[PATCH-v5 0/4] vsock: cancel connect packets when failing to connect

[PATCH-v5 0/4] vsock: cancel connect packets when failing to connect

[Peng Tao]

Currently, if a connect call fails on a signal or timeout (e.g., guest is still
in the process of starting up), we'll just return to caller and leave the connect
packet queued and they are sent even though the connection is considered a failure,
which can confuse applications with unwanted false connect attempt.

The patchset enables vsock (both host and guest) to cancel queued packets when
a connect attempt is considered to fail.

v5 changelog:
  - change virtio_vsock_pkt->cancel_token back to virtio_vsock_pkt->vsk
v4 changelog:
  - drop two unnecessary void * cast
  - update new callback comment
v3 changelog:
  - define cancel_pkt callback in struct vsock_transport rather than struct virtio_transport
  - rename virtio_vsock_pkt->vsk to virtio_vsock_pkt->cancel_token
v2 changelog:
  - fix queued_replies counting and resume tx/rx when necessary

Cheers,
Tao

Peng Tao (4):
  vsock: track pkt owner vsock
  vhost-vsock: add pkt cancel capability
  vsock: add pkt cancel capability
  vsock: cancel packets when failing to connect

 drivers/vhost/vsock.c                   | 41 ++++++++++++++++++++++++++++++++
 include/linux/virtio_vsock.h            |  3 +++
 include/net/af_vsock.h                  |  3 +++
 net/vmw_vsock/af_vsock.c                | 14 +++++++++++
 net/vmw_vsock/virtio_transport.c        | 42 +++++++++++++++++++++++++++++++++
 net/vmw_vsock/virtio_transport_common.c |  7 ++++++
 6 files changed, 110 insertions(+)

-- 
2.7.4

[PATCH-v5 1/4] vsock: track pkt owner vsock

[Peng Tao]

So that we can cancel a queued pkt later if necessary.

Signed-off-by: Peng Tao <bergwolf@gmail.com>
---
 include/linux/virtio_vsock.h            | 3 +++
 net/vmw_vsock/virtio_transport_common.c | 7 +++++++
 2 files changed, 10 insertions(+)

diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
index 9638bfe..584f9a6 100644
--- a/include/linux/virtio_vsock.h
+++ b/include/linux/virtio_vsock.h
@@ -48,6 +48,8 @@ struct virtio_vsock_pkt {
 	struct virtio_vsock_hdr	hdr;
 	struct work_struct work;
 	struct list_head list;
+	/* socket refcnt not held, only use for cancellation */
+	struct vsock_sock *vsk;
 	void *buf;
 	u32 len;
 	u32 off;
@@ -56,6 +58,7 @@ struct virtio_vsock_pkt {
 
 struct virtio_vsock_pkt_info {
 	u32 remote_cid, remote_port;
+	struct vsock_sock *vsk;
 	struct msghdr *msg;
 	u32 pkt_len;
 	u16 type;
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 8d592a4..af087b4 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -58,6 +58,7 @@ virtio_transport_alloc_pkt(struct virtio_vsock_pkt_info *info,
 	pkt->len		= len;
 	pkt->hdr.len		= cpu_to_le32(len);
 	pkt->reply		= info->reply;
+	pkt->vsk		= info->vsk;
 
 	if (info->msg && len > 0) {
 		pkt->buf = kmalloc(len, GFP_KERNEL);
@@ -180,6 +181,7 @@ static int virtio_transport_send_credit_update(struct vsock_sock *vsk,
 	struct virtio_vsock_pkt_info info = {
 		.op = VIRTIO_VSOCK_OP_CREDIT_UPDATE,
 		.type = type,
+		.vsk = vsk,
 	};
 
 	return virtio_transport_send_pkt_info(vsk, &info);
@@ -519,6 +521,7 @@ 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,
 	};
 
 	return virtio_transport_send_pkt_info(vsk, &info);
@@ -534,6 +537,7 @@ int virtio_transport_shutdown(struct vsock_sock *vsk, int mode)
 			  VIRTIO_VSOCK_SHUTDOWN_RCV : 0) |
 			 (mode & SEND_SHUTDOWN ?
 			  VIRTIO_VSOCK_SHUTDOWN_SEND : 0),
+		.vsk = vsk,
 	};
 
 	return virtio_transport_send_pkt_info(vsk, &info);
@@ -560,6 +564,7 @@ virtio_transport_stream_enqueue(struct vsock_sock *vsk,
 		.type = VIRTIO_VSOCK_TYPE_STREAM,
 		.msg = msg,
 		.pkt_len = len,
+		.vsk = vsk,
 	};
 
 	return virtio_transport_send_pkt_info(vsk, &info);
@@ -581,6 +586,7 @@ static int virtio_transport_reset(struct vsock_sock *vsk,
 		.op = VIRTIO_VSOCK_OP_RST,
 		.type = VIRTIO_VSOCK_TYPE_STREAM,
 		.reply = !!pkt,
+		.vsk = vsk,
 	};
 
