check_icmp: Support "--help" and "--version"

[monitoring-plugins.git] / plugins-root / check_icmp.c

/*****************************************************************************
* 
* Nagios check_icmp plugin
* 
* License: GPL
* Copyright (c) 2005-2008 Nagios Plugins Development Team
* Original Author : Andreas Ericsson <ae@op5.se>
* 
* 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.
* 
* 
* 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 3 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, see <http://www.gnu.org/licenses/>.
* 
* 
*****************************************************************************/

/* progname may change */
/* char *progname = "check_icmp"; */
char *progname;
const char *copyright = "2005-2008";
const char *email = "nagiosplug-devel@lists.sourceforge.net";

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

#if HAVE_SYS_SOCKIO_H
#include <sys/sockio.h>
#endif
#include <sys/ioctl.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 <net/if.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>
#include <float.h>


/** sometimes undefined system macros (quite a few, actually) **/
#ifndef MAXTTL
# define MAXTTL 255
#endif
#ifndef INADDR_NONE
# define INADDR_NONE (in_addr_t)(-1)
#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

#ifndef DBL_MAX
# define DBL_MAX 9.9999999999e999
#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 */
        double rtmax;                /* max rtt */
        double rtmin;                /* min rtt */
        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 in_addr_t get_ip_address(const char *);
static int wait_for_reply(int, u_int);
static int recvfrom_wto(int, void *, 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 void set_source_ip(char *);
static int add_target(char *);
static int add_target_ip(char *, struct in_addr *);
static int handle_random_icmp(unsigned char *, 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_data_size = DEFAULT_PING_DATA_SIZE;
static unsigned short icmp_pkt_size = DEFAULT_PING_DATA_SIZE + ICMP_MINLEN;

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 */
static int min_hosts_alive = -1;
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 const char *
get_icmp_error_msg(unsigned char icmp_type, unsigned char icmp_code)
{
        const 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(unsigned char *packet, struct sockaddr_in *addr)
{
        struct icmp p, sent_icmp;
        struct rta_host *host = NULL;

        memcpy(&p, packet, sizeof(p));
        if(p.icmp_type == ICMP_ECHO && ntohs(p.icmp_id) == pid) {
                /* echo request from us to us (pinging localhost) */
                return 0;
        }

        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 */
        memcpy(&sent_icmp, packet + 28, sizeof(sent_icmp));
        if(sent_icmp.icmp_type != ICMP_ECHO || ntohs(sent_icmp.icmp_id) != pid ||
           ntohs(sent_icmp.icmp_seq) >= targets*packets)
        {
                if(debug) printf("Packet is no response to a packet we sent\n");
                return 0;
        }

        /* it is indeed a response for us */
        host = table[ntohs(sent_icmp.icmp_seq)/packets];
        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;

        setlocale (LC_ALL, "");
        bindtextdomain (PACKAGE, LOCALEDIR);
        textdomain (PACKAGE);

        /* print a helpful error message if geteuid != 0 */
        np_warn_if_not_root();

        /* 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 */
        /* Some systems have 32-bit pid_t so mask off only 16 bits */
        pid = getpid() & 0xffff;
        /* 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 extra opts if any */
        argv=np_extra_opts(&argc, argv, progname);

        /* support "--help" and "--version" */
        if(argc == 2) {
                if(!strcmp(argv[1], "--help"))
                        strcpy(argv[1], "-h");
                if(!strcmp(argv[1], "--version"))
                        strcpy(argv[1], "-V");
        }

        /* parse the arguments */
        for(i = 1; i < argc; i++) {
                while((arg = getopt(argc, argv, "vhVw:c:n:p:t:H:s:i:b:I:l:m:")) != EOF) {
                        long size;
                        switch(arg) {
                        case 'v':
                                debug++;
                                break;
                        case 'b':
                                size = strtol(optarg,NULL,0);
                                if (size >= (sizeof(struct icmp) + sizeof(struct icmp_ping_data)) &&
                                    size < MAX_PING_DATA) {
                                        icmp_data_size = size;
                                        icmp_pkt_size = size + ICMP_MINLEN;
                                } else
                                        usage_va("ICMP data length must be between: %d and %d",
                                                 sizeof(struct icmp) + sizeof(struct icmp_ping_data),
                                                 MAX_PING_DATA - 1);

