1 /* att_internal.h - Attribute protocol handling */
2 
3 #include <zephyr/bluetooth/l2cap.h>
4 
5 /*
6  * Copyright (c) 2015-2016 Intel Corporation
7  *
8  * SPDX-License-Identifier: Apache-2.0
9  */
10 
11 #define BT_EATT_PSM		0x27
12 #define BT_ATT_DEFAULT_LE_MTU	23
13 #define BT_ATT_TIMEOUT		K_SECONDS(30)
14 
15 /* Local ATT Rx MTU
16  *
17  * This is the local 'Client Rx MTU'/'Server Rx MTU'. Core v5.3 Vol 3 Part F
18  * 3.4.2.2 requires that they are equal.
19  *
20  * The local ATT Server Rx MTU is limited to BT_L2CAP_TX_MTU because the GATT
21  * long attribute read protocol (Core v5.3 Vol 3 Part G 4.8.3) treats the ATT
22  * MTU as a promise about the read size. This requires the server to negotiate
23  * the ATT_MTU down to what it is actually able to send. This will unfortunately
24  * also limit how much the client is allowed to send.
25  */
26 #define BT_LOCAL_ATT_MTU_EATT MIN(BT_L2CAP_SDU_RX_MTU, BT_L2CAP_SDU_TX_MTU)
27 #define BT_LOCAL_ATT_MTU_UATT MIN(BT_L2CAP_RX_MTU, BT_L2CAP_TX_MTU)
28 
29 #define BT_ATT_BUF_SIZE MAX(BT_LOCAL_ATT_MTU_UATT, BT_LOCAL_ATT_MTU_EATT)
30 
31 struct bt_att_hdr {
32 	uint8_t  code;
33 } __packed;
34 
35 #define BT_ATT_OP_ERROR_RSP			0x01
36 struct bt_att_error_rsp {
37 	uint8_t  request;
38 	uint16_t handle;
39 	uint8_t  error;
40 } __packed;
41 
42 #define BT_ATT_OP_MTU_REQ			0x02
43 struct bt_att_exchange_mtu_req {
44 	uint16_t mtu;
45 } __packed;
46 
47 #define BT_ATT_OP_MTU_RSP			0x03
48 struct bt_att_exchange_mtu_rsp {
49 	uint16_t mtu;
50 } __packed;
51 
52 /* Find Information Request */
53 #define BT_ATT_OP_FIND_INFO_REQ			0x04
54 struct bt_att_find_info_req {
55 	uint16_t start_handle;
56 	uint16_t end_handle;
57 } __packed;
58 
59 /* Format field values for BT_ATT_OP_FIND_INFO_RSP */
60 #define BT_ATT_INFO_16				0x01
61 #define BT_ATT_INFO_128				0x02
62 
63 struct bt_att_info_16 {
64 	uint16_t handle;
65 	uint16_t uuid;
66 } __packed;
67 
68 struct bt_att_info_128 {
69 	uint16_t handle;
70 	uint8_t  uuid[16];
71 } __packed;
72 
73 /* Find Information Response */
74 #define BT_ATT_OP_FIND_INFO_RSP			0x05
75 struct bt_att_find_info_rsp {
76 	uint8_t  format;
77 	uint8_t  info[0];
78 } __packed;
79 
80 /* Find By Type Value Request */
81 #define BT_ATT_OP_FIND_TYPE_REQ			0x06
82 struct bt_att_find_type_req {
83 	uint16_t start_handle;
84 	uint16_t end_handle;
85 	uint16_t type;
86 	uint8_t  value[0];
87 } __packed;
88 
89 struct bt_att_handle_group {
90 	uint16_t start_handle;
91 	uint16_t end_handle;
92 } __packed;
93 
94 /* Find By Type Value Response */
95 #define BT_ATT_OP_FIND_TYPE_RSP			0x07
96 struct bt_att_find_type_rsp {
97 	struct bt_att_handle_group list[0];
98 } __packed;
99 
100 /* Read By Type Request */
101 #define BT_ATT_OP_READ_TYPE_REQ			0x08
102 struct bt_att_read_type_req {
103 	uint16_t start_handle;
104 	uint16_t end_handle;
105 	uint8_t  uuid[0];
106 } __packed;
107 
108 struct bt_att_data {
109 	uint16_t handle;
110 	uint8_t  value[0];
111 } __packed;
112 
113 /* Read By Type Response */
114 #define BT_ATT_OP_READ_TYPE_RSP			0x09
115 struct bt_att_read_type_rsp {
116 	uint8_t  len;
117 	struct bt_att_data data[0];
118 } __packed;
119 
120 /* Read Request */
121 #define BT_ATT_OP_READ_REQ			0x0a
122 struct bt_att_read_req {
123 	uint16_t handle;
124 } __packed;
125 
126 /* Read Response */
