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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __UM_CHECKSUM_H
3#define __UM_CHECKSUM_H
4
5#include <linux/string.h>
6#include <linux/in6.h>
7#include <linux/uaccess.h>
8
9/*
10 * computes the checksum of a memory block at buff, length len,
11 * and adds in "sum" (32-bit)
12 *
13 * returns a 32-bit number suitable for feeding into itself
14 * or csum_tcpudp_magic
15 *
16 * this function must be called with even lengths, except
17 * for the last fragment, which may be odd
18 *
19 * it's best to have buff aligned on a 32-bit boundary
20 */
21extern __wsum csum_partial(const void *buff, int len, __wsum sum);
22
23/**
24 * csum_fold - Fold and invert a 32bit checksum.
25 * sum: 32bit unfolded sum
26 *
27 * Fold a 32bit running checksum to 16bit and invert it. This is usually
28 * the last step before putting a checksum into a packet.
29 * Make sure not to mix with 64bit checksums.
30 */
31static inline __sum16 csum_fold(__wsum sum)
32{
33 __asm__(
34 " addl %1,%0\n"
35 " adcl $0xffff,%0"
36 : "=r" (sum)
37 : "r" ((__force u32)sum << 16),
38 "0" ((__force u32)sum & 0xffff0000)
39 );
40 return (__force __sum16)(~(__force u32)sum >> 16);
41}
42
43/**
44 * csum_tcpup_nofold - Compute an IPv4 pseudo header checksum.
45 * @saddr: source address
46 * @daddr: destination address
47 * @len: length of packet
48 * @proto: ip protocol of packet
49 * @sum: initial sum to be added in (32bit unfolded)
50 *
51 * Returns the pseudo header checksum the input data. Result is
52 * 32bit unfolded.
53 */
54static inline __wsum
55csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
56 __u8 proto, __wsum sum)
57{
58 asm(" addl %1, %0\n"
59 " adcl %2, %0\n"
60 " adcl %3, %0\n"
61 " adcl $0, %0\n"
62 : "=r" (sum)
63 : "g" (daddr), "g" (saddr), "g" ((len + proto) << 8), "0" (sum));
64 return sum;
65}
66
67/*
68 * computes the checksum of the TCP/UDP pseudo-header
69 * returns a 16-bit checksum, already complemented
70 */
71static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
72 __u32 len, __u8 proto,
73 __wsum sum)
74{
75 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
76}
77
78/**
79 * ip_fast_csum - Compute the IPv4 header checksum efficiently.
80 * iph: ipv4 header
81 * ihl: length of header / 4
82 */
83static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
84{
85 unsigned int sum;
86
87 asm( " movl (%1), %0\n"
88 " subl $4, %2\n"
89 " jbe 2f\n"
90 " addl 4(%1), %0\n"
91 " adcl 8(%1), %0\n"
92 " adcl 12(%1), %0\n"
93 "1: adcl 16(%1), %0\n"
94 " lea 4(%1), %1\n"
95 " decl %2\n"
96 " jne 1b\n"
97 " adcl $0, %0\n"
98 " movl %0, %2\n"
99 " shrl $16, %0\n"
100 " addw %w2, %w0\n"
101 " adcl $0, %0\n"
102 " notl %0\n"
103 "2:"
104 /* Since the input registers which are loaded with iph and ipl
105 are modified, we must also specify them as outputs, or gcc
106 will assume they contain their original values. */
107 : "=r" (sum), "=r" (iph), "=r" (ihl)
108 : "1" (iph), "2" (ihl)
109 : "memory");
110 return (__force __sum16)sum;
111}
112
113#ifdef CONFIG_X86_32
114# include "checksum_32.h"
115#else
116# include "checksum_64.h"
117#endif
118
119#endif
1#ifndef __UM_CHECKSUM_H
2#define __UM_CHECKSUM_H
3
4#include <linux/string.h>
5#include <linux/in6.h>
6#include <linux/uaccess.h>
7
8/*
9 * computes the checksum of a memory block at buff, length len,
10 * and adds in "sum" (32-bit)
11 *
12 * returns a 32-bit number suitable for feeding into itself
13 * or csum_tcpudp_magic
14 *
15 * this function must be called with even lengths, except
16 * for the last fragment, which may be odd
17 *
18 * it's best to have buff aligned on a 32-bit boundary
19 */
20extern __wsum csum_partial(const void *buff, int len, __wsum sum);
21
22/*
23 * Note: when you get a NULL pointer exception here this means someone
24 * passed in an incorrect kernel address to one of these functions.
