Major rework of the user-space event filtering

This patch reworks the user-space filtering. Although we have
kernel-space filtering since Linux kernel >= 2.6.26, we keep userspace
filtering to ensure backward compatibility. Moreover, this patch
prepares the implementation of the kernel-space filtering via
libnetfilter_conntrack's high-level berkeley socket filter API.

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

1 files changed, 36 insertions, 0 deletions

diff --git a/include/bitops.h b/include/bitops.h
new file mode 100644
index 0000000..51f4289
--- /dev/null
+++ b/include/bitops.h
@@ -0,0 +1,36 @@
+#ifndef _BITOPS_H_
+#define _BITOPS_H_
+
+#include <stdlib.h>
+
+static inline void set_bit_u32(int nr, u_int32_t *addr)
+{
+	addr[nr >> 5] |= (1UL << (nr & 31));
+}
+
+static inline void unset_bit_u32(int nr, u_int32_t *addr)
+{
+	addr[nr >> 5] &= ~(1UL << (nr & 31));
+}
+
+static inline int test_bit_u32(int nr, const u_int32_t *addr)
+{
+	return ((1UL << (nr & 31)) & (addr[nr >> 5])) != 0;
+}
+
+static inline void set_bit_u16(int nr, u_int16_t *addr)
+{
+	addr[nr >> 4] |= (1UL << (nr & 15));
+}
+
+static inline void unset_bit_u16(int nr, u_int16_t *addr)
+{
+	addr[nr >> 4] &= ~(1UL << (nr & 15));
+}
+
+static inline int test_bit_u16(int nr, const u_int16_t *addr)
+{
+	return ((1UL << (nr & 15)) & (addr[nr >> 4])) != 0;
+}
+
+#endif