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