usbip: vudc: Add vudc_rx

Add functions which allows to receive urbs from the client.
It receives traffic in a loop in a separate thread.

This commit is a result of cooperation between Samsung R&D Institute
Poland and Open Operating Systems Student Society at University
of Warsaw (O2S3@UW) consisting of:

    Igor Kotrasinski <ikotrasinsk@gmail.com>
    Karol Kosik <karo9@interia.eu>
    Ewelina Kosmider <3w3lfin@gmail.com>
    Dawid Lazarczyk <lazarczyk.dawid@gmail.com>
    Piotr Szulc <ps347277@students.mimuw.edu.pl>

Tutor and project owner:
    Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Igor Kotrasinski <i.kotrasinsk@samsung.com>
Signed-off-by: Karol Kosik <karo9@interia.eu>
Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/usbip/vudc_rx.c

+/*
+ * Copyright (C) 2015 Karol Kosik <karo9@interia.eu>
+ * Copyright (C) 2015-2016 Samsung Electronics
+ *               Igor Kotrasinski <i.kotrasinsk@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <net/sock.h>
+#include <linux/list.h>
+#include <linux/kthread.h>
+
+#include "usbip_common.h"
+#include "vudc.h"
+
+static int alloc_urb_from_cmd(struct urb **urbp,
+			      struct usbip_header *pdu, u8 type)
+{
+	struct urb *urb;
+
+	if (type == USB_ENDPOINT_XFER_ISOC)
+		urb = usb_alloc_urb(pdu->u.cmd_submit.number_of_packets,
+					  GFP_KERNEL);
+	else
+		urb = usb_alloc_urb(0, GFP_KERNEL);
+
+	if (!urb)
+		goto err;
+
+	usbip_pack_pdu(pdu, urb, USBIP_CMD_SUBMIT, 0);
+
+	if (urb->transfer_buffer_length > 0) {
+		urb->transfer_buffer = kzalloc(urb->transfer_buffer_length,
+			GFP_KERNEL);
+		if (!urb->transfer_buffer)
+			goto free_urb;
+	}
+
+	urb->setup_packet = kmemdup(&pdu->u.cmd_submit.setup, 8,
+			    GFP_KERNEL);
+	if (!urb->setup_packet)
+		goto free_buffer;
+
+	/*
+	 * FIXME - we only setup pipe enough for usbip functions
+	 * to behave nicely
+	 */
+	urb->pipe |= pdu->base.direction == USBIP_DIR_IN ?
+			USB_DIR_IN : USB_DIR_OUT;
+
+	*urbp = urb;
+	return 0;
+
+free_buffer:
+	kfree(urb->transfer_buffer);
+	urb->transfer_buffer = NULL;
+free_urb:
+	usb_free_urb(urb);
+err:
+	return -ENOMEM;
+}
+
+static int v_recv_cmd_unlink(struct vudc *udc,
+				struct usbip_header *pdu)
+{
+	unsigned long flags;
+	struct urbp *urb_p;
+
+	spin_lock_irqsave(&udc->lock, flags);
+	list_for_each_entry(urb_p, &udc->urb_queue, urb_entry) {
+		if (urb_p->seqnum != pdu->u.cmd_unlink.seqnum)
+			continue;
+		urb_p->urb->unlinked = -ECONNRESET;
+		urb_p->seqnum = pdu->base.seqnum;
+		v_kick_timer(udc, jiffies);
+		spin_unlock_irqrestore(&udc->lock, flags);
+		return 0;
+	}
+	/* Not found, completed / not queued */
+	spin_lock(&udc->lock_tx);
+	v_enqueue_ret_unlink(udc, pdu->base.seqnum, 0);
+	wake_up(&udc->tx_waitq);
+	spin_unlock(&udc->lock_tx);
+	spin_unlock_irqrestore(&udc->lock, flags);
+
+	return 0;
+}
+
+static int v_recv_cmd_submit(struct vudc *udc,
+				 struct usbip_header *pdu)
+{
+	int ret = 0;
+	struct urbp *urb_p;
+	u8 address;
+	unsigned long flags;
