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-rw-r--r--plugins/check_dns.c619
1 files changed, 619 insertions, 0 deletions
diff --git a/plugins/check_dns.c b/plugins/check_dns.c
new file mode 100644
index 0000000..7ffce98
--- /dev/null
+++ b/plugins/check_dns.c
@@ -0,0 +1,619 @@
+/*****************************************************************************
+*
+* Monitoring check_dns plugin
+*
+* License: GPL
+* Copyright (c) 2000-2008 Monitoring Plugins Development Team
+*
+* Description:
+*
+* This file contains the check_dns plugin
+*
+* LIMITATION: nslookup on Solaris 7 can return output over 2 lines, which
+* will not be picked up by this plugin
+*
+*
+* 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_dns";
+const char *copyright = "2000-2008";
+const char *email = "devel@monitoring-plugins.org";
+
+#include "common.h"
+#include "utils.h"
+#include "utils_base.h"
+#include "netutils.h"
+#include "runcmd.h"
+
+int process_arguments (int, char **);
+int validate_arguments (void);
+int error_scan (char *, int *);
+int ip_match_cidr(const char *, const char *);
+unsigned long ip2long(const char *);
+void print_help (void);
+void print_usage (void);
+
+#define ADDRESS_LENGTH 256
+char query_address[ADDRESS_LENGTH] = "";
+char dns_server[ADDRESS_LENGTH] = "";
+char ptr_server[ADDRESS_LENGTH] = "";
+int verbose = FALSE;
+char **expected_address = NULL;
+int expected_address_cnt = 0;
+int expect_nxdomain = FALSE;
+
+int expect_authority = FALSE;
+int all_match = FALSE;
+thresholds *time_thresholds = NULL;
+
+static int
+qstrcmp(const void *p1, const void *p2)
+{
+ /* The actual arguments to this function are "pointers to
+ pointers to char", but strcmp() arguments are "pointers
+ to char", hence the following cast plus dereference */
+ return strcmp(* (char * const *) p1, * (char * const *) p2);
+}
+
+
+int
+main (int argc, char **argv)
+{
+ char *command_line = NULL;
+ char input_buffer[MAX_INPUT_BUFFER];
+ char *address = NULL; /* comma separated str with addrs/ptrs (sorted) */
+ char **addresses = NULL;
+ int n_addresses = 0;
+ char *msg = NULL;
+ char *temp_buffer = NULL;
+ int non_authoritative = FALSE;
+ int result = STATE_UNKNOWN;
+ double elapsed_time;
+ long microsec;
+ struct timeval tv;
+ int parse_address = FALSE; /* This flag scans for Address: but only after Name: */
+ output chld_out, chld_err;
+ size_t i;
+ int is_nxdomain = FALSE;
+
+ setlocale (LC_ALL, "");
+ bindtextdomain (PACKAGE, LOCALEDIR);
+ textdomain (PACKAGE);
+
+ /* Set signal handling and alarm */
+ if (signal (SIGALRM, runcmd_timeout_alarm_handler) == SIG_ERR) {
+ usage_va(_("Cannot catch SIGALRM"));
+ }
+
+ /* Parse extra opts if any */
+ argv=np_extra_opts (&argc, argv, progname);
+
+ if (process_arguments (argc, argv) == ERROR) {
+ usage_va(_("Could not parse arguments"));
+ }
+
+ /* get the command to run */
+ xasprintf (&command_line, "%s %s %s", NSLOOKUP_COMMAND, query_address, dns_server);
+
+ alarm (timeout_interval);
+ gettimeofday (&tv, NULL);
+
+ if (verbose)
+ printf ("%s\n", command_line);
+
+ /* run the command */
