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Diffstat (limited to 'plugins/check_dns.c')
| -rw-r--r-- | plugins/check_dns.c | 415 |
1 files changed, 415 insertions, 0 deletions
diff --git a/plugins/check_dns.c b/plugins/check_dns.c new file mode 100644 index 00000000..eaff4372 --- /dev/null +++ b/plugins/check_dns.c @@ -0,0 +1,415 @@ +/****************************************************************************** + * + * CHECK_DNS.C + * + * Program: DNS plugin for Nagios + * License: GPL + * Copyright (c) 1999 Ethan Galstad (nagios@nagios.org) + * + * Last Modified: $Date$ + * + * Notes: + * - Safe popen added by Karl DeBisschop 9-11-99 + * + * Command line: CHECK_DNS <query_address> [dns_server] + * + * Description: + * + * This program will use the nslookup program to obtain the IP address + * for a given host name. A optional DNS server may be specified. If + * no DNS server is specified, the default server(s) for the system + * are used. + * + * Return Values: + * OK The DNS query was successful (host IP address was returned). + * WARNING The DNS server responded, but could not fulfill the request. + * CRITICAL The DNS server is not responding or encountered an error. + * + * License Information: + * + * 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. + * + *****************************************************************************/ + +#include "common.h" +#include "popen.h" +#include "utils.h" + +int process_arguments (int, char **); +int call_getopt (int, char **); +int validate_arguments (void); +void print_usage (char *); +void print_help (char *); +int error_scan (char *); + +#define ADDRESS_LENGTH 256 +char query_address[ADDRESS_LENGTH] = ""; +char dns_server[ADDRESS_LENGTH] = ""; +char ptr_server[ADDRESS_LENGTH] = ""; +int verbose = FALSE; + +int +main (int argc, char **argv) +{ + char *command_line = NULL; + char input_buffer[MAX_INPUT_BUFFER]; + char *output = NULL; + char *address = NULL; + char *temp_buffer = NULL; + int result = STATE_UNKNOWN; + + /* Set signal handling and alarm */ + if (signal (SIGALRM, popen_timeout_alarm_handler) == SIG_ERR) { + printf ("Cannot catch SIGALRM"); + return STATE_UNKNOWN; + } + + if (process_arguments (argc, argv) != OK) { + print_usage (my_basename (argv[0])); + return STATE_UNKNOWN; + } + + /* get the command to run */ + command_line = ssprintf (command_line, "%s %s %s", NSLOOKUP_COMMAND, + query_address, dns_server); + + alarm (timeout_interval); + time (&start_time); + + if (verbose) + printf ("%s\n", command_line); + /* run the command */ + child_process = spopen (command_line); + if (child_process == NULL) { + printf ("Could not open pipe: %s\n", command_line); + return STATE_UNKNOWN; + } + + child_stderr = fdopen (child_stderr_array[fileno (child_process)], "r"); + if (child_stderr == NULL) + printf ("Could not open stderr for %s\n", command_line); + + /* scan stdout */ + while (fgets (input_buffer, MAX_INPUT_BUFFER - 1, child_process)) { + + if (verbose) + printf ("%s\n", input_buffer); + + if (strstr (input_buffer, ".in-addr.arpa")) { + if ((temp_buffer = strstr (input_buffer, "name = "))) + address = strscpy (address, temp_buffer + 7); + else { + output = strscpy (output, "Unknown error (plugin)"); + result = STATE_WARNING; + } + } + + /* the server is responding, we just got the host name... */ + if (strstr (input_buffer, "Name:")) { + + /* get the host address */ + if (!fgets (input_buffer, MAX_INPUT_BUFFER - 1, child_process)) + break; + + if (verbose) + printf ("%s\n", input_buffer); + + if ((temp_buffer = index (input_buffer, ':'))) { + address = strscpy (address, temp_buffer + 2); + strip (address); + result = STATE_OK; + } + else { + output = strscpy (output, "Unknown error (plugin)"); + result = STATE_WARNING; + } + + break; + } + + result = error_scan (input_buffer); + if (result != STATE_OK) { + output = strscpy (output, 1 + index (input_buffer, ':')); + break; + } + + } + + /* scan stderr */ + while (fgets (input_buffer, MAX_INPUT_BUFFER - 1, child_stderr)) { + if (error_scan (input_buffer) != STATE_OK) { + result = max (result, error_scan (input_buffer)); + output = strscpy (output, 1 + index (input_buffer, ':')); + } + } + + /* close stderr */ + (void) fclose (child_stderr); + + /* close stdout */ + if (spclose (child_process)) { + result = max (result, STATE_WARNING); + if (!strcmp (output, "")) + output = strscpy (output, "nslookup returned error status"); + } + + (void) time (&end_time); + + if (result == STATE_OK) + printf ("DNS ok - %d seconds response time, Address(es) is/are %s\n", + (int) (end_time - start_time), address); + else if (result == STATE_WARNING) + printf ("DNS WARNING - %s\n", + !strcmp (output, "") ? " Probably a non-existent host/domain" : output); + else if (result == STATE_CRITICAL) + printf ("DNS CRITICAL - %s\n", + !strcmp (output, "") ? " Probably a non-existent host/domain" : output); + else + printf ("DNS problem - %s\n", + !strcmp (output, "") ? " Probably a non-existent host/domain" : output); + + return result; +} + +int +error_scan (char *input_buffer) +{ + + /* the DNS lookup timed out */ + if (strstr (input_buffer, + "Note: nslookup is deprecated and may be removed from future releases.") + || strstr (input_buffer, + "Consider using the `dig' or `host' programs instead. Run nslookup with") + || strstr (input_buffer, + "the `-sil[ent]' option to prevent this message from appearing.")) + return STATE_OK; + + /* the DNS lookup timed out */ + else if (strstr (input_buffer, "Timed out")) + return STATE_WARNING; + + /* DNS server is not running... */ + else if (strstr (input_buffer, "No response from server")) + return STATE_CRITICAL; + + /* Host name is valid, but server doesn't have records... */ + else if (strstr (input_buffer, "No records")) + return STATE_WARNING; + + /* Host or domain name does not exist */ + else if (strstr (input_buffer, "Non-existent")) + return STATE_CRITICAL; + else if (strstr (input_buffer, "** server can't find")) + return STATE_CRITICAL; + else if(strstr(input_buffer,"NXDOMAIN")) /* 9.x */ + return STATE_CRITICAL; + + /* Connection was refused */ + else if (strstr (input_buffer, "Connection refused")) + return STATE_CRITICAL; + + /* Network is unreachable */ + else if (strstr (input_buffer, "Network is unreachable")) + return STATE_CRITICAL; + + /* Internal server failure */ + else if (strstr (input_buffer, "Server failure")) + return STATE_CRITICAL; + + /* DNS server refused to service request */ + else if (strstr (input_buffer, "Refused")) + return STATE_CRITICAL; + + /* Request error */ + else if (strstr (input_buffer, "Format error")) + return STATE_WARNING; + + else + return STATE_OK; + +} + +/* process command-line arguments */ +int +process_arguments (int argc, char **argv) +{ + int c; + + if (argc < 2) + return ERROR; + + for (c = 1; c < argc; c++) + if (strcmp ("-to", argv[c]) == 0) + strcpy (argv[c], "-t"); + + c = 0; + while (c += (call_getopt (argc - c, &argv[c]))) { + if (argc <= c) + break; + if (query_address[0] == 0) { + if (is_host (argv[c]) == FALSE) { + printf ("Invalid name/address: %s\n\n", argv[c]); + return ERROR; + } + if (strlen (argv[c]) >= ADDRESS_LENGTH) + terminate (STATE_UNKNOWN, "Input buffer overflow\n"); + strcpy (query_address, argv[c]); + } + else if (dns_server[0] == 0) { + if (is_host (argv[c]) == FALSE) { + printf ("Invalid name/address: %s\n\n", argv[c]); + return ERROR; + } + if (strlen (argv[c]) >= ADDRESS_LENGTH) + terminate (STATE_UNKNOWN, "Input buffer overflow\n"); + strcpy (dns_server, argv[c]); + } + } + + return validate_arguments (); + +} + +int +call_getopt (int argc, char **argv) +{ + int c, i = 1; + +#ifdef HAVE_GETOPT_H + int opt_index = 0; + static struct option long_opts[] = { + {"help", no_argument, 0, 'h'}, + {"version", no_argument, 0, 'V'}, + {"verbose", no_argument, 0, 'v'}, + {"timeout", required_argument, 0, 't'}, + {"hostname", required_argument, 0, 'H'}, + {"server", required_argument, 0, 's'}, + {"reverse-server", required_argument, 0, 'r'}, + {0, 0, 0, 0} + }; +#endif + + + while (1) { +#ifdef HAVE_GETOPT_H + c = getopt_long (argc, argv, "+?hVvt:H:s:r:", long_opts, &opt_index); +#else + c = getopt (argc, argv, "+?hVvt:H:s:r:"); +#endif + + if (c == -1 || c == EOF) + break; + + i++; + switch (c) { + case 't': + case 'H': + case 's': + case 'r': + i++; + } + + switch (c) { + case '?': /* args not parsable */ + printf ("%s: Unknown argument: %s\n\n", my_basename (argv[0]), optarg); + print_usage (my_basename (argv[0])); + exit (STATE_UNKNOWN); + case 'h': /* help */ + print_help (my_basename (argv[0])); + exit (STATE_OK); + case 'V': /* version */ + print_revision (my_basename (argv[0]), "$Revision$"); + exit (STATE_OK); + case 'v': /* version */ + verbose = TRUE; + break; + case 't': /* timeout period */ + timeout_interval = atoi (optarg); + break; + case 'H': /* hostname */ + if (is_host (optarg) == FALSE) { + printf ("Invalid host name/address\n\n"); + print_usage (my_basename (argv[0])); + exit (STATE_UNKNOWN); + } + if (strlen (optarg) >= ADDRESS_LENGTH) + terminate (STATE_UNKNOWN, "Input buffer overflow\n"); + strcpy (query_address, optarg); + break; + case 's': /* server name */ + if (is_host (optarg) == FALSE) { + printf ("Invalid server name/address\n\n"); + print_usage (my_basename (argv[0])); + exit (STATE_UNKNOWN); + } + if (strlen (optarg) >= ADDRESS_LENGTH) + terminate (STATE_UNKNOWN, "Input buffer overflow\n"); + strcpy (dns_server, optarg); + break; + case 'r': /* reverse server name */ + if (is_host (optarg) == FALSE) { + printf ("Invalid host name/address\n\n"); + print_usage (my_basename (argv[0])); + exit (STATE_UNKNOWN); + } + if (strlen (optarg) >= ADDRESS_LENGTH) + terminate (STATE_UNKNOWN, "Input buffer overflow\n"); + strcpy (ptr_server, optarg); + break; + } + } + return i; +} + +int +validate_arguments () +{ + if (query_address[0] == 0) + return ERROR; + else + return OK; +} + +void +print_usage (char *cmd) +{ + printf ("Usage: %s -H host [-s server] [-t timeout]\n" " %s --help\n" + " %s --version\n", cmd, cmd, cmd); +} + +void +print_help (char *cmd) +{ + print_revision (cmd, "$Revision$"); + printf ("Copyright (c) 1999 Ethan Galstad (nagios@nagios.org)\n\n"); + print_usage (cmd); + printf ("\n"); + printf + ("-H, --hostname=HOST\n" + " The name or address you want to query\n" + "-s, --server=HOST\n" + " Optional DNS server you want to use for the lookup\n" + "-t, --timeout=INTEGER\n" + " Seconds before connection times out (default: %d)\n" + "-h, --help\n" + " Print detailed help\n" + "-V, --version\n" + " Print version numbers and license information\n" + "\n" + "This plugin uses the nslookup program to obtain the IP address\n" + "for the given host/domain query. A optional DNS server to use may\n" + "be specified. If no DNS server is specified, the default server(s)\n" + "specified in /etc/resolv.conf will be used.\n", DEFAULT_SOCKET_TIMEOUT); +} |