1 #ifndef _I386_CHECKSUM_H
2 #define _I386_CHECKSUM_H
3
4
5 /*
6 * computes the checksum of a memory block at buff, length len,
7 * and adds in "sum" (32-bit)
8 *
9 * returns a 32-bit number suitable for feeding into itself
10 * or csum_tcpudp_magic
11 *
12 * this function must be called with even lengths, except
13 * for the last fragment, which may be odd
14 *
15 * it's best to have buff aligned on a 32-bit boundary
16 */
17 asmlinkage unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum);
18
19 /*
20 * the same as csum_partial, but copies from src while it
21 * checksums, and handles user-space pointer exceptions correctly, when needed.
22 *
23 * here even more important to align src and dst on a 32-bit (or even
24 * better 64-bit) boundary
25 */
26
27 asmlinkage unsigned int csum_partial_copy_generic( const char *src, char *dst, int len, int sum,
28 int *src_err_ptr, int *dst_err_ptr);
29
30 /*
31 * Note: when you get a NULL pointer exception here this means someone
32 * passed in an incorrect kernel address to one of these functions.
33 *
34 * If you use these functions directly please don't forget the
35 * verify_area().
36 */
37 static __inline__
csum_partial_copy_nocheck(const char * src,char * dst,int len,int sum)38 unsigned int csum_partial_copy_nocheck ( const char *src, char *dst,
39 int len, int sum)
40 {
41 return csum_partial_copy_generic ( src, dst, len, sum, NULL, NULL);
42 }
43
44 static __inline__
csum_partial_copy_from_user(const char * src,char * dst,int len,int sum,int * err_ptr)45 unsigned int csum_partial_copy_from_user ( const char *src, char *dst,
46 int len, int sum, int *err_ptr)
47 {
48 return csum_partial_copy_generic ( src, dst, len, sum, err_ptr, NULL);
49 }
50
51 /*
52 * These are the old (and unsafe) way of doing checksums, a warning message will be
53 * printed if they are used and an exeption occurs.
54 *
55 * these functions should go away after some time.
56 */
57
58 #define csum_partial_copy_fromuser csum_partial_copy
59 unsigned int csum_partial_copy( const char *src, char *dst, int len, int sum);
60
61 /*
62 * This is a version of ip_compute_csum() optimized for IP headers,
63 * which always checksum on 4 octet boundaries.
64 *
65 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
66 * Arnt Gulbrandsen.
67 */
ip_fast_csum(unsigned char * iph,unsigned int ihl)68 static inline unsigned short ip_fast_csum(unsigned char * iph,
69 unsigned int ihl)
70 {
71 unsigned int sum;
72
73 __asm__ __volatile__(
74 "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 ipl
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(sum);
98 }
99
100 /*
101 * Fold a partial checksum
102 */
103
csum_fold(unsigned int sum)104 static inline unsigned int csum_fold(unsigned int sum)
105 {
106 __asm__(
107 "addl %1, %0 ;\n"
108 "adcl $0xffff, %0 ;\n"
109 : "=r" (sum)
110 : "r" (sum << 16), "0" (sum & 0xffff0000)
111 );
112 return (~sum) >> 16;
113 }
114
csum_tcpudp_nofold(unsigned long saddr,unsigned long daddr,unsigned short len,unsigned short proto,unsigned int sum)115 static inline unsigned long csum_tcpudp_nofold(unsigned long saddr,
116 unsigned long daddr,
117 unsigned short len,
118 unsigned short proto,
119 unsigned int sum)
120 {
121 __asm__(
122 "addl %1, %0 ;\n"
123 "adcl %2, %0 ;\n"
124 "adcl %3, %0 ;\n"
125 "adcl $0, %0 ;\n"
126 : "=r" (sum)
127 : "g" (daddr), "g"(saddr), "g"((ntohs(len)<<16)+proto*256), "0"(sum));
128 return sum;
129 }
130
131 /*
132 * computes the checksum of the TCP/UDP pseudo-header
133 * returns a 16-bit checksum, already complemented
134 */
csum_tcpudp_magic(unsigned long saddr,unsigned long daddr,unsigned short len,unsigned short proto,unsigned int sum)135 static inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
136 unsigned long daddr,
137 unsigned short len,
138 unsigned short proto,
139 unsigned int sum)
140 {
141 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
142 }
143
144 /*
145 * this routine is used for miscellaneous IP-like checksums, mainly
146 * in icmp.c
147 */
148
ip_compute_csum(unsigned char * buff,int len)149 static inline unsigned short ip_compute_csum(unsigned char * buff, int len)
150 {
151 return csum_fold (csum_partial(buff, len, 0));
152 }
153
154 #define _HAVE_ARCH_IPV6_CSUM
csum_ipv6_magic(struct in6_addr * saddr,struct in6_addr * daddr,__u32 len,unsigned short proto,unsigned int sum)155 static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
156 struct in6_addr *daddr,
157 __u32 len,
158 unsigned short proto,
159 unsigned int sum)
160 {
161 __asm__(
162 "addl 0(%1), %0 ;\n"
163 "adcl 4(%1), %0 ;\n"
164 "adcl 8(%1), %0 ;\n"
165 "adcl 12(%1), %0 ;\n"
166 "adcl 0(%2), %0 ;\n"
167 "adcl 4(%2), %0 ;\n"
168 "adcl 8(%2), %0 ;\n"
169 "adcl 12(%2), %0 ;\n"
170 "adcl %3, %0 ;\n"
171 "adcl %4, %0 ;\n"
172 "adcl $0, %0 ;\n"
173 : "=&r" (sum)
174 : "r" (saddr), "r" (daddr),
175 "r"(htonl(len)), "r"(htonl(proto)), "0"(sum));
176
177 return csum_fold(sum);
178 }
179
180 /*
181 * Copy and checksum to user
182 */
183 #define HAVE_CSUM_COPY_USER
csum_and_copy_to_user(const char * src,char * dst,int len,int sum,int * err_ptr)184 static __inline__ unsigned int csum_and_copy_to_user(const char *src, char *dst,
185 int len, int sum, int *err_ptr)
186 {
187 if (access_ok(VERIFY_WRITE, dst, len))
188 return csum_partial_copy_generic(src, dst, len, sum, NULL, err_ptr);
189
190 if (len)
191 *err_ptr = -EFAULT;
192
193 return -1; /* invalid checksum */
194 }
195
196 #endif
197