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Commit 8c9b2552 authored by Andre Eisenbach's avatar Andre Eisenbach
Browse files

Add L2CAP signaling headers and more ACL data to btsnooz 

Increase the BTSNOOZ log buffer to 256kb and adds complete L2CAP
signaling headers as well as more data per ACL data packet. This will
allow additional RFCOMM debugging.

Fixes: 28845518
Change-Id: I19e1a4a40bb1c8d332a25283fb50635d791bc275
parent 0dc388a2

system/btif/src/btif_debug_btsnoop.cc

+54 −19
Original line number Diff line number Diff line
@@ -30,7 +30,7 @@ 


// Total btsnoop memory log buffer size

#ifndef BTSNOOP_MEM_BUFFER_SIZE

static const size_t BTSNOOP_MEM_BUFFER_SIZE = (128 * 1024);

static const size_t BTSNOOP_MEM_BUFFER_SIZE = (256 * 1024);

#endif



// Block size for copying buffers (for compression/encoding etc.)
@@ -42,27 +42,14 @@ static const uint8_t MAX_LINE_LENGTH = 128; 
static ringbuffer_t *buffer = NULL;

static uint64_t last_timestamp_ms = 0;



static size_t btsnoop_calculate_packet_length(uint16_t type, const uint8_t *data, size_t length);



static void btsnoop_cb(const uint16_t type, const uint8_t *data, const size_t length) {

  btsnooz_header_t header;



  // Only log packet content for HCI commands and events (privacy).

  size_t included_length = 0;

  switch (type) {

    case BT_EVT_TO_LM_HCI_CMD:

      included_length = length;

      break;

    case BT_EVT_TO_BTU_HCI_EVT:

      included_length = length;

      break;

    case BT_EVT_TO_LM_HCI_ACL:

    case BT_EVT_TO_BTU_HCI_ACL:

      included_length = 4;

      break;

    case BT_EVT_TO_LM_HCI_SCO:

    case BT_EVT_TO_BTU_HCI_SCO:

      included_length = 2;

      break;

  }

  size_t included_length = btsnoop_calculate_packet_length(type, data, length);

  if (included_length == 0)

    return;



  // Make room in the ring buffer
@@ -85,6 +72,54 @@ static void btsnoop_cb(const uint16_t type, const uint8_t *data, const size_t le 
  ringbuffer_insert(buffer, data, included_length);

}



static size_t btsnoop_calculate_packet_length(uint16_t type, const uint8_t *data, size_t length) {

  static const size_t HCI_ACL_HEADER_SIZE = 4;

  static const size_t L2CAP_HEADER_SIZE = 4;

  static const size_t L2CAP_CID_OFFSET = (HCI_ACL_HEADER_SIZE + 2);

  static const uint16_t L2CAP_SIGNALING_CID = 0x0001;



  // Maximum amount of ACL data to log.

  // Enough for an RFCOMM frame up to the frame check;

  // not enough for a HID report or audio data.

  static const size_t MAX_HCI_ACL_LEN = 14;



  // Calculate packet length to be included



  switch (type) {

    case BT_EVT_TO_LM_HCI_CMD:

      return length;



    case BT_EVT_TO_BTU_HCI_EVT:

      return length;



    case BT_EVT_TO_LM_HCI_ACL:

    case BT_EVT_TO_BTU_HCI_ACL:

    {

      size_t len_hci_acl = HCI_ACL_HEADER_SIZE + L2CAP_HEADER_SIZE;

      // Check if we have enough data for an L2CAP header

      if (length > len_hci_acl) {

        uint16_t l2cap_cid = data[L2CAP_CID_OFFSET] | (data[L2CAP_CID_OFFSET + 1] << 8);

        if (l2cap_cid == L2CAP_SIGNALING_CID) {

          // For the signaling CID, take the full packet.

          // That way, the PSM setup is captured, allowing decoding of PSMs down the road.

          return length;

        } else {

          // Otherwise, return as much as we reasonably can

          len_hci_acl = MAX_HCI_ACL_LEN;

        }

      }

      return len_hci_acl < length ? len_hci_acl : length;

    }



    case BT_EVT_TO_LM_HCI_SCO:

    case BT_EVT_TO_BTU_HCI_SCO:

      // We're not logging SCO packets at this time since they are not currently used.

      // FALLTHROUGH

    default:

      return 0;

  }

}



static bool btsnoop_compress(ringbuffer_t *rb_dst, ringbuffer_t *rb_src) {

  assert(rb_dst != NULL);

  assert(rb_src != NULL);