[ovs-discuss] regarding trunc feature changes for OVS_ACTION_ATTR_USERSPACE

[Ben Pfaff]

On Tue, Nov 12, 2019 at 01:36:09PM +0530, bindiya Kurle wrote:
> Hi ,
> i am not getting reason,why highlighted code is added for
> OVS_ACTION_ATTR_USERSPACE.
> What purpose it serves.
> This code got added as part of feature "    ofp-actions: Add truncate
> action. The patch adds a new action to support packet truncation. "
> 
> Can somebody please help in understanding below part?
> 
>      file :"lib/dpif-netdev.c"
> function : dp_execute_cb
> 
> case OVS_ACTION_ATTR_USERSPACE:
>        .
> .
> .
> 
>             userdata = nl_attr_find_nested(a, OVS_USERSPACE_ATTR_USERDATA);
>             ofpbuf_init(&actions, 0);
> 
> 
> 
> 
> 
> 
> 
> 
> 
> * if (packets_->trunc) {                if (!should_steal) {
>     dp_packet_batch_clone(&usr_pkt, packets_);                    packets_
> = &usr_pkt;                    clone = true;
> dp_packet_batch_reset_cutlen(orig_packets_);                }
>   dp_packet_batch_apply_cutlen(packets_);*
>             }

I believe that this code truncates the packets.