1/* SPDX-License-Identifier: GPL-2.0-or-later */ 2/* 3 * INET An implementation of the TCP/IP protocol suite for the LINUX 4 * operating system. INET is implemented using the BSD Socket 5 * interface as the means of communication with the user level. 6 * 7 * Checksumming functions for IP, TCP, UDP and so on 8 * 9 * Authors: Jorge Cwik, <jorge@laser.satlink.net> 10 * Arnt Gulbrandsen, <agulbra@nvg.unit.no> 11 * Borrows very liberally from tcp.c and ip.c, see those 12 * files for more names. 13 */ 14 15#ifndef _CHECKSUM_H 16#define _CHECKSUM_H 17 18#include <linux/errno.h> 19#include <asm/types.h> 20#include <asm/byteorder.h> 21#include <linux/uaccess.h> 22#include <asm/checksum.h> 23 24#ifndef _HAVE_ARCH_COPY_AND_CSUM_FROM_USER 25static __always_inline 26__wsum csum_and_copy_from_user (const void __user *src, void *dst, 27 int len) 28{ 29 if (copy_from_user(dst, src, len)) 30 return 0; 31 return csum_partial(dst, len, ~0U); 32} 33#endif 34 35#ifndef HAVE_CSUM_COPY_USER 36static __always_inline __wsum csum_and_copy_to_user 37(const void *src, void __user *dst, int len) 38{ 39 __wsum sum = csum_partial(src, len, ~0U); 40 41 if (copy_to_user(dst, src, len) == 0) 42 return sum; 43 return 0; 44} 45#endif 46 47#ifndef _HAVE_ARCH_CSUM_AND_COPY 48static __always_inline __wsum 49csum_partial_copy_nocheck(const void *src, void *dst, int len) 50{ 51 memcpy(dst, src, len); 52 return csum_partial(dst, len, 0); 53} 54#endif 55 56#ifndef HAVE_ARCH_CSUM_ADD 57static __always_inline __wsum csum_add(__wsum csum, __wsum addend) 58{ 59 u32 res = (__force u32)csum; 60 res += (__force u32)addend; 61 return (__force __wsum)(res + (res < (__force u32)addend)); 62} 63#endif 64 65static __always_inline __wsum csum_sub(__wsum csum, __wsum addend) 66{ 67 return csum_add(csum, ~addend); 68} 69 70static __always_inline __sum16 csum16_add(__sum16 csum, __be16 addend) 71{ 72 u16 res = (__force u16)csum; 73 74 res += (__force u16)addend; 75 return (__force __sum16)(res + (res < (__force u16)addend)); 76} 77 78static __always_inline __sum16 csum16_sub(__sum16 csum, __be16 addend) 79{ 80 return csum16_add(csum, ~addend); 81} 82 83static __always_inline __wsum 84csum_block_add(__wsum csum, __wsum csum2, int offset) 85{ 86 u32 sum = (__force u32)csum2; 87 88 /* rotate sum to align it with a 16b boundary */ 89 if (offset & 1) 90 sum = ror32(sum, 8); 91 92 return csum_add(csum, (__force __wsum)sum); 93} 94 95static __always_inline __wsum 96csum_block_add_ext(__wsum csum, __wsum csum2, int offset, int len) 97{ 98 return csum_block_add(csum, csum2, offset); 99} 100 101static __always_inline __wsum 102csum_block_sub(__wsum csum, __wsum csum2, int offset) 103{ 104 return csum_block_add(csum, ~csum2, offset); 105} 106 107static __always_inline __wsum csum_unfold(__sum16 n) 108{ 109 return (__force __wsum)n; 110} 111 112static __always_inline 113__wsum csum_partial_ext(const void *buff, int len, __wsum sum) 114{ 115 return csum_partial(buff, len, sum); 116} 117 118#define CSUM_MANGLED_0 ((__force __sum16)0xffff) 119 120static __always_inline void csum_replace_by_diff(__sum16 *sum, __wsum diff) 121{ 122 *sum = csum_fold(csum_add(diff, ~csum_unfold(*sum))); 123} 124 125static __always_inline void csum_replace4(__sum16 *sum, __be32 from, __be32 to) 126{ 127 __wsum tmp = csum_sub(~csum_unfold(*sum), (__force __wsum)from); 128 129 *sum = csum_fold(csum_add(tmp, (__force __wsum)to)); 130} 131 132/* Implements RFC 1624 (Incremental Internet Checksum) 133 * 3. Discussion states : 134 * HC' = ~(~HC + ~m + m') 135 * m : old value of a 16bit field 136 * m' : new value of a 16bit field 137 */ 138static __always_inline void csum_replace2(__sum16 *sum, __be16 old, __be16 new) 139{ 140 *sum = ~csum16_add(csum16_sub(~(*sum), old), new); 141} 142 143static inline void csum_replace(__wsum *csum, __wsum old, __wsum new) 144{ 145 *csum = csum_add(csum_sub(*csum, old), new); 146} 147 148struct sk_buff; 149void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb, 150 __be32 from, __be32 to, bool pseudohdr); 151void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb, 152 const __be32 *from, const __be32 *to, 153 bool pseudohdr); 154void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb, 155 __wsum diff, bool pseudohdr); 156 157static __always_inline 158void inet_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb, 159 __be16 from, __be16 to, bool pseudohdr) 160{ 161 inet_proto_csum_replace4(sum, skb, (__force __be32)from, 162 (__force __be32)to, pseudohdr); 163} 164 165static __always_inline __wsum remcsum_adjust(void *ptr, __wsum csum, 166 int start, int offset) 167{ 168 __sum16 *psum = (__sum16 *)(ptr + offset); 169 __wsum delta; 170 171 /* Subtract out checksum up to start */ 172 csum = csum_sub(csum, csum_partial(ptr, start, 0)); 173 174 /* Set derived checksum in packet */ 175 delta = csum_sub((__force __wsum)csum_fold(csum), 176 (__force __wsum)*psum); 177 *psum = csum_fold(csum); 178 179 return delta; 180} 181 182static __always_inline void remcsum_unadjust(__sum16 *psum, __wsum delta) 183{ 184 *psum = csum_fold(csum_sub(delta, (__force __wsum)*psum)); 185} 186 187#endif 188