Re: [dpdk-dev] [PATCH] ethdev: add packet integrity checks

[Ori Kam <orika@nvidia.com>]

Hi,
Small answer update  to make the example more clear.
 (adding the mask to the item, in previous mail I assumed it is clear that the mask is on only
for the selected bits, but since it may not be clear I'm adding the mask in use)


In any case since RC1 is around the corner, I'm going to send V2 with the testpmd
implementation, which I hope makes things clearer.

> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of Ori Kam
> 
> Hi Andrew,
> 
> PSB,
> 
> Best,
> Ori
> > -----Original Message-----
> > From: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> >
> > On 4/8/21 2:39 PM, Ori Kam wrote:
> > > Hi Andrew,
> > >
> > > Thanks for your comments.
> > >
> > > PSB,
> > >
> > > Best,
> > > Ori
> > >
> > >> -----Original Message-----
> > >> From: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> > >> Sent: Thursday, April 8, 2021 11:05 AM
> > >> Subject: Re: [PATCH] ethdev: add packet integrity checks
> > >>
> > >> On 4/5/21 9:04 PM, Ori Kam wrote:
> > >>> 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
> > >>> (match all in low priority) that will direct the miss packet
> > >>> to the miss path.
> > >>>
> > >>> Since currenlty rte_flow works in positive way the assumtion is
> > >>> that the postive 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):
> > >>> 1. API breakage.
> > >>
> > >> First of all I disagree that "API breakage" is put as a top
> > >> priority. Design is a top priority, since it is a long term.
> > >> aPI breakage is just a short term inconvenient. Of course,
> > >> others may disagree, but that's my point of view.
> > >>
> > > I agree with you, and like I said the order of the list is not
> > > according to priorities.
> > > I truly believe that what I'm suggesting is the best design.
> > >
> > >
> > >>> 2. Simplicity.
> > >>> 3. Performance.
> > >>> 4. HW capabilities.
> > >>> 5. rte_flow limitation.
> > >>> 6. Flexability.
> > >>>
> > >>> 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.
> > >>
> > >> 3. Natively supports various tunnels without any extra
> > >>    changes in a shared item for all layers.
> > >>
> > > Also in the current suggested approach, we have the level member,
> > > So tunnels are supported by default. If someone wants to check also tunnel
> > > he just need to add this item again with the right level. (just like with other
> > > items)
> >
> > Thanks, missed it. Is it OK to have just one item with
> > level 1 or 2?
> >
> Yes, of course, if the application just wants to check the sanity of the inner
> packet he can
> just use one integrity item with level of 2.
> 
> 
> > What happens if two items with level 0 and level 1 are
> > specified, but the packet has no encapsulation?
> >
> Level zero is the default one (the default just like in RSS case is
> PMD dependent but in any case  from my knowledge layer 0 if there is no
> tunnel
> will point to the header) and level 1 is the outer most so in this case both of
> them
> are pointing to the same checks.
> But if for example we use level = 2 then the checks for level 2 should fail.
> Since the packet doesn't hold such info, just like if you check state of l4 and
> there is
> no l4 it should fails.
> 
> 
> > >>>
> > >>> 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.
> > >>
> > >> Could you expand it? Shouldn't HW offloaded flows with good
> > >> checksums go into dedicated queues where as bad packets go
> > >> via default path (i.e. no extra rules)?
> > >>
> > > I'm not sure what do you mean, in a lot of the cases
> > > Application will use that to detect valid packets and then
> > > forward only valid packets down the flow. (check valid jump
> > > --> on next group decap ....)
> > > In other cases the app may choose to drop the bad packets or count
> > > and then drop, maybe sample them to check this is not part of an attack.
> > >
> > > This is what is great about this feature we just give the app
> > > the ability to offload the sanity checks and be that enables it
> > > to offload the traffic itself
> >
> > Please, when you say "increase number of flows... in 5 flows"
> > just try to express in flow rules in both cases. Just for my
> > understanding. Since you calculated flows you should have a
> > real example.
> >
> Sure,  you are right I should have a better example.
> Lets take the example that the application want all valid traffic to
> jump to group 2.
> The possibilities of valid traffic can be:
> Eth / ipv4.
> Eth / ipv6
> Eth / ipv4 / udp
> Eth/ ivp4 / tcp
> Eth / ipv6 / udp
> Eth / ipv6 / tcp
> 
> So if we use the existing items we will get the following 6 flows:
> Flow create 0 ingress pattern eth / ipv4  valid = 1 / end action jump group 2
> Flow create 0 ingress pattern eth / ipv6  valid = 1 / end action jump group 2
> Flow create 0 ingress pattern eth / ipv4  valid = 1 / udp valid = 1/ end action
> jump group 2
> Flow create 0 ingress pattern eth / ipv4  valid = 1 / tcp valid = 1/ end action
> jump group 2
> Flow create 0 ingress pattern eth / ipv6  valid = 1 / udp valid = 1/ end action
> jump group 2
> Flow create 0 ingress pattern eth / ipv6  valid = 1 / udp valid = 1/ end action
> jump group 2
> 
> While if we use the new item approach:
> Flow create 0 ingress pattern integrity_check packet_ok =1 / end action jump
> group 2
Add the missing mask

