| # Copyright (c) 2013 The Chromium OS Authors. All rights reserved. |
| # Use of this source code is governed by a BSD-style license that can be |
| # found in the LICENSE file. |
| |
| import socket |
| import struct |
| |
| import btsocket |
| |
| SDP_HDR_FORMAT = '>BHH' |
| SDP_HDR_SIZE = struct.calcsize(SDP_HDR_FORMAT) |
| SDP_TID_CNT = 1 << 16 |
| SDP_MAX_SSR_UUIDS_CNT = 12 |
| SDP_BODY_CNT_FORMAT = '>HH' |
| SDP_BODY_CNT_SIZE = struct.calcsize(SDP_BODY_CNT_FORMAT) |
| |
| # Constants from lib/sdp.h in BlueZ source |
| SDP_RESPONSE_TIMEOUT = 20 |
| SDP_REQ_BUFFER_SIZE = 2048 |
| SDP_RSP_BUFFER_SIZE = 65535 |
| SDP_PDU_CHUNK_SIZE = 1024 |
| |
| SDP_PSM = 0x0001 |
| |
| SDP_UUID = 0x0001 |
| |
| SDP_DATA_NIL = 0x00 |
| SDP_UINT8 = 0x08 |
| SDP_UINT16 = 0x09 |
| SDP_UINT32 = 0x0A |
| SDP_UINT64 = 0x0B |
| SDP_UINT128 = 0x0C |
| SDP_INT8 = 0x10 |
| SDP_INT16 = 0x11 |
| SDP_INT32 = 0x12 |
| SDP_INT64 = 0x13 |
| SDP_INT128 = 0x14 |
| SDP_UUID_UNSPEC = 0x18 |
| SDP_UUID16 = 0x19 |
| SDP_UUID32 = 0x1A |
| SDP_UUID128 = 0x1C |
| SDP_TEXT_STR_UNSPEC = 0x20 |
| SDP_TEXT_STR8 = 0x25 |
| SDP_TEXT_STR16 = 0x26 |
| SDP_TEXT_STR32 = 0x27 |
| SDP_BOOL = 0x28 |
| SDP_SEQ_UNSPEC = 0x30 |
| SDP_SEQ8 = 0x35 |
| SDP_SEQ16 = 0x36 |
| SDP_SEQ32 = 0x37 |
| SDP_ALT_UNSPEC = 0x38 |
| SDP_ALT8 = 0x3D |
| SDP_ALT16 = 0x3E |
| SDP_ALT32 = 0x3F |
| SDP_URL_STR_UNSPEC = 0x40 |
| SDP_URL_STR8 = 0x45 |
| SDP_URL_STR16 = 0x46 |
| SDP_URL_STR32 = 0x47 |
| |
| SDP_ERROR_RSP = 0x01 |
| SDP_SVC_SEARCH_REQ = 0x02 |
| SDP_SVC_SEARCH_RSP = 0x03 |
| SDP_SVC_ATTR_REQ = 0x04 |
| SDP_SVC_ATTR_RSP = 0x05 |
| SDP_SVC_SEARCH_ATTR_REQ = 0x06 |
| SDP_SVC_SEARCH_ATTR_RSP = 0x07 |
| |
| |
| class BluetoothSDPSocketError(Exception): |
| """Error raised for SDP-related issues with BluetoothSDPSocket.""" |
| pass |
| |
| |
| class BluetoothSDPSocket(btsocket.socket): |
| """Bluetooth SDP Socket. |
| |
| BluetoothSDPSocket wraps the btsocket.socket() class to implement |
| the necessary send and receive methods for the SDP protocol. |
| |
| """ |
| |
| def __init__(self): |
| super(BluetoothSDPSocket, self).__init__(family=btsocket.AF_BLUETOOTH, |
| type=socket.SOCK_SEQPACKET, |
| proto=btsocket.BTPROTO_L2CAP) |
| self.tid = 0 |
| |
| |
| def gen_tid(self): |
| """Generate new Transaction ID |
| |
| @return Transaction ID |
| |
| """ |
| self.tid = (self.tid + 1) % SDP_TID_CNT |
| return self.tid |
| |
| |
| def connect(self, address): |
| """Connect to device with the given address |
| |
| @param address: Bluetooth address. |
| |
| """ |
| super(BluetoothSDPSocket, self).connect((address, SDP_PSM)) |
| |
| |
| def send_request(self, code, tid, data): |
| """Send a request to the socket. |
| |
| @param code: Request code. |
| @param tid: Transaction ID. |
| @param data: Parameters as bytearray or str. |
| |
| @raise BluetoothSDPSocketError: if 'send' to the socket didn't succeed. |
| |
| """ |
| msg = struct.pack(SDP_HDR_FORMAT, code, tid, len(data)) + data |
| |
| length = self.send(msg) |
| if length != len(msg): |
| raise BluetoothSDPSocketError('Short write on socket') |
| |
| |
| def recv_response(self): |
| """Receive a single response from the socket. |
| |
| The response data is not parsed. |
| |
| Use settimeout() to set whether this method will block if there is no |
| reply, return immediately or wait for a specific length of time before |
| timing out and raising TimeoutError. |
| |
| @return tuple of (code, tid, data) |
| @raise BluetoothSDPSocketError: if the received packet is too small or |
| if size of the packet differs from size written in header |
| |
| """ |
| # Read the response from the socket |
| response = self.recv(SDP_RSP_BUFFER_SIZE) |
| |
