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checksum: Add an offset argument in csum_iov()

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The offset allows any headers that are not part of the data
to checksum to be skipped.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
Laurent Vivier 2024-10-03 16:51:06 +02:00 committed by Stefano Brivio
parent fd8334b25d
commit e6548c6437
2 changed files with 16 additions and 3 deletions
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16
checksum.c
View file

@ -59,6 +59,7 @@
#include "util.h"
#include "ip.h"
#include "checksum.h"
#include "iov.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
@ -497,16 +498,27 @@ uint16_t csum(const void *buf, size_t len, uint32_t init)
*
* @iov Pointer to the array of IO vectors
* @n Length of the array
* @offset: Offset of the data to checksum within the full data length
* @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)
uint16_t csum_iov(const struct iovec *iov, size_t n, size_t offset,
uint32_t init)
{
unsigned int i;
size_t first;
for (i = 0; i < n; i++)
i = iov_skip_bytes(iov, n, offset, &first);
if (i >= n)
return (uint16_t)~csum_fold(init);
init = csum_unfolded((char *)iov[i].iov_base + first,
iov[i].iov_len - first, init);
i++;
for (; i < n; i++)
init = csum_unfolded(iov[i].iov_base, iov[i].iov_len, init);
return (uint16_t)~csum_fold(init);

3
checksum.h
View file

@ -32,6 +32,7 @@ void csum_icmp6(struct icmp6hdr *icmp6hr,
const void *payload, size_t dlen);
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);
uint16_t csum_iov(const struct iovec *iov, size_t n, size_t offset,
uint32_t init);
#endif /* CHECKSUM_H */