drivers/bluetooth/h4_recv.h

   1 /*
   2  *
   3  *  Generic Bluetooth HCI UART driver
   4  *
   5  *  Copyright (C) 2015-2018  Intel Corporation
   6  *
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License as published by
  10  *  the Free Software Foundation; either version 2 of the License, or
  11  *  (at your option) any later version.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License
  19  *  along with this program; if not, write to the Free Software
  20  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  *
  22  */
  23
  24 #include <asm/unaligned.h>
  25
  26 struct h4_recv_pkt {
  27         u8  type;       /* Packet type */
  28         u8  hlen;       /* Header length */
  29         u8  loff;       /* Data length offset in header */
  30         u8  lsize;      /* Data length field size */
  31         u16 maxlen;     /* Max overall packet length */
  32         int (*recv)(struct hci_dev *hdev, struct sk_buff *skb);
  33 };
  34
  35 #define H4_RECV_ACL \
  36         .type = HCI_ACLDATA_PKT, \
  37         .hlen = HCI_ACL_HDR_SIZE, \
  38         .loff = 2, \
  39         .lsize = 2, \
  40         .maxlen = HCI_MAX_FRAME_SIZE \
  41
  42 #define H4_RECV_SCO \
  43         .type = HCI_SCODATA_PKT, \
  44         .hlen = HCI_SCO_HDR_SIZE, \
  45         .loff = 2, \
  46         .lsize = 1, \
  47         .maxlen = HCI_MAX_SCO_SIZE
  48
  49 #define H4_RECV_EVENT \
  50         .type = HCI_EVENT_PKT, \
  51         .hlen = HCI_EVENT_HDR_SIZE, \
  52         .loff = 1, \
  53         .lsize = 1, \
  54         .maxlen = HCI_MAX_EVENT_SIZE
  55
  56 static inline struct sk_buff *h4_recv_buf(struct hci_dev *hdev,
  57                                           struct sk_buff *skb,
  58                                           const unsigned char *buffer,
  59                                           int count,
  60                                           const struct h4_recv_pkt *pkts,
  61                                           int pkts_count)
  62 {
  63         /* Check for error from previous call */
  64         if (IS_ERR(skb))
  65                 skb = NULL;
  66
  67         while (count) {
  68                 int i, len;
  69
  70                 if (!skb) {
  71                         for (i = 0; i < pkts_count; i++) {
  72                                 if (buffer[0] != (&pkts[i])->type)
  73                                         continue;
  74
  75                                 skb = bt_skb_alloc((&pkts[i])->maxlen,
  76                                                    GFP_ATOMIC);
  77                                 if (!skb)
  78                                         return ERR_PTR(-ENOMEM);
  79
  80                                 hci_skb_pkt_type(skb) = (&pkts[i])->type;
  81                                 hci_skb_expect(skb) = (&pkts[i])->hlen;
  82                                 break;
  83                         }
  84
  85                         /* Check for invalid packet type */
  86                         if (!skb)
  87                                 return ERR_PTR(-EILSEQ);
  88
  89                         count -= 1;
  90                         buffer += 1;
  91                 }
  92
  93                 len = min_t(uint, hci_skb_expect(skb) - skb->len, count);
  94                 skb_put_data(skb, buffer, len);
  95
  96                 count -= len;
  97                 buffer += len;
  98
  99                 /* Check for partial packet */
 100                 if (skb->len < hci_skb_expect(skb))
 101                         continue;
 102
 103                 for (i = 0; i < pkts_count; i++) {
 104                         if (hci_skb_pkt_type(skb) == (&pkts[i])->type)
 105                                 break;
 106                 }
 107
 108                 if (i >= pkts_count) {
 109                         kfree_skb(skb);
 110                         return ERR_PTR(-EILSEQ);
 111                 }
 112
 113                 if (skb->len == (&pkts[i])->hlen) {
 114                         u16 dlen;
 115
 116                         switch ((&pkts[i])->lsize) {
 117                         case 0:
 118                                 /* No variable data length */
 119                                 dlen = 0;
 120                                 break;
 121                         case 1:
 122                                 /* Single octet variable length */
 123                                 dlen = skb->data[(&pkts[i])->loff];
 124                                 hci_skb_expect(skb) += dlen;
 125
 126                                 if (skb_tailroom(skb) < dlen) {
 127                                         kfree_skb(skb);
 128                                         return ERR_PTR(-EMSGSIZE);
 129                                 }
 130                                 break;
 131                         case 2:
 132                                 /* Double octet variable length */
 133                                 dlen = get_unaligned_le16(skb->data +
 134                                                           (&pkts[i])->loff);
 135                                 hci_skb_expect(skb) += dlen;
 136
 137                                 if (skb_tailroom(skb) < dlen) {
 138                                         kfree_skb(skb);
 139                                         return ERR_PTR(-EMSGSIZE);
 140                                 }
 141                                 break;
 142                         default:
 143                                 /* Unsupported variable length */
 144                                 kfree_skb(skb);
 145                                 return ERR_PTR(-EILSEQ);
 146                         }
 147
 148                         if (!dlen) {
 149                                 /* No more data, complete frame */
 150                                 (&pkts[i])->recv(hdev, skb);
 151                                 skb = NULL;
 152                         }
 153                 } else {
 154                         /* Complete frame */
 155                         (&pkts[i])->recv(hdev, skb);
 156                         skb = NULL;
 157                 }
 158         }
 159
 160         return skb;
 161 }