                                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 'm':
                                min_hosts_alive = (int)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 's': /* specify source IP address */
                                set_source_ip(optarg);
                                break;
      case 'V':                 /* version */
        print_revision (progname, NP_VERSION);
        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);
                }
        }

        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);
        }

        if(min_hosts_alive < -1) {
                errno = 0;
                crash("minimum alive hosts is negative (%i)", min_hosts_alive);
        }

        host = list;
        table = malloc(sizeof(struct rta_host **) * targets);
        i = 0;
        while(host) {
                host->id = i*packets;
                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 unsigned char buf[4096];
        struct sockaddr_in resp_addr;
        struct ip *ip;
        struct icmp icp;
        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 */
                memcpy(&icp, buf + hlen, sizeof(icp));

                if(ntohs(icp.icmp_id) != pid || icp.icmp_type != ICMP_ECHOREPLY ||
                   ntohs(icp.icmp_seq) >= targets*packets) {
                        if(debug > 2) printf("not a proper ICMP_ECHOREPLY\n");
                        handle_random_icmp(buf + hlen, &resp_addr);
                        continue;
                }

                /* this is indeed a valid response */
                memcpy(&data, icp.icmp_data, sizeof(data));
                if (debug > 2)
                        printf("ICMP echo-reply of len %u, id %u, seq %u, cksum 0x%X\n",
                               sizeof(data), ntohs(icp.icmp_id), ntohs(icp.icmp_seq), icp.icmp_cksum);

                host = table[ntohs(icp.icmp_seq)/packets];
                gettimeofday(&now, &tz);
                tdiff = get_timevaldiff(&data.stime, &now);

                host->time_waited += tdiff;
                host->icmp_recv++;
                icmp_recv++;
                if (tdiff > host->rtmax)
                        host->rtmax = tdiff;
                if (tdiff < host->rtmin)
                        host->rtmin = tdiff;

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

                /* 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 union {
                void *buf; /* re-use so we prevent leaks */
                struct icmp *icp;
                u_short *cksum_in;
        } packet = { NULL };
        long int len;
        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(!packet.buf) {
                if (!(packet.buf = malloc(icmp_pkt_size))) {
                        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(packet.buf, 0, icmp_pkt_size);

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

        data.ping_id = 10; /* host->icmp.icmp_sent; */
        memcpy(&data.stime, &tv, sizeof(tv));
        memcpy(&packet.icp->icmp_data, &data, sizeof(data));
        packet.icp->icmp_type = ICMP_ECHO;
        packet.icp->icmp_code = 0;
        packet.icp->icmp_cksum = 0;
        packet.icp->icmp_id = htons(pid);
        packet.icp->icmp_seq = htons(host->id++);
        packet.icp->icmp_cksum = icmp_checksum(packet.cksum_in, icmp_pkt_size);

        if (debug > 2)
                printf("Sending ICMP echo-request of len %u, id %u, seq %u, cksum 0x%X to host %s\n",
                       sizeof(data), ntohs(packet.icp->icmp_id), ntohs(packet.icp->icmp_seq), packet.icp->icmp_cksum, host->name);

        len = sendto(sock, packet.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, void *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;
        const char *status_string[] =
        {"OK", "WARNING", "CRITICAL", "UNKNOWN", "DEPENDENT"};
        int hosts_ok = 0;
        int hosts_warn = 0;

