getdata: add cidr range support

This makes 'range6 123::/45' style cidr notation to be understood as address
range.  Earlier ranges that used cidr failed to parse completely.

Reported-by: Jeff Bailey <jeffrey.bailey@bt.com>
Signed-off-by: Sami Kerola <kerolasa@iki.fi>

src/dhcpd-pools.h

@@ -238,6 +238,8 @@ extern int parse_ipaddr_init(const char *restrict src,
 extern int parse_ipaddr_v4(const char *restrict src, union ipaddr_t *restrict dst);
 extern int parse_ipaddr_v6(const char *restrict src, union ipaddr_t *restrict dst);
 
+extern void parse_cidr(struct range_t *range_p, const char *word);
+
 extern void (*copy_ipaddr) (union ipaddr_t *restrict dst, const union ipaddr_t *restrict src);
 extern void copy_ipaddr_init(union ipaddr_t *restrict dst,
 			     const union ipaddr_t *restrict src);

src/getdata.c

@@ -339,13 +339,19 @@ void parse_config(int is_include, const char *restrict config_file,
 				/* printf ("range 2nd ip: %s\n", word); */
 				range_p = ranges + num_ranges;
 				argument = ITS_NOTHING_INTERESTING;
-				parse_ipaddr(word, &addr);
-				if (one_ip_range == 1) {
+				if (strchr(word, '/')) {
+					parse_cidr(range_p, word);
 					one_ip_range = 0;
-					copy_ipaddr(&range_p->first_ip, &addr);
+				} else {
+					/* not cidr */
+					parse_ipaddr(word, &addr);
+					if (one_ip_range == 1) {
+						one_ip_range = 0;
+						copy_ipaddr(&range_p->first_ip, &addr);
+					}
+					copy_ipaddr(&range_p->last_ip, &addr);
+					reorder_last_first(range_p);
 				}
-				copy_ipaddr(&range_p->last_ip, &addr);
-				reorder_last_first(range_p);
  newrange:
 				range_p->count = 0;
 				range_p->touched = 0;

src/other.c

@@ -52,10 +52,15 @@
 #include "error.h"
 #include "progname.h"
 #include "quote.h"
+#include "xalloc.h"
 
 #include "dhcpd-pools.h"
 #include "defaults.h"
 
+char *(*cidr_last)(union ipaddr_t *restrict addr, const int mask);
+static char *cidr_last_v4(union ipaddr_t *restrict addr, const int mask);
+static char *cidr_last_v6(union ipaddr_t *restrict addr, const int mask);
+
 /*! \brief Set function pointers depending on IP version.
  * \param ip IP version.
  */
@@ -73,6 +78,7 @@ void set_ipv_functions(int version)
 		leasecomp = leasecomp_v4;
 		ntop_ipaddr = ntop_ipaddr_v4;
 		parse_ipaddr = parse_ipaddr_v4;
+		cidr_last = cidr_last_v4;
 		xstrstr = xstrstr_v4;
 		break;
 
@@ -86,6 +92,7 @@ void set_ipv_functions(int version)
 		leasecomp = leasecomp_v6;
 		ntop_ipaddr = ntop_ipaddr_v6;
 		parse_ipaddr = parse_ipaddr_v6;
+		cidr_last = cidr_last_v6;
 		xstrstr = xstrstr_v6;
 		break;
 
@@ -99,6 +106,7 @@ void set_ipv_functions(int version)
 		leasecomp = leasecomp_init;
 		ntop_ipaddr = ntop_ipaddr_init;
 		parse_ipaddr = parse_ipaddr_init;
+		cidr_last = NULL;
 		xstrstr = xstrstr_init;
 		break;
 
@@ -148,6 +156,92 @@ int parse_ipaddr_v6(const char *restrict src, union ipaddr_t *restrict dst)
 	return rv == 1;
 }
 
+static int strtol_mask(const char *str)
+{
+	long num;
+	char *end = NULL;
+
+	errno = 0;
+	if (str == NULL || *str == '\0')
+		goto err;
+	num = strtol(str, &end, 10);
+
+	if (errno || str == end || (end && *end))
+		goto err;
+	if (num < 0 || 128 < num)
+		goto err;
+	return (int)num;
+ err:
+	return -1;
+}
+
+static char *cidr_last_v4(union ipaddr_t *restrict addr, const int mask)
+{
+	union ipaddr_t last_ip;
+	uint32_t netmask;
+	const char *ip;
+
+	if (mask)
+		netmask = (1U << (32 - mask)) - 1;
+	else
+		netmask = 0;
+	last_ip.v4 =  addr->v4 | netmask;
+
+	ip = ntop_ipaddr(&last_ip);
+	return xstrdup(ip);
+}
+
+static char *cidr_last_v6(union ipaddr_t *restrict addr, const int mask)
+{
+	union ipaddr_t bitmask;
+	int i, j;
+	char ip[128];
+
+	memset(&bitmask, 0x0, sizeof(bitmask));
+	for (i = mask, j = 0; i > 0; i -= 8, j++) {
+		if (i >= 8)
+			bitmask.v6[j] = 0xff;
+		else
+			bitmask.v6[j] = (unsigned char)(0xffU << (8 - i));
+	}
+	for (i = 0; i < (int)sizeof(bitmask); i++)
+		addr->v6[i] |= ~bitmask.v6[i];
+	inet_ntop(AF_INET6, addr, ip, sizeof(ip));
+	return xstrdup(ip);
+}
+
+void parse_cidr(struct range_t *range_p, const char *word)
+{
+	char *divider;
+	int mask;
+	union ipaddr_t addr;
+	char *last;
+
+	/* determine cidr */
+	divider = strchr(word, '/');
+	*divider++ = '\0';
+	mask = strtol_mask(divider);
+	if (mask < 0)
+		error(EXIT_FAILURE, 0, "cidr %s invalid mask %s", word,
+		      divider);
+	if (config.ip_version == IPvUNKNOWN) {
+		if (!strchr(word, ':'))
+			set_ipv_functions(IPv4);
+		else
+			set_ipv_functions(IPv6);
+	}
+
+	/* start of the range is easy */
+	parse_ipaddr(word, &addr);
+	copy_ipaddr(&range_p->first_ip, &addr);
+
+	/* end of the range depends cidr size */
+	last = cidr_last(&addr, mask);
+	parse_ipaddr(last, &addr);
+	copy_ipaddr(&range_p->last_ip, &addr);
+	free(last);
+}
+
 /*! \brief Copy IP address to union.
  *
  * \param dst Destination for a binary IP address.