[dpdk-dev] [PATCH v5 1/2] ethdev: add packet integrity checks

[Gregory Etelson]

Hello Thomas,

Please see my comment on the use of RTE_STD_C11 below.

Regards,
Gregory.

> > > Currently, DPDK application can offload the checksum check, and
> > > report it in the mbuf.
> > >
> > > However, as more and more applications are offloading some or all
> > > logic and action to the HW, there is a need to check the packet
> > > integrity so the right decision can be taken.
> > >
> > > The application logic can be positive meaning if the packet is valid
> > > jump / do  actions, or negative if packet is not valid jump to SW /
> > > do actions (like drop)  a, and add default flow
> >
> > There is a typo here. What should it be?
> >
> Simply remove the a.
> 
> > > (match all in low priority) that will direct the miss packet to the
> > > miss path.
> > >
> > > Since currently rte_flow works in positive way the assumption is
> > > that the positive way will be the common way in this case also.
> > >
> > > When thinking what is the best API to implement such feature, we
> > > need to considure the following (in no specific order):
> >
> > s/considure/consider/
> >
> 
> Will fix.
> 
> > > 1. API breakage.
> > > 2. Simplicity.
> > > 3. Performance.
> > > 4. HW capabilities.
> > > 5. rte_flow limitation.
> > > 6. Flexibility.
> > >
> > > First option: Add integrity flags to each of the items.
> > > For example add checksum_ok to ipv4 item.
> > >
> > > Pros:
> > > 1. No new rte_flow item.
> > > 2. Simple in the way that on each item the app can see what checks
> > > are available.
> > >
> > > Cons:
> > > 1. API breakage.
> > > 2. increase number of flows, since app can't add global rule and
> > >    must have dedicated flow for each of the flow combinations, for
> example
> > >    matching on icmp traffic or UDP/TCP  traffic with IPv4 / IPv6 will
> > >    result in 5 flows.
> > >
> > > Second option: dedicated item
> > >
> > > Pros:
> > > 1. No API breakage, and there will be no for some time due to having
> > >    extra space. (by using bits)
> > > 2. Just one flow to support the icmp or UDP/TCP traffic with IPv4 /
> > >    IPv6.
> > > 3. Simplicity application can just look at one place to see all possible
> > >    checks.
> > > 4. Allow future support for more tests.
> > >
> > > Cons:
> > > 1. New item, that holds number of fields from different items.
> > >
> > > For starter the following bits are suggested:
> > > 1. packet_ok - means that all HW checks depending on packet layer
> have
> > >    passed. This may mean that in some HW such flow should be splited
> to
> > >    number of flows or fail.
> > > 2. l2_ok - all check for layer 2 have passed.
> > > 3. l3_ok - all check for layer 3 have passed. If packet doesn't have
> > >    l3 layer this check should fail.
> > > 4. l4_ok - all check for layer 4 have passed. If packet doesn't
> > >    have l4 layer this check should fail.
> > > 5. l2_crc_ok - the layer 2 crc is O.K.
> > > 6. ipv4_csum_ok - IPv4 checksum is O.K. it is possible that the
> > >    IPv4 checksum will be O.K. but the l3_ok will be 0. it is not
> > >    possible that checksum will be 0 and the l3_ok will be 1.
> > > 7. l4_csum_ok - layer 4 checksum is O.K.
> > > 8. l3_len_OK - check that the reported layer 3 len is smaller than the
> > >    frame len.
> > >
> > > Example of usage:
> > > 1. check packets from all possible layers for integrity.
> > >    flow create integrity spec packet_ok = 1 mask packet_ok = 1 .....
> > >
> > > 2. Check only packet with layer 4 (UDP / TCP)
> > >    flow create integrity spec l3_ok = 1, l4_ok = 1 mask l3_ok = 1
> > > l4_ok = 1
> > >
> > > Signed-off-by: Ori Kam <orika at nvidia.com>
> > > ---
> > >  doc/guides/prog_guide/rte_flow.rst     | 20 +++++++++++
> > >  doc/guides/rel_notes/release_21_05.rst |  5 +++
> > >  lib/librte_ethdev/rte_flow.h           | 49
> ++++++++++++++++++++++++++
> > >  3 files changed, 74 insertions(+)
> > >
> > > diff --git a/doc/guides/prog_guide/rte_flow.rst
> > b/doc/guides/prog_guide/rte_flow.rst
> > > index e1b93ecedf..1dd2301a07 100644
> > > --- a/doc/guides/prog_guide/rte_flow.rst
> > > +++ b/doc/guides/prog_guide/rte_flow.rst
> > > @@ -1398,6 +1398,26 @@ Matches a eCPRI header.
> > >  - ``hdr``: eCPRI header definition (``rte_ecpri.h``).
> > >  - Default ``mask`` matches nothing, for all eCPRI messages.
> > >
> > > +Item: ``PACKET_INTEGRITY_CHECKS``
> > > +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> > > +
> > > +Matches packet integrity.
> > > +For some devices application needs to enable integration checks in
> > > +HW before using this item.
> > > +
> > > +- ``level``: the encapsulation level that should be checked. level
> > > +0 means the
> > > +  default PMD mode (Can be inner most / outermost). value of 1
> > > +means
> > outermost
> > > +  and higher value means inner header. See also RSS level.
> > > +- ``packet_ok``: All HW packet integrity checks have passed based
> > > +on the
> > max
> > > +  layer of the packet.
> > > +- ``l2_ok``: all layer 2 HW integrity checks passed.
> > > +- ``l3_ok``: all layer 3 HW integrity checks passed.
> > > +- ``l4_ok``: all layer 4 HW integrity checks passed.
> > > +- ``l2_crc_ok``: layer 2 crc check passed.
> > > +- ``ipv4_csum_ok``: ipv4 checksum check passed.
> > > +- ``l4_csum_ok``: layer 4 checksum check passed.
> > > +- ``l3_len_ok``: the layer 3 len is smaller than the frame len.
> > > +
> > >  Actions
> > >  ~~~~~~~
> > >
> > > diff --git a/doc/guides/rel_notes/release_21_05.rst
> > b/doc/guides/rel_notes/release_21_05.rst
> > > index a0b907994a..986f749384 100644
> > > --- a/doc/guides/rel_notes/release_21_05.rst
> > > +++ b/doc/guides/rel_notes/release_21_05.rst
> > > @@ -168,6 +168,11 @@ New Features
> > >      the events across multiple stages.
> > >    * This also reduced the scheduling overhead on a event device.
> > >
> > > +* **Added packet integrity match to RTE flow rules.**
> >
> > Please remove "RTE", it has no meaning. All in DPDK is "RTE".
> >
> 
> Sure.
> 
> > > +
> > > +  * Added ``PACKET_INTEGRITY_CHECKS`` flow item.
> >
> > It is RTE_FLOW_ITEM_TYPE_INTEGRITY
> >
> > > +  * Added ``rte_flow_item_integrity`` data structure.
> > > +
> >
> > This text should be sorted before drivers.
> >
> 
> Sure.
> 
> > > --- a/lib/librte_ethdev/rte_flow.h
> > > +++ b/lib/librte_ethdev/rte_flow.h
> > > @@ -551,6 +551,17 @@ enum rte_flow_item_type {
> > >  	 * See struct rte_flow_item_geneve_opt
> > >  	 */
> > >  	RTE_FLOW_ITEM_TYPE_GENEVE_OPT,
> > > +
> > > +	/**
> > > +	 * [META]
> > > +	 *
> > > +	 * Matches on packet integrity.
> > > +	 * For some devices application needs to enable integration checks
> > > +in
> > HW
> > > +	 * before using this item.
> >
> > That's a bit fuzzy.
> > Do you mean some driver-specific API may be required?
> >
> 
> I know it is a bit fuzzy but it is really HW dependent, for example in case of
> some drivers there is nothing to be done.
> In other cases the application may need to enable the RX checksum offload,
> other drivers may need this cap be enabled by HW configuration.
> 
> > > +	 *
> > > +	 * See struct rte_flow_item_integrity.
> > > +	 */
> > > +	RTE_FLOW_ITEM_TYPE_INTEGRITY,
> > >  };
> >
> > > +__extension__
> >
> > Why extension here?
> > If this is because of the anonymous union, it should be RTE_STD_C11
> > before the union.
> > Same for the struct.
> >
> O.K
> 

