plugins/check_ntp_time.c

   1 /*****************************************************************************
   2 *
   3 * Nagios check_ntp_time plugin
   4 *
   5 * License: GPL
   6 * Copyright (c) 2006 Sean Finney <seanius@seanius.net>
   7 * Copyright (c) 2006-2008 Nagios Plugins Development Team
   8 *
   9 * Description:
  10 *
  11 * This file contains the check_ntp_time plugin
  12 *
  13 * This plugin checks the clock offset between the local host and a
  14 * remote NTP server. It is independent of any commandline programs or
  15 * external libraries.
  16 *
  17 * If you'd rather want to monitor an NTP server, please use
  18 * check_ntp_peer.
  19 *
  20 *
  21 * This program is free software: you can redistribute it and/or modify
  22 * it under the terms of the GNU General Public License as published by
  23 * the Free Software Foundation, either version 3 of the License, or
  24 * (at your option) any later version.
  25 *
  26 * This program is distributed in the hope that it will be useful,
  27 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  28 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  29 * GNU General Public License for more details.
  30 *
  31 * You should have received a copy of the GNU General Public License
  32 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  33 *
  34 *
  35 *****************************************************************************/
  36
  37 const char *progname = "check_ntp_time";
  38 const char *copyright = "2006-2008";
  39 const char *email = "nagiosplug-devel@lists.sourceforge.net";
  40
  41 #include "common.h"
  42 #include "netutils.h"
  43 #include "utils.h"
  44
  45 static char *server_address=NULL;
  46 static char *port="123";
  47 static int verbose=0;
  48 static int quiet=0;
  49 static char *owarn="60";
  50 static char *ocrit="120";
  51
  52 int process_arguments (int, char **);
  53 thresholds *offset_thresholds = NULL;
  54 void print_help (void);
  55 void print_usage (void);
  56
  57 /* number of times to perform each request to get a good average. */
  58 #define AVG_NUM 4
  59
  60 /* max size of control message data */
  61 #define MAX_CM_SIZE 468
  62
  63 /* this structure holds everything in an ntp request/response as per rfc1305 */
  64 typedef struct {
  65         uint8_t flags;       /* byte with leapindicator,vers,mode. see macros */
  66         uint8_t stratum;     /* clock stratum */
  67         int8_t poll;         /* polling interval */
  68         int8_t precision;    /* precision of the local clock */
  69         int32_t rtdelay;     /* total rt delay, as a fixed point num. see macros */
  70         uint32_t rtdisp;     /* like above, but for max err to primary src */
  71         uint32_t refid;      /* ref clock identifier */
  72         uint64_t refts;      /* reference timestamp.  local time local clock */
  73         uint64_t origts;     /* time at which request departed client */
  74         uint64_t rxts;       /* time at which request arrived at server */
  75         uint64_t txts;       /* time at which request departed server */
  76 } ntp_message;
  77
  78 /* this structure holds data about results from querying offset from a peer */
  79 typedef struct {
  80         time_t waiting;         /* ts set when we started waiting for a response */
  81         int num_responses;      /* number of successfully recieved responses */
  82         uint8_t stratum;        /* copied verbatim from the ntp_message */
  83         double rtdelay;         /* converted from the ntp_message */
  84         double rtdisp;          /* converted from the ntp_message */
  85         double offset[AVG_NUM]; /* offsets from each response */
  86         uint8_t flags;       /* byte with leapindicator,vers,mode. see macros */