 	/* Send RST only if the original pkt is not a RST pkt */
@@ -826,6 +832,7 @@ virtio_transport_send_response(struct vsock_sock *vsk,
 		.remote_cid = le64_to_cpu(pkt->hdr.src_cid),
 		.remote_port = le32_to_cpu(pkt->hdr.src_port),
 		.reply = true,
+		.vsk = vsk,
 	};
 
 	return virtio_transport_send_pkt_info(vsk, &info);
-- 
2.7.4

[PATCH-v5 2/4] vhost-vsock: add pkt cancel capability

[Peng Tao]

To allow canceling all packets of a connection.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Jorgen Hansen <jhansen@vmware.com>
Signed-off-by: Peng Tao <bergwolf@gmail.com>
---
 drivers/vhost/vsock.c  | 41 +++++++++++++++++++++++++++++++++++++++++
 include/net/af_vsock.h |  3 +++
 2 files changed, 44 insertions(+)

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index ce5e63d..57babce 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -223,6 +223,46 @@ vhost_transport_send_pkt(struct virtio_vsock_pkt *pkt)
 	return len;
 }
 
+static int
+vhost_transport_cancel_pkt(struct vsock_sock *vsk)
+{
+	struct vhost_vsock *vsock;
+	struct virtio_vsock_pkt *pkt, *n;
+	int cnt = 0;
+	LIST_HEAD(freeme);
+
+	/* Find the vhost_vsock according to guest context id  */
+	vsock = vhost_vsock_get(vsk->remote_addr.svm_cid);
+	if (!vsock)
+		return -ENODEV;
+
+	spin_lock_bh(&vsock->send_pkt_list_lock);
+	list_for_each_entry_safe(pkt, n, &vsock->send_pkt_list, list) {
+		if (pkt->vsk != vsk)
+			continue;
+		list_move(&pkt->list, &freeme);
+	}
+	spin_unlock_bh(&vsock->send_pkt_list_lock);
+
+	list_for_each_entry_safe(pkt, n, &freeme, list) {
+		if (pkt->reply)
+			cnt++;
+		list_del(&pkt->list);
+		virtio_transport_free_pkt(pkt);
+	}
+
+	if (cnt) {
+		struct vhost_virtqueue *tx_vq = &vsock->vqs[VSOCK_VQ_TX];
+		int new_cnt;
+
+		new_cnt = atomic_sub_return(cnt, &vsock->queued_replies);
+		if (new_cnt + cnt >= tx_vq->num && new_cnt < tx_vq->num)
+			vhost_poll_queue(&tx_vq->poll);
+	}
+
+	return 0;
+}
+
 static struct virtio_vsock_pkt *
 vhost_vsock_alloc_pkt(struct vhost_virtqueue *vq,
 		      unsigned int out, unsigned int in)
@@ -675,6 +715,7 @@ static struct virtio_transport vhost_transport = {
 		.release                  = virtio_transport_release,
 		.connect                  = virtio_transport_connect,
 		.shutdown                 = virtio_transport_shutdown,
+		.cancel_pkt               = vhost_transport_cancel_pkt,
 
 		.dgram_enqueue            = virtio_transport_dgram_enqueue,
 		.dgram_dequeue            = virtio_transport_dgram_dequeue,
diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index f275896..f32ed9a 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -100,6 +100,9 @@ struct vsock_transport {
 	void (*destruct)(struct vsock_sock *);
 	void (*release)(struct vsock_sock *);
 
+	/* Cancel all pending packets sent on vsock. */
+	int (*cancel_pkt)(struct vsock_sock *vsk);
+
 	/* Connections. */
 	int (*connect)(struct vsock_sock *);
 
-- 
2.7.4

[PATCH-v5 3/4] vsock: add pkt cancel capability

[Peng Tao]

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Peng Tao <bergwolf@gmail.com>
---
 net/vmw_vsock/virtio_transport.c | 42 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 9d24c0e..bcab8f2 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -213,6 +213,47 @@ virtio_transport_send_pkt(struct virtio_vsock_pkt *pkt)
 	return len;
 }
 
+static int
+virtio_transport_cancel_pkt(struct vsock_sock *vsk)
+{
+	struct virtio_vsock *vsock;
+	struct virtio_vsock_pkt *pkt, *n;
+	int cnt = 0;
+	LIST_HEAD(freeme);
+
+	vsock = virtio_vsock_get();
+	if (!vsock) {
+		return -ENODEV;
+	}
+
+	spin_lock_bh(&vsock->send_pkt_list_lock);
+	list_for_each_entry_safe(pkt, n, &vsock->send_pkt_list, list) {
+		if (pkt->vsk != vsk)
+			continue;
+		list_move(&pkt->list, &freeme);
+	}
+	spin_unlock_bh(&vsock->send_pkt_list_lock);
+
+	list_for_each_entry_safe(pkt, n, &freeme, list) {
+		if (pkt->reply)
+			cnt++;
+		list_del(&pkt->list);
+		virtio_transport_free_pkt(pkt);
+	}
+
+	if (cnt) {
+		struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
+		int new_cnt;
+
+		new_cnt = atomic_sub_return(cnt, &vsock->queued_replies);
+		if (new_cnt + cnt >= virtqueue_get_vring_size(rx_vq) &&
+		    new_cnt < virtqueue_get_vring_size(rx_vq))
+			queue_work(virtio_vsock_workqueue, &vsock->rx_work);
+	}
+
+	return 0;
+}
+
 static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
 {
 	int buf_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
@@ -462,6 +503,7 @@ static struct virtio_transport virtio_transport = {
 		.release                  = virtio_transport_release,
 		.connect                  = virtio_transport_connect,
 		.shutdown                 = virtio_transport_shutdown,
+		.cancel_pkt               = virtio_transport_cancel_pkt,
 
