RE: [PATCH v2 12/22] pdcp: add control PDU handling

[Anoob Joseph <anoobj@marvell.com>]

Hi Akhil,

Please see inline.

Thanks,
Anoob

> -----Original Message-----
> From: Akhil Goyal <gakhil@marvell.com>
> Sent: Thursday, May 18, 2023 2:45 PM
> To: Anoob Joseph <anoobj@marvell.com>; Thomas Monjalon
> <thomas@monjalon.net>; Jerin Jacob Kollanukkaran <jerinj@marvell.com>;
> Konstantin Ananyev <konstantin.v.ananyev@yandex.ru>; Bernard
> Iremonger <bernard.iremonger@intel.com>
> Cc: Hemant Agrawal <hemant.agrawal@nxp.com>; Mattias Rönnblom
> <mattias.ronnblom@ericsson.com>; Kiran Kumar Kokkilagadda
> <kirankumark@marvell.com>; Volodymyr Fialko <vfialko@marvell.com>;
> dev@dpdk.org; Olivier Matz <olivier.matz@6wind.com>
> Subject: RE: [PATCH v2 12/22] pdcp: add control PDU handling
> 
> > Subject: [PATCH v2 12/22] pdcp: add control PDU handling
> >
> > Add control PDU handling and implement status report generation.
> > Status report generation works only when RX_DELIV = RX_NEXT.
> >
> > Signed-off-by: Anoob Joseph <anoobj@marvell.com>
> > Signed-off-by: Volodymyr Fialko <vfialko@marvell.com>
> > ---
> >  app/test/test_pdcp.c               |  1 +
> 
> Separate out test app changes from library changes.

[Anoob] Agreed. Will make the change in next version.

> 
> >  doc/guides/prog_guide/pdcp_lib.rst | 10 +++++++
> >  lib/pdcp/meson.build               |  2 ++
> >  lib/pdcp/pdcp_cnt.c                | 29 ++++++++++++++++++
> >  lib/pdcp/pdcp_cnt.h                | 14 +++++++++
> >  lib/pdcp/pdcp_ctrl_pdu.c           | 46 +++++++++++++++++++++++++++++
> >  lib/pdcp/pdcp_ctrl_pdu.h           | 15 ++++++++++
> >  lib/pdcp/pdcp_entity.h             | 15 ++++++++--
> >  lib/pdcp/pdcp_process.c            | 13 +++++++++
> >  lib/pdcp/rte_pdcp.c                | 47 +++++++++++++++++++++++++++++-
> >  lib/pdcp/rte_pdcp.h                | 31 ++++++++++++++++++++
> >  lib/pdcp/version.map               |  2 ++
> >  12 files changed, 222 insertions(+), 3 deletions(-)  create mode
> > 100644 lib/pdcp/pdcp_cnt.c  create mode 100644 lib/pdcp/pdcp_cnt.h
> > create mode 100644 lib/pdcp/pdcp_ctrl_pdu.c  create mode 100644
> > lib/pdcp/pdcp_ctrl_pdu.h
> >
> > diff --git a/app/test/test_pdcp.c b/app/test/test_pdcp.c index
> > fc49947ba2..4ecb4d9572 100644
> > --- a/app/test/test_pdcp.c
> > +++ b/app/test/test_pdcp.c
> > @@ -415,6 +415,7 @@ create_test_conf_from_index(const int index,
> > struct pdcp_test_conf *conf)
> >
> >  	conf->entity.sess_mpool = ts_params->sess_pool;
> >  	conf->entity.cop_pool = ts_params->cop_pool;
> > +	conf->entity.ctr_pdu_pool = ts_params->mbuf_pool;
> >  	conf->entity.pdcp_xfrm.bearer = pdcp_test_bearer[index];
> >  	conf->entity.pdcp_xfrm.en_ordering = 0;
> >  	conf->entity.pdcp_xfrm.remove_duplicates = 0; diff --git
> > a/doc/guides/prog_guide/pdcp_lib.rst
> > b/doc/guides/prog_guide/pdcp_lib.rst
> > index abd874f2cc..f23360dfc3 100644
> > --- a/doc/guides/prog_guide/pdcp_lib.rst
> > +++ b/doc/guides/prog_guide/pdcp_lib.rst
> > @@ -67,6 +67,15 @@ Data PDUs are regular packets submitted by upper
> > layers for transmission to  other end. Such packets would need to be
> > ciphered and authenticated based on  the entity configuration.
> >
> > +PDCP packet processing API for control PDU
> > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > +
> > +Control PDUs are used in PDCP as a communication channel between
> > transmitting
> > +and receiving entities. When upper layer request for operations such
> > +re-establishment, receiving PDCP entity need to prepare a status
> > +report and send it to the other end. The API
> > +``pdcp_ctrl_pdu_status_gen`` allows application to request the same.
> 
> pdcp_ctrl_pdu_status_gen() - Is this a user visible API? I believe it is not
> exposed.
> How can application request that?

