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checksum: add csum_iov()

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Introduce the function csum_unfolded() that computes the unfolded
32-bit checksum of a data buffer, and call it from csum() that returns
the folded value.

Introduce csum_iov() that computes the checksum using csum_folded() on
all vectors of the iovec array and returns the folded result.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Message-ID: <20240303135114.1023026-4-lvivier@redhat.com>
[dwg: Fixed trivial cppcheck & clang-tidy regressions]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
Laurent Vivier 2024-03-06 16:58:32 +11:00 committed by Stefano Brivio
parent 907621eaae
commit e289d287c6
2 changed files with 49 additions and 14 deletions
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59
checksum.c
View file

@ -57,6 +57,7 @@
#include <linux/icmpv6.h>
#include "util.h"
#include "checksum.h"
/* Checksums are optional for UDP over IPv4, so we usually just set
* them to 0. Change this to 1 to calculate real UDP over IPv4
@ -112,8 +113,6 @@ uint16_t csum_fold(uint32_t sum)
return sum;
}
uint16_t csum(const void *buf, size_t len, uint32_t init);
/**
* csum_ip4_header() - Calculate and set IPv4 header checksum
* @ip4h: IPv4 header
@ -385,16 +384,17 @@ less_than_128_bytes:
}
/**
* csum() - Compute TCP/IP-style checksum
* @buf: Input buffer
* @len: Input length
* @init: Initial 32-bit checksum, 0 for no pre-computed checksum
* csum_unfolded - Calculate the unfolded checksum of a data buffer.
*
* Return: 16-bit folded, complemented checksum
* @buf: Input buffer
* @len: Input length
* @init: Initial 32-bit checksum, 0 for no pre-computed checksum
*
* Return: 32-bit unfolded
*/
/* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */
__attribute__((optimize("-fno-strict-aliasing"))) /* See csum_16b() */
uint16_t csum(const void *buf, size_t len, uint32_t init)
uint32_t csum_unfolded(const void *buf, size_t len, uint32_t init)
{
intptr_t align = ROUND_UP((intptr_t)buf, sizeof(__m256i));
unsigned int pad = align - (intptr_t)buf;
@ -408,16 +408,31 @@ uint16_t csum(const void *buf, size_t len, uint32_t init)
if (len > pad)
init = csum_avx2((void *)align, len - pad, init);
return (uint16_t)~csum_fold(init);
return init;
}
#else /* __AVX2__ */
/**
* csum_unfolded - Calculate the unfolded checksum of a data buffer.
*
* @buf: Input buffer
* @len: Input length
* @init: Initial 32-bit checksum, 0 for no pre-computed checksum
*
* Return: 32-bit unfolded checksum
*/
/* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */
__attribute__((optimize("-fno-strict-aliasing"))) /* See csum_16b() */
uint32_t csum_unfolded(const void *buf, size_t len, uint32_t init)
{
return sum_16b(buf, len) + init;
}
#endif /* !__AVX2__ */
/**
* csum() - Compute TCP/IP-style checksum
* @buf: Input buffer
* @len: Input length
* @sum: Initial 32-bit checksum, 0 for no pre-computed checksum
* @init: Initial 32-bit checksum, 0 for no pre-computed checksum
*
* Return: 16-bit folded, complemented checksum
*/
@ -425,7 +440,25 @@ uint16_t csum(const void *buf, size_t len, uint32_t init)
__attribute__((optimize("-fno-strict-aliasing"))) /* See csum_16b() */
uint16_t csum(const void *buf, size_t len, uint32_t init)
{
return (uint16_t)~csum_fold(sum_16b(buf, len) + init);
return (uint16_t)~csum_fold(csum_unfolded(buf, len, init));
}
#endif /* !__AVX2__ */
/**
* csum_iov() - Calculates the unfolded checksum over an array of IO vectors
*
* @iov Pointer to the array of IO vectors
* @n Length of the array
* @init Initial 32-bit checksum, 0 for no pre-computed checksum
*
* Return: 16-bit folded, complemented checksum
*/
/* cppcheck-suppress unusedFunction */
uint16_t csum_iov(const struct iovec *iov, size_t n, uint32_t init)
{
unsigned int i;
for (i = 0; i < n; i++)
init = csum_unfolded(iov[i].iov_base, iov[i].iov_len, init);
return (uint16_t)~csum_fold(init);
}

4
checksum.h
View file

@ -17,13 +17,15 @@ void csum_ip4_header(struct iphdr *ip4h);
void csum_udp4(struct udphdr *udp4hr,
struct in_addr saddr, struct in_addr daddr,
const void *payload, size_t len);
void csum_icmp4(struct icmphdr *ih, const void *payload, size_t len);
void csum_icmp4(struct icmphdr *icmp4hr, const void *payload, size_t len);
void csum_udp6(struct udphdr *udp6hr,
const struct in6_addr *saddr, const struct in6_addr *daddr,
const void *payload, size_t len);
void csum_icmp6(struct icmp6hdr *icmp6hr,
const struct in6_addr *saddr, const struct in6_addr *daddr,
const void *payload, size_t len);
uint32_t csum_unfolded(const void *buf, size_t len, uint32_t init);
uint16_t csum(const void *buf, size_t len, uint32_t init);
uint16_t csum_iov(const struct iovec *iov, size_t n, uint32_t init);
#endif /* CHECKSUM_H */