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:
v4:
- rebase
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 */
--
2.42.0