+ if((np_runcmd(command_line, &chld_out, &chld_err, 0)) != 0) {
+ msg = (char *)_("nslookup returned an error status");
+ result = STATE_WARNING;
+ }
+
+ /* scan stdout */
+ for(i = 0; i < chld_out.lines; i++) {
+ if (addresses == NULL)
+ addresses = malloc(sizeof(*addresses)*10);
+ else if (!(n_addresses % 10))
+ addresses = realloc(addresses,sizeof(*addresses) * (n_addresses + 10));
+
+ if (verbose)
+ puts(chld_out.line[i]);
+
+ if (strcasestr (chld_out.line[i], ".in-addr.arpa") || strcasestr (chld_out.line[i], ".ip6.arpa")) {
+ if ((temp_buffer = strstr (chld_out.line[i], "name = ")))
+ addresses[n_addresses++] = strdup (temp_buffer + 7);
+ else {
+ msg = (char *)_("Warning plugin error");
+ result = STATE_WARNING;
+ }
+ }
+
+ /* bug ID: 2946553 - Older versions of bind will use all available dns
+ servers, we have to match the one specified */
+ if (strstr (chld_out.line[i], "Server:") && strlen(dns_server) > 0) {
+ temp_buffer = strchr (chld_out.line[i], ':');
+ temp_buffer++;
+
+ /* Strip leading tabs */
+ for (; *temp_buffer != '\0' && *temp_buffer == '\t'; temp_buffer++)
+ /* NOOP */;
+
+ strip(temp_buffer);
+ if (temp_buffer==NULL || strlen(temp_buffer)==0) {
+ die (STATE_CRITICAL,
+ _("DNS CRITICAL - '%s' returned empty server string\n"),
+ NSLOOKUP_COMMAND);
+ }
+
+ if (strcmp(temp_buffer, dns_server) != 0) {
+ die (STATE_CRITICAL, _("DNS CRITICAL - No response from DNS %s\n"), dns_server);
+ }
+ }
+
+ /* the server is responding, we just got the host name... */
+ if (strstr (chld_out.line[i], "Name:"))
+ parse_address = TRUE;
+ else if (parse_address == TRUE && (strstr (chld_out.line[i], "Address:") ||
+ strstr (chld_out.line[i], "Addresses:"))) {
+ temp_buffer = index (chld_out.line[i], ':');
+ temp_buffer++;
+
+ /* Strip leading spaces */
+ while (*temp_buffer == ' ')
+ temp_buffer++;
+
+ strip(temp_buffer);
+ if (temp_buffer==NULL || strlen(temp_buffer)==0) {
+ die (STATE_CRITICAL,
+ _("DNS CRITICAL - '%s' returned empty host name string\n"),
+ NSLOOKUP_COMMAND);
+ }
+
+ addresses[n_addresses++] = strdup(temp_buffer);
+ }
+ else if (strstr (chld_out.line[i], _("Non-authoritative answer:"))) {
+ non_authoritative = TRUE;
+ }
+
+
+ result = error_scan (chld_out.line[i], &is_nxdomain);
+ if (result != STATE_OK) {
+ msg = strchr (chld_out.line[i], ':');
+ if(msg) msg++;
+ break;
+ }
+ }
+
+ /* scan stderr */
+ for(i = 0; i < chld_err.lines; i++) {
+ if (verbose)
+ puts(chld_err.line[i]);
+
+ if (error_scan (chld_err.line[i], &is_nxdomain) != STATE_OK) {
+ result = max_state (result, error_scan (chld_err.line[i], &is_nxdomain));
+ msg = strchr(input_buffer, ':');
+ if(msg)
+ msg++;
+ else
+ msg = input_buffer;
+ }
+ }
+
+ if (is_nxdomain && !expect_nxdomain) {
+ die (STATE_CRITICAL, _("Domain '%s' was not found by the server\n"), query_address);
+ }
+
+ if (addresses) {
+ int i,slen;
+ char *adrp;
+ qsort(addresses, n_addresses, sizeof(*addresses), qstrcmp);
+ for(i=0, slen=1; i < n_addresses; i++) {
+ slen += strlen(addresses[i])+1;
+ }
+ adrp = address = malloc(slen);
+ for(i=0; i < n_addresses; i++) {
+ if (i) *adrp++ = ',';
