mirror of
https://github.com/kidfromjupiter/nearby.git
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365 lines
11 KiB
C++
365 lines
11 KiB
C++
// Copyright 2024 Google LLC
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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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// https://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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#include "internal/platform/implementation/linux/ble_l2cap_socket.h"
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#include <bluetooth/bluetooth.h>
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#include <bluetooth/l2cap.h>
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#include <sys/poll.h>
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#include <sys/socket.h>
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#include <unistd.h>
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#include <cerrno>
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#include <cstring>
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#include <bluetooth/bluetooth.h>
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#include "absl/strings/escaping.h"
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#include "absl/strings/string_view.h"
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#include "internal/platform/byte_array.h"
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#include "internal/platform/exception.h"
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#include "internal/platform/logging.h"
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#include <sys/ioctl.h>
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#include "bluetooth_classic_socket.h"
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namespace nearby {
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namespace linux {
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namespace {
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constexpr size_t kLogMaxBytes = 64;
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constexpr size_t kDefaultBleL2capMtu = 23;
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size_t GetSocketMtu(int fd, int option_name) {
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uint16_t mtu = 0;
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socklen_t len = sizeof(mtu);
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if (getsockopt(fd, SOL_BLUETOOTH, option_name, &mtu, &len) == 0 &&
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mtu > 0) {
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return static_cast<size_t>(mtu);
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}
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return 0;
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}
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std::string HexPreview(const char* data, size_t size) {
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size_t count = std::min(size, kLogMaxBytes);
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std::string hex =
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absl::BytesToHexString(absl::string_view(data, count));
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if (size > count) {
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hex.append("...");
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}
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return hex;
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}
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size_t GetL2capOutputMtu(int fd) {
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struct l2cap_options opts;
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size_t mtu = GetSocketMtu(fd, BT_SNDMTU);
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if (mtu > 0) {
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return mtu;
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}
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return kDefaultBleL2capMtu;
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}
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Exception PollSocket(int fd, short event) {
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struct pollfd fds[1];
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fds[0].fd = fd;
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fds[0].events = event;
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while (true) {
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int ret = poll(fds, 1, -1);
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if (ret < 0) {
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if (errno == EINTR) continue;
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LOG(ERROR) << "Error polling L2CAP socket: " << std::strerror(errno);
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return {Exception::kIo};
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}
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if ((fds[0].revents & event) != 0) {
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return {Exception::kSuccess};
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}
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if ((fds[0].revents & POLLHUP) != 0) {
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LOG(ERROR) << "L2CAP socket disconnected";
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return {Exception::kIo};
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}
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if ((fds[0].revents & (POLLERR | POLLNVAL)) != 0) {
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LOG(ERROR) << "Error occurred on L2CAP socket";
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return {Exception::kIo};
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}
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}
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}
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} // namespace
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BleL2capInputStream::BleL2capInputStream(int fd) : fd_(fd) {}
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BleL2capInputStream::~BleL2capInputStream() { Close(); }
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static size_t GetBleCocRcvMtu(int fd) {
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// Prefer BT_RCVMTU for LE CoC, but fall back to L2CAP_OPTIONS if needed.
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uint16_t mtu = 0;
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socklen_t len = sizeof(mtu);
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if (getsockopt(fd, SOL_BLUETOOTH, BT_RCVMTU, &mtu, &len) == 0 && mtu > 0)
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return mtu;
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// Fallback ONLY (avoid 23 unless you're sure; 23 causes truncation if peer sends bigger SDUs).
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return 512;
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}
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static size_t NextPacketSize(int fd) {
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int pending = 0;
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if (ioctl(fd, FIONREAD, &pending) == 0 && pending > 0) {
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return static_cast<size_t>(pending);
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}
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return 0; // unknown
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}
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ExceptionOr<ByteArray> BleL2capInputStream::Read(std::int64_t size) {
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int fd = fd_.load();
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if (fd < 0) return Exception{Exception::kIo};
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auto poller = Poller::CreateInputPoller(fd);
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// Wait for readability
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while (true) {
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if (fd_.load() != fd) return {Exception::kIo};
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auto result = poller.Ready();
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if (result.Raised()) return result;
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if (fd_.load() != fd) return {Exception::kIo};
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// Peek the next message length without consuming it.
