Hi Xiao,
> -----Original Message-----
> From: Wang, Xiao W
> Sent: Thursday, June 21, 2018 4:25 PM
> To: Hu, Jiayu <jiayu...@intel.com>; dev@dpdk.org
> Cc: Ananyev, Konstantin <konstantin.anan...@intel.com>; Zhang, Yuwei1
> <yuwei1.zh...@intel.com>; Iremonger, Bernard
> <bernard.iremon...@intel.com>; Hu, Jiayu <jiayu...@intel.com>
> Subject: RE: [dpdk-dev] [PATCH v2 1/3] gso: support UDP/IPv4
> fragmentation
>
> Hi,
>
> > -----Original Message-----
> > From: dev [mailto:dev-boun...@dpdk.org] On Behalf Of Jiayu Hu
> > Sent: Sunday, June 17, 2018 11:13 AM
> > To: dev@dpdk.org
> > Cc: Ananyev, Konstantin <konstantin.anan...@intel.com>; Zhang, Yuwei1
> > <yuwei1.zh...@intel.com>; Iremonger, Bernard
> > <bernard.iremon...@intel.com>; Hu, Jiayu <jiayu...@intel.com>
> > Subject: [dpdk-dev] [PATCH v2 1/3] gso: support UDP/IPv4 fragmentation
> >
> > This patch adds GSO support for UDP/IPv4 packets. Supported packets
> > may include a single VLAN tag. UDP/IPv4 GSO doesn't check if input
> > packets have correct checksums, and doesn't update checksums for
> > output packets (the responsibility for this lies with the application).
> > Additionally, UDP/IPv4 GSO doesn't process IP fragmented packets.
> >
> > UDP/IPv4 GSO uses two chained MBUFs, one direct MBUF and one indrect
> > MBUF, to organize an output packet. The direct MBUF stores the packet
> > header, while the indirect mbuf simply points to a location within the
> > original packet's payload. Consequently, use of UDP GSO requires
> > multi-segment MBUF support in the TX functions of the NIC driver.
> >
> > If a packet is GSO'd, UDP/IPv4 GSO reduces its MBUF refcnt by 1. As a
> > result, when all of its GSOed segments are freed, the packet is freed
> > automatically.
> >
> > Signed-off-by: Jiayu Hu <jiayu...@intel.com>
> > ---
> > lib/librte_gso/Makefile | 1 +
> > lib/librte_gso/gso_common.h | 3 ++
> > lib/librte_gso/gso_udp4.c | 81
> > +++++++++++++++++++++++++++++++++++++++++++++
> > lib/librte_gso/gso_udp4.h | 42 +++++++++++++++++++++++
> > lib/librte_gso/rte_gso.c | 24 +++++++++++---
> > lib/librte_gso/rte_gso.h | 6 +++-
> > 6 files changed, 151 insertions(+), 6 deletions(-)
> > create mode 100644 lib/librte_gso/gso_udp4.c
> > create mode 100644 lib/librte_gso/gso_udp4.h
> >
> > diff --git a/lib/librte_gso/Makefile b/lib/librte_gso/Makefile
> > index 3648ec0..1fac53a 100644
> > --- a/lib/librte_gso/Makefile
> > +++ b/lib/librte_gso/Makefile
> > @@ -19,6 +19,7 @@ SRCS-$(CONFIG_RTE_LIBRTE_GSO) += rte_gso.c
> > SRCS-$(CONFIG_RTE_LIBRTE_GSO) += gso_common.c
> > SRCS-$(CONFIG_RTE_LIBRTE_GSO) += gso_tcp4.c
> > SRCS-$(CONFIG_RTE_LIBRTE_GSO) += gso_tunnel_tcp4.c
> > +SRCS-$(CONFIG_RTE_LIBRTE_GSO) += gso_udp4.c
> >
>
> meson should be updated accordingly.
Thanks a lot. Update later.
