        packets = strtoul(optarg, NULL, 0);
                        break;
                  case 't':
                        timeout = strtoul(optarg, NULL, 0);
                        if(!timeout) timeout = 10;
                        break;
                  case 'H':
                        add_target(optarg);
                        break;
                  case 'l':
                        ttl = (unsigned char)strtoul(optarg, NULL, 0);
                        break;
                  case 'd': /* implement later, for cluster checks */
                        warn_down = (unsigned char)strtoul(optarg, &ptr, 0);
                        if(ptr) {
                              crit_down = (unsigned char)strtoul(ptr + 1, NULL, 0);
                        }
                        break;
      case 'V':                 /* version */
        //print_revision (progname, revision);
        exit (STATE_OK);
      case 'h':                 /* help */
        print_help ();
        exit (STATE_OK);
                  }
            }
      }

      argv = &argv[optind];
      while(*argv) {
            add_target(*argv);
            argv++;
      }
      if(!targets) {
            errno = 0;
            crash("No hosts to check");
            exit(3);
      }

      if(!sockets) {
            if(icmp_sock == -1) {
                  errno = icmp_sockerrno;
                  crash("Failed to obtain ICMP socket");
                  return -1;
            }
            /* if(udp_sock == -1) { */
            /*    errno = icmp_sockerrno; */
            /*    crash("Failed to obtain UDP socket"); */
            /*    return -1; */
            /* } */
            /* if(tcp_sock == -1) { */
            /*    errno = icmp_sockerrno; */
            /*    crash("Failed to obtain TCP socker"); */
            /*    return -1; */
            /* } */
      }
      if(!ttl) ttl = 64;

      if(icmp_sock) {
            result = setsockopt(icmp_sock, SOL_IP, IP_TTL, &ttl, sizeof(ttl));
            if(debug) {
                  if(result == -1) printf("setsockopt failed\n");
                  else printf("ttl set to %u\n", ttl);
            }
      }

      /* stupid users should be able to give whatever thresholds they want
       * (nothing will break if they do), but some anal plugin maintainer
       * will probably add some printf() thing here later, so it might be
       * best to at least show them where to do it. ;) */
      if(warn.pl > crit.pl) warn.pl = crit.pl;
      if(warn.rta > crit.rta) warn.rta = crit.rta;
      if(warn_down > crit_down) crit_down = warn_down;

      signal(SIGINT, finish);
      signal(SIGHUP, finish);
      signal(SIGTERM, finish);
      signal(SIGALRM, finish);
      if(debug) printf("Setting alarm timeout to %u seconds\n", timeout);
      alarm(timeout);

      /* make sure we don't wait any longer than necessary */
      gettimeofday(&prog_start, &tz);
      max_completion_time =
            ((targets * packets * pkt_interval) + (targets * target_interval)) +
            (targets * packets * crit.rta) + crit.rta;

      if(debug) {
            printf("packets: %u, targets: %u\n"
                     "target_interval: %0.3f, pkt_interval %0.3f\n"
                     "crit.rta: %0.3f\n"
                     "max_completion_time: %0.3f\n",
                     packets, targets,
                     (float)target_interval / 1000, (float)pkt_interval / 1000,
                     (float)crit.rta / 1000,
                     (float)max_completion_time / 1000);
      }

      if(debug) {
            if(max_completion_time > (u_int)timeout * 1000000) {
                  printf("max_completion_time: %llu  timeout: %u\n",
                           max_completion_time, timeout);
                  printf("Timout must be at lest %llu\n",
                           max_completion_time / 1000000 + 1);
            }
      }

      icmp_pkt_size = icmp_data_size + ICMP_MINLEN;
      if(debug > 2) printf("icmp_pkt_size = %u\n", icmp_pkt_size);
      if(icmp_pkt_size < sizeof(struct icmp) + sizeof(struct icmp_ping_data)) {
            icmp_pkt_size = sizeof(struct icmp) + sizeof(struct icmp_ping_data);
      }
      if(debug > 2) printf("icmp_pkt_size = %u\n", icmp_pkt_size);

      if(debug) {
            printf("crit = {%u, %u%%}, warn = {%u, %u%%}\n",
                     crit.rta, crit.pl, warn.rta, warn.pl);
            printf("pkt_interval: %u  target_interval: %u  retry_interval: %u\n",
                     pkt_interval, target_interval, retry_interval);
            printf("icmp_pkt_size: %u  timeout: %u\n",
                     icmp_pkt_size, timeout);
      }

      if(packets > 20) {
            errno = 0;
            crash("packets is > 20 (%d)", packets);
      }

      host = list;
      table = malloc(sizeof(struct rta_host **) * (argc - 1));
      i = 0;
      while(host) {
            host->id = i;
            table[i] = host;
            host = host->next;
            i++;
      }

      run_checks();

      errno = 0;
      finish(0);

      return(0);
}

static void
run_checks()
{
      u_int i, t, result;
      u_int final_wait, time_passed;

