[dpdk-dev] [PATCH v2 10/13] mbuf: generic support for TCP segmentation offload
Ananyev, Konstantin
konstantin.ananyev at intel.com
Tue Nov 18 00:33:30 CET 2014
> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Olivier Matz
> Sent: Friday, November 14, 2014 5:03 PM
> To: dev at dpdk.org
> Cc: jigsaw at gmail.com
> Subject: [dpdk-dev] [PATCH v2 10/13] mbuf: generic support for TCP segmentation offload
>
> Some of the NICs supported by DPDK have a possibility to accelerate TCP
> traffic by using segmentation offload. The application prepares a packet
> with valid TCP header with size up to 64K and deleguates the
> segmentation to the NIC.
>
> Implement the generic part of TCP segmentation offload in rte_mbuf. It
> introduces 2 new fields in rte_mbuf: l4_len (length of L4 header in bytes)
> and tso_segsz (MSS of packets).
>
> To delegate the TCP segmentation to the hardware, the user has to:
>
> - set the PKT_TX_TCP_SEG flag in mbuf->ol_flags (this flag implies
> PKT_TX_TCP_CKSUM)
> - set PKT_TX_IP_CKSUM if it's IPv4, and set the IP checksum to 0 in
> the packet
> - fill the mbuf offload information: l2_len, l3_len, l4_len, tso_segsz
> - calculate the pseudo header checksum without taking ip_len in account,
> and set it in the TCP header, for instance by using
> rte_ipv4_phdr_cksum(ip_hdr, ol_flags)
>
> The API is inspired from ixgbe hardware (the next commit adds the
> support for ixgbe), but it seems generic enough to be used for other
> hw/drivers in the future.
>
> This commit also reworks the way l2_len and l3_len are used in igb
> and ixgbe drivers as the l2_l3_len is not available anymore in mbuf.
>
> Signed-off-by: Mirek Walukiewicz <miroslaw.walukiewicz at intel.com>
> Signed-off-by: Olivier Matz <olivier.matz at 6wind.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev at intel.com>
> ---
> app/test-pmd/testpmd.c | 2 +-
> examples/ipv4_multicast/main.c | 2 +-
> lib/librte_mbuf/rte_mbuf.c | 1 +
> lib/librte_mbuf/rte_mbuf.h | 44 +++++++++++++++++++++++----------------
> lib/librte_net/rte_ip.h | 39 +++++++++++++++++++++++++++-------
> lib/librte_pmd_e1000/igb_rxtx.c | 11 +++++++++-
> lib/librte_pmd_ixgbe/ixgbe_rxtx.c | 11 +++++++++-
> 7 files changed, 81 insertions(+), 29 deletions(-)
>
> diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c
> index 12adafa..632a993 100644
> --- a/app/test-pmd/testpmd.c
> +++ b/app/test-pmd/testpmd.c
> @@ -408,7 +408,7 @@ testpmd_mbuf_ctor(struct rte_mempool *mp,
> mb->ol_flags = 0;
> mb->data_off = RTE_PKTMBUF_HEADROOM;
> mb->nb_segs = 1;
> - mb->l2_l3_len = 0;
> + mb->tx_offload = 0;
> mb->vlan_tci = 0;
> mb->hash.rss = 0;
> }
> diff --git a/examples/ipv4_multicast/main.c b/examples/ipv4_multicast/main.c
> index 590d11a..80c5140 100644
> --- a/examples/ipv4_multicast/main.c
> +++ b/examples/ipv4_multicast/main.c
> @@ -302,7 +302,7 @@ mcast_out_pkt(struct rte_mbuf *pkt, int use_clone)
> /* copy metadata from source packet*/
> hdr->port = pkt->port;
> hdr->vlan_tci = pkt->vlan_tci;
> - hdr->l2_l3_len = pkt->l2_l3_len;
> + hdr->tx_offload = pkt->tx_offload;
> hdr->hash = pkt->hash;
>
> hdr->ol_flags = pkt->ol_flags;
> diff --git a/lib/librte_mbuf/rte_mbuf.c b/lib/librte_mbuf/rte_mbuf.c
> index 5cd9137..75295c8 100644
> --- a/lib/librte_mbuf/rte_mbuf.c
> +++ b/lib/librte_mbuf/rte_mbuf.c
> @@ -238,6 +238,7 @@ const char *rte_get_tx_ol_flag_name(uint64_t mask)
> case PKT_TX_UDP_CKSUM: return "PKT_TX_UDP_CKSUM";
