linux/drivers/bluetooth/hci_h4.c
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   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
  35struct h4_struct {
  36        struct sk_buff *rx_skb;
  37        struct sk_buff_head txq;
  38};
  39
  40/* Initialize protocol */
  41static 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 */
  58static 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 */
  70static 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) */
  87static 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
 100static 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 */
 108static 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
 127static 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
 133static 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
 144int __init h4_init(void)
 145{
 146        return hci_uart_register_proto(&h4p);
 147}
 148
 149int __exit h4_deinit(void)
 150{
 151        return hci_uart_unregister_proto(&h4p);
 152}
 153
 154struct 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}
 274EXPORT_SYMBOL_GPL(h4_recv_buf);
 275