1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_X86_CHECKSUM_32_H
3 #define _ASM_X86_CHECKSUM_32_H
4
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 */
20 asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum);
21
22 /*
23 * the same as csum_partial, but copies from src while it
24 * checksums, and handles user-space pointer exceptions correctly, when needed.
25 *
26 * here even more important to align src and dst on a 32-bit (or even
27 * better 64-bit) boundary
28 */
29
30 asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
31 int len, __wsum sum,
32 int *src_err_ptr, int *dst_err_ptr);
33
34 /*
35 * Note: when you get a NULL pointer exception here this means someone
36 * passed in an incorrect kernel address to one of these functions.
37 *
38 * If you use these functions directly please don't forget the
39 * access_ok().
40 */
csum_partial_copy_nocheck(const void * src,void * dst,int len,__wsum sum)41 static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst,
42 int len, __wsum sum)
43 {
44 return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
45 }
46
csum_partial_copy_from_user(const void __user * src,void * dst,int len,__wsum sum,int * err_ptr)47 static inline __wsum csum_partial_copy_from_user(const void __user *src,
48 void *dst,
49 int len, __wsum sum,
50 int *err_ptr)
51 {
52 __wsum ret;
53
54 might_sleep();
55 stac();
56 ret = csum_partial_copy_generic((__force void *)src, dst,
57 len, sum, err_ptr, NULL);
58 clac();
59
60 return ret;
61 }
62
63 /*
64 * This is a version of ip_compute_csum() optimized for IP headers,
65 * which always checksum on 4 octet boundaries.
66 *
67 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
68 * Arnt Gulbrandsen.
69 */
ip_fast_csum(const void * iph,unsigned int ihl)70 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
71 {
72 unsigned int sum;
73
74 asm volatile("movl (%1), %0 ;\n"
75 "subl $4, %2 ;\n"
76 "jbe 2f ;\n"
77 "addl 4(%1), %0 ;\n"
78 "adcl 8(%1), %0 ;\n"
79 "adcl 12(%1), %0;\n"
80 "1: adcl 16(%1), %0 ;\n"
81 "lea 4(%1), %1 ;\n"
82 "decl %2 ;\n"
83 "jne 1b ;\n"
84 "adcl $0, %0 ;\n"
85 "movl %0, %2 ;\n"
86 "shrl $16, %0 ;\n"
87 "addw %w2, %w0 ;\n"
88 "adcl $0, %0 ;\n"
89 "notl %0 ;\n"
90 "2: ;\n"
91 /* Since the input registers which are loaded with iph and ihl
92 are modified, we must also specify them as outputs, or gcc
93 will assume they contain their original values. */
94 : "=r" (sum), "=r" (iph), "=r" (ihl)
95 : "1" (iph), "2" (ihl)
96 : "memory");
97 return (__force __sum16)sum;
98 }
99
100 /*
101 * Fold a partial checksum
102 */
103
csum_fold(__wsum sum)104 static inline __sum16 csum_fold(__wsum sum)
105 {
106 asm("addl %1, %0 ;\n"
107 "adcl $0xffff, %0 ;\n"
108 : "=r" (sum)
109 : "r" ((__force u32)sum << 16),
110 "0" ((__force u32)sum & 0xffff0000));
111 return (__force __sum16)(~(__force u32)sum >> 16);
112 }
113
csum_tcpudp_nofold(__be32 saddr,__be32 daddr,__u32 len,__u8 proto,__wsum sum)114 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
115 __u32 len, __u8 proto,
116 __wsum sum)
117 {
118 asm("addl %1, %0 ;\n"
119 "adcl %2, %0 ;\n"
120 "adcl %3, %0 ;\n"
121 "adcl $0, %0 ;\n"
122 : "=r" (sum)
123 : "g" (daddr), "g"(saddr),
124 "g" ((len + proto) << 8), "0" (sum));
125 return sum;
126 }
127
128 /*
129 * computes the checksum of the TCP/UDP pseudo-header
130 * returns a 16-bit checksum, already complemented
131 */
csum_tcpudp_magic(__be32 saddr,__be32 daddr,__u32 len,__u8 proto,__wsum sum)132 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
133 __u32 len, __u8 proto,
134 __wsum sum)
135 {
136 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
137 }
138
139 /*
140 * this routine is used for miscellaneous IP-like checksums, mainly
141 * in icmp.c
142 */
143
ip_compute_csum(const void * buff,int len)144 static inline __sum16 ip_compute_csum(const void *buff, int len)
145 {
146 return csum_fold(csum_partial(buff, len, 0));
147 }
148
149 #define _HAVE_ARCH_IPV6_CSUM
csum_ipv6_magic(const struct in6_addr * saddr,const struct in6_addr * daddr,__u32 len,__u8 proto,__wsum sum)150 static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
151 const struct in6_addr *daddr,
152 __u32 len, __u8 proto, __wsum sum)
153 {
154 asm("addl 0(%1), %0 ;\n"
155 "adcl 4(%1), %0 ;\n"
156 "adcl 8(%1), %0 ;\n"
157 "adcl 12(%1), %0 ;\n"
158 "adcl 0(%2), %0 ;\n"
159 "adcl 4(%2), %0 ;\n"
160 "adcl 8(%2), %0 ;\n"
161 "adcl 12(%2), %0 ;\n"
162 "adcl %3, %0 ;\n"
163 "adcl %4, %0 ;\n"
164 "adcl $0, %0 ;\n"
165 : "=&r" (sum)
166 : "r" (saddr), "r" (daddr),
167 "r" (htonl(len)), "r" (htonl(proto)), "0" (sum)
168 : "memory");
169
170 return csum_fold(sum);
171 }
172
173 /*
174 * Copy and checksum to user
175 */
176 #define HAVE_CSUM_COPY_USER
csum_and_copy_to_user(const void * src,void __user * dst,int len,__wsum sum,int * err_ptr)177 static inline __wsum csum_and_copy_to_user(const void *src,
178 void __user *dst,
179 int len, __wsum sum,
180 int *err_ptr)
181 {
182 __wsum ret;
183
184 might_sleep();
185 if (access_ok(dst, len)) {
186 stac();
187 ret = csum_partial_copy_generic(src, (__force void *)dst,
188 len, sum, NULL, err_ptr);
189 clac();
190 return ret;
191 }
192
193 if (len)
194 *err_ptr = -EFAULT;
195
196 return (__force __wsum)-1; /* invalid checksum */
197 }
198
199 #endif /* _ASM_X86_CHECKSUM_32_H */
200
