/* SPDX-License-Identifier: GPL-2.0 */#ifndef __ASM_GENERIC_CHECKSUM_H#define __ASM_GENERIC_CHECKSUM_H #include <linux/bitops.h> /* * computes the checksum of a memory block at buff, length len, * and adds in "sum" (32-bit) * * returns a 32-bit number suitable for feeding into itself * or csum_tcpudp_magic * * this function must be called with even lengths, except * for the last fragment, which may be odd * * it's best to have buff aligned on a 32-bit boundary */extern __wsum csum_partial(const void *buff, int len, __wsum sum); #ifndef ip_fast_csum/* * This is a version of ip_compute_csum() optimized for IP headers, * which always checksum on 4 octet boundaries. */extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);#endif #ifndef csum_fold/* * Fold a partial checksum */static inline __sum16 csum_fold(__wsum csum){	u32 sum = (__force u32)csum;	return (__force __sum16)((~sum - ror32(sum, 16)) >> 16);}#endif #ifndef csum_tcpudp_nofold/* * computes the checksum of the TCP/UDP pseudo-header * returns a 16-bit checksum, already complemented */extern __wsumcsum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,		   __u8 proto, __wsum sum);#endif #ifndef csum_tcpudp_magicstatic inline __sum16csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len,		  __u8 proto, __wsum sum){	return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));}#endif /* * this routine is used for miscellaneous IP-like checksums, mainly * in icmp.c */extern __sum16 ip_compute_csum(const void *buff, int len); #endif /* __ASM_GENERIC_CHECKSUM_H */