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/******************************************************************************/
44/*            L O C A L    F U N C T I O N     P R O T O T Y P E S            */
45/******************************************************************************/
46static void process_l2cap_cmd(tL2C_LCB* p_lcb, uint8_t* p, uint16_t pkt_len);
47
48/******************************************************************************/
49/*               G L O B A L      L 2 C A P       D A T A                     */
50/******************************************************************************/
51tL2C_CB l2cb;
52
53/*******************************************************************************
54 *
55 * Function         l2c_rcv_acl_data
56 *
57 * Description      This function is called from the HCI Interface when an ACL
58 *                  data packet is received.
59 *
60 * Returns          void
61 *
62 ******************************************************************************/
63void l2c_rcv_acl_data(BT_HDR* p_msg) {
64  uint8_t* p = (uint8_t*)(p_msg + 1) + p_msg->offset;
65  uint16_t handle, hci_len;
66  uint8_t pkt_type;
67  tL2C_LCB* p_lcb;
68  tL2C_CCB* p_ccb = NULL;
69  uint16_t l2cap_len, rcv_cid, psm;
70  uint16_t credit;
71
72  /* Extract the handle */
73  STREAM_TO_UINT16(handle, p);
74  pkt_type = HCID_GET_EVENT(handle);
75  handle = HCID_GET_HANDLE(handle);
76
77  /* Since the HCI Transport is putting segmented packets back together, we */
78  /* should never get a valid packet with the type set to "continuation"    */
79  if (pkt_type != L2CAP_PKT_CONTINUE) {
80    /* Find the LCB based on the handle */
81    p_lcb = l2cu_find_lcb_by_handle(handle);
82    if (p_lcb == NULL) {
83      uint8_t cmd_code;
84
85      /* There is a slight possibility (specifically with USB) that we get an */
86      /* L2CAP connection request before we get the HCI connection complete.  */
87      /* So for these types of messages, hold them for up to 2 seconds.       */
88      STREAM_TO_UINT16(hci_len, p);
89      STREAM_TO_UINT16(l2cap_len, p);
90      STREAM_TO_UINT16(rcv_cid, p);
91      STREAM_TO_UINT8(cmd_code, p);
92
93      if ((p_msg->layer_specific == 0) && (rcv_cid == L2CAP_SIGNALLING_CID) &&
94          (cmd_code == L2CAP_CMD_INFO_REQ || cmd_code == L2CAP_CMD_CONN_REQ)) {
95        L2CAP_TRACE_WARNING(
96            "L2CAP - holding ACL for unknown handle:%d ls:%d"
97            "  cid:%d opcode:%d cur count:%d",
98            handle, p_msg->layer_specific, rcv_cid, cmd_code,
99            list_length(l2cb.rcv_pending_q));
100        p_msg->layer_specific = 2;
101        list_append(l2cb.rcv_pending_q, p_msg);
102
103        if (list_length(l2cb.rcv_pending_q) == 1) {
104          alarm_set_on_mloop(l2cb.receive_hold_timer, BT_1SEC_TIMEOUT_MS,
105                             l2c_receive_hold_timer_timeout, NULL);
106        }
107
108        return;
109      } else {
110        L2CAP_TRACE_ERROR(
111            "L2CAP - rcvd ACL for unknown handle:%d ls:%d cid:%d"
112            " opcode:%d cur count:%d",
113            handle, p_msg->layer_specific, rcv_cid, cmd_code,
114            list_length(l2cb.rcv_pending_q));
115      }
116      osi_free(p_msg);
117      return;
118    }
119  } else {
120    L2CAP_TRACE_WARNING("L2CAP - expected pkt start or complete, got: %d",
121                        pkt_type);
122    osi_free(p_msg);
123    return;
124  }
125
126  /* Extract the length and update the buffer header */
127  STREAM_TO_UINT16(hci_len, p);
128  p_msg->offset += 4;
129
130  if (hci_len < L2CAP_PKT_OVERHEAD) {
131    /* Must receive at least the L2CAP length and CID */
132    L2CAP_TRACE_WARNING("L2CAP - got incorrect hci header");
133    osi_free(p_msg);
134    return;
135  }
136
137  /* Extract the length and CID */
138  STREAM_TO_UINT16(l2cap_len, p);
139  STREAM_TO_UINT16(rcv_cid, p);
140
141  /* for BLE channel, always notify connection when ACL data received on the
142   * link */
143  if (p_lcb && p_lcb->transport == BT_TRANSPORT_LE &&
144      p_lcb->link_state != LST_DISCONNECTING)
145    /* only process fixed channel data as channel open indication when link is
146     * not in disconnecting mode */
147    l2cble_notify_le_connection(p_lcb->remote_bd_addr);
148
149  /* Find the CCB for this CID */
150  if (rcv_cid >= L2CAP_BASE_APPL_CID) {
151    p_ccb = l2cu_find_ccb_by_cid(p_lcb, rcv_cid);
152    if (p_ccb == NULL) {
