[PATCH v10 12/18] virtio/vsock: add SEQPACKET receive logic

[Arseny Krasnov <arseny.krasnov@kaspersky.com>]

Update current receive logic for SEQPACKET support: performs
check for packet and socket types on receive(if mismatch, then
reset connection).

Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
---
 v9 -> v10:
 1) Commit message updated.
 2) Comment updated.
 3) Updated way to to set 'last_pkt' flags.

 net/vmw_vsock/virtio_transport_common.c | 30 ++++++++++++++++++++++---
 1 file changed, 27 insertions(+), 3 deletions(-)

diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 61349b2ea7fe..a6f8b0f39775 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -165,6 +165,14 @@ void virtio_transport_deliver_tap_pkt(struct virtio_vsock_pkt *pkt)
 }
 EXPORT_SYMBOL_GPL(virtio_transport_deliver_tap_pkt);
 
+static u16 virtio_transport_get_type(struct sock *sk)
+{
+	if (sk->sk_type == SOCK_STREAM)
+		return VIRTIO_VSOCK_TYPE_STREAM;
+	else
+		return VIRTIO_VSOCK_TYPE_SEQPACKET;
+}
+
 /* This function can only be used on connecting/connected sockets,
  * since a socket assigned to a transport is required.
  *
@@ -979,13 +987,17 @@ virtio_transport_recv_enqueue(struct vsock_sock *vsk,
 					   struct virtio_vsock_pkt, list);
 
 		/* If there is space in the last packet queued, we copy the
-		 * new packet in its buffer.
+		 * new packet in its buffer(except SEQPACKET case, when we
+		 * also check that last packet is not last packet of previous
+		 * record).
 		 */
-		if (pkt->len <= last_pkt->buf_len - last_pkt->len) {
+		if ((pkt->len <= last_pkt->buf_len - last_pkt->len) &&
+		    !(le32_to_cpu(last_pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOR)) {
 			memcpy(last_pkt->buf + last_pkt->len, pkt->buf,
 			       pkt->len);
 			last_pkt->len += pkt->len;
 			free_pkt = true;
+			last_pkt->hdr.flags |= pkt->hdr.flags;
 			goto out;
 		}
 	}
@@ -1151,6 +1163,12 @@ virtio_transport_recv_listen(struct sock *sk, struct virtio_vsock_pkt *pkt,
 	return 0;
 }
 
+static bool virtio_transport_valid_type(u16 type)
+{
+	return (type == VIRTIO_VSOCK_TYPE_STREAM) ||
+	       (type == VIRTIO_VSOCK_TYPE_SEQPACKET);
+}
+
 /* We are under the virtio-vsock's vsock->rx_lock or vhost-vsock's vq->mutex
  * lock.
  */
@@ -1176,7 +1194,7 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
 					le32_to_cpu(pkt->hdr.buf_alloc),
 					le32_to_cpu(pkt->hdr.fwd_cnt));
 
-	if (le16_to_cpu(pkt->hdr.type) != VIRTIO_VSOCK_TYPE_STREAM) {
+	if (!virtio_transport_valid_type(le16_to_cpu(pkt->hdr.type))) {
 		(void)virtio_transport_reset_no_sock(t, pkt);
 		goto free_pkt;
 	}
@@ -1193,6 +1211,12 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
 		}
 	}
 
+	if (virtio_transport_get_type(sk) != le16_to_cpu(pkt->hdr.type)) {
+		(void)virtio_transport_reset_no_sock(t, pkt);
+		sock_put(sk);
+		goto free_pkt;
+	}
+
 	vsk = vsock_sk(sk);
 
 	lock_sock(sk);
-- 
2.25.1