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1 /******************************************************************************
2  *
3  *  Copyright (C) 1999-2012 Broadcom Corporation
4  *
5  *  Licensed under the Apache License, Version 2.0 (the "License");
6  *  you may not use this file except in compliance with the License.
7  *  You may obtain a copy of the License at:
8  *
9  *  http://www.apache.org/licenses/LICENSE-2.0
10  *
11  *  Unless required by applicable law or agreed to in writing, software
12  *  distributed under the License is distributed on an "AS IS" BASIS,
13  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  *  See the License for the specific language governing permissions and
15  *  limitations under the License.
16  *
17  ******************************************************************************/
18 
19 /******************************************************************************
20  *
21  *  This file contains the main L2CAP entry points
22  *
23  ******************************************************************************/
24 
25 #define LOG_TAG "bt_l2c_main"
26 
27 #include <stdio.h>
28 #include <stdlib.h>
29 #include <string.h>
30 
31 #include "bt_common.h"
32 #include "bt_target.h"
33 #include "btm_int.h"
34 #include "btu.h"
35 #include "device/include/controller.h"
36 #include "hcimsgs.h"
37 #include "l2c_api.h"
38 #include "l2c_int.h"
39 #include "l2cdefs.h"
40 #include "osi/include/log.h"
41 #include "osi/include/osi.h"
42 
43 extern fixed_queue_t* btu_general_alarm_queue;
44 
45 /******************************************************************************/
46 /*            L O C A L    F U N C T I O N     P R O T O T Y P E S            */
47 /******************************************************************************/
48 static void process_l2cap_cmd(tL2C_LCB* p_lcb, uint8_t* p, uint16_t pkt_len);
49 
50 /******************************************************************************/
51 /*               G L O B A L      L 2 C A P       D A T A                     */
52 /******************************************************************************/
53 tL2C_CB l2cb;
54 
55 /*******************************************************************************
56  *
57  * Function         l2c_rcv_acl_data
58  *
59  * Description      This function is called from the HCI Interface when an ACL
60  *                  data packet is received.
61  *
62  * Returns          void
63  *
64  ******************************************************************************/
l2c_rcv_acl_data(BT_HDR * p_msg)65 void l2c_rcv_acl_data(BT_HDR* p_msg) {
66   uint8_t* p = (uint8_t*)(p_msg + 1) + p_msg->offset;
67   uint16_t handle, hci_len;
68   uint8_t pkt_type;
69   tL2C_LCB* p_lcb;
70   tL2C_CCB* p_ccb = NULL;
71   uint16_t l2cap_len, rcv_cid, psm;
72   uint16_t credit;
73 
74   /* Extract the handle */
75   STREAM_TO_UINT16(handle, p);
76   pkt_type = HCID_GET_EVENT(handle);
77   handle = HCID_GET_HANDLE(handle);
78 
79   /* Since the HCI Transport is putting segmented packets back together, we */
80   /* should never get a valid packet with the type set to "continuation"    */
81   if (pkt_type != L2CAP_PKT_CONTINUE) {
82     /* Find the LCB based on the handle */
83     p_lcb = l2cu_find_lcb_by_handle(handle);
84     if (p_lcb == NULL) {
85       uint8_t cmd_code;
86 
87       /* There is a slight possibility (specifically with USB) that we get an */
88       /* L2CAP connection request before we get the HCI connection complete.  */
89       /* So for these types of messages, hold them for up to 2 seconds.       */
90       STREAM_TO_UINT16(hci_len, p);
91       STREAM_TO_UINT16(l2cap_len, p);
92       STREAM_TO_UINT16(rcv_cid, p);
93       STREAM_TO_UINT8(cmd_code, p);
94 
95       if ((p_msg->layer_specific == 0) && (rcv_cid == L2CAP_SIGNALLING_CID) &&
96           (cmd_code == L2CAP_CMD_INFO_REQ || cmd_code == L2CAP_CMD_CONN_REQ)) {
97         L2CAP_TRACE_WARNING(
98             "L2CAP - holding ACL for unknown handle:%d ls:%d"
99             "  cid:%d opcode:%d cur count:%d",
100             handle, p_msg->layer_specific, rcv_cid, cmd_code,
101             list_length(l2cb.rcv_pending_q));
102         p_msg->layer_specific = 2;
103         list_append(l2cb.rcv_pending_q, p_msg);
104 
105         if (list_length(l2cb.rcv_pending_q) == 1) {
106           alarm_set_on_queue(l2cb.receive_hold_timer, BT_1SEC_TIMEOUT_MS,