153      L2CAP_TRACE_WARNING("L2CAP - unknown CID: 0x%04x", rcv_cid);
154      osi_free(p_msg);
155      return;
156    }
157  }
158
159  p_msg->len = hci_len - L2CAP_PKT_OVERHEAD;
160  p_msg->offset += L2CAP_PKT_OVERHEAD;
161
162  if (l2cap_len != p_msg->len) {
163    L2CAP_TRACE_WARNING("L2CAP - bad length in pkt. Exp: %d  Act: %d",
164                        l2cap_len, p_msg->len);
165
166    osi_free(p_msg);
167    return;
168  }
169
170  /* Send the data through the channel state machine */
171  if (rcv_cid == L2CAP_SIGNALLING_CID) {
172    process_l2cap_cmd(p_lcb, p, l2cap_len);
173    osi_free(p_msg);
174  } else if (rcv_cid == L2CAP_CONNECTIONLESS_CID) {
175    /* process_connectionless_data (p_lcb); */
176    STREAM_TO_UINT16(psm, p);
177    L2CAP_TRACE_DEBUG("GOT CONNECTIONLESS DATA PSM:%d", psm);
178
179#if (L2CAP_UCD_INCLUDED == TRUE)
180    /* if it is not broadcast, check UCD registration */
181    if (l2c_ucd_check_rx_pkts(p_lcb, p_msg)) {
182      /* nothing to do */
183    } else
184#endif
185      osi_free(p_msg);
186  } else if (rcv_cid == L2CAP_BLE_SIGNALLING_CID) {
187    l2cble_process_sig_cmd(p_lcb, p, l2cap_len);
188    osi_free(p_msg);
189  }
190#if (L2CAP_NUM_FIXED_CHNLS > 0)
191  else if ((rcv_cid >= L2CAP_FIRST_FIXED_CHNL) &&
192           (rcv_cid <= L2CAP_LAST_FIXED_CHNL) &&
193           (l2cb.fixed_reg[rcv_cid - L2CAP_FIRST_FIXED_CHNL]
194                .pL2CA_FixedData_Cb != NULL)) {
195    /* If no CCB for this channel, allocate one */
196    if (p_lcb &&
197        /* only process fixed channel data when link is open or wait for data
198           indication */
199        (p_lcb->link_state != LST_DISCONNECTING) &&
200        l2cu_initialize_fixed_ccb(
201            p_lcb, rcv_cid, &l2cb.fixed_reg[rcv_cid - L2CAP_FIRST_FIXED_CHNL]
202                                 .fixed_chnl_opts)) {
203      p_ccb = p_lcb->p_fixed_ccbs[rcv_cid - L2CAP_FIRST_FIXED_CHNL];
204
205      if (p_ccb->peer_cfg.fcr.mode != L2CAP_FCR_BASIC_MODE)
206        l2c_fcr_proc_pdu(p_ccb, p_msg);
207      else
208        (*l2cb.fixed_reg[rcv_cid - L2CAP_FIRST_FIXED_CHNL].pL2CA_FixedData_Cb)(
209            rcv_cid, p_lcb->remote_bd_addr, p_msg);
210    } else
211      osi_free(p_msg);
212  }
213#endif
214
215  else {
216    if (p_ccb == NULL)
217      osi_free(p_msg);
218    else {
219      if (p_lcb->transport == BT_TRANSPORT_LE) {
220        l2c_lcc_proc_pdu(p_ccb, p_msg);
221        // Got a pkt, valid send out credits to the peer device
222        credit = L2CAP_LE_DEFAULT_CREDIT;
223        l2c_csm_execute(p_ccb, L2CEVT_L2CA_SEND_FLOW_CONTROL_CREDIT, &credit);
224      } else {
225        /* Basic mode packets go straight to the state machine */
226        if (p_ccb->peer_cfg.fcr.mode == L2CAP_FCR_BASIC_MODE)
227          l2c_csm_execute(p_ccb, L2CEVT_L2CAP_DATA, p_msg);
228        else {
229          /* eRTM or streaming mode, so we need to validate states first */
230          if ((p_ccb->chnl_state == CST_OPEN) ||
231              (p_ccb->chnl_state == CST_CONFIG))
232            l2c_fcr_proc_pdu(p_ccb, p_msg);
233          else
234            osi_free(p_msg);
235        }
236      }
237    }
238  }
239}
240
241/*******************************************************************************
242 *
243 * Function         process_l2cap_cmd
244 *
245 * Description      This function is called when a packet is received on the
246 *                  L2CAP signalling CID
247 *
248 * Returns          void
249 *
250 ******************************************************************************/
251static void process_l2cap_cmd(tL2C_LCB* p_lcb, uint8_t* p, uint16_t pkt_len) {
252  uint8_t *p_pkt_end, *p_next_cmd, *p_cfg_end, *p_cfg_start;
253  uint8_t cmd_code, cfg_code, cfg_len, id;
254  tL2C_CONN_INFO con_info;
255  tL2CAP_CFG_INFO cfg_info;
256  uint16_t rej_reason, rej_mtu, lcid, rcid, info_type;
257  tL2C_CCB* p_ccb;
258  tL2C_RCB* p_rcb;
259  bool cfg_rej, pkt_size_rej = false;
260  uint16_t cfg_rej_len, cmd_len;
261  uint16_t result;
262  tL2C_CONN_INFO ci;
263
264  /* if l2cap command received in CID 1 on top of an LE link, ignore this
265   * command */
266  if (p_lcb->transport == BT_TRANSPORT_LE) return;
267
268  /* Reject the packet if it exceeds the default Signalling Channel MTU */
269  if (pkt_len > L2CAP_DEFAULT_MTU) {
270    /* Core Spec requires a single response to the first command found in a
271    *multi-command
272    ** L2cap packet.  If only responses in the packet, then it will be ignored.
