Addition to help to state that -f will always return OK if ssh command

[monitoring-plugins.git] / plugins / check_ntp_time.c

/*****************************************************************************
* 
* Nagios check_ntp_time plugin
* 
* License: GPL
* Copyright (c) 2006 Sean Finney <seanius@seanius.net>
* Copyright (c) 2006-2008 Nagios Plugins Development Team
* 
* Last Modified: $Date$
* 
* Description:
* 
* This file contains the check_ntp_time plugin
* 
* This plugin checks the clock offset between the local host and a
* remote NTP server. It is independent of any commandline programs or
* external libraries.
* 
* If you'd rather want to monitor an NTP server, please use
* check_ntp_peer.
* 
* 
* 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/>.
* 
* $Id$
* 
*****************************************************************************/

const char *progname = "check_ntp_time";
const char *revision = "$Revision$";
const char *copyright = "2006-2008";
const char *email = "nagiosplug-devel@lists.sourceforge.net";

#include "common.h"
#include "netutils.h"
#include "utils.h"

static char *server_address=NULL;
static int verbose=0;
static int quiet=0;
static char *owarn="60";
static char *ocrit="120";

int process_arguments (int, char **);
thresholds *offset_thresholds = NULL;
void print_help (void);
void print_usage (void);

/* number of times to perform each request to get a good average. */
#define AVG_NUM 4

/* max size of control message data */
#define MAX_CM_SIZE 468

/* this structure holds everything in an ntp request/response as per rfc1305 */
typedef struct {
        uint8_t flags;       /* byte with leapindicator,vers,mode. see macros */
        uint8_t stratum;     /* clock stratum */
        int8_t poll;         /* polling interval */
        int8_t precision;    /* precision of the local clock */
        int32_t rtdelay;     /* total rt delay, as a fixed point num. see macros */
        uint32_t rtdisp;     /* like above, but for max err to primary src */
        uint32_t refid;      /* ref clock identifier */
        uint64_t refts;      /* reference timestamp.  local time local clock */
        uint64_t origts;     /* time at which request departed client */
        uint64_t rxts;       /* time at which request arrived at server */
        uint64_t txts;       /* time at which request departed server */
} ntp_message;

/* this structure holds data about results from querying offset from a peer */
typedef struct {
        time_t waiting;         /* ts set when we started waiting for a response */ 
        int num_responses;      /* number of successfully recieved responses */
        uint8_t stratum;        /* copied verbatim from the ntp_message */
        double rtdelay;         /* converted from the ntp_message */
        double rtdisp;          /* converted from the ntp_message */
        double offset[AVG_NUM]; /* offsets from each response */
        uint8_t flags;       /* byte with leapindicator,vers,mode. see macros */
} ntp_server_results;

/* bits 1,2 are the leap indicator */
#define LI_MASK 0xc0
#define LI(x) ((x&LI_MASK)>>6)
#define LI_SET(x,y) do{ x |= ((y<<6)&LI_MASK); }while(0)
/* and these are the values of the leap indicator */
#define LI_NOWARNING 0x00
#define LI_EXTRASEC 0x01
#define LI_MISSINGSEC 0x02
#define LI_ALARM 0x03
/* bits 3,4,5 are the ntp version */
#define VN_MASK 0x38
#define VN(x)   ((x&VN_MASK)>>3)
#define VN_SET(x,y)     do{ x |= ((y<<3)&VN_MASK); }while(0)
#define VN_RESERVED 0x02
/* bits 6,7,8 are the ntp mode */
#define MODE_MASK 0x07
#define MODE(x) (x&MODE_MASK)
#define MODE_SET(x,y)   do{ x |= (y&MODE_MASK); }while(0)
/* here are some values */
#define MODE_CLIENT 0x03
#define MODE_CONTROLMSG 0x06
/* In control message, bits 8-10 are R,E,M bits */
#define REM_MASK 0xe0
#define REM_RESP 0x80
#define REM_ERROR 0x40
#define REM_MORE 0x20
/* In control message, bits 11 - 15 are opcode */
#define OP_MASK 0x1f
#define OP_SET(x,y)   do{ x |= (y&OP_MASK); }while(0)
#define OP_READSTAT 0x01
#define OP_READVAR  0x02
/* In peer status bytes, bits 6,7,8 determine clock selection status */
#define PEER_SEL(x) ((ntohs(x)>>8)&0x07)
#define PEER_INCLUDED 0x04
#define PEER_SYNCSOURCE 0x06

