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SubjectRe: [PATCH v6 08/18] xen/pvcalls: implement connect command
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On 03/07/17 23:08, Stefano Stabellini wrote:
> Allocate a socket. Keep track of socket <-> ring mappings with a new data
> structure, called sock_mapping. Implement the connect command by calling
> inet_stream_connect, and mapping the new indexes page and data ring.
> Allocate a workqueue and a work_struct, called ioworker, to perform
> reads and writes to the socket.
>
> When an active socket is closed (sk_state_change), set in_error to
> -ENOTCONN and notify the other end, as specified by the protocol.
>
> sk_data_ready and pvcalls_back_ioworker will be implemented later.
>
> Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
> CC: boris.ostrovsky@oracle.com
> CC: jgross@suse.com
> ---
> drivers/xen/pvcalls-back.c | 174 +++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 174 insertions(+)
>
> diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c
> index 53fd908..1bc2620 100644
> --- a/drivers/xen/pvcalls-back.c
> +++ b/drivers/xen/pvcalls-back.c
> @@ -54,6 +54,39 @@ struct pvcalls_fedata {
> struct semaphore socket_lock;
> };
>
> +struct pvcalls_ioworker {
> + struct work_struct register_work;
> + struct workqueue_struct *wq;
> +};
> +
> +struct sock_mapping {
> + struct list_head list;
> + struct pvcalls_fedata *fedata;
> + struct socket *sock;
> + uint64_t id;
> + grant_ref_t ref;
> + struct pvcalls_data_intf *ring;
> + void *bytes;
> + struct pvcalls_data data;
> + uint32_t ring_order;
> + int irq;
> + atomic_t read;
> + atomic_t write;
> + atomic_t io;
> + atomic_t release;
> + void (*saved_data_ready)(struct sock *sk);
> + struct pvcalls_ioworker ioworker;
> +};
> +
> +static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map);
> +static int pvcalls_back_release_active(struct xenbus_device *dev,
> + struct pvcalls_fedata *fedata,
> + struct sock_mapping *map);
> +
> +static void pvcalls_back_ioworker(struct work_struct *work)
> +{
> +}
> +
> static int pvcalls_back_socket(struct xenbus_device *dev,
> struct xen_pvcalls_request *req)
> {
> @@ -82,9 +115,145 @@ static int pvcalls_back_socket(struct xenbus_device *dev,
> return 0;
> }
>
> +static void pvcalls_sk_state_change(struct sock *sock)
> +{
> + struct sock_mapping *map = sock->sk_user_data;
> + struct pvcalls_data_intf *intf;
> +
> + if (map == NULL)
> + return;
> +
> + intf = map->ring;
> + intf->in_error = -ENOTCONN;
> + notify_remote_via_irq(map->irq);
> +}
> +
> +static void pvcalls_sk_data_ready(struct sock *sock)
> +{
> +}
> +
> +static struct sock_mapping *pvcalls_new_active_socket(
> + struct pvcalls_fedata *fedata,
> + uint64_t id,
> + grant_ref_t ref,
> + uint32_t evtchn,
> + struct socket *sock)
> +{
> + int ret;
> + struct sock_mapping *map;
> + void *page;
> +
> + map = kzalloc(sizeof(*map), GFP_KERNEL);
> + if (map == NULL)
> + return NULL;
> +
> + map->fedata = fedata;
> + map->sock = sock;
> + map->id = id;
> + map->ref = ref;
> +
> + ret = xenbus_map_ring_valloc(fedata->dev, &ref, 1, &page);
> + if (ret < 0)
> + goto out;
> + map->ring = page;
> + map->ring_order = map->ring->ring_order;
> + /* first read the order, then map the data ring */
> + virt_rmb();
> + if (map->ring_order > MAX_RING_ORDER) {
> + pr_warn("%s frontend requested ring_order %u, which is > MAX (%u)\n",
> + __func__, map->ring_order, MAX_RING_ORDER);
> + goto out;
> + }
> + ret = xenbus_map_ring_valloc(fedata->dev, map->ring->ref,
> + (1 << map->ring_order), &page);
> + if (ret < 0)
> + goto out;
> + map->bytes = page;
> +
> + ret = bind_interdomain_evtchn_to_irqhandler(fedata->dev->otherend_id,
> + evtchn,
> + pvcalls_back_conn_event,
> + 0,
> + "pvcalls-backend",
> + map);
> + if (ret < 0)
> + goto out;
> + map->irq = ret;
> +
> + map->data.in = map->bytes;
> + map->data.out = map->bytes + XEN_FLEX_RING_SIZE(map->ring_order);
> +
> + map->ioworker.wq = alloc_workqueue("pvcalls_io", WQ_UNBOUND, 1);
> + if (!map->ioworker.wq)
> + goto out;
> + atomic_set(&map->io, 1);
> + INIT_WORK(&map->ioworker.register_work, pvcalls_back_ioworker);
> +
> + down(&fedata->socket_lock);
> + list_add_tail(&map->list, &fedata->socket_mappings);
> + up(&fedata->socket_lock);
> +
> + write_lock_bh(&map->sock->sk->sk_callback_lock);
> + map->saved_data_ready = map->sock->sk->sk_data_ready;
> + map->sock->sk->sk_user_data = map;
> + map->sock->sk->sk_data_ready = pvcalls_sk_data_ready;
> + map->sock->sk->sk_state_change = pvcalls_sk_state_change;
> + write_unlock_bh(&map->sock->sk->sk_callback_lock);
> +
> + return map;
> +out:
> + down(&fedata->socket_lock);
> + list_del(&map->list);
> + pvcalls_back_release_active(fedata->dev, fedata, map);
> + up(&fedata->socket_lock);
> + return NULL;
> +}
> +
> static int pvcalls_back_connect(struct xenbus_device *dev,
> struct xen_pvcalls_request *req)
> {
> + struct pvcalls_fedata *fedata;
> + int ret = -EINVAL;
> + struct socket *sock;
> + struct sock_mapping *map;
> + struct xen_pvcalls_response *rsp;
> +
> + fedata = dev_get_drvdata(&dev->dev);
> +
> + ret = sock_create(AF_INET, SOCK_STREAM, 0, &sock);
> + if (ret < 0)
> + goto out;
> + ret = inet_stream_connect(sock, (struct sockaddr *)&req->u.connect.addr,
> + req->u.connect.len, req->u.connect.flags);

Shouldn't there be some kind of validation, e.g. whether
req->u.connect.len isn't larger than sizeof(req->u.connect.addr) ?

Are all flags really valid to specify? I'd like to have at least a
comment stating that everything is save without validation.


Juergen

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