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 <asm/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_kernel(const void *src, void *dst,
38 int len, __wsum sum, int *err_ptr);
40 __wsum __csum_partial_copy_from_user(const void *src, void *dst,
41 int len, __wsum sum, int *err_ptr);
42 __wsum __csum_partial_copy_to_user(const void *src, void *dst,
43 int len, __wsum sum, int *err_ptr);
45 * this is a new version of the above that records errors it finds in *errp,
46 * but continues and zeros the rest of the buffer.
49 __wsum csum_partial_copy_from_user(const void __user *src, void *dst, int len,
50 __wsum sum, int *err_ptr)
53 if (segment_eq(get_fs(), get_ds()))
54 return __csum_partial_copy_kernel((__force void *)src, dst,
57 return __csum_partial_copy_from_user((__force void *)src, dst,
61 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
63 __wsum csum_and_copy_from_user(const void __user *src, void *dst,
64 int len, __wsum sum, int *err_ptr)
66 if (access_ok(VERIFY_READ, src, len))
67 return csum_partial_copy_from_user(src, dst, len, sum,
76 * Copy and checksum to user
78 #define HAVE_CSUM_COPY_USER
80 __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len,
81 __wsum sum, int *err_ptr)
84 if (access_ok(VERIFY_WRITE, dst, len)) {
85 if (segment_eq(get_fs(), get_ds()))
86 return __csum_partial_copy_kernel(src,
90 return __csum_partial_copy_to_user(src,
97 return (__force __wsum)-1; /* invalid checksum */
101 * the same as csum_partial, but copies from user space (but on MIPS
102 * we have just one address space, so this is identical to the above)
104 __wsum csum_partial_copy_nocheck(const void *src, void *dst,
105 int len, __wsum sum);
106 #define csum_partial_copy_nocheck csum_partial_copy_nocheck
109 * Fold a partial checksum without adding pseudo headers
111 static inline __sum16 csum_fold(__wsum csum)
113 u32 sum = (__force u32)csum;;
120 return (__force __sum16)~sum;
122 #define csum_fold csum_fold
125 * This is a version of ip_compute_csum() optimized for IP headers,
126 * which always checksum on 4 octet boundaries.
128 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
131 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
133 const unsigned int *word = iph;
134 const unsigned int *stop = word + ihl;
140 carry = (csum < word[1]);
144 carry = (csum < word[2]);
148 carry = (csum < word[3]);
154 carry = (csum < *word);
157 } while (word != stop);
159 return csum_fold(csum);
161 #define ip_fast_csum ip_fast_csum
163 static inline __wsum csum_tcpudp_nofold(__be32 saddr,
164 __be32 daddr, unsigned short len, unsigned short proto,
168 " .set push # csum_tcpudp_nofold\n"
172 " sltu $1, %0, %2 \n"
176 " sltu $1, %0, %3 \n"
180 " sltu $1, %0, %4 \n"
187 " dsll32 $1, %0, 0 \n"
189 " dsra32 %0, %0, 0 \n"
193 : "0" ((__force unsigned long)daddr),
194 "r" ((__force unsigned long)saddr),
196 "r" ((proto + len) << 8),
200 "r" ((__force unsigned long)sum));
204 #define csum_tcpudp_nofold csum_tcpudp_nofold
207 * this routine is used for miscellaneous IP-like checksums, mainly
210 static inline __sum16 ip_compute_csum(const void *buff, int len)
212 return csum_fold(csum_partial(buff, len, 0));
215 #define _HAVE_ARCH_IPV6_CSUM
216 static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
217 const struct in6_addr *daddr,
218 __u32 len, unsigned short proto,
224 " .set push # csum_ipv6_magic\n"
227 " addu %0, %5 # proto (long in network byte order)\n"
228 " sltu $1, %0, %5 \n"
231 " addu %0, %6 # csum\n"
232 " sltu $1, %0, %6 \n"
233 " lw %1, 0(%2) # four words source address\n"
236 " sltu $1, %0, %1 \n"
241 " sltu $1, %0, %1 \n"
246 " sltu $1, %0, %1 \n"
251 " sltu $1, %0, %1 \n"
256 " sltu $1, %0, %1 \n"
261 " sltu $1, %0, %1 \n"
266 " sltu $1, %0, %1 \n"
271 " sltu $1, %0, %1 \n"
273 " addu %0, $1 # Add final carry\n"
275 : "=&r" (sum), "=&r" (tmp)
276 : "r" (saddr), "r" (daddr),
277 "0" (htonl(len)), "r" (htonl(proto)), "r" (sum));
279 return csum_fold(sum);
282 #include <asm-generic/checksum.h>
283 #endif /* CONFIG_GENERIC_CSUM */
285 #endif /* _ASM_CHECKSUM_H */