107                              l2c_receive_hold_timer_timeout, NULL,
108                              btu_general_alarm_queue);
109         }
110 
111         return;
112       } else {
113         L2CAP_TRACE_ERROR(
114             "L2CAP - rcvd ACL for unknown handle:%d ls:%d cid:%d"
115             " opcode:%d cur count:%d",
116             handle, p_msg->layer_specific, rcv_cid, cmd_code,
117             list_length(l2cb.rcv_pending_q));
118       }
119       osi_free(p_msg);
120       return;
121     }
122   } else {
123     L2CAP_TRACE_WARNING("L2CAP - expected pkt start or complete, got: %d",
124                         pkt_type);
125     osi_free(p_msg);
126     return;
127   }
128 
129   /* Extract the length and update the buffer header */
130   STREAM_TO_UINT16(hci_len, p);
131   p_msg->offset += 4;
132 
133   if (hci_len < L2CAP_PKT_OVERHEAD) {
134     /* Must receive at least the L2CAP length and CID */
135     L2CAP_TRACE_WARNING("L2CAP - got incorrect hci header");
136     osi_free(p_msg);
137     return;
138   }
139 
140   /* Extract the length and CID */
141   STREAM_TO_UINT16(l2cap_len, p);
142   STREAM_TO_UINT16(rcv_cid, p);
143 
144   /* for BLE channel, always notify connection when ACL data received on the
145    * link */
146   if (p_lcb && p_lcb->transport == BT_TRANSPORT_LE &&
147       p_lcb->link_state != LST_DISCONNECTING)
148     /* only process fixed channel data as channel open indication when link is
149      * not in disconnecting mode */
150     l2cble_notify_le_connection(p_lcb->remote_bd_addr);
151 
152   /* Find the CCB for this CID */
153   if (rcv_cid >= L2CAP_BASE_APPL_CID) {
154     p_ccb = l2cu_find_ccb_by_cid(p_lcb, rcv_cid);
155     if (p_ccb == NULL) {
156       L2CAP_TRACE_WARNING("L2CAP - unknown CID: 0x%04x", rcv_cid);
157       osi_free(p_msg);
158       return;
159     }
160   }
161 
162   p_msg->len = hci_len - L2CAP_PKT_OVERHEAD;
163   p_msg->offset += L2CAP_PKT_OVERHEAD;
164 
165   if (l2cap_len != p_msg->len) {
166     L2CAP_TRACE_WARNING("L2CAP - bad length in pkt. Exp: %d  Act: %d",
167                         l2cap_len, p_msg->len);
168 
169     osi_free(p_msg);
170     return;
171   }
172 
173   /* Send the data through the channel state machine */
174   if (rcv_cid == L2CAP_SIGNALLING_CID) {
175     process_l2cap_cmd(p_lcb, p, l2cap_len);
176     osi_free(p_msg);
177   } else if (rcv_cid == L2CAP_CONNECTIONLESS_CID) {
178     /* process_connectionless_data (p_lcb); */
179     STREAM_TO_UINT16(psm, p);
180     L2CAP_TRACE_DEBUG("GOT CONNECTIONLESS DATA PSM:%d", psm);
181 
182 #if (L2CAP_UCD_INCLUDED == TRUE)
183     /* if it is not broadcast, check UCD registration */
184     if (l2c_ucd_check_rx_pkts(p_lcb, p_msg)) {
185       /* nothing to do */
186     } else
187 #endif
188       osi_free(p_msg);
189   } else if (rcv_cid == L2CAP_BLE_SIGNALLING_CID) {
190     l2cble_process_sig_cmd(p_lcb, p, l2cap_len);
191     osi_free(p_msg);
192   }
193 #if (L2CAP_NUM_FIXED_CHNLS > 0)
194   else if ((rcv_cid >= L2CAP_FIRST_FIXED_CHNL) &&
195            (rcv_cid <= L2CAP_LAST_FIXED_CHNL) &&
196            (l2cb.fixed_reg[rcv_cid - L2CAP_FIRST_FIXED_CHNL]
197                 .pL2CA_FixedData_Cb != NULL)) {
198     /* If no CCB for this channel, allocate one */
199     if (p_lcb &&
200         /* only process fixed channel data when link is open or wait for data
201            indication */
202         (p_lcb->link_state != LST_DISCONNECTING) &&
203         l2cu_initialize_fixed_ccb(
204             p_lcb, rcv_cid, &l2cb.fixed_reg[rcv_cid - L2CAP_FIRST_FIXED_CHNL]
205                                  .fixed_chnl_opts)) {
206       p_ccb = p_lcb->p_fixed_ccbs[rcv_cid - L2CAP_FIRST_FIXED_CHNL];
207 
208       if (p_ccb->peer_cfg.fcr.mode != L2CAP_FCR_BASIC_MODE)
209         l2c_fcr_proc_pdu(p_ccb, p_msg);
210       else
211         (*l2cb.fixed_reg[rcv_cid - L2CAP_FIRST_FIXED_CHNL].pL2CA_FixedData_Cb)(
212             rcv_cid, p_lcb->remote_bd_addr, p_msg);
213     } else
214       osi_free(p_msg);
215   }
216 #endif
217 
218   else {
219     if (p_ccb == NULL)
220       osi_free(p_msg);
221     else {
222       if (p_lcb->transport == BT_TRANSPORT_LE) {
223         l2c_lcc_proc_pdu(p_ccb, p_msg);
224         // Got a pkt, valid send out credits to the peer device
225         credit = L2CAP_LE_DEFAULT_CREDIT;
226         l2c_csm_execute(p_ccb, L2CEVT_L2CA_SEND_FLOW_CONTROL_CREDIT, &credit);
