1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * Copyright (C) 2003-2008 Takahiro Hirofuchi
  4 */
  5
  6#include <linux/kthread.h>
  7#include <linux/slab.h>
  8
  9#include "usbip_common.h"
 10#include "vhci.h"
 11
 12/* get URB from transmitted urb queue. caller must hold vdev->priv_lock */
 13struct urb *pickup_urb_and_free_priv(struct vhci_device *vdev, __u32 seqnum)
 14{
 15	struct vhci_priv *priv, *tmp;
 16	struct urb *urb = NULL;
 17	int status;
 18
 19	list_for_each_entry_safe(priv, tmp, &vdev->priv_rx, list) {
 20		if (priv->seqnum != seqnum)
 21			continue;
 22
 23		urb = priv->urb;
 24		status = urb->status;
 25
 26		usbip_dbg_vhci_rx("find urb seqnum %u\n", seqnum);
 27
 28		switch (status) {
 29		case -ENOENT:
 30			/* fall through */
 31		case -ECONNRESET:
 32			dev_dbg(&urb->dev->dev,
 33				 "urb seq# %u was unlinked %ssynchronously\n",
 34				 seqnum, status == -ENOENT ? "" : "a");
 35			break;
 36		case -EINPROGRESS:
 37			/* no info output */
 38			break;
 39		default:
 40			dev_dbg(&urb->dev->dev,
 41				 "urb seq# %u may be in a error, status %d\n",
 42				 seqnum, status);
 43		}
 44
 45		list_del(&priv->list);
 46		kfree(priv);
 47		urb->hcpriv = NULL;
 48
 49		break;
 50	}
 51
 52	return urb;
 53}
 54
 55static void vhci_recv_ret_submit(struct vhci_device *vdev,
 56				 struct usbip_header *pdu)
 57{
 58	struct vhci_hcd *vhci_hcd = vdev_to_vhci_hcd(vdev);
 59	struct vhci *vhci = vhci_hcd->vhci;
 60	struct usbip_device *ud = &vdev->ud;
 61	struct urb *urb;
 62	unsigned long flags;
 63
 64	spin_lock_irqsave(&vdev->priv_lock, flags);
 65	urb = pickup_urb_and_free_priv(vdev, pdu->base.seqnum);
 66	spin_unlock_irqrestore(&vdev->priv_lock, flags);
 67
 68	if (!urb) {
 69		pr_err("cannot find a urb of seqnum %u max seqnum %d\n",
 70			pdu->base.seqnum,
 71			atomic_read(&vhci_hcd->seqnum));
 72		usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
 73		return;
 74	}
 75
 76	/* unpack the pdu to a urb */
 77	usbip_pack_pdu(pdu, urb, USBIP_RET_SUBMIT, 0);
 78
 79	/* recv transfer buffer */
 80	if (usbip_recv_xbuff(ud, urb) < 0)
 81		return;
 82
 83	/* recv iso_packet_descriptor */
 84	if (usbip_recv_iso(ud, urb) < 0)
 85		return;
 86
 87	/* restore the padding in iso packets */
 88	usbip_pad_iso(ud, urb);
 89
 90	if (usbip_dbg_flag_vhci_rx)
 91		usbip_dump_urb(urb);
 92
 93	usbip_dbg_vhci_rx("now giveback urb %u\n", pdu->base.seqnum);
 94
 95	spin_lock_irqsave(&vhci->lock, flags);
 96	usb_hcd_unlink_urb_from_ep(vhci_hcd_to_hcd(vhci_hcd), urb);
 97	spin_unlock_irqrestore(&vhci->lock, flags);
 98
 99	usb_hcd_giveback_urb(vhci_hcd_to_hcd(vhci_hcd), urb, urb->status);
100
101	usbip_dbg_vhci_rx("Leave\n");
102}
103
104static struct vhci_unlink *dequeue_pending_unlink(struct vhci_device *vdev,
105						  struct usbip_header *pdu)
106{
107	struct vhci_unlink *unlink, *tmp;
108	unsigned long flags;
109
110	spin_lock_irqsave(&vdev->priv_lock, flags);
111
112	list_for_each_entry_safe(unlink, tmp, &vdev->unlink_rx, list) {
113		pr_info("unlink->seqnum %lu\n", unlink->seqnum);
114		if (unlink->seqnum == pdu->base.seqnum) {
115			usbip_dbg_vhci_rx("found pending unlink, %lu\n",
116					  unlink->seqnum);
117			list_del(&unlink->list);
118
119			spin_unlock_irqrestore(&vdev->priv_lock, flags);
120			return unlink;
121		}
122	}
123
124	spin_unlock_irqrestore(&vdev->priv_lock, flags);
125
126	return NULL;
127}
128
129static void vhci_recv_ret_unlink(struct vhci_device *vdev,
130				 struct usbip_header *pdu)
131{
132	struct vhci_hcd *vhci_hcd = vdev_to_vhci_hcd(vdev);
133	struct vhci *vhci = vhci_hcd->vhci;
134	struct vhci_unlink *unlink;
135	struct urb *urb;
136	unsigned long flags;
137
138	usbip_dump_header(pdu);
139
140	unlink = dequeue_pending_unlink(vdev, pdu);
141	if (!unlink) {
142		pr_info("cannot find the pending unlink %u\n",
143			pdu->base.seqnum);
144		return;
145	}
146
147	spin_lock_irqsave(&vdev->priv_lock, flags);
148	urb = pickup_urb_and_free_priv(vdev, unlink->unlink_seqnum);
149	spin_unlock_irqrestore(&vdev->priv_lock, flags);
150
151	if (!urb) {
152		/*
153		 * I get the result of a unlink request. But, it seems that I
154		 * already received the result of its submit result and gave
155		 * back the URB.
