1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 *
4 * Bluetooth HCI UART driver
5 *
6 * Copyright (C) 2000-2001 Qualcomm Incorporated
7 * Copyright (C) 2002-2003 Maxim Krasnyansky <maxk@qualcomm.com>
8 * Copyright (C) 2004-2005 Marcel Holtmann <marcel@holtmann.org>
9 */
10
11 #include <linux/module.h>
12
13 #include <linux/kernel.h>
14 #include <linux/init.h>
15 #include <linux/types.h>
16 #include <linux/fcntl.h>
17 #include <linux/interrupt.h>
18 #include <linux/ptrace.h>
19 #include <linux/poll.h>
20
21 #include <linux/slab.h>
22 #include <linux/tty.h>
23 #include <linux/errno.h>
24 #include <linux/string.h>
25 #include <linux/signal.h>
26 #include <linux/ioctl.h>
27 #include <linux/skbuff.h>
28 #include <linux/unaligned.h>
29
30 #include <net/bluetooth/bluetooth.h>
31 #include <net/bluetooth/hci_core.h>
32
33 #include "hci_uart.h"
34
35 struct h4_struct {
36 struct sk_buff *rx_skb;
37 struct sk_buff_head txq;
38 };
39
40 /* Initialize protocol */
h4_open(struct hci_uart * hu)41 static int h4_open(struct hci_uart *hu)
42 {
43 struct h4_struct *h4;
44
45 BT_DBG("hu %p", hu);
46
47 h4 = kzalloc_obj(*h4);
48 if (!h4)
49 return -ENOMEM;
50
51 skb_queue_head_init(&h4->txq);
52
53 hu->priv = h4;
54 return 0;
55 }
56
57 /* Flush protocol data */
h4_flush(struct hci_uart * hu)58 static int h4_flush(struct hci_uart *hu)
59 {
60 struct h4_struct *h4 = hu->priv;
61
62 BT_DBG("hu %p", hu);
63
64 skb_queue_purge(&h4->txq);
65
66 return 0;
67 }
68
69 /* Close protocol */
h4_close(struct hci_uart * hu)70 static int h4_close(struct hci_uart *hu)
71 {
72 struct h4_struct *h4 = hu->priv;
73
74 BT_DBG("hu %p", hu);
75
76 skb_queue_purge(&h4->txq);
77
78 kfree_skb(h4->rx_skb);
79
80 hu->priv = NULL;
81 kfree(h4);
82
83 return 0;
84 }
85
86 /* Enqueue frame for transmission (padding, crc, etc) */
h4_enqueue(struct hci_uart * hu,struct sk_buff * skb)87 static int h4_enqueue(struct hci_uart *hu, struct sk_buff *skb)
88 {
89 struct h4_struct *h4 = hu->priv;
90
91 BT_DBG("hu %p skb %p", hu, skb);
92
93 /* Prepend skb with frame type */
94 memcpy(skb_push(skb, 1), &hci_skb_pkt_type(skb), 1);
95 skb_queue_tail(&h4->txq, skb);
96
97 return 0;
98 }
99
100 static const struct h4_recv_pkt h4_recv_pkts[] = {
101 { H4_RECV_ACL, .recv = hci_recv_frame },
102 { H4_RECV_SCO, .recv = hci_recv_frame },
103 { H4_RECV_EVENT, .recv = hci_recv_frame },
104 { H4_RECV_ISO, .recv = hci_recv_frame },
105 };
106
107 /* Recv data */
h4_recv(struct hci_uart * hu,const void * data,int count)108 static int h4_recv(struct hci_uart *hu, const void *data, int count)
109 {
110 struct h4_struct *h4 = hu->priv;
111
112 h4->rx_skb = h4_recv_buf(hu, h4->rx_skb, data, count,
113 h4_recv_pkts, ARRAY_SIZE(h4_recv_pkts));
114 if (IS_ERR(h4->rx_skb)) {
115 int err = PTR_ERR(h4->rx_skb);
116 bt_dev_err(hu->hdev, "Frame reassembly failed (%d)", err);
117 h4->rx_skb = NULL;
118 return err;
119 }
120
121 return count;
122 }
123
h4_dequeue(struct hci_uart * hu)124 static struct sk_buff *h4_dequeue(struct hci_uart *hu)
125 {
126 struct h4_struct *h4 = hu->priv;
127 return skb_dequeue(&h4->txq);
128 }
129
130 static const struct hci_uart_proto h4p = {
131 .id = HCI_UART_H4,
132 .name = "H4",
