1 /*
2  * Copyright 2019 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #pragma once
18 
19 #include <unordered_map>
20 #include <unordered_set>
21 
22 #include "hci/acl_manager.h"
23 #include "l2cap/cid.h"
24 #include "l2cap/internal/ilink.h"
25 #include "l2cap/psm.h"
26 #include "l2cap/security_policy.h"
27 #include "os/handler.h"
28 #include "os/log.h"
29 
30 namespace bluetooth {
31 namespace l2cap {
32 namespace internal {
33 
34 class DynamicChannelImpl;
35 
36 // Helper class for keeping channels in a Link. It allocates and frees Channel object, and supports querying whether a
37 // channel is in use
38 class DynamicChannelAllocator {
39  public:
40   DynamicChannelAllocator(l2cap::internal::ILink* link, os::Handler* l2cap_handler)
41       : link_(link), l2cap_handler_(l2cap_handler) {
42     ASSERT(link_ != nullptr);
43     ASSERT(l2cap_handler_ != nullptr);
44   }
45 
46   // Allocates a channel. If psm is used, OR the remote cid already exists, return nullptr.
47   // NOTE: The returned DynamicChannelImpl object is still owned by the channel allocator, NOT the client.
48   std::shared_ptr<DynamicChannelImpl> AllocateChannel(Psm psm, Cid remote_cid, SecurityPolicy security_policy);
49 
50   std::shared_ptr<DynamicChannelImpl> AllocateReservedChannel(Cid reserved_cid, Psm psm, Cid remote_cid,
51                                                               SecurityPolicy security_policy);
52 
53   // Gives an unused Cid to be used for opening a channel. If a channel is used, call AllocateReservedChannel. If no
54   // longer needed, use FreeChannel.
55   Cid ReserveChannel();
56 
57   // Frees a channel. If psm doesn't exist, it will crash
58   void FreeChannel(Cid cid);
59 
60   bool IsPsmUsed(Psm psm) const;
61 
62   std::shared_ptr<DynamicChannelImpl> FindChannelByCid(Cid cid);
63   std::shared_ptr<DynamicChannelImpl> FindChannelByRemoteCid(Cid cid);
64 
65   // Returns number of open, but not reserved channels
66   size_t NumberOfChannels() const;
67 
68   void OnAclDisconnected(hci::ErrorCode hci_status);
69 
70  private:
71   l2cap::internal::ILink* link_;
72   os::Handler* l2cap_handler_;
73   std::unordered_set<Cid> used_cid_;
74   std::unordered_map<Cid, std::shared_ptr<DynamicChannelImpl>> channels_;
75   std::unordered_set<Cid> used_remote_cid_;
76 };
77 
78 }  // namespace internal
79 }  // namespace l2cap
80 }  // namespace bluetooth
81