/*****************************************************************************
 *
 * Monitoring check_ntp_peer plugin
 *
 * License: GPL
 * Copyright (c) 2006 Sean Finney <seanius@seanius.net>
 * Copyright (c) 2006-2024 Monitoring Plugins Development Team
 *
 * Description:
 *
 * This file contains the check_ntp_peer plugin
 *
 * This plugin checks an NTP server independent of any commandline
 * programs or external libraries.
 *
 * Use this plugin to check the health of an NTP server. It supports
 * checking the offset with the sync peer, the jitter and stratum. This
 * plugin will not check the clock offset between the local host and NTP
 * server; please use check_ntp_time for that purpose.
 *
 *
 * 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_peer";
const char *copyright = "2006-2024";
const char *email = "devel@monitoring-plugins.org";

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

static char *server_address = NULL;
static int port = 123;
static int verbose = 0;
static bool quiet = false;
static char *owarn = "60";
static char *ocrit = "120";
static bool do_stratum = false;
static char *swarn = "-1:16";
static char *scrit = "-1:16";
static bool do_jitter = false;
static char *jwarn = "-1:5000";
static char *jcrit = "-1:10000";
static bool do_truechimers = false;
static char *twarn = "0:";
static char *tcrit = "0:";
static bool syncsource_found = false;
static bool li_alarm = false;

static int process_arguments(int /*argc*/, char ** /*argv*/);
static thresholds *offset_thresholds = NULL;
static thresholds *jitter_thresholds = NULL;
static thresholds *stratum_thresholds = NULL;
static thresholds *truechimer_thresholds = NULL;
static void print_help(void);
void print_usage(void);

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

/* this structure holds everything in an ntp control message as per rfc1305 */
typedef struct {
	uint8_t flags;          /* byte with leapindicator,vers,mode. see macros */
	uint8_t op;             /* R,E,M bits and Opcode */
	uint16_t seq;           /* Packet sequence */
	uint16_t status;        /* Clock status */
	uint16_t assoc;         /* Association */
	uint16_t offset;        /* Similar to TCP sequence # */
	uint16_t count;         /* # bytes of data */
	char data[MAX_CM_SIZE]; /* ASCII data of the request */
							/* NB: not necessarily NULL terminated! */
} ntp_control_message;

/* this is an association/status-word pair found in control packet responses */
typedef struct {
	uint16_t assoc;
	uint16_t status;
} ntp_assoc_status_pair;

/* 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_TRUECHIMER 0x02
#define PEER_INCLUDED   0x04
#define PEER_SYNCSOURCE 0x06

/* 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) + ((ntohs(m.count) % 4) ? 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);

void print_ntp_control_message(const ntp_control_message *p) {
	printf("control packet contents:\n");
	printf("\tflags: 0x%.2x , 0x%.2x\n", p->flags, p->op);
	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("\t  response=%d (0x%.2x)\n", (p->op & REM_RESP) > 0, p->op & REM_RESP);
	printf("\t  more=%d (0x%.2x)\n", (p->op & REM_MORE) > 0, p->op & REM_MORE);
	printf("\t  error=%d (0x%.2x)\n", (p->op & REM_ERROR) > 0, p->op & REM_ERROR);
	printf("\t  op=%d (0x%.2x)\n", p->op & OP_MASK, p->op & OP_MASK);
	printf("\tsequence: %d (0x%.2x)\n", ntohs(p->seq), ntohs(p->seq));
	printf("\tstatus: %d (0x%.2x)\n", ntohs(p->status), ntohs(p->status));
	printf("\tassoc: %d (0x%.2x)\n", ntohs(p->assoc), ntohs(p->assoc));
	printf("\toffset: %d (0x%.2x)\n", ntohs(p->offset), ntohs(p->offset));
	printf("\tcount: %d (0x%.2x)\n", ntohs(p->count), ntohs(p->count));