+
+	urb_p = alloc_urbp();
+	if (!urb_p) {
+		usbip_event_add(&udc->ud, VUDC_EVENT_ERROR_MALLOC);
+		return -ENOMEM;
+	}
+
+	/* base.ep is pipeendpoint(pipe) */
+	address = pdu->base.ep;
+	if (pdu->base.direction == USBIP_DIR_IN)
+		address |= USB_DIR_IN;
+
+	spin_lock_irq(&udc->lock);
+	urb_p->ep = find_endpoint(udc, address);
+	if (!urb_p->ep) {
+		/* we don't know the type, there may be isoc data! */
+		dev_err(&udc->pdev->dev, "request to nonexistent endpoint");
+		spin_unlock_irq(&udc->lock);
+		usbip_event_add(&udc->ud, VUDC_EVENT_ERROR_TCP);
+		ret = -EPIPE;
+		goto free_urbp;
+	}
+	urb_p->type = urb_p->ep->type;
+	spin_unlock_irq(&udc->lock);
+
+	urb_p->new = 1;
+	urb_p->seqnum = pdu->base.seqnum;
+
+	ret = alloc_urb_from_cmd(&urb_p->urb, pdu, urb_p->ep->type);
+	if (ret) {
+		usbip_event_add(&udc->ud, VUDC_EVENT_ERROR_MALLOC);
+		ret = -ENOMEM;
+		goto free_urbp;
+	}
+
+	urb_p->urb->status = -EINPROGRESS;
+
+	/* FIXME: more pipe setup to please usbip_common */
+	urb_p->urb->pipe &= ~(11 << 30);
+	switch (urb_p->ep->type) {
+	case USB_ENDPOINT_XFER_BULK:
+		urb_p->urb->pipe |= (PIPE_BULK << 30);
+		break;
+	case USB_ENDPOINT_XFER_INT:
+		urb_p->urb->pipe |= (PIPE_INTERRUPT << 30);
+		break;
+	case USB_ENDPOINT_XFER_CONTROL:
+		urb_p->urb->pipe |= (PIPE_CONTROL << 30);
+		break;
+	case USB_ENDPOINT_XFER_ISOC:
+		urb_p->urb->pipe |= (PIPE_ISOCHRONOUS << 30);
+		break;
+	}
+	ret = usbip_recv_xbuff(&udc->ud, urb_p->urb);
+	if (ret < 0)
+		goto free_urbp;
+
+	ret = usbip_recv_iso(&udc->ud, urb_p->urb);
+	if (ret < 0)
+		goto free_urbp;
+
+	spin_lock_irqsave(&udc->lock, flags);
+	v_kick_timer(udc, jiffies);
+	list_add_tail(&urb_p->urb_entry, &udc->urb_queue);
+	spin_unlock_irqrestore(&udc->lock, flags);
+
+	return 0;
+
+free_urbp:
+	free_urbp_and_urb(urb_p);
+	return ret;
+}
+
+static int v_rx_pdu(struct usbip_device *ud)
+{
+	int ret;
+	struct usbip_header pdu;
+	struct vudc *udc = container_of(ud, struct vudc, ud);
+
+	memset(&pdu, 0, sizeof(pdu));
+	ret = usbip_recv(ud->tcp_socket, &pdu, sizeof(pdu));
+	if (ret != sizeof(pdu)) {
+		usbip_event_add(ud, VUDC_EVENT_ERROR_TCP);
+		if (ret >= 0)
+			return -EPIPE;
+		return ret;
+	}
+	usbip_header_correct_endian(&pdu, 0);
+
+	spin_lock_irq(&ud->lock);
+	ret = (ud->status == SDEV_ST_USED);
+	spin_unlock_irq(&ud->lock);
+	if (!ret) {
+		usbip_event_add(ud, VUDC_EVENT_ERROR_TCP);
+		return -EBUSY;
+	}
+
+	switch (pdu.base.command) {
+	case USBIP_CMD_UNLINK:
+		ret = v_recv_cmd_unlink(udc, &pdu);
+		break;
+	case USBIP_CMD_SUBMIT:
+		ret = v_recv_cmd_submit(udc, &pdu);
+		break;
+	default:
+		ret = -EPIPE;
+		pr_err("rx: unknown command");
+		break;
+	}
+	return ret;
+}
+
+int v_rx_loop(void *data)
+{
+	struct usbip_device *ud = data;
+	int ret = 0;
+
+	while (!kthread_should_stop()) {
+		if (usbip_event_happened(ud))
+			break;
+		ret = v_rx_pdu(ud);
+		if (ret < 0) {
+			pr_warn("v_rx exit with error %d", ret);
+			break;
+		}
+	}
+	return ret;
+}