      /* this loop might actually violate the pkt_interval or target_interval
       * settings, but only if there aren't any packets on the wire which
       * indicates that the target can handle an increased packet rate */
      for(i = 0; i < packets; i++) {
            for(t = 0; t < targets; t++) {
                  /* don't send useless packets */
                  if(!targets_alive) finish(0);
                  if(table[t]->flags & FLAG_LOST_CAUSE) {
                        if(debug) printf("%s is a lost cause. not sending any more\n",
                                                 table[t]->name);
                        continue;
                  }
                  
                  /* we're still in the game, so send next packet */
                  (void)send_icmp_ping(icmp_sock, table[t]);
                  result = wait_for_reply(icmp_sock, target_interval);
            }
            result = wait_for_reply(icmp_sock, pkt_interval * targets);
      }

      if(icmp_pkts_en_route && targets_alive) {
            time_passed = get_timevaldiff(NULL, NULL);
            final_wait = max_completion_time - time_passed;

            if(debug) {
                  printf("time_passed: %u  final_wait: %u  max_completion_time: %llu\n",
                           time_passed, final_wait, max_completion_time);
            }
            if(time_passed > max_completion_time) {
                  if(debug) printf("Time passed. Finishing up\n");
                  finish(0);
            }

            /* catch the packets that might come in within the timeframe, but
             * haven't yet */
            if(debug) printf("Waiting for %u micro-seconds (%0.3f msecs)\n",
                                     final_wait, (float)final_wait / 1000);
            result = wait_for_reply(icmp_sock, final_wait);
      }
}

/* response structure:
 * ip header   : 20 bytes
 * icmp header : 28 bytes
 * icmp echo reply : the rest
 */
static int
wait_for_reply(int sock, u_int t)
{
      int n, hlen;
      static char buf[4096];
      struct sockaddr_in resp_addr;
      struct ip *ip;
      struct icmp *icp, *sent_icmp;
      struct rta_host *host;
      struct icmp_ping_data *data;
      struct timeval wait_start, now;
      u_int tdiff, i, per_pkt_wait;

      /* if we can't listen or don't have anything to listen to, just return */
      if(!t || !icmp_pkts_en_route) return 0;

      gettimeofday(&wait_start, &tz);

      i = t;
      per_pkt_wait = t / icmp_pkts_en_route;
      while(icmp_pkts_en_route && get_timevaldiff(&wait_start, NULL) < i) {
            t = per_pkt_wait;

            /* wrap up if all targets are declared dead */
            if(!targets_alive ||
               get_timevaldiff(&prog_start, NULL) >= max_completion_time ||
               (mode == MODE_HOSTCHECK && targets_down))
            {
                  finish(0);
            }

            /* reap responses until we hit a timeout */
            n = recvfrom_wto(sock, buf, sizeof(buf),
                                     (struct sockaddr *)&resp_addr, &t);
            if(!n) {
                  if(debug > 1) {
                        printf("recvfrom_wto() timed out during a %u usecs wait\n",
                                 per_pkt_wait);
                  }
                  continue;   /* timeout for this one, so keep trying */
            }
            if(n < 0) {
                  if(debug) printf("recvfrom_wto() returned errors\n");
                  return n;
            }

            ip = (struct ip *)buf;
            if(debug > 1) printf("received %u bytes from %s\n",
                                     ntohs(ip->ip_len), inet_ntoa(resp_addr.sin_addr));

/* obsolete. alpha on tru64 provides the necessary defines, but isn't broken */
/* #if defined( __alpha__ ) && __STDC__ && !defined( __GLIBC__ ) */
            /* alpha headers are decidedly broken. Using an ansi compiler,
             * they provide ip_vhl instead of ip_hl and ip_v, so we mask
             * off the bottom 4 bits */
/*          hlen = (ip->ip_vhl & 0x0f) << 2; */
/* #else */
            hlen = ip->ip_hl << 2;
/* #endif */

            if(n < (hlen + ICMP_MINLEN)) {
                  crash("received packet too short for ICMP (%d bytes, expected %d) from %s\n",
                          n, hlen + icmp_pkt_size, inet_ntoa(resp_addr.sin_addr));
            }
            /* else if(debug) { */
            /*    printf("ip header size: %u, packet size: %u (expected %u, %u)\n", */
            /*             hlen, ntohs(ip->ip_len) - hlen, */
            /*             sizeof(struct ip), icmp_pkt_size); */
            /* } */

