On Sat, Feb 17, 2024 at 04:07:20PM +0100, Laurent Vivier wrote: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(a)redhat.com>Reviewed-by: David Gibson <david(a)gibson.dropbear.id.au>--- Notes: v3: - update comments - use size_t for the IO vectors length - include checksum.h in checksum.c - export csum_unfolded() (for later) v2: - fix typo and superfluous space - update comments checksum.c | 56 ++++++++++++++++++++++++++++++++++++++++++------------ checksum.h | 2 ++ 2 files changed, 46 insertions(+), 12 deletions(-) diff --git a/checksum.c b/checksum.c index 65486b4625ba..74e3742bc6f6 100644 --- a/checksum.c +++ b/checksum.c @@ -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 @@ -385,16 +386,16 @@ 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 +409,30 @@ 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 + */ +__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 +440,24 @@ 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 + */ +uint16_t csum_iov(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); +} diff --git a/checksum.h b/checksum.h index 21c0310d3804..dfa705a04a24 100644 --- a/checksum.h +++ b/checksum.h @@ -24,6 +24,8 @@ void csum_udp6(struct udphdr *udp6hr, 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(struct iovec *iov, size_t n, uint32_t init); #endif /* CHECKSUM_H */-- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson