diff options
| -rw-r--r-- | plugins/check_dns.c | 42 |
1 files changed, 37 insertions, 5 deletions
diff --git a/plugins/check_dns.c b/plugins/check_dns.c index 1f43c2ed..4067c14b 100644 --- a/plugins/check_dns.c +++ b/plugins/check_dns.c @@ -42,6 +42,8 @@ const char *email = "devel@monitoring-plugins.org"; int process_arguments (int, char **); int validate_arguments (void); int error_scan (char *); +int ip_match_cidr(const char *, const char *); +unsigned long ip2long(const char *); void print_help (void); void print_usage (void); @@ -226,9 +228,14 @@ main (int argc, char **argv) if (result == STATE_OK && expected_address_cnt > 0) { result = STATE_CRITICAL; temp_buffer = ""; + for (i=0; i<expected_address_cnt; i++) { - /* check if we get a match and prepare an error string */ - if (strcmp(address, expected_address[i]) == 0) result = STATE_OK; + /* check if we get a match on 'raw' ip or cidr */ + if ( strcmp(address, expected_address[i]) == 0 + || ip_match_cidr(address, expected_address[i]) ) + result = STATE_OK; + + /* prepare an error string */ xasprintf(&temp_buffer, "%s%s; ", temp_buffer, expected_address[i]); } if (result == STATE_CRITICAL) { @@ -289,7 +296,32 @@ main (int argc, char **argv) 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) @@ -494,9 +526,9 @@ print_help (void) 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|HOST\n"); - printf (" %s\n", _("Optional IP-ADDRESS you expect the DNS server to return. HOST must end with")); - printf (" %s\n", _("a dot (.). This option can be repeated multiple times (Returns OK if any")); + 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 match). If multiple addresses are returned at once, you have to match")); printf (" %s\n", _("the whole string of addresses separated with commas (sorted alphabetically).")); printf (" -A, --expect-authority\n"); |