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>

1 files changed, 23 insertions, 0 deletions

diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h
index e8e08d03675..72918b7cbe8 100644
--- a/include/linux/netfilter/x_tables.h
+++ b/include/linux/netfilter/x_tables.h
@@ -435,6 +435,29 @@ extern void xt_free_table_info(struct xt_table_info *info);
 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>