            /* check the response */
            icp = (struct icmp *)(buf + hlen);
            sent_icmp = (struct icmp *)(buf + hlen + ICMP_MINLEN);
            /* printf("buf: %p, icp: %p, distance: %u (expected %u)\n", */
            /*       buf, icp, */
            /*       (u_int)icp - (u_int)buf, hlen); */
            /* printf("buf: %p, sent_icmp: %p, distance: %u (expected %u)\n", */
            /*       buf, sent_icmp, */
            /*       (u_int)sent_icmp - (u_int)buf, hlen + ICMP_MINLEN); */

            if(icp->icmp_id != pid) {
                  handle_random_icmp(icp, &resp_addr);
                  continue;
            }

            if(icp->icmp_type != ICMP_ECHOREPLY || icp->icmp_seq >= targets) {
                  if(debug > 2) printf("not a proper ICMP_ECHOREPLY\n");
                  handle_random_icmp(icp, &resp_addr);
                  continue;
            }

            /* this is indeed a valid response */
            data = (struct icmp_ping_data *)(icp->icmp_data);

            host = table[icp->icmp_seq];
            gettimeofday(&now, &tz);
            tdiff = get_timevaldiff(&data->stime, &now);

            host->time_waited += tdiff;
            host->icmp_recv++;
            icmp_recv++;

            if(debug) {
                  printf("%0.3f ms rtt from %s, outgoing ttl: %u, incoming ttl: %u\n",
                           (float)tdiff / 1000, inet_ntoa(resp_addr.sin_addr),
                           ttl, ip->ip_ttl);
            }

            /* if we're in hostcheck mode, exit with limited printouts */
            if(mode == MODE_HOSTCHECK) {
                  printf("OK - %s responds to ICMP. Packet %u, rta %0.3fms|"
                           "pkt=%u;;0;%u rta=%0.3f;%0.3f;%0.3f;;\n",
                           host->name, icmp_recv, (float)tdiff / 1000,
                           icmp_recv, packets, (float)tdiff / 1000,
                           (float)warn.rta / 1000, (float)crit.rta / 1000);
                  exit(STATE_OK);
            }
      }

      return 0;
}

/* the ping functions */
static int
send_icmp_ping(int sock, struct rta_host *host)
{
      static char *buf = NULL; /* re-use so we prevent leaks */
      long int len;
      struct icmp *icp;
      struct icmp_ping_data *data;
      struct timeval tv;
      struct sockaddr *addr;

      
      if(sock == -1) {
            errno = 0;
            crash("Attempt to send on bogus socket");
            return -1;
      }
      addr = (struct sockaddr *)&host->saddr_in;

      if(!buf) {
            buf = (char *)malloc(icmp_pkt_size + sizeof(struct ip));
            if(!buf) {
                  crash("send_icmp_ping(): failed to malloc %d bytes for send buffer",
                          icmp_pkt_size);
                  return -1;  /* might be reached if we're in debug mode */
            }
      }
      memset(buf, 0, icmp_pkt_size + sizeof(struct ip));

      if((gettimeofday(&tv, &tz)) == -1) return -1;

      icp = (struct icmp *)buf;
      icp->icmp_type = ICMP_ECHO;
      icp->icmp_code = 0;
      icp->icmp_cksum = 0;
      icp->icmp_id = pid;
      icp->icmp_seq = host->id;
      data = (struct icmp_ping_data *)icp->icmp_data;
      data->ping_id = 10; /* host->icmp.icmp_sent; */
      memcpy(&data->stime, &tv, sizeof(struct timeval));
      icp->icmp_cksum = icmp_checksum((u_short *)icp, icmp_pkt_size);

      len = sendto(sock, buf, icmp_pkt_size, 0, (struct sockaddr *)addr,
                         sizeof(struct sockaddr));

      if(len < 0 || (unsigned int)len != icmp_pkt_size) {
            if(debug) printf("Failed to send ping to %s\n",
                                     inet_ntoa(host->saddr_in.sin_addr));
            return -1;
      }

      icmp_sent++;
      host->icmp_sent++;

      return 0;
}

static int
recvfrom_wto(int sock, char *buf, unsigned int len, struct sockaddr *saddr,
                   u_int *timo)
{
      u_int slen;
      int n;
      struct timeval to, then, now;
      fd_set rd, wr;

      if(!*timo) {
            if(debug) printf("*timo is not\n");
            return 0;
      }

      to.tv_sec = *timo / 1000000;
      to.tv_usec = (*timo - (to.tv_sec * 1000000));

