1 /******************************************************************************
3 This program is free software; you can redistribute it and/or modify
4 it under the terms of the GNU General Public License as published by
5 the Free Software Foundation; either version 2 of the License, or
6 (at your option) any later version.
8 This program is distributed in the hope that it will be useful,
9 but WITHOUT ANY WARRANTY; without even the implied warranty of
10 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 GNU General Public License for more details.
13 You should have received a copy of the GNU General Public License
14 along with this program; if not, write to the Free Software
15 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 LIMITATION: nslookup on Solaris 7 can return output over 2 lines, which will not
18 be picked up by this plugin
20 $Id$
22 ******************************************************************************/
24 const char *progname = "check_dns";
25 const char *revision = "$Revision$";
26 const char *copyright = "2000-2005";
27 const char *email = "nagiosplug-devel@lists.sourceforge.net";
29 #include "common.h"
30 #include "utils.h"
31 #include "utils_base.h"
32 #include "netutils.h"
33 #include "runcmd.h"
35 int process_arguments (int, char **);
36 int validate_arguments (void);
37 int error_scan (char *);
38 void print_help (void);
39 void print_usage (void);
41 #define ADDRESS_LENGTH 256
42 char query_address[ADDRESS_LENGTH] = "";
43 char dns_server[ADDRESS_LENGTH] = "";
44 char ptr_server[ADDRESS_LENGTH] = "";
45 int verbose = FALSE;
46 char expected_address[ADDRESS_LENGTH] = "";
47 int match_expected_address = FALSE;
48 int expect_authority = FALSE;
49 thresholds *time_thresholds = NULL;
51 int
52 main (int argc, char **argv)
53 {
54 char *command_line = NULL;
55 char input_buffer[MAX_INPUT_BUFFER];
56 char *address = NULL;
57 char *msg = NULL;
58 char *temp_buffer = NULL;
59 int non_authoritative = FALSE;
60 int result = STATE_UNKNOWN;
61 double elapsed_time;
62 long microsec;
63 struct timeval tv;
64 int multi_address;
65 int parse_address = FALSE; /* This flag scans for Address: but only after Name: */
66 output chld_out, chld_err;
67 size_t i;
69 setlocale (LC_ALL, "");
70 bindtextdomain (PACKAGE, LOCALEDIR);
71 textdomain (PACKAGE);
73 /* Set signal handling and alarm */
74 if (signal (SIGALRM, popen_timeout_alarm_handler) == SIG_ERR) {
75 usage_va(_("Cannot catch SIGALRM"));
76 }
78 if (process_arguments (argc, argv) == ERROR) {
79 usage_va(_("Could not parse arguments"));
80 }
82 /* get the command to run */
83 asprintf (&command_line, "%s %s %s", NSLOOKUP_COMMAND, query_address, dns_server);
85 alarm (timeout_interval);
86 gettimeofday (&tv, NULL);
88 if (verbose)
89 printf ("%s\n", command_line);
91 /* run the command */
92 if((np_runcmd(command_line, &chld_out, &chld_err, 0)) != 0) {
93 msg = (char *)_("nslookup returned an error status");
94 result = STATE_WARNING;
95 }
97 /* scan stdout */
98 for(i = 0; i < chld_out.lines; i++) {
99 if (verbose)
100 puts(chld_out.line[i]);
102 if (strstr (chld_out.line[i], ".in-addr.arpa")) {
103 if ((temp_buffer = strstr (chld_out.line[i], "name = ")))
104 address = strdup (temp_buffer + 7);
105 else {
106 msg = (char *)_("Warning plugin error");
107 result = STATE_WARNING;
108 }
109 }
111 /* the server is responding, we just got the host name... */
112 if (strstr (chld_out.line[i], "Name:"))
113 parse_address = TRUE;
114 else if (parse_address == TRUE && (strstr (chld_out.line[i], "Address:") ||
