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/*
* Copyright (C) 2020 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 "tcp_client.h"
#include "constants.h"
#include <android-base/errors.h>
#include <android-base/logging.h>
#include <android-base/parseint.h>
#include <android-base/properties.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
static constexpr int kDefaultPort = 5554;
static constexpr int kProtocolVersion = 1;
static constexpr int kHandshakeTimeoutMs = 2000;
static constexpr size_t kHandshakeLength = 4;
// Extract the big-endian 8-byte message length into a 64-bit number.
static uint64_t ExtractMessageLength(const void* buffer) {
uint64_t ret = 0;
for (int i = 0; i < 8; ++i) {
ret |= uint64_t{reinterpret_cast<const uint8_t*>(buffer)[i]} << (56 - i * 8);
}
return ret;
}
// Encode the 64-bit number into a big-endian 8-byte message length.
static void EncodeMessageLength(uint64_t length, void* buffer) {
for (int i = 0; i < 8; ++i) {
reinterpret_cast<uint8_t*>(buffer)[i] = length >> (56 - i * 8);
}
}
ClientTcpTransport::ClientTcpTransport() {
service_ = Socket::NewServer(Socket::Protocol::kTcp, kDefaultPort);
// A workaround to notify recovery to continue its work.
android::base::SetProperty("sys.usb.ffs.ready", "1");
}
ssize_t ClientTcpTransport::Read(void* data, size_t len) {
if (len > SSIZE_MAX) {
return -1;
}
size_t total_read = 0;
do {
// Read a new message
while (message_bytes_left_ == 0) {
if (socket_ == nullptr) {
ListenFastbootSocket();
}
char buffer[8];
if (socket_->ReceiveAll(buffer, 8, 0) == 8) {
message_bytes_left_ = ExtractMessageLength(buffer);
} else {
// If connection is closed by host, Receive will return 0 immediately.
socket_.reset(nullptr);
// In DATA phase, return error.
if (downloading_) {
return -1;
}
}
}
size_t read_length = len - total_read;
if (read_length > message_bytes_left_) {
read_length = message_bytes_left_;
}
ssize_t bytes_read =
socket_->ReceiveAll(reinterpret_cast<char*>(data) + total_read, read_length, 0);
if (bytes_read == -1) {
socket_.reset(nullptr);
return -1;
} else {
message_bytes_left_ -= bytes_read;
total_read += bytes_read;
}
// There are more than one DATA phases if the downloading buffer is too
// large, like a very big system image. All of data phases should be
// received until the whole buffer is filled in that case.
} while (downloading_ && total_read < len);
return total_read;
}
ssize_t ClientTcpTransport::Write(const void* data, size_t len) {
if (socket_ == nullptr || len > SSIZE_MAX) {
return -1;
}
// Use multi-buffer writes for better performance.
char header[8];
EncodeMessageLength(len, header);
if (!socket_->Send(std::vector<cutils_socket_buffer_t>{{header, 8}, {data, len}})) {
socket_.reset(nullptr);
return -1;
}
// In DATA phase
if (android::base::StartsWith(reinterpret_cast<const char*>(data), RESPONSE_DATA)) {
downloading_ = true;
} else {
downloading_ = false;
}
return len;
}
int ClientTcpTransport::Close() {
if (socket_ == nullptr) {
return -1;
}
socket_.reset(nullptr);
return 0;
}
int ClientTcpTransport::Reset() {
return Close();
}
void ClientTcpTransport::ListenFastbootSocket() {
while (true) {
socket_ = service_->Accept();
// Handshake
char buffer[kHandshakeLength + 1];
buffer[kHandshakeLength] = '\0';
if (socket_->ReceiveAll(buffer, kHandshakeLength, kHandshakeTimeoutMs) !=
kHandshakeLength) {
PLOG(ERROR) << "No Handshake message received";
socket_.reset(nullptr);
continue;
}
if (memcmp(buffer, "FB", 2) != 0) {
PLOG(ERROR) << "Unrecognized initialization message";
socket_.reset(nullptr);
continue;
}
int version = 0;
if (!android::base::ParseInt(buffer + 2, &version) || version < kProtocolVersion) {
LOG(ERROR) << "Unknown TCP protocol version " << buffer + 2
<< ", our version: " << kProtocolVersion;
socket_.reset(nullptr);
continue;
}
std::string handshake_message(android::base::StringPrintf("FB%02d", kProtocolVersion));
if (!socket_->Send(handshake_message.c_str(), kHandshakeLength)) {
PLOG(ERROR) << "Failed to send initialization message";
socket_.reset(nullptr);
continue;
}
break;
}
}
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