Re: [RFC PATCH v3 10/13] virtio/vsock: rest of SOCK_SEQPACKET support

[Stefano Garzarella <sgarzare@redhat.com>]

On Mon, Jan 25, 2021 at 02:15:26PM +0300, Arseny Krasnov wrote:
>This adds rest of logic for SEQPACKET:
>1) Shared functions for packet sending now set valid type of packet
>   according socket type.
>2) SEQPACKET specific function like SEQ_BEGIN send and data dequeue.
>3) TAP support for SEQPACKET is not so easy if it is necessary to
>send whole record to TAP interface. This could be done by allocating
>new packet when whole record is received, data of record must be
>copied to TAP packet.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> include/linux/virtio_vsock.h            |  7 ++++
> net/vmw_vsock/virtio_transport_common.c | 55 +++++++++++++++++++++----
> 2 files changed, 55 insertions(+), 7 deletions(-)
>
>diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
>index af8705ea8b95..ad9783df97c9 100644
>--- a/include/linux/virtio_vsock.h
>+++ b/include/linux/virtio_vsock.h
>@@ -84,7 +84,14 @@ virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
> 			       struct msghdr *msg,
> 			       size_t len, int flags);
>
>+bool virtio_transport_seqpacket_seq_send_len(struct vsock_sock *vsk, size_t len);
> size_t virtio_transport_seqpacket_seq_get_len(struct vsock_sock *vsk);
>+ssize_t
>+virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
>+				   struct msghdr *msg,
>+				   size_t len,
>+				   int type);
>+
> s64 virtio_transport_stream_has_data(struct vsock_sock *vsk);
> s64 virtio_transport_stream_has_space(struct vsock_sock *vsk);
>
>diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>index 90f9feef9d8f..fab14679ca7b 100644
>--- a/net/vmw_vsock/virtio_transport_common.c
>+++ b/net/vmw_vsock/virtio_transport_common.c
>@@ -139,6 +139,7 @@ static struct sk_buff *virtio_transport_build_skb(void *opaque)
> 		break;
> 	case VIRTIO_VSOCK_OP_CREDIT_UPDATE:
> 	case VIRTIO_VSOCK_OP_CREDIT_REQUEST:
>+	case VIRTIO_VSOCK_OP_SEQ_BEGIN:
> 		hdr->op = cpu_to_le16(AF_VSOCK_OP_CONTROL);
> 		break;
> 	default:
>@@ -157,6 +158,10 @@ static struct sk_buff *virtio_transport_build_skb(void *opaque)
>
> void virtio_transport_deliver_tap_pkt(struct virtio_vsock_pkt *pkt)
> {
>+	/* TODO: implement tap support for SOCK_SEQPACKET. */

I think we should do this before merging SOCK_SEQPACKET support because 
it can be very useful to use tcpdump to figure out what's going on, do 
you think it's complicated?

>+	if (le16_to_cpu(pkt->hdr.type) == VIRTIO_VSOCK_TYPE_SEQPACKET)
>+		return;
>+
> 	if (pkt->tap_delivered)
> 		return;
>
>@@ -405,6 +410,19 @@ static u16 virtio_transport_get_type(struct sock *sk)
> 		return VIRTIO_VSOCK_TYPE_SEQPACKET;
> }
>
>+bool virtio_transport_seqpacket_seq_send_len(struct vsock_sock *vsk, size_t len)
>+{
>+	struct virtio_vsock_pkt_info info = {
>+		.type = VIRTIO_VSOCK_TYPE_SEQPACKET,
>+		.op = VIRTIO_VSOCK_OP_SEQ_BEGIN,
>+		.vsk = vsk,
>+		.flags = len
>+	};
>+
>+	return virtio_transport_send_pkt_info(vsk, &info);
>+}
>+EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_seq_send_len);
>+
> static inline void virtio_transport_del_n_free_pkt(struct virtio_vsock_pkt *pkt)
> {
> 	list_del(&pkt->list);
>@@ -576,6 +594,18 @@ virtio_transport_stream_dequeue(struct vsock_sock *vsk,
> }
> EXPORT_SYMBOL_GPL(virtio_transport_stream_dequeue);
>
>+ssize_t
>+virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
>+				   struct msghdr *msg,
>+				   size_t len, int flags)
>+{
>+	if (flags & MSG_PEEK)
>+		return -EOPNOTSUPP;
>+
>+	return virtio_transport_seqpacket_do_dequeue(vsk, msg, len);
>+}
>+EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_dequeue);
>+
> int
> virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
> 			       struct msghdr *msg,
>@@ -659,14 +689,15 @@ EXPORT_SYMBOL_GPL(virtio_transport_do_socket_init);
> void virtio_transport_notify_buffer_size(struct vsock_sock *vsk, u64 *val)
> {
> 	struct virtio_vsock_sock *vvs = vsk->trans;
>+	int type;
>
> 	if (*val > VIRTIO_VSOCK_MAX_BUF_SIZE)
> 		*val = VIRTIO_VSOCK_MAX_BUF_SIZE;
>
> 	vvs->buf_alloc = *val;
>
>-	virtio_transport_send_credit_update(vsk, VIRTIO_VSOCK_TYPE_STREAM,
>-					    NULL);
>+	type = virtio_transport_get_type(sk_vsock(vsk));

How about setting the type in virtio_transport_send_pkt_info(), so we 
can avoid all these changes?


