Hi,
Please find some comments below.
> -----Original Message-----
> From: dev [mailto:dev-boun...@dpdk.org] On Behalf Of Jiayu Hu
> Sent: Friday, June 22, 2018 8:54 AM
> To: dev@dpdk.org
> Cc: xiao.w.w...@intel.com; konstantin.anan...@intel.com;
> yuwei1.zh...@intel.com; bernard.iremon...@intel.com; Thomas Monjalon
> <tho...@monjalon.net>; Jiayu Hu <jiayu...@intel.com>
> Subject: [dpdk-dev] [PATCH v3 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/meson.build | 2 +-
> lib/librte_gso/rte_gso.c | 24 +++++++++++---
> lib/librte_gso/rte_gso.h | 6 +++-
> 7 files changed, 152 insertions(+), 7 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-$(CONFIG_RTE_LIBRTE_GSO) += gso_udp4.c
>
> # install this header file
> SYMLINK-$(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..927dee1
> --- /dev/null
> +++ b/lib/librte_gso/gso_udp4.c
File gso_upd4.c could be very similar to file gso_tcp4.c and that would avoid
code duplication.
In a unified file you could use a tcp vs. udp flag to distinguish between them
when necessary.
The files are short (~75 lines) so it is not a critical issue.
> @@ -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 = rte_pktmbuf_mtod_offset(segs[i], struct ipv4_hdr
> *,
> + l2_hdrlen);
> + 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 = rte_pktmbuf_mtod_offset(pkt, struct ipv4_hdr *,
> + pkt->l2_len);
> + frag_off = rte_be_to_cpu_16(ipv4_hdr->fragment_offset);
> + if (unlikely(IS_FRAGMENTED(frag_off))) {
> + pkts_out[0] = pkt;
> + return 1;
> + }
> +
> + /*
> + * UDP fragmentation is the same as IP fragmentation.
> + * Except the first one, other output packets just have l2
> + * and l3 headers.
> + */
> + hdr_offset = pkt->l2_len + pkt->l3_len;
> +
> + /* Don't process the packet without data. */
> + if (unlikely(hdr_offset + pkt->l4_len >= pkt->pkt_len)) {
> + pkts_out[0] = pkt;
> + return 1;
> + }
> +
> + pyld_unit_size = gso_size - hdr_offset;
> +
> + /* Segment the payload */
> + ret = gso_do_segment(pkt, hdr_offset, pyld_unit_size, direct_pool,
> + indirect_pool, pkts_out, nb_pkts_out);
> + if (ret > 1)
> + update_ipv4_udp_headers(pkt, pkts_out, ret);
> +
> + return ret;
> +}
> diff --git a/lib/librte_gso/gso_udp4.h b/lib/librte_gso/gso_udp4.h new file
> mode 100644 index 0000000..b2a2908
File gso_upd4.h is almost identical to file gso_tcp4.h so both files (although
short ~40 lines) could have been unified into one file.
> --- /dev/null
> +++ b/lib/librte_gso/gso_udp4.h
> @@ -0,0 +1,42 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright(c) 2018 Intel Corporation
> + */
> +
> +#ifndef _GSO_UDP4_H_
> +#define _GSO_UDP4_H_
> +
> +#include <stdint.h>
> +#include <rte_mbuf.h>
> +
> +/**
> + * Segment an UDP/IPv4 packet. This function doesn't check if the input
> + * packet has correct checksums, and doesn't update checksums for
> +output
> + * GSO segments. Furthermore, it doesn't process IP fragment packets.
> + *
> + * @param pkt
> + * The packet mbuf to segment.
> + * @param gso_size
> + * The max length of a GSO segment, measured in bytes.
> + * @param direct_pool
> + * MBUF pool used for allocating direct buffers for output segments.
> + * @param indirect_pool
> + * MBUF pool used for allocating indirect buffers for output segments.
> + * @param pkts_out
> + * Pointer array used to store the MBUF addresses of output GSO
> + * segments, when the function succeeds. If the memory space in
> + * pkts_out is insufficient, it fails and returns -EINVAL.
> + * @param nb_pkts_out
> + * The max number of items that 'pkts_out' can keep.
> + *
> + * @return
> + * - The number of GSO segments filled in pkts_out on success.
> + * - Return -ENOMEM if run out of memory in MBUF pools.
> + * - Return -EINVAL for invalid parameters.