> case PKT_TX_IEEE1588_TMST: return "PKT_TX_IEEE1588_TMST";
> case PKT_TX_VXLAN_CKSUM: return "PKT_TX_VXLAN_CKSUM";
> + case PKT_TX_TCP_SEG: return "PKT_TX_TCP_SEG";
> default: return NULL;
> }
> }
> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
> index 3c8e825..9f44d08 100644
> --- a/lib/librte_mbuf/rte_mbuf.h
> +++ b/lib/librte_mbuf/rte_mbuf.h
> @@ -127,6 +127,20 @@ extern "C" {
>
> #define PKT_TX_VXLAN_CKSUM (1ULL << 50) /**< TX checksum of VXLAN computed by NIC */
>
> +/**
> + * TCP segmentation offload. To enable this offload feature for a
> + * packet to be transmitted on hardware supporting TSO:
> + * - set the PKT_TX_TCP_SEG flag in mbuf->ol_flags (this flag implies
> + * PKT_TX_TCP_CKSUM)
> + * - if it's IPv4, set the PKT_TX_IP_CKSUM flag and write the IP checksum
> + * to 0 in the packet
> + * - fill the mbuf offload information: l2_len, l3_len, l4_len, tso_segsz
> + * - calculate the pseudo header checksum without taking ip_len in accound,
> + * and set it in the TCP header. Refer to rte_ipv4_phdr_cksum() and
> + * rte_ipv6_phdr_cksum() that can be used as helpers.
> + */
> +#define PKT_TX_TCP_SEG (1ULL << 49)
> +
> /* Use final bit of flags to indicate a control mbuf */
> #define CTRL_MBUF_FLAG (1ULL << 63) /**< Mbuf contains control data */
>
> @@ -228,22 +242,18 @@ struct rte_mbuf {
>
> /* fields to support TX offloads */
> union {
> - uint16_t l2_l3_len; /**< combined l2/l3 lengths as single var */
> + uint64_t tx_offload; /**< combined for easy fetch */
> struct {
> - uint16_t l3_len:9; /**< L3 (IP) Header Length. */
> - uint16_t l2_len:7; /**< L2 (MAC) Header Length. */
> - };
> - };
> + uint64_t l2_len:7; /**< L2 (MAC) Header Length. */
> + uint64_t l3_len:9; /**< L3 (IP) Header Length. */
> + uint64_t l4_len:8; /**< L4 (TCP/UDP) Header Length. */
> + uint64_t tso_segsz:16; /**< TCP TSO segment size */
>
> - /* fields for TX offloading of tunnels */
> - union {
> - uint16_t inner_l2_l3_len;
> - /**< combined inner l2/l3 lengths as single var */
> - struct {
> - uint16_t inner_l3_len:9;
> - /**< inner L3 (IP) Header Length. */
> - uint16_t inner_l2_len:7;
> - /**< inner L2 (MAC) Header Length. */
> + /* fields for TX offloading of tunnels */
> + uint64_t inner_l3_len:9; /**< inner L3 (IP) Hdr Length. */
> + uint64_t inner_l2_len:7; /**< inner L2 (MAC) Hdr Length. */
> +
> + /* uint64_t unused:8; */
> };
> };
> } __rte_cache_aligned;
> @@ -595,8 +605,7 @@ static inline void rte_pktmbuf_reset(struct rte_mbuf *m)
> {
> m->next = NULL;
> m->pkt_len = 0;
> - m->l2_l3_len = 0;
> - m->inner_l2_l3_len = 0;
> + m->tx_offload = 0;
> m->vlan_tci = 0;
> m->nb_segs = 1;
> m->port = 0xff;
> @@ -665,8 +674,7 @@ static inline void rte_pktmbuf_attach(struct rte_mbuf *mi, struct rte_mbuf *md)
> mi->data_len = md->data_len;
> mi->port = md->port;
> mi->vlan_tci = md->vlan_tci;
> - mi->l2_l3_len = md->l2_l3_len;
> - mi->inner_l2_l3_len = md->inner_l2_l3_len;
> + mi->tx_offload = md->tx_offload;
> mi->hash = md->hash;
>
> mi->next = NULL;
> diff --git a/lib/librte_net/rte_ip.h b/lib/librte_net/rte_ip.h
> index 9cfca7f..1fafa73 100644
> --- a/lib/librte_net/rte_ip.h
> +++ b/lib/librte_net/rte_ip.h
> @@ -80,6 +80,7 @@
>
> #include <rte_memcpy.h>
> #include <rte_byteorder.h>
> +#include <rte_mbuf.h>
>
> #ifdef __cplusplus
> extern "C" {
> @@ -308,13 +309,21 @@ rte_ipv4_cksum(const struct ipv4_hdr *ipv4_hdr)
> *
> * The checksum field must be set to 0 by the caller.
