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TOMOYO Linux Cross Reference
Linux/include/asm-sh/checksum.h

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  1 #ifndef __ASM_SH_CHECKSUM_H
  2 #define __ASM_SH_CHECKSUM_H
  3 
  4 /*
  5  * This file is subject to the terms and conditions of the GNU General Public
  6  * License.  See the file "COPYING" in the main directory of this archive
  7  * for more details.
  8  *
  9  * Copyright (C) 1999 by Kaz Kojima & Niibe Yutaka
 10  */
 11 
 12 #include <linux/config.h>
 13 
 14 /*
 15  * computes the checksum of a memory block at buff, length len,
 16  * and adds in "sum" (32-bit)
 17  *
 18  * returns a 32-bit number suitable for feeding into itself
 19  * or csum_tcpudp_magic
 20  *
 21  * this function must be called with even lengths, except
 22  * for the last fragment, which may be odd
 23  *
 24  * it's best to have buff aligned on a 32-bit boundary
 25  */
 26 asmlinkage unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum);
 27 
 28 /*
 29  * the same as csum_partial, but copies from src while it
 30  * checksums, and handles user-space pointer exceptions correctly, when needed.
 31  *
 32  * here even more important to align src and dst on a 32-bit (or even
 33  * better 64-bit) boundary
 34  */
 35 
 36 asmlinkage unsigned int csum_partial_copy_generic( const char *src, char *dst, int len, int sum,
 37                                                    int *src_err_ptr, int *dst_err_ptr);
 38 
 39 /*
 40  *      Note: when you get a NULL pointer exception here this means someone
 41  *      passed in an incorrect kernel address to one of these functions. 
 42  *      
 43  *      If you use these functions directly please don't forget the 
 44  *      verify_area().
 45  */
 46 static __inline__
 47 unsigned int csum_partial_copy_nocheck ( const char *src, char *dst,
 48                                         int len, int sum)
 49 {
 50         return csum_partial_copy_generic ( src, dst, len, sum, NULL, NULL);
 51 }
 52 
 53 static __inline__
 54 unsigned int csum_partial_copy_from_user ( const char *src, char *dst,
 55                                                 int len, int sum, int *err_ptr)
 56 {
 57         return csum_partial_copy_generic ( src, dst, len, sum, err_ptr, NULL);
 58 }
 59 
 60 /*
 61  *      Fold a partial checksum
 62  */
 63 
 64 static __inline__ unsigned int csum_fold(unsigned int sum)
 65 {
 66         unsigned int __dummy;
 67         __asm__("swap.w %0, %1\n\t"
 68                 "extu.w %0, %0\n\t"
 69                 "extu.w %1, %1\n\t"
 70                 "add    %1, %0\n\t"
 71                 "swap.w %0, %1\n\t"
 72                 "add    %1, %0\n\t"
 73                 "not    %0, %0\n\t"
 74                 : "=r" (sum), "=&r" (__dummy)
 75                 : "" (sum)
 76                 : "t");
 77         return sum;
 78 }
 79 
 80 /*
 81  *      This is a version of ip_compute_csum() optimized for IP headers,
 82  *      which always checksum on 4 octet boundaries.
 83  *
 84  *      i386 version by Jorge Cwik <jorge@laser.satlink.net>, adapted
 85  *      for linux by * Arnt Gulbrandsen.