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// For seqpacket/dgram, MSG_TRUNC makes recv() return the *full* message length
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// even if the buffer is smaller.
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ssize_t msg_len = ::recv(fd, nullptr, 0, MSG_PEEK | MSG_TRUNC);
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if (msg_len < 0) {
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if (errno == EINTR) continue;
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if (errno == EAGAIN || errno == EWOULDBLOCK) continue;
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if (errno == EBADF) {
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LOG(INFO) << __func__ << ": socket was closed during read";
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return {Exception::kIo};
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}
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LOG(ERROR) << __func__ << ": error peeking message length: "
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<< std::strerror(errno);
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return {Exception::kIo};
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}
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if (msg_len == 0) {
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LOG(INFO) << __func__ << ": socket closed (EOF)";
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return {Exception::kIo};
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}
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// Decide how much we will actually read/return.
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// If caller asked for 'size', cap to that.
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size_t want = static_cast<size_t>(msg_len);
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size_t cap = static_cast<size_t>(size);
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size_t to_read = std::min(want, cap);
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std::string buffer;
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buffer.resize(to_read);
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// Now read/consume the message. If the message is larger than to_read,
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// the remainder will be discarded by the kernel for seqpacket/dgram.
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// We can detect that and treat it as an error (or choose a different policy).
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if (fd_.load() != fd) return {Exception::kIo};
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ssize_t n = ::recv(fd, buffer.data(), to_read, 0);
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if (n < 0) {
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if (errno == EINTR) continue;
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if (errno == EAGAIN || errno == EWOULDBLOCK) continue;
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if (errno == EBADF) {
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LOG(INFO) << __func__ << ": socket was closed during read";
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return {Exception::kIo};
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}
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LOG(ERROR) << __func__ << ": error reading data on bluetooth socket: "
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<< std::strerror(errno);
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return {Exception::kIo};
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}
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if (n == 0) {
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LOG(INFO) << __func__ << ": socket closed (EOF)";
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return {Exception::kIo};
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}
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buffer.resize(static_cast<size_t>(n));
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// Detect truncation: if msg_len > size, we truncated/discarded remainder.
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if (want > cap) {
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LOG(ERROR) << __func__
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<< ": incoming packet (" << want
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<< " bytes) exceeds requested size (" << cap
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<< "). Packet truncated.";
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return {Exception::kIo};
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}
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return ExceptionOr{ByteArray(std::move(buffer))};
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}
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}
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Exception BleL2capInputStream::Close() {
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int fd = fd_.exchange(-1);
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if (fd < 0) return {Exception::kSuccess}; // Already closed
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::shutdown(fd, SHUT_RDWR);
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return {Exception::kSuccess};
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}
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BleL2capOutputStream::BleL2capOutputStream(int fd) : fd_(fd) {}
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BleL2capOutputStream::~BleL2capOutputStream() { Close(); }
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Exception BleL2capOutputStream::Write(const ByteArray& data) {
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int fd = fd_.load();
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if (fd < 0) return Exception{Exception::kIo};
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auto poller = Poller::CreateOutputPoller(fd);
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size_t total_wrote = 0;
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if (data.Empty()) {
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return {Exception::kSuccess};
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}
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size_t max_chunk_size = GetL2capOutputMtu(fd);
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if (max_chunk_size == 0) {
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max_chunk_size = kDefaultBleL2capMtu;
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}
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LOG(INFO) << "BleL2capOutputStream::Write bytes=" << data.size()
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<< " mtu=" << max_chunk_size << " data=0x"
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<< HexPreview(data.data(), data.size());
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while (total_wrote < data.size()) {
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if (fd_.load() != fd) return {Exception::kIo};
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auto result = poller.Ready(); // should wait for POLLOUT/EPOLLOUT
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if (result.Raised()) return result;
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if (fd_.load() != fd) return {Exception::kIo};
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const char *buf = data.data();
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size_t remaining = data.size() - total_wrote;
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size_t to_write = remaining;
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{
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// For SEQPACKET/DGRAM, one send() == one packet.
