Hi Akhil,
Please see inline.
Thanks,
Anoob
On 08-10-2018 15:19, Akhil Goyal wrote:
External Email
Hi Anoob,
@@ -494,6 +553,23 @@ IPsec related configuration parameters are
defined in ``rte_security_ipsec_xform
/**< Tunnel parameters, NULL for transport mode */
};
+PDCP related configuration parameters are defined in
``rte_security_pdcp_xform``
+
+.. code-block:: c
+
+ struct rte_security_pdcp_xform {
+ int8_t bearer; /**< PDCP bearer ID */
+ enum rte_security_pdcp_domain domain;
+ /** < PDCP mode of operation: Control or data */
+ enum rte_security_pdcp_direction pkt_dir;
+ /**< PDCP Frame Direction 0:UL 1:DL */
+ enum rte_security_pdcp_sn_size sn_size;
+ /**< Sequence number size, 5/7/12/15 */
+ int8_t hfn_ovd; /**< Overwrite HFN per operation */
+ uint32_t hfn; /**< Hyper Frame Number */
+ uint32_t hfn_threshold; /**< HFN Threashold for key
renegotiation */
+ };
+
[Anoob] PDCP packet ordering should be both a capability and a
setting.
HFN will be incremented overtime and starts at 0. So why is it part of
the xform?
The Security accelerators may assume packet in order. Latest PDCP TS
suggest to do de-Ciphering before re-Ordering the Rx PDCP PDUs. In this
situation, the accelerator may use wrong HFN value. The PDCP
application
can provide the appropriate HFN value along with PDU to the security
accelerator.
So what is the expectation with regards to ordering? Would PDCP know
the order or is it unaware of the order?
If implementation of this Spec knows the order of packets(which is
implied by the "In order delivery and Duplicate detection
Sequence Numbering" statement in the PDCP flow diagram), then there
should be no need to override the
HFN. If the implementation does not know the order of packets, then
the flow diagram should be corrected.
Also, is implementation expected to support ordered delivery and
duplicate detection. Perhaps it should be
a capability or 2.
This patchset is basically talking about full protocol offload with look
aside accelerators.
And when we are talking about full protocol offload, all protocol
related stuff like ordering, headers etc.
needs to be handled by the HW/driver.
So the expectation is driver/HW should be able to perform in order
delivery and detect duplicates.
How will errors in these situations be reported to the application - if
packets are not in order or if a duplicate is detected - how should
driver report it?
Is the driver/HW expected to correct the order OR is the behaviour
limited to detection of out-of-order? In order to correct the order, the
driver/HW will need to accumulate packets. Is that really the
expectation of this specification
If somebody have support for PDCP in the hardware, we can add
capabilities as per the specific requirements.
In v2/v3 I have removed the hfn_override. Will add it later when it will
be supported.
Thanks,
Akhil
