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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>
101 lines
2.5 KiB
C
101 lines
2.5 KiB
C
/*
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* Network checksum routines
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*
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* Copyright (C) 1999, 2003 Hewlett-Packard Co
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* Stephane Eranian <eranian@hpl.hp.com>
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*
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* Most of the code coming from arch/alpha/lib/checksum.c
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*
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* This file contains network checksum routines that are better done
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* in an architecture-specific manner due to speed..
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*/
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#include <linux/module.h>
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#include <linux/string.h>
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#include <asm/byteorder.h>
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static inline unsigned short
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from64to16 (unsigned long x)
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{
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/* add up 32-bit words for 33 bits */
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x = (x & 0xffffffff) + (x >> 32);
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/* add up 16-bit and 17-bit words for 17+c bits */
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x = (x & 0xffff) + (x >> 16);
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/* add up 16-bit and 2-bit for 16+c bit */
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x = (x & 0xffff) + (x >> 16);
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/* add up carry.. */
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x = (x & 0xffff) + (x >> 16);
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return x;
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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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__sum16
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csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len,
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__u8 proto, __wsum sum)
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{
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return (__force __sum16)~from64to16(
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(__force u64)saddr + (__force u64)daddr +
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(__force u64)sum + ((len + proto) << 8));
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}
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EXPORT_SYMBOL(csum_tcpudp_magic);
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__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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unsigned long result;
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result = (__force u64)saddr + (__force u64)daddr +
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(__force u64)sum + ((len + proto) << 8);
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/* Fold down to 32-bits so we don't lose in the typedef-less network stack. */
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/* 64 to 33 */
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result = (result & 0xffffffff) + (result >> 32);
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/* 33 to 32 */
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result = (result & 0xffffffff) + (result >> 32);
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return (__force __wsum)result;
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}
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EXPORT_SYMBOL(csum_tcpudp_nofold);
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extern unsigned long do_csum (const unsigned char *, long);
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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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u64 result = do_csum(buff, len);
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/* add in old sum, and carry.. */
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result += (__force u32)sum;
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/* 32+c bits -> 32 bits */
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result = (result & 0xffffffff) + (result >> 32);
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return (__force __wsum)result;
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}
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EXPORT_SYMBOL(csum_partial);
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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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__sum16 ip_compute_csum (const void *buff, int len)
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{
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return (__force __sum16)~do_csum(buff,len);
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}
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EXPORT_SYMBOL(ip_compute_csum);
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