On Sat, Jul 10, 2021 at 12:57:19PM +0000, Ananyev, Konstantin wrote:
>
> > > > > > > > > > For Tx inline processing, when
> > > > > > > > > > RTE_SECURITY_TX_OLOAD_NEED_MDATA is
> > > > > > > > > > set, rte_security_set_pkt_metadata() needs to be called for
> > > > > > > > > > pkts
> > > > > > > > > > to associate a Security session with a mbuf before
> > > > > > > > > > submitting
> > > > > > > > > > to Ethdev Tx. This is apart from setting PKT_TX_SEC_OFFLOAD
> > > > > > > > > > in
> > > > > > > > > > mbuf.ol_flags. rte_security_set_pkt_metadata() is also used
> > > > > > > > > > to
> > > > > > > > > > set some opaque metadata in mbuf for PMD's use.
> > > > > > > > > > This patch updates documentation that
> > > > > > > > > > rte_security_set_pkt_metadata()
> > > > > > > > > > should be called only with mbuf containing Layer 3 and
> > > > > > > > > > above data.
> > > > > > > > > > This behaviour is consistent with existing PMD's such as
> > > > > > > > > > ixgbe.
> > > > > > > > > >
> > > > > > > > > > On Tx, not all net PMD's/HW can parse packet and identify
> > > > > > > > > > L2 header and L3 header locations on Tx. This is inline
> > > > > > > > > > with other
> > > > > > > > > > Tx offloads requirements such as L3 checksum, L4 checksum
> > > > > > > > > > offload,
> > > > > > > > > > etc, where mbuf.l2_len, mbuf.l3_len etc, needs to be set for
> > > > > > > > > > HW to be able to generate checksum. Since Inline IPSec is
> > > > > > > > > > also
> > > > > > > > > > such a Tx offload, some PMD's at least need mbuf.l2_len to
> > > > > > > > > > be
> > > > > > > > > > valid to find L3 header and perform Outbound IPSec
> > > > > > > > > > processing.
> > > > > > > > > > Hence, this patch updates documentation to enforce setting
> > > > > > > > > > mbuf.l2_len while setting PKT_TX_SEC_OFFLOAD in
> > > > > > > > > > mbuf.ol_flags
> > > > > > > > > > for Inline IPSec Crypto / Protocol offload processing to
> > > > > > > > > > work on Tx.
> > > > > > > > > >
> > > > > > > > > > Signed-off-by: Nithin Dabilpuram <ndabilpu...@marvell.com>
> > > > > > > > > > Reviewed-by: Akhil Goyal <gak...@marvell.com>
> > > > > > > > > > ---
> > > > > > > > > > doc/guides/nics/features.rst | 2 ++
> > > > > > > > > > doc/guides/prog_guide/rte_security.rst | 6 +++++-
> > > > > > > > > > lib/mbuf/rte_mbuf_core.h | 2 ++
> > > > > > > > > > 3 files changed, 9 insertions(+), 1 deletion(-)
> > > > > > > > > >
> > > > > > > > > > diff --git a/doc/guides/nics/features.rst
> > > > > > > > > > b/doc/guides/nics/features.rst
> > > > > > > > > > index 403c2b03a..414baf14f 100644
> > > > > > > > > > --- a/doc/guides/nics/features.rst
> > > > > > > > > > +++ b/doc/guides/nics/features.rst
> > > > > > > > > > @@ -430,6 +430,7 @@ of protocol operations. See Security
> > > > > > > > > > library and PMD documentation for more deta
> > > > > > > > > >
> > > > > > > > > > * **[uses] rte_eth_rxconf,rte_eth_rxmode**:
> > > > > > > > > > ``offloads:DEV_RX_OFFLOAD_SECURITY``,
> > > > > > > > > > * **[uses] rte_eth_txconf,rte_eth_txmode**:
> > > > > > > > > > ``offloads:DEV_TX_OFFLOAD_SECURITY``.
> > > > > > > > > > +* **[uses] mbuf**: ``mbuf.l2_len``.
> > > > > > > > > > * **[implements] rte_security_ops**: ``session_create``,
> > > > > > > > > > ``session_update``,
> > > > > > > > > > ``session_stats_get``, ``session_destroy``,
> > > > > > > > > > ``set_pkt_metadata``, ``capabilities_get``.