        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(pl >= crit.pl || rta >= crit.rta) {
                        status = STATE_CRITICAL;
                }
                else if(!status && (pl >= warn.pl || rta >= warn.rta)) {
                        status = STATE_WARNING;
                        hosts_warn++;
                }
                else {
                        hosts_ok++;
                }

                host = host->next;
        }
        /* this is inevitable */
        if(!targets_alive) status = STATE_CRITICAL;
        if(min_hosts_alive > -1) {
                if(hosts_ok >= min_hosts_alive) status = STATE_OK;
                else if((hosts_ok + hosts_warn) >= min_hosts_alive) status = STATE_WARNING;
        }
        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;; %srtmax=%0.3fms;;;; %srtmin=%0.3fms;;;; ",
                           (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,
                           (targets > 1) ? host->name : "", (float)host->rtmax / 1000,
                           (targets > 1) ? host->name : "", (host->rtmin < DBL_MAX) ? (float)host->rtmin / 1000 : (float)0);

                host = host->next;
        }

        if(min_hosts_alive > -1) {
                if(hosts_ok >= min_hosts_alive) status = STATE_OK;
                else if((hosts_ok + hosts_warn) >= min_hosts_alive) status = STATE_WARNING;
        }

        /* finish with an empty line */
        puts("");
        if(debug) printf("targets: %u, targets_alive: %u, hosts_ok: %u, hosts_warn: %u, min_hosts_alive: %i\n",
                                         targets, targets_alive, hosts_ok, hosts_warn, min_hosts_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 > later->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;

        host->rtmin = DBL_MAX;

        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) {
                        if(debug > 2) printf("mode: %d\n", mode);
                        continue;
                }
                break;
        }

        return 0;
}

static void
set_source_ip(char *arg)
{
        struct sockaddr_in src;

        memset(&src, 0, sizeof(src));
        src.sin_family = AF_INET;
        if((src.sin_addr.s_addr = inet_addr(arg)) == INADDR_NONE)
                src.sin_addr.s_addr = get_ip_address(arg);
        if(bind(icmp_sock, (struct sockaddr *)&src, sizeof(src)) == -1)
                crash("Cannot bind to IP address %s", arg);
}

/* TODO: Move this to netutils.c and also change check_dhcp to use that. */
static in_addr_t
get_ip_address(const char *ifname)
{
#if defined(SIOCGIFADDR)
        struct ifreq ifr;
        struct sockaddr_in ip;

        strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name) - 1);
        ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = '\0';
        if(ioctl(icmp_sock, SIOCGIFADDR, &ifr) == -1)
                crash("Cannot determine IP address of interface %s", ifname);
        memcpy(&ip, &ifr.ifr_addr, sizeof(ip));
        return ip.sin_addr.s_addr;
#else
        errno = 0;
        crash("Cannot get interface IP address on this platform.");
#endif
}

/*
 * 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);*/ /* FIXME: Why? */

  printf ("Copyright (c) 2005 Andreas Ericsson <ae@op5.se>\n");
  printf (COPYRIGHT, copyright, email);

  printf ("\n\n");

  print_usage ();

  printf (UT_HELP_VRSN);
  printf (UT_EXTRA_OPTS);

  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);
  printf (" %s\n", "-c");
  printf ("    %s", _("critical threshold (currently "));
  printf ("%0.3fms,%u%%)\n", (float)crit.rta / 1000, crit.pl);
  printf (" %s\n", "-s");
  printf ("    %s\n", _("specify a source IP address or device name"));
  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", "-m");
  printf ("    %s",_("number of alive hosts required for success"));
  printf ("\n");
  printf (" %s\n", "-l");
  printf ("    %s", _("TTL on outgoing packets (currently "));
  printf ("%u)\n", ttl);
  printf (" %s\n", "-t");
  printf ("    %s",_("timeout value (seconds, currently  "));
  printf ("%u)\n", timeout);
  printf (" %s\n", "-b");
  printf ("    %s\n", _("Number of icmp data bytes to send"));
  printf ("    %s %u + %d)\n", _("Packet size will be data bytes + icmp header (currently"),icmp_data_size, ICMP_MINLEN);
  printf (" %s\n", "-v");
  printf ("    %s\n", _("verbose"));

  printf ("\n");
  printf ("%s\n", _("Notes:"));
  printf (" %s\n", _("The -H switch is optional. Naming a host (or several) to check is not."));
  printf ("\n");
  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", _("us (microseconds), ms (milliseconds, default) or just plain s for seconds."));
/* -d not yet implemented */
/*  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 ("\n");
  printf (" %s\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);
}



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