gso: add VXLAN UDP GSO support

From: Yi Yang <yangyi01@inspur.com>

Many NICs can't offload VXLAN UFO, so it is very important
to do VXLAN UDP GSO by software to improve VM-to-VM UDP
performance, especially for the case that VM MTU is just
1500 but not 9000.

With this enabled in DPDK, OVS DPDK can leverage it to
improve VM-to-VM UDP performance, performance gain is very
huge, over 2 times.

Signed-off-by: Yi Yang <yangyi01@inspur.com>
---
 lib/librte_gso/Makefile          |   1 +
 lib/librte_gso/gso_common.h      |   5 ++
 lib/librte_gso/gso_tunnel_udp4.c | 108 +++++++++++++++++++++++++++++++++++++++
 lib/librte_gso/gso_tunnel_udp4.h |  43 ++++++++++++++++
 lib/librte_gso/meson.build       |   2 +-
 lib/librte_gso/rte_gso.c         |   8 +++
 6 files changed, 166 insertions(+), 1 deletion(-)
 create mode 100644 lib/librte_gso/gso_tunnel_udp4.c
 create mode 100644 lib/librte_gso/gso_tunnel_udp4.h
  

Jiayu, also please help  review this GSO patch, thanks a lot.


















At 2020-07-01 14:46:43, yang_y_yi@163.com wrote:
>From: Yi Yang <yangyi01@inspur.com>
>
>Many NICs can't offload VXLAN UFO, so it is very important
>to do VXLAN UDP GSO by software to improve VM-to-VM UDP
>performance, especially for the case that VM MTU is just
>1500 but not 9000.
>
>With this enabled in DPDK, OVS DPDK can leverage it to
>improve VM-to-VM UDP performance, performance gain is very
>huge, over 2 times.
>
>Signed-off-by: Yi Yang <yangyi01@inspur.com>
>---
> lib/librte_gso/Makefile          |   1 +
> lib/librte_gso/gso_common.h      |   5 ++
> lib/librte_gso/gso_tunnel_udp4.c | 108 +++++++++++++++++++++++++++++++++++++++
> lib/librte_gso/gso_tunnel_udp4.h |  43 ++++++++++++++++
> lib/librte_gso/meson.build       |   2 +-
> lib/librte_gso/rte_gso.c         |   8 +++
> 6 files changed, 166 insertions(+), 1 deletion(-)
> create mode 100644 lib/librte_gso/gso_tunnel_udp4.c
> create mode 100644 lib/librte_gso/gso_tunnel_udp4.h
>
>diff --git a/lib/librte_gso/Makefile b/lib/librte_gso/Makefile
>index a34846e..3005817 100644
>--- a/lib/librte_gso/Makefile
>+++ b/lib/librte_gso/Makefile
>@@ -17,6 +17,7 @@ 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-$(CONFIG_RTE_LIBRTE_GSO) += gso_tunnel_udp4.c
> SRCS-$(CONFIG_RTE_LIBRTE_GSO) += gso_udp4.c
> 
> # install this header file
>diff --git a/lib/librte_gso/gso_common.h b/lib/librte_gso/gso_common.h
>index a0b8343..4d5f303 100644
>--- a/lib/librte_gso/gso_common.h
>+++ b/lib/librte_gso/gso_common.h
>@@ -26,6 +26,11 @@
> 		(PKT_TX_TCP_SEG | PKT_TX_IPV4 | PKT_TX_OUTER_IPV4 | \
> 		 PKT_TX_TUNNEL_VXLAN))
> 
>+#define IS_IPV4_VXLAN_UDP4(flag) (((flag) & (PKT_TX_UDP_SEG | PKT_TX_IPV4 | \
>+				PKT_TX_OUTER_IPV4 | PKT_TX_TUNNEL_MASK)) == \
>+		(PKT_TX_UDP_SEG | PKT_TX_IPV4 | PKT_TX_OUTER_IPV4 | \
>+		 PKT_TX_TUNNEL_VXLAN))
