Re: [dpdk-dev] [PATCH v4 4/4] app/testpmd: match GRE's key and present bits

[Adrien Mazarguil <adrien.mazarguil@6wind.com>]

On Tue, Jul 02, 2019 at 05:45:55PM +0800, Xiaoyu Min wrote:
> support matching on GRE key and present bits (C,K,S)
> 
> example testpmd command could be:
>   testpmd>flow create 0 ingress group 1 pattern eth / ipv4 /
>           gre crksv is 0x2000 crksv mask 0xb000 /
> 	  gre_key key is 0x12345678 / end
> 	  actions rss queues 1 0 end / mark id 196 / end
> 
> Which will match GRE packet with k present bit set and key value is
> 0x12345678.
> 
> Signed-off-by: Xiaoyu Min <jackmin@mellanox.com>

I'm wondering... Is matching the K bit mandatory if one explicitly matches
gre_key already or is this a specific hardware limitation in your case?

Perhaps we could document that the K bit is implicitly matched as "1" in the
default mask when a gre_key pattern item is present. If a user explicitly
spec/mask K as "0" and still provides gre_key, the PMD can safely ignore the
gre_key item.

I'm asking because I think most users won't bother with the K bit when
attempting to match some key and their rules may not behave as expected as a
result.

More below.

> ---
> ** This patch is based on patch [1]
> 
> [1] https://patches.dpdk.org/patch/55773/
> ---
>  app/test-pmd/cmdline_flow.c                 | 32 +++++++++++++++++++++
>  doc/guides/testpmd_app_ug/testpmd_funcs.rst |  4 +++
>  2 files changed, 36 insertions(+)
> 
> diff --git a/app/test-pmd/cmdline_flow.c b/app/test-pmd/cmdline_flow.c
> index 201bd9de56..8504cc8bc1 100644
> --- a/app/test-pmd/cmdline_flow.c
> +++ b/app/test-pmd/cmdline_flow.c
> @@ -148,6 +148,9 @@ enum index {
>  	ITEM_MPLS_LABEL,
>  	ITEM_GRE,
>  	ITEM_GRE_PROTO,
> +	ITEM_GRE_CRKSV,
> +	ITEM_GRE_KEY,
> +	ITEM_GRE_KEY_KEY,

Assuming you move the GRE_KEY definition in rte_flow.h, please keep its
location synchronized in this list as well.

>  	ITEM_FUZZY,
>  	ITEM_FUZZY_THRESH,
>  	ITEM_GTP,
> @@ -595,6 +598,7 @@ static const enum index next_item[] = {
>  	ITEM_NVGRE,
>  	ITEM_MPLS,
>  	ITEM_GRE,
> +	ITEM_GRE_KEY,
>  	ITEM_FUZZY,
>  	ITEM_GTP,
>  	ITEM_GTPC,
> @@ -755,6 +759,13 @@ static const enum index item_mpls[] = {
>  
>  static const enum index item_gre[] = {
>  	ITEM_GRE_PROTO,
> +	ITEM_GRE_CRKSV,

CRKSV may be unnecessary in this patch if the K bit is documented and
implemented as described in my previous comment.

> +	ITEM_NEXT,
> +	ZERO,
> +};
> +
> +static const enum index item_gre_key[] = {
> +	ITEM_GRE_KEY_KEY,
>  	ITEM_NEXT,
>  	ZERO,
>  };
> @@ -1898,6 +1909,27 @@ static const struct token token_list[] = {
>  		.args = ARGS(ARGS_ENTRY_HTON(struct rte_flow_item_gre,
>  					     protocol)),
>  	},
> +	[ITEM_GRE_CRKSV] = {
> +		.name = "crksv",
> +		.help = "GRE's first word (bit0 - bit15)",
> +		.next = NEXT(item_gre, NEXT_ENTRY(UNSIGNED), item_param),
> +		.args = ARGS(ARGS_ENTRY_HTON(struct rte_flow_item_gre,
> +					     c_rsvd0_ver)),
> +	},
> +	[ITEM_GRE_KEY] = {
> +		.name = "gre_key",
> +		.help = "match GRE Key",
> +		.priv = PRIV_ITEM(GRE_KEY,
> +				  sizeof(rte_be32_t)),

Could be a single line.

> +		.next = NEXT(item_gre_key),
> +		.call = parse_vc,
> +	},
> +	[ITEM_GRE_KEY_KEY] = {
> +		.name = "key",
> +		.help = "GRE key",
> +		.next = NEXT(item_gre_key, NEXT_ENTRY(UNSIGNED), item_param),
> +		.args = ARGS(ARG_ENTRY_HTON(rte_be32_t)),
> +	},
>  	[ITEM_FUZZY] = {
>  		.name = "fuzzy",
>  		.help = "fuzzy pattern match, expect faster than default",
> diff --git a/doc/guides/testpmd_app_ug/testpmd_funcs.rst b/doc/guides/testpmd_app_ug/testpmd_funcs.rst
> index cb83a3ce8a..fc3ba8a009 100644
> --- a/doc/guides/testpmd_app_ug/testpmd_funcs.rst
> +++ b/doc/guides/testpmd_app_ug/testpmd_funcs.rst
> @@ -3804,6 +3804,10 @@ This section lists supported pattern items and their attributes, if any.
>  
>    - ``protocol {unsigned}``: protocol type.
>  
> +- ``gre_key``: match GRE optional key field.
> +
> +  - ``key {unsigned}``: key value.
> +

You should have named this field "value" then, i.e.:

 - ``value {unsigned}``: key value.

>  - ``fuzzy``: fuzzy pattern match, expect faster than default.
>  
>    - ``thresh {unsigned}``: accuracy threshold.
> -- 
> 2.21.0
> 

-- 
Adrien Mazarguil
6WIND