output: add json format support

Reviewed-by: Sami Kerola <kerolasa@iki.fi>
Signed-off-by: Gilles Bouthenot <gilles.bouthenot@univ-fcomte.fr>

THANKS

@@ -24,3 +24,4 @@ Robert Viou
 Enno Gröper
 Ryan Malek
 Cheer Xiao
+Gilles Bouthenot

man/dhcpd-pools.1.in

@@ -62,7 +62,7 @@ are equal next one is used.  The IP field is default sort key.
 \fB\-r\fR, \fB\-\-reverse\fR
 Sort results in reverse order.
 .TP
-\fB\-f\fR, \fB\-\-format\fR=\fI[thHcxX]\fR
+\fB\-f\fR, \fB\-\-format\fR=\fI[thHcxXjJ]\fR
 Output format.
 Text
 .RI ( t ).
@@ -77,7 +77,11 @@ stands for comma-separated values.  Output format xml
 .RI ( x )
 is similar to the dhcpstatus Perl module output.  The extended xml
 .RI ( X )
-format will print ethernet address details.
+format will print ethernet address details.  The
+.RI ( j )
+will output in json format, which can be extended with
+.RI ( J )
+to include ethernet address.
 .IP
 The default format is
 .IR @OUTPUT_FORMAT@ .

src/dhcpd-pools.c

@@ -207,6 +207,12 @@ int main(int argc, char **argv)
 	case 'X':
 		output_analysis = output_xml;
 		break;
+	case 'j':
+		output_analysis = output_json;
+		break;
+	case 'J':
+		output_analysis = output_json;
+		break;
 	case 'c':
 		output_analysis = output_csv;
 		break;

src/dhcpd-pools.h

@@ -194,6 +194,7 @@ int (*output_analysis) (void);
 int output_txt(void);
 int output_html(void);
 int output_xml(void);
+int output_json(void);
 int output_csv(void);
 int output_alarming(void);
 /* Memory release, file closing etc */

src/getdata.c

@@ -119,7 +119,7 @@ int parse_leases(void)
 
 	line = xmalloc(sizeof(char) * MAXLEN);
 	ipstring = xmalloc(sizeof(char) * MAXLEN);
-	if (config.output_format[0] == 'X') {
+	if (config.output_format[0] == 'X' || config.output_format[0] == 'J') {
 		macstring = xmalloc(sizeof(char) * 18);
 		macaddr = xmalloc(sizeof(struct macaddr_t));
 		macaddr_p = macaddr;

src/other.c

@@ -219,13 +219,16 @@ This is ISC dhcpd pools usage analyzer.\n\
 \n", program_invocation_short_name);
 	fprintf(out, "\
   -c, --config=FILE      path to the dhcpd.conf file\n\
-  -l, --leases=FILE      path to the dhcpd.leases file\n\
-  -f, --format=[thHcxX]  output format\n\
+  -l, --leases=FILE      path to the dhcpd.leases file\n");
+	fprintf(out, "\
+  -f, --format=[thHcxXjJ] output format\n\
                            t for text\n\
                            h for html table\n\
                            H for full html page\n\
                            x for xml\n\
                            X for xml with active lease details\n\
+                           j for json\n\
+                           J for json with active lease details\n\
                            c for comma separated values\n");
 	fprintf(out, "\
   -s, --sort=[nimcptTe]  sort ranges by\n\

