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 <[email protected]>
   8  *  Copyright (C) 2004-2005  Marcel Holtmann <[email protected]>
   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 };
 107
 108 /* Recv data */
 109 static int h4_recv(struct hci_uart *hu, const void *data, int count)
 110 {
 111         struct h4_struct *h4 = hu->priv;
 112
 113         if (!test_bit(HCI_UART_REGISTERED, &hu->flags))
 114                 return -EUNATCH;
 115
 116         h4->rx_skb = h4_recv_buf(hu->hdev, h4->rx_skb, data, count,
 117                                  h4_recv_pkts, ARRAY_SIZE(h4_recv_pkts));
 118         if (IS_ERR(h4->rx_skb)) {
 119                 int err = PTR_ERR(h4->rx_skb);
 120                 bt_dev_err(hu->hdev, "Frame reassembly failed (%d)", err);
 121                 h4->rx_skb = NULL;
 122                 return err;
 123         }
 124
 125         return count;
 126 }
 127
 128 static struct sk_buff *h4_dequeue(struct hci_uart *hu)
 129 {
 130         struct h4_struct *h4 = hu->priv;
 131         return skb_dequeue(&h4->txq);
 132 }
 133
 134 static const struct hci_uart_proto h4p = {
 135         .id             = HCI_UART_H4,
 136         .name           = "H4",
 137         .open           = h4_open,
 138         .close          = h4_close,
 139         .recv           = h4_recv,
 140         .enqueue        = h4_enqueue,
 141         .dequeue        = h4_dequeue,
 142         .flush          = h4_flush,
 143 };
 144
 145 int __init h4_init(void)
 146 {
 147         return hci_uart_register_proto(&h4p);
 148 }
 149
 150 int __exit h4_deinit(void)
 151 {
 152         return hci_uart_unregister_proto(&h4p);
 153 }
 154
 155 struct sk_buff *h4_recv_buf(struct hci_dev *hdev, struct sk_buff *skb,
 156                             const unsigned char *buffer, int count,
 157                             const struct h4_recv_pkt *pkts, int pkts_count)
 158 {
 159         struct hci_uart *hu = hci_get_drvdata(hdev);
 160         u8 alignment = hu->alignment ? hu->alignment : 1;
 161
 162         /* Check for error from previous call */
 163         if (IS_ERR(skb))
 164                 skb = NULL;
 165
 166         while (count) {
 167                 int i, len;
 168
 169                 /* remove padding bytes from buffer */
 170                 for (; hu->padding && count > 0; hu->padding--) {
 171                         count--;
 172                         buffer++;
 173                 }
 174                 if (!count)
 175                         break;
 176
 177                 if (!skb) {
 178                         for (i = 0; i < pkts_count; i++) {
 179                                 if (buffer[0] != (&pkts[i])->type)
 180                                         continue;
 181
 182                                 skb = bt_skb_alloc((&pkts[i])->maxlen,
 183                                                    GFP_ATOMIC);
 184                                 if (!skb)
 185                                         return ERR_PTR(-ENOMEM);
 186
 187                                 hci_skb_pkt_type(skb) = (&pkts[i])->type;
 188                                 hci_skb_expect(skb) = (&pkts[i])->hlen;
 189                                 break;
 190                         }
 191
 192                         /* Check for invalid packet type */
 193                         if (!skb)
 194                                 return ERR_PTR(-EILSEQ);
 195
 196                         count -= 1;
 197                         buffer += 1;
 198                 }
 199
 200                 len = min_t(uint, hci_skb_expect(skb) - skb->len, count);
 201                 skb_put_data(skb, buffer, len);
 202
 203                 count -= len;
 204                 buffer += len;
 205
 206                 /* Check for partial packet */
 207                 if (skb->len < hci_skb_expect(skb))
 208                         continue;
 209
 210                 for (i = 0; i < pkts_count; i++) {
 211                         if (hci_skb_pkt_type(skb) == (&pkts[i])->type)
 212                                 break;
 213                 }
 214
 215                 if (i >= pkts_count) {
 216                         kfree_skb(skb);
 217                         return ERR_PTR(-EILSEQ);
 218                 }
 219
 220                 if (skb->len == (&pkts[i])->hlen) {
 221                         u16 dlen;
 222
 223                         switch ((&pkts[i])->lsize) {
 224                         case 0:
 225                                 /* No variable data length */
 226                                 dlen = 0;
 227                                 break;
 228                         case 1:
 229                                 /* Single octet variable length */
 230                                 dlen = skb->data[(&pkts[i])->loff];
 231                                 hci_skb_expect(skb) += dlen;
 232
 233                                 if (skb_tailroom(skb) < dlen) {
 234                                         kfree_skb(skb);
 235                                         return ERR_PTR(-EMSGSIZE);
 236                                 }
 237                                 break;
 238                         case 2:
 239                                 /* Double octet variable length */
 240                                 dlen = get_unaligned_le16(skb->data +
 241                                                           (&pkts[i])->loff);
 242                                 hci_skb_expect(skb) += dlen;
 243
 244                                 if (skb_tailroom(skb) < dlen) {
 245                                         kfree_skb(skb);
 246                                         return ERR_PTR(-EMSGSIZE);
 247                                 }
 248                                 break;
 249                         default:
 250                                 /* Unsupported variable length */
 251                                 kfree_skb(skb);
 252                                 return ERR_PTR(-EILSEQ);
 253                         }
 254
 255                         if (!dlen) {
 256                                 hu->padding = (skb->len - 1) % alignment;
 257                                 hu->padding = (alignment - hu->padding) % alignment;
 258
 259                                 /* No more data, complete frame */
 260                                 (&pkts[i])->recv(hdev, skb);
 261                                 skb = NULL;
 262                         }
 263                 } else {
 264                         hu->padding = (skb->len - 1) % alignment;
 265                         hu->padding = (alignment - hu->padding) % alignment;
 266
 267                         /* Complete frame */
 268                         (&pkts[i])->recv(hdev, skb);
 269                         skb = NULL;
 270                 }
 271         }
 272
 273         return skb;
 274 }
 275 EXPORT_SYMBOL_GPL(h4_recv_buf);