 		.dgram_bind               = virtio_transport_dgram_bind,
 		.dgram_dequeue            = virtio_transport_dgram_dequeue,
-- 
2.7.4

[PATCH-v5 4/4] vsock: cancel packets when failing to connect

[Peng Tao]

Otherwise we'll leave the packets queued until releasing vsock device.
E.g., if guest is slow to start up, resulting ETIMEDOUT on connect, guest
will get the connect requests from failed host sockets.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Jorgen Hansen <jhansen@vmware.com>
Signed-off-by: Peng Tao <bergwolf@gmail.com>
---
 net/vmw_vsock/af_vsock.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 9192ead..756542a 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -1102,10 +1102,19 @@ static const struct proto_ops vsock_dgram_ops = {
 	.sendpage = sock_no_sendpage,
 };
 
+static int vsock_transport_cancel_pkt(struct vsock_sock *vsk)
+{
+	if (!transport->cancel_pkt)
+		return -EOPNOTSUPP;
+
+	return transport->cancel_pkt(vsk);
+}
+
 static void vsock_connect_timeout(struct work_struct *work)
 {
 	struct sock *sk;
 	struct vsock_sock *vsk;
+	int cancel = 0;
 
 	vsk = container_of(work, struct vsock_sock, dwork.work);
 	sk = sk_vsock(vsk);
@@ -1116,8 +1125,11 @@ static void vsock_connect_timeout(struct work_struct *work)
 		sk->sk_state = SS_UNCONNECTED;
 		sk->sk_err = ETIMEDOUT;
 		sk->sk_error_report(sk);
+		cancel = 1;
 	}
 	release_sock(sk);
+	if (cancel)
+		vsock_transport_cancel_pkt(vsk);
 
 	sock_put(sk);
 }
@@ -1224,11 +1236,13 @@ static int vsock_stream_connect(struct socket *sock, struct sockaddr *addr,
 			err = sock_intr_errno(timeout);
 			sk->sk_state = SS_UNCONNECTED;
 			sock->state = SS_UNCONNECTED;
+			vsock_transport_cancel_pkt(vsk);
 			goto out_wait;
 		} else if (timeout == 0) {
 			err = -ETIMEDOUT;
 			sk->sk_state = SS_UNCONNECTED;
 			sock->state = SS_UNCONNECTED;
+			vsock_transport_cancel_pkt(vsk);
 			goto out_wait;
 		}
 
-- 
2.7.4

Re: [PATCH-v5 0/4] vsock: cancel connect packets when failing to connect

[Stefan Hajnoczi]

[-- Attachment #1.1: Type: text/plain, Size: 921 bytes --]

On Wed, Mar 15, 2017 at 09:32:13AM +0800, Peng Tao wrote:
> Currently, if a connect call fails on a signal or timeout (e.g., guest is still
> in the process of starting up), we'll just return to caller and leave the connect
> packet queued and they are sent even though the connection is considered a failure,
> which can confuse applications with unwanted false connect attempt.
> 
> The patchset enables vsock (both host and guest) to cancel queued packets when
> a connect attempt is considered to fail.
> 
> v5 changelog:
>   - change virtio_vsock_pkt->cancel_token back to virtio_vsock_pkt->vsk

As discussed previously, it's an opaque token that is not interpreted or
dereferenced.  A unique integer could be used instead of the pointer we
conveniently use as the token today.  I still think it should be void *
or uintptr_t, but let's move on.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

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Re: [PATCH-v5 0/4] vsock: cancel connect packets when failing to connect

[David Miller]

From: Peng Tao <bergwolf@gmail.com>
Date: Wed, 15 Mar 2017 09:32:13 +0800

> Currently, if a connect call fails on a signal or timeout (e.g., guest is still
> in the process of starting up), we'll just return to caller and leave the connect
> packet queued and they are sent even though the connection is considered a failure,
> which can confuse applications with unwanted false connect attempt.
> 
> The patchset enables vsock (both host and guest) to cancel queued packets when
> a connect attempt is considered to fail.
> 
> v5 changelog:
>   - change virtio_vsock_pkt->cancel_token back to virtio_vsock_pkt->vsk
> v4 changelog:
>   - drop two unnecessary void * cast
>   - update new callback comment
> v3 changelog:
>   - define cancel_pkt callback in struct vsock_transport rather than struct virtio_transport
>   - rename virtio_vsock_pkt->vsk to virtio_vsock_pkt->cancel_token
> v2 changelog:
>   - fix queued_replies counting and resume tx/rx when necessary

Series applied, thanks.