2 * arch/arm/include/asm/checksum.h
6 * Copyright (C) Original authors of ../asm-i386/checksum.h
7 * Copyright (C) 1996-1999 Russell King
9 #ifndef __ASM_ARM_CHECKSUM_H
10 #define __ASM_ARM_CHECKSUM_H
12 #include <linux/in6.h>
15 * computes the checksum of a memory block at buff, length len,
16 * and adds in "sum" (32-bit)
18 * returns a 32-bit number suitable for feeding into itself
19 * or csum_tcpudp_magic
21 * this function must be called with even lengths, except
22 * for the last fragment, which may be odd
24 * it's best to have buff aligned on a 32-bit boundary
26 __wsum csum_partial(const void *buff, int len, __wsum sum);
29 * the same as csum_partial, but copies from src while it
30 * checksums, and handles user-space pointer exceptions correctly, when needed.
32 * here even more important to align src and dst on a 32-bit (or even
33 * better 64-bit) boundary
37 csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum);
40 csum_partial_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *err_ptr);
43 * Fold a partial checksum without adding pseudo headers
45 static inline __sum16 csum_fold(__wsum sum)
48 "add %0, %1, %1, ror #16 @ csum_fold"
52 return (__force __sum16)(~(__force u32)sum >> 16);
56 * This is a version of ip_compute_csum() optimized for IP headers,
57 * which always checksum on 4 octet boundaries.
60 ip_fast_csum(const void *iph, unsigned int ihl)
66 "ldr %0, [%1], #4 @ ip_fast_csum \n\
73 1: adcs %0, %0, %3 \n\
75 tst %2, #15 @ do this carefully \n\
76 subne %2, %2, #1 @ without destroying \n\
77 bne 1b @ the carry flag \n\
80 : "=r" (sum), "=r" (iph), "=r" (ihl), "=r" (tmp1)
81 : "1" (iph), "2" (ihl)
83 return csum_fold(sum);
87 csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
88 __u8 proto, __wsum sum)
90 u32 lenprot = len + proto;
91 if (__builtin_constant_p(sum) && sum == 0) {
93 "adds %0, %1, %2 @ csum_tcpudp_nofold0 \n\t"
95 "adcs %0, %0, %3 \n\t"
97 "adcs %0, %0, %3, ror #8 \n\t"
101 : "r" (daddr), "r" (saddr), "r" (lenprot)
105 "adds %0, %1, %2 @ csum_tcpudp_nofold \n\t"
106 "adcs %0, %0, %3 \n\t"
108 "adcs %0, %0, %4 \n\t"
110 "adcs %0, %0, %4, ror #8 \n\t"
114 : "r" (sum), "r" (daddr), "r" (saddr), "r" (lenprot)
120 * computes the checksum of the TCP/UDP pseudo-header
121 * returns a 16-bit checksum, already complemented
123 static inline __sum16
124 csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len,
125 __u8 proto, __wsum sum)
127 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
132 * this routine is used for miscellaneous IP-like checksums, mainly
135 static inline __sum16
136 ip_compute_csum(const void *buff, int len)
138 return csum_fold(csum_partial(buff, len, 0));
141 #define _HAVE_ARCH_IPV6_CSUM
143 __csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr, __be32 len,
144 __be32 proto, __wsum sum);
146 static inline __sum16
147 csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr,
148 __u32 len, __u8 proto, __wsum sum)
150 return csum_fold(__csum_ipv6_magic(saddr, daddr, htonl(len),