  87 } ntp_server_results;
  88
  89 /* bits 1,2 are the leap indicator */
  90 #define LI_MASK 0xc0
  91 #define LI(x) ((x&LI_MASK)>>6)
  92 #define LI_SET(x,y) do{ x |= ((y<<6)&LI_MASK); }while(0)
  93 /* and these are the values of the leap indicator */
  94 #define LI_NOWARNING 0x00
  95 #define LI_EXTRASEC 0x01
  96 #define LI_MISSINGSEC 0x02
  97 #define LI_ALARM 0x03
  98 /* bits 3,4,5 are the ntp version */
  99 #define VN_MASK 0x38
 100 #define VN(x)   ((x&VN_MASK)>>3)
 101 #define VN_SET(x,y)     do{ x |= ((y<<3)&VN_MASK); }while(0)
 102 #define VN_RESERVED 0x02
 103 /* bits 6,7,8 are the ntp mode */
 104 #define MODE_MASK 0x07
 105 #define MODE(x) (x&MODE_MASK)
 106 #define MODE_SET(x,y)   do{ x |= (y&MODE_MASK); }while(0)
 107 /* here are some values */
 108 #define MODE_CLIENT 0x03
 109 #define MODE_CONTROLMSG 0x06
 110 /* In control message, bits 8-10 are R,E,M bits */
 111 #define REM_MASK 0xe0
 112 #define REM_RESP 0x80
 113 #define REM_ERROR 0x40
 114 #define REM_MORE 0x20
 115 /* In control message, bits 11 - 15 are opcode */
 116 #define OP_MASK 0x1f
 117 #define OP_SET(x,y)   do{ x |= (y&OP_MASK); }while(0)
 118 #define OP_READSTAT 0x01
 119 #define OP_READVAR  0x02
 120 /* In peer status bytes, bits 6,7,8 determine clock selection status */
 121 #define PEER_SEL(x) ((ntohs(x)>>8)&0x07)
 122 #define PEER_INCLUDED 0x04
 123 #define PEER_SYNCSOURCE 0x06
 124
 125 /**
 126  ** a note about the 32-bit "fixed point" numbers:
 127  **
 128  they are divided into halves, each being a 16-bit int in network byte order:
 129  - the first 16 bits are an int on the left side of a decimal point.
 130  - the second 16 bits represent a fraction n/(2^16)
 131  likewise for the 64-bit "fixed point" numbers with everything doubled :)
 132  **/
 133
 134 /* macros to access the left/right 16 bits of a 32-bit ntp "fixed point"
 135    number.  note that these can be used as lvalues too */
 136 #define L16(x) (((uint16_t*)&x)[0])
 137 #define R16(x) (((uint16_t*)&x)[1])
 138 /* macros to access the left/right 32 bits of a 64-bit ntp "fixed point"
 139    number.  these too can be used as lvalues */
 140 #define L32(x) (((uint32_t*)&x)[0])
 141 #define R32(x) (((uint32_t*)&x)[1])
 142
 143 /* ntp wants seconds since 1/1/00, epoch is 1/1/70.  this is the difference */
 144 #define EPOCHDIFF 0x83aa7e80UL
 145
 146 /* extract a 32-bit ntp fixed point number into a double */
 147 #define NTP32asDOUBLE(x) (ntohs(L16(x)) + (double)ntohs(R16(x))/65536.0)
 148
 149 /* likewise for a 64-bit ntp fp number */
 150 #define NTP64asDOUBLE(n) (double)(((uint64_t)n)?\
 151                          (ntohl(L32(n))-EPOCHDIFF) + \
 152                          (.00000001*(0.5+(double)(ntohl(R32(n))/42.94967296))):\
 153                          0)
 154
 155 /* convert a struct timeval to a double */
 156 #define TVasDOUBLE(x) (double)(x.tv_sec+(0.000001*x.tv_usec))
 157
 158 /* convert an ntp 64-bit fp number to a struct timeval */
 159 #define NTP64toTV(n,t) \
 160         do{ if(!n) t.tv_sec = t.tv_usec = 0; \
 161             else { \
 162                         t.tv_sec=ntohl(L32(n))-EPOCHDIFF; \
 163                         t.tv_usec=(int)(0.5+(double)(ntohl(R32(n))/4294.967296)); \
 164                 } \
 165         }while(0)
 166
 167 /* convert a struct timeval to an ntp 64-bit fp number */
 168 #define TVtoNTP64(t,n) \
 169         do{ if(!t.tv_usec && !t.tv_sec) n=0x0UL; \
 170                 else { \
 171                         L32(n)=htonl(t.tv_sec + EPOCHDIFF); \
 172                         R32(n)=htonl((uint64_t)((4294.967296*t.tv_usec)+.5)); \
 173                 } \
 174         } while(0)
 175
 176 /* NTP control message header is 12 bytes, plus any data in the data
 177  * field, plus null padding to the nearest 32-bit boundary per rfc.