 Flow create 0 ingress pattern integrity_check spec( packet_ok = 1) mask = (packet_ok = 1)  / end action jump
 group 2
> 
> 
> If we take the case that we just want valid l4 packets then the flows with
> existing items will be:
> Flow create 0 ingress pattern eth / ipv4  valid = 1 / udp valid = 1/ end action
> jump group 2
> Flow create 0 ingress pattern eth / ipv4  valid = 1 / tcp valid = 1/ end action
> jump group 2
> Flow create 0 ingress pattern eth / ipv6  valid = 1 / udp valid = 1/ end action
> jump group 2
> Flow create 0 ingress pattern eth / ipv6  valid = 1 / udp valid = 1/ end action
> jump group 2
> 
> While with the new item:
> Flow create 0 ingress pattern integrity_check l4_ok =1 / end action jump group
> 2
> 
Add the missing mask to the new item:
Flow create 0 ingress pattern integrity_check  spec = (l2_ok =1  | l3_ok = 1 | l4_ok = 1) mask = (l2_ok =1  | l3_ok = 1 | l4_ok = 1)  / end action jump group

> Is this clearer?
> 
> 
> > >>>
> > >>> 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.
> > >>
> > >> It depends on how bad (or good0 packets are handled.
> > >>
> > > Not sure what do you mean,
> >
> > Again, I hope we understand each other when we talk in terms
> > of real example and flow rules.
> >
> Please see answer above.
> I hope it will make things clearer.
> 
> > >>> 3. Simplicity application can just look at one place to see all possible
> > >>>    checks.
> > >>
> > >> It is a drawback from my point of view, since IPv4 checksum
> > >> check is out of IPv4 match item. I.e. analyzing IPv4 you should
> > >> take a look at 2 different flow items.
> > >>
> > > Are you talking from application view point, PMD  or HW?
> > > From application yes it is true he needs to add one more item
> > > to the list, (depending on his flows, since he can have just
> > > one flow that checks all packet like I said and move the good
> > > ones to a different group and in that group he will match the
> > > ipv4 item.
> > > For example:
> > > ... pattern integrity = valid action jump group 3
> > > Group 3 pattern .... ipv4 ... actions .....
> > > Group 3 pattern ....ipv6 .... actions ...
> > >
> > > In any case at worse case it is just adding one more item
> > > to the flow.
> > >
> > > From PMD/HW extra items doesn't mean extra action in HW
> > > they can be combined, just like they would have it the
> > > condition was in the item itself.
> > >
> > >>> 4. Allow future support for more tests.
> > >>
> > >> It is the same for both solution since per-item solution
> > >> can keep reserved bits which may be used in the future.
> > >>
> > > Yes I agree,
> > >
> > >>>
> > >>> Cons:
> > >>> 1. New item, that holds number of fields from different items.
> > >>
> > >> 2. Not that nice for tunnels.
> > >
> > > Please look at above (not direct ) response since we have the level member
> > > tunnels are handled very nicely.
> > >
> > >>
> > >>>
> > >>> 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 flor layer 2 have passed.
> > >>> 3. l3_ok - all check flor layer 2 have passed. If packet doens't have