> > > > > > > > > > * **[provides] rte_eth_dev_info**:
> > > > > > > > > > ``rx_offload_capa,rx_queue_offload_capa:DEV_RX_OFFLOAD_SECURITY``,
> > > > > > > > > > @@ -451,6 +452,7 @@ protocol operations. See security
> > > > > > > > > > library and PMD documentation for more details
> > > > > > > > > >
> > > > > > > > > > * **[uses] rte_eth_rxconf,rte_eth_rxmode**:
> > > > > > > > > > ``offloads:DEV_RX_OFFLOAD_SECURITY``,
> > > > > > > > > > * **[uses] rte_eth_txconf,rte_eth_txmode**:
> > > > > > > > > > ``offloads:DEV_TX_OFFLOAD_SECURITY``.
> > > > > > > > > > +* **[uses] mbuf**: ``mbuf.l2_len``.
> > > > > > > > > > * **[implements] rte_security_ops**: ``session_create``,
> > > > > > > > > > ``session_update``,
> > > > > > > > > > ``session_stats_get``, ``session_destroy``,
> > > > > > > > > > ``set_pkt_metadata``, ``get_userdata``,
> > > > > > > > > > ``capabilities_get``.
> > > > > > > > > > diff --git a/doc/guides/prog_guide/rte_security.rst
> > > > > > > > > > b/doc/guides/prog_guide/rte_security.rst
> > > > > > > > > > index f72bc8a78..7b68c698d 100644
> > > > > > > > > > --- a/doc/guides/prog_guide/rte_security.rst
> > > > > > > > > > +++ b/doc/guides/prog_guide/rte_security.rst
> > > > > > > > > > @@ -560,7 +560,11 @@ created by the application is attached
> > > > > > > > > > to the security session by the API
> > > > > > > > > >
> > > > > > > > > > For Inline Crypto and Inline protocol offload, device
> > > > > > > > > > specific defined metadata is
> > > > > > > > > > updated in the mbuf using
> > > > > > > > > > ``rte_security_set_pkt_metadata()`` if
> > > > > > > > > > -``DEV_TX_OFFLOAD_SEC_NEED_MDATA`` is set.
> > > > > > > > > > +``RTE_SECURITY_TX_OLOAD_NEED_MDATA`` is set.
> > > > > > > > > > ``rte_security_set_pkt_metadata()``
> > > > > > > > > > +should be called on mbuf only with Layer 3 and above data
> > > > > > > > > > present and
> > > > > > > > > > +``mbuf.data_off`` should be pointing to Layer 3 Header.
> > > > > > > > >
> > > > > > > > > Hmm... not sure why mbuf.data_off should point to L3 hdr.
> > > > > > > > > Who will add L2 hdr to the packet in that case?
> > > > > > > > > Or did you mean ``mbuf.data_off + mbuf.l2_len`` here?
> > > > > > > >
> > > > > > > > That is the semantics I was trying to define. I think below are
> > > > > > > > the sequence of
> > > > > > > > operations to be done for ipsec processing,
> > > > > > > >
> > > > > > > > 1. receive_pkt()
> > > > > > > > 2. strip_l2_hdr()
> > > > > > > > 3. Do policy lookup ()
> > > > > > > > 4. Call rte_security_set_pkt_metadata() if pkt needs to be
> > > > > > > > encrypted with a
> > > > > > > > particular SA. Now pkt only has L3 and above data.
> > > > > > > > 5. Do route_lookup()
> > > > > > > > 6. add_l2hdr() which might be different from stripped l2hdr.
> > > > > > > > 7. Send packet out.
> > > > > > > >
> > > > > > > > The above sequence is what I believe the current poll mode
> > > > > > > > worker thread in
> > > > > > > > ipsec-secgw is following.
> > > > > > >
> > > > > > > That's just a sample app, it doesn't mean it has to be the only
> > > > > > > possible way.
> > > > > > >
> > > > > > > > While in event mode, step 2 and step 6 are missing.
> > > > > > >
> > > > > > > I think this L2 hdr manipulation is totally optional.
> > > > > > > If your rte_security_set_pkt_metadata() implementation really
> > > > > > > needs to know L3 hdr offset (not sure why?),
> > > > > > Since rte_security_set_pkt_metadata() is PMD specific function ptr
> > > > > > call, we are currently doing some pre-processing
> > > > > > here before submitting packet to inline IPSec via
> > > > > > rte_eth_tx_burst(). This saves us cycles later in
> > > > > > rte_eth_tx_burst().
> > > > > > If we cannot know for sure, the pkt content at the time of
> > > > > > rte_security_set_pkt_metadata() call, then I think
> > > > > > having a PMD specific callback is not much of use except for saving
> > > > > > SA priv data to rte_mbuf.
> > > > > >
> > > > > > > then I suppose we can add a requirement that l2_len has to be set
> > > > > > > properly before calling rte_security_set_pkt_metadata().
> > > > > >
> > > > > > This is also fine with us.