>+
> #define IS_IPV4_GRE_TCP4(flag) (((flag) & (PKT_TX_TCP_SEG | PKT_TX_IPV4 | \
> 				PKT_TX_OUTER_IPV4 | PKT_TX_TUNNEL_MASK)) == \
> 		(PKT_TX_TCP_SEG | PKT_TX_IPV4 | PKT_TX_OUTER_IPV4 | \
>diff --git a/lib/librte_gso/gso_tunnel_udp4.c b/lib/librte_gso/gso_tunnel_udp4.c
>new file mode 100644
>index 0000000..1a018ee
>--- /dev/null
>+++ b/lib/librte_gso/gso_tunnel_udp4.c
>@@ -0,0 +1,108 @@
>+/* SPDX-License-Identifier: BSD-3-Clause
>+ * Copyright(c) 2020 Inspur Corporation
>+ */
>+
>+#include "gso_common.h"
>+#include "gso_tunnel_udp4.h"
>+
>+#define IPV4_HDR_MF_BIT (1U << 13)
>+
>+static void
>+update_tunnel_ipv4_udp_headers(struct rte_mbuf *pkt, struct rte_mbuf **segs,
>+			       uint16_t nb_segs)
>+{
>+	struct rte_ipv4_hdr *ipv4_hdr;
>+	uint16_t outer_id, inner_id, tail_idx, i, length;
>+	uint16_t outer_ipv4_offset, inner_ipv4_offset;
>+	uint16_t udp_gre_offset, udp_offset;
>+	uint8_t update_udp_hdr;
>+	uint16_t frag_offset = 0, is_mf;
>+
>+	outer_ipv4_offset = pkt->outer_l2_len;
>+	udp_gre_offset = outer_ipv4_offset + pkt->outer_l3_len;
>+	inner_ipv4_offset = udp_gre_offset + pkt->l2_len;
>+	udp_offset = inner_ipv4_offset + pkt->l3_len;
>+
>+	/* Outer IPv4 header. */
>+	ipv4_hdr = (struct rte_ipv4_hdr *)(rte_pktmbuf_mtod(pkt, char *) +
>+			outer_ipv4_offset);
>+	outer_id = rte_be_to_cpu_16(ipv4_hdr->packet_id);
>+
>+	/* Inner IPv4 header. */
>+	ipv4_hdr = (struct rte_ipv4_hdr *)(rte_pktmbuf_mtod(pkt, char *) +
>+			inner_ipv4_offset);
>+	inner_id = rte_be_to_cpu_16(ipv4_hdr->packet_id);
>+
>+	tail_idx = nb_segs - 1;
>+
>+	/* Only update UDP header for VxLAN packets. */
>+	update_udp_hdr = (pkt->ol_flags & PKT_TX_TUNNEL_VXLAN) ? 1 : 0;
>+
>+	for (i = 0; i < nb_segs; i++) {
>+		update_ipv4_header(segs[i], outer_ipv4_offset, outer_id);
>+		if (update_udp_hdr)
>+			update_udp_header(segs[i], udp_gre_offset);
>+		update_ipv4_header(segs[i], inner_ipv4_offset, inner_id);
>+		update_udp_header(segs[i], udp_offset);
>+		/* For the case inner packet is UDP, we must keep UDP
>+		 * datagram boundary, it must be handled as IP fragment.
>+		 *
>+		 * Set IP fragment offset for inner IP header.
>+		 */
>+		ipv4_hdr = (struct rte_ipv4_hdr *)
>+			(rte_pktmbuf_mtod(segs[i], char *) +
>+				inner_ipv4_offset);
>+		is_mf = i < tail_idx ? IPV4_HDR_MF_BIT : 0;
>+		ipv4_hdr->fragment_offset =
>+			rte_cpu_to_be_16(frag_offset | is_mf);
>+		length = segs[i]->pkt_len - inner_ipv4_offset - pkt->l3_len;
>+		frag_offset += (length >> 3);
>+		outer_id++;
>+	}
>+}
>+
>+int
>+gso_tunnel_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 rte_ipv4_hdr *inner_ipv4_hdr;
>+	uint16_t pyld_unit_size, hdr_offset, frag_off;
>+	int ret = 1;
>+
>+	hdr_offset = pkt->outer_l2_len + pkt->outer_l3_len + pkt->l2_len;
>+	inner_ipv4_hdr = (struct rte_ipv4_hdr *)(rte_pktmbuf_mtod(pkt, char *) +
