Re: [dpdk-dev] [EXT] [PATCH 1/2] ipsec: add transmit segmentation offload support

[Akhil Goyal <gakhil@marvell.com>]

> Subject: [EXT] [PATCH 1/2] ipsec: add transmit segmentation offload support
> 
Title should be ipsec: support TSO

> Add support for transmit segmentation offload to inline crypto processing
> mode. This offload is not supported by other offload modes, as at a
> minimum it requires inline crypto for IPsec to be supported on the
> network interface.
> 
> Signed-off-by: Declan Doherty <declan.doherty@intel.com>
> Signed-off-by: Radu Nicolau <radu.nicolau@intel.com>
> Signed-off-by: Abhijit Sinha <abhijit.sinha@intel.com>
> Signed-off-by: Daniel Martin Buckley <daniel.m.buckley@intel.com>
> Acked-by: Fan Zhang <roy.fan.zhang@intel.com>
> ---
>  doc/guides/prog_guide/ipsec_lib.rst    |   2 +
>  doc/guides/rel_notes/release_21_11.rst |   1 +
>  lib/ipsec/esp_outb.c                   | 131 +++++++++++++++++++------
>  3 files changed, 106 insertions(+), 28 deletions(-)
> 
> diff --git a/doc/guides/prog_guide/ipsec_lib.rst
> b/doc/guides/prog_guide/ipsec_lib.rst
> index 1bafdc608c..2a262f8c51 100644
> --- a/doc/guides/prog_guide/ipsec_lib.rst
> +++ b/doc/guides/prog_guide/ipsec_lib.rst
> @@ -315,6 +315,8 @@ Supported features
> 
>  *  NAT-T / UDP encapsulated ESP.
> 
> +*  TSO support (only for inline crypto mode)
> +
The word support can be dropped here as it is a list of supported features.

>  *  algorithms: 3DES-CBC, AES-CBC, AES-CTR, AES-GCM, AES_CCM,
> CHACHA20_POLY1305,
>     AES_GMAC, HMAC-SHA1, NULL.
> 
> diff --git a/doc/guides/rel_notes/release_21_11.rst
> b/doc/guides/rel_notes/release_21_11.rst
> index f6d2bc6f48..955b0bd68f 100644
> --- a/doc/guides/rel_notes/release_21_11.rst
> +++ b/doc/guides/rel_notes/release_21_11.rst
> @@ -201,6 +201,7 @@ New Features
>    * Added support for NAT-T / UDP encapsulated ESP
>    * Added support for SA telemetry.
>    * Added support for setting a non default starting ESN value.
> +  * Added support TSO offload support; only supported for inline crypto
> mode.

The word support is added three times in a single sentence.
It can be rephrased as
* Added support for TSO in inline crypto mode.