25 *
26 * If you use these functions directly please don't forget the
27 * access_ok().
28 */
29
30static __inline__
31__wsum csum_partial_copy_nocheck(const void *src, void *dst,
32 int len, __wsum sum)
33{
34 memcpy(dst, src, len);
35 return csum_partial(dst, len, sum);
36}
37
38/*
39 * the same as csum_partial, but copies from src while it
40 * checksums, and handles user-space pointer exceptions correctly, when needed.
41 *
42 * here even more important to align src and dst on a 32-bit (or even
43 * better 64-bit) boundary
44 */
45
46static __inline__
47__wsum csum_partial_copy_from_user(const void __user *src, void *dst,
48 int len, __wsum sum, int *err_ptr)
49{
50 if (copy_from_user(dst, src, len)) {
51 *err_ptr = -EFAULT;
52 return (__force __wsum)-1;
53 }
54
55 return csum_partial(dst, len, sum);
56}
57
58/**
59 * csum_fold - Fold and invert a 32bit checksum.
60 * sum: 32bit unfolded sum
61 *
62 * Fold a 32bit running checksum to 16bit and invert it. This is usually
63 * the last step before putting a checksum into a packet.
64 * Make sure not to mix with 64bit checksums.
65 */
66static inline __sum16 csum_fold(__wsum sum)
67{
68 __asm__(
69 " addl %1,%0\n"
70 " adcl $0xffff,%0"
71 : "=r" (sum)
72 : "r" ((__force u32)sum << 16),
73 "0" ((__force u32)sum & 0xffff0000)
74 );
75 return (__force __sum16)(~(__force u32)sum >> 16);
76}
77
78/**
79 * csum_tcpup_nofold - Compute an IPv4 pseudo header checksum.
80 * @saddr: source address
81 * @daddr: destination address
82 * @len: length of packet
83 * @proto: ip protocol of packet
84 * @sum: initial sum to be added in (32bit unfolded)
85 *
86 * Returns the pseudo header checksum the input data. Result is
87 * 32bit unfolded.
88 */
89static inline __wsum
90csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
91 __u8 proto, __wsum sum)
92{
93 asm(" addl %1, %0\n"
94 " adcl %2, %0\n"
95 " adcl %3, %0\n"
96 " adcl $0, %0\n"
97 : "=r" (sum)
98 : "g" (daddr), "g" (saddr), "g" ((len + proto) << 8), "0" (sum));
99 return sum;
100}
101
102/*
103 * computes the checksum of the TCP/UDP pseudo-header
104 * returns a 16-bit checksum, already complemented
105 */
106static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
107 __u32 len, __u8 proto,
108 __wsum sum)
109{
110 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
111}
112
113/**
114 * ip_fast_csum - Compute the IPv4 header checksum efficiently.
115 * iph: ipv4 header
116 * ihl: length of header / 4
117 */
118static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
119{
120 unsigned int sum;
121
122 asm( " movl (%1), %0\n"
123 " subl $4, %2\n"
124 " jbe 2f\n"
125 " addl 4(%1), %0\n"
126 " adcl 8(%1), %0\n"
127 " adcl 12(%1), %0\n"
128 "1: adcl 16(%1), %0\n"
129 " lea 4(%1), %1\n"
130 " decl %2\n"
131 " jne 1b\n"
132 " adcl $0, %0\n"
133 " movl %0, %2\n"
134 " shrl $16, %0\n"
135 " addw %w2, %w0\n"
136 " adcl $0, %0\n"
137 " notl %0\n"
138 "2:"
139 /* Since the input registers which are loaded with iph and ipl
140 are modified, we must also specify them as outputs, or gcc
141 will assume they contain their original values. */
142 : "=r" (sum), "=r" (iph), "=r" (ihl)
143 : "1" (iph), "2" (ihl)
144 : "memory");
145 return (__force __sum16)sum;
146}
147
148#ifdef CONFIG_X86_32
149# include "checksum_32.h"
150#else
151# include "checksum_64.h"
152#endif
153
154#endif