	int numpeers = ntohs(p->count) / (sizeof(ntp_assoc_status_pair));
	if (p->op & REM_RESP && p->op & OP_READSTAT) {
		const ntp_assoc_status_pair *peer = (ntp_assoc_status_pair *)p->data;
		for (int i = 0; i < numpeers; i++) {
			printf("\tpeer id %.2x status %.2x", ntohs(peer[i].assoc), ntohs(peer[i].status));
			if (PEER_SEL(peer[i].status) >= PEER_SYNCSOURCE) {
				printf(" <-- current sync source");
			} else if (PEER_SEL(peer[i].status) >= PEER_INCLUDED) {
				printf(" <-- current sync candidate");
			} else if (PEER_SEL(peer[i].status) >= PEER_TRUECHIMER) {
				printf(" <-- outlyer, but truechimer");
			}
			printf("\n");
		}
	}
}

void setup_control_request(ntp_control_message *p, uint8_t opcode, uint16_t seq) {
	memset(p, 0, sizeof(ntp_control_message));
	LI_SET(p->flags, LI_NOWARNING);
	VN_SET(p->flags, VN_RESERVED);
	MODE_SET(p->flags, MODE_CONTROLMSG);
	OP_SET(p->op, opcode);
	p->seq = htons(seq);
	/* Remaining fields are zero for requests */
}

/* This function does all the actual work; roughly here's what it does
 * beside setting the offset, jitter and stratum passed as argument:
 *  - offset can be negative, so if it cannot get the offset, offset_result
 *    is set to UNKNOWN, otherwise OK.
 *  - jitter and stratum are set to -1 if they cannot be retrieved so any
 *    positive value means a success retrieving the value.
 *  - status is set to WARNING if there's no sync.peer (otherwise OK) and is
 *    the return value of the function.
 *  status is pretty much useless as syncsource_found is a global variable
 *  used later in main to check is the server was synchronized. It works
 *  so I left it alone */
int ntp_request(double *offset, int *offset_result, double *jitter, int *stratum, int *num_truechimers) {
	*offset_result = STATE_UNKNOWN;
	*jitter = *stratum = -1;
	*num_truechimers = 0;

	/* Long-winded explanation:
	 * Getting the sync peer offset, jitter and stratum requires a number of
	 * steps:
	 * 1) Send a READSTAT request.
	 * 2) Interpret the READSTAT reply
	 *  a) The data section contains a list of peer identifiers (16 bits)
	 *     and associated status words (16 bits)
	 *  b) We want the value of 0x06 in the SEL (peer selection) value,
	 *     which means "current synchronizatin source".  If that's missing,
	 *     we take anything better than 0x04 (see the rfc for details) but
	 *     set a minimum of warning.
	 * 3) Send a READVAR request for information on each peer identified
	 *    in 2b greater than the minimum selection value.
	 * 4) Extract the offset, jitter and stratum value from the data[]
	 *    (it's ASCII)
	 */
	int min_peer_sel = PEER_INCLUDED;
	int num_candidates = 0;
	void *tmp;
	ntp_assoc_status_pair *peers = NULL;
	int peer_offset = 0;
	int peers_size = 0;
	int npeers = 0;
	int conn = -1;
	my_udp_connect(server_address, port, &conn);

	/* keep sending requests until the server stops setting the
	 * REM_MORE bit, though usually this is only 1 packet. */
	ntp_control_message req;
	do {
		setup_control_request(&req, OP_READSTAT, 1);
		DBG(printf("sending READSTAT request"));
		write(conn, &req, SIZEOF_NTPCM(req));
		DBG(print_ntp_control_message(&req));

		do {
			/* Attempt to read the largest size packet possible */
			req.count = htons(MAX_CM_SIZE);
			DBG(printf("receiving READSTAT response"))
			if (read(conn, &req, SIZEOF_NTPCM(req)) == -1)
				die(STATE_CRITICAL, "NTP CRITICAL: No response from NTP server\n");
			DBG(print_ntp_control_message(&req));
			/* discard obviously invalid packets */
			if (ntohs(req.count) > MAX_CM_SIZE)
				die(STATE_CRITICAL, "NTP CRITICAL: Invalid packet received from NTP server\n");
		} while (!(req.op & OP_READSTAT && ntohs(req.seq) == 1));

