1 /*
2 * rfcomm_sdp.c
3 *
4 * Copyright (c) 2003 Maksim Yevmenkin <m_evmenkin@yahoo.com>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $Id: rfcomm_sdp.c,v 1.1 2003/09/07 18:15:55 max Exp $
29 * $FreeBSD$
30 */
31 #define L2CAP_SOCKET_CHECKED
32 #include <bluetooth.h>
33 #include <errno.h>
34 #include <sdp.h>
35 #include <stdio.h>
36
37 #undef PROTOCOL_DESCRIPTOR_LIST_BUFFER_SIZE
38 #define PROTOCOL_DESCRIPTOR_LIST_BUFFER_SIZE 256
39
40 #undef PROTOCOL_DESCRIPTOR_LIST_MINIMAL_SIZE
41 #define PROTOCOL_DESCRIPTOR_LIST_MINIMAL_SIZE 12
42
43 static int rfcomm_proto_list_parse (uint8_t const *start, uint8_t const *end,
44 int *channel, int *error);
45
46 /*
47 * Lookup RFCOMM channel number in the Protocol Descriptor List
48 */
49
50 #undef rfcomm_channel_lookup_exit
51 #define rfcomm_channel_lookup_exit(e) { \
52 if (error != NULL) \
53 *error = (e); \
54 if (ss != NULL) { \
55 sdp_close(ss); \
56 ss = NULL; \
57 } \
58 return (((e) == 0)? 0 : -1); \
59 }
60
61 int
rfcomm_channel_lookup(bdaddr_t const * local,bdaddr_t const * remote,int service,int * channel,int * error)62 rfcomm_channel_lookup(bdaddr_t const *local, bdaddr_t const *remote,
63 int service, int *channel, int *error)
64 {
65 uint8_t buffer[PROTOCOL_DESCRIPTOR_LIST_BUFFER_SIZE];
66 void *ss = NULL;
67 uint16_t serv = (uint16_t) service;
68 uint32_t attr = SDP_ATTR_RANGE(
69 SDP_ATTR_PROTOCOL_DESCRIPTOR_LIST,
70 SDP_ATTR_PROTOCOL_DESCRIPTOR_LIST);
71 sdp_attr_t proto = { SDP_ATTR_INVALID,0,sizeof(buffer),buffer };
72 uint32_t type, len;
73
74 if (local == NULL)
75 local = NG_HCI_BDADDR_ANY;
76 if (remote == NULL || channel == NULL)
77 rfcomm_channel_lookup_exit(EINVAL);
78
79 if ((ss = sdp_open(local, remote)) == NULL)
80 rfcomm_channel_lookup_exit(ENOMEM);
81 if (sdp_error(ss) != 0)
82 rfcomm_channel_lookup_exit(sdp_error(ss));
83
84 if (sdp_search(ss, 1, &serv, 1, &attr, 1, &proto) != 0)
85 rfcomm_channel_lookup_exit(sdp_error(ss));
86 if (proto.flags != SDP_ATTR_OK)
87 rfcomm_channel_lookup_exit(ENOATTR);
88
89 sdp_close(ss);
90 ss = NULL;
91
92 /*
93 * If it is possible for more than one kind of protocol stack to be
94 * used to gain access to the service, the ProtocolDescriptorList
95 * takes the form of a data element alternative. We always use the
96 * first protocol stack.
97 *
98 * A minimal Protocol Descriptor List for RFCOMM based service would
99 * look like
100 *
101 * seq8 len8 - 2 bytes
102 * seq8 len8 - 2 bytes
103 * uuid16 value16 - 3 bytes L2CAP
104 * seq8 len8 - 2 bytes
105 * uuid16 value16 - 3 bytes RFCOMM
106 * uint8 value8 - 2 bytes RFCOMM param #1
107 * =========
108 * 14 bytes
109 *
110 * Lets not count first [seq8 len8] wrapper, so the minimal size of
111 * the Protocol Descriptor List (the data we are actually interested
112 * in) for RFCOMM based service would be 12 bytes.
