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01cfbad79a
This patch updates all instances of csum_tcpudp_magic and csum_tcpudp_nofold to reflect the types that are usually used as the source inputs. For example the protocol field is populated based on nexthdr which is actually an unsigned 8 bit value. The length is usually populated based on skb->len which is an unsigned integer. This addresses an issue in which the IPv6 function csum_ipv6_magic was generating a checksum using the full 32b of skb->len while csum_tcpudp_magic was only using the lower 16 bits. As a result we could run into issues when attempting to adjust the checksum as there was no protocol agnostic way to update it. With this change the value is still truncated as many architectures use "(len + proto) << 8", however this truncation only occurs for values greater than 16776960 in length and as such is unlikely to occur as we stop the inner headers at ~64K in size. I did have to make a few minor changes in the arm, mn10300, nios2, and score versions of the function in order to support these changes as they were either using things such as an OR to combine the protocol and length, or were using ntohs to convert the length which would have truncated the value. I also updated a few spots in terms of whitespace and type differences for the addresses. Most of this was just to make sure all of the definitions were in sync going forward. Signed-off-by: Alexander Duyck <aduyck@mirantis.com> Signed-off-by: David S. Miller <davem@davemloft.net>
155 lines
3.7 KiB
C
155 lines
3.7 KiB
C
#ifndef __UM_CHECKSUM_H
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#define __UM_CHECKSUM_H
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#include <linux/string.h>
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#include <linux/in6.h>
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#include <linux/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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extern __wsum csum_partial(const void *buff, int len, __wsum sum);
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/*
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* Note: when you get a NULL pointer exception here this means someone
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* passed in an incorrect kernel address to one of these functions.
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*
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* If you use these functions directly please don't forget the
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* access_ok().
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*/
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static __inline__
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__wsum csum_partial_copy_nocheck(const void *src, void *dst,
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int len, __wsum sum)
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{
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memcpy(dst, src, len);
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return csum_partial(dst, len, sum);
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}
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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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static __inline__
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__wsum csum_partial_copy_from_user(const void __user *src, void *dst,
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int len, __wsum sum, int *err_ptr)
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{
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if (copy_from_user(dst, src, len)) {
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*err_ptr = -EFAULT;
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return (__force __wsum)-1;
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}
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return csum_partial(dst, len, sum);
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}
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/**
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* csum_fold - Fold and invert a 32bit checksum.
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* sum: 32bit unfolded sum
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*
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* Fold a 32bit running checksum to 16bit and invert it. This is usually
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* the last step before putting a checksum into a packet.
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* Make sure not to mix with 64bit checksums.
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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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" addl %1,%0\n"
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" adcl $0xffff,%0"
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: "=r" (sum)
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: "r" ((__force u32)sum << 16),
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"0" ((__force u32)sum & 0xffff0000)
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);
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return (__force __sum16)(~(__force u32)sum >> 16);
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}
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/**
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* csum_tcpup_nofold - Compute an IPv4 pseudo header checksum.
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* @saddr: source address
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* @daddr: destination address
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* @len: length of packet
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* @proto: ip protocol of packet
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* @sum: initial sum to be added in (32bit unfolded)
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*
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* Returns the pseudo header checksum the input data. Result is
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* 32bit unfolded.
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*/
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static inline __wsum
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csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
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__u8 proto, __wsum sum)
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{
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asm(" addl %1, %0\n"
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" adcl %2, %0\n"
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" adcl %3, %0\n"
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" adcl $0, %0\n"
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: "=r" (sum)
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: "g" (daddr), "g" (saddr), "g" ((len + proto) << 8), "0" (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 __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
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__u32 len, __u8 proto,
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__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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* ip_fast_csum - Compute the IPv4 header checksum efficiently.
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* iph: ipv4 header
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* ihl: length of header / 4
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*/
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static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
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{
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unsigned int sum;
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asm( " movl (%1), %0\n"
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" subl $4, %2\n"
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" jbe 2f\n"
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" addl 4(%1), %0\n"
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" adcl 8(%1), %0\n"
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" adcl 12(%1), %0\n"
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"1: adcl 16(%1), %0\n"
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" lea 4(%1), %1\n"
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" decl %2\n"
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" jne 1b\n"
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" adcl $0, %0\n"
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" movl %0, %2\n"
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" shrl $16, %0\n"
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" addw %w2, %w0\n"
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" adcl $0, %0\n"
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" notl %0\n"
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"2:"
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/* Since the input registers which are loaded with iph and ipl
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are modified, we must also specify them as outputs, or gcc
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will assume they contain their original values. */
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: "=r" (sum), "=r" (iph), "=r" (ihl)
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: "1" (iph), "2" (ihl)
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: "memory");
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return (__force __sum16)sum;
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}
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#ifdef CONFIG_X86_32
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# include "checksum_32.h"
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#else
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# include "checksum_64.h"
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#endif
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#endif
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