 178  */
 179 #define SIZEOF_NTPCM(m) (12+ntohs(m.count)+((m.count)?4-(ntohs(m.count)%4):0))
 180
 181 /* finally, a little helper or two for debugging: */
 182 #define DBG(x) do{if(verbose>1){ x; }}while(0);
 183 #define PRINTSOCKADDR(x) \
 184         do{ \
 185                 printf("%u.%u.%u.%u", (x>>24)&0xff, (x>>16)&0xff, (x>>8)&0xff, x&0xff);\
 186         }while(0);
 187
 188 /* calculate the offset of the local clock */
 189 static inline double calc_offset(const ntp_message *m, const struct timeval *t){
 190         double client_tx, peer_rx, peer_tx, client_rx;
 191         client_tx = NTP64asDOUBLE(m->origts);
 192         peer_rx = NTP64asDOUBLE(m->rxts);
 193         peer_tx = NTP64asDOUBLE(m->txts);
 194         client_rx=TVasDOUBLE((*t));
 195         return (.5*((peer_tx-client_rx)+(peer_rx-client_tx)));
 196 }
 197
 198 /* print out a ntp packet in human readable/debuggable format */
 199 void print_ntp_message(const ntp_message *p){
 200         struct timeval ref, orig, rx, tx;
 201
 202         NTP64toTV(p->refts,ref);
 203         NTP64toTV(p->origts,orig);
 204         NTP64toTV(p->rxts,rx);
 205         NTP64toTV(p->txts,tx);
 206
 207         printf("packet contents:\n");
 208         printf("\tflags: 0x%.2x\n", p->flags);
 209         printf("\t  li=%d (0x%.2x)\n", LI(p->flags), p->flags&LI_MASK);
 210         printf("\t  vn=%d (0x%.2x)\n", VN(p->flags), p->flags&VN_MASK);
 211         printf("\t  mode=%d (0x%.2x)\n", MODE(p->flags), p->flags&MODE_MASK);
 212         printf("\tstratum = %d\n", p->stratum);
 213         printf("\tpoll = %g\n", pow(2, p->poll));
 214         printf("\tprecision = %g\n", pow(2, p->precision));
 215         printf("\trtdelay = %-.16g\n", NTP32asDOUBLE(p->rtdelay));
 216         printf("\trtdisp = %-.16g\n", NTP32asDOUBLE(p->rtdisp));
 217         printf("\trefid = %x\n", p->refid);
 218         printf("\trefts = %-.16g\n", NTP64asDOUBLE(p->refts));
 219         printf("\torigts = %-.16g\n", NTP64asDOUBLE(p->origts));
 220         printf("\trxts = %-.16g\n", NTP64asDOUBLE(p->rxts));
 221         printf("\ttxts = %-.16g\n", NTP64asDOUBLE(p->txts));
 222 }
 223
 224 void setup_request(ntp_message *p){
 225         struct timeval t;
 226
 227         memset(p, 0, sizeof(ntp_message));
 228         LI_SET(p->flags, LI_ALARM);
 229         VN_SET(p->flags, 4);
 230         MODE_SET(p->flags, MODE_CLIENT);
 231         p->poll=4;
 232         p->precision=(int8_t)0xfa;
 233         L16(p->rtdelay)=htons(1);
 234         L16(p->rtdisp)=htons(1);
 235
 236         gettimeofday(&t, NULL);
 237         TVtoNTP64(t,p->txts);
 238 }
 239
 240 /* select the "best" server from a list of servers, and return its index.
