/* SPDX-License-Identifier: GPL-2.0 */

  #ifndef _XFRM_HASH_H
  #define _XFRM_HASH_H
  
  #include <linux/xfrm.h>
  #include <linux/socket.h>

  #include <linux/jhash.h>

  static inline unsigned int __xfrm4_addr_hash(const xfrm_address_t *addr)

  {
  	return ntohl(addr->a4);
  }

  static inline unsigned int __xfrm6_addr_hash(const xfrm_address_t *addr)

  {

  	return jhash2((__force u32 *)addr->a6, 4, 0);

  }

  static inline unsigned int __xfrm4_daddr_saddr_hash(const xfrm_address_t *daddr,
  						    const xfrm_address_t *saddr)

  {

  	u32 sum = (__force u32)daddr->a4 + (__force u32)saddr->a4;
  	return ntohl((__force __be32)sum);

  }

  static inline unsigned int __xfrm6_daddr_saddr_hash(const xfrm_address_t *daddr,
  						    const xfrm_address_t *saddr)

  {

  	return __xfrm6_addr_hash(daddr) ^ __xfrm6_addr_hash(saddr);

  }

  static inline u32 __bits2mask32(__u8 bits)
  {
  	u32 mask32 = 0xffffffff;
  
  	if (bits == 0)
  		mask32 = 0;
  	else if (bits < 32)
  		mask32 <<= (32 - bits);
  
  	return mask32;
  }
  
  static inline unsigned int __xfrm4_dpref_spref_hash(const xfrm_address_t *daddr,
  						    const xfrm_address_t *saddr,
  						    __u8 dbits,
  						    __u8 sbits)
  {
  	return jhash_2words(ntohl(daddr->a4) & __bits2mask32(dbits),
  			    ntohl(saddr->a4) & __bits2mask32(sbits),
  			    0);
  }
  
  static inline unsigned int __xfrm6_pref_hash(const xfrm_address_t *addr,
  					     __u8 prefixlen)
  {

  	unsigned int pdw;
  	unsigned int pbi;

  	u32 initval = 0;
  
  	pdw = prefixlen >> 5;     /* num of whole u32 in prefix */
  	pbi = prefixlen &  0x1f;  /* num of bits in incomplete u32 in prefix */
  
  	if (pbi) {
  		__be32 mask;
  
  		mask = htonl((0xffffffff) << (32 - pbi));
  
  		initval = (__force u32)(addr->a6[pdw] & mask);
  	}
  
  	return jhash2((__force u32 *)addr->a6, pdw, initval);
  }
  
  static inline unsigned int __xfrm6_dpref_spref_hash(const xfrm_address_t *daddr,
  						    const xfrm_address_t *saddr,
  						    __u8 dbits,
  						    __u8 sbits)
  {
  	return __xfrm6_pref_hash(daddr, dbits) ^
  	       __xfrm6_pref_hash(saddr, sbits);
  }

  static inline unsigned int __xfrm_dst_hash(const xfrm_address_t *daddr,
  					   const 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 int __xfrm_src_hash(const xfrm_address_t *daddr,
  					   const xfrm_address_t *saddr,
  					   unsigned short family,
  					   unsigned int hmask)

  {
  	unsigned int h = family;
  	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 int

  __xfrm_spi_hash(const xfrm_address_t *daddr, __be32 spi, u8 proto,
  		unsigned short family, unsigned int hmask)

  {

  	unsigned int h = (__force u32)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(const struct xfrm_selector *sel,

  				      unsigned short family, unsigned int hmask,
  				      u8 dbits, u8 sbits)

  {

  	const xfrm_address_t *daddr = &sel->daddr;
  	const xfrm_address_t *saddr = &sel->saddr;

  	unsigned int h = 0;
  
  	switch (family) {
  	case AF_INET:

  		if (sel->prefixlen_d < dbits ||
  		    sel->prefixlen_s < sbits)

  			return hmask + 1;

  		h = __xfrm4_dpref_spref_hash(daddr, saddr, dbits, sbits);

  		break;
  
  	case AF_INET6:

  		if (sel->prefixlen_d < dbits ||
  		    sel->prefixlen_s < sbits)

  			return hmask + 1;

  		h = __xfrm6_dpref_spref_hash(daddr, saddr, dbits, sbits);

  		break;

  	}

  	h ^= (h >> 16);
  	return h & hmask;
  }

  static inline unsigned int __addr_hash(const xfrm_address_t *daddr,
  				       const xfrm_address_t *saddr,

  				       unsigned short family,
  				       unsigned int hmask,
  				       u8 dbits, u8 sbits)

  {
  	unsigned int h = 0;
  
  	switch (family) {
  	case AF_INET:

  		h = __xfrm4_dpref_spref_hash(daddr, saddr, dbits, sbits);

  		break;
  
  	case AF_INET6:

  		h = __xfrm6_dpref_spref_hash(daddr, saddr, dbits, sbits);

  		break;

  	}

  	h ^= (h >> 16);
  	return h & hmask;
  }

  struct hlist_head *xfrm_hash_alloc(unsigned int sz);
  void xfrm_hash_free(struct hlist_head *n, unsigned int sz);

  
  #endif /* _XFRM_HASH_H */