The RTE_STD_C11 macro fails compilation on 
RHEL-7.9 with gcc version 4.8.5 20150623 (Red Hat 4.8.5-44)

> > > +struct rte_flow_item_integrity {
> > > +	uint32_t level;
> > > +	/**< Packet encapsulation level the item should apply to.
> > > +	 * @see rte_flow_action_rss
> > > +	 */
> >
> > Please insert comments before the struct member.
> >
> O.K.
> 
> > Instead of "Packet encapsulation", isn't it better understood as
> > "Tunnel encapsulation"? Not sure, please advise.
> >
> I have no strong feeling ether way, so I don't mind the change if you think it
> is clearer.
> 
> > > +	union {
> > > +		struct {
> > > +			uint64_t packet_ok:1;
> > > +			/** The packet is valid after passing all HW checks.
> */
> >
> > The doxygen syntax is missing < but it will be fine when moved before.
> >
> Sure.
> 
> > > +			uint64_t l2_ok:1;
> > > +			/**< L2 layer is valid after passing all HW checks. */
> > > +			uint64_t l3_ok:1;
> > > +			/**< L3 layer is valid after passing all HW checks. */
> > > +			uint64_t l4_ok:1;
> > > +			/**< L4 layer is valid after passing all HW checks. */
> > > +			uint64_t l2_crc_ok:1;
> > > +			/**< L2 layer crc is valid. */
> >
> > s/crc/CRC/
> >
> O.K.
> 
> > > +			uint64_t ipv4_csum_ok:1;
> > > +			/**< IPv4 layer checksum is valid. */
> > > +			uint64_t l4_csum_ok:1;
> > > +			/**< L4 layer checksum is valid. */
> > > +			uint64_t l3_len_ok:1;
> > > +			/**< The l3 len is smaller than the frame len. */
> >
> > s/len/length/g
> >
> O.K.
> 
> > > +			uint64_t reserved:56;
> > > +		};
> > > +		uint64_t  value;
> >
> > double space
> >
> Sure.
> 
> > > +	};
> > > +};
> > > +
> > > +#ifndef __cplusplus
> > > +static const struct rte_flow_item_integrity
> > > +rte_flow_item_integrity_mask = {
> > > +	.level = 0,
> > > +	.value = 0,
> > > +};
> > > +#endif
> >
> > I'm pretty sure it breaks with some C compilers.
> > Why not for C++?
> > I see we have it already in rte_flow.h so we can keep it, but that's
> > something to double check for a future fix.
> >
> Just like you said this is the practice used already,
> 
> >