+ strcpy(adrp, addresses[i]);
+ adrp += strlen(addresses[i]);
+ }
+ *adrp = 0;
+ } else
+ die (STATE_CRITICAL,
+ _("DNS CRITICAL - '%s' msg parsing exited with no address\n"),
+ NSLOOKUP_COMMAND);
+
+ /* compare to expected address */
+ if (result == STATE_OK && expected_address_cnt > 0) {
+ result = STATE_CRITICAL;
+ temp_buffer = "";
+ unsigned long expect_match = (1 << expected_address_cnt) - 1;
+ unsigned long addr_match = (1 << n_addresses) - 1;
+
+ for (i=0; i<expected_address_cnt; i++) {
+ int j;
+ /* check if we get a match on 'raw' ip or cidr */
+ for (j=0; j<n_addresses; j++) {
+ if ( strcmp(addresses[j], expected_address[i]) == 0
+ || ip_match_cidr(addresses[j], expected_address[i]) ) {
+ result = STATE_OK;
+ addr_match &= ~(1 << j);
+ expect_match &= ~(1 << i);
+ }
+ }
+
+ /* prepare an error string */
+ xasprintf(&temp_buffer, "%s%s; ", temp_buffer, expected_address[i]);
+ }
+ /* check if expected_address must cover all in addresses and none may be missing */
+ if (all_match && (expect_match != 0 || addr_match != 0))
+ result = STATE_CRITICAL;
+ if (result == STATE_CRITICAL) {
+ /* Strip off last semicolon... */
+ temp_buffer[strlen(temp_buffer)-2] = '\0';
+ xasprintf(&msg, _("expected '%s' but got '%s'"), temp_buffer, address);
+ }
+ }
+
+ if (expect_nxdomain) {
+ if (!is_nxdomain) {
+ result = STATE_CRITICAL;
+ xasprintf(&msg, _("Domain '%s' was found by the server: '%s'\n"), query_address, address);
+ } else {
+ if (address != NULL) free(address);
+ address = "NXDOMAIN";
+ }
+ }
+
+ /* check if authoritative */
+ if (result == STATE_OK && expect_authority && non_authoritative) {
+ result = STATE_CRITICAL;
+ xasprintf(&msg, _("server %s is not authoritative for %s"), dns_server, query_address);
+ }
+
+ microsec = deltime (tv);
+ elapsed_time = (double)microsec / 1.0e6;
+
+ if (result == STATE_OK) {
+ result = get_status(elapsed_time, time_thresholds);
+ if (result == STATE_OK) {
+ printf ("DNS %s: ", _("OK"));
+ } else if (result == STATE_WARNING) {
+ printf ("DNS %s: ", _("WARNING"));
+ } else if (result == STATE_CRITICAL) {
+ printf ("DNS %s: ", _("CRITICAL"));
+ }
+ printf (ngettext("%.3f second response time", "%.3f seconds response time", elapsed_time), elapsed_time);
+ printf (_(". %s returns %s"), query_address, address);
+ if ((time_thresholds->warning != NULL) && (time_thresholds->critical != NULL)) {
+ printf ("|%s\n", fperfdata ("time", elapsed_time, "s",
+ TRUE, time_thresholds->warning->end,
+ TRUE, time_thresholds->critical->end,
+ TRUE, 0, FALSE, 0));
+ } else if ((time_thresholds->warning == NULL) && (time_thresholds->critical != NULL)) {
+ printf ("|%s\n", fperfdata ("time", elapsed_time, "s",
+ FALSE, 0,
+ TRUE, time_thresholds->critical->end,
+ TRUE, 0, FALSE, 0));
+ } else if ((time_thresholds->warning != NULL) && (time_thresholds->critical == NULL)) {
+ printf ("|%s\n", fperfdata ("time", elapsed_time, "s",
+ TRUE, time_thresholds->warning->end,
+ FALSE, 0,
+ TRUE, 0, FALSE, 0));
+ } else
+ printf ("|%s\n", fperfdata ("time", elapsed_time, "s", FALSE, 0, FALSE, 0, TRUE, 0, FALSE, 0));
+ }
+ else if (result == STATE_WARNING)