127 #define BT_ATT_OP_READ_RSP			0x0b
128 struct bt_att_read_rsp {
129 	uint8_t  value[0];
130 } __packed;
131 
132 /* Read Blob Request */
133 #define BT_ATT_OP_READ_BLOB_REQ			0x0c
134 struct bt_att_read_blob_req {
135 	uint16_t handle;
136 	uint16_t offset;
137 } __packed;
138 
139 /* Read Blob Response */
140 #define BT_ATT_OP_READ_BLOB_RSP			0x0d
141 struct bt_att_read_blob_rsp {
142 	uint8_t  value[0];
143 } __packed;
144 
145 /* Read Multiple Request */
146 #define BT_ATT_READ_MULT_MIN_LEN_REQ		0x04
147 
148 #define BT_ATT_OP_READ_MULT_REQ			0x0e
149 struct bt_att_read_mult_req {
150 	uint16_t handles[0];
151 } __packed;
152 
153 /* Read Multiple Response */
154 #define BT_ATT_OP_READ_MULT_RSP			0x0f
155 struct bt_att_read_mult_rsp {
156 	uint8_t  value[0];
157 } __packed;
158 
159 /* Read by Group Type Request */
160 #define BT_ATT_OP_READ_GROUP_REQ		0x10
161 struct bt_att_read_group_req {
162 	uint16_t start_handle;
163 	uint16_t end_handle;
164 	uint8_t  uuid[0];
165 } __packed;
166 
167 struct bt_att_group_data {
168 	uint16_t start_handle;
169 	uint16_t end_handle;
170 	uint8_t  value[0];
171 } __packed;
172 
173 /* Read by Group Type Response */
174 #define BT_ATT_OP_READ_GROUP_RSP		0x11
175 struct bt_att_read_group_rsp {
176 	uint8_t  len;
177 	struct bt_att_group_data data[0];
178 } __packed;
179 
180 /* Write Request */
181 #define BT_ATT_OP_WRITE_REQ			0x12
182 struct bt_att_write_req {
183 	uint16_t handle;
184 	uint8_t  value[0];
185 } __packed;
186 
187 /* Write Response */
188 #define BT_ATT_OP_WRITE_RSP			0x13
189 
190 /* Prepare Write Request */
191 #define BT_ATT_OP_PREPARE_WRITE_REQ		0x16
192 struct bt_att_prepare_write_req {
193 	uint16_t handle;
194 	uint16_t offset;
195 	uint8_t  value[0];
196 } __packed;
197 
198 /* Prepare Write Respond */
199 #define BT_ATT_OP_PREPARE_WRITE_RSP		0x17
200 struct bt_att_prepare_write_rsp {
201 	uint16_t handle;
202 	uint16_t offset;
203 	uint8_t  value[0];
204 } __packed;
205 
206 /* Execute Write Request */
207 #define BT_ATT_FLAG_CANCEL			0x00
208 #define BT_ATT_FLAG_EXEC			0x01
209 
210 #define BT_ATT_OP_EXEC_WRITE_REQ		0x18
211 struct bt_att_exec_write_req {
212 	uint8_t  flags;
213 } __packed;
214 
215 /* Execute Write Response */
216 #define BT_ATT_OP_EXEC_WRITE_RSP		0x19
217 
218 /* Handle Value Notification */
219 #define BT_ATT_OP_NOTIFY			0x1b
220 struct bt_att_notify {
221 	uint16_t handle;
222 	uint8_t  value[0];
223 } __packed;
224 
225 /* Handle Value Indication */
226 #define BT_ATT_OP_INDICATE			0x1d
227 struct bt_att_indicate {
228 	uint16_t handle;
229 	uint8_t  value[0];
230 } __packed;
231 
232 /* Handle Value Confirm */
233 #define BT_ATT_OP_CONFIRM			0x1e
234 
235 struct bt_att_signature {
236 	uint8_t  value[12];
237 } __packed;
238 
239 #define BT_ATT_OP_READ_MULT_VL_REQ		0x20
240 struct bt_att_read_mult_vl_req {
241 	uint16_t handles[0];
242 } __packed;
243 
244 /* Read Multiple Response */
245 #define BT_ATT_OP_READ_MULT_VL_RSP		0x21
246 struct bt_att_read_mult_vl_rsp {
247 	uint16_t len;
248 	uint8_t  value[0];
249 } __packed;
250 
251 /* Handle Multiple Value Notification */
252 #define BT_ATT_OP_NOTIFY_MULT			0x23
253 struct bt_att_notify_mult {
254 	uint16_t handle;
255 	uint16_t len;
256 	uint8_t  value[0];
257 } __packed;
258 
259 /* Write Command */
