Re: [dpdk-dev] [PATCH v6 06/10] ipsec: add transmit segmentation offload support

["Nicolau, Radu" <radu.nicolau@intel.com>]

On 9/23/2021 3:09 PM, Ananyev, Konstantin wrote:
>
>> 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>
>> ---
>>   lib/ipsec/esp_inb.c  |   4 +-
>>   lib/ipsec/esp_outb.c | 115 +++++++++++++++++++++++++++++++++++--------
>>   lib/ipsec/iph.h      |  10 +++-
>>   lib/ipsec/sa.c       |   6 +++
>>   lib/ipsec/sa.h       |   4 ++
>>   5 files changed, 114 insertions(+), 25 deletions(-)
>>
>> diff --git a/lib/ipsec/esp_inb.c b/lib/ipsec/esp_inb.c
>> index d66c88f05d..a6ab8fbdd5 100644
>> --- a/lib/ipsec/esp_inb.c
>> +++ b/lib/ipsec/esp_inb.c
>> @@ -668,8 +668,8 @@ trs_process(const struct rte_ipsec_sa *sa, struct rte_mbuf *mb[],
>>   			/* modify packet's layout */
>>   			np = trs_process_step2(mb[i], ml[i], hl[i], cofs,
>>   				to[i], tl, sqn + k);
>> -			update_trs_l3hdr(sa, np + l2, mb[i]->pkt_len,
>> -				l2, hl[i] - l2, espt[i].next_proto);
>> +			update_trs_l34hdrs(sa, np + l2, mb[i]->pkt_len,
>> +				l2, hl[i] - l2, espt[i].next_proto, 0);
>>
>>   			/* update mbuf's metadata */
>>   			trs_process_step3(mb[i]);
>> diff --git a/lib/ipsec/esp_outb.c b/lib/ipsec/esp_outb.c
>> index a3f77469c3..9fc7075796 100644
>> --- a/lib/ipsec/esp_outb.c
>> +++ b/lib/ipsec/esp_outb.c
>> @@ -2,6 +2,8 @@
>>    * Copyright(c) 2018-2020 Intel Corporation
>>    */
>>
>> +#include <math.h>
>> +
>>   #include <rte_ipsec.h>
>>   #include <rte_esp.h>
>>   #include <rte_ip.h>
>> @@ -156,11 +158,20 @@ 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/ailgn packet when using TSO offload */
>> +	if (likely(!(mb->ol_flags & (PKT_TX_TCP_SEG | PKT_TX_UDP_SEG))))
>> +		clen = RTE_ALIGN_CEIL(clen, sa->pad_align);
>> +
> Here and everywhere:
> It doesn't look nice that we have to pollute generic functions with
> checking TSO specific flags all over the place.
> Can we probably have a specific prepare/process function for inline+tso case?
> As we do have for cpu and inline cases right now.
> Or just update inline version?
I looked at doing this but unless I copy these 2 functions I can't move 
this out.
>
>>   	/* 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 (likely(!(mb->ol_flags & (PKT_TX_TCP_SEG | PKT_TX_UDP_SEG))))
>> +		tlen = pdlen + sa->icv_len + sqh_len;
>> +	else
>> +		tlen = pdlen + sqh_len;
>>
>>   	/* do append and prepend */
>>   	ml = rte_pktmbuf_lastseg(mb);
>> @@ -337,6 +348,7 @@ outb_trs_pkt_prepare(struct rte_ipsec_sa *sa, rte_be64_t sqc,
>>   	char *ph, *pt;
>>   	uint64_t *iv;
>>   	uint32_t l2len, l3len;
>> +	uint8_t tso = mb->ol_flags & (PKT_TX_TCP_SEG | PKT_TX_UDP_SEG) ? 1 : 0;
>>
>>   	l2len = mb->l2_len;
>>   	l3len = mb->l3_len;
>> @@ -349,11 +361,19 @@ 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/ailgn packet when using TSO offload */
>> +	if (likely(!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 (likely(!tso))
>> +		tlen = pdlen + sa->icv_len + sqh_len;
>> +	else
>> +		tlen = pdlen + sqh_len;
>>
>>   	/* do append and insert */
>>   	ml = rte_pktmbuf_lastseg(mb);
>> @@ -375,8 +395,8 @@ outb_trs_pkt_prepare(struct rte_ipsec_sa *sa, rte_be64_t sqc,
>>   	insert_esph(ph, ph + hlen, uhlen);
>>
>>   	/* update ip  header fields */
>> -	np = update_trs_l3hdr(sa, ph + l2len, mb->pkt_len - sqh_len, l2len,
>> -			l3len, IPPROTO_ESP);
>> +	np = update_trs_l34hdrs(sa, ph + l2len, mb->pkt_len - sqh_len, l2len,
>> +			l3len, IPPROTO_ESP, tso);
>>
>>   	/* update spi, seqn and iv */
>>   	esph = (struct rte_esp_hdr *)(ph + uhlen);
>> @@ -651,6 +671,33 @@ inline_outb_mbuf_prepare(const struct rte_ipsec_session *ss,
>>   	}
>>   }
>>
>> +/* check if packet will exceed MSS and segmentation is required */
>> +static inline int
>> +esn_outb_nb_segments(const struct rte_ipsec_sa *sa, struct rte_mbuf *m) {
>> +	uint16_t segments = 1;
>> +	uint16_t pkt_l3len = m->pkt_len - m->l2_len;
>> +
>> +	/* Only support segmentation for UDP/TCP flows */
>> +	if (!(m->packet_type & (RTE_PTYPE_L4_UDP | RTE_PTYPE_L4_TCP)))
>> +		return segments;
>> +
>> +	if (sa->tso.enabled && pkt_l3len > sa->tso.mss) {
>> +		segments = ceil((float)pkt_l3len / sa->tso.mss);
> Float calculations in the middle of data-path?
> Just to calculate roundup?
> Doesn't look good to me at all.
It doesn't look good to me either - I will rework it.
>
>> +
>> +		if  (m->packet_type & RTE_PTYPE_L4_TCP) {
>> +			m->ol_flags |= (PKT_TX_TCP_SEG | PKT_TX_TCP_CKSUM);
> That's really strange - why ipsec library will set PKT_TX_TCP_SEG unconditionally?
> That should be responsibility of the upper layer, I think.
> In the lib we should only check was tso requested for that packet or not.
> Same for UDP.
These are under an if(TSO) condition.
>
>> +			m->l4_len = sizeof(struct rte_tcp_hdr);
> Hmm, how do we know there are no TCP options present for that packet?
> Wouldn't it be better to expect user to provide proper l4_len for such packets?
You're right, I will update it.