/**
 ** a note about the 32-bit "fixed point" numbers:
 **
 they are divided into halves, each being a 16-bit int in network byte order:
 - the first 16 bits are an int on the left side of a decimal point.
 - the second 16 bits represent a fraction n/(2^16)
 likewise for the 64-bit "fixed point" numbers with everything doubled :) 
 **/

/* macros to access the left/right 16 bits of a 32-bit ntp "fixed point"
   number.  note that these can be used as lvalues too */
#define L16(x) (((uint16_t*)&x)[0])
#define R16(x) (((uint16_t*)&x)[1])
/* macros to access the left/right 32 bits of a 64-bit ntp "fixed point"
   number.  these too can be used as lvalues */
#define L32(x) (((uint32_t*)&x)[0])
#define R32(x) (((uint32_t*)&x)[1])

/* ntp wants seconds since 1/1/00, epoch is 1/1/70.  this is the difference */
#define EPOCHDIFF 0x83aa7e80UL

/* extract a 32-bit ntp fixed point number into a double */
#define NTP32asDOUBLE(x) (ntohs(L16(x)) + (double)ntohs(R16(x))/65536.0)

/* likewise for a 64-bit ntp fp number */
#define NTP64asDOUBLE(n) (double)(((uint64_t)n)?\
                         (ntohl(L32(n))-EPOCHDIFF) + \
                         (.00000001*(0.5+(double)(ntohl(R32(n))/42.94967296))):\
                         0)

/* convert a struct timeval to a double */
#define TVasDOUBLE(x) (double)(x.tv_sec+(0.000001*x.tv_usec))

/* convert an ntp 64-bit fp number to a struct timeval */
#define NTP64toTV(n,t) \
        do{ if(!n) t.tv_sec = t.tv_usec = 0; \
            else { \
                        t.tv_sec=ntohl(L32(n))-EPOCHDIFF; \
                        t.tv_usec=(int)(0.5+(double)(ntohl(R32(n))/4294.967296)); \
                } \
        }while(0)

/* convert a struct timeval to an ntp 64-bit fp number */
#define TVtoNTP64(t,n) \
        do{ if(!t.tv_usec && !t.tv_sec) n=0x0UL; \
                else { \
                        L32(n)=htonl(t.tv_sec + EPOCHDIFF); \
                        R32(n)=htonl((uint64_t)((4294.967296*t.tv_usec)+.5)); \
                } \
        } while(0)

/* NTP control message header is 12 bytes, plus any data in the data
 * field, plus null padding to the nearest 32-bit boundary per rfc.
 */
#define SIZEOF_NTPCM(m) (12+ntohs(m.count)+((m.count)?4-(ntohs(m.count)%4):0))

/* finally, a little helper or two for debugging: */
#define DBG(x) do{if(verbose>1){ x; }}while(0);
#define PRINTSOCKADDR(x) \
        do{ \
                printf("%u.%u.%u.%u", (x>>24)&0xff, (x>>16)&0xff, (x>>8)&0xff, x&0xff);\
        }while(0);

/* calculate the offset of the local clock */
static inline double calc_offset(const ntp_message *m, const struct timeval *t){
        double client_tx, peer_rx, peer_tx, client_rx;
        client_tx = NTP64asDOUBLE(m->origts);
        peer_rx = NTP64asDOUBLE(m->rxts);
        peer_tx = NTP64asDOUBLE(m->txts);
        client_rx=TVasDOUBLE((*t));
        return (.5*((peer_tx-client_rx)+(peer_rx-client_tx)));
}

/* print out a ntp packet in human readable/debuggable format */
void print_ntp_message(const ntp_message *p){
        struct timeval ref, orig, rx, tx;