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// Cap to discovered “MTU-like” limit to avoid EMSGSIZE.
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absl::MutexLock lock(&fd_mutex_);
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to_write = std::min(to_write, max_chunk_size);
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}
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// Prefer send() to avoid SIGPIPE (MSG_NOSIGNAL is Linux).
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ssize_t wrote = ::send(fd,
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buf + total_wrote,
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to_write,
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#ifdef MSG_NOSIGNAL
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MSG_NOSIGNAL
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#else
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0
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#endif
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);
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// If send() isn’t appropriate in your environment, you can swap back to write().
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// ssize_t wrote = ::write(fd_.get(), buf + total_wrote, to_write);
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if (wrote < 0) {
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if (errno == EINTR) continue;
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if (errno == EAGAIN || errno == EWOULDBLOCK) continue;
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if (errno == EMSGSIZE) {
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// Our packet is too large; shrink max_chunk_ and retry.
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{
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absl::MutexLock lock(&fd_mutex_);
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if (max_chunk_size > 1) {
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max_chunk_size = std::max<size_t>(1, max_chunk_size / 2);
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LOG(INFO) << __func__ << ": EMSGSIZE; reducing max_chunk_ to "
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<< max_chunk_size;
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continue; // retry with smaller chunk
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}
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}
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LOG(ERROR) << __func__ << ": EMSGSIZE even at 1 byte";
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return {Exception::kIo};
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}
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if (errno == EBADF || errno == EPIPE) {
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LOG(INFO) << __func__ << ": socket was closed during write";
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return {Exception::kIo};
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}
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LOG(ERROR) << __func__
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<< ": error writing data on bluetooth socket: "
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<< std::strerror(errno);
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return {Exception::kIo};
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}
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if (wrote == 0) {
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// For sockets, 0 usually means peer closed.
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LOG(INFO) << __func__ << ": peer closed during write";
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return {Exception::kIo};
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}
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total_wrote += static_cast<size_t>(wrote);
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}
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return {Exception::kSuccess};
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}
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Exception BleL2capOutputStream::Close() {
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int fd = fd_.exchange(-1);
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if (fd < 0) return {Exception::kSuccess}; // Already closed
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::shutdown(fd, SHUT_RDWR);
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return {Exception::kSuccess};
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}
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BleL2capSocket::BleL2capSocket(int fd,
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api::ble_v2::BlePeripheral::UniqueId peripheral_id)
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: peripheral_id_(peripheral_id),
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input_stream_(std::make_unique<BleL2capInputStream>(fd)),
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output_stream_(std::make_unique<BleL2capOutputStream>(fd))
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{
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LOG(INFO) << "fd_ " << fd;
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LOG(INFO) << "input_stream_ :" << input_stream_.get();
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LOG(INFO) << "output_stream_ :" << output_stream_.get();
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struct l2cap_options opts;
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size_t snd_mtu = GetSocketMtu(fd, BT_SNDMTU);
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size_t rcv_mtu = GetSocketMtu(fd, BT_RCVMTU);
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LOG(INFO) << "BleL2capSocket MTU fallback snd_mtu=" << snd_mtu
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<< " rcv_mtu=" << rcv_mtu;
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}
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BleL2capSocket::~BleL2capSocket() { Close(); }
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Exception BleL2capSocket::Close() {
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absl::MutexLock lock(&mutex_);
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if (closed_) {
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return {Exception::kSuccess};
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}
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DoClose();
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return {Exception::kSuccess};
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}
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void BleL2capSocket::DoClose() {
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closed_ = true;
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if (input_stream_) {
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input_stream_->Close();
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}
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if (output_stream_) {
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output_stream_->Close();
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}
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if (close_notifier_) {
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auto notifier = std::move(close_notifier_);
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mutex_.Unlock();
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notifier();
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mutex_.Lock();
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}
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}
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void BleL2capSocket::SetCloseNotifier(absl::AnyInvocable<void()> notifier) {
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absl::MutexLock lock(&mutex_);
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close_notifier_ = std::move(notifier);
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}
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bool BleL2capSocket::IsClosed() const {
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absl::MutexLock lock(&mutex_);
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return closed_;
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}
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} // namespace linux
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} // namespace nearby
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