>
>> +		} else {
>> +			m->ol_flags |= (PKT_TX_UDP_SEG | PKT_TX_UDP_CKSUM);
>> +			m->l4_len = sizeof(struct rte_udp_hdr);
>> +		}
>> +
>> +		m->tso_segsz = sa->tso.mss;
>> +	}
>> +
>> +	return segments;
>> +}
>> +
>>   /*
>>    * process group of ESP outbound tunnel packets destined for
>>    * INLINE_CRYPTO type of device.
>> @@ -660,24 +707,29 @@ 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_sqn = 0, nb_sqn_alloc;
>>   	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;
>>
>> -	n = num;
>> -	sqn = esn_outb_update_sqn(sa, &n);
>> -	if (n != num)
>> +	for (i = 0; i != num; i++) {
>> +		nb_segs[i] = esn_outb_nb_segments(sa, mb[i]);
>> +		nb_sqn += nb_segs[i];
>> +	}
>> +
>> +	nb_sqn_alloc = nb_sqn;
>> +	sqn = esn_outb_update_sqn(sa, &nb_sqn_alloc);
>> +	if (nb_sqn_alloc != nb_sqn)
>>   		rte_errno = EOVERFLOW;
>>
>>   	k = 0;
>> -	for (i = 0; i != n; i++) {
>> -
>> +	for (i = 0; i != num; i++) {
>>   		sqc = rte_cpu_to_be_64(sqn + i);
>>   		gen_iv(iv, sqc);
>>
>> @@ -691,11 +743,18 @@ inline_outb_tun_pkt_process(const struct rte_ipsec_session *ss,
>>   			dr[i - k] = i;
>>   			rte_errno = -rc;
>>   		}
>> +
>> +		/**
>> +		 * If packet is using tso, increment sqn by the number of
>> +		 * segments for	packet
>> +		 */
>> +		if  (mb[i]->ol_flags & (PKT_TX_TCP_SEG | PKT_TX_UDP_SEG))
>> +			sqn += nb_segs[i] - 1;
>>   	}
>>
>>   	/* copy not processed mbufs beyond good ones */
>> -	if (k != n && k != 0)
>> -		move_bad_mbufs(mb, dr, n, n - k);
>> +	if (k != num && k != 0)
>> +		move_bad_mbufs(mb, dr, num, num - k);
>>
>>   	inline_outb_mbuf_prepare(ss, mb, k);
>>   	return k;
>> @@ -710,23 +769,30 @@ inline_outb_trs_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_sqn, nb_sqn_alloc;
>>   	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;
>>
>> -	n = num;
>> -	sqn = esn_outb_update_sqn(sa, &n);
>> -	if (n != num)
>> +	/* Calculate number of sequence numbers required */
>> +	for (i = 0, nb_sqn = 0; i != num; i++) {
>> +		nb_segs[i] = esn_outb_nb_segments(sa, mb[i]);
>> +		nb_sqn += nb_segs[i];
>> +	}
>> +
>> +	nb_sqn_alloc = nb_sqn;
>> +	sqn = esn_outb_update_sqn(sa, &nb_sqn_alloc);
>> +	if (nb_sqn_alloc != nb_sqn)
>>   		rte_errno = EOVERFLOW;
>>
>>   	k = 0;
>> -	for (i = 0; i != n; i++) {
>> +	for (i = 0; i != num; i++) {
>>
>>   		sqc = rte_cpu_to_be_64(sqn + i);
>>   		gen_iv(iv, sqc);
>> @@ -741,11 +807,18 @@ inline_outb_trs_pkt_process(const struct rte_ipsec_session *ss,
>>   			dr[i - k] = i;
>>   			rte_errno = -rc;
>>   		}
>> +
>> +		/**
>> +		 * If packet is using tso, increment sqn by the number of
>> +		 * segments for	packet
>> +		 */
>> +		if  (mb[i]->ol_flags & (PKT_TX_TCP_SEG | PKT_TX_UDP_SEG))
>> +			sqn += nb_segs[i] - 1;
>>   	}
>>
>>   	/* copy not processed mbufs beyond good ones */
>> -	if (k != n && k != 0)
>> -		move_bad_mbufs(mb, dr, n, n - k);
>> +	if (k != num && k != 0)
