summaryrefslogtreecommitdiffstats
path: root/drivers/bluetooth/hci_h4.c
blob: 19ba52005009fdf9c0be865519004e6dce00407f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *
 *  Bluetooth HCI UART driver
 *
 *  Copyright (C) 2000-2001  Qualcomm Incorporated
 *  Copyright (C) 2002-2003  Maxim Krasnyansky <maxk@qualcomm.com>
 *  Copyright (C) 2004-2005  Marcel Holtmann <marcel@holtmann.org>
 */

#include <linux/module.h>

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ptrace.h>
#include <linux/poll.h>

#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/signal.h>
#include <linux/ioctl.h>
#include <linux/skbuff.h>
#include <asm/unaligned.h>

#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>

#include "hci_uart.h"

struct h4_struct {
	struct sk_buff *rx_skb;
	struct sk_buff_head txq;
};

/* Initialize protocol */
static int h4_open(struct hci_uart *hu)
{
	struct h4_struct *h4;

	BT_DBG("hu %p", hu);

	h4 = kzalloc(sizeof(*h4), GFP_KERNEL);
	if (!h4)
		return -ENOMEM;

	skb_queue_head_init(&h4->txq);

	hu->priv = h4;
	return 0;
}

/* Flush protocol data */
static int h4_flush(struct hci_uart *hu)
{
	struct h4_struct *h4 = hu->priv;

	BT_DBG("hu %p", hu);

	skb_queue_purge(&h4->txq);

	return 0;
}

/* Close protocol */
static int h4_close(struct hci_uart *hu)
{
	struct h4_struct *h4 = hu->priv;

	hu->priv = NULL;

	BT_DBG("hu %p", hu);

	skb_queue_purge(&h4->txq);

	kfree_skb(h4->rx_skb);

	hu->priv = NULL;
	kfree(h4);

	return 0;
}

/* Enqueue frame for transmittion (padding, crc, etc) */
static int h4_enqueue(struct hci_uart *hu, struct sk_buff *skb)
{
	struct h4_struct *h4 = hu->priv;

	BT_DBG("hu %p skb %p", hu, skb);

	/* Prepend skb with frame type */
	memcpy(skb_push(skb, 1), &hci_skb_pkt_type(skb), 1);
	skb_queue_tail(&h4->txq, skb);

	return 0;
}

static const struct h4_recv_pkt h4_recv_pkts[] = {
	{ H4_RECV_ACL,   .recv = hci_recv_frame },
	{ H4_RECV_SCO,   .recv = hci_recv_frame },
	{ H4_RECV_EVENT, .recv = hci_recv_frame },
};

/* Recv data */
static int h4_recv(struct hci_uart *hu, const void *data, int count)
{
	struct h4_struct *h4 = hu->priv;

	if (!test_bit(HCI_UART_REGISTERED, &hu->flags))
		return -EUNATCH;

	h4->rx_skb = h4_recv_buf(hu->hdev, h4->rx_skb, data, count,
				 h4_recv_pkts, ARRAY_SIZE(h4_recv_pkts));
	if (IS_ERR(h4->rx_skb)) {
		int err = PTR_ERR(h4->rx_skb);
		bt_dev_err(hu->hdev, "Frame reassembly failed (%d)", err);
		h4->rx_skb = NULL;
		return err;
	}

	return count;
}

static struct sk_buff *h4_dequeue(struct hci_uart *hu)
{
	struct h4_struct *h4 = hu->priv;
	return skb_dequeue(&h4->txq);
}

static const struct hci_uart_proto h4p = {
	.id		= HCI_UART_H4,
	.name		= "H4",
	.open		= h4_open,
	.close		= h4_close,
	.recv		= h4_recv,
	.enqueue	= h4_enqueue,
	.dequeue	= h4_dequeue,
	.flush		= h4_flush,
};

int __init h4_init(void)
{
	return hci_uart_register_proto(&h4p);
}

int __exit h4_deinit(void)
{
	return hci_uart_unregister_proto(&h4p);
}

struct sk_buff *h4_recv_buf(struct hci_dev *hdev, struct sk_buff *skb,
			    const unsigned char *buffer, int count,
			    const struct h4_recv_pkt *pkts, int pkts_count)
{
	struct hci_uart *hu = hci_get_drvdata(hdev);
	u8 alignment = hu->alignment ? hu->alignment : 1;

	/* Check for error from previous call */
	if (IS_ERR(skb))
		skb = NULL;

	while (count) {
		int i, len;

		/* remove padding bytes from buffer */
		for (; hu->padding && count > 0; hu->padding--) {
			count--;
			buffer++;
		}
		if (!count)
			break;

		if (!skb) {
			for (i = 0; i < pkts_count; i++) {
				if (buffer[0] != (&pkts[i])->type)
					continue;

				skb = bt_skb_alloc((&pkts[i])->maxlen,
						   GFP_ATOMIC);
				if (!skb)
					return ERR_PTR(-ENOMEM);

				hci_skb_pkt_type(skb) = (&pkts[i])->type;
				hci_skb_expect(skb) = (&pkts[i])->hlen;
				break;
			}

			/* Check for invalid packet type */
			if (!skb)
				return ERR_PTR(-EILSEQ);

			count -= 1;
			buffer += 1;
		}

		len = min_t(uint, hci_skb_expect(skb) - skb->len, count);
		skb_put_data(skb, buffer, len);

		count -= len;
		buffer += len;

		/* Check for partial packet */
		if (skb->len < hci_skb_expect(skb))
			continue;

		for (i = 0; i < pkts_count; i++) {
			if (hci_skb_pkt_type(skb) == (&pkts[i])->type)
				break;
		}

		if (i >= pkts_count) {
			kfree_skb(skb);
			return ERR_PTR(-EILSEQ);
		}

		if (skb->len == (&pkts[i])->hlen) {
			u16 dlen;

			switch ((&pkts[i])->lsize) {
			case 0:
				/* No variable data length */
				dlen = 0;
				break;
			case 1:
				/* Single octet variable length */
				dlen = skb->data[(&pkts[i])->loff];
				hci_skb_expect(skb) += dlen;

				if (skb_tailroom(skb) < dlen) {
					kfree_skb(skb);
					return ERR_PTR(-EMSGSIZE);
				}
				break;
			case 2:
				/* Double octet variable length */
				dlen = get_unaligned_le16(skb->data +
							  (&pkts[i])->loff);
				hci_skb_expect(skb) += dlen;

				if (skb_tailroom(skb) < dlen) {
					kfree_skb(skb);
					return ERR_PTR(-EMSGSIZE);
				}
				break;
			default:
				/* Unsupported variable length */
				kfree_skb(skb);
				return ERR_PTR(-EILSEQ);
			}

			if (!dlen) {
				hu->padding = (skb->len - 1) % alignment;
				hu->padding = (alignment - hu->padding) % alignment;

				/* No more data, complete frame */
				(&pkts[i])->recv(hdev, skb);
				skb = NULL;
			}
		} else {
			hu->padding = (skb->len - 1) % alignment;
			hu->padding = (alignment - hu->padding) % alignment;

			/* Complete frame */
			(&pkts[i])->recv(hdev, skb);
			skb = NULL;
		}
	}

	return skb;
}
EXPORT_SYMBOL_GPL(h4_recv_buf);