273    ** Here we simply mark the bad packet and decide which cmd ID to reject
274    *later
275    */
276    pkt_size_rej = true;
277    L2CAP_TRACE_ERROR("L2CAP SIG MTU Pkt Len Exceeded (672) -> pkt_len: %d",
278                      pkt_len);
279  }
280
281  p_next_cmd = p;
282  p_pkt_end = p + pkt_len;
283
284  memset(&cfg_info, 0, sizeof(cfg_info));
285
286  /* An L2CAP packet may contain multiple commands */
287  while (true) {
288    /* Smallest command is 4 bytes */
289    p = p_next_cmd;
290    if (p > (p_pkt_end - 4)) break;
291
292    STREAM_TO_UINT8(cmd_code, p);
293    STREAM_TO_UINT8(id, p);
294    STREAM_TO_UINT16(cmd_len, p);
295
296    if (cmd_len > BT_SMALL_BUFFER_SIZE) {
297      L2CAP_TRACE_WARNING("L2CAP - Invalid MTU Size");
298      l2cu_send_peer_cmd_reject(p_lcb, L2CAP_CMD_REJ_MTU_EXCEEDED, id, 0, 0);
299      return;
300    }
301
302    /* Check command length does not exceed packet length */
303    p_next_cmd = p + cmd_len;
304    if (p_next_cmd > p_pkt_end) {
305      L2CAP_TRACE_WARNING("Command len bad  pkt_len: %d  cmd_len: %d  code: %d",
306                          pkt_len, cmd_len, cmd_code);
307      break;
308    }
309
310    L2CAP_TRACE_DEBUG("cmd_code: %d, id:%d, cmd_len:%d", cmd_code, id, cmd_len);
311
312    /* Bad L2CAP packet length, look or cmd to reject */
313    if (pkt_size_rej) {
314      /* If command found rejected it and we're done, otherwise keep looking */
315      if (l2c_is_cmd_rejected(cmd_code, id, p_lcb))
316        return;
317      else
318        continue; /* Look for next cmd/response in current packet */
319    }
320
321    switch (cmd_code) {
322      case L2CAP_CMD_REJECT:
323        if (p + 2 > p_next_cmd) {
324          android_errorWriteLog(0x534e4554, "74202041");
325          return;
326        }
327        STREAM_TO_UINT16(rej_reason, p);
328        if (rej_reason == L2CAP_CMD_REJ_MTU_EXCEEDED) {
329          if (p + 2 > p_next_cmd) {
330            android_errorWriteLog(0x534e4554, "74202041");
331            return;
332          }
333          STREAM_TO_UINT16(rej_mtu, p);
334          /* What to do with the MTU reject ? We have negotiated an MTU. For now
335           */
336          /* we will ignore it and let a higher protocol timeout take care of it
337           */
338
339          L2CAP_TRACE_WARNING("L2CAP - MTU rej Handle: %d MTU: %d",
340                              p_lcb->handle, rej_mtu);
341        }
342        if (rej_reason == L2CAP_CMD_REJ_INVALID_CID) {
343          if (p + 4 > p_next_cmd) {
344            android_errorWriteLog(0x534e4554, "74202041");
345            return;
346          }
347          STREAM_TO_UINT16(rcid, p);
348          STREAM_TO_UINT16(lcid, p);
349
350          L2CAP_TRACE_WARNING(
351              "L2CAP - rej with CID invalid, LCID: 0x%04x RCID: 0x%04x", lcid,
352              rcid);
353
354          /* Remote CID invalid. Treat as a disconnect */
355          p_ccb = l2cu_find_ccb_by_cid(p_lcb, lcid);
356          if ((p_ccb != NULL) && (p_ccb->remote_cid == rcid)) {
357            /* Fake link disconnect - no reply is generated */
358            l2c_csm_execute(p_ccb, L2CEVT_LP_DISCONNECT_IND, NULL);
359          }
360        }
361
362        /* SonyEricsson Info request Bug workaround (Continue connection) */
363        else if (rej_reason == L2CAP_CMD_REJ_NOT_UNDERSTOOD &&
364                 p_lcb->w4_info_rsp) {
365          alarm_cancel(p_lcb->info_resp_timer);
366
367          p_lcb->w4_info_rsp = false;
368          ci.status = HCI_SUCCESS;
369          ci.bd_addr = p_lcb->remote_bd_addr;
370
371          /* For all channels, send the event through their FSMs */
372          for (p_ccb = p_lcb->ccb_queue.p_first_ccb; p_ccb;
373               p_ccb = p_ccb->p_next_ccb) {
374            l2c_csm_execute(p_ccb, L2CEVT_L2CAP_INFO_RSP, &ci);
375          }
376        }
377        break;
378
379      case L2CAP_CMD_CONN_REQ:
380        if (p + 4 > p_next_cmd) {
381          android_errorWriteLog(0x534e4554, "74202041");
382          return;
383        }
384        STREAM_TO_UINT16(con_info.psm, p);
385        STREAM_TO_UINT16(rcid, p);
386        p_rcb = l2cu_find_rcb_by_psm(con_info.psm);
387        if (p_rcb == NULL) {
388          L2CAP_TRACE_WARNING("L2CAP - rcvd conn req for unknown PSM: %d",
389                              con_info.psm);
390          l2cu_reject_connection(p_lcb, rcid, id, L2CAP_CONN_NO_PSM);
391          break;
392        } else {
393          if (!p_rcb->api.pL2CA_ConnectInd_Cb) {
394            L2CAP_TRACE_WARNING(
