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![Ralf Baechle](/assets/img/avatar_default.png)
to it in an asm() block, and we're running on a system with 64-bit registers, it is vitally important that we sign extend it correctly before returning to C. Otherwise the stray high bits will be preserved into csum_fold, and on the SB-1 processor, 32-bit arithmetic on a non sign-extended register will yield surprising results. This caused incorrect checksums in some UDP packets for NFS root. The problem was mild when using a 10.0.1.x IP address, but severe when using 192.168.1.x. Signed-off-by: Daniel Jacobowitz <dan@codesourcery.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
256 lines
5.6 KiB
C
256 lines
5.6 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 __user *src,
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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 push # csum_fold\n"
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" .set noat \n"
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" sll $1, %0, 16 \n"
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" addu %0, $1 \n"
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" sltu $1, %0, $1 \n"
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" srl %0, %0, 16 \n"
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" addu %0, $1 \n"
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" xori %0, 0xffff \n"
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" .set pop"
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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 push # csum_tcpudp_nofold\n"
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" .set noat \n"
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#ifdef CONFIG_32BIT
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" addu %0, %2 \n"
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" sltu $1, %0, %2 \n"
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" addu %0, $1 \n"
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" addu %0, %3 \n"
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" sltu $1, %0, %3 \n"
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" addu %0, $1 \n"
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" addu %0, %4 \n"
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" sltu $1, %0, %4 \n"
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" addu %0, $1 \n"
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#endif
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#ifdef CONFIG_64BIT
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" daddu %0, %2 \n"
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" daddu %0, %3 \n"
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" daddu %0, %4 \n"
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" dsll32 $1, %0, 0 \n"
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" daddu %0, $1 \n"
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" dsra32 %0, %0, 0 \n"
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#endif
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" .set pop"
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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 push # csum_ipv6_magic\n"
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" .set noreorder \n"
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" .set noat \n"
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" addu %0, %5 # proto (long in network byte order)\n"
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" sltu $1, %0, %5 \n"
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" addu %0, $1 \n"
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" addu %0, %6 # csum\n"
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" sltu $1, %0, %6 \n"
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" lw %1, 0(%2) # four words source address\n"
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" addu %0, $1 \n"
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" addu %0, %1 \n"
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" sltu $1, %0, %1 \n"
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" lw %1, 4(%2) \n"
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" addu %0, $1 \n"
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" addu %0, %1 \n"
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" sltu $1, %0, %1 \n"
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" lw %1, 8(%2) \n"
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" addu %0, $1 \n"
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" addu %0, %1 \n"
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" sltu $1, %0, %1 \n"
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" lw %1, 12(%2) \n"
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" addu %0, $1 \n"
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" addu %0, %1 \n"
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" sltu $1, %0, %1 \n"
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" lw %1, 0(%3) \n"
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" addu %0, $1 \n"
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" addu %0, %1 \n"
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" sltu $1, %0, %1 \n"
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" lw %1, 4(%3) \n"
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" addu %0, $1 \n"
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" addu %0, %1 \n"
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" sltu $1, %0, %1 \n"
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" lw %1, 8(%3) \n"
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" addu %0, $1 \n"
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" addu %0, %1 \n"
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" sltu $1, %0, %1 \n"
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" lw %1, 12(%3) \n"
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" addu %0, $1 \n"
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" addu %0, %1 \n"
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" sltu $1, %0, %1 \n"
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" addu %0, $1 # Add final carry\n"
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" .set pop"
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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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