+ printf (_("DNS WARNING - %s\n"),
+ !strcmp (msg, "") ? _(" Probably a non-existent host/domain") : msg);
+ else if (result == STATE_CRITICAL)
+ printf (_("DNS CRITICAL - %s\n"),
+ !strcmp (msg, "") ? _(" Probably a non-existent host/domain") : msg);
+ else
+ printf (_("DNS UNKNOWN - %s\n"),
+ !strcmp (msg, "") ? _(" Probably a non-existent host/domain") : msg);
+
+ return result;
+}
+
+int
+ip_match_cidr(const char *addr, const char *cidr_ro)
+{
+ char *subnet, *mask_c, *cidr = strdup(cidr_ro);
+ int mask;
+ subnet = strtok(cidr, "/");
+ mask_c = strtok(NULL, "\0");
+ if (!subnet || !mask_c)
+ return FALSE;
+ mask = atoi(mask_c);
+
+ /* https://www.cryptobells.com/verifying-ips-in-a-subnet-in-php/ */
+ return (ip2long(addr) & ~((1 << (32 - mask)) - 1)) == (ip2long(subnet) >> (32 - mask)) << (32 - mask);
+}
+
+unsigned long
+ip2long(const char* src) {
+ unsigned long ip[4];
+ /* http://computer-programming-forum.com/47-c-language/1376ffb92a12c471.htm */
+ return (sscanf(src, "%3lu.%3lu.%3lu.%3lu",
+ &ip[0], &ip[1], &ip[2], &ip[3]) == 4 &&
+ ip[0] < 256 && ip[1] < 256 &&
+ ip[2] < 256 && ip[3] < 256)
+ ? ip[0] << 24 | ip[1] << 16 | ip[2] << 8 | ip[3]
+ : 0;
+}
+
+int
+error_scan (char *input_buffer, int *is_nxdomain)
+{
+
+ const int nxdomain = strstr (input_buffer, "Non-existent") ||
+ strstr (input_buffer, "** server can't find") ||
+ strstr (input_buffer, "** Can't find") ||
+ strstr (input_buffer, "NXDOMAIN");
+ if (nxdomain) *is_nxdomain = TRUE;
+
+ /* 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;
+
+ /* DNS server is not running... */
+ else if (strstr (input_buffer, "No response from server"))
+ die (STATE_CRITICAL, _("No response from DNS %s\n"), dns_server);
+ else if (strstr (input_buffer, "no servers could be reached"))
+ die (STATE_CRITICAL, _("No response from DNS %s\n"), dns_server);
+
+ /* Host name is valid, but server doesn't have records... */
+ else if (strstr (input_buffer, "No records"))
+ die (STATE_CRITICAL, _("DNS %s has no records\n"), dns_server);
+
+ /* Connection was refused */
+ else if (strstr (input_buffer, "Connection refused") ||
+ strstr (input_buffer, "Couldn't find server") ||
+ strstr (input_buffer, "Refused") ||
+ (strstr (input_buffer, "** server can't find") &&
+ strstr (input_buffer, ": REFUSED")))
+ die (STATE_CRITICAL, _("Connection to DNS %s was refused\n"), dns_server);
+
+ /* Query refused (usually by an ACL in the namserver) */
+ else if (strstr (input_buffer, "Query refused"))
+ die (STATE_CRITICAL, _("Query was refused by DNS server at %s\n"), dns_server);
+
+ /* No information (e.g. nameserver IP has two PTR records) */
+ else if (strstr (input_buffer, "No information"))
+ die (STATE_CRITICAL, _("No information returned by DNS server at %s\n"), dns_server);
+
+ /* Network is unreachable */
+ else if (strstr (input_buffer, "Network is unreachable"))
+ die (STATE_CRITICAL, _("Network is unreachable\n"));
+
+ /* Internal server failure */
+ else if (strstr (input_buffer, "Server failure"))
+ die (STATE_CRITICAL, _("DNS failure for %s\n"), dns_server);
+
