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