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 usbip_device *ud = &vdev->ud;
 74	struct urb *urb;
 75	unsigned long flags;
 76
 77	spin_lock_irqsave(&vdev->priv_lock, flags);
 78	urb = pickup_urb_and_free_priv(vdev, pdu->base.seqnum);
 79	spin_unlock_irqrestore(&vdev->priv_lock, flags);
 80
 81	if (!urb) {
 82		pr_err("cannot find a urb of seqnum %u\n", pdu->base.seqnum);
 83		pr_info("max seqnum %d\n",
 84			atomic_read(&the_controller->seqnum));
 85		usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
 86		return;
 87	}
 88
 89	/* unpack the pdu to a urb */
 90	usbip_pack_pdu(pdu, urb, USBIP_RET_SUBMIT, 0);
 91
 92	/* recv transfer buffer */
 93	if (usbip_recv_xbuff(ud, urb) < 0)
 94		return;
 95
 96	/* recv iso_packet_descriptor */
 97	if (usbip_recv_iso(ud, urb) < 0)
 98		return;
 99
100	/* restore the padding in iso packets */
101	usbip_pad_iso(ud, urb);
102
103	if (usbip_dbg_flag_vhci_rx)
104		usbip_dump_urb(urb);
105
106	usbip_dbg_vhci_rx("now giveback urb %p\n", urb);
107
108	spin_lock_irqsave(&the_controller->lock, flags);
109	usb_hcd_unlink_urb_from_ep(vhci_to_hcd(the_controller), urb);
110	spin_unlock_irqrestore(&the_controller->lock, flags);
111
112	usb_hcd_giveback_urb(vhci_to_hcd(the_controller), urb, urb->status);
113
114	usbip_dbg_vhci_rx("Leave\n");
115}
116
117static struct vhci_unlink *dequeue_pending_unlink(struct vhci_device *vdev,
118						  struct usbip_header *pdu)
119{
120	struct vhci_unlink *unlink, *tmp;
121	unsigned long flags;
122
123	spin_lock_irqsave(&vdev->priv_lock, flags);
124
125	list_for_each_entry_safe(unlink, tmp, &vdev->unlink_rx, list) {
126		pr_info("unlink->seqnum %lu\n", unlink->seqnum);
127		if (unlink->seqnum == pdu->base.seqnum) {
128			usbip_dbg_vhci_rx("found pending unlink, %lu\n",
129					  unlink->seqnum);
130			list_del(&unlink->list);
131
132			spin_unlock_irqrestore(&vdev->priv_lock, flags);
133			return unlink;
134		}
135	}
136
137	spin_unlock_irqrestore(&vdev->priv_lock, flags);
138
139	return NULL;
140}
141
142static void vhci_recv_ret_unlink(struct vhci_device *vdev,
143				 struct usbip_header *pdu)
144{
145	struct vhci_unlink *unlink;
146	struct urb *urb;
147	unsigned long flags;
148
149	usbip_dump_header(pdu);
150
151	unlink = dequeue_pending_unlink(vdev, pdu);
152	if (!unlink) {
153		pr_info("cannot find the pending unlink %u\n",
154			pdu->base.seqnum);
155		return;
156	}
157
158	spin_lock_irqsave(&vdev->priv_lock, flags);
159	urb = pickup_urb_and_free_priv(vdev, unlink->unlink_seqnum);
160	spin_unlock_irqrestore(&vdev->priv_lock, flags);
161
162	if (!urb) {
163		/*
164		 * I get the result of a unlink request. But, it seems that I
165		 * already received the result of its submit result and gave
166		 * back the URB.
167		 */
168		pr_info("the urb (seqnum %d) was already given back\n",
169			pdu->base.seqnum);
170	} else {
171		usbip_dbg_vhci_rx("now giveback urb %p\n", urb);
172
173		/* If unlink is successful, status is -ECONNRESET */
174		urb->status = pdu->u.ret_unlink.status;
175		pr_info("urb->status %d\n", urb->status);
176
177		spin_lock_irqsave(&the_controller->lock, flags);
178		usb_hcd_unlink_urb_from_ep(vhci_to_hcd(the_controller), urb);
179		spin_unlock_irqrestore(&the_controller->lock, flags);
180
181		usb_hcd_giveback_urb(vhci_to_hcd(the_controller), urb,
182				     urb->status);
183	}
184
185	kfree(unlink);
186}
187
188static int vhci_priv_tx_empty(struct vhci_device *vdev)
189{
190	int empty = 0;
191	unsigned long flags;
192
193	spin_lock_irqsave(&vdev->priv_lock, flags);
194	empty = list_empty(&vdev->priv_rx);
195	spin_unlock_irqrestore(&vdev->priv_lock, flags);
196
197	return empty;
198}
199
200/* recv a pdu */
201static void vhci_rx_pdu(struct usbip_device *ud)
202{
203	int ret;
204	struct usbip_header pdu;
205	struct vhci_device *vdev = container_of(ud, struct vhci_device, ud);
206
207	usbip_dbg_vhci_rx("Enter\n");
208
209	memset(&pdu, 0, sizeof(pdu));
210
211	/* receive a pdu header */
212	ret = usbip_recv(ud->tcp_socket, &pdu, sizeof(pdu));
213	if (ret < 0) {
214		if (ret == -ECONNRESET)
215			pr_info("connection reset by peer\n");
216		else if (ret == -EAGAIN) {
217			/* ignore if connection was idle */
218			if (vhci_priv_tx_empty(vdev))
219				return;
220			pr_info("connection timed out with pending urbs\n");
221		} else if (ret != -ERESTARTSYS)
222			pr_info("xmit failed %d\n", ret);
223
224		usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
225		return;
226	}
227	if (ret == 0) {
228		pr_info("connection closed");
229		usbip_event_add(ud, VDEV_EVENT_DOWN);
230		return;
231	}
232	if (ret != sizeof(pdu)) {
233		pr_err("received pdu size is %d, should be %d\n", ret,
234		       (unsigned int)sizeof(pdu));
235		usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
236		return;
237	}
238
239	usbip_header_correct_endian(&pdu, 0);
240
241	if (usbip_dbg_flag_vhci_rx)
242		usbip_dump_header(&pdu);
243
244	switch (pdu.base.command) {
245	case USBIP_RET_SUBMIT:
246		vhci_recv_ret_submit(vdev, &pdu);
247		break;
248	case USBIP_RET_UNLINK:
249		vhci_recv_ret_unlink(vdev, &pdu);
250		break;
251	default:
252		/* NOT REACHED */
253		pr_err("unknown pdu %u\n", pdu.base.command);
254		usbip_dump_header(&pdu);
255		usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
256		break;
257	}
258}
259
260int vhci_rx_loop(void *data)
261{
262	struct usbip_device *ud = data;
263
264	while (!kthread_should_stop()) {
265		if (usbip_event_happened(ud))
266			break;
267
268		vhci_rx_pdu(ud);
269	}
270
271	return 0;
272}