initial version of the pure-c check_ntp implementation. jitter not yet

implemented, and a couple other misc things to do, so i haven't
yet patched Makefile.am


git-svn-id: https://nagiosplug.svn.sourceforge.net/svnroot/nagiosplug/nagiosplug/trunk@1330 f882894a-f735-0410-b71e-b25c423dba1c

plugins/check_ntp.c

@@ -0,0 +1,355 @@
+/******************************************************************************
+ check_ntp.c: utility to check ntp servers independant of any commandline
+              programs or external libraries.
+ original author: sean finney <seanius@seanius.net>
+ ******************************************************************************
+ 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 2 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, write to the Free Software
+ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+ $Id$
+ 
+*****************************************************************************/
+
+const char *progname = "check_ntp";
+const char *revision = "$Revision$";
+const char *copyright = "2006";
+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 zero_offset_bad=0;
+static double owarn=0;
+static double ocrit=0;
+static short do_jitter=0;
+static double jwarn=0;
+static double jcrit=0;
+
+int process_arguments (int, char **);
+void print_help (void);
+void print_usage (void);
+
+/* 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;
+
+/* 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)
+/* 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
+
+/**
+ ** 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((4294.967296*t.tv_usec)+.5); \
+		} \
+	} 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, rtdelay;
+	client_tx = NTP64asDOUBLE(m->origts);
+	peer_rx = NTP64asDOUBLE(m->rxts);
+	peer_tx = NTP64asDOUBLE(m->txts);
+	client_rx=TVasDOUBLE((*t));
+	rtdelay=NTP32asDOUBLE(m->rtdelay);
+	return (.5*((peer_tx-client_rx)+(peer_rx-client_tx)))-rtdelay;
+}
+
+/* print out a ntp packet in human readable/debuggable format */
+void print_packet(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=0xfa;
+	L16(p->rtdelay)=htons(1);
+	L16(p->rtdisp)=htons(1);
+
+	gettimeofday(&t, NULL);
+	TVtoNTP64(t,p->txts);
+}
+
+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'}, */
+		{"warning", required_argument, 0, 'w'},
+		{"critical", required_argument, 0, 'c'},
+		{"zero-offset", no_argument, 0, 'O'},
+		{"jwarn", required_argument, 0, 'j'},
+		{"jcrit", required_argument, 0, 'k'},
+		{"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, "Vhv4w:c:Oj:k: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 = 1;
+			break;
+		case 'w':
+			owarn = atof(optarg);
+			break;
+		case 'c':
+			ocrit = atof(optarg);
+			break;
+		case 'j':
+			do_jitter=1;
+			jwarn = atof(optarg);
+			break;
+		case 'k':
+			do_jitter=1;
+			jcrit = atof(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 'O':
+			zero_offset_bad=1;
+			break;
+		case '?':
+			/* print short usage statement if args not parsable */
+			usage2 (_("Unknown argument"), optarg);
+			break;
+		}
+	}
+
+	if (ocrit < owarn){
+		usage4(_("Critical offset should be larger than warning offset"));
+	}
+
+	if (ocrit < owarn){
+		usage4(_("Critical jitter should be larger than warning jitter"));
+	}
+
+	if(server_address == NULL){
+		usage4(_("Hostname was not supplied"));
+	}
+
+	return 0;
+}
+
+int main(int argc, char *argv[]){
+	int result = STATE_UNKNOWN;
+	int conn;
+	ntp_message m;
+	struct timeval recv_time;
+	double offset=0, jitter=0;
+
+	if (process_arguments (argc, argv) == ERROR)
+		usage4 (_("Could not parse arguments"));
+
+	/* initialize alarm signal handling */
+	signal (SIGALRM, socket_timeout_alarm_handler);
+
+	/* set socket timeout */
+	alarm (socket_timeout);
+
+	setup_request(&m);
+	if(verbose) print_packet(&m);
+	my_udp_connect(server_address, 123, &conn);
+	write(conn, &m, sizeof(ntp_message));
+	read(conn, &m, sizeof(ntp_message));
+	gettimeofday(&recv_time, NULL);
+	if(verbose) print_packet(&m);
+	close(conn);
+
+	offset=calc_offset(&m, &recv_time);
+	printf("total offset: %g\n", offset);
+
+	if(offset > ocrit){
+		printf("NTP CRITICAL: ");
+		result = STATE_CRITICAL;
+	} else if(offset > owarn) {
+		printf("NTP WARNING: ");
+		result = STATE_WARNING;
+	} else {
+		printf("NTP OK: ");
+		result = STATE_OK;
+	}
+
+	/* not implemented yet:
+	jitter=calc_jitter(&m, &recv_time);
+
+	if(do_jitter){
+		if(offset > ocrit){
+			printf("NTP CRITICAL: ");
+			result = STATE_CRITICAL;
+		} else if(offset > owarn) {
+			printf("NTP WARNING: ");
+			result = STATE_WARNING;
+		} else {
+			printf("NTP OK: ");
+			result = STATE_OK;
+		}
+	}
+	*/
+
+	printf("Offset %g secs|offset=%g\n", offset, offset);
+
+	if(server_address!=NULL) free(server_address);
+	return result;
+}
+
+
+void print_usage(void){
+	printf("\
+Usage: %s -H <host> [-O] [-w <warn>] [-c <crit>] [-j <warn>] [-k <crit>] [-v verbose]\
+\n", progname);
+}
+
+void print_help(void){
+	print_revision(progname, revision);
+
+	printf ("Copyright (c) 1999 Ethan Galstad\n");
+	printf (COPYRIGHT, copyright, email);
+
+	print_usage();
+	printf (_(UT_HELP_VRSN));
+	printf (_(UT_HOST_PORT), 'p', "123");
+	printf (_(UT_WARN_CRIT));
+	printf (_(UT_TIMEOUT), DEFAULT_SOCKET_TIMEOUT);
+	printf (_(UT_VERBOSE));
+	printf(_(UT_SUPPORT));
+}