> > >>>    l3 layer this check shoudl fail.
> > >>> 4. l4_ok - all check flor layer 2 have passed. If packet doesn't
> > >>>    have l4 layer this check should fail.
> > >>> 5. l2_crc_ok - the layer 2 crc is O.K. it is possible that the crc will
> > >>>    be O.K. but the l3_ok will be 0. it is not possible that l2_crc_ok will
> > >>>    be 0 and the l3_ok will be 0.
> > >>> 6. ipv4_csum_ok - IPv4 checksum is O.K.
> > >>> 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
> > >>>    packet 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@nvidia.com>
> > >>> ---
> > >>>  doc/guides/prog_guide/rte_flow.rst | 19 ++++++++++++++++
> > >>>  lib/librte_ethdev/rte_flow.h       | 46
> > >> ++++++++++++++++++++++++++++++++++++++
> > >>>  2 files changed, 65 insertions(+)
> > >>>
> > >>> diff --git a/doc/guides/prog_guide/rte_flow.rst
> > >> b/doc/guides/prog_guide/rte_flow.rst
> > >>> index aec2ba1..58b116e 100644
> > >>> --- a/doc/guides/prog_guide/rte_flow.rst
> > >>> +++ b/doc/guides/prog_guide/rte_flow.rst
> > >>> @@ -1398,6 +1398,25 @@ 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.
> > >>> +
> > >>> +- ``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.
> > >>> +  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 3 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 packet len.
> > >>> +
> > >>>  Actions
> > >>>  ~~~~~~~
> > >>>
> > >>> diff --git a/lib/librte_ethdev/rte_flow.h b/lib/librte_ethdev/rte_flow.h
> > >>> index 6cc5713..f6888a1 100644
> > >>> --- a/lib/librte_ethdev/rte_flow.h
> > >>> +++ b/lib/librte_ethdev/rte_flow.h
> > >>> @@ -551,6 +551,15 @@ enum rte_flow_item_type {
> > >>>  	 * See struct rte_flow_item_geneve_opt
> > >>>  	 */
> > >>>  	RTE_FLOW_ITEM_TYPE_GENEVE_OPT,
> > >>> +
> > >>> +	/**
> > >>> +	 * [META]
> > >>> +	 *
> > >>> +	 * Matches on packet integrity.
> > >>> +	 *
> > >>> +	 * See struct rte_flow_item_packet_integrity_checks.
> > >>> +	 */
> > >>> +	RTE_FLOW_ITEM_TYPE_PACKET_INTEGRITY_CHECKS,
> > >>>  };
> > >>>
> > >>>  /**
> > >>> @@ -1685,6 +1694,43 @@ struct rte_flow_item_geneve_opt {
> > >>>  };
> > >>>  #endif
> > >>>
> > >>> +struct rte_flow_item_packet_integrity_checks {
> > >>> +	uint32_t level;
> > >>> +	/**< Packet encapsulation level the item should apply to.
> > >>> +	 * @see rte_flow_action_rss
> > >>> +	 */
> > >>> +RTE_STD_C11
> > >>> +	union {
> > >>> +		struct {
> > >>> +			uint64_t packet_ok:1;
> > >>> +			/** The packet is valid after passing all HW checks. */
> > >>> +			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 checksum is valid. */
> > >>> +			uint64_t ipv4_csum_ok:1;
> > >>> +			/**< L3 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 packet len. */
> > >>> +			uint64_t reserved:56;
> > >>> +		};
> > >>> +		uint64_t  value;
> > >>> +	};
> > >>> +};
> > >>> +
> > >>> +#ifndef __cplusplus
> > >>> +static const struct rte_flow_item_sanity_checks
> > >>> +	rte_flow_item_sanity_checks_mask = {
> > >>> +		.value = 0,
> > >>> +};
> > >>> +#endif
> > >>> +
> > >>>  /**
> > >>>   * Matching pattern item definition.
> > >>>   *
> > >>>
> > >