2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
6 * Copyright (C) 1995, 96, 97, 98, 99, 2001 by Ralf Baechle
7 * Copyright (C) 1999 Silicon Graphics, Inc.
8 * Copyright (C) 2001 Thiemo Seufer.
9 * Copyright (C) 2002 Maciej W. Rozycki
10 * Copyright (C) 2014 Imagination Technologies Ltd.
12 #ifndef _ASM_CHECKSUM_H
13 #define _ASM_CHECKSUM_H
15 #ifdef CONFIG_GENERIC_CSUM
16 #include <asm-generic/checksum.h>
19 #include <linux/in6.h>
21 #include <linux/uaccess.h>
24 * computes the checksum of a memory block at buff, length len,
25 * and adds in "sum" (32-bit)
27 * returns a 32-bit number suitable for feeding into itself
28 * or csum_tcpudp_magic
30 * this function must be called with even lengths, except
31 * for the last fragment, which may be odd
33 * it's best to have buff aligned on a 32-bit boundary
35 __wsum csum_partial(const void *buff, int len, __wsum sum);
37 __wsum __csum_partial_copy_from_user(const void __user *src, void *dst, int len);
38 __wsum __csum_partial_copy_to_user(const void *src, void __user *dst, int len);
40 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
42 __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len)
45 if (!access_ok(src, len))
47 return __csum_partial_copy_from_user(src, dst, len);
51 * Copy and checksum to user
53 #define HAVE_CSUM_COPY_USER
55 __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len)
58 if (!access_ok(dst, len))
60 return __csum_partial_copy_to_user(src, dst, len);
64 * the same as csum_partial, but copies from user space (but on MIPS
65 * we have just one address space, so this is identical to the above)
67 #define _HAVE_ARCH_CSUM_AND_COPY
68 __wsum __csum_partial_copy_nocheck(const void *src, void *dst, int len);
69 static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
71 return __csum_partial_copy_nocheck(src, dst, len);
75 * Fold a partial checksum without adding pseudo headers
77 static inline __sum16 csum_fold(__wsum csum)
79 u32 sum = (__force u32)csum;
82 csum = (__force __wsum)(sum < (__force u32)csum);
84 sum += (__force u32)csum;
86 return (__force __sum16)~sum;
88 #define csum_fold csum_fold
91 * This is a version of ip_compute_csum() optimized for IP headers,
92 * which always checksum on 4 octet boundaries.
94 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
97 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
99 const unsigned int *word = iph;
100 const unsigned int *stop = word + ihl;
106 carry = (csum < word[1]);
110 carry = (csum < word[2]);
114 carry = (csum < word[3]);
120 carry = (csum < *word);
123 } while (word != stop);
125 return csum_fold(csum);
127 #define ip_fast_csum ip_fast_csum
129 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
130 __u32 len, __u8 proto,
133 unsigned long tmp = (__force unsigned long)sum;
136 " .set push # csum_tcpudp_nofold\n"
140 " sltu $1, %0, %2 \n"
144 " sltu $1, %0, %3 \n"
148 " sltu $1, %0, %4 \n"
155 " dsll32 $1, %0, 0 \n"
157 " sltu $1, %0, $1 \n"
158 " dsra32 %0, %0, 0 \n"
163 : "0" ((__force unsigned long)daddr),
164 "r" ((__force unsigned long)saddr),
166 "r" ((proto + len) << 8),
170 "r" ((__force unsigned long)sum));
172 return (__force __wsum)tmp;
174 #define csum_tcpudp_nofold csum_tcpudp_nofold
177 * this routine is used for miscellaneous IP-like checksums, mainly
180 static inline __sum16 ip_compute_csum(const void *buff, int len)
182 return csum_fold(csum_partial(buff, len, 0));
185 #define _HAVE_ARCH_IPV6_CSUM
186 static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
187 const struct in6_addr *daddr,
188 __u32 len, __u8 proto,
194 " .set push # csum_ipv6_magic\n"
197 " addu %0, %5 # proto (long in network byte order)\n"
198 " sltu $1, %0, %5 \n"
201 " addu %0, %6 # csum\n"
202 " sltu $1, %0, %6 \n"
203 " lw %1, 0(%2) # four words source address\n"
206 " sltu $1, %0, %1 \n"
211 " sltu $1, %0, %1 \n"
216 " sltu $1, %0, %1 \n"
221 " sltu $1, %0, %1 \n"
226 " sltu $1, %0, %1 \n"
231 " sltu $1, %0, %1 \n"
236 " sltu $1, %0, %1 \n"
241 " sltu $1, %0, %1 \n"
243 " addu %0, $1 # Add final carry\n"
245 : "=&r" (sum), "=&r" (tmp)
246 : "r" (saddr), "r" (daddr),
247 "0" (htonl(len)), "r" (htonl(proto)), "r" (sum));
249 return csum_fold(sum);
252 #include <asm-generic/checksum.h>
253 #endif /* CONFIG_GENERIC_CSUM */
255 #endif /* _ASM_CHECKSUM_H */