Re: [dpdk-dev] [RFC] app/testpmd: add generic swap forwarding engine

[Kevin Traynor <ktraynor@redhat.com>]

On 15/04/2020 14:48, Xiaoyu Min wrote:
> This RFC propose a generic `swap` forwarding engine, which could be seen
> as an extension of existing `macswap` but provide more flexibility.
> 
> With this generic `swap` forwarding engine, we can `swap` the source and
> destination of L2/L3 address as well as the source and destination port
> of L4 according to the user inputs.
> 
> This will be very helpful for developer/tester in some test scenarios.
> For example, connection tracking functinality in OVS, which needs to
> swap UDP ports in addition to L2/L3 addresses in order to complete one
> connection.
> 
> Signed-off-by: Xiaoyu Min <jackmin@mellanox.com>
> ---
>  app/test-pmd/parameters.c                   |  2 ++
>  doc/guides/testpmd_app_ug/testpmd_funcs.rst | 15 ++++++++++++++-
>  2 files changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/app/test-pmd/parameters.c b/app/test-pmd/parameters.c
> index 404dba2b20..5c9aecd6cb 100644
> --- a/app/test-pmd/parameters.c
> +++ b/app/test-pmd/parameters.c
> @@ -147,6 +147,8 @@ usage(char* progname)
>  	       "is default).\n");
>  	printf("  --forward-mode=N: set forwarding mode (N: %s).\n",
>  	       list_pkt_forwarding_modes());
> +	printf("  --forward-mode=swap[:TYPE[,TYPE]]: set forwarding mode to swap "
> +	       "(TYPE: auto (default) or mac or ip or tp).\n");
>  	printf("  --rss-ip: set RSS functions to IPv4/IPv6 only .\n");
>  	printf("  --rss-udp: set RSS functions to IPv4/IPv6 + UDP.\n");
>  	printf("  --rxq=N: set the number of RX queues per port to N.\n");
> diff --git a/doc/guides/testpmd_app_ug/testpmd_funcs.rst b/doc/guides/testpmd_app_ug/testpmd_funcs.rst
> index dcee5de455..27f0600493 100644
> --- a/doc/guides/testpmd_app_ug/testpmd_funcs.rst
> +++ b/doc/guides/testpmd_app_ug/testpmd_funcs.rst
> @@ -298,7 +298,7 @@ set fwd
>  Set the packet forwarding mode::
>  
>     testpmd> set fwd (io|mac|macswap|flowgen| \
> -                     rxonly|txonly|csum|icmpecho|noisy) (""|retry)
> +                     rxonly|txonly|csum|icmpecho|noisy|swap) (""|retry)
>  
>  ``retry`` can be specified for forwarding engines except ``rx_only``.
>  
> @@ -336,6 +336,19 @@ The available information categories are:
>    Simulate more realistic behavior of a guest machine engaged in receiving
>    and sending packets performing Virtual Network Function (VNF).
>  
> +* ``swap[:TYPE[,TYPE]*]``: Generic swap forwarding mode.
> + 
> +  Swap the source and destination address or/and source and destination port of packet according to ``TYPE`` before forwarding them.
> +  ``TYPE`` could be:
> +
> +  - ``auto``: swaps all supported fields (L2 to L4) if available, default.

It's not an intuitive name and doesn't seem like it's really needed.
Selecting multiple items below is more explicit IMHO.

> + 
> +  - ``mac``: swaps the source address and destination address of Ethernet, as same as ``macswap``.
> + 
> +  - ``ip``: swaps the source address and destination address of IP (v4 and v6).
> + 
> +  - ``tp``: swaps the source port and destination port of transport layer (TCP and UDP).

I think 'port' would be clearer.

> +
>  Example::
>  
>     testpmd> set fwd rxonly
>