395                "L2CAP - rcvd conn req for outgoing-only connection PSM: %d",
396                con_info.psm);
397            l2cu_reject_connection(p_lcb, rcid, id, L2CAP_CONN_NO_PSM);
398            break;
399          }
400        }
401        p_ccb = l2cu_allocate_ccb(p_lcb, 0);
402        if (p_ccb == NULL) {
403          L2CAP_TRACE_ERROR("L2CAP - unable to allocate CCB");
404          l2cu_reject_connection(p_lcb, rcid, id, L2CAP_CONN_NO_RESOURCES);
405          break;
406        }
407        p_ccb->remote_id = id;
408        p_ccb->p_rcb = p_rcb;
409        p_ccb->remote_cid = rcid;
410
411        l2c_csm_execute(p_ccb, L2CEVT_L2CAP_CONNECT_REQ, &con_info);
412        break;
413
414      case L2CAP_CMD_CONN_RSP:
415        if (p + 8 > p_next_cmd) {
416          android_errorWriteLog(0x534e4554, "74202041");
417          return;
418        }
419        STREAM_TO_UINT16(con_info.remote_cid, p);
420        STREAM_TO_UINT16(lcid, p);
421        STREAM_TO_UINT16(con_info.l2cap_result, p);
422        STREAM_TO_UINT16(con_info.l2cap_status, p);
423
424        p_ccb = l2cu_find_ccb_by_cid(p_lcb, lcid);
425        if (p_ccb == NULL) {
426          L2CAP_TRACE_WARNING("L2CAP - no CCB for conn rsp, LCID: %d RCID: %d",
427                              lcid, con_info.remote_cid);
428          break;
429        }
430        if (p_ccb->local_id != id) {
431          L2CAP_TRACE_WARNING("L2CAP - con rsp - bad ID. Exp: %d Got: %d",
432                              p_ccb->local_id, id);
433          break;
434        }
435
436        if (con_info.l2cap_result == L2CAP_CONN_OK)
437          l2c_csm_execute(p_ccb, L2CEVT_L2CAP_CONNECT_RSP, &con_info);
438        else if (con_info.l2cap_result == L2CAP_CONN_PENDING)
439          l2c_csm_execute(p_ccb, L2CEVT_L2CAP_CONNECT_RSP_PND, &con_info);
440        else
441          l2c_csm_execute(p_ccb, L2CEVT_L2CAP_CONNECT_RSP_NEG, &con_info);
442
443        break;
444
445      case L2CAP_CMD_CONFIG_REQ:
446        p_cfg_end = p + cmd_len;
447        cfg_rej = false;
448        cfg_rej_len = 0;
449
450        if (p + 4 > p_next_cmd) {
451          android_errorWriteLog(0x534e4554, "74202041");
452          return;
453        }
454        STREAM_TO_UINT16(lcid, p);
455        STREAM_TO_UINT16(cfg_info.flags, p);
456
457        p_cfg_start = p;
458
459        cfg_info.flush_to_present = cfg_info.mtu_present =
460            cfg_info.qos_present = cfg_info.fcr_present = cfg_info.fcs_present =
461                false;
462
463        while (p < p_cfg_end) {
464          if (p + 2 > p_next_cmd) {
465            android_errorWriteLog(0x534e4554, "74202041");
466            return;
467          }
468          STREAM_TO_UINT8(cfg_code, p);
469          STREAM_TO_UINT8(cfg_len, p);
470
471          switch (cfg_code & 0x7F) {
472            case L2CAP_CFG_TYPE_MTU:
473              cfg_info.mtu_present = true;
474              if (p + 2 > p_next_cmd) {
475                android_errorWriteLog(0x534e4554, "74202041");
476                return;
477              }
478              STREAM_TO_UINT16(cfg_info.mtu, p);
479              break;
480
481            case L2CAP_CFG_TYPE_FLUSH_TOUT:
482              cfg_info.flush_to_present = true;
483              if (p + 2 > p_next_cmd) {
484                android_errorWriteLog(0x534e4554, "74202041");
485                return;
486              }
487              STREAM_TO_UINT16(cfg_info.flush_to, p);
488              break;
489
490            case L2CAP_CFG_TYPE_QOS:
491              cfg_info.qos_present = true;
492              if (p + 2 + 5 * 4 > p_next_cmd) {
493                android_errorWriteLog(0x534e4554, "74202041");
494                return;
495              }
496              STREAM_TO_UINT8(cfg_info.qos.qos_flags, p);
497              STREAM_TO_UINT8(cfg_info.qos.service_type, p);
498              STREAM_TO_UINT32(cfg_info.qos.token_rate, p);
499              STREAM_TO_UINT32(cfg_info.qos.token_bucket_size, p);
500              STREAM_TO_UINT32(cfg_info.qos.peak_bandwidth, p);
501              STREAM_TO_UINT32(cfg_info.qos.latency, p);
502              STREAM_TO_UINT32(cfg_info.qos.delay_variation, p);
503              break;
504
505            case L2CAP_CFG_TYPE_FCR:
506              cfg_info.fcr_present = true;
507              if (p + 3 + 3 * 2 > p_next_cmd) {
508                android_errorWriteLog(0x534e4554, "74202041");
509                return;
510              }
511              STREAM_TO_UINT8(cfg_info.fcr.mode, p);
512              STREAM_TO_UINT8(cfg_info.fcr.tx_win_sz, p);
