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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
27f85f12 AV |
2 | #ifndef __UM_CHECKSUM_H |
3 | #define __UM_CHECKSUM_H | |
4 | ||
4301785c AV |
5 | #include <linux/string.h> |
6 | #include <linux/in6.h> | |
f8d65d27 | 7 | #include <linux/uaccess.h> |
4301785c AV |
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 | */ | |
21 | extern __wsum csum_partial(const void *buff, int len, __wsum sum); | |
22 | ||
23 | /* | |
24 | * Note: when you get a NULL pointer exception here this means someone | |
25 | * passed in an incorrect kernel address to one of these functions. | |
26 | * | |
27 | * If you use these functions directly please don't forget the | |
28 | * access_ok(). | |
29 | */ | |
30 | ||
31 | static __inline__ | |
32 | __wsum csum_partial_copy_nocheck(const void *src, void *dst, | |
33 | int len, __wsum sum) | |
34 | { | |
35 | memcpy(dst, src, len); | |
36 | return csum_partial(dst, len, sum); | |
37 | } | |
38 | ||
39 | /* | |
40 | * the same as csum_partial, but copies from src while it | |
41 | * checksums, and handles user-space pointer exceptions correctly, when needed. | |
42 | * | |
43 | * here even more important to align src and dst on a 32-bit (or even | |
44 | * better 64-bit) boundary | |
45 | */ | |
46 | ||
47 | static __inline__ | |
48 | __wsum csum_partial_copy_from_user(const void __user *src, void *dst, | |
49 | int len, __wsum sum, int *err_ptr) | |
50 | { | |
51 | if (copy_from_user(dst, src, len)) { | |
52 | *err_ptr = -EFAULT; | |
53 | return (__force __wsum)-1; | |
54 | } | |
55 | ||
56 | return csum_partial(dst, len, sum); | |
57 | } | |
58 | ||
59 | /** | |
60 | * csum_fold - Fold and invert a 32bit checksum. | |
61 | * sum: 32bit unfolded sum | |
62 | * | |
63 | * Fold a 32bit running checksum to 16bit and invert it. This is usually | |
64 | * the last step before putting a checksum into a packet. | |
65 | * Make sure not to mix with 64bit checksums. | |
66 | */ | |
67 | static inline __sum16 csum_fold(__wsum sum) | |
68 | { | |
69 | __asm__( | |
70 | " addl %1,%0\n" | |
71 | " adcl $0xffff,%0" | |
72 | : "=r" (sum) | |
73 | : "r" ((__force u32)sum << 16), | |
74 | "0" ((__force u32)sum & 0xffff0000) | |
75 | ); | |
76 | return (__force __sum16)(~(__force u32)sum >> 16); | |
77 | } | |
78 | ||
79 | /** | |
80 | * csum_tcpup_nofold - Compute an IPv4 pseudo header checksum. | |
81 | * @saddr: source address | |
82 | * @daddr: destination address | |
83 | * @len: length of packet | |
84 | * @proto: ip protocol of packet | |
85 | * @sum: initial sum to be added in (32bit unfolded) | |
86 | * | |
87 | * Returns the pseudo header checksum the input data. Result is | |
88 | * 32bit unfolded. | |
89 | */ | |
90 | static inline __wsum | |
01cfbad7 AD |
91 | csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len, |
92 | __u8 proto, __wsum sum) | |
4301785c AV |
93 | { |
94 | asm(" addl %1, %0\n" | |
95 | " adcl %2, %0\n" | |
96 | " adcl %3, %0\n" | |
97 | " adcl $0, %0\n" | |
98 | : "=r" (sum) | |
99 | : "g" (daddr), "g" (saddr), "g" ((len + proto) << 8), "0" (sum)); | |
100 | return sum; | |
101 | } | |
102 | ||
103 | /* | |
104 | * computes the checksum of the TCP/UDP pseudo-header | |
105 | * returns a 16-bit checksum, already complemented | |
106 | */ | |
107 | static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, | |
01cfbad7 AD |
108 | __u32 len, __u8 proto, |
109 | __wsum sum) | |
4301785c AV |
110 | { |
111 | return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum)); | |
112 | } | |
113 | ||
114 | /** | |
115 | * ip_fast_csum - Compute the IPv4 header checksum efficiently. | |
116 | * iph: ipv4 header | |
117 | * ihl: length of header / 4 | |
118 | */ | |
119 | static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) | |
120 | { | |
121 | unsigned int sum; | |
122 | ||
123 | asm( " movl (%1), %0\n" | |
124 | " subl $4, %2\n" | |
125 | " jbe 2f\n" | |
126 | " addl 4(%1), %0\n" | |
127 | " adcl 8(%1), %0\n" | |
128 | " adcl 12(%1), %0\n" | |
129 | "1: adcl 16(%1), %0\n" | |
130 | " lea 4(%1), %1\n" | |
131 | " decl %2\n" | |
132 | " jne 1b\n" | |
133 | " adcl $0, %0\n" | |
134 | " movl %0, %2\n" | |
135 | " shrl $16, %0\n" | |
136 | " addw %w2, %w0\n" | |
137 | " adcl $0, %0\n" | |
138 | " notl %0\n" | |
139 | "2:" | |
140 | /* Since the input registers which are loaded with iph and ipl | |
141 | are modified, we must also specify them as outputs, or gcc | |
142 | will assume they contain their original values. */ | |
143 | : "=r" (sum), "=r" (iph), "=r" (ihl) | |
144 | : "1" (iph), "2" (ihl) | |
145 | : "memory"); | |
146 | return (__force __sum16)sum; | |
147 | } | |
148 | ||
27f85f12 AV |
149 | #ifdef CONFIG_X86_32 |
150 | # include "checksum_32.h" | |
151 | #else | |
152 | # include "checksum_64.h" | |
153 | #endif | |
154 | ||
155 | #endif |