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 #include "common.h"
25 #include "popen.h"
26 #include "utils.h"
27 #include "netutils.h"
29 const char *progname = "check_dns";
30 const char *revision = "$Revision$";
31 const char *copyright = "2000-2004";
32 const char *email = "nagiosplug-devel@lists.sourceforge.net";
34 int process_arguments (int, char **);
35 int validate_arguments (void);
36 int error_scan (char *);
37 void print_help (void);
38 void print_usage (void);
40 #define ADDRESS_LENGTH 256
41 char query_address[ADDRESS_LENGTH] = "";
42 char dns_server[ADDRESS_LENGTH] = "";
43 char ptr_server[ADDRESS_LENGTH] = "";
44 int verbose = FALSE;
45 char expected_address[ADDRESS_LENGTH] = "";
46 int match_expected_address = FALSE;
47 int expect_authority = FALSE;
49 int
50 main (int argc, char **argv)
51 {
52 char *command_line = NULL;
53 char input_buffer[MAX_INPUT_BUFFER];
54 char *output = NULL;
55 char *address = NULL;
56 char *temp_buffer = NULL;
57 int non_authoritative = FALSE;
58 int result = STATE_UNKNOWN;
59 double elapsed_time;
60 long microsec;
61 struct timeval tv;
62 int multi_address;
63 int parse_address = FALSE; /* This flag scans for Address: but only after Name: */
65 setlocale (LC_ALL, "");
66 bindtextdomain (PACKAGE, LOCALEDIR);
67 textdomain (PACKAGE);
69 /* Set signal handling and alarm */
70 if (signal (SIGALRM, popen_timeout_alarm_handler) == SIG_ERR) {
71 printf (_("Cannot catch SIGALRM"));
72 return STATE_UNKNOWN;
73 }
75 if (process_arguments (argc, argv) != OK) {
76 usage (_("check_dns: could not parse arguments\n"));
77 return STATE_UNKNOWN;
78 }
80 /* get the command to run */
81 asprintf (&command_line, "%s %s %s", NSLOOKUP_COMMAND, query_address, dns_server);
83 alarm (timeout_interval);
84 gettimeofday (&tv, NULL);
86 if (verbose)
87 printf ("%s\n", command_line);
89 /* run the command */
90 child_process = spopen (command_line);
91 if (child_process == NULL) {
92 printf (_("Could not open pipe: %s\n"), command_line);
93 return STATE_UNKNOWN;
94 }
96 child_stderr = fdopen (child_stderr_array[fileno (child_process)], "r");
97 if (child_stderr == NULL)
98 printf (_("Could not open stderr for %s\n"), command_line);
100 /* scan stdout */
101 while (fgets (input_buffer, MAX_INPUT_BUFFER - 1, child_process)) {
103 if (verbose)
104 printf ("%s", input_buffer);
106 if (strstr (input_buffer, ".in-addr.arpa")) {
107 if ((temp_buffer = strstr (input_buffer, "name = ")))
108 address = strdup (temp_buffer + 7);
109 else {
110 output = strdup (_("Unknown error (plugin)"));
111 result = STATE_WARNING;
112 }
113 }
115 /* the server is responding, we just got the host name... */
116 if (strstr (input_buffer, "Name:"))
117 parse_address = TRUE;
118 else if (parse_address == TRUE && (strstr (input_buffer, "Address:") ||
119 strstr (input_buffer, "Addresses:"))) {
120 temp_buffer = index (input_buffer, ':');
121 temp_buffer++;
123 /* Strip leading spaces */
124 for (; *temp_buffer != '\0' && *temp_buffer == ' '; temp_buffer++)
125 /* NOOP */;
127 strip(temp_buffer);
128 if (temp_buffer==NULL || strlen(temp_buffer)==0) {
129 die (STATE_CRITICAL,
130 _("DNS CRITICAL - '%s' returned empty host name string\n"),
131 NSLOOKUP_COMMAND);
132 }
134 if (address == NULL)
135 address = strdup (temp_buffer);
136 else
137 asprintf(&address, "%s,%s", address, temp_buffer);
138 }
140 else if (strstr (input_buffer, "Non-authoritative answer:")) {
141 non_authoritative = TRUE;
142 }
144 result = error_scan (input_buffer);
145 if (result != STATE_OK) {
146 output = strdup (1 + index (input_buffer, ':'));
147 strip (output);
148 break;
149 }
151 }
153 /* scan stderr */
154 while (fgets (input_buffer, MAX_INPUT_BUFFER - 1, child_stderr)) {
155 if (error_scan (input_buffer) != STATE_OK) {
156 result = max_state (result, error_scan (input_buffer));
157 output = strdup (1 + index (input_buffer, ':'));
158 strip (output);
159 }
160 }
162 /* close stderr */
163 (void) fclose (child_stderr);
165 /* close stdout */
166 if (spclose (child_process)) {
167 result = max_state (result, STATE_WARNING);