| if len(response) < SDP_HDR_SIZE: |
| raise BluetoothSDPSocketError('Short read on socket') |
| |
| code, tid, length = struct.unpack_from(SDP_HDR_FORMAT, response) |
| data = response[SDP_HDR_SIZE:] |
| |
| if length != len(data): |
| raise BluetoothSDPSocketError('Short read on socket') |
| |
| return code, tid, data |
| |
| |
| def send_request_and_wait(self, req_code, req_data): |
| """Send a request to the socket and wait for the response. |
| |
| The response data is not parsed. |
| |
| @param req_code: Request code. |
| @param req_data: Parameters as bytearray or str. |
| |
| Use settimeout() to set whether this method will block if there is no |
| reply, return immediately or wait for a specific length of time before |
| timing out and raising TimeoutError. |
| |
| @return tuple of (rsp_code, data) |
| @raise BluetoothSDPSocketError: if Transaction ID of the response |
| doesn't match to Transaction ID sent in request |
| |
| """ |
| req_tid = self.gen_tid() |
| self.send_request(req_code, req_tid, req_data) |
| rsp_code, rsp_tid, rsp_data = self.recv_response() |
| |
| if req_tid != rsp_tid: |
| raise BluetoothSDPSocketError("Transaction IDs for request and " |
| "response don't match") |
| |
| return rsp_code, rsp_data |
| |
| |
| def _pack_uuids(self, uuids): |
| """Pack a list of UUIDs to a binary sequence |
| |
| @param uuids: List of UUIDs in 32-bit format. |
| |
| @return packed list as a str |
| @raise BluetoothSDPSocketError: if list of UUIDs after packing is larger |
| than or equal to 2^32 bytes |
| |
| """ |
| res = '' |
| for uuid in uuids: |
| res += struct.pack('>BI', SDP_UUID32, uuid) |
| |
| size = len(res) |
| if size < (1 << 8): |
| header = struct.pack('>BB', SDP_SEQ8, size) |
| elif size < (1 << 16): |
| header = struct.pack('>BH', SDP_SEQ16, size) |
| elif size < (1 << 32): |
| header = struct.pack('>BI', SDP_SEQ32, size) |
| else: |
| raise BluetoothSDPSocketError('List is too long') |
| |
| res = header + res |
| |
| return res |
| |
| |
| def _unpack_uuids(self, response): |
| """Unpack SDP response |
| |
| @param response: body of raw SDP response. |
| |
| @return tople of (uuids, cont_state) |
| |
| """ |
| total_cnt, cur_cnt = struct.unpack_from(SDP_BODY_CNT_FORMAT, response) |
| scanned = SDP_BODY_CNT_SIZE |
| uuids = [] |
| for i in range(cur_cnt): |
| uuid, = struct.unpack_from('>I', response, scanned) |
| uuids.append(uuid) |
| scanned += 4 |
| |
| cont_state = response[scanned:] |
| return uuids, cont_state |
| |
| |
| def service_search_request(self, uuids, max_rec_cnt): |
| """Send a Service Search Request |
| |
| @param uuids: List of UUIDs (in 32-bit format) to look for. |
| @param max_rec_cnt: Maximum count of returned service records. |
| |
| @return list of found services' service record handles |
| @raise BluetoothSDPSocketError: arguments do not match the SDP |
| restrictions or if the response has an incorrect code |
| |
| """ |
| if max_rec_cnt < 1 or max_rec_cnt > 0xFFFF: |
| raise BluetoothSDPSocketError('MaximumServiceRecordCount must be ' |
| 'between 1 and 0xFFFF, inclusive') |
| |
| if len(uuids) > SDP_MAX_SSR_UUIDS_CNT: |
| raise BluetoothSDPSocketError('Too many UUIDs') |
| |
| pattern = self._pack_uuids(uuids) + struct.pack('>H', max_rec_cnt) |
| cont_state = '\0' |
| handles = [] |
| |
| while True: |
| request = pattern + cont_state |
| code, response = self.send_request_and_wait( |
| SDP_SVC_SEARCH_REQ, request) |
| |
| if code != SDP_SVC_SEARCH_RSP: |
| raise BluetoothSDPSocketError('Incorrect response code') |
| |
| cur_list, cont_state = self._unpack_uuids(response) |
| handles.extend(cur_list) |
| if cont_state == '\0': |
| break |
| |
| return handles |