>+			hdr_offset);
>+	/*
>+	 * Don't process the packet whose MF bit or offset in the inner
>+	 * IPv4 header are non-zero.
>+	 */
>+	frag_off = rte_be_to_cpu_16(inner_ipv4_hdr->fragment_offset);
>+	if (unlikely(IS_FRAGMENTED(frag_off))) {
>+		pkts_out[0] = pkt;
>+		return 1;
>+	}
>+
>+	hdr_offset += pkt->l3_len;
>+	/* Don't process the packet without data */
>+	if ((hdr_offset + pkt->l4_len) >= pkt->pkt_len) {
>+		pkts_out[0] = pkt;
>+		return 1;
>+	}
>+
>+	/* pyld_unit_size must be a multiple of 8 because frag_off
>+	 * uses 8 bytes as unit.
>+	 */
>+	pyld_unit_size = (gso_size - hdr_offset) & ~7U;
>+
>+	/* 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_tunnel_ipv4_udp_headers(pkt, pkts_out, ret);
>+
>+	return ret;
>+}
>diff --git a/lib/librte_gso/gso_tunnel_udp4.h b/lib/librte_gso/gso_tunnel_udp4.h
>new file mode 100644
>index 0000000..d56e342
>--- /dev/null
>+++ b/lib/librte_gso/gso_tunnel_udp4.h
>@@ -0,0 +1,43 @@
>+/* SPDX-License-Identifier: BSD-3-Clause
>+ * Copyright(c) 2020 Inspur Corporation
>+ */
>+
>+#ifndef _GSO_TUNNEL_UDP4_H_
>+#define _GSO_TUNNEL_UDP4_H_
>+
>+#include <stdint.h>
>+#include <rte_mbuf.h>
>+
>+/**
>+ * Segment a tunneling packet with inner TCP/IPv4 headers. This function
>+ * does not check if the input packet has correct checksums, and does not
>+ * update checksums for output GSO segments. Furthermore, it does not
>+ * 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 it 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_tunnel_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 ad8dd85..05904f2 100644
>--- a/lib/librte_gso/meson.build
>+++ b/lib/librte_gso/meson.build
>@@ -2,6 +2,6 @@
> # Copyright(c) 2017 Intel Corporation
> 
> sources = files('gso_common.c', 'gso_tcp4.c', 'gso_udp4.c',
>- 		'gso_tunnel_tcp4.c', 'rte_gso.c')
>+		'gso_tunnel_tcp4.c', 'gso_tunnel_udp4.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 751b5b6..cf401b2 100644
>--- a/lib/librte_gso/rte_gso.c
>+++ b/lib/librte_gso/rte_gso.c
>@@ -11,6 +11,7 @@
> #include "gso_common.h"
> #include "gso_tcp4.h"
> #include "gso_tunnel_tcp4.h"
>+#include "gso_tunnel_udp4.h"
> #include "gso_udp4.h"
> 
> #define ILLEGAL_UDP_GSO_CTX(ctx) \
>@@ -62,6 +63,13 @@
> 		ret = gso_tunnel_tcp4_segment(pkt, gso_size, ipid_delta,
> 				direct_pool, indirect_pool,
> 				pkts_out, nb_pkts_out);
>+	} else if (IS_IPV4_VXLAN_UDP4(pkt->ol_flags) &&
>+			(gso_ctx->gso_types & (DEV_TX_OFFLOAD_VXLAN_TNL_TSO |
>+					       DEV_TX_OFFLOAD_UDP_TSO))) {
>+		pkt->ol_flags &= (~PKT_TX_UDP_SEG);
>+		ret = gso_tunnel_udp4_segment(pkt, gso_size,
>+				direct_pool, indirect_pool,
>+				pkts_out, nb_pkts_out);
> 	} else if (IS_IPV4_TCP(pkt->ol_flags) &&
> 			(gso_ctx->gso_types & DEV_TX_OFFLOAD_TCP_TSO)) {
> 		pkt->ol_flags &= (~PKT_TX_TCP_SEG);
>-- 
>1.8.3.1