xen/pvcalls: implement connect command

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.

[ boris: fixed whitespaces ]

Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
CC: boris.ostrovsky@oracle.com
CC: jgross@suse.com
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

1 files changed, 179 insertions, 0 deletions

diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c
index 8f436e51053a..c0fc774221ca 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 +115,150 @@ 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;
+        struct sockaddr *sa = (struct sockaddr *)&req->u.connect.addr;
+
+        fedata = dev_get_drvdata(&dev->dev);
+
+        if (req->u.connect.len < sizeof(sa->sa_family) ||
+            req->u.connect.len > sizeof(req->u.connect.addr) ||
+            sa->sa_family != AF_INET)
+                goto out;
+
+        ret = sock_create(AF_INET, SOCK_STREAM, 0, &sock);
+        if (ret < 0)
+                goto out;
+        ret = inet_stream_connect(sock, sa, req->u.connect.len, 0);
+        if (ret < 0) {
+                sock_release(sock);
+                goto out;
+        }
+
+        map = pvcalls_new_active_socket(fedata,
+                                        req->u.connect.id,
+                                        req->u.connect.ref,
+                                        req->u.connect.evtchn,
+                                        sock);
+        if (!map) {
+                ret = -EFAULT;
+                sock_release(map->sock);
+        }
+
+out:
+        rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
+        rsp->req_id = req->req_id;
+        rsp->cmd = req->cmd;
+        rsp->u.connect.id = req->u.connect.id;
+        rsp->ret = ret;
+
+        return 0;
+}
+
+static int pvcalls_back_release_active(struct xenbus_device *dev,
+                                       struct pvcalls_fedata *fedata,
+                                       struct sock_mapping *map)
+{
         return 0;
 }
 
@@ -206,6 +380,11 @@ static irqreturn_t pvcalls_back_event(int irq, void *dev_id)
         return IRQ_HANDLED;
 }
 
+static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map)
+{
+        return IRQ_HANDLED;
+}
+
 static int backend_connect(struct xenbus_device *dev)
 {
         int err, evtchn;