      FD_ZERO(&rd);
      FD_ZERO(&wr);
      FD_SET(sock, &rd);
      errno = 0;
      gettimeofday(&then, &tz);
      n = select(sock + 1, &rd, &wr, NULL, &to);
      if(n < 0) crash("select() in recvfrom_wto");
      gettimeofday(&now, &tz);
      *timo = get_timevaldiff(&then, &now);

      if(!n) return 0;                    /* timeout */

      slen = sizeof(struct sockaddr);

      return recvfrom(sock, buf, len, 0, saddr, &slen);
}

static void
finish(int sig)
{
      u_int i = 0;
      unsigned char pl;
      double rta;
      struct rta_host *host;
      char *status_string[] =
      {"OK", "WARNING", "CRITICAL", "UNKNOWN", "DEPENDENT"};

      alarm(0);
      if(debug > 1) printf("finish(%d) called\n", sig);

      if(icmp_sock != -1) close(icmp_sock);
      if(udp_sock != -1) close(udp_sock);
      if(tcp_sock != -1) close(tcp_sock);

      if(debug) {
            printf("icmp_sent: %u  icmp_recv: %u  icmp_lost: %u\n",
                     icmp_sent, icmp_recv, icmp_lost);
            printf("targets: %u  targets_alive: %u\n", targets, targets_alive);
      }

      /* iterate thrice to calculate values, give output, and print perfparse */
      host = list;
      while(host) {
            if(!host->icmp_recv) {
                  /* rta 0 is ofcourse not entirely correct, but will still show up
                   * conspicuosly as missing entries in perfparse and cacti */
                  pl = 100;
                  rta = 0;
                  status = STATE_CRITICAL;
                  /* up the down counter if not already counted */
                  if(!(host->flags & FLAG_LOST_CAUSE) && targets_alive) targets_down++;
            }
            else {
                  pl = ((host->icmp_sent - host->icmp_recv) * 100) / host->icmp_sent;
                  rta = (double)host->time_waited / host->icmp_recv;
            }
            host->pl = pl;
            host->rta = rta;
            if(!status && (pl >= warn.pl || rta >= warn.rta)) status = STATE_WARNING;
            if(pl >= crit.pl || rta >= crit.rta) status = STATE_CRITICAL;

            host = host->next;
      }
      /* this is inevitable */
      if(!targets_alive) status = STATE_CRITICAL;
      printf("%s - ", status_string[status]);

      host = list;
      while(host) {
            if(debug) puts("");
            if(i) {
                  if(i < targets) printf(" :: ");
                  else printf("\n");
            }
            i++;
            if(!host->icmp_recv) {
                  status = STATE_CRITICAL;
                  if(host->flags & FLAG_LOST_CAUSE) {
                        printf("%s: %s @ %s. rta nan, lost %d%%",
                                 host->name,
                                 get_icmp_error_msg(host->icmp_type, host->icmp_code),
                                 inet_ntoa(host->error_addr),
                                 100);
                  }
                  else { /* not marked as lost cause, so we have no flags for it */
                        printf("%s: rta nan, lost 100%%", host->name);
                  }
            }
            else {      /* !icmp_recv */
                  printf("%s: rta %0.3fms, lost %u%%",
                           host->name, host->rta / 1000, host->pl);
            }

            host = host->next;
      }

      /* iterate once more for pretty perfparse output */
      printf("|");
      i = 0;
      host = list;
      while(host) {
            if(debug) puts("");
            printf("%srta=%0.3fms;%0.3f;%0.3f;0; %spl=%u%%;%u;%u;; ",
                     (targets > 1) ? host->name : "",
                     host->rta / 1000, (float)warn.rta / 1000, (float)crit.rta / 1000,
                     (targets > 1) ? host->name : "",
                     host->pl, warn.pl, crit.pl);

            host = host->next;
      }

      /* finish with an empty line */
      puts("");
      if(debug) printf("targets: %u, targets_alive: %u\n",
                               targets, targets_alive);

      exit(status);
}

static u_int
get_timevaldiff(struct timeval *early, struct timeval *later)
{
      u_int ret;
      struct timeval now;

      if(!later) {
            gettimeofday(&now, &tz);
            later = &now;
      }
      if(!early) early = &prog_start;