> 
> 
>  Removed Items
> diff --git a/lib/ipsec/esp_outb.c b/lib/ipsec/esp_outb.c
> index b6c72f58a4..c9fba662f2 100644
> --- a/lib/ipsec/esp_outb.c
> +++ b/lib/ipsec/esp_outb.c
> @@ -18,7 +18,7 @@
> 
>  typedef int32_t (*esp_outb_prepare_t)(struct rte_ipsec_sa *sa, rte_be64_t
> sqc,
>  	const uint64_t ivp[IPSEC_MAX_IV_QWORD], struct rte_mbuf *mb,
> -	union sym_op_data *icv, uint8_t sqh_len);
> +	union sym_op_data *icv, uint8_t sqh_len, uint8_t tso);
> 
>  /*
>   * helper function to fill crypto_sym op for cipher+auth algorithms.
> @@ -139,7 +139,7 @@ outb_cop_prepare(struct rte_crypto_op *cop,
>  static inline int32_t
>  outb_tun_pkt_prepare(struct rte_ipsec_sa *sa, rte_be64_t sqc,
>  	const uint64_t ivp[IPSEC_MAX_IV_QWORD], struct rte_mbuf *mb,
> -	union sym_op_data *icv, uint8_t sqh_len)
> +	union sym_op_data *icv, uint8_t sqh_len, uint8_t tso)
>  {
>  	uint32_t clen, hlen, l2len, pdlen, pdofs, plen, tlen;
>  	struct rte_mbuf *ml;
> @@ -157,11 +157,20 @@ outb_tun_pkt_prepare(struct rte_ipsec_sa *sa,
> rte_be64_t sqc,
> 
>  	/* number of bytes to encrypt */
>  	clen = plen + sizeof(*espt);
> -	clen = RTE_ALIGN_CEIL(clen, sa->pad_align);
> +
> +	/* We don't need to pad/align packet when using TSO offload */
> +	if (!tso)
> +		clen = RTE_ALIGN_CEIL(clen, sa->pad_align);
> +
> 
>  	/* pad length + esp tail */
>  	pdlen = clen - plen;
> -	tlen = pdlen + sa->icv_len + sqh_len;
> +
> +	/* We don't append ICV length when using TSO offload */
> +	if (!tso)
> +		tlen = pdlen + sa->icv_len + sqh_len;
> +	else
> +		tlen = pdlen + sqh_len;
This is a data path function, 2 extra checks are added for tso in the same function
if (tso) {
	pdlen = clen - plen;
	tlen = pdlen + sqh_len;
} else {
	clen = RTE_ALIGN_CEIL(clen, sa->pad_align);
	pdlen = clen - plen;
	tlen = pdlen + sa->icv_len + sqh_len;
}


> 
>  	/* do append and prepend */
>  	ml = rte_pktmbuf_lastseg(mb);
> @@ -309,7 +318,7 @@ esp_outb_tun_prepare(const struct
> rte_ipsec_session *ss, struct rte_mbuf *mb[],
> 
>  		/* try to update the packet itself */
>  		rc = outb_tun_pkt_prepare(sa, sqc, iv, mb[i], &icv,
> -					  sa->sqh_len);
> +					  sa->sqh_len, 0);
>  		/* success, setup crypto op */
>  		if (rc >= 0) {
>  			outb_pkt_xprepare(sa, sqc, &icv);
> @@ -336,7 +345,7 @@ esp_outb_tun_prepare(const struct
> rte_ipsec_session *ss, struct rte_mbuf *mb[],
>  static inline int32_t
>  outb_trs_pkt_prepare(struct rte_ipsec_sa *sa, rte_be64_t sqc,
>  	const uint64_t ivp[IPSEC_MAX_IV_QWORD], struct rte_mbuf *mb,
> -	union sym_op_data *icv, uint8_t sqh_len)
> +	union sym_op_data *icv, uint8_t sqh_len, uint8_t tso)
>  {
>  	uint8_t np;
>  	uint32_t clen, hlen, pdlen, pdofs, plen, tlen, uhlen;
> @@ -358,11 +367,19 @@ outb_trs_pkt_prepare(struct rte_ipsec_sa *sa,
> rte_be64_t sqc,
> 
>  	/* number of bytes to encrypt */
>  	clen = plen + sizeof(*espt);
> -	clen = RTE_ALIGN_CEIL(clen, sa->pad_align);
> +
> +	/* We don't need to pad/align packet when using TSO offload */
> +	if (!tso)
> +		clen = RTE_ALIGN_CEIL(clen, sa->pad_align);
> 
>  	/* pad length + esp tail */
>  	pdlen = clen - plen;
> -	tlen = pdlen + sa->icv_len + sqh_len;
> +
> +	/* We don't append ICV length when using TSO offload */
> +	if (!tso)
> +		tlen = pdlen + sa->icv_len + sqh_len;
> +	else
> +		tlen = pdlen + sqh_len;

Same comment as above.