[Anoob] Quoted wrong API. It should be 'rte_pdcp_control_pdu_create()'. Will have this corrected in next version.

> 
> 
> > +
> >  PDCP packet processing API for data PDU
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >
> > @@ -228,6 +237,7 @@ Supported features
> >  - Uplink & downlink traffic
> >  - HFN increment
> >  - IV generation as required per algorithm
> > +- Control PDU generation
> >
> >  Supported ciphering algorithms
> >  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > diff --git a/lib/pdcp/meson.build b/lib/pdcp/meson.build index
> > 08679b743a..75d476bf6d 100644
> > --- a/lib/pdcp/meson.build
> > +++ b/lib/pdcp/meson.build
> > @@ -8,7 +8,9 @@ if is_windows
> >  endif
> >
> >  sources = files(
> > +        'pdcp_cnt.c',
> 
> pdcp_cnt seems to be something related to count.
> And it is not related to this patch probably.

[Anoob] 'pdcp_cnt' tracks the sequence number of the received packets etc. This info is required for generating status report which is one of the control PDUs supported. 

> 
> >          'pdcp_crypto.c',
> > +        'pdcp_ctrl_pdu.c',
> >          'pdcp_process.c',
> >          'rte_pdcp.c',
> >          )
> > diff --git a/lib/pdcp/pdcp_cnt.c b/lib/pdcp/pdcp_cnt.c new file mode
> > 100644 index 0000000000..c9b952184b
> > --- /dev/null
> > +++ b/lib/pdcp/pdcp_cnt.c
> > @@ -0,0 +1,29 @@
> > +/* SPDX-License-Identifier: BSD-3-Clause
> > + * Copyright(C) 2023 Marvell.
> > + */
> > +
> > +#include <rte_pdcp.h>
> > +
> > +#include "pdcp_cnt.h"
> > +#include "pdcp_entity.h"
> > +
> > +int
> > +pdcp_cnt_ring_create(struct rte_pdcp_entity *en, const struct
> > rte_pdcp_entity_conf *conf)
> > +{
> > +	struct entity_priv_dl_part *en_priv_dl;
> > +	uint32_t window_sz;
> > +
> > +	if (en == NULL || conf == NULL)
> > +		return -EINVAL;
> > +
> > +	if (conf->pdcp_xfrm.pkt_dir == RTE_SECURITY_PDCP_UPLINK)
> > +		return 0;
> > +
> > +	en_priv_dl = entity_dl_part_get(en);
> > +	window_sz = pdcp_window_size_get(conf->pdcp_xfrm.sn_size);
> > +
> > +	RTE_SET_USED(window_sz);
> > +	RTE_SET_USED(en_priv_dl);
> > +
> > +	return 0;
> > +}
> > diff --git a/lib/pdcp/pdcp_cnt.h b/lib/pdcp/pdcp_cnt.h new file mode
> > 100644 index 0000000000..bbda478b55
> > --- /dev/null
> > +++ b/lib/pdcp/pdcp_cnt.h
> > @@ -0,0 +1,14 @@
> > +/* SPDX-License-Identifier: BSD-3-Clause
> > + * Copyright(C) 2023 Marvell.
> > + */
> > +
> > +#ifndef PDCP_CNT_H
> > +#define PDCP_CNT_H
> > +
> > +#include <rte_common.h>
> > +
> > +#include "pdcp_entity.h"
> > +
> > +int pdcp_cnt_ring_create(struct rte_pdcp_entity *en, const struct
> > rte_pdcp_entity_conf *conf);
> > +
> > +#endif /* PDCP_CNT_H */