513              STREAM_TO_UINT8(cfg_info.fcr.max_transmit, p);
514              STREAM_TO_UINT16(cfg_info.fcr.rtrans_tout, p);
515              STREAM_TO_UINT16(cfg_info.fcr.mon_tout, p);
516              STREAM_TO_UINT16(cfg_info.fcr.mps, p);
517              break;
518
519            case L2CAP_CFG_TYPE_FCS:
520              cfg_info.fcs_present = true;
521              if (p + 1 > p_next_cmd) {
522                android_errorWriteLog(0x534e4554, "74202041");
523                return;
524              }
525              STREAM_TO_UINT8(cfg_info.fcs, p);
526              break;
527
528            case L2CAP_CFG_TYPE_EXT_FLOW:
529              cfg_info.ext_flow_spec_present = true;
530              if (p + 2 + 2 + 3 * 4 > p_next_cmd) {
531                android_errorWriteLog(0x534e4554, "74202041");
532                return;
533              }
534              STREAM_TO_UINT8(cfg_info.ext_flow_spec.id, p);
535              STREAM_TO_UINT8(cfg_info.ext_flow_spec.stype, p);
536              STREAM_TO_UINT16(cfg_info.ext_flow_spec.max_sdu_size, p);
537              STREAM_TO_UINT32(cfg_info.ext_flow_spec.sdu_inter_time, p);
538              STREAM_TO_UINT32(cfg_info.ext_flow_spec.access_latency, p);
539              STREAM_TO_UINT32(cfg_info.ext_flow_spec.flush_timeout, p);
540              break;
541
542            default:
543              /* sanity check option length */
544              if ((cfg_len + L2CAP_CFG_OPTION_OVERHEAD) <= cmd_len) {
545                p += cfg_len;
546                if ((cfg_code & 0x80) == 0) {
547                  cfg_rej_len += cfg_len + L2CAP_CFG_OPTION_OVERHEAD;
548                  cfg_rej = true;
549                }
550              }
551              /* bad length; force loop exit */
552              else {
553                p = p_cfg_end;
554                cfg_rej = true;
555              }
556              break;
557          }
558        }
559
560        p_ccb = l2cu_find_ccb_by_cid(p_lcb, lcid);
561        if (p_ccb != NULL) {
562          p_ccb->remote_id = id;
563          if (cfg_rej) {
564            l2cu_send_peer_config_rej(
565                p_ccb, p_cfg_start, (uint16_t)(cmd_len - L2CAP_CONFIG_REQ_LEN),
566                cfg_rej_len);
567          } else {
568            l2c_csm_execute(p_ccb, L2CEVT_L2CAP_CONFIG_REQ, &cfg_info);
569          }
570        } else {
571          /* updated spec says send command reject on invalid cid */
572          l2cu_send_peer_cmd_reject(p_lcb, L2CAP_CMD_REJ_INVALID_CID, id, 0, 0);
573        }
574        break;
575
576      case L2CAP_CMD_CONFIG_RSP:
577        p_cfg_end = p + cmd_len;
578        if (p + 6 > p_next_cmd) {
579          android_errorWriteLog(0x534e4554, "74202041");
580          return;
581        }
582        STREAM_TO_UINT16(lcid, p);
583        STREAM_TO_UINT16(cfg_info.flags, p);
584        STREAM_TO_UINT16(cfg_info.result, p);
585
586        cfg_info.flush_to_present = cfg_info.mtu_present =
587            cfg_info.qos_present = cfg_info.fcr_present = cfg_info.fcs_present =
588                false;
589
590        while (p < p_cfg_end) {
591          if (p + 2 > p_next_cmd) {
592            android_errorWriteLog(0x534e4554, "74202041");
593            return;
594          }
595          STREAM_TO_UINT8(cfg_code, p);
596          STREAM_TO_UINT8(cfg_len, p);
597
598          switch (cfg_code & 0x7F) {
599            case L2CAP_CFG_TYPE_MTU:
600              cfg_info.mtu_present = true;
601              if (p + 2 > p_next_cmd) {
602                android_errorWriteLog(0x534e4554, "74202041");
603                return;
604              }
605              STREAM_TO_UINT16(cfg_info.mtu, p);
606              break;
607
608            case L2CAP_CFG_TYPE_FLUSH_TOUT:
609              cfg_info.flush_to_present = true;
610              if (p + 2 > p_next_cmd) {
611                android_errorWriteLog(0x534e4554, "74202041");
612                return;
613              }
614              STREAM_TO_UINT16(cfg_info.flush_to, p);
615              break;
616
617            case L2CAP_CFG_TYPE_QOS:
618              cfg_info.qos_present = true;
619              if (p + 2 + 5 * 4 > p_next_cmd) {
620                android_errorWriteLog(0x534e4554, "74202041");
621                return;
622              }
623              STREAM_TO_UINT8(cfg_info.qos.qos_flags, p);
624              STREAM_TO_UINT8(cfg_info.qos.service_type, p);
625              STREAM_TO_UINT32(cfg_info.qos.token_rate, p);
626              STREAM_TO_UINT32(cfg_info.qos.token_bucket_size, p);
