filter: CIDR-based filtering support

This patch adds CIDR-based filtering support. The current
implementation is O(n).

This patch also introduces the vector data type which is
used to store the IP address and the network mask.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 88 insertions, 0 deletions

diff --git a/src/vector.c b/src/vector.c
new file mode 100644
index 0000000..c81e7ce
--- /dev/null
+++ b/src/vector.c
@@ -0,0 +1,88 @@
+/*
+ * (C) 2006-2008 by Pablo Neira Ayuso <pablo@netfilter.org>
+ * 
+ * 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 2 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, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include "vector.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+struct vector {
+	char *data;
+	unsigned int cur_elems;
+	unsigned int max_elems;
+	size_t size;
+};
+
+#define DEFAULT_VECTOR_MEMBERS	8
+#define DEFAULT_VECTOR_GROWTH	8
+
+struct vector *vector_create(size_t size)
+{
+	struct vector *v;
+
+	v = calloc(sizeof(struct vector), 1);
+	if (v == NULL)
+		return NULL;
+
+	v->size = size;
+	v->cur_elems = 0;
+	v->max_elems = DEFAULT_VECTOR_MEMBERS;
+
+	v->data = calloc(size * DEFAULT_VECTOR_MEMBERS, 1);
+	if (v->data == NULL) {
+		free(v);
+		return NULL;
+	}
+
+	return v;
+}
+
+void vector_destroy(struct vector *v)
+{
+	free(v->data);
+	free(v);
+}
+
+int vector_add(struct vector *v, void *data)
+{
+	if (v->cur_elems >= v->max_elems) {
+		v->max_elems += DEFAULT_VECTOR_GROWTH;
+		v->data = realloc(v->data, v->max_elems * v->size);
+		if (v->data == NULL) {
+			v->max_elems -= DEFAULT_VECTOR_GROWTH;
+			return -1;
+		}
+	}
+	memcpy(v->data + (v->size * v->cur_elems), data, v->size);
+	v->cur_elems++;
+	return 0;
+}
+
+int vector_iterate(struct vector *v,
+		   const void *data,
+		   int (*fcn)(const void *a, const void *b))
+{
+	unsigned int i;
+
+	for (i=0; i<v->cur_elems; i++) {
+		char *ptr = v->data + (v->size * i);
+		if (fcn(ptr, data))
+			return 1;
+	}
+	return 0;
+}