 86  */
 87 static __inline__ unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl)
 88 {
 89         unsigned int sum, __dummy0, __dummy1;
 90 
 91         __asm__ __volatile__(
 92                 "mov.l  @%1+, %0\n\t"
 93                 "mov.l  @%1+, %3\n\t"
 94                 "add    #-2, %2\n\t"
 95                 "clrt\n\t"
 96                 "1:\t"
 97                 "addc   %3, %0\n\t"
 98                 "movt   %4\n\t"
 99                 "mov.l  @%1+, %3\n\t"
100                 "dt     %2\n\t"
101                 "bf/s   1b\n\t"
102                 " cmp/eq #1, %4\n\t"
103                 "addc   %3, %0\n\t"
104                 "addc   %2, %0"     /* Here %2 is 0, add carry-bit */
105         /* Since the input registers which are loaded with iph and ihl
106            are modified, we must also specify them as outputs, or gcc
107            will assume they contain their original values. */
108         : "=r" (sum), "=r" (iph), "=r" (ihl), "=&r" (__dummy0), "=&z" (__dummy1)
109         : "1" (iph), "2" (ihl)
110         : "t");
111 
112         return  csum_fold(sum);
113 }
114 
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 #ifdef __LITTLE_ENDIAN__
122         unsigned long len_proto = (ntohs(len)<<16)+proto*256;
123 #else
124         unsigned long len_proto = (proto<<16)+len;
125 #endif
126         __asm__("clrt\n\t"
127                 "addc   %0, %1\n\t"
128                 "addc   %2, %1\n\t"
129                 "addc   %3, %1\n\t"
130                 "movt   %0\n\t"
131                 "add    %1, %0"
132                 : "=r" (sum), "=r" (len_proto)
133                 : "r" (daddr), "r" (saddr), "1" (len_proto), "" (sum)
134                 : "t");
135         return sum;
136 }
137 
138 /*
139  * computes the checksum of the TCP/UDP pseudo-header
140  * returns a 16-bit checksum, already complemented
141  */
142 static __inline__ unsigned short int csum_tcpudp_magic(unsigned long saddr,
143                                                        unsigned long daddr,
144                                                        unsigned short len,
145                                                        unsigned short proto,
146                                                        unsigned int sum) 
147 {
148         return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
149 }
150 
151 /*
152  * this routine is used for miscellaneous IP-like checksums, mainly
153  * in icmp.c
154  */
155 
156 static __inline__ unsigned short ip_compute_csum(unsigned char * buff, int len)
157 {
158     return csum_fold (csum_partial(buff, len, 0));
159 }
160 
161 #define _HAVE_ARCH_IPV6_CSUM
162 #ifdef CONFIG_IPV6
163 static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
164                                                      struct in6_addr *daddr,
165                                                      __u32 len,
166                                                      unsigned short proto,
167                                                      unsigned int sum) 
168 {
169         unsigned int __dummy;
170         __asm__("clrt\n\t"
171                 "mov.l  @(0,%2), %1\n\t"
172                 "addc   %1, %0\n\t"
173                 "mov.l  @(4,%2), %1\n\t"
174                 "addc   %1, %0\n\t"
175                 "mov.l  @(8,%2), %1\n\t"
176                 "addc   %1, %0\n\t"
177                 "mov.l  @(12,%2), %1\n\t"
178                 "addc   %1, %0\n\t"
179                 "mov.l  @(0,%3), %1\n\t"
180                 "addc   %1, %0\n\t"
181                 "mov.l  @(4,%3), %1\n\t"
182                 "addc   %1, %0\n\t"
183                 "mov.l  @(8,%3), %1\n\t"
184                 "addc   %1, %0\n\t"
185                 "mov.l  @(12,%3), %1\n\t"
186                 "addc   %1, %0\n\t"
187                 "addc   %4, %0\n\t"
188                 "addc   %5, %0\n\t"
189                 "movt   %1\n\t"
190                 "add    %1, %0\n"
191                 : "=r" (sum), "=&r" (__dummy)
192                 : "r" (saddr), "r" (daddr), 
193                   "r" (htonl(len)), "r" (htonl(proto)), "" (sum)
194                 : "t");
195 
196         return csum_fold(sum);
197 }
198 #endif
199 
200 /* 
201  *      Copy and checksum to user
202  */
203 #define HAVE_CSUM_COPY_USER
204 static __inline__ unsigned int csum_and_copy_to_user (const char *src, char *dst,
205                                     int len, int sum, int *err_ptr)
206 {
207         if (access_ok(VERIFY_WRITE, dst, len))
208                 return csum_partial_copy_generic(src, dst, len, sum, NULL, err_ptr);
209 
210         if (len)
211                 *err_ptr = -EFAULT;
212 
213         return -1; /* invalid checksum */
214 }
215 #endif /* __ASM_SH_CHECKSUM_H */
216 

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