1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_X86_CHECKSUM_64_H 3 #define _ASM_X86_CHECKSUM_64_H 4 5 /* 6 * Checksums for x86-64 7 * Copyright 2002 by Andi Kleen, SuSE Labs 8 * with some code from asm-x86/checksum.h 9 */ 10 11 #include <linux/compiler.h> 12 #include <linux/uaccess.h> 13 #include <asm/byteorder.h> 14 15 /** 16 * csum_fold - Fold and invert a 32bit checksum. 17 * sum: 32bit unfolded sum 18 * 19 * Fold a 32bit running checksum to 16bit and invert it. This is usually 20 * the last step before putting a checksum into a packet. 21 * Make sure not to mix with 64bit checksums. 22 */ 23 static inline __sum16 csum_fold(__wsum sum) 24 { 25 asm(" addl %1,%0\n" 26 " adcl $0xffff,%0" 27 : "=r" (sum) 28 : "r" ((__force u32)sum << 16), 29 "0" ((__force u32)sum & 0xffff0000)); 30 return (__force __sum16)(~(__force u32)sum >> 16); 31 } 32 33 /* 34 * This is a version of ip_compute_csum() optimized for IP headers, 35 * which always checksum on 4 octet boundaries. 36 * 37 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by 38 * Arnt Gulbrandsen. 39 */ 40 41 /** 42 * ip_fast_csum - Compute the IPv4 header checksum efficiently. 43 * iph: ipv4 header 44 * ihl: length of header / 4 45 */ 46 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) 47 { 48 unsigned int sum; 49 50 asm(" movl (%1), %0\n" 51 " subl $4, %2\n" 52 " jbe 2f\n" 53 " addl 4(%1), %0\n" 54 " adcl 8(%1), %0\n" 55 " adcl 12(%1), %0\n" 56 "1: adcl 16(%1), %0\n" 57 " lea 4(%1), %1\n" 58 " decl %2\n" 59 " jne 1b\n" 60 " adcl $0, %0\n" 61 " movl %0, %2\n" 62 " shrl $16, %0\n" 63 " addw %w2, %w0\n" 64 " adcl $0, %0\n" 65 " notl %0\n" 66 "2:" 67 /* Since the input registers which are loaded with iph and ihl 68 are modified, we must also specify them as outputs, or gcc 69 will assume they contain their original values. */ 70 : "=r" (sum), "=r" (iph), "=r" (ihl) 71 : "1" (iph), "2" (ihl) 72 : "memory"); 73 return (__force __sum16)sum; 74 } 75 76 /** 77 * csum_tcpup_nofold - Compute an IPv4 pseudo header checksum. 78 * @saddr: source address 79 * @daddr: destination address 80 * @len: length of packet 81 * @proto: ip protocol of packet 82 * @sum: initial sum to be added in (32bit unfolded) 83 * 84 * Returns the pseudo header checksum the input data. Result is 85 * 32bit unfolded. 86 */ 87 static inline __wsum 88 csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len, 89 __u8 proto, __wsum sum) 90 { 91 asm(" addl %1, %0\n" 92 " adcl %2, %0\n" 93 " adcl %3, %0\n" 94 " adcl $0, %0\n" 95 : "=r" (sum) 96 : "g" (daddr), "g" (saddr), 97 "g" ((len + proto)<<8), "0" (sum)); 98 return sum; 99 } 100 101 102 /** 103 * csum_tcpup_magic - Compute an IPv4 pseudo header checksum. 104 * @saddr: source address 105 * @daddr: destination address 106 * @len: length of packet 107 * @proto: ip protocol of packet 108 * @sum: initial sum to be added in (32bit unfolded) 109 * 110 * Returns the 16bit pseudo header checksum the input data already 111 * complemented and ready to be filled in. 112 */ 113 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, 114 __u32 len, __u8 proto, 115 __wsum sum) 116 { 117 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); 118 } 119 120 /** 121 * csum_partial - Compute an internet checksum. 122 * @buff: buffer to be checksummed 123 * @len: length of buffer. 124 * @sum: initial sum to be added in (32bit unfolded) 125 * 126 * Returns the 32bit unfolded internet checksum of the buffer. 127 * Before filling it in it needs to be csum_fold()'ed. 128 * buff should be aligned to a 64bit boundary if possible. 129 */ 130 extern __wsum csum_partial(const void *buff, int len, __wsum sum); 131 132 /* Do not call this directly. Use the wrappers below */ 133 extern __visible __wsum csum_partial_copy_generic(const void *src, const void *dst, 134 int len, __wsum sum, 135 int *src_err_ptr, int *dst_err_ptr); 136 137 138 extern __wsum csum_and_copy_from_user(const void __user *src, void *dst, 139 int len, __wsum isum, int *errp); 140 extern __wsum csum_and_copy_to_user(const void *src, void __user *dst, 141 int len, __wsum isum, int *errp); 142 extern __wsum csum_partial_copy_nocheck(const void *src, void *dst, 143 int len, __wsum sum); 144 145 /** 146 * ip_compute_csum - Compute an 16bit IP checksum. 147 * @buff: buffer address. 148 * @len: length of buffer. 149 * 150 * Returns the 16bit folded/inverted checksum of the passed buffer. 151 * Ready to fill in. 152 */ 153 extern __sum16 ip_compute_csum(const void *buff, int len); 154 155 /** 156 * csum_ipv6_magic - Compute checksum of an IPv6 pseudo header. 157 * @saddr: source address 158 * @daddr: destination address 159 * @len: length of packet 160 * @proto: protocol of packet 161 * @sum: initial sum (32bit unfolded) to be added in 162 * 163 * Computes an IPv6 pseudo header checksum. This sum is added the checksum 164 * into UDP/TCP packets and contains some link layer information. 165 * Returns the unfolded 32bit checksum. 166 */ 167 168 struct in6_addr; 169 170 #define _HAVE_ARCH_IPV6_CSUM 1 171 extern __sum16 172 csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr, 173 __u32 len, __u8 proto, __wsum sum); 174 175 static inline unsigned add32_with_carry(unsigned a, unsigned b) 176 { 177 asm("addl %2,%0\n\t" 178 "adcl $0,%0" 179 : "=r" (a) 180 : "0" (a), "rm" (b)); 181 return a; 182 } 183 184 #define HAVE_ARCH_CSUM_ADD 185 static inline __wsum csum_add(__wsum csum, __wsum addend) 186 { 187 return (__force __wsum)add32_with_carry((__force unsigned)csum, 188 (__force unsigned)addend); 189 } 190 191 #endif /* _ASM_X86_CHECKSUM_64_H */ 192