>
> > # install this header file
> > SYMLINK-$(CONFIG_RTE_LIBRTE_GSO)-include += rte_gso.h
> > diff --git a/lib/librte_gso/gso_common.h b/lib/librte_gso/gso_common.h
> > index 5ca5974..6cd764f 100644
> > --- a/lib/librte_gso/gso_common.h
> > +++ b/lib/librte_gso/gso_common.h
> > @@ -31,6 +31,9 @@
> > (PKT_TX_TCP_SEG | PKT_TX_IPV4 | PKT_TX_OUTER_IPV4 |
> \
> > PKT_TX_TUNNEL_GRE))
> >
> > +#define IS_IPV4_UDP(flag) (((flag) & (PKT_TX_UDP_SEG | PKT_TX_IPV4))
> == \
> > + (PKT_TX_UDP_SEG | PKT_TX_IPV4))
> > +
> > /**
> > * Internal function which updates the UDP header of a packet, following
> > * segmentation. This is required to update the header's datagram length
> field.
> > diff --git a/lib/librte_gso/gso_udp4.c b/lib/librte_gso/gso_udp4.c
> > new file mode 100644
> > index 0000000..a3db329
> > --- /dev/null
> > +++ b/lib/librte_gso/gso_udp4.c
> > @@ -0,0 +1,81 @@
> > +/* SPDX-License-Identifier: BSD-3-Clause
> > + * Copyright(c) 2018 Intel Corporation
> > + */
> > +
> > +#include "gso_common.h"
> > +#include "gso_udp4.h"
> > +
> > +#define IPV4_HDR_MF_BIT (1U << 13)
> > +
> > +static inline void
> > +update_ipv4_udp_headers(struct rte_mbuf *pkt, struct rte_mbuf **segs,
> > + uint16_t nb_segs)
> > +{
> > + struct ipv4_hdr *ipv4_hdr;
> > + uint16_t frag_offset = 0, is_mf;
> > + uint16_t l2_hdrlen = pkt->l2_len, l3_hdrlen = pkt->l3_len;
> > + uint16_t tail_idx = nb_segs - 1, length, i;
> > +
> > + /*
> > + * Update IP header fields for output segments. Specifically,
> > + * keep the same IP id, update fragment offset and total
> > + * length.
> > + */
> > + for (i = 0; i < nb_segs; i++) {
> > + ipv4_hdr = (struct ipv4_hdr *)(rte_pktmbuf_mtod(segs[i],
> > + char *) + l2_hdrlen);
>
> You could use rte_pktmbuf_mtod_offset to simplify the code.
Yes, you are right. Update later.
>
> > + length = segs[i]->pkt_len - l2_hdrlen;
> > + ipv4_hdr->total_length = rte_cpu_to_be_16(length);
> > +
> > + is_mf = i < tail_idx ? IPV4_HDR_MF_BIT : 0;
> > + ipv4_hdr->fragment_offset =
> > + rte_cpu_to_be_16(frag_offset | is_mf);
> > + frag_offset += ((length - l3_hdrlen) >> 3);
> > + }
> > +}
> > +
> > +int
> > +gso_udp4_segment(struct rte_mbuf *pkt,
> > + uint16_t gso_size,
> > + struct rte_mempool *direct_pool,
> > + struct rte_mempool *indirect_pool,
> > + struct rte_mbuf **pkts_out,
> > + uint16_t nb_pkts_out)
> > +{
> > + struct ipv4_hdr *ipv4_hdr;
> > + uint16_t pyld_unit_size, hdr_offset;
> > + uint16_t frag_off;
> > + int ret;
> > +
> > + /* Don't process the fragmented packet */
> > + ipv4_hdr = (struct ipv4_hdr *)(rte_pktmbuf_mtod(pkt, char *) +
> > + pkt->l2_len);
>
> Ditto.
>
> BRs,
> Xiao
Thanks,
Jiayu