227       } else {
228         /* Basic mode packets go straight to the state machine */
229         if (p_ccb->peer_cfg.fcr.mode == L2CAP_FCR_BASIC_MODE)
230           l2c_csm_execute(p_ccb, L2CEVT_L2CAP_DATA, p_msg);
231         else {
232           /* eRTM or streaming mode, so we need to validate states first */
233           if ((p_ccb->chnl_state == CST_OPEN) ||
234               (p_ccb->chnl_state == CST_CONFIG))
235             l2c_fcr_proc_pdu(p_ccb, p_msg);
236           else
237             osi_free(p_msg);
238         }
239       }
240     }
241   }
242 }
243 
244 /*******************************************************************************
245  *
246  * Function         process_l2cap_cmd
247  *
248  * Description      This function is called when a packet is received on the
249  *                  L2CAP signalling CID
250  *
251  * Returns          void
252  *
253  ******************************************************************************/
process_l2cap_cmd(tL2C_LCB * p_lcb,uint8_t * p,uint16_t pkt_len)254 static void process_l2cap_cmd(tL2C_LCB* p_lcb, uint8_t* p, uint16_t pkt_len) {
255   uint8_t *p_pkt_end, *p_next_cmd, *p_cfg_end, *p_cfg_start;
256   uint8_t cmd_code, cfg_code, cfg_len, id;
257   tL2C_CONN_INFO con_info;
258   tL2CAP_CFG_INFO cfg_info;
259   uint16_t rej_reason, rej_mtu, lcid, rcid, info_type;
260   tL2C_CCB* p_ccb;
261   tL2C_RCB* p_rcb;
262   bool cfg_rej, pkt_size_rej = false;
263   uint16_t cfg_rej_len, cmd_len;
264   uint16_t result;
265   tL2C_CONN_INFO ci;
266 
267   /* if l2cap command received in CID 1 on top of an LE link, ignore this
268    * command */
269   if (p_lcb->transport == BT_TRANSPORT_LE) return;
270 
271   /* Reject the packet if it exceeds the default Signalling Channel MTU */
272   if (pkt_len > L2CAP_DEFAULT_MTU) {
273     /* Core Spec requires a single response to the first command found in a
274     *multi-command
275     ** L2cap packet.  If only responses in the packet, then it will be ignored.
276     ** Here we simply mark the bad packet and decide which cmd ID to reject
277     *later
278     */
279     pkt_size_rej = true;
280     L2CAP_TRACE_ERROR("L2CAP SIG MTU Pkt Len Exceeded (672) -> pkt_len: %d",
281                       pkt_len);
282   }
283 
284   p_next_cmd = p;
285   p_pkt_end = p + pkt_len;
286 
287   memset(&cfg_info, 0, sizeof(cfg_info));
288 
289   /* An L2CAP packet may contain multiple commands */
290   while (true) {
291     /* Smallest command is 4 bytes */
292     p = p_next_cmd;
293     if (p > (p_pkt_end - 4)) break;
294 
295     STREAM_TO_UINT8(cmd_code, p);
296     STREAM_TO_UINT8(id, p);
297     STREAM_TO_UINT16(cmd_len, p);
298 
299     if (cmd_len > BT_SMALL_BUFFER_SIZE) {
300       L2CAP_TRACE_WARNING("L2CAP - Invalid MTU Size");
301       l2cu_send_peer_cmd_reject(p_lcb, L2CAP_CMD_REJ_MTU_EXCEEDED, id, 0, 0);
302       return;
303     }
304 
305     /* Check command length does not exceed packet length */
306     p_next_cmd = p + cmd_len;
307     if (p_next_cmd > p_pkt_end) {
308       L2CAP_TRACE_WARNING("Command len bad  pkt_len: %d  cmd_len: %d  code: %d",
309                           pkt_len, cmd_len, cmd_code);
310       break;
311     }
312 
313     L2CAP_TRACE_DEBUG("cmd_code: %d, id:%d, cmd_len:%d", cmd_code, id, cmd_len);
314 
315     /* Bad L2CAP packet length, look or cmd to reject */
316     if (pkt_size_rej) {
317       /* If command found rejected it and we're done, otherwise keep looking */
318       if (l2c_is_cmd_rejected(cmd_code, id, p_lcb))
319         return;
320       else
321         continue; /* Look for next cmd/response in current packet */
322     }
323 
324     switch (cmd_code) {
325       case L2CAP_CMD_REJECT:
326         STREAM_TO_UINT16(rej_reason, p);
327         if (rej_reason == L2CAP_CMD_REJ_MTU_EXCEEDED) {
328           STREAM_TO_UINT16(rej_mtu, p);
329           /* What to do with the MTU reject ? We have negotiated an MTU. For now
330            */
331           /* we will ignore it and let a higher protocol timeout take care of it
332            */
333 
334           L2CAP_TRACE_WARNING("L2CAP - MTU rej Handle: %d MTU: %d",
335                               p_lcb->handle, rej_mtu);
336         }
337         if (rej_reason == L2CAP_CMD_REJ_INVALID_CID) {
338           STREAM_TO_UINT16(rcid, p);
339           STREAM_TO_UINT16(lcid, p);
340 
341           L2CAP_TRACE_WARNING(
