1/*
  2 * Copyright (C) 2003-2008 Takahiro Hirofuchi
  3 *
  4 * This is free software; you can redistribute it and/or modify
  5 * it under the terms of the GNU General Public License as published by
  6 * the Free Software Foundation; either version 2 of the License, or
  7 * (at your option) any later version.
  8 *
  9 * This is distributed in the hope that it will be useful,
 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 12 * GNU General Public License for more details.
 13 *
 14 * You should have received a copy of the GNU General Public License
 15 * along with this program; if not, write to the Free Software
 16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
 17 * USA.
 18 */
 19
 20#include <linux/kthread.h>
 21#include <linux/slab.h>
 22
 23#include "usbip_common.h"
 24#include "vhci.h"
 25
 26/* get URB from transmitted urb queue. caller must hold vdev->priv_lock */
 27struct urb *pickup_urb_and_free_priv(struct vhci_device *vdev, __u32 seqnum)
 28{
 29	struct vhci_priv *priv, *tmp;
 30	struct urb *urb = NULL;
 31	int status;
 32
 33	list_for_each_entry_safe(priv, tmp, &vdev->priv_rx, list) {
 34		if (priv->seqnum != seqnum)
 35			continue;
 36
 37		urb = priv->urb;
 38		status = urb->status;
 39
 40		usbip_dbg_vhci_rx("find urb %p vurb %p seqnum %u\n",
 41				urb, priv, seqnum);
 42
 43		switch (status) {
 44		case -ENOENT:
 45			/* fall through */
 46		case -ECONNRESET:
 47			dev_info(&urb->dev->dev,
 48				 "urb %p was unlinked %ssynchronuously.\n", urb,
 49				 status == -ENOENT ? "" : "a");
 50			break;
 51		case -EINPROGRESS:
 52			/* no info output */
 53			break;
 54		default:
 55			dev_info(&urb->dev->dev,
 56				 "urb %p may be in a error, status %d\n", urb,
 57				 status);
 58		}
 59
 60		list_del(&priv->list);
 61		kfree(priv);
 62		urb->hcpriv = NULL;
 63
 64		break;
 65	}
 66
 67	return urb;
 68}
 69
 70static void vhci_recv_ret_submit(struct vhci_device *vdev,
 71				 struct usbip_header *pdu)
 72{
 73	struct vhci_hcd *vhci = vdev_to_vhci(vdev);
 74	struct usbip_device *ud = &vdev->ud;
 75	struct urb *urb;
 76	unsigned long flags;
 77
 78	spin_lock_irqsave(&vdev->priv_lock, flags);
 79	urb = pickup_urb_and_free_priv(vdev, pdu->base.seqnum);
 80	spin_unlock_irqrestore(&vdev->priv_lock, flags);
 81
 82	if (!urb) {
 83		pr_err("cannot find a urb of seqnum %u\n", pdu->base.seqnum);
 84		pr_info("max seqnum %d\n",
 85			atomic_read(&vhci->seqnum));
 86		usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
 87		return;
 88	}
 89
 90	/* unpack the pdu to a urb */
 91	usbip_pack_pdu(pdu, urb, USBIP_RET_SUBMIT, 0);
 92
 93	/* recv transfer buffer */
 94	if (usbip_recv_xbuff(ud, urb) < 0)
 95		return;
 96
 97	/* recv iso_packet_descriptor */
 98	if (usbip_recv_iso(ud, urb) < 0)
 99		return;
100
101	/* restore the padding in iso packets */
102	usbip_pad_iso(ud, urb);
103
104	if (usbip_dbg_flag_vhci_rx)
105		usbip_dump_urb(urb);
106
107	usbip_dbg_vhci_rx("now giveback urb %p\n", urb);
108
109	spin_lock_irqsave(&vhci->lock, flags);
110	usb_hcd_unlink_urb_from_ep(vhci_to_hcd(vhci), urb);
111	spin_unlock_irqrestore(&vhci->lock, flags);
112
113	usb_hcd_giveback_urb(vhci_to_hcd(vhci), urb, urb->status);
114
115	usbip_dbg_vhci_rx("Leave\n");
116}
117
118static struct vhci_unlink *dequeue_pending_unlink(struct vhci_device *vdev,
119						  struct usbip_header *pdu)
120{
121	struct vhci_unlink *unlink, *tmp;
122	unsigned long flags;
123
124	spin_lock_irqsave(&vdev->priv_lock, flags);
125
126	list_for_each_entry_safe(unlink, tmp, &vdev->unlink_rx, list) {
127		pr_info("unlink->seqnum %lu\n", unlink->seqnum);
128		if (unlink->seqnum == pdu->base.seqnum) {
129			usbip_dbg_vhci_rx("found pending unlink, %lu\n",
130					  unlink->seqnum);
131			list_del(&unlink->list);
132
133			spin_unlock_irqrestore(&vdev->priv_lock, flags);
134			return unlink;
135		}
136	}
137
138	spin_unlock_irqrestore(&vdev->priv_lock, flags);
139
140	return NULL;
141}
142
143static void vhci_recv_ret_unlink(struct vhci_device *vdev,
144				 struct usbip_header *pdu)
145{
146	struct vhci_hcd *vhci = vdev_to_vhci(vdev);
147	struct vhci_unlink *unlink;
148	struct urb *urb;
149	unsigned long flags;
150
151	usbip_dump_header(pdu);
152
153	unlink = dequeue_pending_unlink(vdev, pdu);
154	if (!unlink) {
155		pr_info("cannot find the pending unlink %u\n",
156			pdu->base.seqnum);
157		return;
158	}
159
160	spin_lock_irqsave(&vdev->priv_lock, flags);
161	urb = pickup_urb_and_free_priv(vdev, unlink->unlink_seqnum);
162	spin_unlock_irqrestore(&vdev->priv_lock, flags);
163
164	if (!urb) {
165		/*
166		 * I get the result of a unlink request. But, it seems that I
167		 * already received the result of its submit result and gave
168		 * back the URB.