627              STREAM_TO_UINT32(cfg_info.qos.peak_bandwidth, p);
628              STREAM_TO_UINT32(cfg_info.qos.latency, p);
629              STREAM_TO_UINT32(cfg_info.qos.delay_variation, p);
630              break;
631
632            case L2CAP_CFG_TYPE_FCR:
633              cfg_info.fcr_present = true;
634              if (p + 3 + 3 * 2 > p_next_cmd) {
635                android_errorWriteLog(0x534e4554, "74202041");
636                return;
637              }
638              STREAM_TO_UINT8(cfg_info.fcr.mode, p);
639              STREAM_TO_UINT8(cfg_info.fcr.tx_win_sz, p);
640              STREAM_TO_UINT8(cfg_info.fcr.max_transmit, p);
641              STREAM_TO_UINT16(cfg_info.fcr.rtrans_tout, p);
642              STREAM_TO_UINT16(cfg_info.fcr.mon_tout, p);
643              STREAM_TO_UINT16(cfg_info.fcr.mps, p);
644              break;
645
646            case L2CAP_CFG_TYPE_FCS:
647              cfg_info.fcs_present = true;
648              if (p + 1 > p_next_cmd) {
649                android_errorWriteLog(0x534e4554, "74202041");
650                return;
651              }
652              STREAM_TO_UINT8(cfg_info.fcs, p);
653              break;
654
655            case L2CAP_CFG_TYPE_EXT_FLOW:
656              cfg_info.ext_flow_spec_present = true;
657              if (p + 2 + 2 + 3 * 4 > p_next_cmd) {
658                android_errorWriteLog(0x534e4554, "74202041");
659                return;
660              }
661              STREAM_TO_UINT8(cfg_info.ext_flow_spec.id, p);
662              STREAM_TO_UINT8(cfg_info.ext_flow_spec.stype, p);
663              STREAM_TO_UINT16(cfg_info.ext_flow_spec.max_sdu_size, p);
664              STREAM_TO_UINT32(cfg_info.ext_flow_spec.sdu_inter_time, p);
665              STREAM_TO_UINT32(cfg_info.ext_flow_spec.access_latency, p);
666              STREAM_TO_UINT32(cfg_info.ext_flow_spec.flush_timeout, p);
667              break;
668          }
669        }
670
671        p_ccb = l2cu_find_ccb_by_cid(p_lcb, lcid);
672        if (p_ccb != NULL) {
673          if (p_ccb->local_id != id) {
674            L2CAP_TRACE_WARNING("L2CAP - cfg rsp - bad ID. Exp: %d Got: %d",
675                                p_ccb->local_id, id);
676            break;
677          }
678          if ((cfg_info.result == L2CAP_CFG_OK) ||
679              (cfg_info.result == L2CAP_CFG_PENDING))
680            l2c_csm_execute(p_ccb, L2CEVT_L2CAP_CONFIG_RSP, &cfg_info);
681          else
682            l2c_csm_execute(p_ccb, L2CEVT_L2CAP_CONFIG_RSP_NEG, &cfg_info);
683        } else {
684          L2CAP_TRACE_WARNING("L2CAP - rcvd cfg rsp for unknown CID: 0x%04x",
685                              lcid);
686        }
687        break;
688
689      case L2CAP_CMD_DISC_REQ:
690        if (p + 4 > p_next_cmd) {
691          android_errorWriteLog(0x534e4554, "74202041");
692          return;
693        }
694        STREAM_TO_UINT16(lcid, p);
695        STREAM_TO_UINT16(rcid, p);
696
697        p_ccb = l2cu_find_ccb_by_cid(p_lcb, lcid);
698        if (p_ccb != NULL) {
699          if (p_ccb->remote_cid == rcid) {
700            p_ccb->remote_id = id;
701            l2c_csm_execute(p_ccb, L2CEVT_L2CAP_DISCONNECT_REQ, &con_info);
702          }
703        } else
704          l2cu_send_peer_disc_rsp(p_lcb, id, lcid, rcid);
705
706        break;
707
708      case L2CAP_CMD_DISC_RSP:
709        if (p + 4 > p_next_cmd) {
710          android_errorWriteLog(0x534e4554, "74202041");
711          return;
712        }
713        STREAM_TO_UINT16(rcid, p);
714        STREAM_TO_UINT16(lcid, p);
715
716        p_ccb = l2cu_find_ccb_by_cid(p_lcb, lcid);
717        if (p_ccb != NULL) {
718          if ((p_ccb->remote_cid == rcid) && (p_ccb->local_id == id)) {
719            l2c_csm_execute(p_ccb, L2CEVT_L2CAP_DISCONNECT_RSP, &con_info);
720          }
721        }
722        break;
723
724      case L2CAP_CMD_ECHO_REQ:
725        l2cu_send_peer_echo_rsp(p_lcb, id, p, cmd_len);
726        break;
727
728      case L2CAP_CMD_ECHO_RSP:
729        if (p_lcb->p_echo_rsp_cb) {
730          tL2CA_ECHO_RSP_CB* p_cb = p_lcb->p_echo_rsp_cb;
731
732          /* Zero out the callback in case app immediately calls us again */
733          p_lcb->p_echo_rsp_cb = NULL;
734
735          (*p_cb)(L2CAP_PING_RESULT_OK);
736        }
737        break;
738
739      case L2CAP_CMD_INFO_REQ:
740        if (p + 2 > p_next_cmd) {
741          android_errorWriteLog(0x534e4554, "74202041");
742          return;
743        }
744        STREAM_TO_UINT16(info_type, p);
745        l2cu_send_peer_info_rsp(p_lcb, id, info_type);
