Re: [PATCH v6 4/5] tcp: Update TCP checksum using an iovec array

[Laurent Vivier <lvivier@redhat.com>]

On 03/10/2024 16:51, Laurent Vivier wrote:
> TCP header and payload are supposed to be in the same buffer,
> and tcp_update_check_tcp4()/tcp_update_check_tcp6() compute
> the checksum from the base address of the header using the
> length of the IP payload.
> 
> In the future (for vhost-user) we need to dispatch the TCP header and
> the TCP payload through several buffers. To be able to manage that, we
> provide an iovec array that points to the data of the TCP frame.
> We provide also an offset to be able to provide an array that contains
> the TCP frame embedded in an lower level frame, and this offset points
> to the TCP header inside the iovec array.
> 
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> ---
> 
> Notes:
>      v6:
>        - fix clang-tidy error with ptr
>        - add missing static to tcp_update_check_tcp[4|6]
>      
>      v5:
>        - s/IPv6/IPv4/
>        - reintroduce ip6h and iph to avoid iov_size()
>        - check pointer alignment before casting to the type
>      
>      v4:
>        - replace die() by err() in tcp_update_check_tcp6() too
>      
>      v3:
>        - replace die() by err() and return
>        - add more information in the error message
>      
>      v2:
>        - s/payload_offset/l4offset/
>        - check memory address of the checksum (alignment, iovec boundaries)
> 
>   checksum.c |   1 -
>   iov.c      |   1 -
>   tcp.c      | 118 +++++++++++++++++++++++++++++++++++++++++++++--------
>   3 files changed, 100 insertions(+), 20 deletions(-)
> 
...
> diff --git a/iov.c b/iov.c
> index 3f9e229a305f..9116dda94247 100644
> --- a/iov.c
> +++ b/iov.c
> @@ -25,7 +25,6 @@
>   #include "util.h"
>   #include "iov.h"
>   
> -
>   /* iov_skip_bytes() - Skip leading bytes of an IO vector
>    * @iov:	IO vector
>    * @n:		Number of entries in @iov

This is an unwanted change... could you remove it on merge?

Thanks,
Laurent