169		 */
170		pr_info("the urb (seqnum %d) was already given back\n",
171			pdu->base.seqnum);
172	} else {
173		usbip_dbg_vhci_rx("now giveback urb %p\n", urb);
174
175		/* If unlink is successful, status is -ECONNRESET */
176		urb->status = pdu->u.ret_unlink.status;
177		pr_info("urb->status %d\n", urb->status);
178
179		spin_lock_irqsave(&vhci->lock, flags);
180		usb_hcd_unlink_urb_from_ep(vhci_to_hcd(vhci), urb);
181		spin_unlock_irqrestore(&vhci->lock, flags);
182
183		usb_hcd_giveback_urb(vhci_to_hcd(vhci), urb, urb->status);
184	}
185
186	kfree(unlink);
187}
188
189static int vhci_priv_tx_empty(struct vhci_device *vdev)
190{
191	int empty = 0;
192	unsigned long flags;
193
194	spin_lock_irqsave(&vdev->priv_lock, flags);
195	empty = list_empty(&vdev->priv_rx);
196	spin_unlock_irqrestore(&vdev->priv_lock, flags);
197
198	return empty;
199}
200
201/* recv a pdu */
202static void vhci_rx_pdu(struct usbip_device *ud)
203{
204	int ret;
205	struct usbip_header pdu;
206	struct vhci_device *vdev = container_of(ud, struct vhci_device, ud);
207
208	usbip_dbg_vhci_rx("Enter\n");
209
210	memset(&pdu, 0, sizeof(pdu));
211
212	/* receive a pdu header */
213	ret = usbip_recv(ud->tcp_socket, &pdu, sizeof(pdu));
214	if (ret < 0) {
215		if (ret == -ECONNRESET)
216			pr_info("connection reset by peer\n");
217		else if (ret == -EAGAIN) {
218			/* ignore if connection was idle */
219			if (vhci_priv_tx_empty(vdev))
220				return;
221			pr_info("connection timed out with pending urbs\n");
222		} else if (ret != -ERESTARTSYS)
223			pr_info("xmit failed %d\n", ret);
224
225		usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
226		return;
227	}
228	if (ret == 0) {
229		pr_info("connection closed");
230		usbip_event_add(ud, VDEV_EVENT_DOWN);
231		return;
232	}
233	if (ret != sizeof(pdu)) {
234		pr_err("received pdu size is %d, should be %d\n", ret,
235		       (unsigned int)sizeof(pdu));
236		usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
237		return;
238	}
239
240	usbip_header_correct_endian(&pdu, 0);
241
242	if (usbip_dbg_flag_vhci_rx)
243		usbip_dump_header(&pdu);
244
245	switch (pdu.base.command) {
246	case USBIP_RET_SUBMIT:
247		vhci_recv_ret_submit(vdev, &pdu);
248		break;
249	case USBIP_RET_UNLINK:
250		vhci_recv_ret_unlink(vdev, &pdu);
251		break;
252	default:
253		/* NOT REACHED */
254		pr_err("unknown pdu %u\n", pdu.base.command);
255		usbip_dump_header(&pdu);
256		usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
257		break;
258	}
259}
260
261int vhci_rx_loop(void *data)
262{
263	struct usbip_device *ud = data;
264
265	while (!kthread_should_stop()) {
266		if (usbip_event_happened(ud))
267			break;
268
269		vhci_rx_pdu(ud);
270	}
271
272	return 0;
273}