drivers/bluetooth/hci_h4.c

   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 <asm/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 */
  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(sizeof(*h4), GFP_KERNEL);
  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 */
  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 */
  70 static int h4_close(struct hci_uart *hu)
  71 {
  72         struct h4_struct *h4 = hu->priv;
  73
  74         hu->priv = NULL;
  75
  76         BT_DBG("hu %p", hu);
  77
  78         skb_queue_purge(&h4->txq);
  79
  80         kfree_skb(h4->rx_skb);
  81
  82         hu->priv = NULL;
  83         kfree(h4);
  84
  85         return 0;
  86 }
  87
  88 /* Enqueue frame for transmittion (padding, crc, etc) */
  89 static int h4_enqueue(struct hci_uart *hu, struct sk_buff *skb)
  90 {
  91         struct h4_struct *h4 = hu->priv;
  92
  93         BT_DBG("hu %p skb %p", hu, skb);
  94
  95         /* Prepend skb with frame type */
  96         memcpy(skb_push(skb, 1), &hci_skb_pkt_type(skb), 1);
  97         skb_queue_tail(&h4->txq, skb);
  98
  99         return 0;
 100 }
 101
 102 static const struct h4_recv_pkt h4_recv_pkts[] = {
 103         { H4_RECV_ACL,   .recv = hci_recv_frame },
 104         { H4_RECV_SCO,   .recv = hci_recv_frame },
 105         { H4_RECV_EVENT, .recv = hci_recv_frame },
 106         { H4_RECV_ISO,   .recv = hci_recv_frame },
 107 };
 108
 109 /* Recv data */
 110 static int h4_recv(struct hci_uart *hu, const void *data, int count)
 111 {
 112         struct h4_struct *h4 = hu->priv;
 113
 114         if (!test_bit(HCI_UART_REGISTERED, &hu->flags))
 115                 return -EUNATCH;
 116
 117         h4->rx_skb = h4_recv_buf(hu->hdev, h4->rx_skb, data, count,
 118                                  h4_recv_pkts, ARRAY_SIZE(h4_recv_pkts));
 119         if (IS_ERR(h4->rx_skb)) {
 120                 int err = PTR_ERR(h4->rx_skb);
 121                 bt_dev_err(hu->hdev, "Frame reassembly failed (%d)", err);
 122                 h4->rx_skb = NULL;
 123                 return err;
 124         }
 125
 126         return count;
 127 }
 128
 129 static struct sk_buff *h4_dequeue(struct hci_uart *hu)
 130 {
 131         struct h4_struct *h4 = hu->priv;
 132         return skb_dequeue(&h4->txq);
 133 }
 134
 135 static const struct hci_uart_proto h4p = {
 136         .id             = HCI_UART_H4,
 137         .name           = "H4",
 138         .open           = h4_open,
 139         .close          = h4_close,
 140         .recv           = h4_recv,
 141         .enqueue        = h4_enqueue,
 142         .dequeue        = h4_dequeue,
 143         .flush          = h4_flush,
 144 };
 145
 146 int __init h4_init(void)
 147 {
 148         return hci_uart_register_proto(&h4p);
 149 }
 150
 151 int __exit h4_deinit(void)
 152 {
 153         return hci_uart_unregister_proto(&h4p);
 154 }
 155
 156 struct sk_buff *h4_recv_buf(struct hci_dev *hdev, struct sk_buff *skb,
 157                             const unsigned char *buffer, int count,
 158                             const struct h4_recv_pkt *pkts, int pkts_count)
 159 {
 160         struct hci_uart *hu = hci_get_drvdata(hdev);
 161         u8 alignment = hu->alignment ? hu->alignment : 1;
 162
 163         /* Check for error from previous call */
 164         if (IS_ERR(skb))
 165                 skb = NULL;
 166
 167         while (count) {
 168                 int i, len;
 169
 170                 /* remove padding bytes from buffer */
 171                 for (; hu->padding && count > 0; hu->padding--) {
 172                         count--;
 173                         buffer++;
 174                 }
 175                 if (!count)
 176                         break;
 177
 178                 if (!skb) {
 179                         for (i = 0; i < pkts_count; i++) {
 180                                 if (buffer[0] != (&pkts[i])->type)
 181                                         continue;
 182
 183                                 skb = bt_skb_alloc((&pkts[i])->maxlen,
 184                                                    GFP_ATOMIC);
 185                                 if (!skb)
 186                                         return ERR_PTR(-ENOMEM);
 187
 188                                 hci_skb_pkt_type(skb) = (&pkts[i])->type;
 189                                 hci_skb_expect(skb) = (&pkts[i])->hlen;
 190                                 break;
 191                         }
 192
 193                         /* Check for invalid packet type */
 194                         if (!skb)
 195                                 return ERR_PTR(-EILSEQ);
 196
 197                         count -= 1;
 198                         buffer += 1;
 199                 }
 200
 201                 len = min_t(uint, hci_skb_expect(skb) - skb->len, count);
 202                 skb_put_data(skb, buffer, len);
 203
 204                 count -= len;
 205                 buffer += len;
 206
 207                 /* Check for partial packet */
 208                 if (skb->len < hci_skb_expect(skb))
 209                         continue;
 210
 211                 for (i = 0; i < pkts_count; i++) {
 212                         if (hci_skb_pkt_type(skb) == (&pkts[i])->type)
 213                                 break;
 214                 }
 215
 216                 if (i >= pkts_count) {
 217                         kfree_skb(skb);
 218                         return ERR_PTR(-EILSEQ);
 219                 }
 220
 221                 if (skb->len == (&pkts[i])->hlen) {
 222                         u16 dlen;
 223
 224                         switch ((&pkts[i])->lsize) {
 225                         case 0:
 226                                 /* No variable data length */
 227                                 dlen = 0;
 228                                 break;
 229                         case 1:
 230                                 /* Single octet variable length */
 231                                 dlen = skb->data[(&pkts[i])->loff];
 232                                 hci_skb_expect(skb) += dlen;
 233
 234                                 if (skb_tailroom(skb) < dlen) {
 235                                         kfree_skb(skb);
 236                                         return ERR_PTR(-EMSGSIZE);
 237                                 }
 238                                 break;
 239                         case 2:
 240                                 /* Double octet variable length */
 241                                 dlen = get_unaligned_le16(skb->data +
 242                                                           (&pkts[i])->loff);
 243                                 hci_skb_expect(skb) += dlen;
 244
 245                                 if (skb_tailroom(skb) < dlen) {
 246                                         kfree_skb(skb);
 247                                         return ERR_PTR(-EMSGSIZE);
 248                                 }
 249                                 break;
 250                         default:
 251                                 /* Unsupported variable length */
 252                                 kfree_skb(skb);
 253                                 return ERR_PTR(-EILSEQ);
 254                         }
 255
 256                         if (!dlen) {
 257                                 hu->padding = (skb->len - 1) % alignment;
 258                                 hu->padding = (alignment - hu->padding) % alignment;
 259
 260                                 /* No more data, complete frame */
 261                                 (&pkts[i])->recv(hdev, skb);
 262                                 skb = NULL;
 263                         }
 264                 } else {
 265                         hu->padding = (skb->len - 1) % alignment;
 266                         hu->padding = (alignment - hu->padding) % alignment;
 267
 268                         /* Complete frame */
 269                         (&pkts[i])->recv(hdev, skb);
 270                         skb = NULL;
 271                 }
 272         }
 273
 274         return skb;
 275 }
 276 EXPORT_SYMBOL_GPL(h4_recv_buf);