On Tue, Sep 24, 2024 at 05:46:41PM +0200, Laurent Vivier wrote:The offset allows any headers are that are not part of the data to checksum to be skipped. Signed-off-by: Laurent Vivier <lvivier(a)redhat.com> --- checksum.c | 13 +++++++++++-- checksum.h | 3 ++- 2 files changed, 13 insertions(+), 3 deletions(-) diff --git a/checksum.c b/checksum.c index 006614fcbb28..f80db4d309a2 100644 --- a/checksum.c +++ b/checksum.c @@ -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 @@ -498,15 +499,23 @@ 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 * @init Initial 32-bit checksum, 0 for no pre-computed checksum + * @offset: Offset of the data to checksum within the full data length * * 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);Just to be safe, you should probably check for i >= n here: if offset is larger than the total length of the vector enough, iov_skip_bytes() will return that.+ init = csum_unfolded((char *)iov[i].iov_base + first, + iov[i].iov_len, init); + i++; + + for (; 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 c5964ac78921..49f7472dd1b6 100644 --- a/checksum.h +++ b/checksum.h @@ -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 */-- David Gibson (he or they) | 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