>+	virtio_transport_send_credit_update(vsk, type, NULL);
> }
> EXPORT_SYMBOL_GPL(virtio_transport_notify_buffer_size);
>
>@@ -793,10 +824,11 @@ int virtio_transport_connect(struct vsock_sock *vsk)
> {
> 	struct virtio_vsock_pkt_info info = {
> 		.op = VIRTIO_VSOCK_OP_REQUEST,
>-		.type = VIRTIO_VSOCK_TYPE_STREAM,
> 		.vsk = vsk,
> 	};
>
>+	info.type = virtio_transport_get_type(sk_vsock(vsk));
>+
> 	return virtio_transport_send_pkt_info(vsk, &info);
> }
> EXPORT_SYMBOL_GPL(virtio_transport_connect);
>@@ -805,7 +837,6 @@ int virtio_transport_shutdown(struct vsock_sock *vsk, int mode)
> {
> 	struct virtio_vsock_pkt_info info = {
> 		.op = VIRTIO_VSOCK_OP_SHUTDOWN,
>-		.type = VIRTIO_VSOCK_TYPE_STREAM,
> 		.flags = (mode & RCV_SHUTDOWN ?
> 			  VIRTIO_VSOCK_SHUTDOWN_RCV : 0) |
> 			 (mode & SEND_SHUTDOWN ?
>@@ -813,6 +844,8 @@ int virtio_transport_shutdown(struct vsock_sock *vsk, int mode)
> 		.vsk = vsk,
> 	};
>
>+	info.type = virtio_transport_get_type(sk_vsock(vsk));
>+
> 	return virtio_transport_send_pkt_info(vsk, &info);
> }
> EXPORT_SYMBOL_GPL(virtio_transport_shutdown);
>@@ -834,12 +867,18 @@ virtio_transport_stream_enqueue(struct vsock_sock *vsk,
> {
> 	struct virtio_vsock_pkt_info info = {
> 		.op = VIRTIO_VSOCK_OP_RW,
>-		.type = VIRTIO_VSOCK_TYPE_STREAM,
> 		.msg = msg,
> 		.pkt_len = len,
> 		.vsk = vsk,
>+		.flags = 0,
> 	};
>
>+	info.type = virtio_transport_get_type(sk_vsock(vsk));
>+
>+	if (info.type == VIRTIO_VSOCK_TYPE_SEQPACKET &&
>+	    msg->msg_flags & MSG_EOR)
>+		info.flags |= VIRTIO_VSOCK_RW_EOR;
>+
> 	return virtio_transport_send_pkt_info(vsk, &info);
> }
> EXPORT_SYMBOL_GPL(virtio_transport_stream_enqueue);
>@@ -857,7 +896,6 @@ static int virtio_transport_reset(struct vsock_sock *vsk,
> {
> 	struct virtio_vsock_pkt_info info = {
> 		.op = VIRTIO_VSOCK_OP_RST,
>-		.type = VIRTIO_VSOCK_TYPE_STREAM,
> 		.reply = !!pkt,
> 		.vsk = vsk,
> 	};
>@@ -866,6 +904,8 @@ static int virtio_transport_reset(struct vsock_sock *vsk,
> 	if (pkt && le16_to_cpu(pkt->hdr.op) == VIRTIO_VSOCK_OP_RST)
> 		return 0;
>
>+	info.type = virtio_transport_get_type(sk_vsock(vsk));
>+
> 	return virtio_transport_send_pkt_info(vsk, &info);
> }
>
>@@ -1177,13 +1217,14 @@ virtio_transport_send_response(struct vsock_sock *vsk,
> {
> 	struct virtio_vsock_pkt_info info = {
> 		.op = VIRTIO_VSOCK_OP_RESPONSE,
>-		.type = VIRTIO_VSOCK_TYPE_STREAM,
> 		.remote_cid = le64_to_cpu(pkt->hdr.src_cid),
> 		.remote_port = le32_to_cpu(pkt->hdr.src_port),
> 		.reply = true,
> 		.vsk = vsk,
> 	};
>
>+	info.type = virtio_transport_get_type(sk_vsock(vsk));
>+
> 	return virtio_transport_send_pkt_info(vsk, &info);
> }
>
>-- 
>2.25.1
>

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