> > > > >
> > > > > Ok, so to make sure we are on the same page, you propose:
> > > > > 1. before calling rte_security_set_pkt_metadata() mbuf.l2_len should
> > > > > be properly set.
> > > > > 2. after rte_security_set_pkt_metadata() and before
> > > > > rte_eth_tx_burst() packet contents
> > > > > at [mbuf.l2_len, mbuf.pkt_len) can't be modified?
> > > > Yes.
> > > >
> > > > >
> > > > > Is that correct understanding?
> > > > > If yes, I wonder how 2) will correlate with rte_eth_tx_prepare()
> > > > > concept?
> > > >
> > > > Since our PMD doesn't have a prepare function, I missed that but, since
> > > > rte_security_set_pkt_metadata() is only used for Inline Crypto/Protocol
> > > > via
> > > > a rte_eth_dev, and both rte_security_set_pkt_metadata() and
> > > > rte_eth_tx_prepare()
> > > > are callbacks from same PMD, do you see any issue ?
> > > >
> > > > The restriction is from user side, data is not supposed to be modified
> > > > unless
> > > > rte_security_set_pkt_metadata() is called again.
> > >
> > > Yep, I do have a concern here.
> > > Right now it is perfectly valid to do something like that:
> > > rte_security_set_pkt_metadata(..., mb, ...);
> > > /* can modify contents of the packet */
> > > rte_eth_tx_prepare(..., &mb, 1);
> > > rte_eth_tx_burst(..., &mb, 1);
> > >
> > > With the new restrictions you are proposing it wouldn't be allowed any
> > > more.
> > You can still modify L2 header and IPSEC is only concerned about L3 and
> > above.
> >
> > I think insisting that rte_security_set_pkt_metadata() be called after all
> > L3
> > and above header modifications is no a problem. I guess existing ixgbe/txgbe
> > PMD which are the ones only implementing the call back are already
> > expecting the
> > same ?
>
> AFAIK, no there are no such requirements for ixgbe or txgbe.
> All that ixgbe callback does - store session related data inside mbuf.
> It's only expectation to have ESP trailer at the proper place (after ICV):
This implies rte_security_set_pkt_metadata() cannot be called when mbuf does't
have ESP trailer updated or when mbuf->pkt_len = 0
>
> union ixgbe_crypto_tx_desc_md *mdata = (union ixgbe_crypto_tx_desc_md *)
> rte_security_dynfield(m);
> mdata->enc = 1;
> mdata->sa_idx = ic_session->sa_index;
> mdata->pad_len = ixgbe_crypto_compute_pad_len(m);
>
> Then this data will be used by tx_burst() function.
So it implies that after above rte_security_set_pkt_metadata() call, and before
tx_burst(),
mbuf data / packet len cannot be modified right as if modified, then tx_burst()
will be using incorrect pad len ?
This patch is also trying to add similar restriction on when
rte_security_set_pkt_metadata() should be called and what cannot be done after
calling rte_security_set_pkt_metadata().
>
> >
> > >
> > > >
> > > > If your question is can't we do the preprocessing in
> > > > rte_eth_tx_prepare() for
> > > > security,
> > >
> > > Yes, that was my thought.
> > >
> > > > my only argument was that since there is already a hit in
> > > > rte_security_set_pkt_metadata() to PMD specific callback and
> > > > struct rte_security_session is passed as an argument to it, it is more
> > > > benefitial to
> > > > do security related pre-processing there.
> > >
> > > Yes, it would be extra callback call that way.
> > > Though tx_prepare() accepts burst of packets, so the overhead
> > > of function call will be spread around the whole burst, and I presume
> > > shouldn't be too high.
> > >
> > > > Also rte_eth_tx_prepare() if implemented will be called for both
> > > > security and
> > > > non-security pkts.
> > >
> > > Yes, but tx_prepare() can distinguish (by ol_flags and/or other field
> > > contents) which
> > > modifications are required for the packet.
> >
> > But the major issues I see are
> >
> > 1. tx_prepare() doesn't take rte_security_session as argument though
> > ol_flags has security flag.
> > In our case, we need to know the security session details to do things.
>
> I suppose you can store pointer to session (or so) inside mbuf in
> rte_security_dynfield, no?
We can do. But having to call PMD specific function call via
rte_security_set_pkt_metadata()
just for storing session pointer in rte_security_dynfield consumes unnecessary
cycles per pkt.
>
> > 2. AFAIU tx_prepare() is not mandatory as per spec and even by default
> > disabled under compile time
> > macro RTE_ETHDEV_TX_PREPARE_NOOP.
