1 files changed, 110 insertions, 0 deletions
diff --git a/wsutil/inet_cidr.c b/wsutil/inet_cidr.c
new file mode 100644
index 00000000..89777e16
--- /dev/null
+++ b/wsutil/inet_cidr.c
@@ -0,0 +1,110 @@
+/* ipv4.c
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "inet_cidr.h"
+
+
+uint32_t
+ws_ipv4_get_subnet_mask(const uint32_t mask_length)
+{
+	static const uint32_t masks[33] = {
+		0x00000000,
+		0x80000000, 0xc0000000, 0xe0000000, 0xf0000000,
+		0xf8000000, 0xfc000000, 0xfe000000, 0xff000000,
+		0xff800000, 0xffc00000, 0xffe00000, 0xfff00000,
+		0xfff80000, 0xfffc0000, 0xfffe0000, 0xffff0000,
+		0xffff8000, 0xffffc000, 0xffffe000, 0xfffff000,
+		0xfffff800, 0xfffffc00, 0xfffffe00, 0xffffff00,
+		0xffffff80, 0xffffffc0, 0xffffffe0, 0xfffffff0,
+		0xfffffff8, 0xfffffffc, 0xfffffffe, 0xffffffff,
+	};
+
+	ws_assert(mask_length <= 32);
+
+	return masks[mask_length];
+}
+
+static int
+compare_ipv4(const ipv4_addr_and_mask *a, const ipv4_addr_and_mask *b)
+{
+    uint32_t addr_a, addr_b, nmask;
+
+    nmask = MIN(a->nmask, b->nmask);
+    addr_a = a->addr & nmask;
+    addr_b = b->addr & nmask;
+    if (addr_a < addr_b)
+        return -1;
+    if (addr_a > addr_b)
+        return 1;
+    return 0;
+}
+
+void
+ws_ipv4_addr_and_mask_init(ipv4_addr_and_mask *dst, ws_in4_addr src_addr, int src_bits)
+{
+    dst->addr = g_ntohl(src_addr);
+    dst->nmask = ws_ipv4_get_subnet_mask(src_bits);
+}
+
+bool
+ws_ipv4_addr_and_mask_contains(const ipv4_addr_and_mask *ipv4, const ws_in4_addr *in_addr)
+{
+    ipv4_addr_and_mask addr_and_mask;
+
+    addr_and_mask.addr = g_ntohl(*in_addr);
+    addr_and_mask.nmask = ws_ipv4_get_subnet_mask(32);
+    return compare_ipv4(ipv4, &addr_and_mask) == 0;
+}
+
+static const uint8_t bitmasks[9] =
+    { 0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff };
+
+static int
+compare_ipv6(const ipv6_addr_and_prefix *a, const ipv6_addr_and_prefix *b)
+{
+    uint32_t prefix;
+    int pos = 0;
+
+    prefix = MIN(a->prefix, b->prefix);	/* MIN() like IPv4 */
+    prefix = MIN(prefix, 128);		/* sanitize, max prefix is 128 */
+
+    while (prefix >= 8) {
+        int byte_a = (int) (a->addr.bytes[pos]);
+        int byte_b = (int) (b->addr.bytes[pos]);
+
+        if (byte_a != byte_b) {
+            return byte_a - byte_b;
+        }
+
+        prefix -= 8;
+        pos++;
+    }
+
+    if (prefix != 0) {
+        int byte_a = (int) (a->addr.bytes[pos] & (bitmasks[prefix]));
+        int byte_b = (int) (b->addr.bytes[pos] & (bitmasks[prefix]));
+
+        if (byte_a != byte_b) {
+            return byte_a - byte_b;
+        }
+    }
+
+    return 0;
+}
+
+
+bool
+ws_ipv6_addr_and_prefix_contains(const ipv6_addr_and_prefix *ipv6, const ws_in6_addr *in_addr)
+{
+    ipv6_addr_and_prefix addr_and_mask;
+
+    addr_and_mask.addr = *in_addr;
+    addr_and_mask.prefix = 128;
+    return compare_ipv6(ipv6, &addr_and_mask) == 0;
+}