342               "L2CAP - rej with CID invalid, LCID: 0x%04x RCID: 0x%04x", lcid,
343               rcid);
344 
345           /* Remote CID invalid. Treat as a disconnect */
346           p_ccb = l2cu_find_ccb_by_cid(p_lcb, lcid);
347           if ((p_ccb != NULL) && (p_ccb->remote_cid == rcid)) {
348             /* Fake link disconnect - no reply is generated */
349             l2c_csm_execute(p_ccb, L2CEVT_LP_DISCONNECT_IND, NULL);
350           }
351         }
352 
353         /* SonyEricsson Info request Bug workaround (Continue connection) */
354         else if (rej_reason == L2CAP_CMD_REJ_NOT_UNDERSTOOD &&
355                  p_lcb->w4_info_rsp) {
356           alarm_cancel(p_lcb->info_resp_timer);
357 
358           p_lcb->w4_info_rsp = false;
359           ci.status = HCI_SUCCESS;
360           memcpy(ci.bd_addr, p_lcb->remote_bd_addr, sizeof(BD_ADDR));
361 
362           /* For all channels, send the event through their FSMs */
363           for (p_ccb = p_lcb->ccb_queue.p_first_ccb; p_ccb;
364                p_ccb = p_ccb->p_next_ccb) {
365             l2c_csm_execute(p_ccb, L2CEVT_L2CAP_INFO_RSP, &ci);
366           }
367         }
368         break;
369 
370       case L2CAP_CMD_CONN_REQ:
371         STREAM_TO_UINT16(con_info.psm, p);
372         STREAM_TO_UINT16(rcid, p);
373         p_rcb = l2cu_find_rcb_by_psm(con_info.psm);
374         if (p_rcb == NULL) {
375           L2CAP_TRACE_WARNING("L2CAP - rcvd conn req for unknown PSM: %d",
376                               con_info.psm);
377           l2cu_reject_connection(p_lcb, rcid, id, L2CAP_CONN_NO_PSM);
378           break;
379         } else {
380           if (!p_rcb->api.pL2CA_ConnectInd_Cb) {
381             L2CAP_TRACE_WARNING(
382                 "L2CAP - rcvd conn req for outgoing-only connection PSM: %d",
383                 con_info.psm);
384             l2cu_reject_connection(p_lcb, rcid, id, L2CAP_CONN_NO_PSM);
385             break;
386           }
387         }
388         p_ccb = l2cu_allocate_ccb(p_lcb, 0);
389         if (p_ccb == NULL) {
390           L2CAP_TRACE_ERROR("L2CAP - unable to allocate CCB");
391           l2cu_reject_connection(p_lcb, rcid, id, L2CAP_CONN_NO_RESOURCES);
392           break;
393         }
394         p_ccb->remote_id = id;
395         p_ccb->p_rcb = p_rcb;
396         p_ccb->remote_cid = rcid;
397 
398         l2c_csm_execute(p_ccb, L2CEVT_L2CAP_CONNECT_REQ, &con_info);
399         break;
400 
401       case L2CAP_CMD_CONN_RSP:
402         STREAM_TO_UINT16(con_info.remote_cid, p);
403         STREAM_TO_UINT16(lcid, p);
404         STREAM_TO_UINT16(con_info.l2cap_result, p);
405         STREAM_TO_UINT16(con_info.l2cap_status, p);
406 
407         p_ccb = l2cu_find_ccb_by_cid(p_lcb, lcid);
408         if (p_ccb == NULL) {
409           L2CAP_TRACE_WARNING("L2CAP - no CCB for conn rsp, LCID: %d RCID: %d",
410                               lcid, con_info.remote_cid);
411           break;
412         }
413         if (p_ccb->local_id != id) {
414           L2CAP_TRACE_WARNING("L2CAP - con rsp - bad ID. Exp: %d Got: %d",
415                               p_ccb->local_id, id);
416           break;
417         }
418 
419         if (con_info.l2cap_result == L2CAP_CONN_OK)
420           l2c_csm_execute(p_ccb, L2CEVT_L2CAP_CONNECT_RSP, &con_info);
421         else if (con_info.l2cap_result == L2CAP_CONN_PENDING)
422           l2c_csm_execute(p_ccb, L2CEVT_L2CAP_CONNECT_RSP_PND, &con_info);
423         else
424           l2c_csm_execute(p_ccb, L2CEVT_L2CAP_CONNECT_RSP_NEG, &con_info);
425 
426         break;
427 
428       case L2CAP_CMD_CONFIG_REQ:
429         p_cfg_end = p + cmd_len;
430         cfg_rej = false;
431         cfg_rej_len = 0;
432 
433         STREAM_TO_UINT16(lcid, p);
434         STREAM_TO_UINT16(cfg_info.flags, p);
435 
436         p_cfg_start = p;
437 
438         cfg_info.flush_to_present = cfg_info.mtu_present =
439             cfg_info.qos_present = cfg_info.fcr_present = cfg_info.fcs_present =
440                 false;
441 
442         while (p < p_cfg_end) {
443           STREAM_TO_UINT8(cfg_code, p);
444           STREAM_TO_UINT8(cfg_len, p);
445 
446           switch (cfg_code & 0x7F) {
447             case L2CAP_CFG_TYPE_MTU:
448               cfg_info.mtu_present = true;
449               STREAM_TO_UINT16(cfg_info.mtu, p);
450               break;
451 
452             case L2CAP_CFG_TYPE_FLUSH_TOUT:
453               cfg_info.flush_to_present = true;