133 .open = h4_open,
134 .close = h4_close,
135 .recv = h4_recv,
136 .enqueue = h4_enqueue,
137 .dequeue = h4_dequeue,
138 .flush = h4_flush,
139 };
140
h4_init(void)141 int __init h4_init(void)
142 {
143 return hci_uart_register_proto(&h4p);
144 }
145
h4_deinit(void)146 int __exit h4_deinit(void)
147 {
148 return hci_uart_unregister_proto(&h4p);
149 }
150
h4_recv_buf(struct hci_uart * hu,struct sk_buff * skb,const unsigned char * buffer,int count,const struct h4_recv_pkt * pkts,int pkts_count)151 struct sk_buff *h4_recv_buf(struct hci_uart *hu, struct sk_buff *skb,
152 const unsigned char *buffer, int count,
153 const struct h4_recv_pkt *pkts, int pkts_count)
154 {
155 u8 alignment = hu->alignment ? hu->alignment : 1;
156 struct hci_dev *hdev = hu->hdev;
157
158 /* Check for error from previous call */
159 if (IS_ERR(skb))
160 skb = NULL;
161
162 while (count) {
163 int i, len;
164
165 /* remove padding bytes from buffer */
166 for (; hu->padding && count > 0; hu->padding--) {
167 count--;
168 buffer++;
169 }
170 if (!count)
171 break;
172
173 if (!skb) {
174 for (i = 0; i < pkts_count; i++) {
175 if (buffer[0] != (&pkts[i])->type)
176 continue;
177
178 skb = bt_skb_alloc((&pkts[i])->maxlen,
179 GFP_ATOMIC);
180 if (!skb)
181 return ERR_PTR(-ENOMEM);
182
183 hci_skb_pkt_type(skb) = (&pkts[i])->type;
184 hci_skb_expect(skb) = (&pkts[i])->hlen;
185 break;
186 }
187
188 /* Check for invalid packet type */
189 if (!skb)
190 return ERR_PTR(-EILSEQ);
191
192 count -= 1;
193 buffer += 1;
194 }
195
196 len = min_t(uint, hci_skb_expect(skb) - skb->len, count);
197 skb_put_data(skb, buffer, len);
198
199 count -= len;
200 buffer += len;
201
202 /* Check for partial packet */
203 if (skb->len < hci_skb_expect(skb))
204 continue;
205
206 for (i = 0; i < pkts_count; i++) {
207 if (hci_skb_pkt_type(skb) == (&pkts[i])->type)
208 break;
209 }
210
211 if (i >= pkts_count) {
212 kfree_skb(skb);
213 return ERR_PTR(-EILSEQ);
214 }
215
216 if (skb->len == (&pkts[i])->hlen) {
217 u16 dlen;
218
219 switch ((&pkts[i])->lsize) {
220 case 0:
221 /* No variable data length */
222 dlen = 0;
223 break;
224 case 1:
225 /* Single octet variable length */
226 dlen = skb->data[(&pkts[i])->loff];
227 hci_skb_expect(skb) += dlen;
228
229 if (skb_tailroom(skb) < dlen) {
230 kfree_skb(skb);
231 return ERR_PTR(-EMSGSIZE);
232 }
233 break;
234 case 2:
235 /* Double octet variable length */
236 dlen = get_unaligned_le16(skb->data +
237 (&pkts[i])->loff);
238 hci_skb_expect(skb) += dlen;
239
240 if (skb_tailroom(skb) < dlen) {
241 kfree_skb(skb);
242 return ERR_PTR(-EMSGSIZE);
243 }
244 break;
245 default:
246 /* Unsupported variable length */
247 kfree_skb(skb);
248 return ERR_PTR(-EILSEQ);
249 }
250
251 if (!dlen) {
252 hu->padding = (skb->len + 1) % alignment;
253 hu->padding = (alignment - hu->padding) % alignment;
254
255 /* No more data, complete frame */
256 (&pkts[i])->recv(hdev, skb);
257 skb = NULL;
258 }
259 } else {
260 hu->padding = (skb->len + 1) % alignment;
261 hu->padding = (alignment - hu->padding) % alignment;
262
263 /* Complete frame */
264 (&pkts[i])->recv(hdev, skb);
265 skb = NULL;
266 }
267 }
268
269 return skb;
270 }
271 EXPORT_SYMBOL_GPL(h4_recv_buf);
272