Re: [RFC PATCH v6 13/22] virtio/vsock: add SEQPACKET receive logic

Stefano Garzarella
2021-03-15T11:16:08Z

On Sun, Mar 07, 2021 at 09:02:50PM +0300, Arseny Krasnov wrote:
>This modifies current receive logic for SEQPACKET support:
>1) Inserts 'SEQ_BEGIN' packet to socket's rx queue.
>2) Inserts 'RW' packet to socket's rx queue, but without merging with
> buffer of last packet in queue.
>3) Performs check for packet and socket types on receive(if mismatch,
> then reset connection).
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> net/vmw_vsock/virtio_transport_common.c | 63 +++++++++++++++++--------
> 1 file changed, 44 insertions(+), 19 deletions(-)
>
>diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>index 6fc78fec41c0..9d86375935ce 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.
> *
>@@ -1062,25 +1070,27 @@ virtio_transport_recv_enqueue(struct vsock_sock *vsk,
> goto out;
> }
>
>- /* Try to copy small packets into the buffer of last packet queued,
>- * to avoid wasting memory queueing the entire buffer with a small
>- * payload.
>- */
>- if (pkt->len <= GOOD_COPY_LEN && !list_empty(&vvs->rx_queue)) {
>- struct virtio_vsock_pkt *last_pkt;
>+ if (le16_to_cpu(pkt->hdr.type) == VIRTIO_VSOCK_TYPE_STREAM) {
>+ /* Try to copy small packets into the buffer of last packet queued,
>+ * to avoid wasting memory queueing the entire buffer with a small
>+ * payload.
>+ */
>+ if (pkt->len <= GOOD_COPY_LEN && !list_empty(&vvs->rx_queue)) {
>+ struct virtio_vsock_pkt *last_pkt;
>
>- last_pkt = list_last_entry(&vvs->rx_queue,
>- struct virtio_vsock_pkt, list);
>+ last_pkt = list_last_entry(&vvs->rx_queue,
>+ struct virtio_vsock_pkt, list);
>
>- /* If there is space in the last packet queued, we copy the
>- * new packet in its buffer.
>- */
>- if (pkt->len <= last_pkt->buf_len - last_pkt->len) {
>- memcpy(last_pkt->buf + last_pkt->len, pkt->buf,
>- pkt->len);
>- last_pkt->len += pkt->len;
>- free_pkt = true;
>- goto out;
>+ /* If there is space in the last packet queued, we copy the
>+ * new packet in its buffer.
>+ */
>+ if (pkt->len <= last_pkt->buf_len - last_pkt->len) {
>+ memcpy(last_pkt->buf + last_pkt->len, pkt->buf,
>+ pkt->len);
>+ last_pkt->len += pkt->len;
>+ free_pkt = true;
>+ goto out;
>+ }
> }
> }
>
>@@ -1100,9 +1110,13 @@ virtio_transport_recv_connected(struct sock *sk,
> int err = 0;
>
> switch (le16_to_cpu(pkt->hdr.op)) {
>+ case VIRTIO_VSOCK_OP_SEQ_BEGIN:
>+ case VIRTIO_VSOCK_OP_SEQ_END:
> case VIRTIO_VSOCK_OP_RW:
> virtio_transport_recv_enqueue(vsk, pkt);
>- sk->sk_data_ready(sk);
>+
>+ if (le16_to_cpu(pkt->hdr.op) != VIRTIO_VSOCK_OP_SEQ_BEGIN)
>+ sk->sk_data_ready(sk);
> return err;
> case VIRTIO_VSOCK_OP_CREDIT_UPDATE:
> sk->sk_write_space(sk);
>@@ -1245,6 +1259,12 @@ 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.
> */
>@@ -1270,7 +1290,7 @@ 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;
> }
>@@ -1287,6 +1307,11 @@ 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);

We must release the refcnt acquired by vsock_find_connected_socket() or
vsock_find_bound_socket(), so we need to add:

sock_put(sk);

>+ goto free_pkt;
>+ }
>+
> vsk = vsock_sk(sk);
>
> lock_sock(sk);
>--
>2.25.1