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

[Arseny Krasnov]

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@xxxxxxxxxxxxx>
---
 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. */
+	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));
+	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