+ /* Request error or the DNS lookup timed out */
+ else if (strstr (input_buffer, "Format error") ||
+ strstr (input_buffer, "Timed out"))
+ return STATE_WARNING;
+
+ return STATE_OK;
+
+}
+
+
+/* process command-line arguments */
+int
+process_arguments (int argc, char **argv)
+{
+ int c;
+ char *warning = NULL;
+ char *critical = NULL;
+
+ 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'},
+ {"expected-address", required_argument, 0, 'a'},
+ {"expect-nxdomain", no_argument, 0, 'n'},
+ {"expect-authority", no_argument, 0, 'A'},
+ {"all", no_argument, 0, 'L'},
+ {"warning", required_argument, 0, 'w'},
+ {"critical", required_argument, 0, 'c'},
+ {0, 0, 0, 0}
+ };
+
+ if (argc < 2)
+ return ERROR;
+
+ for (c = 1; c < argc; c++)
+ if (strcmp ("-to", argv[c]) == 0)
+ strcpy (argv[c], "-t");
+
+ while (1) {
+ c = getopt_long (argc, argv, "hVvALnt:H:s:r:a:w:c:", long_opts, &opt_index);
+
+ if (c == -1 || c == EOF)
+ break;
+
+ switch (c) {
+ case 'h': /* help */
+ print_help ();
+ exit (STATE_UNKNOWN);
+ case 'V': /* version */
+ print_revision (progname, NP_VERSION);
+ exit (STATE_UNKNOWN);
+ case 'v': /* version */
+ verbose = TRUE;
+ break;
+ case 't': /* timeout period */
+ timeout_interval = atoi (optarg);
+ break;
+ case 'H': /* hostname */
+ if (strlen (optarg) >= ADDRESS_LENGTH)
+ die (STATE_UNKNOWN, _("Input buffer overflow\n"));
+ strcpy (query_address, optarg);
+ break;
+ case 's': /* server name */
+ /* TODO: this host_or_die check is probably unnecessary.
+ * Better to confirm nslookup response matches */
+ host_or_die(optarg);
+ if (strlen (optarg) >= ADDRESS_LENGTH)
+ die (STATE_UNKNOWN, _("Input buffer overflow\n"));
+ strcpy (dns_server, optarg);
+ break;
+ case 'r': /* reverse server name */
+ /* TODO: Is this host_or_die necessary? */
+ host_or_die(optarg);
+ if (strlen (optarg) >= ADDRESS_LENGTH)
+ die (STATE_UNKNOWN, _("Input buffer overflow\n"));
+ strcpy (ptr_server, optarg);
+ break;
+ case 'a': /* expected address */
+ if (strlen (optarg) >= ADDRESS_LENGTH)
+ die (STATE_UNKNOWN, _("Input buffer overflow\n"));
+ if (strchr(optarg, ',') != NULL) {
+ char *comma = strchr(optarg, ',');
+ while (comma != NULL) {
+ expected_address = (char **)realloc(expected_address, (expected_address_cnt+1) * sizeof(char**));
+ expected_address[expected_address_cnt] = strndup(optarg, comma - optarg);
+ expected_address_cnt++;
+ optarg = comma + 1;
+ comma = strchr(optarg, ',');
+ }
+ expected_address = (char **)realloc(expected_address, (expected_address_cnt+1) * sizeof(char**));
+ expected_address[expected_address_cnt] = strdup(optarg);
+ expected_address_cnt++;
+ } else {
+ expected_address = (char **)realloc(expected_address, (expected_address_cnt+1) * sizeof(char**));
+ expected_address[expected_address_cnt] = strdup(optarg);
+ expected_address_cnt++;
+ }
+ break;
+ case 'n': /* expect NXDOMAIN */
+ expect_nxdomain = TRUE;
+ break;
+ case 'A': /* expect authority */
+ expect_authority = TRUE;
+ break;
+ case 'L': /* all must match */
+ all_match = TRUE;
+ break;
+ case 'w':
+ warning = optarg;
+ break;
+ case 'c':
+ critical = optarg;
