On Mon, Nov 11, 2024 at 11:43 AM Dumitru Ceara <dce...@redhat.com> wrote:

> The actions that retrieve the original tuple destination IPs and ports
> were used in the following way in ovn-northd:
>
>   REG_ORIG_DIP_IPV4 " = ct_nw_dst()
>   REG_ORIG_DIP_IPV6 " = ct_ip6_dst()
>   REG_ORIG_TP_DPORT " = ct_tp_dst()
>
> Where:
>   REG_ORIG_DIP_IPV4 is reg1
>   REG_ORIG_DIP_IPV6 is xxreg1
>   REG_ORIG_TP_DPORT is reg2[0..15]
>
> While the actions use a different intermediate register:
>   ct_nw_dst()  was reg4<-0; reg4<-ct_nw_dst
>   ct_ip6_dst() was xxreg0<-0; xxreg0<-ct_ip6_dst
>   ct_tp_dst()  was reg8[0..15]<-0; reg8[0..15]<-ct_tp_dst
>
> We can reduce the set of registers we use in the OVN pipeline by
> changing the action definition to use the same registers ovn-northd uses
> as final destination for the ct_*_dst() values.  This will generate the
> following openflow rules:
>
>   REG_ORIG_DIP_IPV4 " = ct_nw_dst()
>     reg1<-0; reg1<-ct_nw_dst; reg1<-reg1
>   REG_ORIG_DIP_IPV6 " = ct_ip6_dst()
>     xxreg1<-0; xxreg1<-ct_ip6_dst; xxreg1<-xxreg1
>   REG_ORIG_TP_DPORT " = ct_tp_dst()
>     reg2[0..15]<-0; reg2[0..15]<-ct_tp_dst; reg2[0..15]<-reg2[0..15]
>
> As Ilya Maximets points out, overlapping source and destination are
> well defined for move actions:
>
> https://opennetworking.org/wp-content/uploads/2014/10/openflow-switch-v1.5.0.noipr.pdf
>
>   This action must behaves properly when src_oxm_id overlaps with
>   dst_oxm_id, that is, it behaves as if src_oxm_id were copied out
>   to a temporary buffer, then the temporary buffer copied to
>   dst_oxm_id, if this is not possible the switch must reject the
>   Copy Field action with a Bad Set Type error message.
>
> OpenvSwitch doesn't reject such actions.
>
> Fixes: 0f806cf08c36 ("Fix load balanced hairpin traffic for fragmented
> packets.")
> Signed-off-by: Dumitru Ceara <dce...@redhat.com>
> ---
>  include/ovn/logical-fields.h | 7 ++++---
>  tests/ovn.at                 | 8 ++++----
>  2 files changed, 8 insertions(+), 7 deletions(-)
>
> diff --git a/include/ovn/logical-fields.h b/include/ovn/logical-fields.h
> index d563e044cb..70c6b93c41 100644
> --- a/include/ovn/logical-fields.h
> +++ b/include/ovn/logical-fields.h
> @@ -60,9 +60,10 @@ enum ovn_controller_event {
>  #define MFF_LOG_LB_AFF_MATCH_LR_IP6_ADDR    MFF_XXREG1
>  #define MFF_LOG_LB_AFF_MATCH_PORT           MFF_REG8
>
> -#define MFF_LOG_CT_ORIG_NW_DST_ADDR         MFF_REG4
> -#define MFF_LOG_CT_ORIG_IP6_DST_ADDR        MFF_XXREG0
> -#define MFF_LOG_CT_ORIG_TP_DST_PORT         MFF_REG8
> +#define MFF_LOG_CT_ORIG_NW_DST_ADDR         MFF_REG1   /*
> REG_ORIG_DIP_IPV4 */
> +#define MFF_LOG_CT_ORIG_IP6_DST_ADDR        MFF_XXREG1 /*
> REG_ORIG_DIP_IPV6 */
> +#define MFF_LOG_CT_ORIG_TP_DST_PORT         MFF_REG2   /*
> REG_ORIG_TP_DPORT
> +                                                        * (bits 0..15). */
>
>  void ovn_init_symtab(struct shash *symtab);
>
> diff --git a/tests/ovn.at b/tests/ovn.at
> index 15b78f4c37..03fd2090fc 100644
> --- a/tests/ovn.at
> +++ b/tests/ovn.at
> @@ -2420,10 +2420,10 @@ mac_cache_use;
>
>  # ct_nw_dst()
>  reg1 = ct_nw_dst();
> -    encodes as
> set_field:0->reg4,resubmit(,OFTABLE_CT_ORIG_NW_DST_LOAD),move:NXM_NX_REG4[[]]->NXM_NX_XXREG0[[64..95]]
> +    encodes as
> set_field:0->reg1,resubmit(,OFTABLE_CT_ORIG_NW_DST_LOAD),move:NXM_NX_REG1[[]]->NXM_NX_XXREG0[[64..95]]
>
>  xreg1[[3..34]] = ct_nw_dst();
> -    encodes as
> set_field:0->reg4,resubmit(,OFTABLE_CT_ORIG_NW_DST_LOAD),move:NXM_NX_REG4[[]]->NXM_NX_XXREG0[[3..34]]
> +    encodes as
> set_field:0->reg1,resubmit(,OFTABLE_CT_ORIG_NW_DST_LOAD),move:NXM_NX_REG1[[]]->NXM_NX_XXREG0[[3..34]]
>
>  reg1[[3..34]] = ct_nw_dst();
>      Cannot select bits 3 to 34 of 32-bit field reg1.
> @@ -2442,7 +2442,7 @@ ct_nw_dst();
>
>  # ct_ip6_dst()
>  xxreg1 = ct_ip6_dst();
> -    encodes as
> set_field:0/0xffffffffffffffff->xxreg0,set_field:0/0xffffffffffffffff0000000000000000->xxreg0,resubmit(,OFTABLE_CT_ORIG_IP6_DST_LOAD),move:NXM_NX_XXREG0[[]]->NXM_NX_XXREG1[[]]
> +    encodes as
> set_field:0/0xffffffffffffffff->xxreg1,set_field:0/0xffffffffffffffff0000000000000000->xxreg1,resubmit(,OFTABLE_CT_ORIG_IP6_DST_LOAD),move:NXM_NX_XXREG1[[]]->NXM_NX_XXREG1[[]]
>
>  reg1 = ct_ip6_dst();
>      Cannot use 32-bit field reg1[[0..31]] where 128-bit field is required.
> @@ -2455,7 +2455,7 @@ ct_ip6_dst();
>
>  # ct_tp_dst()
>  reg1[[0..15]] = ct_tp_dst();
> -    encodes as
> set_field:0/0xffff->reg8,resubmit(,OFTABLE_CT_ORIG_TP_DST_LOAD),move:NXM_NX_REG8[[0..15]]->NXM_NX_XXREG0[[64..79]]
> +    encodes as
> set_field:0/0xffff->reg2,resubmit(,OFTABLE_CT_ORIG_TP_DST_LOAD),move:NXM_NX_REG2[[0..15]]->NXM_NX_XXREG0[[64..79]]
>
>  reg1 = ct_tp_dst();
>      Cannot use 32-bit field reg1[[0..31]] where 16-bit field is required.
> --
> 2.46.2
>
> _______________________________________________
> dev mailing list
> d...@openvswitch.org
> https://mail.openvswitch.org/mailman/listinfo/ovs-dev
>
>
Looks good to me, thanks.

Acked-by: Ales Musil <amu...@redhat.com>
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