132 lines
4.2 KiB
C++
132 lines
4.2 KiB
C++
//
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// Copyright 2021 The Android Open Source Project
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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#pragma once
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#include <stddef.h> // for size_t
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#include <cstdint> // for uint8_t, int32_t
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#include <functional> // for function
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#include <ostream> // for operator<<, ostream
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#include <vector> // for vector
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#include "model/hci/h4.h" // for PacketType
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#include "model/hci/hci_protocol.h" // for PacketReadCallback
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namespace rootcanal {
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using HciPacketReadyCallback = std::function<void(void)>;
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using ClientDisconnectCallback = std::function<void()>;
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// An H4 Parser can parse H4 Packets and will invoke the proper callback
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// once a packet has been parsed.
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//
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// You use it as follows:
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//
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// H4Parser h4(....);
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// size_t nr_bytes = h4.BytesRequested();
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// std::vector fill_this_vector_with_at_most_nr_bytes(nr_bytes);
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// h4.Consume(fill_this_vector_with_at_most_nr_bytes.data(), nr_bytes.size());
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//
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// The parser will invoke the proper callbacks once a packet has been parsed.
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// The parser keeps internal state and is not thread safe.
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class H4Parser {
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public:
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enum State { HCI_TYPE, HCI_PREAMBLE, HCI_PAYLOAD, HCI_RECOVERY };
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H4Parser(PacketReadCallback command_cb, PacketReadCallback event_cb,
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PacketReadCallback acl_cb, PacketReadCallback sco_cb,
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PacketReadCallback iso_cb, bool enable_recovery_state = false);
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// Consumes the given number of bytes, returns true on success.
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bool Consume(const uint8_t* buffer, int32_t bytes);
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// The maximum number of bytes the parser can consume in the current state.
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size_t BytesRequested();
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// Resets the parser to the empty, initial state.
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void Reset();
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State CurrentState() { return state_; };
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void EnableRecovery() { enable_recovery_state_ = true; }
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void DisableRecovery() { enable_recovery_state_ = false; }
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private:
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void OnPacketReady();
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// 2 bytes for opcode, 1 byte for parameter length (Volume 2, Part E, 5.4.1)
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static constexpr size_t COMMAND_PREAMBLE_SIZE = 3;
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static constexpr size_t COMMAND_LENGTH_OFFSET = 2;
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// 2 bytes for handle, 2 bytes for data length (Volume 2, Part E, 5.4.2)
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static constexpr size_t ACL_PREAMBLE_SIZE = 4;
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static constexpr size_t ACL_LENGTH_OFFSET = 2;
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// 2 bytes for handle, 1 byte for data length (Volume 2, Part E, 5.4.3)
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static constexpr size_t SCO_PREAMBLE_SIZE = 3;
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static constexpr size_t SCO_LENGTH_OFFSET = 2;
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// 1 byte for event code, 1 byte for parameter length (Volume 2, Part
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// E, 5.4.4)
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static constexpr size_t EVENT_PREAMBLE_SIZE = 2;
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static constexpr size_t EVENT_LENGTH_OFFSET = 1;
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// 2 bytes for handle and flags, 12 bits for length (Volume 2, Part E, 5.4.5)
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static constexpr size_t ISO_PREAMBLE_SIZE = 4;
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static constexpr size_t ISO_LENGTH_OFFSET = 2;
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PacketReadCallback command_cb_;
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PacketReadCallback event_cb_;
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PacketReadCallback acl_cb_;
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PacketReadCallback sco_cb_;
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PacketReadCallback iso_cb_;
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size_t HciGetPacketLengthForType(PacketType type,
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const uint8_t* preamble) const;
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PacketType hci_packet_type_{PacketType::UNKNOWN};
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State state_{HCI_TYPE};
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uint8_t packet_type_{};
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std::vector<uint8_t> packet_;
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size_t bytes_wanted_{0};
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bool enable_recovery_state_{false};
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};
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inline std::ostream& operator<<(std::ostream& os,
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H4Parser::State const& state_) {
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switch (state_) {
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case H4Parser::State::HCI_TYPE:
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os << "HCI_TYPE";
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break;
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case H4Parser::State::HCI_PREAMBLE:
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os << "HCI_PREAMBLE";
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break;
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case H4Parser::State::HCI_PAYLOAD:
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os << "HCI_PAYLOAD";
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break;
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case H4Parser::State::HCI_RECOVERY:
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os << "HCI_RECOVERY";
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break;
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default:
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os << "unknown state " << static_cast<int>(state_);
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break;
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}
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return os;
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}
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} // namespace rootcanal
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