+ break;
+ default: /* args not parsable */
+ usage5();
+ }
+ }
+
+ c = optind;
+ if (strlen(query_address)==0 && c<argc) {
+ if (strlen(argv[c])>=ADDRESS_LENGTH)
+ die (STATE_UNKNOWN, _("Input buffer overflow\n"));
+ strcpy (query_address, argv[c++]);
+ }
+
+ if (strlen(dns_server)==0 && c<argc) {
+ /* TODO: See -s option */
+ host_or_die(argv[c]);
+ if (strlen(argv[c]) >= ADDRESS_LENGTH)
+ die (STATE_UNKNOWN, _("Input buffer overflow\n"));
+ strcpy (dns_server, argv[c++]);
+ }
+
+ set_thresholds(&time_thresholds, warning, critical);
+
+ return validate_arguments ();
+}
+
+
+int
+validate_arguments ()
+{
+ if (query_address[0] == 0) {
+ printf ("missing --host argument\n");
+ return ERROR;
+ }
+
+ if (expected_address_cnt > 0 && expect_nxdomain) {
+ printf ("--expected-address and --expect-nxdomain cannot be combined\n");
+ return ERROR;
+ }
+
+ return OK;
+}
+
+
+void
+print_help (void)
+{
+ print_revision (progname, NP_VERSION);
+
+ printf ("Copyright (c) 1999 Ethan Galstad <nagios@nagios.org>\n");
+ printf (COPYRIGHT, copyright, email);
+
+ printf ("%s\n", _("This plugin uses the nslookup program to obtain the IP address for the given host/domain query."));
+ printf ("%s\n", _("An optional DNS server to use may be specified."));
+ printf ("%s\n", _("If no DNS server is specified, the default server(s) specified in /etc/resolv.conf will be used."));
+
+ printf ("\n\n");
+
+ print_usage ();
+
+ printf (UT_HELP_VRSN);
+ printf (UT_EXTRA_OPTS);
+
+ printf (" -H, --hostname=HOST\n");
+ printf (" %s\n", _("The name or address you want to query"));
+ printf (" -s, --server=HOST\n");
+ printf (" %s\n", _("Optional DNS server you want to use for the lookup"));
+ printf (" -a, --expected-address=IP-ADDRESS|CIDR|HOST\n");
+ printf (" %s\n", _("Optional IP-ADDRESS/CIDR you expect the DNS server to return. HOST must end"));
+ printf (" %s\n", _("with a dot (.). This option can be repeated multiple times (Returns OK if any"));
+ printf (" %s\n", _("value matches)."));
+ printf (" -n, --expect-nxdomain\n");
+ printf (" %s\n", _("Expect the DNS server to return NXDOMAIN (i.e. the domain was not found)"));
+ printf (" %s\n", _("Cannot be used together with -a"));
+ printf (" -A, --expect-authority\n");
+ printf (" %s\n", _("Optionally expect the DNS server to be authoritative for the lookup"));
+ printf (" -w, --warning=seconds\n");
+ printf (" %s\n", _("Return warning if elapsed time exceeds value. Default off"));
+ printf (" -c, --critical=seconds\n");
+ printf (" %s\n", _("Return critical if elapsed time exceeds value. Default off"));
+ printf (" -L, --all\n");
+ printf (" %s\n", _("Return critical if the list of expected addresses does not match all addresses"));
+ printf (" %s\n", _("returned. Default off"));
+
+ printf (UT_CONN_TIMEOUT, DEFAULT_SOCKET_TIMEOUT);
+
+ printf (UT_SUPPORT);
+}
+
+
+void
+print_usage (void)
+{
+ printf ("%s\n", _("Usage:"));
+ printf ("%s -H host [-s server] [-a expected-address] [-n] [-A] [-t timeout] [-w warn] [-c crit] [-L]\n", progname);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-22 03:56:30 +0000