      /* if early > later we return 0 so as to indicate a timeout */
      if(early->tv_sec > early->tv_sec ||
         (early->tv_sec == later->tv_sec && early->tv_usec > later->tv_usec))
      {
            return 0;
      }

      ret = (later->tv_sec - early->tv_sec) * 1000000;
      ret += later->tv_usec - early->tv_usec;

      return ret;
}

static int
add_target_ip(char *arg, struct in_addr *in)
{
      struct rta_host *host;

      /* disregard obviously stupid addresses */
      if(in->s_addr == INADDR_NONE || in->s_addr == INADDR_ANY)
            return -1;

      /* no point in adding two identical IP's, so don't. ;) */
      host = list;
      while(host) {
            if(host->saddr_in.sin_addr.s_addr == in->s_addr) {
                  if(debug) printf("Identical IP already exists. Not adding %s\n", arg);
                  return -1;
            }
            host = host->next;
      }

      /* add the fresh ip */
      host = malloc(sizeof(struct rta_host));
      if(!host) {
            crash("add_target_ip(%s, %s): malloc(%d) failed",
                    arg, inet_ntoa(*in), sizeof(struct rta_host));
      }
      memset(host, 0, sizeof(struct rta_host));

      /* set the values. use calling name for output */
      host->name = strdup(arg);

      /* fill out the sockaddr_in struct */
      host->saddr_in.sin_family = AF_INET;
      host->saddr_in.sin_addr.s_addr = in->s_addr;

      if(!list) list = cursor = host;
      else cursor->next = host;

      cursor = host;
      targets++;

      return 0;
}

/* wrapper for add_target_ip */
static int
add_target(char *arg)
{
      int i;
      struct hostent *he;
      struct in_addr *in, ip;

      /* don't resolve if we don't have to */
      if((ip.s_addr = inet_addr(arg)) != INADDR_NONE) {
            /* don't add all ip's if we were given a specific one */
            return add_target_ip(arg, &ip);
            /* he = gethostbyaddr((char *)in, sizeof(struct in_addr), AF_INET); */
            /* if(!he) return add_target_ip(arg, in); */
      }
      else {
            errno = 0;
            he = gethostbyname(arg);
            if(!he) {
                  errno = 0;
                  crash("Failed to resolve %s", arg);
                  return -1;
            }
      }

      /* possibly add all the IP's as targets */
      for(i = 0; he->h_addr_list[i]; i++) {
            in = (struct in_addr *)he->h_addr_list[i];
            add_target_ip(arg, in);

            /* this is silly, but it works */
            if(mode == MODE_HOSTCHECK || mode == MODE_ALL) {
                  printf("mode: %d\n", mode);
                  continue;
            }
            break;
      }

      return 0;
}
/*
 * u = micro
 * m = milli
 * s = seconds
 * return value is in microseconds
 */
static u_int
get_timevar(const char *str)
{
      char p, u, *ptr;
      unsigned int len;
      u_int i, d;             /* integer and decimal, respectively */
      u_int factor = 1000;    /* default to milliseconds */

      if(!str) return 0;
      len = strlen(str);
      if(!len) return 0;

      /* unit might be given as ms|m (millisec),
       * us|u (microsec) or just plain s, for seconds */
      u = p = '\0';
      u = str[len - 1];
      if(len >= 2 && !isdigit((int)str[len - 2])) p = str[len - 2];
      if(p && u == 's') u = p;
      else if(!p) p = u;
      if(debug > 2) printf("evaluating %s, u: %c, p: %c\n", str, u, p);

      if(u == 'u') factor = 1;            /* microseconds */
      else if(u == 'm') factor = 1000;    /* milliseconds */
      else if(u == 's') factor = 1000000; /* seconds */
      if(debug > 2) printf("factor is %u\n", factor);

      i = strtoul(str, &ptr, 0);
      if(!ptr || *ptr != '.' || strlen(ptr) < 2 || factor == 1)
            return i * factor;

      /* time specified in usecs can't have decimal points, so ignore them */
      if(factor == 1) return i;

      d = strtoul(ptr + 1, NULL, 0);

      /* d is decimal, so get rid of excess digits */
      while(d >= factor) d /= 10;

      /* the last parenthesis avoids floating point exceptions. */
      return ((i * factor) + (d * (factor / 10)));
}

