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

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

On 25.03.2021 13:18, Stefano Garzarella wrote:
> 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?
Ack, i'll fix it
>
> 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) {
>> -- 
>> 2.25.1
>>
>