> -----Original Message-----
> From: Olivier Matz [mailto:olivier.matz at 6wind.com]
> Sent: Monday, November 10, 2014 11:59 PM
> To: dev at dpdk.org
> Cc: olivier.matz at 6wind.com; Walukiewicz, Miroslaw; Liu, Jijiang; Liu, Yong;
> jigsaw at gmail.com; Richardson, Bruce; Ananyev, Konstantin
> Subject: [PATCH 07/12] 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 and set it in the TCP header,
> as required when doing hardware TCP checksum offload
>
> 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>
> ---
> app/test-pmd/testpmd.c | 3 ++-
> examples/ipv4_multicast/main.c | 3 ++-
> lib/librte_mbuf/rte_mbuf.h | 44
> +++++++++++++++++++++++----------------
> lib/librte_pmd_e1000/igb_rxtx.c | 11 +++++++++-
> lib/librte_pmd_ixgbe/ixgbe_rxtx.c | 11 +++++++++-
> 5 files changed, 50 insertions(+), 22 deletions(-)
>
> diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c index
> 12adafa..a831e31 100644
> --- a/app/test-pmd/testpmd.c
> +++ b/app/test-pmd/testpmd.c
> @@ -408,7 +408,8 @@ 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->l2_len = 0;
> + mb->l3_len = 0;
The mb->inner_l2_len and mb->inner_l3_len are missed here; I also can add
them later.
> mb->vlan_tci = 0;
> mb->hash.rss = 0;
> }
> diff --git a/examples/ipv4_multicast/main.c b/examples/ipv4_multicast/main.c
> index de5e6be..a31d43d 100644
> --- a/examples/ipv4_multicast/main.c
> +++ b/examples/ipv4_multicast/main.c
> @@ -302,7 +302,8 @@ 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->l2_len = pkt->l2_len;
> + hdr->l3_len = pkt->l3_len;
The mb->inner_l2_len and mb->inner_l3_len are missed here, too.
> hdr->hash = pkt->hash;
>
> hdr->ol_flags = pkt->ol_flags;
> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h index
> bcd8996..f76b768 100644
> --- a/lib/librte_mbuf/rte_mbuf.h
> +++ b/lib/librte_mbuf/rte_mbuf.h
> @@ -126,6 +126,19 @@ 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 and set it in the TCP header,
> + * as required when doing hardware TCP checksum offload
> + */
> +#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 */
>
> @@ -185,6 +198,7 @@ static inline 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;
> }
> }
> @@ -264,22 +278,18 @@ 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 */
> + uint16_t inner_l3_len:9; /**< inner L3 (IP) Hdr Length.
> */
> + uint16_t inner_l2_len:7; /**< inner L2 (MAC) Hdr
> Length. */
> +
> + /* uint64_t unused:8; */
> };
> };
> } __rte_cache_aligned;
> @@ -631,8 +641,7 @@ 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;
> @@ -701,8 +710,7 @@ 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_pmd_e1000/igb_rxtx.c b/lib/librte_pmd_e1000/igb_rxtx.c
> index dbf5074..0a9447e 100644
> --- a/lib/librte_pmd_e1000/igb_rxtx.c
> +++ b/lib/librte_pmd_e1000/igb_rxtx.c
> @@ -361,6 +361,13 @@ 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;
> @@ -398,8 +405,10 @@ 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 & (PKT_TX_VLAN_PKT | PKT_TX_IP_CKSUM
> |
> PKT_TX_L4_MASK);
>
> diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
> b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
> index 70ca254..54a0fc1 100644
> --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
> +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
> @@ -540,6 +540,13 @@ 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;
> @@ -583,8 +590,10 @@ ixgbe_xmit_pkts(void *tx_queue, struct rte_mbuf
> **tx_pkts,
> tx_ol_req = ol_flags & (PKT_TX_VLAN_PKT | PKT_TX_IP_CKSUM
> |
> PKT_TX_L4_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