> > diff --git a/lib/pdcp/pdcp_ctrl_pdu.c b/lib/pdcp/pdcp_ctrl_pdu.c new
> > file mode 100644 index 0000000000..feb05fd863
> > --- /dev/null
> > +++ b/lib/pdcp/pdcp_ctrl_pdu.c
> > @@ -0,0 +1,46 @@
> > +/* SPDX-License-Identifier: BSD-3-Clause
> > + * Copyright(C) 2023 Marvell.
> > + */
> > +
> > +#include <rte_byteorder.h>
> > +#include <rte_mbuf.h>
> > +#include <rte_pdcp_hdr.h>
> > +
> > +#include "pdcp_ctrl_pdu.h"
> > +#include "pdcp_entity.h"
> > +
> > +static __rte_always_inline void
> > +pdcp_hdr_fill(struct rte_pdcp_up_ctrl_pdu_hdr *pdu_hdr, uint32_t
> > +rx_deliv) {
> > +	pdu_hdr->d_c = RTE_PDCP_PDU_TYPE_CTRL;
> > +	pdu_hdr->pdu_type =
> RTE_PDCP_CTRL_PDU_TYPE_STATUS_REPORT;
> > +	pdu_hdr->r = 0;
> > +	pdu_hdr->fmc = rte_cpu_to_be_32(rx_deliv); }
> > +
> > +int
> > +pdcp_ctrl_pdu_status_gen(struct entity_priv *en_priv, struct rte_mbuf
> > +*m) {
> > +	struct rte_pdcp_up_ctrl_pdu_hdr *pdu_hdr;
> > +	uint32_t rx_deliv;
> > +	int pdu_sz;
> > +
> > +	if (!en_priv->flags.is_status_report_required)
> > +		return -EINVAL;
> > +
> > +	pdu_sz = sizeof(struct rte_pdcp_up_ctrl_pdu_hdr);
> > +
> > +	rx_deliv = en_priv->state.rx_deliv;
> > +
> > +	/* Zero missing PDUs - status report contains only FMC */
> > +	if (rx_deliv >= en_priv->state.rx_next) {
> > +		pdu_hdr = (struct rte_pdcp_up_ctrl_pdu_hdr
> > *)rte_pktmbuf_append(m, pdu_sz);
> > +		if (pdu_hdr == NULL)
> > +			return -ENOMEM;
> > +		pdcp_hdr_fill(pdu_hdr, rx_deliv);
> > +
> > +		return 0;
> > +	}
> > +
> > +	return -ENOTSUP;
> > +}
> > diff --git a/lib/pdcp/pdcp_ctrl_pdu.h b/lib/pdcp/pdcp_ctrl_pdu.h new
> > file mode 100644 index 0000000000..a2424fbd10
> > --- /dev/null
> > +++ b/lib/pdcp/pdcp_ctrl_pdu.h
> > @@ -0,0 +1,15 @@
> > +/* SPDX-License-Identifier: BSD-3-Clause
> > + * Copyright(C) 2023 Marvell.
> > + */
> > +
> > +#ifndef PDCP_CTRL_PDU_H
> > +#define PDCP_CTRL_PDU_H
> > +
> > +#include <rte_mbuf.h>
> > +
> > +#include "pdcp_entity.h"
> > +
> > +int
> > +pdcp_ctrl_pdu_status_gen(struct entity_priv *en_priv, struct rte_mbuf
> > +*m);
> > +
> > +#endif /* PDCP_CTRL_PDU_H */
> > diff --git a/lib/pdcp/pdcp_entity.h b/lib/pdcp/pdcp_entity.h index
> > 3108795977..7b7e7f69dd 100644
> > --- a/lib/pdcp/pdcp_entity.h
> > +++ b/lib/pdcp/pdcp_entity.h
> > @@ -109,6 +109,13 @@ union cipher_iv_partial {
> >  	uint64_t u64[2];
> >  };
> >
> > +struct pdcp_cnt_bitmap {
> > +	/** Number of entries that can be stored. */
> > +	uint32_t size;
> > +	/** Bitmap of the count values already received.*/
> > +	struct rte_bitmap *bmp;
> > +};
> 
> This pdcp_cnt_bitmap is not related to control PDU. Right?
> I believe the patch split is not proper here.

