[XFRM]: Extract common hashing code into xfrm_hash.[ch]

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 128 insertions, 0 deletions

diff --git a/net/xfrm/xfrm_hash.h b/net/xfrm/xfrm_hash.h
new file mode 100644
index 000000000000..d3abb0b7dc62
--- /dev/null
+++ b/net/xfrm/xfrm_hash.h
@@ -0,0 +1,128 @@
+#ifndef _XFRM_HASH_H
+#define _XFRM_HASH_H
+
+#include <linux/xfrm.h>
+#include <linux/socket.h>
+
+static inline unsigned int __xfrm4_addr_hash(xfrm_address_t *addr)
+{
+        return ntohl(addr->a4);
+}
+
+static inline unsigned int __xfrm6_addr_hash(xfrm_address_t *addr)
+{
+        return ntohl(addr->a6[2] ^ addr->a6[3]);
+}
+
+static inline unsigned int __xfrm4_daddr_saddr_hash(xfrm_address_t *daddr, xfrm_address_t *saddr)
+{
+        return ntohl(daddr->a4 ^ saddr->a4);
+}
+
+static inline unsigned int __xfrm6_daddr_saddr_hash(xfrm_address_t *daddr, xfrm_address_t *saddr)
+{
+        return ntohl(daddr->a6[2] ^ daddr->a6[3] ^
+                     saddr->a6[2] ^ saddr->a6[3]);
+}
+
+static inline unsigned int __xfrm_dst_hash(xfrm_address_t *daddr, xfrm_address_t *saddr,
+                                           u32 reqid, unsigned short family,
+                                           unsigned int hmask)
+{
+        unsigned int h = family ^ reqid;
+        switch (family) {
+        case AF_INET:
+                h ^= __xfrm4_daddr_saddr_hash(daddr, saddr);
+                break;
+        case AF_INET6:
+                h ^= __xfrm6_daddr_saddr_hash(daddr, saddr);
+                break;
+        }
+        return (h ^ (h >> 16)) & hmask;
+}
+
+static inline unsigned __xfrm_src_hash(xfrm_address_t *saddr,
+                                       unsigned short family,
+                                       unsigned int hmask)
+{
+        unsigned int h = family;
+        switch (family) {
+        case AF_INET:
+                h ^= __xfrm4_addr_hash(saddr);
+                break;
+        case AF_INET6:
+                h ^= __xfrm6_addr_hash(saddr);
+                break;
+        };
+        return (h ^ (h >> 16)) & hmask;
+}
+
+static inline unsigned int
+__xfrm_spi_hash(xfrm_address_t *daddr, u32 spi, u8 proto, unsigned short family,
+                unsigned int hmask)
+{
+        unsigned int h = spi ^ proto;
+        switch (family) {
+        case AF_INET:
+                h ^= __xfrm4_addr_hash(daddr);
+                break;
+        case AF_INET6:
+                h ^= __xfrm6_addr_hash(daddr);
+                break;
+        }
+        return (h ^ (h >> 10) ^ (h >> 20)) & hmask;
+}
+
+static inline unsigned int __idx_hash(u32 index, unsigned int hmask)
+{
+        return (index ^ (index >> 8)) & hmask;
+}
+
+static inline unsigned int __sel_hash(struct xfrm_selector *sel, unsigned short family, unsigned int hmask)
+{
+        xfrm_address_t *daddr = &sel->daddr;
+        xfrm_address_t *saddr = &sel->saddr;
+        unsigned int h = 0;
+
+        switch (family) {
+        case AF_INET:
+                if (sel->prefixlen_d != 32 ||
+                    sel->prefixlen_s != 32)
+                        return hmask + 1;
+
+                h = __xfrm4_daddr_saddr_hash(daddr, saddr);
+                break;
+
+        case AF_INET6:
+                if (sel->prefixlen_d != 128 ||
+                    sel->prefixlen_s != 128)
+                        return hmask + 1;
+
+                h = __xfrm6_daddr_saddr_hash(daddr, saddr);
+                break;
+        };
+        h ^= (h >> 16);
+        return h & hmask;
+}
+
+static inline unsigned int __addr_hash(xfrm_address_t *daddr, xfrm_address_t *saddr, unsigned short family, unsigned int hmask)
+{
+        unsigned int h = 0;
+
+        switch (family) {
+        case AF_INET:
+                h = __xfrm4_daddr_saddr_hash(daddr, saddr);
+                break;
+
+        case AF_INET6:
+                h = __xfrm6_daddr_saddr_hash(daddr, saddr);
+                break;
+        };
+        h ^= (h >> 16);
+        return h & hmask;
+}
+
+extern struct hlist_head *xfrm_hash_alloc(unsigned int sz);
+extern void xfrm_hash_free(struct hlist_head *n, unsigned int sz);
+
+#endif /* _XFRM_HASH_H */