454               STREAM_TO_UINT16(cfg_info.flush_to, p);
455               break;
456 
457             case L2CAP_CFG_TYPE_QOS:
458               cfg_info.qos_present = true;
459               STREAM_TO_UINT8(cfg_info.qos.qos_flags, p);
460               STREAM_TO_UINT8(cfg_info.qos.service_type, p);
461               STREAM_TO_UINT32(cfg_info.qos.token_rate, p);
462               STREAM_TO_UINT32(cfg_info.qos.token_bucket_size, p);
463               STREAM_TO_UINT32(cfg_info.qos.peak_bandwidth, p);
464               STREAM_TO_UINT32(cfg_info.qos.latency, p);
465               STREAM_TO_UINT32(cfg_info.qos.delay_variation, p);
466               break;
467 
468             case L2CAP_CFG_TYPE_FCR:
469               cfg_info.fcr_present = true;
470               STREAM_TO_UINT8(cfg_info.fcr.mode, p);
471               STREAM_TO_UINT8(cfg_info.fcr.tx_win_sz, p);
472               STREAM_TO_UINT8(cfg_info.fcr.max_transmit, p);
473               STREAM_TO_UINT16(cfg_info.fcr.rtrans_tout, p);
474               STREAM_TO_UINT16(cfg_info.fcr.mon_tout, p);
475               STREAM_TO_UINT16(cfg_info.fcr.mps, p);
476               break;
477 
478             case L2CAP_CFG_TYPE_FCS:
479               cfg_info.fcs_present = true;
480               STREAM_TO_UINT8(cfg_info.fcs, p);
481               break;
482 
483             case L2CAP_CFG_TYPE_EXT_FLOW:
484               cfg_info.ext_flow_spec_present = true;
485               STREAM_TO_UINT8(cfg_info.ext_flow_spec.id, p);
486               STREAM_TO_UINT8(cfg_info.ext_flow_spec.stype, p);
487               STREAM_TO_UINT16(cfg_info.ext_flow_spec.max_sdu_size, p);
488               STREAM_TO_UINT32(cfg_info.ext_flow_spec.sdu_inter_time, p);
489               STREAM_TO_UINT32(cfg_info.ext_flow_spec.access_latency, p);
490               STREAM_TO_UINT32(cfg_info.ext_flow_spec.flush_timeout, p);
491               break;
492 
493             default:
494               /* sanity check option length */
495               if ((cfg_len + L2CAP_CFG_OPTION_OVERHEAD) <= cmd_len) {
496                 p += cfg_len;
497                 if ((cfg_code & 0x80) == 0) {
498                   cfg_rej_len += cfg_len + L2CAP_CFG_OPTION_OVERHEAD;
499                   cfg_rej = true;
500                 }
501               }
502               /* bad length; force loop exit */
503               else {
504                 p = p_cfg_end;
505                 cfg_rej = true;
506               }
507               break;
508           }
509         }
510 
511         p_ccb = l2cu_find_ccb_by_cid(p_lcb, lcid);
512         if (p_ccb != NULL) {
513           p_ccb->remote_id = id;
514           if (cfg_rej) {
515             l2cu_send_peer_config_rej(
516                 p_ccb, p_cfg_start, (uint16_t)(cmd_len - L2CAP_CONFIG_REQ_LEN),
517                 cfg_rej_len);
518           } else {
519             l2c_csm_execute(p_ccb, L2CEVT_L2CAP_CONFIG_REQ, &cfg_info);
520           }
521         } else {
522           /* updated spec says send command reject on invalid cid */
523           l2cu_send_peer_cmd_reject(p_lcb, L2CAP_CMD_REJ_INVALID_CID, id, 0, 0);
524         }
525         break;
526 
527       case L2CAP_CMD_CONFIG_RSP:
528         p_cfg_end = p + cmd_len;
529         STREAM_TO_UINT16(lcid, p);
530         STREAM_TO_UINT16(cfg_info.flags, p);
531         STREAM_TO_UINT16(cfg_info.result, p);
532 
533         cfg_info.flush_to_present = cfg_info.mtu_present =
534             cfg_info.qos_present = cfg_info.fcr_present = cfg_info.fcs_present =
535                 false;
536 
537         while (p < p_cfg_end) {
538           STREAM_TO_UINT8(cfg_code, p);
539           STREAM_TO_UINT8(cfg_len, p);
540 
541           switch (cfg_code & 0x7F) {
542             case L2CAP_CFG_TYPE_MTU:
543               cfg_info.mtu_present = true;
544               STREAM_TO_UINT16(cfg_info.mtu, p);
545               break;
546 
547             case L2CAP_CFG_TYPE_FLUSH_TOUT:
548               cfg_info.flush_to_present = true;
549               STREAM_TO_UINT16(cfg_info.flush_to, p);
550               break;
551 
552             case L2CAP_CFG_TYPE_QOS:
553               cfg_info.qos_present = true;
554               STREAM_TO_UINT8(cfg_info.qos.qos_flags, p);
555               STREAM_TO_UINT8(cfg_info.qos.service_type, p);
556               STREAM_TO_UINT32(cfg_info.qos.token_rate, p);