113 */
114
115 if (proto.vlen < PROTOCOL_DESCRIPTOR_LIST_MINIMAL_SIZE)
116 rfcomm_channel_lookup_exit(EINVAL);
117
118 SDP_GET8(type, proto.value);
119
120 if (type == SDP_DATA_ALT8) {
121 SDP_GET8(len, proto.value);
122 } else if (type == SDP_DATA_ALT16) {
123 SDP_GET16(len, proto.value);
124 } else if (type == SDP_DATA_ALT32) {
125 SDP_GET32(len, proto.value);
126 } else
127 len = 0;
128
129 if (len > 0)
130 SDP_GET8(type, proto.value);
131
132 switch (type) {
133 case SDP_DATA_SEQ8:
134 SDP_GET8(len, proto.value);
135 break;
136
137 case SDP_DATA_SEQ16:
138 SDP_GET16(len, proto.value);
139 break;
140
141 case SDP_DATA_SEQ32:
142 SDP_GET32(len, proto.value);
143 break;
144
145 default:
146 rfcomm_channel_lookup_exit(ENOATTR);
147 /* NOT REACHED */
148 }
149
150 if (len < PROTOCOL_DESCRIPTOR_LIST_MINIMAL_SIZE)
151 rfcomm_channel_lookup_exit(EINVAL);
152
153 return (rfcomm_proto_list_parse(proto.value,
154 buffer + proto.vlen, channel, error));
155 }
156
157 /*
158 * Parse protocol descriptor list
159 *
160 * The ProtocolDescriptorList attribute describes one or more protocol
161 * stacks that may be used to gain access to the service described by
162 * the service record. If the ProtocolDescriptorList describes a single
163 * stack, it takes the form of a data element sequence in which each
164 * element of the sequence is a protocol descriptor.
165 */
166
167 #undef rfcomm_proto_list_parse_exit
168 #define rfcomm_proto_list_parse_exit(e) { \
169 if (error != NULL) \
170 *error = (e); \
171 return (((e) == 0)? 0 : -1); \
172 }
173
174 static int
rfcomm_proto_list_parse(uint8_t const * start,uint8_t const * end,int * channel,int * error)175 rfcomm_proto_list_parse(uint8_t const *start, uint8_t const *end,
176 int *channel, int *error)
177 {
178 int type, len, value;
179
180 while (start < end) {
181
182 /*
183 * Parse protocol descriptor
184 *
185 * A protocol descriptor identifies a communications protocol
186 * and provides protocol specific parameters. A protocol
187 * descriptor is represented as a data element sequence. The
188 * first data element in the sequence must be the UUID that
189 * identifies the protocol. Additional data elements optionally
190 * provide protocol specific information, such as the L2CAP
191 * protocol/service multiplexer (PSM) and the RFCOMM server
192 * channel number (CN).
193 */
194
195 /* We must have at least one byte (type) */
196 if (end - start < 1)
197 rfcomm_proto_list_parse_exit(EINVAL)
198
199 SDP_GET8(type, start);
200 switch (type) {
201 case SDP_DATA_SEQ8:
202 SDP_GET8(len, start);
203 break;
204
205 case SDP_DATA_SEQ16:
206 SDP_GET16(len, start);
207 break;
208
209 case SDP_DATA_SEQ32:
210 SDP_GET32(len, start);
211 break;
212
213 default:
214 rfcomm_proto_list_parse_exit(ENOATTR)
215 /* NOT REACHED */
216 }
217
218 /* We must have at least 3 bytes (type + UUID16) */
219 if (end - start < 3)
220 rfcomm_proto_list_parse_exit(EINVAL);
221
222 /* Get protocol UUID */
223 SDP_GET8(type, start); len -= sizeof(uint8_t);
224 switch (type) {
225 case SDP_DATA_UUID16:
226 SDP_GET16(value, start); len -= sizeof(uint16_t);
227 if (value != SDP_UUID_PROTOCOL_RFCOMM)
228 goto next_protocol;
229 break;
230
231 case SDP_DATA_UUID32: /* XXX FIXME can we have 32-bit UUID */
232 case SDP_DATA_UUID128: /* XXX FIXME can we have 128-bit UUID */
233 default:
234 rfcomm_proto_list_parse_exit(ENOATTR);
235 /* NOT REACHED */
236 }
237
238 /*
239 * First protocol specific parameter for RFCOMM procotol must
240 * be uint8 that represents RFCOMM channel number. So we must
241 * have at least two bytes.
242 */
243
244 if (end - start < 2)
245 rfcomm_proto_list_parse_exit(EINVAL);
246
247 SDP_GET8(type, start);
248 if (type != SDP_DATA_UINT8)
249 rfcomm_proto_list_parse_exit(ENOATTR);
250
251 SDP_GET8(*channel, start);
252
253 rfcomm_proto_list_parse_exit(0);
254 /* NOT REACHED */
255 next_protocol:
256 start += len;
257 }
258
259 /*
260 * If we got here then it means we could not find RFCOMM protocol
261 * descriptor, but the reply format was actually valid.
262 */
263
264 rfcomm_proto_list_parse_exit(ENOATTR);
265 }
266
267