        NTP64toTV(p->refts,ref);
        NTP64toTV(p->origts,orig);
        NTP64toTV(p->rxts,rx);
        NTP64toTV(p->txts,tx);

        printf("packet contents:\n");
        printf("\tflags: 0x%.2x\n", p->flags);
        printf("\t  li=%d (0x%.2x)\n", LI(p->flags), p->flags&LI_MASK);
        printf("\t  vn=%d (0x%.2x)\n", VN(p->flags), p->flags&VN_MASK);
        printf("\t  mode=%d (0x%.2x)\n", MODE(p->flags), p->flags&MODE_MASK);
        printf("\tstratum = %d\n", p->stratum);
        printf("\tpoll = %g\n", pow(2, p->poll));
        printf("\tprecision = %g\n", pow(2, p->precision));
        printf("\trtdelay = %-.16g\n", NTP32asDOUBLE(p->rtdelay));
        printf("\trtdisp = %-.16g\n", NTP32asDOUBLE(p->rtdisp));
        printf("\trefid = %x\n", p->refid);
        printf("\trefts = %-.16g\n", NTP64asDOUBLE(p->refts));
        printf("\torigts = %-.16g\n", NTP64asDOUBLE(p->origts));
        printf("\trxts = %-.16g\n", NTP64asDOUBLE(p->rxts));
        printf("\ttxts = %-.16g\n", NTP64asDOUBLE(p->txts));
}

void setup_request(ntp_message *p){
        struct timeval t;

        memset(p, 0, sizeof(ntp_message));
        LI_SET(p->flags, LI_ALARM);
        VN_SET(p->flags, 4);
        MODE_SET(p->flags, MODE_CLIENT);
        p->poll=4;
        p->precision=(int8_t)0xfa;
        L16(p->rtdelay)=htons(1);
        L16(p->rtdisp)=htons(1);

        gettimeofday(&t, NULL);
        TVtoNTP64(t,p->txts);
}

/* select the "best" server from a list of servers, and return its index.
 * this is done by filtering servers based on stratum, dispersion, and
 * finally round-trip delay. */
int best_offset_server(const ntp_server_results *slist, int nservers){
        int i=0, cserver=0, best_server=-1;

        /* for each server */
        for(cserver=0; cserver<nservers; cserver++){
                /* We don't want any servers that fails these tests */
                /* Sort out servers that didn't respond or responede with a 0 stratum;
                 * stratum 0 is for reference clocks so no NTP server should ever report
                 * a stratum 0 */
                if ( slist[cserver].stratum == 0){
                        if (verbose) printf("discarding peer %d: stratum=%d\n", cserver, slist[cserver].stratum);
                        continue;
                }
                /* Sort out servers with error flags */
                if ( LI(slist[cserver].flags) == LI_ALARM ){
                        if (verbose) printf("discarding peer %d: flags=%d\n", cserver, LI(slist[cserver].flags));
                        continue;
                }

                /* If we don't have a server yet, use the first one */
                if (best_server == -1) {
                        best_server = cserver;
                        DBG(printf("using peer %d as our first candidate\n", best_server));
                        continue;
                }

                /* compare the server to the best one we've seen so far */
                /* does it have an equal or better stratum? */
                DBG(printf("comparing peer %d with peer %d\n", cserver, best_server));
                if(slist[cserver].stratum <= slist[best_server].stratum){
                        DBG(printf("stratum for peer %d <= peer %d\n", cserver, best_server));
                        /* does it have an equal or better dispersion? */
                        if(slist[cserver].rtdisp <= slist[best_server].rtdisp){
                                DBG(printf("dispersion for peer %d <= peer %d\n", cserver, best_server));
                                /* does it have a better rtdelay? */
                                if(slist[cserver].rtdelay < slist[best_server].rtdelay){
                                        DBG(printf("rtdelay for peer %d < peer %d\n", cserver, best_server));
                                        best_server = cserver;
                                        DBG(printf("peer %d is now our best candidate\n", best_server));
                                }
                        }
                }
        }

        if(best_server >= 0) {
                DBG(printf("best server selected: peer %d\n", best_server));
                return best_server;
        } else {
                DBG(printf("no peers meeting synchronization criteria :(\n"));
                return -1;
        }
}