557               STREAM_TO_UINT32(cfg_info.qos.token_bucket_size, p);
558               STREAM_TO_UINT32(cfg_info.qos.peak_bandwidth, p);
559               STREAM_TO_UINT32(cfg_info.qos.latency, p);
560               STREAM_TO_UINT32(cfg_info.qos.delay_variation, p);
561               break;
562 
563             case L2CAP_CFG_TYPE_FCR:
564               cfg_info.fcr_present = true;
565               STREAM_TO_UINT8(cfg_info.fcr.mode, p);
566               STREAM_TO_UINT8(cfg_info.fcr.tx_win_sz, p);
567               STREAM_TO_UINT8(cfg_info.fcr.max_transmit, p);
568               STREAM_TO_UINT16(cfg_info.fcr.rtrans_tout, p);
569               STREAM_TO_UINT16(cfg_info.fcr.mon_tout, p);
570               STREAM_TO_UINT16(cfg_info.fcr.mps, p);
571               break;
572 
573             case L2CAP_CFG_TYPE_FCS:
574               cfg_info.fcs_present = true;
575               STREAM_TO_UINT8(cfg_info.fcs, p);
576               break;
577 
578             case L2CAP_CFG_TYPE_EXT_FLOW:
579               cfg_info.ext_flow_spec_present = true;
580               STREAM_TO_UINT8(cfg_info.ext_flow_spec.id, p);
581               STREAM_TO_UINT8(cfg_info.ext_flow_spec.stype, p);
582               STREAM_TO_UINT16(cfg_info.ext_flow_spec.max_sdu_size, p);
583               STREAM_TO_UINT32(cfg_info.ext_flow_spec.sdu_inter_time, p);
584               STREAM_TO_UINT32(cfg_info.ext_flow_spec.access_latency, p);
585               STREAM_TO_UINT32(cfg_info.ext_flow_spec.flush_timeout, p);
586               break;
587           }
588         }
589 
590         p_ccb = l2cu_find_ccb_by_cid(p_lcb, lcid);
591         if (p_ccb != NULL) {
592           if (p_ccb->local_id != id) {
593             L2CAP_TRACE_WARNING("L2CAP - cfg rsp - bad ID. Exp: %d Got: %d",
594                                 p_ccb->local_id, id);
595             break;
596           }
597           if ((cfg_info.result == L2CAP_CFG_OK) ||
598               (cfg_info.result == L2CAP_CFG_PENDING))
599             l2c_csm_execute(p_ccb, L2CEVT_L2CAP_CONFIG_RSP, &cfg_info);
600           else
601             l2c_csm_execute(p_ccb, L2CEVT_L2CAP_CONFIG_RSP_NEG, &cfg_info);
602         } else {
603           L2CAP_TRACE_WARNING("L2CAP - rcvd cfg rsp for unknown CID: 0x%04x",
604                               lcid);
605         }
606         break;
607 
608       case L2CAP_CMD_DISC_REQ:
609         STREAM_TO_UINT16(lcid, p);
610         STREAM_TO_UINT16(rcid, p);
611 
612         p_ccb = l2cu_find_ccb_by_cid(p_lcb, lcid);
613         if (p_ccb != NULL) {
614           if (p_ccb->remote_cid == rcid) {
615             p_ccb->remote_id = id;
616             l2c_csm_execute(p_ccb, L2CEVT_L2CAP_DISCONNECT_REQ, &con_info);
617           }
618         } else
619           l2cu_send_peer_disc_rsp(p_lcb, id, lcid, rcid);
620 
621         break;
622 
623       case L2CAP_CMD_DISC_RSP:
624         STREAM_TO_UINT16(rcid, p);
625         STREAM_TO_UINT16(lcid, p);
626 
627         p_ccb = l2cu_find_ccb_by_cid(p_lcb, lcid);
628         if (p_ccb != NULL) {
629           if ((p_ccb->remote_cid == rcid) && (p_ccb->local_id == id)) {
630             l2c_csm_execute(p_ccb, L2CEVT_L2CAP_DISCONNECT_RSP, &con_info);
631           }
632         }
633         break;
634 
635       case L2CAP_CMD_ECHO_REQ:
636         l2cu_send_peer_echo_rsp(p_lcb, id, p, cmd_len);
637         break;
638 
639       case L2CAP_CMD_ECHO_RSP:
640         if (p_lcb->p_echo_rsp_cb) {
641           tL2CA_ECHO_RSP_CB* p_cb = p_lcb->p_echo_rsp_cb;
642 
643           /* Zero out the callback in case app immediately calls us again */
644           p_lcb->p_echo_rsp_cb = NULL;
645 
646           (*p_cb)(L2CAP_PING_RESULT_OK);
647         }
648         break;
649 
650       case L2CAP_CMD_INFO_REQ:
651         STREAM_TO_UINT16(info_type, p);
652         l2cu_send_peer_info_rsp(p_lcb, id, info_type);
653         break;
654 
655       case L2CAP_CMD_INFO_RSP:
656         /* Stop the link connect timer if sent before L2CAP connection is up */
657         if (p_lcb->w4_info_rsp) {
658           alarm_cancel(p_lcb->info_resp_timer);
659           p_lcb->w4_info_rsp = false;
660         }
661 
662         STREAM_TO_UINT16(info_type, p);
663         STREAM_TO_UINT16(result, p);
664 
665         p_lcb->info_rx_bits |= (1 << info_type);
666 
667         if ((info_type == L2CAP_EXTENDED_FEATURES_INFO_TYPE) &&
668             (result == L2CAP_INFO_RESP_RESULT_SUCCESS)) {
