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