/* do everything we need to get the total average offset
 * - we use a certain amount of parallelization with poll() to ensure
 *   we don't waste time sitting around waiting for single packets. 
 * - we also "manually" handle resolving host names and connecting, because
 *   we have to do it in a way that our lazy macros don't handle currently :( */
double offset_request(const char *host, int *status){
        int i=0, j=0, ga_result=0, num_hosts=0, *socklist=NULL, respnum=0;
        int servers_completed=0, one_written=0, one_read=0, servers_readable=0, best_index=-1;
        time_t now_time=0, start_ts=0;
        ntp_message *req=NULL;
        double avg_offset=0.;
        struct timeval recv_time;
        struct addrinfo *ai=NULL, *ai_tmp=NULL, hints;
        struct pollfd *ufds=NULL;
        ntp_server_results *servers=NULL;

        /* setup hints to only return results from getaddrinfo that we'd like */
        memset(&hints, 0, sizeof(struct addrinfo));
        hints.ai_family = address_family;
        hints.ai_protocol = IPPROTO_UDP;
        hints.ai_socktype = SOCK_DGRAM;

        /* fill in ai with the list of hosts resolved by the host name */
        ga_result = getaddrinfo(host, "123", &hints, &ai);
        if(ga_result!=0){
                die(STATE_UNKNOWN, "error getting address for %s: %s\n",
                    host, gai_strerror(ga_result));
        }

        /* count the number of returned hosts, and allocate stuff accordingly */
        for(ai_tmp=ai; ai_tmp!=NULL; ai_tmp=ai_tmp->ai_next){ num_hosts++; }
        req=(ntp_message*)malloc(sizeof(ntp_message)*num_hosts);
        if(req==NULL) die(STATE_UNKNOWN, "can not allocate ntp message array");
        socklist=(int*)malloc(sizeof(int)*num_hosts);
        if(socklist==NULL) die(STATE_UNKNOWN, "can not allocate socket array");
        ufds=(struct pollfd*)malloc(sizeof(struct pollfd)*num_hosts);
        if(ufds==NULL) die(STATE_UNKNOWN, "can not allocate socket array");
        servers=(ntp_server_results*)malloc(sizeof(ntp_server_results)*num_hosts);
        if(servers==NULL) die(STATE_UNKNOWN, "can not allocate server array");
        memset(servers, 0, sizeof(ntp_server_results)*num_hosts);
        DBG(printf("Found %d peers to check\n", num_hosts));

        /* setup each socket for writing, and the corresponding struct pollfd */
        ai_tmp=ai;
        for(i=0;ai_tmp;i++){
                socklist[i]=socket(ai_tmp->ai_family, SOCK_DGRAM, IPPROTO_UDP);
                if(socklist[i] == -1) {
                        perror(NULL);
                        die(STATE_UNKNOWN, "can not create new socket");
                }
                if(connect(socklist[i], ai_tmp->ai_addr, ai_tmp->ai_addrlen)){
                        die(STATE_UNKNOWN, "can't create socket connection");
                } else {
                        ufds[i].fd=socklist[i];
                        ufds[i].events=POLLIN;
                        ufds[i].revents=0;
                }
                ai_tmp = ai_tmp->ai_next;
        }

        /* now do AVG_NUM checks to each host. We stop before timeout/2 seconds
         * have passed in order to ensure post-processing and jitter time. */
        now_time=start_ts=time(NULL);
        while(servers_completed<num_hosts && now_time-start_ts <= socket_timeout/2){
                /* loop through each server and find each one which hasn't
                 * been touched in the past second or so and is still lacking
                 * some responses. For each of these servers, send a new request,
                 * and update the "waiting" timestamp with the current time. */
                one_written=0;
                now_time=time(NULL);

                for(i=0; i<num_hosts; i++){
                        if(servers[i].waiting<now_time && servers[i].num_responses<AVG_NUM){
                                if(verbose && servers[i].waiting != 0) printf("re-");
                                if(verbose) printf("sending request to peer %d\n", i);
                                setup_request(&req[i]);
                                write(socklist[i], &req[i], sizeof(ntp_message));
                                servers[i].waiting=now_time;
                                one_written=1;
                                break;
                        }
                }

