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

Arseny Krasnov
2021-03-23T13:15:01Z

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);
+ }
+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) {
--
2.25.1