Re: [RFC PATCH v7 14/22] virtio/vsock: rest of SOCK_SEQPACKET support

Stefano Garzarella
2021-03-25T10:18:55Z

On Tue, Mar 23, 2021 at 04:13:29PM +0300, Arseny Krasnov wrote:
>This adds rest of logic for SEQPACKET:
>1) SEQPACKET specific functions which send SEQ_BEGIN/SEQ_END.
> Note that both functions may sleep to wait enough space for
> SEQPACKET header.
>2) SEQ_BEGIN/SEQ_END in TAP packet capture.
>3) Send SHUTDOWN on socket close for SEQPACKET type.
>4) Set SEQPACKET packet type during send.
>5) Set MSG_EOR in flags for SEQPACKET during send.
>6) 'seqpacket_allow' flag to virtio transport.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
> v6 -> v7:
> In 'virtio_transport_seqpacket_enqueue()', 'next_tx_msg_id' is updated
> in both cases when message send successfully or error occured.
>
> include/linux/virtio_vsock.h | 7 ++
> net/vmw_vsock/virtio_transport_common.c | 88 ++++++++++++++++++++++++-
> 2 files changed, 93 insertions(+), 2 deletions(-)
>
>diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
>index 0e3aa395c07c..ab5f56fd7251 100644
>--- a/include/linux/virtio_vsock.h
>+++ b/include/linux/virtio_vsock.h
>@@ -22,6 +22,7 @@ struct virtio_vsock_seq_state {
> u32 user_read_seq_len;
> u32 user_read_copied;
> u32 curr_rx_msg_id;
>+ u32 next_tx_msg_id;
> };
>
> /* Per-socket state (accessed via vsk->trans) */
>@@ -76,6 +77,8 @@ struct virtio_transport {
>
> /* Takes ownership of the packet */
> int (*send_pkt)(struct virtio_vsock_pkt *pkt);
>+
>+ bool seqpacket_allow;
> };
>
> ssize_t
>@@ -89,6 +92,10 @@ virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
> size_t len, int flags);
>
> int
>+virtio_transport_seqpacket_enqueue(struct vsock_sock *vsk,
>+ struct msghdr *msg,
>+ size_t len);
>+int
> virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
> struct msghdr *msg,
> int flags,
>diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>index bfe0d7026bf8..01a56c7da8bd 100644
>--- a/net/vmw_vsock/virtio_transport_common.c
>+++ b/net/vmw_vsock/virtio_transport_common.c
>@@ -139,6 +139,8 @@ 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:
>+ case VIRTIO_VSOCK_OP_SEQ_END:
> hdr->op = cpu_to_le16(AF_VSOCK_OP_CONTROL);
> break;
> default:
>@@ -187,7 +189,12 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
> struct virtio_vsock_pkt *pkt;
> u32 pkt_len = info->pkt_len;
>
>- info->type = VIRTIO_VSOCK_TYPE_STREAM;
>+ info->type = virtio_transport_get_type(sk_vsock(vsk));
>+
>+ if (info->type == VIRTIO_VSOCK_TYPE_SEQPACKET &&
>+ info->msg &&
>+ info->msg->msg_flags & MSG_EOR)
>+ info->flags |= VIRTIO_VSOCK_RW_EOR;
>
> t_ops = virtio_transport_get_ops(vsk);
> if (unlikely(!t_ops))
>@@ -401,6 +408,43 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
> return err;
> }
>
>+static int virtio_transport_seqpacket_send_ctrl(struct vsock_sock *vsk,
>+ int type,
>+ size_t len,
>+ int flags)
>+{
>+ struct virtio_vsock_sock *vvs = vsk->trans;
>+ struct virtio_vsock_pkt_info info = {
>+ .op = type,
>+ .vsk = vsk,
>+ .pkt_len = sizeof(struct virtio_vsock_seq_hdr)
>+ };
>+
>+ struct virtio_vsock_seq_hdr seq_hdr = {
>+ .msg_id = cpu_to_le32(vvs->seq_state.next_tx_msg_id),
>+ .msg_len = cpu_to_le32(len)
>+ };
>+
>+ struct kvec seq_hdr_kiov = {
>+ .iov_base = (void *)&seq_hdr,
>+ .iov_len = sizeof(struct virtio_vsock_seq_hdr)
>+ };
>+
>+ struct msghdr msg = {0};
>+
>+ //XXX: do we need 'vsock_transport_send_notify_data' pointer?
>+ if (vsock_wait_space(sk_vsock(vsk),
>+ sizeof(struct virtio_vsock_seq_hdr),
>+ flags, NULL))
>+ return -1;
>+
>+ iov_iter_kvec(&msg.msg_iter, WRITE, &seq_hdr_kiov, 1, sizeof(seq_hdr));
>+
>+ info.msg = &msg;
>+
>+ return virtio_transport_send_pkt_info(vsk, &info);
>+}
>+
> static inline void virtio_transport_remove_pkt(struct virtio_vsock_pkt *pkt)
> {
> list_del(&pkt->list);
>@@ -595,6 +639,46 @@ virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
> }
> EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_dequeue);
>
>+int
>+virtio_transport_seqpacket_enqueue(struct vsock_sock *vsk,
>+ struct msghdr *msg,
>+ size_t len)
>+{
>+ int written = -1;
>+
>+ if (msg->msg_iter.iov_offset == 0) {
>+ /* Send SEQBEGIN. */
>+ if (virtio_transport_seqpacket_send_ctrl(vsk,
>+ VIRTIO_VSOCK_OP_SEQ_BEGIN,
>+ len,
>+ msg->msg_flags) < 0)
>+ goto out;
>+ }
>+
>+ written = virtio_transport_stream_enqueue(vsk, msg, len);
>+
>+ if (written < 0)
>+ goto out;
>+
>+ if (msg->msg_iter.count == 0) {
>+ /* Send SEQEND. */
>+ virtio_transport_seqpacket_send_ctrl(vsk,
>+ VIRTIO_VSOCK_OP_SEQ_END,
>+ 0,
>+ msg->msg_flags);

What happen if this fail?

In the previous version we returned -1, now we return the bytes
transmitted, is that right?

The rest LGTM.

>+ }
>+out:
>+ /* Update next id on error or message transmission done. */
>+ if (written < 0 || msg->msg_iter.count == 0) {
>+ struct virtio_vsock_sock *vvs = vsk->trans;
>+
>+ vvs->seq_state.next_tx_msg_id++;
>+ }
>+
>+ return written;
>+}
>+EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_enqueue);
>+
> int
> virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
> struct msghdr *msg,
>@@ -1014,7 +1098,7 @@ void virtio_transport_release(struct vsock_sock *vsk)
> struct sock *sk = &vsk->sk;
> bool remove_sock = true;
>
>- if (sk->sk_type == SOCK_STREAM)
>+ if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)
> remove_sock = virtio_transport_close(vsk);
>
> list_for_each_entry_safe(pkt, tmp, &vvs->rx_queue, list) {