		if (LI(req.flags) == LI_ALARM)
			li_alarm = true;
		/* Each peer identifier is 4 bytes in the data section, which
		 * we represent as a ntp_assoc_status_pair datatype.
		 */
		peers_size += ntohs(req.count);
		if ((tmp = realloc(peers, peers_size)) == NULL)
			free(peers), die(STATE_UNKNOWN, "can not (re)allocate 'peers' buffer\n");
		peers = tmp;
		memcpy((void *)((ptrdiff_t)peers + peer_offset), (void *)req.data, ntohs(req.count));
		npeers = peers_size / sizeof(ntp_assoc_status_pair);
		peer_offset += ntohs(req.count);
	} while (req.op & REM_MORE);

	/* first, let's find out if we have a sync source, or if there are
	 * at least some candidates. In the latter case we'll issue
	 * a warning but go ahead with the check on them. */
	for (int i = 0; i < npeers; i++) {
		if (PEER_SEL(peers[i].status) >= PEER_TRUECHIMER) {
			(*num_truechimers)++;
			if (PEER_SEL(peers[i].status) >= PEER_INCLUDED) {
				num_candidates++;
				if (PEER_SEL(peers[i].status) >= PEER_SYNCSOURCE) {
					syncsource_found = true;
					min_peer_sel = PEER_SYNCSOURCE;
				}
			}
		}
	}

	if (verbose)
		printf("%d candidate peers available\n", num_candidates);
	if (verbose && syncsource_found)
		printf("synchronization source found\n");

	int status = STATE_OK;
	if (!syncsource_found) {
		status = STATE_WARNING;
		if (verbose)
			printf("warning: no synchronization source found\n");
	}
	if (li_alarm) {
		status = STATE_WARNING;
		if (verbose)
			printf("warning: LI_ALARM bit is set\n");
	}

	const char *getvar = "stratum,offset,jitter";
	char *data;
	for (int i = 0; i < npeers; i++) {
		/* Only query this server if it is the current sync source */
		/* If there's no sync.peer, query all candidates and use the best one */
		if (PEER_SEL(peers[i].status) >= min_peer_sel) {
			if (verbose)
				printf("Getting offset, jitter and stratum for peer %.2x\n", ntohs(peers[i].assoc));
			xasprintf(&data, "");
			do {
				setup_control_request(&req, OP_READVAR, 2);
				req.assoc = peers[i].assoc;
				/* Putting the wanted variable names in the request
				 * cause the server to provide _only_ the requested values.
				 * thus reducing net traffic, guaranteeing us only a single
				 * datagram in reply, and making interpretation much simpler
				 */
				/* Older servers doesn't know what jitter is, so if we get an
				 * error on the first pass we redo it with "dispersion" */
				strncpy(req.data, getvar, MAX_CM_SIZE - 1);
				req.count = htons(strlen(getvar));
				DBG(printf("sending READVAR request...\n"));
				write(conn, &req, SIZEOF_NTPCM(req));
				DBG(print_ntp_control_message(&req));

				do {
					req.count = htons(MAX_CM_SIZE);
					DBG(printf("receiving READVAR response...\n"));
					read(conn, &req, SIZEOF_NTPCM(req));
					DBG(print_ntp_control_message(&req));
				} while (!(req.op & OP_READVAR && ntohs(req.seq) == 2));

				if (!(req.op & REM_ERROR))
					xasprintf(&data, "%s%s", data, req.data);
			} while (req.op & REM_MORE);

			if (req.op & REM_ERROR) {
				if (strstr(getvar, "jitter")) {
					if (verbose)
						printf("The command failed. This is usually caused by servers refusing the 'jitter'\nvariable. Restarting with "
							   "'dispersion'...\n");
					getvar = "stratum,offset,dispersion";
					i--;
					continue;
				}
				if (strlen(getvar)) {
					if (verbose)
						printf("Server didn't like dispersion either; will retrieve everything\n");
					getvar = "";
					i--;
					continue;
				}
			}

			if (verbose > 1)
				printf("Server responded: >>>%s<<<\n", data);

