267 lines
7.3 KiB
C
267 lines
7.3 KiB
C
/*
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* rfcomm_sdp.c
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*
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* Copyright (c) 2003 Maksim Yevmenkin <m_evmenkin@yahoo.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: rfcomm_sdp.c,v 1.1 2003/09/07 18:15:55 max Exp $
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* $FreeBSD$
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*/
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#define L2CAP_SOCKET_CHECKED
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#include <bluetooth.h>
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#include <errno.h>
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#include <sdp.h>
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#include <stdio.h>
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#undef PROTOCOL_DESCRIPTOR_LIST_BUFFER_SIZE
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#define PROTOCOL_DESCRIPTOR_LIST_BUFFER_SIZE 256
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#undef PROTOCOL_DESCRIPTOR_LIST_MINIMAL_SIZE
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#define PROTOCOL_DESCRIPTOR_LIST_MINIMAL_SIZE 12
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static int rfcomm_proto_list_parse (uint8_t const *start, uint8_t const *end,
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int *channel, int *error);
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/*
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* Lookup RFCOMM channel number in the Protocol Descriptor List
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*/
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#undef rfcomm_channel_lookup_exit
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#define rfcomm_channel_lookup_exit(e) { \
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if (error != NULL) \
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*error = (e); \
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if (ss != NULL) { \
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sdp_close(ss); \
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ss = NULL; \
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} \
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return (((e) == 0)? 0 : -1); \
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}
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int
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rfcomm_channel_lookup(bdaddr_t const *local, bdaddr_t const *remote,
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int service, int *channel, int *error)
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{
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uint8_t buffer[PROTOCOL_DESCRIPTOR_LIST_BUFFER_SIZE];
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void *ss = NULL;
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uint16_t serv = (uint16_t) service;
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uint32_t attr = SDP_ATTR_RANGE(
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SDP_ATTR_PROTOCOL_DESCRIPTOR_LIST,
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SDP_ATTR_PROTOCOL_DESCRIPTOR_LIST);
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sdp_attr_t proto = { SDP_ATTR_INVALID,0,sizeof(buffer),buffer };
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uint32_t type, len;
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if (local == NULL)
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local = NG_HCI_BDADDR_ANY;
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if (remote == NULL || channel == NULL)
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rfcomm_channel_lookup_exit(EINVAL);
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if ((ss = sdp_open(local, remote)) == NULL)
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rfcomm_channel_lookup_exit(ENOMEM);
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if (sdp_error(ss) != 0)
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rfcomm_channel_lookup_exit(sdp_error(ss));
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if (sdp_search(ss, 1, &serv, 1, &attr, 1, &proto) != 0)
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rfcomm_channel_lookup_exit(sdp_error(ss));
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if (proto.flags != SDP_ATTR_OK)
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rfcomm_channel_lookup_exit(ENOATTR);
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sdp_close(ss);
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ss = NULL;
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/*
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* If it is possible for more than one kind of protocol stack to be
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* used to gain access to the service, the ProtocolDescriptorList
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* takes the form of a data element alternative. We always use the
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* first protocol stack.
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*
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* A minimal Protocol Descriptor List for RFCOMM based service would
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* look like
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*
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* seq8 len8 - 2 bytes
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* seq8 len8 - 2 bytes
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* uuid16 value16 - 3 bytes L2CAP
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* seq8 len8 - 2 bytes
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* uuid16 value16 - 3 bytes RFCOMM
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* uint8 value8 - 2 bytes RFCOMM param #1
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* =========
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* 14 bytes
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*
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* Lets not count first [seq8 len8] wrapper, so the minimal size of
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* the Protocol Descriptor List (the data we are actually interested
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* in) for RFCOMM based service would be 12 bytes.
