1 /* SPDX-License-Identifier: GPL-2.0 */
3 * arch/arm/include/asm/checksum.h
7 * Copyright (C) Original authors of ../asm-i386/checksum.h
8 * Copyright (C) 1996-1999 Russell King
10 #ifndef __ASM_ARM_CHECKSUM_H
11 #define __ASM_ARM_CHECKSUM_H
13 #include <linux/in6.h>
16 * computes the checksum of a memory block at buff, length len,
17 * and adds in "sum" (32-bit)
19 * returns a 32-bit number suitable for feeding into itself
20 * or csum_tcpudp_magic
22 * this function must be called with even lengths, except
23 * for the last fragment, which may be odd
25 * it's best to have buff aligned on a 32-bit boundary
27 __wsum csum_partial(const void *buff, int len, __wsum sum);
30 * the same as csum_partial, but copies from src while it
31 * checksums, and handles user-space pointer exceptions correctly, when needed.
33 * here even more important to align src and dst on a 32-bit (or even
34 * better 64-bit) boundary
38 csum_partial_copy_nocheck(const void *src, void *dst, int len);
41 csum_partial_copy_from_user(const void __user *src, void *dst, int len);
43 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
44 #define _HAVE_ARCH_CSUM_AND_COPY
46 __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len)
48 if (!access_ok(src, len))
51 return csum_partial_copy_from_user(src, dst, len);
55 * Fold a partial checksum without adding pseudo headers
57 static inline __sum16 csum_fold(__wsum sum)
60 "add %0, %1, %1, ror #16 @ csum_fold"
64 return (__force __sum16)(~(__force u32)sum >> 16);
68 * This is a version of ip_compute_csum() optimized for IP headers,
69 * which always checksum on 4 octet boundaries.
72 ip_fast_csum(const void *iph, unsigned int ihl)
78 "ldr %0, [%1], #4 @ ip_fast_csum \n\
85 1: adcs %0, %0, %3 \n\
87 tst %2, #15 @ do this carefully \n\
88 subne %2, %2, #1 @ without destroying \n\
89 bne 1b @ the carry flag \n\
92 : "=r" (sum), "=r" (iph), "=r" (ihl), "=r" (tmp1)
93 : "1" (iph), "2" (ihl)
95 return csum_fold(sum);
99 csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
100 __u8 proto, __wsum sum)
102 u32 lenprot = len + proto;
103 if (__builtin_constant_p(sum) && sum == 0) {
105 "adds %0, %1, %2 @ csum_tcpudp_nofold0 \n\t"
107 "adcs %0, %0, %3 \n\t"
109 "adcs %0, %0, %3, ror #8 \n\t"
113 : "r" (daddr), "r" (saddr), "r" (lenprot)
117 "adds %0, %1, %2 @ csum_tcpudp_nofold \n\t"
118 "adcs %0, %0, %3 \n\t"
120 "adcs %0, %0, %4 \n\t"
122 "adcs %0, %0, %4, ror #8 \n\t"
126 : "r" (sum), "r" (daddr), "r" (saddr), "r" (lenprot)
132 * computes the checksum of the TCP/UDP pseudo-header
133 * returns a 16-bit checksum, already complemented
135 static inline __sum16
136 csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len,
137 __u8 proto, __wsum sum)
139 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
144 * this routine is used for miscellaneous IP-like checksums, mainly
147 static inline __sum16
148 ip_compute_csum(const void *buff, int len)
150 return csum_fold(csum_partial(buff, len, 0));
153 #define _HAVE_ARCH_IPV6_CSUM
155 __csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr, __be32 len,
156 __be32 proto, __wsum sum);
158 static inline __sum16
159 csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr,
160 __u32 len, __u8 proto, __wsum sum)
162 return csum_fold(__csum_ipv6_magic(saddr, daddr, htonl(len),