                /* quickly poll for any sockets with pending data */
                servers_readable=poll(ufds, num_hosts, 100);
                if(servers_readable==-1){
                        perror("polling ntp sockets");
                        die(STATE_UNKNOWN, "communication errors");
                }

                /* read from any sockets with pending data */
                for(i=0; servers_readable && i<num_hosts; i++){
                        if(ufds[i].revents&POLLIN && servers[i].num_responses < AVG_NUM){
                                if(verbose) {
                                        printf("response from peer %d: ", i);
                                }

                                read(ufds[i].fd, &req[i], sizeof(ntp_message));
                                gettimeofday(&recv_time, NULL);
                                DBG(print_ntp_message(&req[i]));
                                respnum=servers[i].num_responses++;
                                servers[i].offset[respnum]=calc_offset(&req[i], &recv_time);
                                if(verbose) {
                                        printf("offset %.10g\n", servers[i].offset[respnum]);
                                }
                                servers[i].stratum=req[i].stratum;
                                servers[i].rtdisp=NTP32asDOUBLE(req[i].rtdisp);
                                servers[i].rtdelay=NTP32asDOUBLE(req[i].rtdelay);
                                servers[i].waiting=0;
                                servers[i].flags=req[i].flags;
                                servers_readable--;
                                one_read = 1;
                                if(servers[i].num_responses==AVG_NUM) servers_completed++;
                        }
                }
                /* lather, rinse, repeat. */
        }

        if (one_read == 0) {
                die(STATE_CRITICAL, "NTP CRITICAL: No response from NTP server\n");
        }

        /* now, pick the best server from the list */
        best_index=best_offset_server(servers, num_hosts);
        if(best_index < 0){
                *status=STATE_UNKNOWN;
        } else {
                /* finally, calculate the average offset */
                for(i=0; i<servers[best_index].num_responses;i++){
                        avg_offset+=servers[best_index].offset[j];
                }
                avg_offset/=servers[best_index].num_responses;
        }

        /* cleanup */
        for(j=0; j<num_hosts; j++){ close(socklist[j]); }
        free(socklist);
        free(ufds);
        free(servers);
        free(req);
        freeaddrinfo(ai);

        if(verbose) printf("overall average offset: %.10g\n", avg_offset);
        return avg_offset;
}

int process_arguments(int argc, char **argv){
        int c;
        int option=0;
        static struct option longopts[] = {
                {"version", no_argument, 0, 'V'},
                {"help", no_argument, 0, 'h'},
                {"verbose", no_argument, 0, 'v'},
                {"use-ipv4", no_argument, 0, '4'},
                {"use-ipv6", no_argument, 0, '6'},
                {"quiet", no_argument, 0, 'q'},
                {"warning", required_argument, 0, 'w'},
                {"critical", required_argument, 0, 'c'},
                {"timeout", required_argument, 0, 't'},
                {"hostname", required_argument, 0, 'H'},
                {0, 0, 0, 0}
        };

        
        if (argc < 2)
                usage ("\n");

        while (1) {
                c = getopt_long (argc, argv, "Vhv46qw:c:t:H:", longopts, &option);
                if (c == -1 || c == EOF || c == 1)
                        break;

                switch (c) {
                case 'h':
                        print_help();
                        exit(STATE_OK);
                        break;
                case 'V':
                        print_revision(progname, revision);
                        exit(STATE_OK);
                        break;
                case 'v':
                        verbose++;
                        break;
                case 'q':
                        quiet = 1;
                        break;
                case 'w':
                        owarn = optarg;
                        break;
                case 'c':
                        ocrit = optarg;
                        break;
                case 'H':
                        if(is_host(optarg) == FALSE)
                                usage2(_("Invalid hostname/address"), optarg);
                        server_address = strdup(optarg);
                        break;
                case 't':
                        socket_timeout=atoi(optarg);
                        break;
                case '4':
                        address_family = AF_INET;
                        break;
                case '6':
#ifdef USE_IPV6
                        address_family = AF_INET6;
#else
                        usage4 (_("IPv6 support not available"));
#endif
                        break;
                case '?':
                        /* print short usage statement if args not parsable */
                        usage5 ();
                        break;
                }
        }

        if(server_address == NULL){
                usage4(_("Hostname was not supplied"));
        }

        return 0;
}

char *perfd_offset (double offset)
{
        return fperfdata ("offset", offset, "s",
                TRUE, offset_thresholds->warning->end,
                TRUE, offset_thresholds->critical->end,
                FALSE, 0, FALSE, 0);
}

int main(int argc, char *argv[]){
        int result, offset_result;
        double offset=0;
        char *result_line, *perfdata_line;