			double tmp_offset = 0;
			char *value;
			char *nptr;
			/* get the offset */
			if (verbose)
				printf("parsing offset from peer %.2x: ", ntohs(peers[i].assoc));

			value = np_extract_ntpvar(data, "offset");
			nptr = NULL;
			/* Convert the value if we have one */
			if (value != NULL)
				tmp_offset = strtod(value, &nptr) / 1000;
			/* If value is null or no conversion was performed */
			if (value == NULL || value == nptr) {
				if (verbose)
					printf("error: unable to read server offset response.\n");
			} else {
				if (verbose)
					printf("%.10g\n", tmp_offset);
				if (*offset_result == STATE_UNKNOWN || fabs(tmp_offset) < fabs(*offset)) {
					*offset = tmp_offset;
					*offset_result = STATE_OK;
				} else {
					/* Skip this one; move to the next */
					continue;
				}
			}

			if (do_jitter) {
				/* get the jitter */
				if (verbose) {
					printf("parsing %s from peer %.2x: ", strstr(getvar, "dispersion") != NULL ? "dispersion" : "jitter",
						   ntohs(peers[i].assoc));
				}
				value = np_extract_ntpvar(data, strstr(getvar, "dispersion") != NULL ? "dispersion" : "jitter");
				nptr = NULL;
				/* Convert the value if we have one */
				if (value != NULL)
					*jitter = strtod(value, &nptr);
				/* If value is null or no conversion was performed */
				if (value == NULL || value == nptr) {
					if (verbose)
						printf("error: unable to read server jitter/dispersion response.\n");
					*jitter = -1;
				} else if (verbose) {
					printf("%.10g\n", *jitter);
				}
			}

			if (do_stratum) {
				/* get the stratum */
				if (verbose) {
					printf("parsing stratum from peer %.2x: ", ntohs(peers[i].assoc));
				}
				value = np_extract_ntpvar(data, "stratum");
				nptr = NULL;
				/* Convert the value if we have one */
				if (value != NULL)
					*stratum = strtol(value, &nptr, 10);
				if (value == NULL || value == nptr) {
					if (verbose)
						printf("error: unable to read server stratum response.\n");
					*stratum = -1;
				} else {
					if (verbose)
						printf("%i\n", *stratum);
				}
			}
		} /* if (PEER_SEL(peers[i].status) >= min_peer_sel) */
	}     /* for (i = 0; i < npeers; i++) */

	close(conn);
	if (peers != NULL)
		free(peers);

	return status;
}

int process_arguments(int argc, char **argv) {
	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'}, {"swarn", required_argument, 0, 'W'},
		{"scrit", required_argument, 0, 'C'},    {"jwarn", required_argument, 0, 'j'},    {"jcrit", required_argument, 0, 'k'},
		{"twarn", required_argument, 0, 'm'},    {"tcrit", required_argument, 0, 'n'},    {"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 (true) {
		int option = 0;
		int option_char = getopt_long(argc, argv, "Vhv46qw:c:W:C:j:k:m:n:t:H:p:", longopts, &option);
		if (option_char == -1 || option_char == EOF || option_char == 1)
			break;

		switch (option_char) {
		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 = true;
			break;
		case 'w':
			owarn = optarg;
			break;
		case 'c':
			ocrit = optarg;
			break;
		case 'W':
			do_stratum = true;
			swarn = optarg;
			break;
		case 'C':
			do_stratum = true;
			scrit = optarg;
			break;
		case 'j':
			do_jitter = true;
			jwarn = optarg;
			break;
		case 'k':
			do_jitter = true;
			jcrit = optarg;
			break;
		case 'm':
			do_truechimers = true;
			twarn = optarg;
			break;
		case 'n':
			do_truechimers = true;
			tcrit = optarg;
			break;
		case 'H':
			if (!is_host(optarg))
				usage2(_("Invalid hostname/address"), optarg);
			server_address = strdup(optarg);
			break;
		case 'p':
			port = atoi(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);
}

