diff options
Diffstat (limited to 'plugins/check_ntp_time.c')
-rw-r--r-- | plugins/check_ntp_time.c | 654 |
1 files changed, 654 insertions, 0 deletions
diff --git a/plugins/check_ntp_time.c b/plugins/check_ntp_time.c new file mode 100644 index 0000000..46cc604 --- /dev/null +++ b/plugins/check_ntp_time.c @@ -0,0 +1,654 @@ +/***************************************************************************** +* +* Monitoring check_ntp_time plugin +* +* License: GPL +* Copyright (c) 2006 Sean Finney <seanius@seanius.net> +* Copyright (c) 2006-2008 Monitoring Plugins Development Team +* +* 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/>. +* +* +*****************************************************************************/ + +const char *progname = "check_ntp_time"; +const char *copyright = "2006-2008"; +const char *email = "devel@monitoring-plugins.org"; + +#include "common.h" +#include "netutils.h" +#include "utils.h" + +static char *server_address=NULL; +static char *port="123"; +static int verbose=0; +static int quiet=0; +static char *owarn="60"; +static char *ocrit="120"; +static int time_offset=0; + +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. */ +#ifndef AVG_NUM +#define AVG_NUM 4 +#endif + +/* 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 received 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 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_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, port, &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)){ + /* don't die here, because it is enough if there is one server + answering in time. This also would break for dual ipv4/6 stacked + ntp servers when the client only supports on of them. + */ + DBG(printf("can't create socket connection on peer %i: %s\n", i, strerror(errno))); + } 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. */ + 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; + 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)+time_offset; + 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[i]; + } + 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'}, + {"time-offset", optional_argument, 0, 'o'}, + {"warning", required_argument, 0, 'w'}, + {"critical", required_argument, 0, 'c'}, + {"timeout", required_argument, 0, 't'}, + {"hostname", required_argument, 0, 'H'}, + {"port", required_argument, 0, 'p'}, + {0, 0, 0, 0} + }; + + + if (argc < 2) + usage ("\n"); + + while (1) { + c = getopt_long (argc, argv, "Vhv46qw:c:t:H:p:o:", longopts, &option); + if (c == -1 || c == EOF || c == 1) + break; + + switch (c) { + case 'h': + print_help(); + exit(STATE_UNKNOWN); + break; + case 'V': + print_revision(progname, NP_VERSION); + exit(STATE_UNKNOWN); + 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 'p': + port = strdup(optarg); + break; + case 't': + socket_timeout=atoi(optarg); + break; + case 'o': + time_offset=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 : + xasprintf(&result_line, _("NTP CRITICAL:")); + break; + case STATE_WARNING : + xasprintf(&result_line, _("NTP WARNING:")); + break; + case STATE_OK : + xasprintf(&result_line, _("NTP OK:")); + break; + default : + xasprintf(&result_line, _("NTP UNKNOWN:")); + break; + } + if(offset_result == STATE_UNKNOWN){ + xasprintf(&result_line, "%s %s", result_line, _("Offset unknown")); + xasprintf(&perfdata_line, ""); + } else { + xasprintf(&result_line, "%s %s %.10g secs", result_line, _("Offset"), offset); + xasprintf(&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, NP_VERSION); + + 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_IPv46); + 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 (" %s\n", "-o, --time_offset=INTEGER"); + printf (" %s\n", _("Expected offset of the ntp server relative to local server (seconds)")); + printf (UT_CONN_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(" %s\n", _("--time-offset is useful for compensating for servers with known")); + printf(" %s\n", _("and expected clock skew.")); + printf("\n"); + printf(UT_THRESHOLDS_NOTES); + + 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 ("%s\n", _("Usage:")); + printf(" %s -H <host> [-4|-6] [-w <warn>] [-c <crit>] [-v verbose] [-o <time offset>]\n", progname); +} + |