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

        result = offset_result = STATE_OK;

        /* Parse extra opts if any */
        argv=np_extra_opts (&argc, argv, progname);

        if (process_arguments (argc, argv) == ERROR)
                usage4 (_("Could not parse arguments"));

        set_thresholds(&offset_thresholds, owarn, ocrit);

        /* initialize alarm signal handling */
        signal (SIGALRM, socket_timeout_alarm_handler);

        /* set socket timeout */
        alarm (socket_timeout);

        offset = offset_request(server_address, &offset_result);
        if (offset_result == STATE_UNKNOWN) {
                result = (quiet == 1 ? STATE_UNKNOWN : STATE_CRITICAL);
        } else {
                result = get_status(fabs(offset), offset_thresholds);
        }

        switch (result) {
                case STATE_CRITICAL :
                        asprintf(&result_line, _("NTP CRITICAL:"));
                        break;
                case STATE_WARNING :
                        asprintf(&result_line, _("NTP WARNING:"));
                        break;
                case STATE_OK :
                        asprintf(&result_line, _("NTP OK:"));
                        break;
                default :
                        asprintf(&result_line, _("NTP UNKNOWN:"));
                        break;
        }
        if(offset_result == STATE_UNKNOWN){
                asprintf(&result_line, "%s %s", result_line, _("Offset unknown"));
                asprintf(&perfdata_line, "");
        } else {
                asprintf(&result_line, "%s %s %.10g secs", result_line, _("Offset"), offset);
                asprintf(&perfdata_line, "%s", perfd_offset(offset));
        }
        printf("%s|%s\n", result_line, perfdata_line);

        if(server_address!=NULL) free(server_address);
        return result;
}

void print_help(void){
        print_revision(progname, revision);

        printf ("Copyright (c) 2006 Sean Finney\n");
        printf (COPYRIGHT, copyright, email);

        printf ("%s\n", _("This plugin checks the clock offset with the ntp server"));

        printf ("\n\n");

        print_usage();
        printf (_(UT_HELP_VRSN));
        printf (_(UT_EXTRA_OPTS));
        printf (_(UT_HOST_PORT), 'p', "123");
        printf (" %s\n", "-q, --quiet");
        printf ("    %s\n", _("Returns UNKNOWN instead of CRITICAL if offset cannot be found"));
        printf (" %s\n", "-w, --warning=THRESHOLD");
        printf ("    %s\n", _("Offset to result in warning status (seconds)"));
        printf (" %s\n", "-c, --critical=THRESHOLD");
        printf ("    %s\n", _("Offset to result in critical status (seconds)"));
        printf (_(UT_TIMEOUT), DEFAULT_SOCKET_TIMEOUT);
        printf (_(UT_VERBOSE));

        printf("\n");
        printf("%s\n", _("This plugin checks the clock offset between the local host and a"));
        printf("%s\n", _("remote NTP server. It is independent of any commandline programs or"));
        printf("%s\n", _("external libraries."));

        printf("\n");
        printf("%s\n", _("Notes:"));
        printf(" %s\n", _("If you'd rather want to monitor an NTP server, please use"));
        printf(" %s\n", _("check_ntp_peer."));
        printf("\n");
        printf(_(UT_THRESHOLDS_NOTES));
#ifdef NP_EXTRA_OPTS
        printf("\n");
        printf(_(UT_EXTRA_OPTS_NOTES));
#endif

        printf("\n");
        printf("%s\n", _("Examples:"));
        printf("  %s\n", ("./check_ntp_time -H ntpserv -w 0.5 -c 1"));

        printf (_(UT_SUPPORT));
}

void
print_usage(void)
{
        printf (_("Usage:"));
        printf(" %s -H <host> [-w <warn>] [-c <crit>] [-v verbose]\n", progname);
}