 241  * this is done by filtering servers based on stratum, dispersion, and
 242  * finally round-trip delay. */
 243 int best_offset_server(const ntp_server_results *slist, int nservers){
 244         int i=0, cserver=0, best_server=-1;
 245
 246         /* for each server */
 247         for(cserver=0; cserver<nservers; cserver++){
 248                 /* We don't want any servers that fails these tests */
 249                 /* Sort out servers that didn't respond or responede with a 0 stratum;
 250                  * stratum 0 is for reference clocks so no NTP server should ever report
 251                  * a stratum 0 */
 252                 if ( slist[cserver].stratum == 0){
 253                         if (verbose) printf("discarding peer %d: stratum=%d\n", cserver, slist[cserver].stratum);
 254                         continue;
 255                 }
 256                 /* Sort out servers with error flags */
 257                 if ( LI(slist[cserver].flags) == LI_ALARM ){
 258                         if (verbose) printf("discarding peer %d: flags=%d\n", cserver, LI(slist[cserver].flags));
 259                         continue;
 260                 }
 261
 262                 /* If we don't have a server yet, use the first one */
 263                 if (best_server == -1) {
 264                         best_server = cserver;
 265                         DBG(printf("using peer %d as our first candidate\n", best_server));
 266                         continue;
 267                 }
 268
 269                 /* compare the server to the best one we've seen so far */
 270                 /* does it have an equal or better stratum? */
 271                 DBG(printf("comparing peer %d with peer %d\n", cserver, best_server));
 272                 if(slist[cserver].stratum <= slist[best_server].stratum){
 273                         DBG(printf("stratum for peer %d <= peer %d\n", cserver, best_server));
 274                         /* does it have an equal or better dispersion? */
 275                         if(slist[cserver].rtdisp <= slist[best_server].rtdisp){
 276                                 DBG(printf("dispersion for peer %d <= peer %d\n", cserver, best_server));
 277                                 /* does it have a better rtdelay? */
 278                                 if(slist[cserver].rtdelay < slist[best_server].rtdelay){
 279                                         DBG(printf("rtdelay for peer %d < peer %d\n", cserver, best_server));
 280                                         best_server = cserver;
 281                                         DBG(printf("peer %d is now our best candidate\n", best_server));
 282                                 }
 283                         }
 284                 }
 285         }
 286
 287         if(best_server >= 0) {
 288                 DBG(printf("best server selected: peer %d\n", best_server));
 289                 return best_server;
 290         } else {
 291                 DBG(printf("no peers meeting synchronization criteria :(\n"));
 292                 return -1;
 293         }
 294 }
 295
 296 /* do everything we need to get the total average offset
 297  * - we use a certain amount of parallelization with poll() to ensure
 298  *   we don't waste time sitting around waiting for single packets.
 299  * - we also "manually" handle resolving host names and connecting, because
 300  *   we have to do it in a way that our lazy macros don't handle currently :( */
 301 double offset_request(const char *host, int *status){
 302         int i=0, j=0, ga_result=0, num_hosts=0, *socklist=NULL, respnum=0;
 303         int servers_completed=0, one_written=0, one_read=0, servers_readable=0, best_index=-1;
 304         time_t now_time=0, start_ts=0;
 305         ntp_message *req=NULL;
 306         double avg_offset=0.;
 307         struct timeval recv_time;
 308         struct addrinfo *ai=NULL, *ai_tmp=NULL, hints;
 309         struct pollfd *ufds=NULL;
 310         ntp_server_results *servers=NULL;
 311
 312         /* setup hints to only return results from getaddrinfo that we'd like */
 313         memset(&hints, 0, sizeof(struct addrinfo));
 314         hints.ai_family = address_family;
 315         hints.ai_protocol = IPPROTO_UDP;
 316         hints.ai_socktype = SOCK_DGRAM;
 317
 318         /* fill in ai with the list of hosts resolved by the host name */
 319         ga_result = getaddrinfo(host, port, &hints, &ai);
 320         if(ga_result!=0){
 321                 die(STATE_UNKNOWN, "error getting address for %s: %s\n",
 322                     host, gai_strerror(ga_result));
 323         }
 324
 325         /* count the number of returned hosts, and allocate stuff accordingly */