156		 */
157		pr_info("the urb (seqnum %d) was already given back\n",
158			pdu->base.seqnum);
159	} else {
160		usbip_dbg_vhci_rx("now giveback urb %d\n", pdu->base.seqnum);
161
162		/* If unlink is successful, status is -ECONNRESET */
163		urb->status = pdu->u.ret_unlink.status;
164		pr_info("urb->status %d\n", urb->status);
165
166		spin_lock_irqsave(&vhci->lock, flags);
167		usb_hcd_unlink_urb_from_ep(vhci_hcd_to_hcd(vhci_hcd), urb);
168		spin_unlock_irqrestore(&vhci->lock, flags);
169
170		usb_hcd_giveback_urb(vhci_hcd_to_hcd(vhci_hcd), urb, urb->status);
171	}
172
173	kfree(unlink);
174}
175
176static int vhci_priv_tx_empty(struct vhci_device *vdev)
177{
178	int empty = 0;
179	unsigned long flags;
180
181	spin_lock_irqsave(&vdev->priv_lock, flags);
182	empty = list_empty(&vdev->priv_rx);
183	spin_unlock_irqrestore(&vdev->priv_lock, flags);
184
185	return empty;
186}
187
188/* recv a pdu */
189static void vhci_rx_pdu(struct usbip_device *ud)
190{
191	int ret;
192	struct usbip_header pdu;
193	struct vhci_device *vdev = container_of(ud, struct vhci_device, ud);
194
195	usbip_dbg_vhci_rx("Enter\n");
196
197	memset(&pdu, 0, sizeof(pdu));
198
199	/* receive a pdu header */
200	ret = usbip_recv(ud->tcp_socket, &pdu, sizeof(pdu));
201	if (ret < 0) {
202		if (ret == -ECONNRESET)
203			pr_info("connection reset by peer\n");
204		else if (ret == -EAGAIN) {
205			/* ignore if connection was idle */
206			if (vhci_priv_tx_empty(vdev))
207				return;
208			pr_info("connection timed out with pending urbs\n");
209		} else if (ret != -ERESTARTSYS)
210			pr_info("xmit failed %d\n", ret);
211
212		usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
213		return;
214	}
215	if (ret == 0) {
216		pr_info("connection closed");
217		usbip_event_add(ud, VDEV_EVENT_DOWN);
218		return;
219	}
220	if (ret != sizeof(pdu)) {
221		pr_err("received pdu size is %d, should be %d\n", ret,
222		       (unsigned int)sizeof(pdu));
223		usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
224		return;
225	}
226
227	usbip_header_correct_endian(&pdu, 0);
228
229	if (usbip_dbg_flag_vhci_rx)
230		usbip_dump_header(&pdu);
231
232	switch (pdu.base.command) {
233	case USBIP_RET_SUBMIT:
234		vhci_recv_ret_submit(vdev, &pdu);
235		break;
236	case USBIP_RET_UNLINK:
237		vhci_recv_ret_unlink(vdev, &pdu);
238		break;
239	default:
240		/* NOT REACHED */
241		pr_err("unknown pdu %u\n", pdu.base.command);
242		usbip_dump_header(&pdu);
243		usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
244		break;
245	}
246}
247
248int vhci_rx_loop(void *data)
249{
250	struct usbip_device *ud = data;
251
252	while (!kthread_should_stop()) {
253		if (usbip_event_happened(ud))
254			break;
255
256		vhci_rx_pdu(ud);
257	}
258
259	return 0;
260}