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