char *perfd_jitter(double jitter) {
	return fperfdata("jitter", jitter, "", do_jitter, jitter_thresholds->warning->end, do_jitter, jitter_thresholds->critical->end, true, 0,
					 false, 0);
}

char *perfd_stratum(int stratum) {
	return perfdata("stratum", stratum, "", do_stratum, (int)stratum_thresholds->warning->end, do_stratum,
					(int)stratum_thresholds->critical->end, true, 0, true, 16);
}

char *perfd_truechimers(int num_truechimers) {
	return perfdata("truechimers", num_truechimers, "", do_truechimers, (int)truechimer_thresholds->warning->end, do_truechimers,
					(int)truechimer_thresholds->critical->end, true, 0, false, 0);
}

int main(int argc, char *argv[]) {
	setlocale(LC_ALL, "");
	bindtextdomain(PACKAGE, LOCALEDIR);
	textdomain(PACKAGE);

	/* 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);
	set_thresholds(&jitter_thresholds, jwarn, jcrit);
	set_thresholds(&stratum_thresholds, swarn, scrit);
	set_thresholds(&truechimer_thresholds, twarn, tcrit);

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

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

	int offset_result;
	int stratum;
	int num_truechimers;
	double offset = 0;
	double jitter = 0;
	/* This returns either OK or WARNING (See comment preceding ntp_request) */
	int result = ntp_request(&offset, &offset_result, &jitter, &stratum, &num_truechimers);

	if (offset_result == STATE_UNKNOWN) {
		/* if there's no sync peer (this overrides ntp_request output): */
		result = (quiet ? STATE_UNKNOWN : STATE_CRITICAL);
	} else {
		/* Be quiet if there's no candidates either */
		if (quiet && result == STATE_WARNING)
			result = STATE_UNKNOWN;
		result = max_state_alt(result, get_status(fabs(offset), offset_thresholds));
	}

	int oresult = result;

	int tresult = STATE_UNKNOWN;

	if (do_truechimers) {
		tresult = get_status(num_truechimers, truechimer_thresholds);
		result = max_state_alt(result, tresult);
	}

	int sresult = STATE_UNKNOWN;

	if (do_stratum) {
		sresult = get_status(stratum, stratum_thresholds);
		result = max_state_alt(result, sresult);
	}

	int jresult = STATE_UNKNOWN;

	if (do_jitter) {
		jresult = get_status(jitter, jitter_thresholds);
		result = max_state_alt(result, jresult);
	}

	char *result_line;
	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 (!syncsource_found)
		xasprintf(&result_line, "%s %s,", result_line, _("Server not synchronized"));
	else if (li_alarm)
		xasprintf(&result_line, "%s %s,", result_line, _("Server has the LI_ALARM bit set"));

	char *perfdata_line;
	if (offset_result == STATE_UNKNOWN) {
		xasprintf(&result_line, "%s %s", result_line, _("Offset unknown"));
		xasprintf(&perfdata_line, "");
	} else if (oresult == STATE_WARNING) {
		xasprintf(&result_line, "%s %s %.10g secs (WARNING)", result_line, _("Offset"), offset);
	} else if (oresult == STATE_CRITICAL) {
		xasprintf(&result_line, "%s %s %.10g secs (CRITICAL)", result_line, _("Offset"), offset);
	} else {
		xasprintf(&result_line, "%s %s %.10g secs", result_line, _("Offset"), offset);
	}
	xasprintf(&perfdata_line, "%s", perfd_offset(offset));