168 if (!strcmp (output, ""))
169 output = strdup (_("nslookup returned error status"));
170 }
172 /* If we got here, we should have an address string,
173 and we can segfault if we do not */
174 if (address==NULL || strlen(address)==0)
175 die (STATE_CRITICAL,
176 _("DNS CRITICAL - '%s' output parsing exited with no address\n"),
177 NSLOOKUP_COMMAND);
179 /* compare to expected address */
180 if (result == STATE_OK && match_expected_address && strcmp(address, expected_address)) {
181 result = STATE_CRITICAL;
182 asprintf(&output, _("expected %s but got %s"), expected_address, address);
183 }
185 /* check if authoritative */
186 if (result == STATE_OK && expect_authority && non_authoritative) {
187 result = STATE_CRITICAL;
188 asprintf(&output, _("server %s is not authoritative for %s"), dns_server, query_address);
189 }
191 microsec = deltime (tv);
192 elapsed_time = (double)microsec / 1.0e6;
194 if (result == STATE_OK) {
195 if (strchr (address, ',') == NULL)
196 multi_address = FALSE;
197 else
198 multi_address = TRUE;
200 printf ("DNS %s: ", _("OK"));
201 printf (ngettext("%.3f second response time, ", "%.3f seconds response time, ", elapsed_time), elapsed_time);
202 printf (_("%s returns %s"), query_address, address);
203 printf ("|%s\n", fperfdata ("time", elapsed_time, "s", FALSE, 0, FALSE, 0, TRUE, 0, FALSE, 0));
204 }
205 else if (result == STATE_WARNING)
206 printf (_("DNS WARNING - %s\n"),
207 !strcmp (output, "") ? _(" Probably a non-existent host/domain") : output);
208 else if (result == STATE_CRITICAL)
209 printf (_("DNS CRITICAL - %s\n"),
210 !strcmp (output, "") ? _(" Probably a non-existent host/domain") : output);
211 else
212 printf (_("DNS UNKNOW - %s\n"),
213 !strcmp (output, "") ? _(" Probably a non-existent host/domain") : output);
215 return result;
216 }
220 int
221 error_scan (char *input_buffer)
222 {
224 /* the DNS lookup timed out */
225 if (strstr (input_buffer, "Note: nslookup is deprecated and may be removed from future releases.") ||
226 strstr (input_buffer, "Consider using the `dig' or `host' programs instead. Run nslookup with") ||
227 strstr (input_buffer, "the `-sil[ent]' option to prevent this message from appearing."))
228 return STATE_OK;
230 /* DNS server is not running... */
231 else if (strstr (input_buffer, "No response from server"))
232 die (STATE_CRITICAL, _("No response from DNS %s\n"), dns_server);
234 /* Host name is valid, but server doesn't have records... */
235 else if (strstr (input_buffer, "No records"))
236 die (STATE_CRITICAL, _("DNS %s has no records\n"), dns_server);
238 /* Connection was refused */
239 else if (strstr (input_buffer, "Connection refused") ||
240 strstr (input_buffer, "Refused") ||
241 (strstr (input_buffer, "** server can't find") &&
242 strstr (input_buffer, ": REFUSED")))
243 die (STATE_CRITICAL, _("Connection to DNS %s was refused\n"), dns_server);
245 /* Host or domain name does not exist */
246 else if (strstr (input_buffer, "Non-existent") ||
247 strstr (input_buffer, "** server can't find") ||
248 strstr (input_buffer,"NXDOMAIN"))
249 die (STATE_CRITICAL, _("Domain %s was not found by the server\n"), query_address);
251 /* Network is unreachable */
252 else if (strstr (input_buffer, "Network is unreachable"))
253 die (STATE_CRITICAL, _("Network is unreachable\n"));
255 /* Internal server failure */
256 else if (strstr (input_buffer, "Server failure"))
257 die (STATE_CRITICAL, _("DNS failure for %s\n"), dns_server);
259 /* Request error or the DNS lookup timed out */
260 else if (strstr (input_buffer, "Format error") ||
261 strstr (input_buffer, "Timed out"))
262 return STATE_WARNING;
264 return STATE_OK;
266 }
270 /* process command-line arguments */
271 int
272 process_arguments (int argc, char **argv)
273 {
274 int c;
276 int opt_index = 0;
277 static struct option long_opts[] = {
278 {"help", no_argument, 0, 'h'},
279 {"version", no_argument, 0, 'V'},
280 {"verbose", no_argument, 0, 'v'},
281 {"timeout", required_argument, 0, 't'},
282 {"hostname", required_argument, 0, 'H'},