/* not too good at checking errors, but it'll do (main() should barfe on -1) */
static int
get_threshold(char *str, threshold *th)
{
      char *p = NULL, i = 0;

      if(!str || !strlen(str) || !th) return -1;

      /* pointer magic slims code by 10 lines. i is bof-stop on stupid libc's */
      p = &str[strlen(str) - 1];
      while(p != &str[1]) {
            if(*p == '%') *p = '\0';
            else if(*p == ',' && i) {
                  *p = '\0';  /* reset it so get_timevar(str) works nicely later */
                  th->pl = (unsigned char)strtoul(p+1, NULL, 0);
                  break;
            }
            i = 1;
            p--;
      }
      th->rta = get_timevar(str);

      if(!th->rta) return -1;

      if(th->rta > MAXTTL * 1000000) th->rta = MAXTTL * 1000000;
      if(th->pl > 100) th->pl = 100;

      return 0;
}

unsigned short
icmp_checksum(unsigned short *p, int n)
{
      register unsigned short cksum;
      register long sum = 0;

      while(n > 1) {
            sum += *p++;
            n -= 2;
      }

      /* mop up the occasional odd byte */
      if(n == 1) sum += (unsigned char)*p;

      sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */
      sum += (sum >> 16);                 /* add carry */
      cksum = ~sum;                       /* ones-complement, trunc to 16 bits */

      return cksum;
}

void
print_help(void)
{

  //print_revision (progname, revision);
  
  printf ("Copyright (c) 2005 Andreas Ericsson <ae@op5.se>\n");
  printf (COPYRIGHT, copyright, email);
  
  printf ("\n\n");
  
  print_usage ();
  
  printf (_(UT_HELP_VRSN));
  
  printf (" %s\n", "-H");
  printf ("    %s\n", _("specify a target"));
  printf (" %s\n", "-w");
  printf ("    %s", _("warning threshold (currently "));
  printf ("%0.3fms,%u%%)\n", (float)warn.rta / 1000 , warn.pl / 1000);
  printf (" %s\n", "-c");
  printf ("    %s", _("critical threshold (currently "));
  printf ("%0.3fms,%u%%)\n", (float)crit.rta), crit.pl;
  printf (" %s\n", "-n");
  printf ("    %s", _("number of packets to send (currently "));
  printf ("%u)\n",packets);
  printf (" %s\n", "-i");
  printf ("    %s", _("max packet interval (currently "));
  printf ("%0.3fms)\n",(float)pkt_interval / 1000);
  printf (" %s\n", "-I");
  printf ("    %s", _("max target interval (currently "));
  printf ("%0.3fms)\n", (float)target_interval / 1000);
  printf (" %s\n", "-l");
  printf ("    %s", _("TTL on outgoing packets (currently "));
  printf ("%u)", ttl);
  printf (" %s\n", "-t");
  printf ("    %s",_("timeout value (seconds, currently  "));
  printf ("%u)\n", timeout);
  printf (" %s\n", "-b");
  printf ("    %s\n", _("icmp packet size (currenly ignored)"));
  printf (" %s\n", "-v");
  printf ("    %s\n", _("verbose"));

  printf ("\n");
      printf ("%s\n\n", _("The -H switch is optional. Naming a host (or several) to check is not."));
  printf ("%s\n", _("Threshold format for -w and -c is 200.25,60% for 200.25 msec RTA and 60%"));
  printf ("%s\n", _("packet loss.  The default values should work well for most users."));
  printf ("%s\n", _("You can specify different RTA factors using the standardized abbreviations"));
  printf ("%s\n\n", _("us (microseconds), ms (milliseconds, default) or just plain s for seconds."));
  printf ("%s\n", _("Threshold format for -d is warn,crit.  12,14 means WARNING if >= 12 hops"));
  printf ("%s\n", _("are spent and CRITICAL if >= 14 hops are spent."));
  printf ("%s\n\n", _("NOTE: Some systems decrease TTL when forming ICMP_ECHOREPLY, others do not."));
  printf ("%s\n\n", _("The -v switch can be specified several times for increased verbosity."));
/*  printf ("%s\n", _("Long options are currently unsupported."));
  printf ("%s\n", _("Options marked with * require an argument"));
*/
  printf (_(UT_SUPPORT));
  
  printf (_(UT_NOWARRANTY));
}



void
print_usage (void)
{
  printf (_("Usage:"));
  printf(" %s [options] [-H] host1 host2 hostn\n", progname);
}

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