> *
> + * Depending on the ol_flags, the pseudo-header checksum expected by the
> + * drivers is not the same. For instance, when TSO is enabled, the IP
> + * payload length must not be included in the packet.
> + *
> + * When ol_flags is 0, it computes the standard pseudo-header checksum.
> + *
> * @param ipv4_hdr
> * The pointer to the contiguous IPv4 header.
> + * @param ol_flags
> + * The ol_flags of the associated mbuf.
> * @return
> * The non-complemented checksum to set in the L4 header.
> */
> static inline uint16_t
> -rte_ipv4_phdr_cksum(const struct ipv4_hdr *ipv4_hdr)
> +rte_ipv4_phdr_cksum(const struct ipv4_hdr *ipv4_hdr, uint64_t ol_flags)
> {
> struct ipv4_psd_header {
> uint32_t src_addr; /* IP address of source host. */
> @@ -328,9 +337,13 @@ rte_ipv4_phdr_cksum(const struct ipv4_hdr *ipv4_hdr)
> psd_hdr.dst_addr = ipv4_hdr->dst_addr;
> psd_hdr.zero = 0;
> psd_hdr.proto = ipv4_hdr->next_proto_id;
> - psd_hdr.len = rte_cpu_to_be_16(
> - (uint16_t)(rte_be_to_cpu_16(ipv4_hdr->total_length)
> - - sizeof(struct ipv4_hdr)));
> + if (ol_flags & PKT_TX_TCP_SEG) {
> + psd_hdr.len = 0;
> + } else {
> + psd_hdr.len = rte_cpu_to_be_16(
> + (uint16_t)(rte_be_to_cpu_16(ipv4_hdr->total_length)
> + - sizeof(struct ipv4_hdr)));
> + }
> return rte_raw_cksum((const char *)&psd_hdr, sizeof(psd_hdr));
> }
>
> @@ -357,7 +370,7 @@ rte_ipv4_udptcp_cksum(const struct ipv4_hdr *ipv4_hdr, const void *l4_hdr)
> sizeof(struct ipv4_hdr);
>
> cksum = rte_raw_cksum(l4_hdr, l4_len);
> - cksum += rte_ipv4_phdr_cksum(ipv4_hdr);
> + cksum += rte_ipv4_phdr_cksum(ipv4_hdr, 0);
>
> cksum = ((cksum & 0xffff0000) >> 16) + (cksum & 0xffff);
> cksum = (~cksum) & 0xffff;
> @@ -382,13 +395,21 @@ struct ipv6_hdr {
> /**
> * Process the pseudo-header checksum of an IPv6 header.
> *
> + * Depending on the ol_flags, the pseudo-header checksum expected by the
> + * drivers is not the same. For instance, when TSO is enabled, the IPv6
> + * payload length must not be included in the packet.
> + *
> + * When ol_flags is 0, it computes the standard pseudo-header checksum.
> + *
> * @param ipv6_hdr
> * The pointer to the contiguous IPv6 header.
> + * @param ol_flags
> + * The ol_flags of the associated mbuf.
