bluetooth: Add support for linux bluetooth raw hci sockets

The implementation is imported from
packages/modules/Bluetooth/system/vendor_libs/linux/interface
with modifications to modernize the code.

The default bluetooth HAL implementation now jointly uses
the serial implementation and the bluetooth socket
implementation.

Bug: 205758693
Test: VtsHalBluetoothTargetTest
Change-Id: I791fd406e56a0144e1117cb6f8e27ec71b48a192

1 files changed, 296 insertions, 0 deletions

diff --git a/bluetooth/aidl/default/net_bluetooth_mgmt.cpp b/bluetooth/aidl/default/net_bluetooth_mgmt.cpp
new file mode 100644
index 0000000000..937cd57432
--- /dev/null
+++ b/bluetooth/aidl/default/net_bluetooth_mgmt.cpp
@@ -0,0 +1,296 @@
+/*
+ * Copyright 2022 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.
+ */
+
+#define LOG_TAG "android.hardware.bluetooth.service.default"
+
+#include "net_bluetooth_mgmt.h"
+
+#include <fcntl.h>
+#include <log/log.h>
+#include <poll.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+#include <cerrno>
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+
+// Definitions imported from <linux/net/bluetooth/bluetooth.h>
+#define BTPROTO_HCI 1
+
+// Definitions imported from <linux/net/bluetooth/hci_sock.h>
+#define HCI_CHANNEL_USER 1
+#define HCI_CHANNEL_CONTROL 3
+#define HCI_DEV_NONE 0xffff
+
+struct sockaddr_hci {
+  sa_family_t hci_family;
+  unsigned short hci_dev;
+  unsigned short hci_channel;
+};
+
+// Definitions imported from <linux/net/bluetooth/mgmt.h>
+#define MGMT_OP_READ_INDEX_LIST 0x0003
+#define MGMT_EV_INDEX_ADDED 0x0004
+#define MGMT_EV_CMD_COMPLETE 0x0001
+#define MGMT_PKT_SIZE_MAX 1024
+#define MGMT_INDEX_NONE 0xFFFF
+
+struct mgmt_pkt {
+  uint16_t opcode;
+  uint16_t index;
+  uint16_t len;
+  uint8_t data[MGMT_PKT_SIZE_MAX];
+} __attribute__((packed));
+
+struct mgmt_ev_read_index_list {
+  uint16_t opcode;
+  uint8_t status;
+  uint16_t num_controllers;
+  uint16_t index[];
+} __attribute__((packed));
+
+// Definitions imported from <linux/rfkill.h>
+#define RFKILL_STATE_SOFT_BLOCKED 0
+#define RFKILL_STATE_UNBLOCKED 1
+#define RFKILL_STATE_HARD_BLOCKED 2
+
+#define RFKILL_TYPE_BLUETOOTH 2
+
+#define RFKILL_OP_ADD 0
+#define RFKILL_OP_CHANGE 2
+
+struct rfkill_event {
+  uint32_t idx;
+  uint8_t type;
+  uint8_t op;
+  uint8_t soft;
+  uint8_t hard;
+} __attribute__((packed));
+
+namespace aidl::android::hardware::bluetooth::impl {
+
+// Wait indefinitely for the selected HCI interface to be enabled in the
+// bluetooth driver.
+int NetBluetoothMgmt::waitHciDev(int hci_interface) {
+  ALOGI("waiting for hci interface %d", hci_interface);
+
+  int ret = -1;
+  struct mgmt_pkt cmd;
+  struct pollfd pollfd;
+  struct sockaddr_hci hci_addr = {
+      .hci_family = AF_BLUETOOTH,
+      .hci_dev = HCI_DEV_NONE,
+      .hci_channel = HCI_CHANNEL_CONTROL,
+  };
+
+  // Open and bind a socket to the bluetooth control interface in the
+  // kernel driver, used to send control commands and receive control
+  // events.
+  int fd = socket(PF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
+  if (fd < 0) {
+    ALOGE("unable to open raw bluetooth socket: %s", strerror(errno));
+    return -1;
+  }
+
+  if (bind(fd, (struct sockaddr*)&hci_addr, sizeof(hci_addr)) < 0) {
+    ALOGE("unable to bind bluetooth control channel: %s", strerror(errno));
+    goto end;
+  }
+
+  // Send the control command [Read Index List].
+  cmd = {
+      .opcode = MGMT_OP_READ_INDEX_LIST,
+      .index = MGMT_INDEX_NONE,
+      .len = 0,
+  };
+
+  if (write(fd, &cmd, 6) != 6) {
+    ALOGE("error writing mgmt command: %s", strerror(errno));
+    goto end;
+  }
+
+  // Poll the control socket waiting for the command response,
+  // and subsequent [Index Added] events. The loops continue without
+  // timeout until the selected hci interface is detected.
+  pollfd = {.fd = fd, .events = POLLIN};
+
+  for (;;) {
+    ret = poll(&pollfd, 1, -1);
+
+    // Poll interrupted, try again.