283 {"server", required_argument, 0, 's'},
284 {"reverse-server", required_argument, 0, 'r'},
285 {"expected-address", required_argument, 0, 'a'},
286 {"expect-authority", no_argument, 0, 'A'},
287 {0, 0, 0, 0}
288 };
290 if (argc < 2)
291 return ERROR;
293 for (c = 1; c < argc; c++)
294 if (strcmp ("-to", argv[c]) == 0)
295 strcpy (argv[c], "-t");
297 while (1) {
298 c = getopt_long (argc, argv, "hVvAt:H:s:r:a:", long_opts, &opt_index);
300 if (c == -1 || c == EOF)
301 break;
303 switch (c) {
304 case '?': /* args not parsable */
305 printf (_("%s: Unknown argument: %s\n\n"), progname, optarg);
306 print_usage ();
307 exit (STATE_UNKNOWN);
308 case 'h': /* help */
309 print_help ();
310 exit (STATE_OK);
311 case 'V': /* version */
312 print_revision (progname, revision);
313 exit (STATE_OK);
314 case 'v': /* version */
315 verbose = TRUE;
316 break;
317 case 't': /* timeout period */
318 timeout_interval = atoi (optarg);
319 break;
320 case 'H': /* hostname */
321 if (strlen (optarg) >= ADDRESS_LENGTH)
322 die (STATE_UNKNOWN, _("Input buffer overflow\n"));
323 strcpy (query_address, optarg);
324 break;
325 case 's': /* server name */
326 /* TODO: this is_host check is probably unnecessary. */
327 /* Better to confirm nslookup response matches */
328 if (is_host (optarg) == FALSE) {
329 printf (_("Invalid hostname/address\n\n"));
330 print_usage ();
331 exit (STATE_UNKNOWN);
332 }
333 if (strlen (optarg) >= ADDRESS_LENGTH)
334 die (STATE_UNKNOWN, _("Input buffer overflow\n"));
335 strcpy (dns_server, optarg);
336 break;
337 case 'r': /* reverse server name */
338 /* TODO: Is this is_host necessary? */
339 if (is_host (optarg) == FALSE) {
340 usage2 (_("Invalid hostname/address"), optarg);
341 }
342 if (strlen (optarg) >= ADDRESS_LENGTH)
343 die (STATE_UNKNOWN, _("Input buffer overflow\n"));
344 strcpy (ptr_server, optarg);
345 break;
346 case 'a': /* expected address */
347 if (strlen (optarg) >= ADDRESS_LENGTH)
348 die (STATE_UNKNOWN, _("Input buffer overflow\n"));
349 strcpy (expected_address, optarg);
350 match_expected_address = TRUE;
351 break;
352 case 'A': /* expect authority */
353 expect_authority = TRUE;
354 break;
355 }
356 }
358 c = optind;
359 if (strlen(query_address)==0 && c<argc) {
360 if (strlen(argv[c])>=ADDRESS_LENGTH)
361 die (STATE_UNKNOWN, _("Input buffer overflow\n"));
362 strcpy (query_address, argv[c++]);
363 }
365 if (strlen(dns_server)==0 && c<argc) {
366 /* TODO: See -s option */
367 if (is_host(argv[c]) == FALSE) {
368 printf (_("Invalid hostname/address: %s\n\n"), argv[c]);
369 return ERROR;
370 }
371 if (strlen(argv[c]) >= ADDRESS_LENGTH)
372 die (STATE_UNKNOWN, _("Input buffer overflow\n"));
373 strcpy (dns_server, argv[c++]);
374 }
376 return validate_arguments ();
377 }
381 int
382 validate_arguments ()
383 {
384 if (query_address[0] == 0)
385 return ERROR;
386 else
387 return OK;
388 }
392 void
393 print_help (void)
394 {
395 print_revision (progname, revision);
397 printf ("Copyright (c) 1999 Ethan Galstad <nagios@nagios.org>\n");
398 printf (COPYRIGHT, copyright, email);
400 print_usage ();
402 printf (_(UT_HELP_VRSN));
404 printf (_("\
405 -H, --hostname=HOST\n\
406 The name or address you want to query\n\
407 -s, --server=HOST\n\
408 Optional DNS server you want to use for the lookup\n\
409 -a, --expected-address=IP-ADDRESS\n\
410 Optional IP address you expect the DNS server to return\n\
411 -A, --expect-authority\n\
412 Optionally expect the DNS server to be authoritative for the lookup\n"));
414 printf (_(UT_TIMEOUT), DEFAULT_SOCKET_TIMEOUT);
416 printf (_("\n\
417 This plugin uses the nslookup program to obtain the IP address\n\
418 for the given host/domain query. A optional DNS server to use may\n\
419 be specified. If no DNS server is specified, the default server(s)\n\
420 specified in /etc/resolv.conf will be used.\n"));
422 printf (_(UT_SUPPORT));
423 }
427 void
428 print_usage (void)
429 {
430 printf (_("\
431 Usage: %s -H host [-s server] [-a expected-address] [-A] [-t timeout]\n\
432 %s --help\n\
433 %s --version\n"), progname, progname, progname);
434 }