src/output.c

@@ -322,6 +322,142 @@ int output_xml(void)
 	return 0;
 }
 
+int output_json(void)
+{
+	unsigned int i;
+	struct range_t *range_p;
+	unsigned long range_size;
+	struct shared_network_t *shared_p;
+	struct macaddr_t *macaddr_p;
+	int ret;
+	FILE *outfile;
+	char sep;
+
+	if (config.output_file[0]) {
+		outfile = fopen(config.output_file, "w+");
+		if (outfile == NULL) {
+			err(EXIT_FAILURE, "output_json: %s",
+			    config.output_file);
+		}
+	} else {
+		outfile = stdout;
+	}
+
+	range_p = ranges;
+	range_size = get_range_size(range_p);
+	shared_p = shared_networks;
+	sep = ' ';
+
+	fprintf(outfile, "{\n");
+
+	if (macaddr != NULL) {
+		fprintf(outfile, "   %c\"active_leases\": [\n", sep);
+		for (i = 0, macaddr_p = macaddr; macaddr_p->next != NULL;
+		     macaddr_p = macaddr_p->next) {
+			if (0 != i) {
+				fprintf(outfile, ",\n         ");
+			} else {
+				fprintf(outfile, "\n         ");
+			}
+			fprintf(outfile,
+				"{ \"ip\":\"%s\", \"macaddress\":\"%s\" }",
+				macaddr_p->ip, macaddr_p->ethernet);
+			i++;
+		}
+		fprintf(outfile, "\n   ]");	/* end of active_leases */
+		sep = ',';
+	}
+
+	if (config.output_limit[1] & output_limit_bit_1) {
+		if (sep == ',')
+			printf(",\n");
+		fprintf(outfile, "   \"subnets\": [\n");
+		for (i = 0; i < num_ranges; i++) {
+			fprintf(outfile, "         ");
+			fprintf(outfile, "{ ");
+			if (range_p->shared_net) {
+				fprintf(outfile,
+					"\"location\":\"%s\", ",
+					range_p->shared_net->name);
+			} else {
+				fprintf(outfile, "\"location\":\"\", ");
+			}
+
+			fprintf(outfile, "\"network\":\"\", ");
+			fprintf(outfile, "\"netmask\":\"\", ");
+			fprintf(outfile, "\"range\":\"%s\", ",
+				ntop_ipaddr(&range_p->first_ip));
+			fprintf(outfile, "\"gateway\":\"\", ");
+			fprintf(outfile, "\"defined\":%lu, ", range_size);
+			fprintf(outfile, "\"used\":%lu, ", range_p->count);
+			fprintf(outfile, "\"free\":%lu ",
+				range_size - range_p->count);
+			range_p++;
+			range_size = get_range_size(range_p);
+			if (i + 1 < num_ranges)
+				fprintf(outfile, "},\n");
+			else
+				fprintf(outfile, "}\n");
+		}
+		fprintf(outfile, "   ]");	/* end of subnets */
+		sep = ',';
+	}
+
+	if (config.output_limit[1] & output_limit_bit_2) {
+		if (sep == ',')
+			printf(",\n");
+		fprintf(outfile, "   \"shared-networks\": [\n");
+		for (i = 0; i < num_shared_networks; i++) {
+			fprintf(outfile, "         ");
+			shared_p++;
+			fprintf(outfile, "{ ");
+			fprintf(outfile, "\"location\":\"%s\", ",
+				shared_p->name);
+			fprintf(outfile, "\"defined\":%lu, ",
+				shared_p->available);
+			fprintf(outfile, "\"used\":%lu, ", shared_p->used);
+			fprintf(outfile, "\"free\":%lu ",
+				shared_p->available - shared_p->used);
+			if (i + 1 < num_shared_networks)
+				fprintf(outfile, "},\n");
+			else
+				fprintf(outfile, "}\n");
+		}
+		fprintf(outfile, "   ]");	/* end of shared-networks */
+		sep = ',';
+	}
+
+	if (config.output_limit[0] & output_limit_bit_3) {
+		if (sep == ',')
+			printf(",\n");
+		fprintf(outfile, "   \"summary\": {\n");
+		fprintf(outfile, "         \"location\":\"%s\",\n",
+			shared_networks->name);
+		fprintf(outfile, "         \"defined\":%lu,\n",
+			shared_networks->available);
+		fprintf(outfile, "         \"used\":%lu,\n",
+			shared_networks->used);
+		fprintf(outfile, "         \"free\":%lu\n",
+			shared_networks->available - shared_networks->used);
+		fprintf(outfile, "   }");	/* end of summary */
+	}
+
+	fprintf(outfile, "\n}");
+	if (outfile == stdout) {
+		ret = fflush(stdout);
+		if (ret) {
+			warn("output_json: fflush");
+		}
+	} else {
+		ret = close_stream(outfile);
+		if (ret) {
+			warn("output_json: fclose");
+		}
+	}
+
+	return 0;
+}
+
 static void html_header(FILE *restrict f)
 {
 	char outstr[200];