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

[Jack Min <jackmin@mellanox.com>]

On Wed, 19-07-03, 17:25, Adrien Mazarguil wrote:
> 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?
> 

If there is gre_key item MLX5 PMD will force set HW matching on K bit,
From HW perspective it is mandatory. But, from testpmd (user)
perspective, I agree with you, user needn't set matching on K bit if
they already explicitly set gre_key item.

> 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

Yes, I should document this.
So it should be documented in __testpmd_funcs.rst__ ?

> spec/mask K as "0" and still provides gre_key, the PMD can safely ignore the
> gre_key item.
> 

Well, actullay, when a user explicitly set spec/mask K as "0" and still
provide gre_key item, MLX5 PMD will implicitly set match on K bit as
"1", just ingore the K bit set by user.
The reason is wanna keep code simple, needn't to get
information from other item (gre) inside gre_key item, or vice verse.

And, I think, when a user provides a gre_key item, most probably, they do
really wanna match on gre_key. What do you think?

> 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.
> 

I see.

> More below.
> 
> > ---
> > ** This patch is based on patch [1]
> > 
> > [1] https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatches.dpdk.org%2Fpatch%2F55773%2F&amp;data=02%7C01%7Cjackmin%40mellanox.com%7C590e61b809bb42869cf508d6ffcaa82c%7Ca652971c7d2e4d9ba6a4d149256f461b%7C0%7C0%7C636977643198683579&amp;sdata=LhTsrHRfX3LHhiHRBtz4WKUUklWupJueSBgWmiHPECM%3D&amp;reserved=0
> > ---
> >  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.
> 

I'll do this.

> >  	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.
> 

Well, actully, we also wanna testpmd can match on C,S bits with K bit
together so we can test on gre packet with key only or csum + key, or
csum + key + sequence.

> > +	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.
> 

Yes, I'll update it.

> > +		.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.
> 

OK, I'll update it.

> >  - ``fuzzy``: fuzzy pattern match, expect faster than default.
> >  
> >    - ``thresh {unsigned}``: accuracy threshold.
> > -- 
> > 2.21.0
> > 
> 
> -- 
> Adrien Mazarguil
> 6WIND