> > 3. Even if we do tx_prepare(), rte_security_set_pkt_mdata() is mandatory to
> > associate
> > struct rte_security_session to a pkt as unlike ol_flags, there is no
> > direct space to do the same.
>
> Didn't get you here, obviously we do have rte_security_dynfield inside mbuf,
> specially for that - to store secuiryt related data inside the mbuf.
> Yes your PMD has to request it at initialization time, but I suppose it is
> not a big deal.
>
> > So I think instead of enforcing yet another callback tx_prepare() for
> > inline security
> > processing, it can be done via security specific set_pkt_metadata().
>
> But what you proposing introduces new limitations and might existing
> functionality.
> BTW, if you don't like to use tx_prepare() - why doing these calculations
> inside tx_burst()
> itself is not an option?
We can do things in tx_burst() but if we are doing it there, then we want to
avoid having callback for
rte_security_set_pkt_metadata().
Are you fine if we can update the spec that "When DEV_TX_OFFLOAD_SEC_NEED_MDATA
is not
set, then, user needs to update struct rte_security_session's sess_private_data
in a in
rte_security_dynfield like below ?
<snip>
static inline void
inline_outb_mbuf_prepare(const struct rte_ipsec_session *ss,
struct rte_mbuf *mb[], uint16_t num)
{
uint32_t i, ol_flags;
ol_flags = ss->security.ol_flags & RTE_SECURITY_TX_OLOAD_NEED_MDATA;
for (i = 0; i != num; i++) {
mb[i]->ol_flags |= PKT_TX_SEC_OFFLOAD;
if (ol_flags != 0)
rte_security_set_pkt_metadata(ss->security.ctx,
ss->security.ses, mb[i], NULL);
else
*rte_security_dynfield(mb[i]) =
(uint64_t)ss->security.ses->sess_private_data;
If the above can be done, then in our PMD, we will not have a callback for
set_pkt_metadata() and DEV_TX_OFFLOAD_SEC_NEED_MDATA will also be not set
in capabilities.
>
> > I'm fine to
> > introduce a burst call for the same(I was thinking to propose it in future)
> > to
> > compensate for the overhead.
> >
> > If rte_security_set_pkt_metadata() was not a PMD specific function ptr call
> > and
> > rte_mbuf had space for struct rte_security_session pointer,
>
> But it does, see above.
> In fact it even more flexible - because it is driver specific, you are not
> limited to one 64-bit field.
> If your PMD requires more data to be associated with mbuf
> - you can request it via mbuf_dynfield and store there whatever is needed.
>
> > then then I guess it would have been better to do the way you proposed.
> >
> > >
> > > >
> > > > >
> > > > > > >
> > > > > > > >
> > > > > > > > This patch is trying to enforce semantics as above so that
> > > > > > > > rte_security_set_pkt_metadata() can predict what comes in the
> > > > > > > > pkt when he is
> > > > > > > > called.
> > > > > > > >
> > > > > > > > I also think above sequence is what Linux kernel stack or other
> > > > > > > > stacks follow.
> > > > > > > > Does it makes sense ?
> > > > > > > >
> > > > > > > > >
> > > > > > > > > > Once called,
> > > > > > > > > > +Layer 3 and above data cannot be modified or moved around
> > > > > > > > > > unless
> > > > > > > > > > +``rte_security_set_pkt_metadata()`` is called again.
> > > > > > > > > >
> > > > > > > > > > For inline protocol offloaded ingress traffic, the
> > > > > > > > > > application can register a
> > > > > > > > > > pointer, ``userdata`` , in the security session. When the
> > > > > > > > > > packet is received,
> > > > > > > > > > diff --git a/lib/mbuf/rte_mbuf_core.h
> > > > > > > > > > b/lib/mbuf/rte_mbuf_core.h
> > > > > > > > > > index bb38d7f58..9d8e3ddc8 100644
> > > > > > > > > > --- a/lib/mbuf/rte_mbuf_core.h
> > > > > > > > > > +++ b/lib/mbuf/rte_mbuf_core.h
> > > > > > > > > > @@ -228,6 +228,8 @@ extern "C" {
> > > > > > > > > >
> > > > > > > > > > /**
> > > > > > > > > > * Request security offload processing on the TX packet.
> > > > > > > > > > + * To use Tx security offload, the user needs to fill
> > > > > > > > > > l2_len in mbuf
> > > > > > > > > > + * indicating L2 header size and where L3 header starts.
> > > > > > > > > > */
> > > > > > > > > > #define PKT_TX_SEC_OFFLOAD (1ULL << 43)
> > > > > > > > > >
> > > > > > > > > > --
> > > > > > > > > > 2.25.1
> > > > > > > > >