> * @return
> * The non-complemented checksum to set in the L4 header.
> */
> static inline uint16_t
> -rte_ipv6_phdr_cksum(const struct ipv6_hdr *ipv6_hdr)
> +rte_ipv6_phdr_cksum(const struct ipv6_hdr *ipv6_hdr, uint64_t ol_flags)
> {
> struct ipv6_psd_header {
> uint8_t src_addr[16]; /* IP address of source host. */
> @@ -400,7 +421,11 @@ rte_ipv6_phdr_cksum(const struct ipv6_hdr *ipv6_hdr)
> rte_memcpy(&psd_hdr.src_addr, ipv6_hdr->src_addr,
> sizeof(ipv6_hdr->src_addr) + sizeof(ipv6_hdr->dst_addr));
> psd_hdr.proto = (ipv6_hdr->proto << 24);
> - psd_hdr.len = ipv6_hdr->payload_len;
> + if (ol_flags & PKT_TX_TCP_SEG) {
> + psd_hdr.len = 0;
> + } else {
> + psd_hdr.len = ipv6_hdr->payload_len;
> + }
>
> return rte_raw_cksum((const char *)&psd_hdr, sizeof(psd_hdr));
> }
> diff --git a/lib/librte_pmd_e1000/igb_rxtx.c b/lib/librte_pmd_e1000/igb_rxtx.c
> index 433c616..848d5d1 100644
> --- a/lib/librte_pmd_e1000/igb_rxtx.c
> +++ b/lib/librte_pmd_e1000/igb_rxtx.c
> @@ -367,6 +367,13 @@ eth_igb_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
> struct rte_mbuf *tx_pkt;
> struct rte_mbuf *m_seg;
> union igb_vlan_macip vlan_macip_lens;
> + union {
> + uint16_t u16;
> + struct {
> + uint16_t l3_len:9;
> + uint16_t l2_len:7;
> + };
> + } l2_l3_len;
> uint64_t buf_dma_addr;
> uint32_t olinfo_status;
> uint32_t cmd_type_len;
> @@ -404,8 +411,10 @@ eth_igb_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
> tx_last = (uint16_t) (tx_id + tx_pkt->nb_segs - 1);
>
> ol_flags = tx_pkt->ol_flags;
> + l2_l3_len.l2_len = tx_pkt->l2_len;
> + l2_l3_len.l3_len = tx_pkt->l3_len;
> vlan_macip_lens.f.vlan_tci = tx_pkt->vlan_tci;
> - vlan_macip_lens.f.l2_l3_len = tx_pkt->l2_l3_len;
> + vlan_macip_lens.f.l2_l3_len = l2_l3_len.u16;
> tx_ol_req = ol_flags & IGB_TX_OFFLOAD_MASK;
>
> /* If a Context Descriptor need be built . */
> diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
> index ca35db2..2df3385 100644
> --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
> +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
> @@ -546,6 +546,13 @@ ixgbe_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
> struct rte_mbuf *tx_pkt;
> struct rte_mbuf *m_seg;
> union ixgbe_vlan_macip vlan_macip_lens;
> + union {
> + uint16_t u16;
> + struct {
> + uint16_t l3_len:9;
> + uint16_t l2_len:7;
> + };
> + } l2_l3_len;
> uint64_t buf_dma_addr;
> uint32_t olinfo_status;
> uint32_t cmd_type_len;
> @@ -588,8 +595,10 @@ ixgbe_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
> /* If hardware offload required */
> tx_ol_req = ol_flags & IXGBE_TX_OFFLOAD_MASK;
> if (tx_ol_req) {
> + l2_l3_len.l2_len = tx_pkt->l2_len;
> + l2_l3_len.l3_len = tx_pkt->l3_len;
> vlan_macip_lens.f.vlan_tci = tx_pkt->vlan_tci;
> - vlan_macip_lens.f.l2_l3_len = tx_pkt->l2_l3_len;
> + vlan_macip_lens.f.l2_l3_len = l2_l3_len.u16;
>
> /* If new context need be built or reuse the exist ctx. */
> ctx = what_advctx_update(txq, tx_ol_req,
> --
> 2.1.0
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