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 fallthrough;
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(entry: &priv->list);
46 kfree(objp: 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, seqnum: pdu->base.seqnum);
66 spin_unlock_irqrestore(lock: &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, pack: 0);
78
79 /* recv transfer buffer */
80 if (usbip_recv_xbuff(ud, urb) < 0) {
81 urb->status = -EPROTO;
82 goto error;
83 }
84
85 /* recv iso_packet_descriptor */
86 if (usbip_recv_iso(ud, urb) < 0) {
87 urb->status = -EPROTO;
88 goto error;
89 }
90
91 /* restore the padding in iso packets */
92 usbip_pad_iso(ud, urb);
93
94error:
95 if (usbip_dbg_flag_vhci_rx)
96 usbip_dump_urb(purb: urb);
97
98 if (urb->num_sgs)
99 urb->transfer_flags &= ~URB_DMA_MAP_SG;
100
101 usbip_dbg_vhci_rx("now giveback urb %u\n", pdu->base.seqnum);
102
103 spin_lock_irqsave(&vhci->lock, flags);
104 usb_hcd_unlink_urb_from_ep(hcd: vhci_hcd_to_hcd(vhci_hcd), urb);
105 spin_unlock_irqrestore(lock: &vhci->lock, flags);
106
107 usb_hcd_giveback_urb(hcd: vhci_hcd_to_hcd(vhci_hcd), urb, status: urb->status);
108
109 usbip_dbg_vhci_rx("Leave\n");
110}
111
112static struct vhci_unlink *dequeue_pending_unlink(struct vhci_device *vdev,
113 struct usbip_header *pdu)
114{
115 struct vhci_unlink *unlink, *tmp;
116 unsigned long flags;
117
118 spin_lock_irqsave(&vdev->priv_lock, flags);
119
120 list_for_each_entry_safe(unlink, tmp, &vdev->unlink_rx, list) {
121 pr_info("unlink->seqnum %lu\n", unlink->seqnum);
122 if (unlink->seqnum == pdu->base.seqnum) {
123 usbip_dbg_vhci_rx("found pending unlink, %lu\n",
124 unlink->seqnum);
125 list_del(entry: &unlink->list);
126
127 spin_unlock_irqrestore(lock: &vdev->priv_lock, flags);
128 return unlink;
129 }
130 }
131
132 spin_unlock_irqrestore(lock: &vdev->priv_lock, flags);
133
134 return NULL;
135}
136
137static void vhci_recv_ret_unlink(struct vhci_device *vdev,
138 struct usbip_header *pdu)
139{
140 struct vhci_hcd *vhci_hcd = vdev_to_vhci_hcd(vdev);
141 struct vhci *vhci = vhci_hcd->vhci;
142 struct vhci_unlink *unlink;
143 struct urb *urb;
144 unsigned long flags;
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_irqsave(&vdev->priv_lock, flags);
156 urb = pickup_urb_and_free_priv(vdev, seqnum: unlink->unlink_seqnum);
157 spin_unlock_irqrestore(lock: &vdev->priv_lock, flags);
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 %d\n", pdu->base.seqnum);
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_irqsave(&vhci->lock, flags);
175 usb_hcd_unlink_urb_from_ep(hcd: vhci_hcd_to_hcd(vhci_hcd), urb);
176 spin_unlock_irqrestore(lock: &vhci->lock, flags);
177
178 usb_hcd_giveback_urb(hcd: vhci_hcd_to_hcd(vhci_hcd), urb, status: urb->status);
179 }
180
181 kfree(objp: unlink);
182}
183
184static int vhci_priv_tx_empty(struct vhci_device *vdev)
185{
186 int empty = 0;
187 unsigned long flags;
188
189 spin_lock_irqsave(&vdev->priv_lock, flags);
190 empty = list_empty(head: &vdev->priv_rx);
191 spin_unlock_irqrestore(lock: &vdev->priv_lock, flags);
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(sock: ud->tcp_socket, buf: &pdu, size: 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: &pdu, send: 0);
236
237 if (usbip_dbg_flag_vhci_rx)
238 usbip_dump_header(pdu: &pdu);
239
240 switch (pdu.base.command) {
241 case USBIP_RET_SUBMIT:
242 vhci_recv_ret_submit(vdev, pdu: &pdu);
243 break;
244 case USBIP_RET_UNLINK:
245 vhci_recv_ret_unlink(vdev, pdu: &pdu);
246 break;
247 default:
248 /* NOT REACHED */
249 pr_err("unknown pdu %u\n", pdu.base.command);
250 usbip_dump_header(pdu: &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 usbip_kcov_remote_start(ud);
265 vhci_rx_pdu(ud);
266 usbip_kcov_remote_stop();
267 }
268
269 return 0;
270}
271

source code of linux/drivers/usb/usbip/vhci_rx.c