669           STREAM_TO_UINT32(p_lcb->peer_ext_fea, p);
670 
671 #if (L2CAP_NUM_FIXED_CHNLS > 0)
672           if (p_lcb->peer_ext_fea & L2CAP_EXTFEA_FIXED_CHNLS) {
673             l2cu_send_peer_info_req(p_lcb, L2CAP_FIXED_CHANNELS_INFO_TYPE);
674             break;
675           } else {
676             l2cu_process_fixed_chnl_resp(p_lcb);
677           }
678 #endif
679         }
680 
681 #if (L2CAP_NUM_FIXED_CHNLS > 0)
682         if (info_type == L2CAP_FIXED_CHANNELS_INFO_TYPE) {
683           if (result == L2CAP_INFO_RESP_RESULT_SUCCESS) {
684             memcpy(p_lcb->peer_chnl_mask, p, L2CAP_FIXED_CHNL_ARRAY_SIZE);
685           }
686 
687           l2cu_process_fixed_chnl_resp(p_lcb);
688         }
689 #endif
690 #if (L2CAP_UCD_INCLUDED == TRUE)
691         else if (info_type == L2CAP_CONNLESS_MTU_INFO_TYPE) {
692           if (result == L2CAP_INFO_RESP_RESULT_SUCCESS) {
693             STREAM_TO_UINT16(p_lcb->ucd_mtu, p);
694           }
695         }
696 #endif
697 
698         ci.status = HCI_SUCCESS;
699         memcpy(ci.bd_addr, p_lcb->remote_bd_addr, sizeof(BD_ADDR));
700         for (p_ccb = p_lcb->ccb_queue.p_first_ccb; p_ccb;
701              p_ccb = p_ccb->p_next_ccb) {
702           l2c_csm_execute(p_ccb, L2CEVT_L2CAP_INFO_RSP, &ci);
703         }
704         break;
705 
706       default:
707         L2CAP_TRACE_WARNING("L2CAP - bad cmd code: %d", cmd_code);
708         l2cu_send_peer_cmd_reject(p_lcb, L2CAP_CMD_REJ_NOT_UNDERSTOOD, id, 0,
709                                   0);
710         return;
711     }
712   }
713 }
714 
715 /*******************************************************************************
716  *
717  * Function         l2c_process_held_packets
718  *
719  * Description      This function processes any L2CAP packets that arrived
720  *                  before the HCI connection complete arrived. It is a work
721  *                  around for badly behaved controllers.
722  *
723  * Returns          void
724  *
725  ******************************************************************************/
l2c_process_held_packets(bool timed_out)726 void l2c_process_held_packets(bool timed_out) {
727   if (list_is_empty(l2cb.rcv_pending_q)) return;
728 
729   if (!timed_out) {
730     alarm_cancel(l2cb.receive_hold_timer);
731     L2CAP_TRACE_WARNING("L2CAP HOLD CONTINUE");
732   } else {
733     L2CAP_TRACE_WARNING("L2CAP HOLD TIMEOUT");
734   }
735 
736   for (const list_node_t* node = list_begin(l2cb.rcv_pending_q);
737        node != list_end(l2cb.rcv_pending_q);) {
738     BT_HDR* p_buf = static_cast<BT_HDR*>(list_node(node));
739     node = list_next(node);
740     if (!timed_out || (!p_buf->layer_specific) ||
741         (--p_buf->layer_specific == 0)) {
742       list_remove(l2cb.rcv_pending_q, p_buf);
743       p_buf->layer_specific = 0xFFFF;
744       l2c_rcv_acl_data(p_buf);
745     }
746   }
747 
748   /* If anyone still in the queue, restart the timeout */
749   if (!list_is_empty(l2cb.rcv_pending_q)) {
750     alarm_set_on_queue(l2cb.receive_hold_timer, BT_1SEC_TIMEOUT_MS,
751                        l2c_receive_hold_timer_timeout, NULL,
752                        btu_general_alarm_queue);
753   }
754 }
755 
756 /*******************************************************************************
757  *
758  * Function         l2c_init
759  *
760  * Description      This function is called once at startup to initialize
761  *                  all the L2CAP structures
762  *
763  * Returns          void
764  *
765  ******************************************************************************/
l2c_init(void)766 void l2c_init(void) {
767   int16_t xx;
768 
769   memset(&l2cb, 0, sizeof(tL2C_CB));
770   /* the psm is increased by 2 before being used */
771   l2cb.dyn_psm = 0xFFF;
772 
773   /* Put all the channel control blocks on the free queue */
774   for (xx = 0; xx < MAX_L2CAP_CHANNELS - 1; xx++) {
775     l2cb.ccb_pool[xx].p_next_ccb = &l2cb.ccb_pool[xx + 1];
776   }
777 
778 #if (L2CAP_NON_FLUSHABLE_PB_INCLUDED == TRUE)
779   /* it will be set to L2CAP_PKT_START_NON_FLUSHABLE if controller supports */
780   l2cb.non_flushable_pbf = L2CAP_PKT_START << L2CAP_PKT_TYPE_SHIFT;
781 #endif
782 
783   l2cb.p_free_ccb_first = &l2cb.ccb_pool[0];
784   l2cb.p_free_ccb_last = &l2cb.ccb_pool[MAX_L2CAP_CHANNELS - 1];
785 
786 #ifdef L2CAP_DESIRED_LINK_ROLE
787   l2cb.desire_role = L2CAP_DESIRED_LINK_ROLE;
788 #else