 326         for(ai_tmp=ai; ai_tmp!=NULL; ai_tmp=ai_tmp->ai_next){ num_hosts++; }
 327         req=(ntp_message*)malloc(sizeof(ntp_message)*num_hosts);
 328         if(req==NULL) die(STATE_UNKNOWN, "can not allocate ntp message array");
 329         socklist=(int*)malloc(sizeof(int)*num_hosts);
 330         if(socklist==NULL) die(STATE_UNKNOWN, "can not allocate socket array");
 331         ufds=(struct pollfd*)malloc(sizeof(struct pollfd)*num_hosts);
 332         if(ufds==NULL) die(STATE_UNKNOWN, "can not allocate socket array");
 333         servers=(ntp_server_results*)malloc(sizeof(ntp_server_results)*num_hosts);
 334         if(servers==NULL) die(STATE_UNKNOWN, "can not allocate server array");
 335         memset(servers, 0, sizeof(ntp_server_results)*num_hosts);
 336         DBG(printf("Found %d peers to check\n", num_hosts));
 337
 338         /* setup each socket for writing, and the corresponding struct pollfd */
 339         ai_tmp=ai;
 340         for(i=0;ai_tmp;i++){
 341                 socklist[i]=socket(ai_tmp->ai_family, SOCK_DGRAM, IPPROTO_UDP);
 342                 if(socklist[i] == -1) {
 343                         perror(NULL);
 344                         die(STATE_UNKNOWN, "can not create new socket");
 345                 }
 346                 if(connect(socklist[i], ai_tmp->ai_addr, ai_tmp->ai_addrlen)){
 347                         die(STATE_UNKNOWN, "can't create socket connection");
 348                 } else {
 349                         ufds[i].fd=socklist[i];
 350                         ufds[i].events=POLLIN;
 351                         ufds[i].revents=0;
 352                 }
 353                 ai_tmp = ai_tmp->ai_next;
 354         }
 355
 356         /* now do AVG_NUM checks to each host. We stop before timeout/2 seconds
 357          * have passed in order to ensure post-processing and jitter time. */
 358         now_time=start_ts=time(NULL);
 359         while(servers_completed<num_hosts && now_time-start_ts <= socket_timeout/2){
 360                 /* loop through each server and find each one which hasn't
 361                  * been touched in the past second or so and is still lacking
 362                  * some responses. For each of these servers, send a new request,
 363                  * and update the "waiting" timestamp with the current time. */
 364                 one_written=0;
 365                 now_time=time(NULL);
 366
 367                 for(i=0; i<num_hosts; i++){
 368                         if(servers[i].waiting<now_time && servers[i].num_responses<AVG_NUM){
 369                                 if(verbose && servers[i].waiting != 0) printf("re-");
 370                                 if(verbose) printf("sending request to peer %d\n", i);
 371                                 setup_request(&req[i]);
 372                                 write(socklist[i], &req[i], sizeof(ntp_message));
 373                                 servers[i].waiting=now_time;
 374                                 one_written=1;
 375                                 break;
 376                         }
 377                 }
 378
 379                 /* quickly poll for any sockets with pending data */
 380                 servers_readable=poll(ufds, num_hosts, 100);
 381                 if(servers_readable==-1){
 382                         perror("polling ntp sockets");
 383                         die(STATE_UNKNOWN, "communication errors");
 384                 }
 385
 386                 /* read from any sockets with pending data */
 387                 for(i=0; servers_readable && i<num_hosts; i++){
 388                         if(ufds[i].revents&POLLIN && servers[i].num_responses < AVG_NUM){
 389                                 if(verbose) {
 390                                         printf("response from peer %d: ", i);
 391                                 }
 392
 393                                 read(ufds[i].fd, &req[i], sizeof(ntp_message));
 394                                 gettimeofday(&recv_time, NULL);
 395                                 DBG(print_ntp_message(&req[i]));
 396                                 respnum=servers[i].num_responses++;
 397                                 servers[i].offset[respnum]=calc_offset(&req[i], &recv_time);
 398                                 if(verbose) {
 399                                         printf("offset %.10g\n", servers[i].offset[respnum]);
 400                                 }
 401                                 servers[i].stratum=req[i].stratum;
 402                                 servers[i].rtdisp=NTP32asDOUBLE(req[i].rtdisp);
 403                                 servers[i].rtdelay=NTP32asDOUBLE(req[i].rtdelay);
