/* SPDX-License-Identifier: GPL-2.0-or-later *//* * INET		An implementation of the TCP/IP protocol suite for the LINUX *		operating system.  INET is implemented using the  BSD Socket *		interface as the means of communication with the user level. * *		Checksumming functions for IP, TCP, UDP and so on * * Authors:	Jorge Cwik, <jorge@laser.satlink.net> *		Arnt Gulbrandsen, <agulbra@nvg.unit.no> *		Borrows very liberally from tcp.c and ip.c, see those *		files for more names. */ #ifndef _CHECKSUM_H#define _CHECKSUM_H #include <linux/errno.h>#include <asm/types.h>#include <asm/byteorder.h>#include <asm/checksum.h>#if !defined(_HAVE_ARCH_COPY_AND_CSUM_FROM_USER) || !defined(HAVE_CSUM_COPY_USER)#include <linux/uaccess.h>#endif #ifndef _HAVE_ARCH_COPY_AND_CSUM_FROM_USERstatic __always_inline__wsum csum_and_copy_from_user (const void __user *src, void *dst,				      int len){	if (copy_from_user(dst, src, len))		return 0;	return csum_partial(dst, len, ~0U);}#endif #ifndef HAVE_CSUM_COPY_USERstatic __always_inline __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len){	__wsum sum = csum_partial(src, len, ~0U); 	if (copy_to_user(dst, src, len) == 0)		return sum;	return 0;}#endif #ifndef _HAVE_ARCH_CSUM_AND_COPYstatic __always_inline __wsumcsum_partial_copy_nocheck(const void *src, void *dst, int len){	memcpy(dst, src, len);	return csum_partial(dst, len, 0);}#endif #ifndef HAVE_ARCH_CSUM_ADDstatic __always_inline __wsum csum_add(__wsum csum, __wsum addend){	u32 res = (__force u32)csum;	res += (__force u32)addend;	return (__force __wsum)(res + (res < (__force u32)addend));}#endif static __always_inline __wsum csum_sub(__wsum csum, __wsum addend){	return csum_add(csum, ~addend);} static __always_inline __sum16 csum16_add(__sum16 csum, __be16 addend){	u16 res = (__force u16)csum; 	res += (__force u16)addend;	return (__force __sum16)(res + (res < (__force u16)addend));} static __always_inline __sum16 csum16_sub(__sum16 csum, __be16 addend){	return csum16_add(csum, ~addend);} #ifndef HAVE_ARCH_CSUM_SHIFTstatic __always_inline __wsum csum_shift(__wsum sum, int offset){	/* rotate sum to align it with a 16b boundary */	if (offset & 1)		return (__force __wsum)ror32((__force u32)sum, 8);	return sum;}#endif static __always_inline __wsumcsum_block_add(__wsum csum, __wsum csum2, int offset){	return csum_add(csum, csum_shift(csum2, offset));} static __always_inline __wsumcsum_block_sub(__wsum csum, __wsum csum2, int offset){	return csum_block_add(csum, ~csum2, offset);} static __always_inline __wsum csum_unfold(__sum16 n){	return (__force __wsum)n;} #define CSUM_MANGLED_0 ((__force __sum16)0xffff) static __always_inline void csum_replace_by_diff(__sum16 *sum, __wsum diff){	*sum = csum_fold(csum_add(diff, ~csum_unfold(*sum)));} static __always_inline void csum_replace4(__sum16 *sum, __be32 from, __be32 to){	__wsum tmp = csum_sub(~csum_unfold(*sum), (__force __wsum)from); 	*sum = csum_fold(csum_add(tmp, (__force __wsum)to));} /* Implements RFC 1624 (Incremental Internet Checksum) * 3. Discussion states : *     HC' = ~(~HC + ~m + m') *  m : old value of a 16bit field *  m' : new value of a 16bit field */static __always_inline void csum_replace2(__sum16 *sum, __be16 old, __be16 new){	*sum = ~csum16_add(csum16_sub(~(*sum), old), new);} static inline void csum_replace(__wsum *csum, __wsum old, __wsum new){	*csum = csum_add(csum_sub(*csum, old), new);} static inline unsigned short csum_from32to16(unsigned int sum){	sum += (sum >> 16) | (sum << 16);	return (unsigned short)(sum >> 16);} struct sk_buff;void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,			      __be32 from, __be32 to, bool pseudohdr);void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,			       const __be32 *from, const __be32 *to,			       bool pseudohdr);void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb,				     __wsum diff, bool pseudohdr, bool ipv6); static __always_inlinevoid inet_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb,			      __be16 from, __be16 to, bool pseudohdr){	inet_proto_csum_replace4(sum, skb, (__force __be32)from,				 (__force __be32)to, pseudohdr);} static __always_inline __wsum remcsum_adjust(void *ptr, __wsum csum,					     int start, int offset){	__sum16 *psum = (__sum16 *)(ptr + offset);	__wsum delta; 	/* Subtract out checksum up to start */	csum = csum_sub(csum, csum_partial(ptr, start, 0)); 	/* Set derived checksum in packet */	delta = csum_sub((__force __wsum)csum_fold(csum),			 (__force __wsum)*psum);	*psum = csum_fold(csum); 	return delta;} static __always_inline void remcsum_unadjust(__sum16 *psum, __wsum delta){	*psum = csum_fold(csum_sub(delta, (__force __wsum)*psum));} static __always_inline __wsum wsum_negate(__wsum val){	return (__force __wsum)-((__force u32)val);}#endif