115 strstr (chld_out.line[i], "Addresses:"))) {
116 temp_buffer = index (chld_out.line[i], ':');
117 temp_buffer++;
119 /* Strip leading spaces */
120 for (; *temp_buffer != '\0' && *temp_buffer == ' '; temp_buffer++)
121 /* NOOP */;
123 strip(temp_buffer);
124 if (temp_buffer==NULL || strlen(temp_buffer)==0) {
125 die (STATE_CRITICAL,
126 _("DNS CRITICAL - '%s' returned empty host name string\n"),
127 NSLOOKUP_COMMAND);
128 }
130 if (address == NULL)
131 address = strdup (temp_buffer);
132 else
133 asprintf(&address, "%s,%s", address, temp_buffer);
134 }
136 else if (strstr (chld_out.line[i], _("Non-authoritative answer:"))) {
137 non_authoritative = TRUE;
138 }
140 result = error_scan (chld_out.line[i]);
141 if (result != STATE_OK) {
142 msg = strchr (chld_out.line[i], ':');
143 if(msg) msg++;
144 break;
145 }
146 }
148 /* scan stderr */
149 for(i = 0; i < chld_err.lines; i++) {
150 if (verbose)
151 puts(chld_err.line[i]);
153 if (error_scan (chld_err.line[i]) != STATE_OK) {
154 result = max_state (result, error_scan (chld_err.line[i]));
155 msg = strchr(input_buffer, ':');
156 if(msg) msg++;
157 }
158 }
160 /* If we got here, we should have an address string,
161 * and we can segfault if we do not */
162 if (address==NULL || strlen(address)==0)
163 die (STATE_CRITICAL,
164 _("DNS CRITICAL - '%s' msg parsing exited with no address\n"),
165 NSLOOKUP_COMMAND);
167 /* compare to expected address */
168 if (result == STATE_OK && match_expected_address && strcmp(address, expected_address)) {
169 result = STATE_CRITICAL;
170 asprintf(&msg, _("expected '%s' but got '%s'"), expected_address, address);
171 }
173 /* check if authoritative */
174 if (result == STATE_OK && expect_authority && non_authoritative) {
175 result = STATE_CRITICAL;
176 asprintf(&msg, _("server %s is not authoritative for %s"), dns_server, query_address);
177 }
179 microsec = deltime (tv);
180 elapsed_time = (double)microsec / 1.0e6;
182 if (result == STATE_OK) {
183 if (strchr (address, ',') == NULL)
184 multi_address = FALSE;
185 else
186 multi_address = TRUE;
188 result = get_status(elapsed_time, time_thresholds);
189 if (result == STATE_OK) {
190 printf ("DNS %s: ", _("OK"));
191 } else if (result == STATE_WARNING) {
192 printf ("DNS %s: ", _("WARNING"));
193 } else if (result == STATE_CRITICAL) {
194 printf ("DNS %s: ", _("CRITICAL"));
195 }
196 printf (ngettext("%.3f second response time", "%.3f seconds response time", elapsed_time), elapsed_time);
197 printf (_(". %s returns %s"), query_address, address);
198 printf ("|%s\n", fperfdata ("time", elapsed_time, "s", FALSE, 0, FALSE, 0, TRUE, 0, FALSE, 0));
199 }
200 else if (result == STATE_WARNING)
201 printf (_("DNS WARNING - %s\n"),
202 !strcmp (msg, "") ? _(" Probably a non-existent host/domain") : msg);
203 else if (result == STATE_CRITICAL)
204 printf (_("DNS CRITICAL - %s\n"),
205 !strcmp (msg, "") ? _(" Probably a non-existent host/domain") : msg);
206 else
207 printf (_("DNS UNKNOW - %s\n"),
208 !strcmp (msg, "") ? _(" Probably a non-existent host/domain") : msg);
210 return result;
211 }
215 int
216 error_scan (char *input_buffer)
217 {
219 /* the DNS lookup timed out */
220 if (strstr (input_buffer, _("Note: nslookup is deprecated and may be removed from future releases.")) ||
221 strstr (input_buffer, _("Consider using the `dig' or `host' programs instead. Run nslookup with")) ||
222 strstr (input_buffer, _("the `-sil[ent]' option to prevent this message from appearing.")))
