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 (!count)
  71                         break;
  72
  73                 if (!skb) {
  74                         for (i = 0; i < pkts_count; i++) {
  75                                 if (buffer[0] != (&pkts[i])->type)
  76                                         continue;
  77
  78                                 skb = bt_skb_alloc((&pkts[i])->maxlen,
  79                                                    GFP_ATOMIC);
  80                                 if (!skb)
  81                                         return ERR_PTR(-ENOMEM);
  82
  83                                 hci_skb_pkt_type(skb) = (&pkts[i])->type;
  84                                 hci_skb_expect(skb) = (&pkts[i])->hlen;
  85                                 break;
  86                         }
  87
  88                         /* Check for invalid packet type */
  89                         if (!skb)
  90                                 return ERR_PTR(-EILSEQ);
  91
  92                         count -= 1;
  93                         buffer += 1;
  94                 }
  95
  96                 len = min_t(uint, hci_skb_expect(skb) - skb->len, count);
  97                 skb_put_data(skb, buffer, len);
  98
  99                 count -= len;
 100                 buffer += len;
 101
 102                 /* Check for partial packet */
 103                 if (skb->len < hci_skb_expect(skb))
 104                         continue;
 105
 106                 for (i = 0; i < pkts_count; i++) {
 107                         if (hci_skb_pkt_type(skb) == (&pkts[i])->type)
 108                                 break;
 109                 }
 110
 111                 if (i >= pkts_count) {
 112                         kfree_skb(skb);
 113                         return ERR_PTR(-EILSEQ);
 114                 }
 115
 116                 if (skb->len == (&pkts[i])->hlen) {
 117                         u16 dlen;
 118
 119                         switch ((&pkts[i])->lsize) {
 120                         case 0:
 121                                 /* No variable data length */
 122                                 dlen = 0;
 123                                 break;
 124                         case 1:
 125                                 /* Single octet variable length */
 126                                 dlen = skb->data[(&pkts[i])->loff];
 127                                 hci_skb_expect(skb) += dlen;
 128
 129                                 if (skb_tailroom(skb) < dlen) {
 130                                         kfree_skb(skb);
 131                                         return ERR_PTR(-EMSGSIZE);
 132                                 }
 133                                 break;
 134                         case 2:
 135                                 /* Double octet variable length */
 136                                 dlen = get_unaligned_le16(skb->data +
 137                                                           (&pkts[i])->loff);
 138                                 hci_skb_expect(skb) += dlen;
 139
 140                                 if (skb_tailroom(skb) < dlen) {
 141                                         kfree_skb(skb);
 142                                         return ERR_PTR(-EMSGSIZE);
 143                                 }
 144                                 break;
 145                         default:
 146                                 /* Unsupported variable length */
 147                                 kfree_skb(skb);
 148                                 return ERR_PTR(-EILSEQ);
 149                         }
 150
 151                         if (!dlen) {
 152                                 /* No more data, complete frame */
 153                                 (&pkts[i])->recv(hdev, skb);
 154                                 skb = NULL;
 155                         }
 156                 } else {
 157                         /* Complete frame */
 158                         (&pkts[i])->recv(hdev, skb);
 159                         skb = NULL;
 160                 }
 161         }
 162
 163         return skb;
 164 }