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