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 */
20asmlinkage __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
30asmlinkage __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 */
41static 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
47static 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 */
70static 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
104static 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
114static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
115					unsigned short len,
116					unsigned short proto,
117					__wsum sum)
118{
119	asm("addl %1, %0	;\n"
120	    "adcl %2, %0	;\n"
121	    "adcl %3, %0	;\n"
122	    "adcl $0, %0	;\n"
123	    : "=r" (sum)
124	    : "g" (daddr), "g"(saddr),
125	      "g" ((len + proto) << 8), "0" (sum));
126	return sum;
127}
128
129/*
130 * computes the checksum of the TCP/UDP pseudo-header
131 * returns a 16-bit checksum, already complemented
132 */
133static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
134					unsigned short len,
135					unsigned short proto,
136					__wsum sum)
137{
138	return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
139}
140
141/*
142 * this routine is used for miscellaneous IP-like checksums, mainly
143 * in icmp.c
144 */
145
146static inline __sum16 ip_compute_csum(const void *buff, int len)
147{
148    return csum_fold(csum_partial(buff, len, 0));
149}
150
151#define _HAVE_ARCH_IPV6_CSUM
152static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
153				      const struct in6_addr *daddr,
154				      __u32 len, unsigned short proto,
155				      __wsum sum)
156{
157	asm("addl 0(%1), %0	;\n"
158	    "adcl 4(%1), %0	;\n"
159	    "adcl 8(%1), %0	;\n"
160	    "adcl 12(%1), %0	;\n"
161	    "adcl 0(%2), %0	;\n"
162	    "adcl 4(%2), %0	;\n"
163	    "adcl 8(%2), %0	;\n"
164	    "adcl 12(%2), %0	;\n"
165	    "adcl %3, %0	;\n"
166	    "adcl %4, %0	;\n"
167	    "adcl $0, %0	;\n"
168	    : "=&r" (sum)
169	    : "r" (saddr), "r" (daddr),
170	      "r" (htonl(len)), "r" (htonl(proto)), "0" (sum)
171	    : "memory");
172
173	return csum_fold(sum);
174}
175
176/*
177 *	Copy and checksum to user
178 */
179#define HAVE_CSUM_COPY_USER
180static inline __wsum csum_and_copy_to_user(const void *src,
181					   void __user *dst,
182					   int len, __wsum sum,
183					   int *err_ptr)
184{
185	__wsum ret;
186
187	might_sleep();
188	if (access_ok(VERIFY_WRITE, dst, len)) {
189		stac();
190		ret = csum_partial_copy_generic(src, (__force void *)dst,
191						len, sum, NULL, err_ptr);
192		clac();
193		return ret;
194	}
195
196	if (len)
197		*err_ptr = -EFAULT;
198
199	return (__force __wsum)-1; /* invalid checksum */
200}
201
202#endif /* _ASM_X86_CHECKSUM_32_H */
203