223 return STATE_OK;
225 /* DNS server is not running... */
226 else if (strstr (input_buffer, "No response from server"))
227 die (STATE_CRITICAL, _("No response from DNS %s\n"), dns_server);
229 /* Host name is valid, but server doesn't have records... */
230 else if (strstr (input_buffer, "No records"))
231 die (STATE_CRITICAL, _("DNS %s has no records\n"), dns_server);
233 /* Connection was refused */
234 else if (strstr (input_buffer, "Connection refused") ||
235 strstr (input_buffer, "Couldn't find server") ||
236 strstr (input_buffer, "Refused") ||
237 (strstr (input_buffer, "** server can't find") &&
238 strstr (input_buffer, ": REFUSED")))
239 die (STATE_CRITICAL, _("Connection to DNS %s was refused\n"), dns_server);
241 /* Query refused (usually by an ACL in the namserver) */
242 else if (strstr (input_buffer, "Query refused"))
243 die (STATE_CRITICAL, _("Query was refused by DNS server at %s\n"), dns_server);
245 /* No information (e.g. nameserver IP has two PTR records) */
246 else if (strstr (input_buffer, "No information"))
247 die (STATE_CRITICAL, _("No information returned by DNS server at %s\n"), dns_server);
249 /* Host or domain name does not exist */
250 else if (strstr (input_buffer, "Non-existent") ||
251 strstr (input_buffer, "** server can't find") ||
252 strstr (input_buffer,"NXDOMAIN"))
253 die (STATE_CRITICAL, _("Domain %s was not found by the server\n"), query_address);
255 /* Network is unreachable */
256 else if (strstr (input_buffer, "Network is unreachable"))
257 die (STATE_CRITICAL, _("Network is unreachable\n"));
259 /* Internal server failure */
260 else if (strstr (input_buffer, "Server failure"))
261 die (STATE_CRITICAL, _("DNS failure for %s\n"), dns_server);
263 /* Request error or the DNS lookup timed out */
264 else if (strstr (input_buffer, "Format error") ||
265 strstr (input_buffer, "Timed out"))
266 return STATE_WARNING;
268 return STATE_OK;
270 }
273 /* process command-line arguments */
274 int
275 process_arguments (int argc, char **argv)
276 {
277 int c;
278 char *warning = NULL;
279 char *critical = NULL;
281 int opt_index = 0;
282 static struct option long_opts[] = {
283 {"help", no_argument, 0, 'h'},
284 {"version", no_argument, 0, 'V'},
285 {"verbose", no_argument, 0, 'v'},
286 {"timeout", required_argument, 0, 't'},
287 {"hostname", required_argument, 0, 'H'},
288 {"server", required_argument, 0, 's'},
289 {"reverse-server", required_argument, 0, 'r'},
290 {"expected-address", required_argument, 0, 'a'},
291 {"expect-authority", no_argument, 0, 'A'},
292 {"warning", no_argument, 0, 'w'},
293 {"critical", no_argument, 0, 'c'},
294 {0, 0, 0, 0}
295 };
297 if (argc < 2)
298 return ERROR;
300 for (c = 1; c < argc; c++)
301 if (strcmp ("-to", argv[c]) == 0)
302 strcpy (argv[c], "-t");
304 while (1) {
305 c = getopt_long (argc, argv, "hVvAt:H:s:r:a:w:c:", long_opts, &opt_index);
307 if (c == -1 || c == EOF)
308 break;
310 switch (c) {
311 case 'h': /* help */
312 print_help ();
313 exit (STATE_OK);
314 case 'V': /* version */
315 print_revision (progname, revision);
316 exit (STATE_OK);
317 case 'v': /* version */
318 verbose = TRUE;
319 break;
320 case 't': /* timeout period */
321 timeout_interval = atoi (optarg);
322 break;
323 case 'H': /* hostname */
324 if (strlen (optarg) >= ADDRESS_LENGTH)
325 die (STATE_UNKNOWN, _("Input buffer overflow\n"));
326 strcpy (query_address, optarg);
327 break;
328 case 's': /* server name */
329 /* TODO: this host_or_die check is probably unnecessary.
