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Diffstat (limited to 'arch/arm/include/asm/checksum.h')
| -rw-r--r-- | arch/arm/include/asm/checksum.h | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/arch/arm/include/asm/checksum.h b/arch/arm/include/asm/checksum.h new file mode 100644 index 000000000..f0f54aef3 --- /dev/null +++ b/arch/arm/include/asm/checksum.h @@ -0,0 +1,165 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * arch/arm/include/asm/checksum.h + * + * IP checksum routines + * + * Copyright (C) Original authors of ../asm-i386/checksum.h + * Copyright (C) 1996-1999 Russell King + */ +#ifndef __ASM_ARM_CHECKSUM_H +#define __ASM_ARM_CHECKSUM_H + +#include <linux/in6.h> + +/* + * computes the checksum of a memory block at buff, length len, + * and adds in "sum" (32-bit) + * + * returns a 32-bit number suitable for feeding into itself + * or csum_tcpudp_magic + * + * this function must be called with even lengths, except + * for the last fragment, which may be odd + * + * it's best to have buff aligned on a 32-bit boundary + */ +__wsum csum_partial(const void *buff, int len, __wsum sum); + +/* + * the same as csum_partial, but copies from src while it + * checksums, and handles user-space pointer exceptions correctly, when needed. + * + * here even more important to align src and dst on a 32-bit (or even + * better 64-bit) boundary + */ + +__wsum +csum_partial_copy_nocheck(const void *src, void *dst, int len); + +__wsum +csum_partial_copy_from_user(const void __user *src, void *dst, int len); + +#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER +#define _HAVE_ARCH_CSUM_AND_COPY +static inline +__wsum csum_and_copy_from_user(const void __user *src, void *dst, int len) +{ + if (!access_ok(src, len)) + return 0; + + return csum_partial_copy_from_user(src, dst, len); +} + +/* + * Fold a partial checksum without adding pseudo headers + */ +static inline __sum16 csum_fold(__wsum sum) +{ + __asm__( + "add %0, %1, %1, ror #16 @ csum_fold" + : "=r" (sum) + : "r" (sum) + : "cc"); + return (__force __sum16)(~(__force u32)sum >> 16); +} + +/* + * This is a version of ip_compute_csum() optimized for IP headers, + * which always checksum on 4 octet boundaries. + */ +static inline __sum16 +ip_fast_csum(const void *iph, unsigned int ihl) +{ + unsigned int tmp1; + __wsum sum; + + __asm__ __volatile__( + "ldr %0, [%1], #4 @ ip_fast_csum \n\ + ldr %3, [%1], #4 \n\ + sub %2, %2, #5 \n\ + adds %0, %0, %3 \n\ + ldr %3, [%1], #4 \n\ + adcs %0, %0, %3 \n\ + ldr %3, [%1], #4 \n\ +1: adcs %0, %0, %3 \n\ + ldr %3, [%1], #4 \n\ + tst %2, #15 @ do this carefully \n\ + subne %2, %2, #1 @ without destroying \n\ + bne 1b @ the carry flag \n\ + adcs %0, %0, %3 \n\ + adc %0, %0, #0" + : "=r" (sum), "=r" (iph), "=r" (ihl), "=r" (tmp1) + : "1" (iph), "2" (ihl) + : "cc", "memory"); + return csum_fold(sum); +} + +static inline __wsum +csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len, + __u8 proto, __wsum sum) +{ + u32 lenprot = len + proto; + if (__builtin_constant_p(sum) && sum == 0) { + __asm__( + "adds %0, %1, %2 @ csum_tcpudp_nofold0 \n\t" +#ifdef __ARMEB__ + "adcs %0, %0, %3 \n\t" +#else + "adcs %0, %0, %3, ror #8 \n\t" +#endif + "adc %0, %0, #0" + : "=&r" (sum) + : "r" (daddr), "r" (saddr), "r" (lenprot) + : "cc"); + } else { + __asm__( + "adds %0, %1, %2 @ csum_tcpudp_nofold \n\t" + "adcs %0, %0, %3 \n\t" +#ifdef __ARMEB__ + "adcs %0, %0, %4 \n\t" +#else + "adcs %0, %0, %4, ror #8 \n\t" +#endif + "adc %0, %0, #0" + : "=&r"(sum) + : "r" (sum), "r" (daddr), "r" (saddr), "r" (lenprot) + : "cc"); + } + return sum; +} +/* + * computes the checksum of the TCP/UDP pseudo-header + * returns a 16-bit checksum, already complemented + */ +static inline __sum16 +csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len, + __u8 proto, __wsum sum) +{ + return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); +} + + +/* + * this routine is used for miscellaneous IP-like checksums, mainly + * in icmp.c + */ +static inline __sum16 +ip_compute_csum(const void *buff, int len) +{ + return csum_fold(csum_partial(buff, len, 0)); +} + +#define _HAVE_ARCH_IPV6_CSUM +extern __wsum +__csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr, __be32 len, + __be32 proto, __wsum sum); + +static inline __sum16 +csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr, + __u32 len, __u8 proto, __wsum sum) +{ + return csum_fold(__csum_ipv6_magic(saddr, daddr, htonl(len), + htonl(proto), sum)); +} +#endif |