[Anoob] Bitmap is required for generating status report. With this patch, we are adding support for control PDU handling and adding basic support for status report generation. 

> 
> > +
> >  /*
> >   * Layout of PDCP entity: [rte_pdcp_entity] [entity_priv] [entity_dl/ul]
> >   */
> > @@ -136,9 +143,13 @@ struct entity_priv {
> >  		uint64_t is_ul_entity : 1;
> >  		/** Is NULL auth. */
> >  		uint64_t is_null_auth : 1;
> > +		/** Is status report required.*/
> > +		uint64_t is_status_report_required : 1;
> >  	} flags;
> >  	/** Crypto op pool. */
> >  	struct rte_mempool *cop_pool;
> > +	/** Control PDU pool. */
> > +	struct rte_mempool *ctr_pdu_pool;
> >  	/** PDCP header size. */
> >  	uint8_t hdr_sz;
> >  	/** PDCP AAD size. For AES-CMAC, additional message is prepended
> for
> > the operation. */ @@ -148,8 +159,8 @@ struct entity_priv {  };
> >
> >  struct entity_priv_dl_part {
> > -	/* NOTE: when in-order-delivery is supported, post PDCP packets
> would
> > need to cached. */
> > -	uint8_t dummy;
> > +	/** PDCP would need to track the count values that are already
> > received.*/
> > +	struct pdcp_cnt_bitmap bitmap;
> >  };
> >
> >  struct entity_priv_ul_part {
> > diff --git a/lib/pdcp/pdcp_process.c b/lib/pdcp/pdcp_process.c index
> > 9c1a5e0669..267b3b7723 100644
> > --- a/lib/pdcp/pdcp_process.c
> > +++ b/lib/pdcp/pdcp_process.c
> > @@ -1157,6 +1157,19 @@ pdcp_entity_priv_populate(struct entity_priv
> > *en_priv, const struct rte_pdcp_ent
> >  	if (a_xfrm != NULL && a_xfrm->auth.algo ==
> > RTE_CRYPTO_AUTH_NULL)
> >  		en_priv->flags.is_null_auth = 1;
> >
> > +	/**
> > +	 * flags.is_status_report_required
> > +	 *
> > +	 * Indicate whether status report is required.
> > +	 */
> > +	if (conf->status_report_required) {
> > +		/** Status report is required only for DL entities. */
> > +		if (conf->pdcp_xfrm.pkt_dir !=
> > RTE_SECURITY_PDCP_DOWNLINK)
> > +			return -EINVAL;
> > +
> > +		en_priv->flags.is_status_report_required = 1;
> > +	}
> > +
> >  	/**
> >  	 * hdr_sz
> >  	 *
> > diff --git a/lib/pdcp/rte_pdcp.c b/lib/pdcp/rte_pdcp.c index
> > 8914548dbd..5cd3f5ca31 100644
> > --- a/lib/pdcp/rte_pdcp.c
> > +++ b/lib/pdcp/rte_pdcp.c
> > @@ -6,7 +6,9 @@
> >  #include <rte_pdcp.h>
> >  #include <rte_malloc.h>
> >
> > +#include "pdcp_cnt.h"
> >  #include "pdcp_crypto.h"
> > +#include "pdcp_ctrl_pdu.h"
> >  #include "pdcp_entity.h"
> >  #include "pdcp_process.h"
> >
> > @@ -34,7 +36,7 @@ rte_pdcp_entity_establish(const struct
> > rte_pdcp_entity_conf *conf)
> >  	struct entity_priv *en_priv;
> >  	int ret, entity_size;
> >
> > -	if (conf == NULL || conf->cop_pool == NULL) {
