254 lines
5.7 KiB
C
254 lines
5.7 KiB
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 1995, 96, 97, 98, 99, 2001 by Ralf Baechle
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* Copyright (C) 1999 Silicon Graphics, Inc.
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* Copyright (C) 2001 Thiemo Seufer.
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* Copyright (C) 2002 Maciej W. Rozycki
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*/
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#ifndef _ASM_CHECKSUM_H
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#define _ASM_CHECKSUM_H
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#include <linux/config.h>
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#include <linux/in6.h>
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#include <asm/uaccess.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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unsigned int csum_partial(const unsigned char *buff, int len, unsigned int sum);
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/*
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* this is a new version of the above that records errors it finds in *errp,
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* but continues and zeros the rest of the buffer.
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*/
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unsigned int csum_partial_copy_from_user(const unsigned char *src, unsigned char *dst, int len,
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unsigned int sum, int *errp);
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/*
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* Copy and checksum to user
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*/
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#define HAVE_CSUM_COPY_USER
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static inline unsigned int csum_and_copy_to_user (const unsigned char *src,
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unsigned char __user *dst,
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int len, int sum,
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int *err_ptr)
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{
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might_sleep();
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sum = csum_partial(src, len, sum);
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if (copy_to_user(dst, src, len)) {
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*err_ptr = -EFAULT;
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return -1;
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}
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return sum;
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}
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/*
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* the same as csum_partial, but copies from user space (but on MIPS
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* we have just one address space, so this is identical to the above)
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*/
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unsigned int csum_partial_copy_nocheck(const unsigned char *src, unsigned char *dst,
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int len, unsigned int sum);
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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 unsigned short int csum_fold(unsigned int sum)
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{
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__asm__(
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".set\tnoat\t\t\t# csum_fold\n\t"
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"sll\t$1,%0,16\n\t"
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"addu\t%0,$1\n\t"
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"sltu\t$1,%0,$1\n\t"
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"srl\t%0,%0,16\n\t"
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"addu\t%0,$1\n\t"
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"xori\t%0,0xffff\n\t"
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".set\tat"
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: "=r" (sum)
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: "0" (sum));
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return sum;
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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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* By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
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* Arnt Gulbrandsen.
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*/
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static inline unsigned short ip_fast_csum(unsigned char *iph, unsigned int ihl)
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{
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unsigned int *word = (unsigned int *) iph;
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unsigned int *stop = word + ihl;
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unsigned int csum;
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int carry;
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csum = word[0];
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csum += word[1];
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carry = (csum < word[1]);
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csum += carry;
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csum += word[2];
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carry = (csum < word[2]);
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csum += carry;
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csum += word[3];
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carry = (csum < word[3]);
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csum += carry;
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word += 4;
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do {
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csum += *word;
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carry = (csum < *word);
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csum += carry;
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word++;
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} while (word != stop);
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return csum_fold(csum);
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}
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static inline unsigned int csum_tcpudp_nofold(unsigned long saddr,
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unsigned long daddr, unsigned short len, unsigned short proto,
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unsigned int sum)
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{
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__asm__(
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".set\tnoat\t\t\t# csum_tcpudp_nofold\n\t"
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#ifdef CONFIG_MIPS32
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"addu\t%0, %2\n\t"
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"sltu\t$1, %0, %2\n\t"
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"addu\t%0, $1\n\t"
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"addu\t%0, %3\n\t"
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"sltu\t$1, %0, %3\n\t"
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"addu\t%0, $1\n\t"
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"addu\t%0, %4\n\t"
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"sltu\t$1, %0, %4\n\t"
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"addu\t%0, $1\n\t"
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#endif
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#ifdef CONFIG_MIPS64
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"daddu\t%0, %2\n\t"
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"daddu\t%0, %3\n\t"
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"daddu\t%0, %4\n\t"
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"dsll32\t$1, %0, 0\n\t"
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"daddu\t%0, $1\n\t"
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"dsrl32\t%0, %0, 0\n\t"
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#endif
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".set\tat"
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: "=r" (sum)
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: "0" (daddr), "r"(saddr),
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#ifdef __MIPSEL__
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"r" (((unsigned long)htons(len)<<16) + proto*256),
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#else
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"r" (((unsigned long)(proto)<<16) + len),
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#endif
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"r" (sum));
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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 unsigned short int csum_tcpudp_magic(unsigned long saddr,
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unsigned long daddr,
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unsigned short len,
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unsigned short proto,
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unsigned int 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 unsigned short ip_compute_csum(unsigned char * 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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static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
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struct in6_addr *daddr,
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__u32 len,
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unsigned short proto,
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unsigned int sum)
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{
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__asm__(
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".set\tpush\t\t\t# csum_ipv6_magic\n\t"
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".set\tnoreorder\n\t"
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".set\tnoat\n\t"
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"addu\t%0, %5\t\t\t# proto (long in network byte order)\n\t"
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"sltu\t$1, %0, %5\n\t"
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"addu\t%0, $1\n\t"
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"addu\t%0, %6\t\t\t# csum\n\t"
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"sltu\t$1, %0, %6\n\t"
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"lw\t%1, 0(%2)\t\t\t# four words source address\n\t"
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"addu\t%0, $1\n\t"
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"addu\t%0, %1\n\t"
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"sltu\t$1, %0, %1\n\t"
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"lw\t%1, 4(%2)\n\t"
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"addu\t%0, $1\n\t"
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"addu\t%0, %1\n\t"
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"sltu\t$1, %0, %1\n\t"
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"lw\t%1, 8(%2)\n\t"
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"addu\t%0, $1\n\t"
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"addu\t%0, %1\n\t"
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"sltu\t$1, %0, %1\n\t"
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"lw\t%1, 12(%2)\n\t"
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"addu\t%0, $1\n\t"
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"addu\t%0, %1\n\t"
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"sltu\t$1, %0, %1\n\t"
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"lw\t%1, 0(%3)\n\t"
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"addu\t%0, $1\n\t"
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"addu\t%0, %1\n\t"
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"sltu\t$1, %0, %1\n\t"
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"lw\t%1, 4(%3)\n\t"
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"addu\t%0, $1\n\t"
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"addu\t%0, %1\n\t"
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"sltu\t$1, %0, %1\n\t"
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"lw\t%1, 8(%3)\n\t"
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"addu\t%0, $1\n\t"
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"addu\t%0, %1\n\t"
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"sltu\t$1, %0, %1\n\t"
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"lw\t%1, 12(%3)\n\t"
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"addu\t%0, $1\n\t"
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"addu\t%0, %1\n\t"
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"sltu\t$1, %0, %1\n\t"
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"addu\t%0, $1\t\t\t# Add final carry\n\t"
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".set\tpop"
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: "=r" (sum), "=r" (proto)
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: "r" (saddr), "r" (daddr),
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"0" (htonl(len)), "1" (htonl(proto)), "r" (sum));
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return csum_fold(sum);
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}
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#endif /* _ASM_CHECKSUM_H */
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