1 #ifndef _ASM_X86_CHECKSUM_32_H
2 #define _ASM_X86_CHECKSUM_32_H
3
4 #include <linux/in6.h>
5
6 #include <asm/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 might_sleep();
53 return csum_partial_copy_generic((__force void *)src, dst,
54 len, sum, err_ptr, NULL);
55 }
56
57 /*
58 * This is a version of ip_compute_csum() optimized for IP headers,
59 * which always checksum on 4 octet boundaries.
60 *
61 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
62 * Arnt Gulbrandsen.
63 */
ip_fast_csum(const void * iph,unsigned int ihl)64 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
65 {
66 unsigned int sum;
67
68 asm volatile("movl (%1), %0 ;\n"
69 "subl $4, %2 ;\n"
70 "jbe 2f ;\n"
71 "addl 4(%1), %0 ;\n"
72 "adcl 8(%1), %0 ;\n"
73 "adcl 12(%1), %0;\n"
74 "1: adcl 16(%1), %0 ;\n"
75 "lea 4(%1), %1 ;\n"
76 "decl %2 ;\n"
77 "jne 1b ;\n"
78 "adcl $0, %0 ;\n"
79 "movl %0, %2 ;\n"
80 "shrl $16, %0 ;\n"
81 "addw %w2, %w0 ;\n"
82 "adcl $0, %0 ;\n"
83 "notl %0 ;\n"
84 "2: ;\n"
85 /* Since the input registers which are loaded with iph and ihl
86 are modified, we must also specify them as outputs, or gcc
87 will assume they contain their original values. */
88 : "=r" (sum), "=r" (iph), "=r" (ihl)
89 : "1" (iph), "2" (ihl)
90 : "memory");
91 return (__force __sum16)sum;
92 }
93
94 /*
95 * Fold a partial checksum
96 */
97
csum_fold(__wsum sum)98 static inline __sum16 csum_fold(__wsum sum)
99 {
100 asm("addl %1, %0 ;\n"
101 "adcl $0xffff, %0 ;\n"
102 : "=r" (sum)
103 : "r" ((__force u32)sum << 16),
104 "0" ((__force u32)sum & 0xffff0000));
105 return (__force __sum16)(~(__force u32)sum >> 16);
106 }
107
csum_tcpudp_nofold(__be32 saddr,__be32 daddr,unsigned short len,unsigned short proto,__wsum sum)108 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
109 unsigned short len,
110 unsigned short proto,
111 __wsum sum)
112 {
113 asm("addl %1, %0 ;\n"
114 "adcl %2, %0 ;\n"
115 "adcl %3, %0 ;\n"
116 "adcl $0, %0 ;\n"
117 : "=r" (sum)
118 : "g" (daddr), "g"(saddr),
119 "g" ((len + proto) << 8), "0" (sum));
120 return sum;
121 }
122
123 /*
124 * computes the checksum of the TCP/UDP pseudo-header
125 * returns a 16-bit checksum, already complemented
126 */
csum_tcpudp_magic(__be32 saddr,__be32 daddr,unsigned short len,unsigned short proto,__wsum sum)127 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
128 unsigned short len,
129 unsigned short proto,
130 __wsum sum)
131 {
132 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
133 }
134
135 /*
136 * this routine is used for miscellaneous IP-like checksums, mainly
137 * in icmp.c
138 */
139
ip_compute_csum(const void * buff,int len)140 static inline __sum16 ip_compute_csum(const void *buff, int len)
141 {
142 return csum_fold(csum_partial(buff, len, 0));
143 }
144
145 #define _HAVE_ARCH_IPV6_CSUM
csum_ipv6_magic(const struct in6_addr * saddr,const struct in6_addr * daddr,__u32 len,unsigned short proto,__wsum sum)146 static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
147 const struct in6_addr *daddr,
148 __u32 len, unsigned short proto,
149 __wsum sum)
150 {
151 asm("addl 0(%1), %0 ;\n"
152 "adcl 4(%1), %0 ;\n"
153 "adcl 8(%1), %0 ;\n"
154 "adcl 12(%1), %0 ;\n"
155 "adcl 0(%2), %0 ;\n"
156 "adcl 4(%2), %0 ;\n"
157 "adcl 8(%2), %0 ;\n"
158 "adcl 12(%2), %0 ;\n"
159 "adcl %3, %0 ;\n"
160 "adcl %4, %0 ;\n"
161 "adcl $0, %0 ;\n"
162 : "=&r" (sum)
163 : "r" (saddr), "r" (daddr),
164 "r" (htonl(len)), "r" (htonl(proto)), "0" (sum)
165 : "memory");
166
167 return csum_fold(sum);
168 }
169
170 /*
171 * Copy and checksum to user
172 */
173 #define HAVE_CSUM_COPY_USER
csum_and_copy_to_user(const void * src,void __user * dst,int len,__wsum sum,int * err_ptr)174 static inline __wsum csum_and_copy_to_user(const void *src,
175 void __user *dst,
176 int len, __wsum sum,
177 int *err_ptr)
178 {
179 might_sleep();
180 if (access_ok(VERIFY_WRITE, dst, len))
181 return csum_partial_copy_generic(src, (__force void *)dst,
182 len, sum, NULL, err_ptr);
183
184 if (len)
185 *err_ptr = -EFAULT;
186
187 return (__force __wsum)-1; /* invalid checksum */
188 }
189
190 #endif /* _ASM_X86_CHECKSUM_32_H */
191