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*/
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if (proto.vlen < PROTOCOL_DESCRIPTOR_LIST_MINIMAL_SIZE)
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rfcomm_channel_lookup_exit(EINVAL);
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SDP_GET8(type, proto.value);
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if (type == SDP_DATA_ALT8) {
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SDP_GET8(len, proto.value);
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} else if (type == SDP_DATA_ALT16) {
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SDP_GET16(len, proto.value);
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} else if (type == SDP_DATA_ALT32) {
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SDP_GET32(len, proto.value);
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} else
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len = 0;
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if (len > 0)
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SDP_GET8(type, proto.value);
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switch (type) {
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case SDP_DATA_SEQ8:
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SDP_GET8(len, proto.value);
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break;
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case SDP_DATA_SEQ16:
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SDP_GET16(len, proto.value);
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break;
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case SDP_DATA_SEQ32:
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SDP_GET32(len, proto.value);
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break;
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default:
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rfcomm_channel_lookup_exit(ENOATTR);
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/* NOT REACHED */
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}
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if (len < PROTOCOL_DESCRIPTOR_LIST_MINIMAL_SIZE)
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rfcomm_channel_lookup_exit(EINVAL);
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return (rfcomm_proto_list_parse(proto.value,
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buffer + proto.vlen, channel, error));
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}
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/*
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* Parse protocol descriptor list
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*
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* The ProtocolDescriptorList attribute describes one or more protocol
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* stacks that may be used to gain access to the service described by
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* the service record. If the ProtocolDescriptorList describes a single
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* stack, it takes the form of a data element sequence in which each
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* element of the sequence is a protocol descriptor.
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*/
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#undef rfcomm_proto_list_parse_exit
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#define rfcomm_proto_list_parse_exit(e) { \
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if (error != NULL) \
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*error = (e); \
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return (((e) == 0)? 0 : -1); \
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}
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static int
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rfcomm_proto_list_parse(uint8_t const *start, uint8_t const *end,
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int *channel, int *error)
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{
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int type, len, value;
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while (start < end) {
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/*
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* Parse protocol descriptor
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*
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* A protocol descriptor identifies a communications protocol
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* and provides protocol specific parameters. A protocol
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* descriptor is represented as a data element sequence. The
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* first data element in the sequence must be the UUID that
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* identifies the protocol. Additional data elements optionally
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* provide protocol specific information, such as the L2CAP
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* protocol/service multiplexer (PSM) and the RFCOMM server
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* channel number (CN).
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*/
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/* We must have at least one byte (type) */
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if (end - start < 1)
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rfcomm_proto_list_parse_exit(EINVAL)
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SDP_GET8(type, start);
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switch (type) {
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case SDP_DATA_SEQ8:
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SDP_GET8(len, start);
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break;
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case SDP_DATA_SEQ16:
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SDP_GET16(len, start);
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break;
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case SDP_DATA_SEQ32:
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SDP_GET32(len, start);
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break;
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default:
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rfcomm_proto_list_parse_exit(ENOATTR)
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/* NOT REACHED */
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}
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/* We must have at least 3 bytes (type + UUID16) */
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if (end - start < 3)
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rfcomm_proto_list_parse_exit(EINVAL);
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/* Get protocol UUID */
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SDP_GET8(type, start); len -= sizeof(uint8_t);
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switch (type) {
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case SDP_DATA_UUID16:
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SDP_GET16(value, start); len -= sizeof(uint16_t);
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if (value != SDP_UUID_PROTOCOL_RFCOMM)
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goto next_protocol;
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break;
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case SDP_DATA_UUID32: /* XXX FIXME can we have 32-bit UUID */
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case SDP_DATA_UUID128: /* XXX FIXME can we have 128-bit UUID */
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default:
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rfcomm_proto_list_parse_exit(ENOATTR);
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/* NOT REACHED */
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}
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/*
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* First protocol specific parameter for RFCOMM procotol must
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* be uint8 that represents RFCOMM channel number. So we must
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* have at least two bytes.
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*/
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if (end - start < 2)
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rfcomm_proto_list_parse_exit(EINVAL);
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SDP_GET8(type, start);
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if (type != SDP_DATA_UINT8)
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rfcomm_proto_list_parse_exit(ENOATTR);
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SDP_GET8(*channel, start);
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rfcomm_proto_list_parse_exit(0);
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/* NOT REACHED */
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next_protocol:
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start += len;
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}
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/*
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* If we got here then it means we could not find RFCOMM protocol
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* descriptor, but the reply format was actually valid.
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*/
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rfcomm_proto_list_parse_exit(ENOATTR);
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}
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