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//
// Copyright 20 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#include "model/hci/h4_parser.h" // for H4Parser, PacketType, H4Pars...
#include <array>
#include <cstddef> // for size_t
#include <cstdint> // for uint8_t, int32_t
#include <functional> // for function
#include <utility> // for move
#include <vector> // for vector
#include "log.h" // for LOG_ALWAYS_FATAL, LOG_INFO
#include "model/hci/hci_protocol.h" // for PacketReadCallback
namespace rootcanal {
void H4Parser::Reset() {
state_ = HCI_TYPE;
packet_.clear();
bytes_wanted_ = 0;
packet_type_ = 0;
}
size_t H4Parser::HciGetPacketLengthForType(PacketType type,
const uint8_t* preamble) const {
static const size_t
packet_length_offset[static_cast<size_t>(PacketType::ISO) + 1] = {
0,
H4Parser::COMMAND_LENGTH_OFFSET,
H4Parser::ACL_LENGTH_OFFSET,
H4Parser::SCO_LENGTH_OFFSET,
H4Parser::EVENT_LENGTH_OFFSET,
H4Parser::ISO_LENGTH_OFFSET,
};
size_t offset = packet_length_offset[static_cast<size_t>(type)];
size_t size = preamble[offset];
if (type == PacketType::ACL) {
size |= ((size_t)preamble[offset + 1]) << 8u;
}
if (type == PacketType::ISO) {
size |= ((size_t)preamble[offset + 1] & 0x0fu) << 8u;
}
return size;
}
H4Parser::H4Parser(PacketReadCallback command_cb, PacketReadCallback event_cb,
PacketReadCallback acl_cb, PacketReadCallback sco_cb,
PacketReadCallback iso_cb, bool enable_recovery_state)
: command_cb_(std::move(command_cb)),
event_cb_(std::move(event_cb)),
acl_cb_(std::move(acl_cb)),
sco_cb_(std::move(sco_cb)),
iso_cb_(std::move(iso_cb)),
enable_recovery_state_(enable_recovery_state) {}
void H4Parser::OnPacketReady() {
switch (hci_packet_type_) {
case PacketType::COMMAND:
command_cb_(packet_);
break;
case PacketType::ACL:
acl_cb_(packet_);
break;
case PacketType::SCO:
sco_cb_(packet_);
break;
case PacketType::EVENT:
event_cb_(packet_);
break;
case PacketType::ISO:
iso_cb_(packet_);
break;
default:
LOG_ALWAYS_FATAL("Unimplemented packet type %d",
static_cast<int>(hci_packet_type_));
}
// Get ready for the next type byte.
hci_packet_type_ = PacketType::UNKNOWN;
}
size_t H4Parser::BytesRequested() {
switch (state_) {
case HCI_TYPE:
case HCI_RECOVERY:
return 1;
case HCI_PREAMBLE:
case HCI_PAYLOAD:
return bytes_wanted_;
}
}
bool H4Parser::Consume(const uint8_t* buffer, int32_t bytes_read) {
size_t bytes_to_read = BytesRequested();
if (bytes_read <= 0) {
LOG_INFO("remote disconnected, or unhandled error?");
return false;
} else if ((uint32_t)bytes_read > BytesRequested()) {
LOG_ALWAYS_FATAL("More bytes read (%u) than expected (%u)!",
static_cast<int>(bytes_read),
static_cast<int>(bytes_to_read));
}
static const size_t preamble_size[static_cast<size_t>(PacketType::ISO) + 1] =
{
0,
H4Parser::COMMAND_PREAMBLE_SIZE,
H4Parser::ACL_PREAMBLE_SIZE,
H4Parser::SCO_PREAMBLE_SIZE,
H4Parser::EVENT_PREAMBLE_SIZE,
H4Parser::ISO_PREAMBLE_SIZE,
};
switch (state_) {
case HCI_TYPE:
// bytes_read >= 1
packet_type_ = *buffer;
packet_.clear();
break;
case HCI_RECOVERY: {
// Skip all received bytes until the HCI Reset command is received.
// The parser can end up in a bad state when the host is restarted.
const std::array<uint8_t, 4> reset_command{0x01, 0x03, 0x0c, 0x00};
size_t offset = packet_.size();
LOG_WARN("Received byte in recovery state : 0x%x",
static_cast<unsigned>(*buffer));
packet_.push_back(*buffer);
// Last byte does not match expected byte in the sequence.
// Drop all the bytes and start over.
if (packet_[offset] != reset_command[offset]) {
packet_.clear();
// The mismatched byte can also be the first of the correct sequence.
if (*buffer == reset_command[0]) {
packet_.push_back(*buffer);
}
}
// Received full reset command.
if (packet_.size() == reset_command.size()) {
LOG_INFO("Received HCI Reset command, exiting recovery state");
// Pop the Idc from the received packet.
packet_.erase(packet_.begin());
bytes_wanted_ = 0;
}
break;
}
case HCI_PREAMBLE:
case HCI_PAYLOAD:
packet_.insert(packet_.end(), buffer, buffer + bytes_read);
bytes_wanted_ -= bytes_read;
break;
}
switch (state_) {
case HCI_TYPE:
hci_packet_type_ = static_cast<PacketType>(packet_type_);
if (hci_packet_type_ != PacketType::ACL &&
hci_packet_type_ != PacketType::SCO &&
hci_packet_type_ != PacketType::COMMAND &&
hci_packet_type_ != PacketType::EVENT &&
hci_packet_type_ != PacketType::ISO) {
if (!enable_recovery_state_) {
LOG_ALWAYS_FATAL("Received invalid packet type 0x%x",
static_cast<unsigned>(packet_type_));
}
LOG_ERROR("Received invalid packet type 0x%x, entering recovery state",
static_cast<unsigned>(packet_type_));
state_ = HCI_RECOVERY;
hci_packet_type_ = PacketType::COMMAND;
bytes_wanted_ = 1;
} else {
state_ = HCI_PREAMBLE;
bytes_wanted_ = preamble_size[static_cast<size_t>(hci_packet_type_)];
}
break;
case HCI_PREAMBLE:
if (bytes_wanted_ == 0) {
size_t payload_size =
HciGetPacketLengthForType(hci_packet_type_, packet_.data());
if (payload_size == 0) {
OnPacketReady();
state_ = HCI_TYPE;
} else {
bytes_wanted_ = payload_size;
state_ = HCI_PAYLOAD;
}
}
break;
case HCI_RECOVERY:
case HCI_PAYLOAD:
if (bytes_wanted_ == 0) {
OnPacketReady();
state_ = HCI_TYPE;
}
break;
}
return true;
}
} // namespace rootcanal
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