 404                                 servers[i].waiting=0;
 405                                 servers[i].flags=req[i].flags;
 406                                 servers_readable--;
 407                                 one_read = 1;
 408                                 if(servers[i].num_responses==AVG_NUM) servers_completed++;
 409                         }
 410                 }
 411                 /* lather, rinse, repeat. */
 412         }
 413
 414         if (one_read == 0) {
 415                 die(STATE_CRITICAL, "NTP CRITICAL: No response from NTP server\n");
 416         }
 417
 418         /* now, pick the best server from the list */
 419         best_index=best_offset_server(servers, num_hosts);
 420         if(best_index < 0){
 421                 *status=STATE_UNKNOWN;
 422         } else {
 423                 /* finally, calculate the average offset */
 424                 for(i=0; i<servers[best_index].num_responses;i++){
 425                         avg_offset+=servers[best_index].offset[j];
 426                 }
 427                 avg_offset/=servers[best_index].num_responses;
 428         }
 429
 430         /* cleanup */
 431         for(j=0; j<num_hosts; j++){ close(socklist[j]); }
 432         free(socklist);
 433         free(ufds);
 434         free(servers);
 435         free(req);
 436         freeaddrinfo(ai);
 437
 438         if(verbose) printf("overall average offset: %.10g\n", avg_offset);
 439         return avg_offset;
 440 }
 441
 442 int process_arguments(int argc, char **argv){
 443         int c;
 444         int option=0;
 445         static struct option longopts[] = {
 446                 {"version", no_argument, 0, 'V'},
 447                 {"help", no_argument, 0, 'h'},
 448                 {"verbose", no_argument, 0, 'v'},
 449                 {"use-ipv4", no_argument, 0, '4'},
 450                 {"use-ipv6", no_argument, 0, '6'},
 451                 {"quiet", no_argument, 0, 'q'},
 452                 {"warning", required_argument, 0, 'w'},
 453                 {"critical", required_argument, 0, 'c'},
 454                 {"timeout", required_argument, 0, 't'},
 455                 {"hostname", required_argument, 0, 'H'},
 456                 {"port", required_argument, 0, 'p'},
 457                 {0, 0, 0, 0}
 458         };
 459
 460
 461         if (argc < 2)
 462                 usage ("\n");
 463
 464         while (1) {
 465                 c = getopt_long (argc, argv, "Vhv46qw:c:t:H:p:", longopts, &option);
 466                 if (c == -1 || c == EOF || c == 1)
 467                         break;
 468
 469                 switch (c) {
 470                 case 'h':
 471                         print_help();
 472                         exit(STATE_OK);
 473                         break;
 474                 case 'V':
 475                         print_revision(progname, NP_VERSION);
 476                         exit(STATE_OK);
 477                         break;
 478                 case 'v':
 479                         verbose++;
 480                         break;
 481                 case 'q':
 482                         quiet = 1;
 483                         break;
 484                 case 'w':
 485                         owarn = optarg;
 486                         break;
 487                 case 'c':
 488                         ocrit = optarg;
 489                         break;
 490                 case 'H':
 491                         if(is_host(optarg) == FALSE)
 492                                 usage2(_("Invalid hostname/address"), optarg);
 493                         server_address = strdup(optarg);
 494                         break;
 495                 case 'p':
 496                         port = strdup(optarg);
 497                         break;
 498                 case 't':
 499                         socket_timeout=atoi(optarg);
 500                         break;
 501                 case '4':
 502                         address_family = AF_INET;
 503                         break;
 504                 case '6':
 505 #ifdef USE_IPV6
 506                         address_family = AF_INET6;
 507 #else
 508                         usage4 (_("IPv6 support not available"));
 509 #endif
 510                         break;
 511                 case '?':
 512                         /* print short usage statement if args not parsable */
 513                         usage5 ();
 514                         break;
 515                 }
 516         }
 517
 518         if(server_address == NULL){
 519                 usage4(_("Hostname was not supplied"));
 520         }
 521
 522         return 0;
 523 }
 524