746        break;
747
748      case L2CAP_CMD_INFO_RSP:
749        /* Stop the link connect timer if sent before L2CAP connection is up */
750        if (p_lcb->w4_info_rsp) {
751          alarm_cancel(p_lcb->info_resp_timer);
752          p_lcb->w4_info_rsp = false;
753        }
754
755        if (p + 4 > p_next_cmd) {
756          android_errorWriteLog(0x534e4554, "74202041");
757          return;
758        }
759        STREAM_TO_UINT16(info_type, p);
760        STREAM_TO_UINT16(result, p);
761
762        p_lcb->info_rx_bits |= (1 << info_type);
763
764        if ((info_type == L2CAP_EXTENDED_FEATURES_INFO_TYPE) &&
765            (result == L2CAP_INFO_RESP_RESULT_SUCCESS)) {
766          if (p + 4 > p_next_cmd) {
767            android_errorWriteLog(0x534e4554, "74202041");
768            return;
769          }
770          STREAM_TO_UINT32(p_lcb->peer_ext_fea, p);
771
772#if (L2CAP_NUM_FIXED_CHNLS > 0)
773          if (p_lcb->peer_ext_fea & L2CAP_EXTFEA_FIXED_CHNLS) {
774            l2cu_send_peer_info_req(p_lcb, L2CAP_FIXED_CHANNELS_INFO_TYPE);
775            break;
776          } else {
777            l2cu_process_fixed_chnl_resp(p_lcb);
778          }
779#endif
780        }
781
782#if (L2CAP_NUM_FIXED_CHNLS > 0)
783        if (info_type == L2CAP_FIXED_CHANNELS_INFO_TYPE) {
784          if (result == L2CAP_INFO_RESP_RESULT_SUCCESS) {
785            memcpy(p_lcb->peer_chnl_mask, p, L2CAP_FIXED_CHNL_ARRAY_SIZE);
786          }
787
788          l2cu_process_fixed_chnl_resp(p_lcb);
789        }
790#endif
791#if (L2CAP_UCD_INCLUDED == TRUE)
792        else if (info_type == L2CAP_CONNLESS_MTU_INFO_TYPE) {
793          if (result == L2CAP_INFO_RESP_RESULT_SUCCESS) {
794            STREAM_TO_UINT16(p_lcb->ucd_mtu, p);
795          }
796        }
797#endif
798
799        ci.status = HCI_SUCCESS;
800        ci.bd_addr = p_lcb->remote_bd_addr;
801        for (p_ccb = p_lcb->ccb_queue.p_first_ccb; p_ccb;
802             p_ccb = p_ccb->p_next_ccb) {
803          l2c_csm_execute(p_ccb, L2CEVT_L2CAP_INFO_RSP, &ci);
804        }
805        break;
806
807      default:
808        L2CAP_TRACE_WARNING("L2CAP - bad cmd code: %d", cmd_code);
809        l2cu_send_peer_cmd_reject(p_lcb, L2CAP_CMD_REJ_NOT_UNDERSTOOD, id, 0,
810                                  0);
811        return;
812    }
813  }
814}
815
816/*******************************************************************************
817 *
818 * Function         l2c_process_held_packets
819 *
820 * Description      This function processes any L2CAP packets that arrived
821 *                  before the HCI connection complete arrived. It is a work
822 *                  around for badly behaved controllers.
823 *
824 * Returns          void
825 *
826 ******************************************************************************/
827void l2c_process_held_packets(bool timed_out) {
828  if (list_is_empty(l2cb.rcv_pending_q)) return;
829
830  if (!timed_out) {
831    alarm_cancel(l2cb.receive_hold_timer);
832    L2CAP_TRACE_WARNING("L2CAP HOLD CONTINUE");
833  } else {
834    L2CAP_TRACE_WARNING("L2CAP HOLD TIMEOUT");
835  }
836
837  for (const list_node_t* node = list_begin(l2cb.rcv_pending_q);
838       node != list_end(l2cb.rcv_pending_q);) {
839    BT_HDR* p_buf = static_cast<BT_HDR*>(list_node(node));
840    node = list_next(node);
841    if (!timed_out || (!p_buf->layer_specific) ||
842        (--p_buf->layer_specific == 0)) {
843      list_remove(l2cb.rcv_pending_q, p_buf);
844      p_buf->layer_specific = 0xFFFF;
845      l2c_rcv_acl_data(p_buf);
846    }
847  }
848
849  /* If anyone still in the queue, restart the timeout */
850  if (!list_is_empty(l2cb.rcv_pending_q)) {
851    alarm_set_on_mloop(l2cb.receive_hold_timer, BT_1SEC_TIMEOUT_MS,
852                       l2c_receive_hold_timer_timeout, NULL);
853  }
854}
855
856/*******************************************************************************
857 *
858 * Function         l2c_init
859 *
860 * Description      This function is called once at startup to initialize
861 *                  all the L2CAP structures
862 *
863 * Returns          void
864 *
865 ******************************************************************************/
866void l2c_init(void) {
867  int16_t xx;
868
869  memset(&l2cb, 0, sizeof(tL2C_CB));
870  /* the psm is increased by 2 before being used */
871  l2cb.dyn_psm = 0xFFF;
872
873  /* Put all the channel control blocks on the free queue */
874  for (xx = 0; xx < MAX_L2CAP_CHANNELS - 1; xx++) {
875    l2cb.ccb_pool[xx].p_next_ccb = &l2cb.ccb_pool[xx + 1];
