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1275 |
phoenix |
/* Copyright 2002,2003 Andi Kleen, SuSE Labs.
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* Subject to the GNU Public License v.2
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*
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* Wrappers of assembly checksum functions for x86-64.
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*/
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#include <asm/checksum.h>
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#include <linux/module.h>
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/**
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* csum_partial_copy_from_user - Copy and checksum from user space.
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* @src: source address (user space)
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* @dst: destination address
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* @len: number of bytes to be copied.
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* @isum: initial sum that is added into the result (32bit unfolded)
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* @errp: set to -EFAULT for an bad source address.
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*
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* Returns an 32bit unfolded checksum of the buffer.
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* src and dst are best aligned to 64bits.
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*/
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unsigned int
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csum_partial_copy_from_user(const char *src, char *dst,
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int len, unsigned int isum, int *errp)
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{
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*errp = 0;
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if (likely(access_ok(VERIFY_READ,src, len))) {
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/* Why 6, not 7? To handle odd addresses aligned we
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would need to do considerable complications to fix the
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checksum which is defined as an 16bit accumulator. The
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fix alignment code is primarily for performance
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compatibility with 32bit and that will handle odd
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addresses slowly too. */
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if (unlikely((unsigned long)src & 6)) {
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while (((unsigned long)src & 6) && len >= 2) {
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__u16 val16;
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*errp = __get_user(val16, (__u16 *)src);
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if (*errp)
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return isum;
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*(__u16 *)dst = val16;
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isum = add32_with_carry(isum, val16);
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src += 2;
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dst += 2;
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len -= 2;
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}
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}
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isum = csum_partial_copy_generic(src,dst,len,isum,errp,NULL);
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if (likely(*errp == 0))
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return isum;
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}
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*errp = -EFAULT;
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memset(dst,0,len);
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return isum;
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}
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EXPORT_SYMBOL(csum_partial_copy_from_user);
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/**
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* csum_partial_copy_to_user - Copy and checksum to user space.
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* @src: source address
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* @dst: destination address (user space)
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* @len: number of bytes to be copied.
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* @isum: initial sum that is added into the result (32bit unfolded)
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* @errp: set to -EFAULT for an bad destination address.
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*
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* Returns an 32bit unfolded checksum of the buffer.
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* src and dst are best aligned to 64bits.
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*/
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unsigned int
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csum_partial_copy_to_user(const char *src, char *dst,
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int len, unsigned int isum, int *errp)
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{
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if (unlikely(!access_ok(VERIFY_WRITE, dst, len))) {
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*errp = -EFAULT;
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return 0;
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}
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if (unlikely((unsigned long)dst & 6)) {
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while (((unsigned long)dst & 6) && len >= 2) {
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__u16 val16 = *(__u16 *)src;
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isum = add32_with_carry(isum, val16);
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*errp = __put_user(val16, (__u16 *)dst);
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if (*errp)
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return isum;
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src += 2;
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dst += 2;
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len -= 2;
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}
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}
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*errp = 0;
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return csum_partial_copy_generic(src,dst,len,isum,NULL,errp);
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}
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EXPORT_SYMBOL(csum_partial_copy_to_user);
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/**
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* csum_partial_copy_nocheck - Copy and checksum.
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* @src: source address
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* @dst: destination address
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* @len: number of bytes to be copied.
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* @isum: initial sum that is added into the result (32bit unfolded)
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*
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* Returns an 32bit unfolded checksum of the buffer.
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*/
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unsigned int
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csum_partial_copy_nocheck(const char *src, char *dst, int len, unsigned int sum)
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{
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return csum_partial_copy_generic(src,dst,len,sum,NULL,NULL);
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}
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unsigned short csum_ipv6_magic(struct in6_addr *saddr, struct in6_addr *daddr,
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__u32 len, unsigned short proto, unsigned int sum)
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{
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__u64 rest, sum64;
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rest = (__u64)htonl(len) + (__u64)htons(proto) + (__u64)sum;
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asm(" addq (%[saddr]),%[sum]\n"
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" adcq 8(%[saddr]),%[sum]\n"
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" adcq (%[daddr]),%[sum]\n"
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" adcq 8(%[daddr]),%[sum]\n"
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" adcq $0,%[sum]\n"
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: [sum] "=r" (sum64)
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: "[sum]" (rest),[saddr] "r" (saddr), [daddr] "r" (daddr));
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return csum_fold(add32_with_carry(sum64 & 0xffffffff, sum64>>32));
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}
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EXPORT_SYMBOL(csum_ipv6_magic);
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