net/bluetooth/msft.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2020 Google Corporation
   4  */
   5
   6 #include <net/bluetooth/bluetooth.h>
   7 #include <net/bluetooth/hci_core.h>
   8
   9 #include "msft.h"
  10
  11 #define MSFT_OP_READ_SUPPORTED_FEATURES         0x00
  12 struct msft_cp_read_supported_features {
  13         __u8   sub_opcode;
  14 } __packed;
  15
  16 struct msft_rp_read_supported_features {
  17         __u8   status;
  18         __u8   sub_opcode;
  19         __le64 features;
  20         __u8   evt_prefix_len;
  21         __u8   evt_prefix[];
  22 } __packed;
  23
  24 struct msft_data {
  25         __u64 features;
  26         __u8  evt_prefix_len;
  27         __u8  *evt_prefix;
  28 };
  29
  30 static bool read_supported_features(struct hci_dev *hdev,
  31                                     struct msft_data *msft)
  32 {
  33         struct msft_cp_read_supported_features cp;
  34         struct msft_rp_read_supported_features *rp;
  35         struct sk_buff *skb;
  36
  37         cp.sub_opcode = MSFT_OP_READ_SUPPORTED_FEATURES;
  38
  39         skb = __hci_cmd_sync(hdev, hdev->msft_opcode, sizeof(cp), &cp,
  40                              HCI_CMD_TIMEOUT);
  41         if (IS_ERR(skb)) {
  42                 bt_dev_err(hdev, "Failed to read MSFT supported features (%ld)",
  43                            PTR_ERR(skb));
  44                 return false;
  45         }
  46
  47         if (skb->len < sizeof(*rp)) {
  48                 bt_dev_err(hdev, "MSFT supported features length mismatch");
  49                 goto failed;
  50         }
  51
  52         rp = (struct msft_rp_read_supported_features *)skb->data;
  53
  54         if (rp->sub_opcode != MSFT_OP_READ_SUPPORTED_FEATURES)
  55                 goto failed;
  56
  57         if (rp->evt_prefix_len > 0) {
  58                 msft->evt_prefix = kmemdup(rp->evt_prefix, rp->evt_prefix_len,
  59                                            GFP_KERNEL);
  60                 if (!msft->evt_prefix)
  61                         goto failed;
  62         }
  63
  64         msft->evt_prefix_len = rp->evt_prefix_len;
  65         msft->features = __le64_to_cpu(rp->features);
  66
  67         kfree_skb(skb);
  68         return true;
  69
  70 failed:
  71         kfree_skb(skb);
  72         return false;
  73 }
  74
  75 void msft_do_open(struct hci_dev *hdev)
  76 {
  77         struct msft_data *msft;
  78
  79         if (hdev->msft_opcode == HCI_OP_NOP)
  80                 return;
  81
  82         bt_dev_dbg(hdev, "Initialize MSFT extension");
  83
  84         msft = kzalloc(sizeof(*msft), GFP_KERNEL);
  85         if (!msft)
  86                 return;
  87
  88         if (!read_supported_features(hdev, msft)) {
  89                 kfree(msft);
  90                 return;
  91         }
  92
  93         hdev->msft_data = msft;
  94 }
  95
  96 void msft_do_close(struct hci_dev *hdev)
  97 {
  98         struct msft_data *msft = hdev->msft_data;
  99
 100         if (!msft)
 101                 return;
 102
 103         bt_dev_dbg(hdev, "Cleanup of MSFT extension");
 104
 105         hdev->msft_data = NULL;
 106
 107         kfree(msft->evt_prefix);
 108         kfree(msft);
 109 }
 110
 111 void msft_vendor_evt(struct hci_dev *hdev, struct sk_buff *skb)
 112 {
 113         struct msft_data *msft = hdev->msft_data;
 114         u8 event;
 115
 116         if (!msft)
 117                 return;
 118
 119         /* When the extension has defined an event prefix, check that it
 120          * matches, and otherwise just return.
 121          */
 122         if (msft->evt_prefix_len > 0) {
 123                 if (skb->len < msft->evt_prefix_len)
 124                         return;
 125
 126                 if (memcmp(skb->data, msft->evt_prefix, msft->evt_prefix_len))
 127                         return;
 128
 129                 skb_pull(skb, msft->evt_prefix_len);
 130         }
 131
 132         /* Every event starts at least with an event code and the rest of
 133          * the data is variable and depends on the event code.
 134          */
 135         if (skb->len < 1)
 136                 return;
 137
 138         event = *skb->data;
 139         skb_pull(skb, 1);
 140
 141         bt_dev_dbg(hdev, "MSFT vendor event %u", event);
 142 }
 143
 144 __u64 msft_get_features(struct hci_dev *hdev)
 145 {
 146         struct msft_data *msft = hdev->msft_data;
 147
 148         return  msft ? msft->features : 0;
 149 }