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