789   l2cb.desire_role = HCI_ROLE_SLAVE;
790 #endif
791 
792   /* Set the default idle timeout */
793   l2cb.idle_timeout = L2CAP_LINK_INACTIVITY_TOUT;
794 
795 #if defined(L2CAP_INITIAL_TRACE_LEVEL)
796   l2cb.l2cap_trace_level = L2CAP_INITIAL_TRACE_LEVEL;
797 #else
798   l2cb.l2cap_trace_level = BT_TRACE_LEVEL_NONE; /* No traces */
799 #endif
800 
801 #if (L2CAP_CONFORMANCE_TESTING == TRUE)
802   /* Conformance testing needs a dynamic response */
803   l2cb.test_info_resp = L2CAP_EXTFEA_SUPPORTED_MASK;
804 #endif
805 
806 /* Number of ACL buffers to use for high priority channel */
807 #if (L2CAP_HIGH_PRI_CHAN_QUOTA_IS_CONFIGURABLE == TRUE)
808   l2cb.high_pri_min_xmit_quota = L2CAP_HIGH_PRI_MIN_XMIT_QUOTA;
809 #endif
810 
811   l2cb.l2c_ble_fixed_chnls_mask = L2CAP_FIXED_CHNL_ATT_BIT |
812                                   L2CAP_FIXED_CHNL_BLE_SIG_BIT |
813                                   L2CAP_FIXED_CHNL_SMP_BIT;
814 
815   l2cb.rcv_pending_q = list_new(NULL);
816   CHECK(l2cb.rcv_pending_q != NULL);
817 
818   l2cb.receive_hold_timer = alarm_new("l2c.receive_hold_timer");
819 }
820 
l2c_free(void)821 void l2c_free(void) {
822   list_free(l2cb.rcv_pending_q);
823   l2cb.rcv_pending_q = NULL;
824 }
825 
l2c_receive_hold_timer_timeout(UNUSED_ATTR void * data)826 void l2c_receive_hold_timer_timeout(UNUSED_ATTR void* data) {
827   /* Update the timeouts in the hold queue */
828   l2c_process_held_packets(true);
829 }
830 
l2c_ccb_timer_timeout(void * data)831 void l2c_ccb_timer_timeout(void* data) {
832   tL2C_CCB* p_ccb = (tL2C_CCB*)data;
833 
834   l2c_csm_execute(p_ccb, L2CEVT_TIMEOUT, NULL);
835 }
836 
l2c_fcrb_ack_timer_timeout(void * data)837 void l2c_fcrb_ack_timer_timeout(void* data) {
838   tL2C_CCB* p_ccb = (tL2C_CCB*)data;
839 
840   l2c_csm_execute(p_ccb, L2CEVT_ACK_TIMEOUT, NULL);
841 }
842 
l2c_lcb_timer_timeout(void * data)843 void l2c_lcb_timer_timeout(void* data) {
844   tL2C_LCB* p_lcb = (tL2C_LCB*)data;
845 
846   l2c_link_timeout(p_lcb);
847 }
848 
849 /*******************************************************************************
850  *
851  * Function         l2c_data_write
852  *
853  * Description      API functions call this function to write data.
854  *
855  * Returns          L2CAP_DW_SUCCESS, if data accepted, else false
856  *                  L2CAP_DW_CONGESTED, if data accepted and the channel is
857  *                                      congested
858  *                  L2CAP_DW_FAILED, if error
859  *
860  ******************************************************************************/
l2c_data_write(uint16_t cid,BT_HDR * p_data,uint16_t flags)861 uint8_t l2c_data_write(uint16_t cid, BT_HDR* p_data, uint16_t flags) {
862   tL2C_CCB* p_ccb;
863 
864   /* Find the channel control block. We don't know the link it is on. */
865   p_ccb = l2cu_find_ccb_by_cid(NULL, cid);
866   if (p_ccb == NULL) {
867     L2CAP_TRACE_WARNING("L2CAP - no CCB for L2CA_DataWrite, CID: %d", cid);
868     osi_free(p_data);
869     return (L2CAP_DW_FAILED);
870   }
871 
872 #ifndef TESTER /* Tester may send any amount of data. otherwise sending \
873                   message                                               \
874                   bigger than mtu size of peer is a violation of protocol */
875   uint16_t mtu;
876 
877   if (p_ccb->p_lcb->transport == BT_TRANSPORT_LE)
878     mtu = p_ccb->peer_conn_cfg.mtu;
879   else
880     mtu = p_ccb->peer_cfg.mtu;
881 
882   if (p_data->len > mtu) {
883     L2CAP_TRACE_WARNING(
884         "L2CAP - CID: 0x%04x  cannot send message bigger than peer's mtu size: "
885         "len=%u mtu=%u",
886         cid, p_data->len, mtu);
887     osi_free(p_data);
888     return (L2CAP_DW_FAILED);
889   }
890 #endif
891 
892   /* channel based, packet based flushable or non-flushable */
893   p_data->layer_specific = flags;
894 
895   /* If already congested, do not accept any more packets */
896   if (p_ccb->cong_sent) {
897     L2CAP_TRACE_ERROR(
898         "L2CAP - CID: 0x%04x cannot send, already congested  "
899         "xmit_hold_q.count: %u  buff_quota: %u",
900         p_ccb->local_cid, fixed_queue_length(p_ccb->xmit_hold_q),
901         p_ccb->buff_quota);
902 
903     osi_free(p_data);
904     return (L2CAP_DW_FAILED);
905   }
906 
907   l2c_csm_execute(p_ccb, L2CEVT_L2CA_DATA_WRITE, p_data);
908 
909   if (p_ccb->cong_sent) return (L2CAP_DW_CONGESTED);
910 
911   return (L2CAP_DW_SUCCESS);
912 }
913