[dpdk-dev] [PATCH] vhost: support UDP Fragmentation Offload

[Jiayu Hu]

In virtio, UDP Fragmentation Offload (UFO) includes two parts: host UFO
and guest UFO. Guest UFO means the frontend can receive large UDP packets,
and host UFO means the backend can receive large UDP packets. This patch
supports host UFO and guest UFO for vhost-user.

Signed-off-by: Jiayu Hu <jiayu.hu at intel.com>
---
 lib/librte_mbuf/rte_mbuf.h    |  7 +++++++
 lib/librte_vhost/vhost.h      |  2 ++
 lib/librte_vhost/virtio_net.c | 10 ++++++++++
 3 files changed, 19 insertions(+)

diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index ce8a05d..3d8cfc9 100644
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -209,6 +209,13 @@ extern "C" {
 /* add new TX flags here */
 
 /**
+ * UDP Fragmentation Offload flag. This flag is used for enabling UDP
+ * fragmentation in SW or in HW. When use UFO, mbuf->tso_segsz is used
+ * to store the MSS of UDP fragments.
+ */
+#define PKT_TX_UDP_SEG	(1ULL << 42)
+
+/**
  * Request security offload processing on the TX packet.
  */
 #define PKT_TX_SEC_OFFLOAD 		(1ULL << 43)
diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index 1cc81c1..fc109ef 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -206,10 +206,12 @@ struct vhost_msg {
 				(1ULL << VHOST_USER_F_PROTOCOL_FEATURES) | \
 				(1ULL << VIRTIO_NET_F_HOST_TSO4) | \
 				(1ULL << VIRTIO_NET_F_HOST_TSO6) | \
+				(1ULL << VIRTIO_NET_F_HOST_UFO) | \
 				(1ULL << VIRTIO_NET_F_CSUM)    | \
 				(1ULL << VIRTIO_NET_F_GUEST_CSUM) | \
 				(1ULL << VIRTIO_NET_F_GUEST_TSO4) | \
 				(1ULL << VIRTIO_NET_F_GUEST_TSO6) | \
+				(1ULL << VIRTIO_NET_F_GUEST_UFO) | \
 				(1ULL << VIRTIO_RING_F_INDIRECT_DESC) | \
 				(1ULL << VIRTIO_NET_F_MTU) | \
 				(1ULL << VIRTIO_F_IOMMU_PLATFORM))
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 6fee16e..3a3a0ad 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -188,6 +188,11 @@ virtio_enqueue_offload(struct rte_mbuf *m_buf, struct virtio_net_hdr *net_hdr)
 		net_hdr->gso_size = m_buf->tso_segsz;
 		net_hdr->hdr_len = m_buf->l2_len + m_buf->l3_len
 					+ m_buf->l4_len;
+	} else if (m_buf->ol_flags & PKT_TX_UDP_SEG) {
+		net_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
+		net_hdr->gso_size = m_buf->tso_segsz;
+		net_hdr->hdr_len = m_buf->l2_len + m_buf->l3_len +
+			m_buf->l4_len;
 	} else {
 		ASSIGN_UNLESS_EQUAL(net_hdr->gso_type, 0);
 		ASSIGN_UNLESS_EQUAL(net_hdr->gso_size, 0);
@@ -834,6 +839,11 @@ vhost_dequeue_offload(struct virtio_net_hdr *hdr, struct rte_mbuf *m)
 			m->tso_segsz = hdr->gso_size;
 			m->l4_len = (tcp_hdr->data_off & 0xf0) >> 2;
 			break;
+		case VIRTIO_NET_HDR_GSO_UDP:
+			m->ol_flags |= PKT_TX_UDP_SEG;
+			m->tso_segsz = hdr->gso_size;
+			m->l4_len = sizeof(struct udp_hdr);
+			break;
 		default:
 			RTE_LOG(WARNING, VHOST_DATA,
 				"unsupported gso type %u.\n", hdr->gso_type);
-- 
2.7.4