876  }
877
878#if (L2CAP_NON_FLUSHABLE_PB_INCLUDED == TRUE)
879  /* it will be set to L2CAP_PKT_START_NON_FLUSHABLE if controller supports */
880  l2cb.non_flushable_pbf = L2CAP_PKT_START << L2CAP_PKT_TYPE_SHIFT;
881#endif
882
883  l2cb.p_free_ccb_first = &l2cb.ccb_pool[0];
884  l2cb.p_free_ccb_last = &l2cb.ccb_pool[MAX_L2CAP_CHANNELS - 1];
885
886#ifdef L2CAP_DESIRED_LINK_ROLE
887  l2cb.desire_role = L2CAP_DESIRED_LINK_ROLE;
888#else
889  l2cb.desire_role = HCI_ROLE_SLAVE;
890#endif
891
892  /* Set the default idle timeout */
893  l2cb.idle_timeout = L2CAP_LINK_INACTIVITY_TOUT;
894
895#if defined(L2CAP_INITIAL_TRACE_LEVEL)
896  l2cb.l2cap_trace_level = L2CAP_INITIAL_TRACE_LEVEL;
897#else
898  l2cb.l2cap_trace_level = BT_TRACE_LEVEL_NONE; /* No traces */
899#endif
900
901#if (L2CAP_CONFORMANCE_TESTING == TRUE)
902  /* Conformance testing needs a dynamic response */
903  l2cb.test_info_resp = L2CAP_EXTFEA_SUPPORTED_MASK;
904#endif
905
906/* Number of ACL buffers to use for high priority channel */
907#if (L2CAP_HIGH_PRI_CHAN_QUOTA_IS_CONFIGURABLE == TRUE)
908  l2cb.high_pri_min_xmit_quota = L2CAP_HIGH_PRI_MIN_XMIT_QUOTA;
909#endif
910
911  l2cb.l2c_ble_fixed_chnls_mask = L2CAP_FIXED_CHNL_ATT_BIT |
912                                  L2CAP_FIXED_CHNL_BLE_SIG_BIT |
913                                  L2CAP_FIXED_CHNL_SMP_BIT;
914
915  l2cb.rcv_pending_q = list_new(NULL);
916  CHECK(l2cb.rcv_pending_q != NULL);
917
918  l2cb.receive_hold_timer = alarm_new("l2c.receive_hold_timer");
919}
920
921void l2c_free(void) {
922  list_free(l2cb.rcv_pending_q);
923  l2cb.rcv_pending_q = NULL;
924}
925
926void l2c_receive_hold_timer_timeout(UNUSED_ATTR void* data) {
927  /* Update the timeouts in the hold queue */
928  l2c_process_held_packets(true);
929}
930
931void l2c_ccb_timer_timeout(void* data) {
932  tL2C_CCB* p_ccb = (tL2C_CCB*)data;
933
934  l2c_csm_execute(p_ccb, L2CEVT_TIMEOUT, NULL);
935}
936
937void l2c_fcrb_ack_timer_timeout(void* data) {
938  tL2C_CCB* p_ccb = (tL2C_CCB*)data;
939
940  l2c_csm_execute(p_ccb, L2CEVT_ACK_TIMEOUT, NULL);
941}
942
943void l2c_lcb_timer_timeout(void* data) {
944  tL2C_LCB* p_lcb = (tL2C_LCB*)data;
945
946  l2c_link_timeout(p_lcb);
947}
948
949/*******************************************************************************
950 *
951 * Function         l2c_data_write
952 *
953 * Description      API functions call this function to write data.
954 *
955 * Returns          L2CAP_DW_SUCCESS, if data accepted, else false
956 *                  L2CAP_DW_CONGESTED, if data accepted and the channel is
957 *                                      congested
958 *                  L2CAP_DW_FAILED, if error
959 *
960 ******************************************************************************/
961uint8_t l2c_data_write(uint16_t cid, BT_HDR* p_data, uint16_t flags) {
962  tL2C_CCB* p_ccb;
963
964  /* Find the channel control block. We don't know the link it is on. */
965  p_ccb = l2cu_find_ccb_by_cid(NULL, cid);
966  if (p_ccb == NULL) {
967    L2CAP_TRACE_WARNING("L2CAP - no CCB for L2CA_DataWrite, CID: %d", cid);
968    osi_free(p_data);
969    return (L2CAP_DW_FAILED);
970  }
971
972#ifndef TESTER /* Tester may send any amount of data. otherwise sending \
973                  message                                               \
974                  bigger than mtu size of peer is a violation of protocol */
975  uint16_t mtu;
976
977  if (p_ccb->p_lcb->transport == BT_TRANSPORT_LE)
978    mtu = p_ccb->peer_conn_cfg.mtu;
979  else
980    mtu = p_ccb->peer_cfg.mtu;
981
982  if (p_data->len > mtu) {
983    L2CAP_TRACE_WARNING(
984        "L2CAP - CID: 0x%04x  cannot send message bigger than peer's mtu size: "
985        "len=%u mtu=%u",
986        cid, p_data->len, mtu);
987    osi_free(p_data);
988    return (L2CAP_DW_FAILED);
989  }
990#endif
991
992  /* channel based, packet based flushable or non-flushable */
993  p_data->layer_specific = flags;
994
995  /* If already congested, do not accept any more packets */
996  if (p_ccb->cong_sent) {
997    L2CAP_TRACE_ERROR(
998        "L2CAP - CID: 0x%04x cannot send, already congested  "
999        "xmit_hold_q.count: %u  buff_quota: %u",
1000        p_ccb->local_cid, fixed_queue_length(p_ccb->xmit_hold_q),
1001        p_ccb->buff_quota);
1002
1003    osi_free(p_data);
1004    return (L2CAP_DW_FAILED);
1005  }
1006
1007  l2c_csm_execute(p_ccb, L2CEVT_L2CA_DATA_WRITE, p_data);
1008
1009  if (p_ccb->cong_sent) return (L2CAP_DW_CONGESTED);
1010
1011  return (L2CAP_DW_SUCCESS);
1012}
1013