> + */
> +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);
> +#endif
> diff --git a/lib/librte_gso/meson.build b/lib/librte_gso/meson.build index
> 056534f..ad8dd85 100644
> --- a/lib/librte_gso/meson.build
> +++ b/lib/librte_gso/meson.build
> @@ -1,7 +1,7 @@
> # SPDX-License-Identifier: BSD-3-Clause # Copyright(c) 2017 Intel
> Corporation
>
> -sources = files('gso_common.c', 'gso_tcp4.c',
> +sources = files('gso_common.c', 'gso_tcp4.c', 'gso_udp4.c',
> 'gso_tunnel_tcp4.c', 'rte_gso.c')
> headers = files('rte_gso.h')
> deps += ['ethdev']
> diff --git a/lib/librte_gso/rte_gso.c b/lib/librte_gso/rte_gso.c index
> a44e3d4..751b5b6 100644
> --- a/lib/librte_gso/rte_gso.c
> +++ b/lib/librte_gso/rte_gso.c
> @@ -11,6 +11,17 @@
> #include "gso_common.h"
> #include "gso_tcp4.h"
> #include "gso_tunnel_tcp4.h"
> +#include "gso_udp4.h"
> +
> +#define ILLEGAL_UDP_GSO_CTX(ctx) \
> + ((((ctx)->gso_types & DEV_TX_OFFLOAD_UDP_TSO) == 0) || \
> + (ctx)->gso_size < RTE_GSO_UDP_SEG_SIZE_MIN)
> +
> +#define ILLEGAL_TCP_GSO_CTX(ctx) \
> + ((((ctx)->gso_types & (DEV_TX_OFFLOAD_TCP_TSO | \
> + DEV_TX_OFFLOAD_VXLAN_TNL_TSO | \
> + DEV_TX_OFFLOAD_GRE_TNL_TSO)) == 0) || \
> + (ctx)->gso_size < RTE_GSO_SEG_SIZE_MIN)
Can you please explain why it is correct that the min len for VXLAN_TNL or
GRE_TNL is that of TCP MIN size (RTE_GSO_SEG_SIZE_MIN)
>
To make the macros above and their usage below clearer:
1. I would change the || with &&. and == with !=
#define ILLEGAL_UDP_GSO_CTX(ctx) \
((((ctx)->gso_types & DEV_TX_OFFLOAD_UDP_TSO) != 0) && \
(ctx)->gso_size < RTE_GSO_UDP_SEG_SIZE_MIN)
#define ILLEGAL_TCP_GSO_CTX(ctx) \
((((ctx)->gso_types & (DEV_TX_OFFLOAD_TCP_TSO | \
DEV_TX_OFFLOAD_VXLAN_TNL_TSO | \
DEV_TX_OFFLOAD_GRE_TNL_TSO)) != 0) && \
(ctx)->gso_size < RTE_GSO_SEG_SIZE_MIN)
2. Then later I would change the && with ||
Changing original:
(ILLEGAL_UDP_GSO_CTX(gso_ctx) &&
ILLEGAL_TCP_GSO_CTX(gso_ctx)))
With this:
ILLEGAL_UDP_GSO_CTX(gso_ctx) ||
ILLEGAL_TCP_GSO_CTX(gso_ctx))
> int
> rte_gso_segment(struct rte_mbuf *pkt,
> @@ -27,14 +38,12 @@ rte_gso_segment(struct rte_mbuf *pkt,
>
> if (pkt == NULL || pkts_out == NULL || gso_ctx == NULL ||
> nb_pkts_out < 1 ||
> - gso_ctx->gso_size < RTE_GSO_SEG_SIZE_MIN ||
> - ((gso_ctx->gso_types &
> (DEV_TX_OFFLOAD_TCP_TSO |
> - DEV_TX_OFFLOAD_VXLAN_TNL_TSO |
> - DEV_TX_OFFLOAD_GRE_TNL_TSO)) == 0))
> + (ILLEGAL_UDP_GSO_CTX(gso_ctx) &&
> + ILLEGAL_TCP_GSO_CTX(gso_ctx)))
> return -EINVAL;
>
> if (gso_ctx->gso_size >= pkt->pkt_len) {
> - pkt->ol_flags &= (~PKT_TX_TCP_SEG);
> + pkt->ol_flags &= (~(PKT_TX_TCP_SEG | PKT_TX_UDP_SEG));
> pkts_out[0] = pkt;
> return 1;
> }
> @@ -59,6 +68,11 @@ rte_gso_segment(struct rte_mbuf *pkt,
> ret = gso_tcp4_segment(pkt, gso_size, ipid_delta,
> direct_pool, indirect_pool,
> pkts_out, nb_pkts_out);
> + } else if (IS_IPV4_UDP(pkt->ol_flags) &&
> + (gso_ctx->gso_types &
> DEV_TX_OFFLOAD_UDP_TSO)) {
> + pkt->ol_flags &= (~PKT_TX_UDP_SEG);
> + ret = gso_udp4_segment(pkt, gso_size, direct_pool,
> + indirect_pool, pkts_out, nb_pkts_out);
> } else {
> /* unsupported packet, skip */
> pkts_out[0] = pkt;
> diff --git a/lib/librte_gso/rte_gso.h b/lib/librte_gso/rte_gso.h index
> f4abd61..a626a11 100644
> --- a/lib/librte_gso/rte_gso.h
> +++ b/lib/librte_gso/rte_gso.h
> @@ -17,10 +17,14 @@ extern "C" {
> #include <stdint.h>
> #include <rte_mbuf.h>
>
> -/* Minimum GSO segment size. */
> +/* Minimum GSO segment size for TCP based packets. */
> #define RTE_GSO_SEG_SIZE_MIN (sizeof(struct ether_hdr) + \
> sizeof(struct ipv4_hdr) + sizeof(struct tcp_hdr) + 1)
RTE_GSO_SEG_SIZE_MIN is actually TCP min size. Can you name this macro as
RTE_GSO_TCP_SEG_SIZE_MIN (symmetrically to the UDP macro below)?
>
> +/* Minimum GSO segment size for UDP based packets. */ #define
> +RTE_GSO_UDP_SEG_SIZE_MIN (sizeof(struct ether_hdr) + \
> + sizeof(struct ipv4_hdr) + sizeof(struct udp_hdr) + 1)
> +
> /* GSO flags for rte_gso_ctx. */
> #define RTE_GSO_FLAG_IPID_FIXED (1ULL << 0) /**< Use fixed IP ids for
> output GSO segments. Setting
> --
> 2.7.4
