netfilter: factorize ifname_compare()
We use same not trivial helper function in four places. We can factorize it.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h
index e8e08d0..72918b7 100644
--- a/include/linux/netfilter/x_tables.h
+++ b/include/linux/netfilter/x_tables.h
@@ -435,6 +435,29 @@
extern void xt_table_entry_swap_rcu(struct xt_table_info *old,
struct xt_table_info *new);
+/*
+ * This helper is performance critical and must be inlined
+ */
+static inline unsigned long ifname_compare_aligned(const char *_a,
+ const char *_b,
+ const char *_mask)
+{
+ const unsigned long *a = (const unsigned long *)_a;
+ const unsigned long *b = (const unsigned long *)_b;
+ const unsigned long *mask = (const unsigned long *)_mask;
+ unsigned long ret;
+
+ ret = (a[0] ^ b[0]) & mask[0];
+ if (IFNAMSIZ > sizeof(unsigned long))
+ ret |= (a[1] ^ b[1]) & mask[1];
+ if (IFNAMSIZ > 2 * sizeof(unsigned long))
+ ret |= (a[2] ^ b[2]) & mask[2];
+ if (IFNAMSIZ > 3 * sizeof(unsigned long))
+ ret |= (a[3] ^ b[3]) & mask[3];
+ BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long));
+ return ret;
+}
+
#ifdef CONFIG_COMPAT
#include <net/compat.h>