330 * Better to confirm nslookup response matches */
331 host_or_die(optarg);
332 if (strlen (optarg) >= ADDRESS_LENGTH)
333 die (STATE_UNKNOWN, _("Input buffer overflow\n"));
334 strcpy (dns_server, optarg);
335 break;
336 case 'r': /* reverse server name */
337 /* TODO: Is this host_or_die necessary? */
338 host_or_die(optarg);
339 if (strlen (optarg) >= ADDRESS_LENGTH)
340 die (STATE_UNKNOWN, _("Input buffer overflow\n"));
341 strcpy (ptr_server, optarg);
342 break;
343 case 'a': /* expected address */
344 if (strlen (optarg) >= ADDRESS_LENGTH)
345 die (STATE_UNKNOWN, _("Input buffer overflow\n"));
346 strcpy (expected_address, optarg);
347 match_expected_address = TRUE;
348 break;
349 case 'A': /* expect authority */
350 expect_authority = TRUE;
351 break;
352 case 'w':
353 warning = optarg;
354 break;
355 case 'c':
356 critical = optarg;
357 break;
358 default: /* args not parsable */
359 usage_va(_("Unknown argument - %s"), optarg);
360 }
361 }
363 c = optind;
364 if (strlen(query_address)==0 && c<argc) {
365 if (strlen(argv[c])>=ADDRESS_LENGTH)
366 die (STATE_UNKNOWN, _("Input buffer overflow\n"));
367 strcpy (query_address, argv[c++]);
368 }
370 if (strlen(dns_server)==0 && c<argc) {
371 /* TODO: See -s option */
372 host_or_die(argv[c]);
373 if (strlen(argv[c]) >= ADDRESS_LENGTH)
374 die (STATE_UNKNOWN, _("Input buffer overflow\n"));
375 strcpy (dns_server, argv[c++]);
376 }
378 set_thresholds(&time_thresholds, warning, critical);
380 return validate_arguments ();
381 }
384 int
385 validate_arguments ()
386 {
387 if (query_address[0] == 0)
388 return ERROR;
390 return OK;
391 }
394 void
395 print_help (void)
396 {
397 print_revision (progname, revision);
399 printf ("Copyright (c) 1999 Ethan Galstad <nagios@nagios.org>\n");
400 printf (COPYRIGHT, copyright, email);
402 printf ("%s\n", _("This plugin uses the nslookup program to obtain the IP address for the given host/domain query."));
403 printf ("%s\n", _("An optional DNS server to use may be specified."));
404 printf ("%s\n", _("If no DNS server is specified, the default server(s) specified in /etc/resolv.conf will be used."));
406 printf ("\n\n");
408 print_usage ();
410 printf (_(UT_HELP_VRSN));
412 printf (" -H, --hostname=HOST\n");
413 printf (" %s\n", _("The name or address you want to query"));
414 printf (" -s, --server=HOST\n");
415 printf (" %s\n", _("Optional DNS server you want to use for the lookup"));
416 printf (" -a, --expected-address=IP-ADDRESS|HOST\n");
417 printf (" %s\n", _("Optional IP-ADDRESS you expect the DNS server to return. HOST must end with ."));
418 printf (" -A, --expect-authority\n");
419 printf (" %s\n", _("Optionally expect the DNS server to be authoritative for the lookup"));
420 printf (" -w, --warning=seconds\n");
421 printf (" %s\n", _("Return warning if elapsed time exceeds value. Default off"));
422 printf (" -c, --critical=seconds\n");
423 printf (" %s\n", _("Return critical if elapsed time exceeds value. Default off"));
425 printf (_(UT_TIMEOUT), DEFAULT_SOCKET_TIMEOUT);
426 printf (_(UT_SUPPORT));
427 }
430 void
431 print_usage (void)
432 {
433 printf (_("Usage:"));
434 printf ("%s -H host [-s server] [-a expected-address] [-A] [-t timeout] [-w warn] [-c crit]\n", progname);
435 }