> 
>  	/* do append and insert */
>  	ml = rte_pktmbuf_lastseg(mb);
> @@ -452,7 +469,7 @@ esp_outb_trs_prepare(const struct rte_ipsec_session
> *ss, struct rte_mbuf *mb[],
> 
>  		/* try to update the packet itself */
>  		rc = outb_trs_pkt_prepare(sa, sqc, iv, mb[i], &icv,
> -				  sa->sqh_len);
> +				  sa->sqh_len, 0);
>  		/* success, setup crypto op */
>  		if (rc >= 0) {
>  			outb_pkt_xprepare(sa, sqc, &icv);
> @@ -549,7 +566,7 @@ cpu_outb_pkt_prepare(const struct
> rte_ipsec_session *ss,
>  		gen_iv(ivbuf[k], sqc);
> 
>  		/* try to update the packet itself */
> -		rc = prepare(sa, sqc, ivbuf[k], mb[i], &icv, sa->sqh_len);
> +		rc = prepare(sa, sqc, ivbuf[k], mb[i], &icv, sa->sqh_len, 0);
> 
>  		/* success, proceed with preparations */
>  		if (rc >= 0) {
> @@ -668,6 +685,20 @@ inline_outb_mbuf_prepare(const struct
> rte_ipsec_session *ss,
>  	ss->sa->statistics.bytes += bytes;
>  }
> 
> +
> +static inline int
> +esn_outb_nb_segments(struct rte_mbuf *m)
> +{
> +	if  (m->ol_flags & (PKT_TX_TCP_SEG | PKT_TX_UDP_SEG)) {
> +		uint16_t pkt_l3len = m->pkt_len - m->l2_len;
> +		uint16_t segments =
> +			(m->tso_segsz > 0 && pkt_l3len > m->tso_segsz) ?
> +			(pkt_l3len + m->tso_segsz - 1) / m->tso_segsz : 1;
> +		return segments;

Directly return, no need for defining segments.

> +	}
> +	return 1; /* no TSO */
> +}
> +
>  /*
>   * process group of ESP outbound tunnel packets destined for
>   * INLINE_CRYPTO type of device.
> @@ -677,29 +708,51 @@ inline_outb_tun_pkt_process(const struct
> rte_ipsec_session *ss,
>  	struct rte_mbuf *mb[], uint16_t num)
>  {
>  	int32_t rc;
> -	uint32_t i, k, n;
> +	uint32_t i, k, nb_segs_t, n_sqn;

_t is normally used for typedefs. Can we rename it?

>  	uint64_t sqn;
>  	rte_be64_t sqc;
>  	struct rte_ipsec_sa *sa;
>  	union sym_op_data icv;
>  	uint64_t iv[IPSEC_MAX_IV_QWORD];
>  	uint32_t dr[num];
> +	uint16_t nb_segs[num];
> 
>  	sa = ss->sa;
> +	nb_segs_t = 0;
> +	/* Calculate number of segments */
> +	for (i = 0; i != num; i++) {
> +		nb_segs[i] = esn_outb_nb_segments(mb[i]);
> +		nb_segs_t += nb_segs[i];
> +	}
> 
> -	n = num;
> -	sqn = esn_outb_update_sqn(sa, &n);
> -	if (n != num)
> +	n_sqn = nb_segs_t;
> +	sqn = esn_outb_update_sqn(sa, &n_sqn);
> +	if (n_sqn != nb_segs_t) {
>  		rte_errno = EOVERFLOW;

If it is an error condition, shouldn't we return.
Also, I do not see rte_errno being checked anywhere in the app/test or ipsec-secgw.

> +		/* if there are segmented packets find out how many can be
> +		 * sent until overflow occurs
> +		 */
> +		if (nb_segs_t > num) { /* there is at least 1 */
> +			uint32_t seg_cnt = 0;
> +			for (i = 0; i < num && seg_cnt < n_sqn; i++)
> +				seg_cnt += nb_segs[i];
> +			num = i - 1;
> +		} else {
> +			num = n_sqn; /* no segmented packets */
> +		}
> +	}
>