+    if (ret == -1 && (errno == EINTR || errno == EAGAIN)) {
+      continue;
+    }
+
+    // Poll failure, abandon.
+    if (ret == -1) {
+      ALOGE("poll error: %s", strerror(errno));
+      break;
+    }
+
+    // Spurious wakeup, try again.
+    if (ret == 0 || (pollfd.revents & POLLIN) == 0) {
+      continue;
+    }
+
+    // Read the next control event.
+    struct mgmt_pkt ev {};
+    ret = read(fd, &ev, sizeof(ev));
+    if (ret < 0) {
+      ALOGE("error reading mgmt event: %s", strerror(errno));
+      goto end;
+    }
+
+    // Received [Read Index List] command response.
+    if (ev.opcode == MGMT_EV_CMD_COMPLETE) {
+      struct mgmt_ev_read_index_list* data =
+          (struct mgmt_ev_read_index_list*)ev.data;
+
+      for (int i = 0; i < data->num_controllers; i++) {
+        if (data->index[i] == hci_interface) {
+          ALOGI("hci interface %d found", hci_interface);
+          ret = 0;
+          goto end;
+        }
+      }
+    }
+
+    // Received [Index Added] event.
+    if (ev.opcode == MGMT_EV_INDEX_ADDED && ev.index == hci_interface) {
+      ALOGI("hci interface %d added", hci_interface);
+      ret = 0;
+      goto end;
+    }
+  }
+
+end:
+  ::close(fd);
+  return ret;
+}
+
+int NetBluetoothMgmt::openRfkill() {
+  int fd = open("/dev/rfkill", O_RDWR);
+  if (fd < 0) {
+    ALOGE("unable to open /dev/rfkill: %s", strerror(errno));
+    return -1;
+  }
+
+  if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) {
+    ALOGE("unable to set rfkill control device to non-blocking: %s",
+          strerror(errno));
+    ::close(fd);
+    return -1;
+  }
+
+  for (;;) {
+    struct rfkill_event event {};
+    ssize_t res = read(fd, &event, sizeof(event));
+    if (res < 0) {
+      ALOGE("error reading rfkill events: %s", strerror(errno));
+      break;
+    }
+
+    ALOGI("index:%d type:%d op:%d", event.idx, event.type, event.op);
+
+    if (event.op == RFKILL_OP_ADD && event.type == RFKILL_TYPE_BLUETOOTH) {
+      rfkill_bt_index_ = event.idx;
+      rfkill_fd_ = fd;
+      return 0;
+    }
+  }
+
+  ::close(fd);
+  return -1;
+}
+
+// Block or unblock Bluetooth.
+int NetBluetoothMgmt::rfkill(int block) {
+  if (rfkill_fd_ == -1) {
+    openRfkill();
+  }
+
+  if (rfkill_fd_ == -1) {
+    ALOGE("rfkill unavailable");
+    return -1;
+  }
+
+  struct rfkill_event event = {
+      .idx = static_cast<uint32_t>(rfkill_bt_index_),
+      .type = RFKILL_TYPE_BLUETOOTH,
+      .op = RFKILL_OP_CHANGE,
+      .soft = static_cast<uint8_t>(block),
+      .hard = 0,
+  };
+
+  int res = write(rfkill_fd_, &event, sizeof(event));
+  if (res < 0) {
+    ALOGE("error writing rfkill command: %s", strerror(errno));
+    return -1;
+  }
+
+  return 0;
+}
+
+int NetBluetoothMgmt::openHci(int hci_interface) {
+  ALOGI("opening hci interface %d", hci_interface);
+
+  // Block Bluetooth.
+  rfkill(1);
+
+  // Wait for the HCI interface to complete initialization or to come online.
+  if (waitHciDev(hci_interface)) {
+    ALOGE("hci interface %d not found", hci_interface);
+    return -1;
+  }
+
+  // Open the raw HCI socket.
+  int fd = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
+  if (fd < 0) {
+    ALOGE("unable to open raw bluetooth socket: %s", strerror(errno));
+    return -1;
+  }
+
+  struct sockaddr_hci hci_addr = {
+      .hci_family = AF_BLUETOOTH,
+      .hci_dev = static_cast<uint16_t>(hci_interface),
+      .hci_channel = HCI_CHANNEL_USER,
+  };
+
+  // Bind the socket to the selected interface.
+  if (bind(fd, (struct sockaddr*)&hci_addr, sizeof(hci_addr)) < 0) {
+    ALOGE("unable to bind bluetooth user channel: %s", strerror(errno));
+    ::close(fd);
+    return -1;
+  }
+
+  ALOGI("hci interface %d ready", hci_interface);
+  bt_fd_ = fd;
+  return fd;
+}
+
+void NetBluetoothMgmt::closeHci() {
+  if (bt_fd_ != -1) {
+    ::close(bt_fd_);
+    bt_fd_ = -1;
+  }
+
+  // Unblock Bluetooth.
+  rfkill(0);
+}
+
+}  // namespace aidl::android::hardware::bluetooth::impl