 525 char *perfd_offset (double offset)
 526 {
 527         return fperfdata ("offset", offset, "s",
 528                 TRUE, offset_thresholds->warning->end,
 529                 TRUE, offset_thresholds->critical->end,
 530                 FALSE, 0, FALSE, 0);
 531 }
 532
 533 int main(int argc, char *argv[]){
 534         int result, offset_result;
 535         double offset=0;
 536         char *result_line, *perfdata_line;
 537
 538         setlocale (LC_ALL, "");
 539         bindtextdomain (PACKAGE, LOCALEDIR);
 540         textdomain (PACKAGE);
 541
 542         result = offset_result = STATE_OK;
 543
 544         /* Parse extra opts if any */
 545         argv=np_extra_opts (&argc, argv, progname);
 546
 547         if (process_arguments (argc, argv) == ERROR)
 548                 usage4 (_("Could not parse arguments"));
 549
 550         set_thresholds(&offset_thresholds, owarn, ocrit);
 551
 552         /* initialize alarm signal handling */
 553         signal (SIGALRM, socket_timeout_alarm_handler);
 554
 555         /* set socket timeout */
 556         alarm (socket_timeout);
 557
 558         offset = offset_request(server_address, &offset_result);
 559         if (offset_result == STATE_UNKNOWN) {
 560                 result = (quiet == 1 ? STATE_UNKNOWN : STATE_CRITICAL);
 561         } else {
 562                 result = get_status(fabs(offset), offset_thresholds);
 563         }
 564
 565         switch (result) {
 566                 case STATE_CRITICAL :
 567                         asprintf(&result_line, _("NTP CRITICAL:"));
 568                         break;
 569                 case STATE_WARNING :
 570                         asprintf(&result_line, _("NTP WARNING:"));
 571                         break;
 572                 case STATE_OK :
 573                         asprintf(&result_line, _("NTP OK:"));
 574                         break;
 575                 default :
 576                         asprintf(&result_line, _("NTP UNKNOWN:"));
 577                         break;
 578         }
 579         if(offset_result == STATE_UNKNOWN){
 580                 asprintf(&result_line, "%s %s", result_line, _("Offset unknown"));
 581                 asprintf(&perfdata_line, "");
 582         } else {
 583                 asprintf(&result_line, "%s %s %.10g secs", result_line, _("Offset"), offset);
 584                 asprintf(&perfdata_line, "%s", perfd_offset(offset));
 585         }
 586         printf("%s|%s\n", result_line, perfdata_line);
 587
 588         if(server_address!=NULL) free(server_address);
 589         return result;
 590 }
 591
 592 void print_help(void){
 593         print_revision(progname, NP_VERSION);
 594
 595         printf ("Copyright (c) 2006 Sean Finney\n");
 596         printf (COPYRIGHT, copyright, email);
 597
 598         printf ("%s\n", _("This plugin checks the clock offset with the ntp server"));
 599
 600         printf ("\n\n");
 601
 602         print_usage();
 603         printf (_(UT_HELP_VRSN));
 604         printf (_(UT_EXTRA_OPTS));
 605         printf (_(UT_HOST_PORT), 'p', "123");
 606         printf (" %s\n", "-q, --quiet");
 607         printf ("    %s\n", _("Returns UNKNOWN instead of CRITICAL if offset cannot be found"));
 608         printf (" %s\n", "-w, --warning=THRESHOLD");
 609         printf ("    %s\n", _("Offset to result in warning status (seconds)"));
 610         printf (" %s\n", "-c, --critical=THRESHOLD");
 611         printf ("    %s\n", _("Offset to result in critical status (seconds)"));
 612         printf (_(UT_TIMEOUT), DEFAULT_SOCKET_TIMEOUT);
 613         printf (_(UT_VERBOSE));
 614
 615         printf("\n");
 616         printf("%s\n", _("This plugin checks the clock offset between the local host and a"));
 617         printf("%s\n", _("remote NTP server. It is independent of any commandline programs or"));
 618         printf("%s\n", _("external libraries."));
 619
 620         printf("\n");
 621         printf("%s\n", _("Notes:"));
 622         printf(" %s\n", _("If you'd rather want to monitor an NTP server, please use"));
 623         printf(" %s\n", _("check_ntp_peer."));
 624         printf("\n");
 625         printf(_(UT_THRESHOLDS_NOTES));
 626 #ifdef NP_EXTRA_OPTS
 627         printf("\n");
 628         printf(_(UT_EXTRA_OPTS_NOTES));
 629 #endif
 630
 631         printf("\n");
 632         printf("%s\n", _("Examples:"));
 633         printf("  %s\n", ("./check_ntp_time -H ntpserv -w 0.5 -c 1"));
 634
 635         printf (_(UT_SUPPORT));
 636 }
 637
 638 void
 639 print_usage(void)
 640 {
 641         printf (_("Usage:"));
 642         printf(" %s -H <host> [-w <warn>] [-c <crit>] [-v verbose]\n", progname);
 643 }
 644