introduce -A arg: treat single subnets as shared-network with CIDR as their name

Current output makes some false-positives for situations when multiple
ranges are specified inside single network, for example:

subnet 10.0.0.0 netmask 255.255.254.0 {
	...
	range 10.0.0.1 10.0.0.254;
	range 10.0.1.1 10.0.1.253;
	...
}

An alert for range 10.0.0.1 - 10.0.0.254 will be raised even in situations
when range 10.0.1.1 - 10.0.1.253 is completely empty.  To cope with this
issue, an -A option is added to treat all single networks as shared-network.
This option changes output for both range and shared networks output if
specified.  Frankly saying, using network CIDR as network name is much more
sane for me than 'All Networks'.

Signed-off-by: Boris Lytochkin <lytboris@yandex-team.ru>

THANKS

@@ -40,3 +40,4 @@ Derrick Lin
 Ivanov Ivan
 Manuel Hachtkemper
 Klaus Slott
+Boris Lytochkin

man/dhcpd-pools.1.in

@@ -202,6 +202,10 @@ backup leases.  This option is meaningful only in context of alarming and
 will print lots of data, if there are many networks.  By default this option
 is not in use.
 .TP
+\fB\-A\fR, \fB\-\-all\-as\-shared\fR
+Treat all stand-alone subnets as shared-network with named formed from it's
+CIDR.  By default this option is not in use for backwards compatibility.
+.TP
 \fB\-v\fR, \fB\-\-version\fR
 Print version information to standard output and exit successfully.
 .TP

src/dhcpd-pools.c

@@ -129,6 +129,7 @@ int main(int argc, char **argv)
 		{"crit-count", required_argument, NULL, OPT_CRIT_COUNT},
 		{"minsize", required_argument, NULL, OPT_MINSIZE},
 		{"perfdata", no_argument, NULL, 'p'},
+		{"all-as-shared", no_argument, NULL, 'A'},
 		{NULL, 0, NULL, 0}
 	};
 
@@ -161,12 +162,14 @@ int main(int argc, char **argv)
 	/* Default sort order is by IPs small to big */
 	config.reverse_order = 0;
 	config.backups_found = 0;
+	/* Treat single networks as shared with network CIDR as name */
+	config.all_as_shared = 0;
 	prepare_memory();
 	/* Parse command line options */
 	while (1) {
 		int c;
 
-		c = getopt_long(argc, argv, "c:l:f:o:s:rL:pvh", long_options, &option_index);
+		c = getopt_long(argc, argv, "c:l:f:o:s:rL:pAvh", long_options, &option_index);
 		if (c == EOF)
 			break;
 		switch (c) {
@@ -241,6 +244,10 @@ int main(int argc, char **argv)
 			/* Print additional performance data in alarming mode */
 			config.perfdata = 1;
 			break;
+		case 'A':
+			/* Treat single networks as shared with network CIDR as name */
+			config.all_as_shared = 1;
+			break;
 		case 'v':
 			/* Print version */
 			print_version();

src/dhcpd-pools.h

@@ -108,6 +108,7 @@ struct shared_network_t {
 	double used;
 	double touched;
 	double backups;
+	int netmask;
 };
 /*! \struct range_t
  * \brief Counters for an individual range.
@@ -128,7 +129,9 @@ enum isc_conf_parser {
 	ITS_A_RANGE_FIRST_IP,
 	ITS_A_RANGE_SECOND_IP,
 	ITS_A_SHAREDNET,
-	ITS_AN_INCLUCE
+	ITS_AN_INCLUCE,
+	ITS_A_SUBNET,
+	ITS_A_NETMASK
 };
 /*! \enum ltype
  * \brief Lease state types.
@@ -196,6 +199,7 @@ struct configuration_t {
 		snet_alarms:1,
 		print_mac_addreses:1,
 		perfdata:1,
+		all_as_shared:1,
 		header_limit:3,
 		number_limit:3;
 };

src/getdata.c

@@ -153,6 +153,12 @@ static int is_interesting_config_clause(char const *restrict s)
 		return ITS_A_RANGE_FIRST_IP;
 	if (strstr(s, "shared-network"))
 		return ITS_A_SHAREDNET;
+	if (config.all_as_shared) {
+		if (strstr(s, "subnet"))
+			return ITS_A_SUBNET;
+		if (strstr(s, "netmask"))
+			return ITS_A_NETMASK;
+	}
 	if (strstr(s, "include"))
 		return ITS_AN_INCLUCE;
 	return ITS_NOTHING_INTERESTING;
@@ -364,6 +370,12 @@ void parse_config(int is_include, const char *restrict config_file,
 				argument = ITS_A_RANGE_SECOND_IP;
 				break;
 			case ITS_A_SHAREDNET:
+			case ITS_A_SUBNET:
+				/* ignore subnets inside a shared-network */
+				if (argument == ITS_A_SUBNET && shared_p != shared_networks) {
+					argument = ITS_NOTHING_INTERESTING;
+					break;
+				}
 				/* printf ("shared-network named: %s\n", word); */
 				num_shared_networks++;
 				shared_p = shared_networks + num_shared_networks;
@@ -372,10 +384,32 @@ void parse_config(int is_include, const char *restrict config_file,
 				shared_p->used = 0;
 				shared_p->touched = 0;
 				shared_p->backups = 0;
+				shared_p->netmask = (argument == ITS_A_SUBNET ? -1 : 0); /* do not fill in netmask */
 				if (SHARED_NETWORKS < num_shared_networks + 2)
 					/* FIXME: make this to go away by reallocating more space. */
 					error(EXIT_FAILURE, 0,
 					      "parse_config: increase default.h SHARED_NETWORKS and recompile");
+				/* record network's mask too */
+				if (argument == ITS_A_SUBNET)
+				        newclause = 1;
+				argument = ITS_NOTHING_INTERESTING;
+				braces_shared = braces;
+				break;
+			case ITS_A_NETMASK:
+				/* fill in only when requested to do so */
+				if (shared_p->netmask) {
+					if (!(parse_ipaddr(word, &addr)))
+						break;
+					shared_p->netmask = 32;
+					while ((addr.v4 & 0x01) == 0) {
+						addr.v4 >>= 1;
+						shared_p->netmask--;
+					}
+					snprintf(word, MAXLEN-1, "%s/%d", shared_p->name, shared_p->netmask);
+					if (shared_p->name)
+						free(shared_p->name);
+					shared_p->name = xstrdup(word);
+				}
 				argument = ITS_NOTHING_INTERESTING;
 				braces_shared = braces;
 				break;

src/other.c

@@ -474,7 +474,8 @@ void __attribute__ ((__noreturn__)) usage(int status)
 	fputs(		"      --crit-count=NR    a number of free leases before critical raised\n", out);
 	fputs(		"      --minsize=size     disable alarms for small ranges and shared-nets\n", out);
 	fputs(		"      --snet-alarms      suppress range alarms that are part of a shared-net\n", out);
-	fputs(		"  -p  --perfdata         print additional perfdata in alarming mode\n", out);
+	fputs(		"  -p, --perfdata         print additional perfdata in alarming mode\n", out);
+	fputs(		"  -A, --all-as-shared    treat single subnets as shared-network with CIDR as their name\n", out);
 	fputs(		"  -v, --version          output version information and exit\n", out);
 	fputs(		"  -h, --help             display this help and exit\n", out);
 	fputs(		"\n", out);