	if (do_jitter) {
		if (jresult == STATE_WARNING) {
			xasprintf(&result_line, "%s, jitter=%f (WARNING)", result_line, jitter);
		} else if (jresult == STATE_CRITICAL) {
			xasprintf(&result_line, "%s, jitter=%f (CRITICAL)", result_line, jitter);
		} else {
			xasprintf(&result_line, "%s, jitter=%f", result_line, jitter);
		}
		xasprintf(&perfdata_line, "%s %s", perfdata_line, perfd_jitter(jitter));
	}
	if (do_stratum) {
		if (sresult == STATE_WARNING) {
			xasprintf(&result_line, "%s, stratum=%i (WARNING)", result_line, stratum);
		} else if (sresult == STATE_CRITICAL) {
			xasprintf(&result_line, "%s, stratum=%i (CRITICAL)", result_line, stratum);
		} else {
			xasprintf(&result_line, "%s, stratum=%i", result_line, stratum);
		}
		xasprintf(&perfdata_line, "%s %s", perfdata_line, perfd_stratum(stratum));
	}
	if (do_truechimers) {
		if (tresult == STATE_WARNING) {
			xasprintf(&result_line, "%s, truechimers=%i (WARNING)", result_line, num_truechimers);
		} else if (tresult == STATE_CRITICAL) {
			xasprintf(&result_line, "%s, truechimers=%i (CRITICAL)", result_line, num_truechimers);
		} else {
			xasprintf(&result_line, "%s, truechimers=%i", result_line, num_truechimers);
		}
		xasprintf(&perfdata_line, "%s %s", perfdata_line, perfd_truechimers(num_truechimers));
	}
	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 selected 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 or WARNING if server isn't synchronized"));
	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", "-W, --swarn=THRESHOLD");
	printf("    %s\n", _("Warning threshold for stratum of server's synchronization peer"));
	printf(" %s\n", "-C, --scrit=THRESHOLD");
	printf("    %s\n", _("Critical threshold for stratum of server's synchronization peer"));
	printf(" %s\n", "-j, --jwarn=THRESHOLD");
	printf("    %s\n", _("Warning threshold for jitter"));
	printf(" %s\n", "-k, --jcrit=THRESHOLD");
	printf("    %s\n", _("Critical threshold for jitter"));
	printf(" %s\n", "-m, --twarn=THRESHOLD");
	printf("    %s\n", _("Warning threshold for number of usable time sources (\"truechimers\")"));
	printf(" %s\n", "-n, --tcrit=THRESHOLD");
	printf("    %s\n", _("Critical threshold for number of usable time sources (\"truechimers\")"));
	printf(UT_CONN_TIMEOUT, DEFAULT_SOCKET_TIMEOUT);
	printf(UT_VERBOSE);

	printf("\n");
	printf("%s\n", _("This plugin checks an NTP server independent of any commandline"));
	printf("%s\n\n", _("programs or external libraries."));

	printf("%s\n", _("Notes:"));
	printf(" %s\n", _("Use this plugin to check the health of an NTP server. It supports"));
	printf(" %s\n", _("checking the offset with the sync peer, the jitter and stratum. This"));
	printf(" %s\n", _("plugin will not check the clock offset between the local host and NTP"));
	printf(" %s\n", _("server; please use check_ntp_time for that purpose."));
	printf("\n");
	printf(UT_THRESHOLDS_NOTES);

	printf("\n");
	printf("%s\n", _("Examples:"));
	printf(" %s\n", _("Simple NTP server check:"));
	printf("  %s\n", ("./check_ntp_peer -H ntpserv -w 0.5 -c 1"));
	printf("\n");
	printf(" %s\n", _("Check jitter too, avoiding critical notifications if jitter isn't available"));
	printf(" %s\n", _("(See Notes above for more details on thresholds formats):"));
	printf("  %s\n", ("./check_ntp_peer -H ntpserv -w 0.5 -c 1 -j -1:100 -k -1:200"));
	printf("\n");
	printf(" %s\n", _("Only check the number of usable time sources (\"truechimers\"):"));
	printf("  %s\n", ("./check_ntp_peer -H ntpserv -m @5 -n @3"));
	printf("\n");
	printf(" %s\n", _("Check only stratum:"));
	printf("  %s\n", ("./check_ntp_peer -H ntpserv -W 4 -C 6"));

	printf(UT_SUPPORT);
}

void print_usage(void) {
	printf("%s\n", _("Usage:"));
	printf(" %s -H <host> [-4|-6] [-w <warn>] [-c <crit>] [-W <warn>] [-C <crit>]\n", progname);
	printf("       [-j <warn>] [-k <crit>] [-v verbose]\n");
}