260 #define BT_ATT_OP_WRITE_CMD			0x52
261 struct bt_att_write_cmd {
262 	uint16_t handle;
263 	uint8_t  value[0];
264 } __packed;
265 
266 /* Signed Write Command */
267 #define BT_ATT_OP_SIGNED_WRITE_CMD		0xd2
268 struct bt_att_signed_write_cmd {
269 	uint16_t handle;
270 	uint8_t  value[0];
271 } __packed;
272 
273 typedef void (*bt_att_func_t)(struct bt_conn *conn, uint8_t err,
274 			      const void *pdu, uint16_t length,
275 			      void *user_data);
276 
277 typedef int (*bt_att_encode_t)(struct net_buf *buf, size_t len,
278 			       void *user_data);
279 
280 /* ATT request context */
281 struct bt_att_req {
282 	sys_snode_t node;
283 	bt_att_func_t func;
284 	struct net_buf *buf;
285 #if defined(CONFIG_BT_SMP)
286 	bt_att_encode_t encode;
287 	uint8_t retrying : 1;
288 	uint8_t att_op;
289 	size_t len;
290 #endif /* CONFIG_BT_SMP */
291 	void *user_data;
292 };
293 
294 void att_sent(struct bt_conn *conn, void *user_data);
295 
296 void bt_att_init(void);
297 uint16_t bt_att_get_mtu(struct bt_conn *conn);
298 struct net_buf *bt_att_create_pdu(struct bt_conn *conn, uint8_t op,
299 				  size_t len);
300 
301 /* Allocate a new request */
302 struct bt_att_req *bt_att_req_alloc(k_timeout_t timeout);
303 
304 /* Free a request */
305 void bt_att_req_free(struct bt_att_req *req);
306 
307 /* Send ATT PDU over a connection */
308 int bt_att_send(struct bt_conn *conn, struct net_buf *buf);
309 
310 /* Send ATT Request over a connection */
311 int bt_att_req_send(struct bt_conn *conn, struct bt_att_req *req);
312 
313 /* Cancel ATT request */
314 void bt_att_req_cancel(struct bt_conn *conn, struct bt_att_req *req);
315 
316 /* Disconnect EATT channels */
317 int bt_eatt_disconnect(struct bt_conn *conn);
318 
319 /** @brief Find a pending ATT request by its user_data pointer.
320  *  @param conn The connection the request was issued on.
321  *  @param user_data The pointer value to look for.
322  *  @return The found request. NULL if not found.
323  */
324 struct bt_att_req *bt_att_find_req_by_user_data(struct bt_conn *conn, const void *user_data);
325 
326 /* Checks if only the fixed ATT channel is connected */
327 bool bt_att_fixed_chan_only(struct bt_conn *conn);
328 
329 /* Clear the out of sync flag on all channels */
330 void bt_att_clear_out_of_sync_sent(struct bt_conn *conn);
331 
332 /* Check if BT_ATT_ERR_DB_OUT_OF_SYNC has been sent on the fixed ATT channel */
333 bool bt_att_out_of_sync_sent_on_fixed(struct bt_conn *conn);
334 
335 typedef void (*bt_gatt_complete_func_t) (struct bt_conn *conn, void *user_data);
336 void bt_att_set_tx_meta_data(struct net_buf *buf, bt_gatt_complete_func_t func, void *user_data,
337 			     enum bt_att_chan_opt chan_opt);
338 void bt_att_increment_tx_meta_data_attr_count(struct net_buf *buf, uint16_t attr_count);
339 
340 bool bt_att_tx_meta_data_match(const struct net_buf *buf, bt_gatt_complete_func_t func,
341 			       const void *user_data, enum bt_att_chan_opt chan_opt);
342 
343 void bt_att_free_tx_meta_data(const struct net_buf *buf);
344 
345 #if defined(CONFIG_BT_EATT)
346 #define BT_ATT_CHAN_OPT(_params) (_params)->chan_opt
347 #else
348 #define BT_ATT_CHAN_OPT(_params) BT_ATT_CHAN_OPT_UNENHANCED_ONLY
349 #endif /* CONFIG_BT_EATT */
350 
351 bool bt_att_chan_opt_valid(struct bt_conn *conn, enum bt_att_chan_opt chan_opt);
352