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 #include "l2cap/internal/le_credit_based_channel_data_controller.h"
18
19 #include <bluetooth/log.h>
20
21 #include "l2cap/l2cap_packets.h"
22 #include "l2cap/le/internal/link.h"
23 #include "packet/fragmenting_inserter.h"
24 #include "packet/raw_builder.h"
25
26 namespace bluetooth {
27 namespace l2cap {
28 namespace internal {
29
LeCreditBasedDataController(ILink * link,Cid cid,Cid remote_cid,UpperQueueDownEnd * channel_queue_end,os::Handler * handler,Scheduler * scheduler)30 LeCreditBasedDataController::LeCreditBasedDataController(ILink* link, Cid cid, Cid remote_cid,
31 UpperQueueDownEnd* channel_queue_end, os::Handler* handler,
32 Scheduler* scheduler)
33 : cid_(cid), remote_cid_(remote_cid), enqueue_buffer_(channel_queue_end), handler_(handler), scheduler_(scheduler),
34 link_(link) {}
35
OnSdu(std::unique_ptr<packet::BasePacketBuilder> sdu)36 void LeCreditBasedDataController::OnSdu(std::unique_ptr<packet::BasePacketBuilder> sdu) {
37 auto sdu_size = sdu->size();
38 if (sdu_size == 0) {
39 log::warn("Received empty SDU");
40 return;
41 }
42 if (sdu_size > mtu_) {
43 log::warn("Received sdu_size {} > mtu {}", static_cast<int>(sdu_size), mtu_);
44 }
45 std::vector<std::unique_ptr<packet::RawBuilder>> segments;
46 // TODO: We don't need to waste 2 bytes for continuation segment.
47 packet::FragmentingInserter fragmenting_inserter(mps_ - 2, std::back_insert_iterator(segments));
48 sdu->Serialize(fragmenting_inserter);
49 fragmenting_inserter.finalize();
50 std::unique_ptr<BasicFrameBuilder> builder;
51 builder = FirstLeInformationFrameBuilder::Create(remote_cid_, sdu_size, std::move(segments[0]));
52 pdu_queue_.emplace(std::move(builder));
53 for (size_t i = 1; i < segments.size(); i++) {
54 builder = BasicFrameBuilder::Create(remote_cid_, std::move(segments[i]));
55 pdu_queue_.emplace(std::move(builder));
56 }
57 if (credits_ >= segments.size()) {
58 scheduler_->OnPacketsReady(cid_, segments.size());
59 credits_ -= segments.size();
60 } else if (credits_ > 0) {
61 scheduler_->OnPacketsReady(cid_, credits_);
62 pending_frames_count_ += (segments.size() - credits_);
63 credits_ = 0;
64 } else {
65 pending_frames_count_ += segments.size();
66 }
67 }
68
OnPdu(packet::PacketView<true> pdu)69 void LeCreditBasedDataController::OnPdu(packet::PacketView<true> pdu) {
70 auto basic_frame_view = BasicFrameView::Create(pdu);
71 if (!basic_frame_view.IsValid()) {
72 log::warn("Received invalid frame");
73 return;
74 }
75 if (basic_frame_view.size() > mps_) {
76 log::warn(
77 "Received frame size {} > mps {}, dropping the packet",
78 static_cast<int>(basic_frame_view.size()),
79 mps_);
80 return;
81 }
82 if (remaining_sdu_continuation_packet_size_ == 0) {
83 auto start_frame_view = FirstLeInformationFrameView::Create(basic_frame_view);
84 if (!start_frame_view.IsValid()) {
85 log::warn("Received invalid frame");
86 return;
87 }
88 auto payload = start_frame_view.GetPayload();
89 auto sdu_size = start_frame_view.GetL2capSduLength();
90 remaining_sdu_continuation_packet_size_ = sdu_size - payload.size();
91 reassembly_stage_ = payload;
92 } else {
93 auto payload = basic_frame_view.GetPayload();
94 remaining_sdu_continuation_packet_size_ -= payload.size();
95 reassembly_stage_.AppendPacketView(payload);
96 }
97 if (remaining_sdu_continuation_packet_size_ == 0) {
98 enqueue_buffer_.Enqueue(std::make_unique<PacketView<kLittleEndian>>(reassembly_stage_), handler_);
99 } else if (remaining_sdu_continuation_packet_size_ < 0 || reassembly_stage_.size() > mtu_) {
100 log::warn("Received larger SDU size than expected");
101 reassembly_stage_ = PacketViewForReassembly(PacketView<kLittleEndian>(std::make_shared<std::vector<uint8_t>>()));
102 remaining_sdu_continuation_packet_size_ = 0;
103 link_->SendDisconnectionRequest(cid_, remote_cid_);
104 }
105 // TODO: Improve the logic by sending credit only after user dequeued the SDU
106 link_->SendLeCredit(cid_, 1);
107 }
108
GetNextPacket()109 std::unique_ptr<packet::BasePacketBuilder> LeCreditBasedDataController::GetNextPacket() {
110 log::assert_that(!pdu_queue_.empty(), "assert failed: !pdu_queue_.empty()");
111 auto next = std::move(pdu_queue_.front());
112 pdu_queue_.pop();
113 return next;
114 }
115
SetMtu(Mtu mtu)116 void LeCreditBasedDataController::SetMtu(Mtu mtu) {
117 mtu_ = mtu;
118 }
119
SetMps(uint16_t mps)120 void LeCreditBasedDataController::SetMps(uint16_t mps) {
121 mps_ = mps;
122 }
123
OnCredit(uint16_t credits)124 void LeCreditBasedDataController::OnCredit(uint16_t credits) {
125 int total_credits = credits_ + credits;
126 if (total_credits > 0xffff) {
127 link_->SendDisconnectionRequest(cid_, remote_cid_);
128 }
129 credits_ = total_credits;
130 if (pending_frames_count_ > 0 && credits_ >= pending_frames_count_) {
131 scheduler_->OnPacketsReady(cid_, pending_frames_count_);
132 pending_frames_count_ = 0;
133 credits_ -= pending_frames_count_;
134 } else if (pending_frames_count_ > 0) {
135 scheduler_->OnPacketsReady(cid_, credits_);
136 pending_frames_count_ -= credits_;
137 credits_ = 0;
138 }
139 }
140
141 } // namespace internal
142 } // namespace l2cap
143 } // namespace bluetooth
144