> > +	if (conf == NULL || conf->cop_pool == NULL || conf->ctr_pdu_pool
> ==
> > NULL) {
> >  		rte_errno = -EINVAL;
> >  		return NULL;
> >  	}
> > @@ -79,6 +81,7 @@ rte_pdcp_entity_establish(const struct
> > rte_pdcp_entity_conf *conf)
> >  	en_priv->state.rx_deliv = conf->count;
> >  	en_priv->state.tx_next = conf->count;
> >  	en_priv->cop_pool = conf->cop_pool;
> > +	en_priv->ctr_pdu_pool = conf->ctr_pdu_pool;
> >
> >  	/* Setup crypto session */
> >  	ret = pdcp_crypto_sess_create(entity, conf); @@ -89,6 +92,10 @@
> > rte_pdcp_entity_establish(const struct rte_pdcp_entity_conf *conf)
> >  	if (ret)
> >  		goto crypto_sess_destroy;
> >
> > +	ret = pdcp_cnt_ring_create(entity, conf);
> > +	if (ret)
> > +		goto crypto_sess_destroy;
> > +
> >  	return entity;
> >
> >  crypto_sess_destroy:
> > @@ -136,3 +143,41 @@ rte_pdcp_entity_suspend(struct rte_pdcp_entity
> > *pdcp_entity,
> >
> >  	return 0;
> >  }
> > +
> > +struct rte_mbuf *
> > +rte_pdcp_control_pdu_create(struct rte_pdcp_entity *pdcp_entity,
> > +			    enum rte_pdcp_ctrl_pdu_type type) {
> > +	struct entity_priv *en_priv;
> > +	struct rte_mbuf *m;
> > +	int ret;
> > +
> > +	if (pdcp_entity == NULL) {
> > +		rte_errno = -EINVAL;
> 
> rte_errno should be positive values.
> 
> > +		return NULL;
> > +	}
> > +
> > +	en_priv = entity_priv_get(pdcp_entity);
> > +
> > +	m = rte_pktmbuf_alloc(en_priv->ctr_pdu_pool);
> > +	if (m == NULL) {
> > +		rte_errno = -ENOMEM;
> > +		return NULL;
> > +	}
> > +
> > +	switch (type) {
> > +	case RTE_PDCP_CTRL_PDU_TYPE_STATUS_REPORT:
> > +		ret = pdcp_ctrl_pdu_status_gen(en_priv, m);
> > +		break;
> > +	default:
> > +		ret = -ENOTSUP;
> > +	}
> > +
> > +	if (ret) {
> > +		rte_pktmbuf_free(m);
> > +		rte_errno = ret;
> > +		return NULL;
> > +	}
> > +
> > +	return m;
> > +}
> > diff --git a/lib/pdcp/rte_pdcp.h b/lib/pdcp/rte_pdcp.h index
> > 54f88e3fd3..d2db25d7d9 100644
> > --- a/lib/pdcp/rte_pdcp.h
> > +++ b/lib/pdcp/rte_pdcp.h
> > @@ -16,6 +16,7 @@
> >  #include <rte_compat.h>
> >  #include <rte_common.h>
> >  #include <rte_mempool.h>
> > +#include <rte_pdcp_hdr.h>
> >  #include <rte_security.h>
> >
> >  #ifdef __cplusplus
> > @@ -78,6 +79,8 @@ struct rte_pdcp_entity_conf {
> >  	struct rte_mempool *sess_mpool;
> >  	/** Crypto op pool.*/
> >  	struct rte_mempool *cop_pool;
> > +	/** Mbuf pool to be used for allocating control PDUs.*/
> > +	struct rte_mempool *ctr_pdu_pool;
> 
> Please use same prefix for all control pdu stuff.
> I see cnt, ctr, ctrl, control is being used.
> I think "control" for top level API and "ctrl" for parameters should be fine.

