On 12/19/23 15:47, Mike Pattrick wrote:
> When OVS needs to fallback on the software TSO implementation to segment
> a packet, it currently doesn't guarantee that IP and TCP checksum
> offload flags are set. However, it is possible that these is required.
> This is true in the case of dp_netdev_upcall(), which clears these
> flags.
>
> This patch explicitly sets the appropriate flags when the segmentation
> flag is removed, to guarantee that packets always end up with correct
> checksums.
>
> Signed-off-by: Mike Pattrick <[email protected]>
>
> ---
>
> v3: Moved logic from ofproto-dpif-upcall to dp-packet
> Signed-off-by: Mike Pattrick <[email protected]>
> ---
> lib/dp-packet.h | 16 ++++++++++++++--
> 1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/lib/dp-packet.h b/lib/dp-packet.h
> index 11aa00723..f91b5e3fb 100644
> --- a/lib/dp-packet.h
> +++ b/lib/dp-packet.h
> @@ -1131,11 +1131,23 @@ dp_packet_hwol_set_tcp_seg(struct dp_packet *b)
> *dp_packet_ol_flags_ptr(b) |= DP_PACKET_OL_TX_TCP_SEG;
> }
>
> -/* Resets TCP Segmentation flag in packet 'p'. */
> +/* Resets TCP Segmentation in packet 'p' and adjust flags to indicate
> + * L3 and L4 checksumming is now required. */
> static inline void
> dp_packet_hwol_reset_tcp_seg(struct dp_packet *p)
> {
> - *dp_packet_ol_flags_ptr(p) &= ~DP_PACKET_OL_TX_TCP_SEG;
> + uint64_t ol_flags = *dp_packet_ol_flags_ptr(p)
> + | DP_PACKET_OL_TX_TCP_CKSUM;
> +
> + ol_flags = ol_flags & ~(DP_PACKET_OL_TX_TCP_SEG
> + | DP_PACKET_OL_RX_L4_CKSUM_MASK
> + | DP_PACKET_OL_RX_IP_CKSUM_GOOD);
This is a little unclear why we clear all L4 checksum flags,
but we do not clear IP_CKSUM_BAD. Is there a reason for that?
If so, we should have a comment here explaining the situation
as it is not obvious.
> +
> + if (ol_flags & DP_PACKET_OL_TX_IPV4) {
> + ol_flags |= DP_PACKET_OL_TX_IP_CKSUM;
Nit: Over-indented. One space too far.
> + }
> +
> + *dp_packet_ol_flags_ptr(p) = ol_flags;
> }
>
> /* Returns 'true' if the IP header has good integrity and the
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