>> +		move_bad_mbufs(mb, dr, num, num - k);
>>
>>   	inline_outb_mbuf_prepare(ss, mb, k);
>>   	return k;
>> diff --git a/lib/ipsec/iph.h b/lib/ipsec/iph.h
>> index 861f16905a..2d223199ac 100644
>> --- a/lib/ipsec/iph.h
>> +++ b/lib/ipsec/iph.h
>> @@ -6,6 +6,8 @@
>>   #define _IPH_H_
>>
>>   #include <rte_ip.h>
>> +#include <rte_udp.h>
>> +#include <rte_tcp.h>
>>
>>   /**
>>    * @file iph.h
>> @@ -39,8 +41,8 @@ insert_esph(char *np, char *op, uint32_t hlen)
>>
>>   /* update original ip header fields for transport case */
>>   static inline int
>> -update_trs_l3hdr(const struct rte_ipsec_sa *sa, void *p, uint32_t plen,
>> -		uint32_t l2len, uint32_t l3len, uint8_t proto)
>> +update_trs_l34hdrs(const struct rte_ipsec_sa *sa, void *p, uint32_t plen,
>> +		uint32_t l2len, uint32_t l3len, uint8_t proto, uint8_t tso)
> Hmm... why to change name of the function?
>
>>   {
>>   	int32_t rc;
>>
>> @@ -51,6 +53,10 @@ update_trs_l3hdr(const struct rte_ipsec_sa *sa, void *p, uint32_t plen,
>>   		v4h = p;
>>   		rc = v4h->next_proto_id;
>>   		v4h->next_proto_id = proto;
>> +		if (tso) {
>> +			v4h->hdr_checksum = 0;
>> +			v4h->total_length = 0;
> total_len will be overwritten unconditionally at next line below.
>
> Another question - why it is necessary?
> Is it HW specific requirment or ... ?
It looks wrong I will rewrite this.
>
>
>> +		}
>>   		v4h->total_length = rte_cpu_to_be_16(plen - l2len);
>
>>   	/* IPv6 */
>>   	} else {
>> diff --git a/lib/ipsec/sa.c b/lib/ipsec/sa.c
>> index 720e0f365b..2ecbbce0a4 100644
>> --- a/lib/ipsec/sa.c
>> +++ b/lib/ipsec/sa.c
>> @@ -565,6 +565,12 @@ rte_ipsec_sa_init(struct rte_ipsec_sa *sa, const struct rte_ipsec_sa_prm *prm,
>>   	sa->type = type;
>>   	sa->size = sz;
>>
>> +
>> +	if (prm->ipsec_xform.options.tso == 1) {
>> +		sa->tso.enabled = 1;
>> +		sa->tso.mss = prm->ipsec_xform.mss;
>> +	}
>> +
>>   	/* check for ESN flag */
>>   	sa->sqn_mask = (prm->ipsec_xform.options.esn == 0) ?
>>   		UINT32_MAX : UINT64_MAX;
>> diff --git a/lib/ipsec/sa.h b/lib/ipsec/sa.h
>> index 107ebd1519..5e237f3525 100644
>> --- a/lib/ipsec/sa.h
>> +++ b/lib/ipsec/sa.h
>> @@ -113,6 +113,10 @@ struct rte_ipsec_sa {
>>   	uint8_t iv_len;
>>   	uint8_t pad_align;
>>   	uint8_t tos_mask;
>> +	struct {
>> +		uint8_t enabled:1;
>> +		uint16_t mss;
>> +	} tso;
> Wouldn't one field be enough?
> uint16_t tso_mss;
> And it it is zero, then tso is disabled.
> In fact, do we need it at all?
> Wouldn't it be better to request user to fill mbuf->tso_segsz properly for us?

We added an option to rte_security_ipsec_sa_options to allow the user to 
enable TSO per SA and specify the MSS in the sessions parameters.

We can request user to fill mbuf->tso_segsz, but with this patch we are 
doing it for the user.

>
>>   	/* template for tunnel header */
>>   	uint8_t hdr[IPSEC_MAX_HDR_SIZE];
>> --
>> 2.25.1