1#ifndef _I386_CHECKSUM_H
2#define _I386_CHECKSUM_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, int *src_err_ptr, int *dst_err_ptr);
32
33/*
34 *	Note: when you get a NULL pointer exception here this means someone
35 *	passed in an incorrect kernel address to one of these functions.
36 *
37 *	If you use these functions directly please don't forget the
38 *	access_ok().
39 */
40static __inline__
41__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__
48__wsum csum_partial_copy_from_user(const void __user *src, void *dst,
49						int len, __wsum sum, int *err_ptr)
50{
51	might_sleep();
52	return csum_partial_copy_generic((__force void *)src, dst,
53					len, sum, err_ptr, NULL);
54}
55
56/*
57 *	This is a version of ip_compute_csum() optimized for IP headers,
58 *	which always checksum on 4 octet boundaries.
59 *
60 *	By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
61 *	Arnt Gulbrandsen.
62 */
63static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
64{
65	unsigned int sum;
66
67	__asm__ __volatile__(
68	    "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
98static inline __sum16 csum_fold(__wsum sum)
99{
100	__asm__(
101		"addl %1, %0		;\n"
102		"adcl $0xffff, %0	;\n"
103		: "=r" (sum)
104		: "r" ((__force u32)sum << 16),
105		  "0" ((__force u32)sum & 0xffff0000)
106	);
107	return (__force __sum16)(~(__force u32)sum >> 16);
108}
109
110static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
111					   unsigned short len,
112					   unsigned short proto,
113					   __wsum sum)
114{
115    __asm__(
116	"addl %1, %0	;\n"
117	"adcl %2, %0	;\n"
118	"adcl %3, %0	;\n"
119	"adcl $0, %0	;\n"
120	: "=r" (sum)
121	: "g" (daddr), "g"(saddr), "g"((len + proto) << 8), "0"(sum));
122    return sum;
123}
124
125/*
126 * computes the checksum of the TCP/UDP pseudo-header
127 * returns a 16-bit checksum, already complemented
128 */
129static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
130						   unsigned short len,
131						   unsigned short proto,
132						   __wsum sum)
133{
134	return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
135}
136
137/*
138 * this routine is used for miscellaneous IP-like checksums, mainly
139 * in icmp.c
140 */
141
142static inline __sum16 ip_compute_csum(const void *buff, int len)
143{
144    return csum_fold (csum_partial(buff, len, 0));
145}
146
147#define _HAVE_ARCH_IPV6_CSUM
148static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
149					  const struct in6_addr *daddr,
150					  __u32 len, unsigned short proto,
151					  __wsum sum)
152{
153	__asm__(
154		"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
169	return csum_fold(sum);
170}
171
172/*
173 *	Copy and checksum to user
174 */
175#define HAVE_CSUM_COPY_USER
176static __inline__ __wsum csum_and_copy_to_user(const void *src,
177						     void __user *dst,
178						     int len, __wsum sum,
179						     int *err_ptr)
180{
181	might_sleep();
182	if (access_ok(VERIFY_WRITE, dst, len))
183		return csum_partial_copy_generic(src, (__force void *)dst, len, sum, NULL, err_ptr);
184
185	if (len)
186		*err_ptr = -EFAULT;
187
188	return (__force __wsum)-1; /* invalid checksum */
189}
190
191#endif
192