[Anoob] Agreed. Will make this change in next version.

> 
> >  	/**
> >  	 * 32 bit count value (HFN + SN) to be used for the first packet.
> >  	 * pdcp_xfrm.hfn would be ignored as the HFN would be derived
> from
> > this value.
> > @@ -91,6 +94,15 @@ struct rte_pdcp_entity_conf {
> >  	uint8_t dev_id;
> >  	/** Reverse direction during IV generation. Can be used to simulate
> > UE crypto processing.*/
> >  	bool reverse_iv_direction;
> > +	/**
> > +	 * Status report required (specified in TS 38.331).
> > +	 *
> > +	 * If PDCP entity is configured to send a PDCP status report, the
> > +upper
> > layer application
> > +	 * may request a receiving PDCP entity to generate a PDCP status
> > +report
> > using
> > +	 * ``rte_pdcp_ctrl_pdu_create``. In addition, PDCP status reports
> > +may be
> > generated during
> > +	 * operations such as entity re-establishment.
> > +	 */
> > +	bool status_report_required;
> 
> rte_pdcp_ctrl_pdu_create -> rte_pdcp_control_pdu_create
> 
> Please specify that a PDU will be generated for status report.
> Otherwise, it seems some structure would be returned for status report But
> there is no mention of that. This will avoid confusion.

[Anoob] Agreed. Will update documentation of rte_pdcp_control_pdu_create() to denote that it is lib PDCP which would allocate the packet.

> 
> 
> >  };
> >  /* >8 End of structure rte_pdcp_entity_conf. */
> >
> > @@ -169,6 +181,25 @@ int
> >  rte_pdcp_entity_suspend(struct rte_pdcp_entity *pdcp_entity,
> >  			struct rte_mbuf *out_mb[]);
> >
> > +/**
> > + * @warning
> > + * @b EXPERIMENTAL: this API may change without prior notice
> > + *
> > + * Create control PDU packet of the `type` specified.
> > + *
> > + * @param pdcp_entity
> > + *   Pointer to the PDCP entity for which the control PDU need to be
> generated.
> > + * @param type
> > + *   Type of control PDU to be generated.
> > + * @return
> > + *   - Control PDU generated, in case of success.
> > + *   - NULL in case of failure. rte_errno will be set to error code.
> > + */
> > +__rte_experimental
> > +struct rte_mbuf *
> > +rte_pdcp_control_pdu_create(struct rte_pdcp_entity *pdcp_entity,
> > +			    enum rte_pdcp_ctrl_pdu_type type);
> > +
> >  /**
> >   * @warning
> >   * @b EXPERIMENTAL: this API may change without prior notice diff
> > --git a/lib/pdcp/version.map b/lib/pdcp/version.map index
> > f9ff30600a..d0cf338e1f 100644
> > --- a/lib/pdcp/version.map
> > +++ b/lib/pdcp/version.map
> > @@ -6,6 +6,8 @@ EXPERIMENTAL {
> >  	rte_pdcp_entity_release;
> >  	rte_pdcp_entity_suspend;
> >
> > +	rte_pdcp_control_pdu_create;
> > +
> >  	rte_pdcp_pkt_post_process;
> >  	rte_pdcp_pkt_pre_process;
> >
> > --
> > 2.25.1