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