xref: /btstack/src/l2cap_signaling.c (revision 8334d3d848d4b982e94c50bb19c1186089449d05)
1 /*
2  * Copyright (C) 2014 BlueKitchen GmbH
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  *
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the copyright holders nor the names of
14  *    contributors may be used to endorse or promote products derived
15  *    from this software without specific prior written permission.
16  * 4. Any redistribution, use, or modification is done solely for
17  *    personal benefit and not for any commercial purpose or for
18  *    monetary gain.
19  *
20  * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS
24  * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
26  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
27  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
30  * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  * Please inquire about commercial licensing options at
34  * [email protected]
35  *
36  */
37 
38 #define BTSTACK_FILE__ "l2cap_signaling.c"
39 
40 /*
41  *  l2cap_signaling.h
42  *
43  *  Created by Matthias Ringwald on 7/23/09.
44  */
45 
46 #include "l2cap_signaling.h"
47 #include "btstack_config.h"
48 #include "btstack_debug.h"
49 #include "hci.h"
50 
51 #include <string.h>
52 
53 static uint16_t l2cap_create_signaling_internal(uint8_t * acl_buffer, hci_con_handle_t handle, uint16_t cid, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, va_list argptr){
54 
55     static const char *l2cap_signaling_commands_format[] = {
56             "2D",    // 0x01 command reject: reason {cmd not understood (0), sig MTU exceeded (2:max sig MTU), invalid CID (4:req CID)}, data len, data
57             "22",    // 0x02 connection request: PSM, Source CID
58             "2222",  // 0x03 connection response: Dest CID, Source CID, Result, Status
59             "22D",   // 0x04 config request: Dest CID, Flags, Configuration options
60             "222D",  // 0x05 config response: Source CID, Flags, Result, Configuration options
61             "22",    // 0x06 disconection request: Dest CID, Source CID
62             "22",    // 0x07 disconection response: Dest CID, Source CID
63             "D",     // 0x08 echo request: Data
64             "D",     // 0x09 echo response: Data
65             "2",     // 0x0a information request: InfoType {1=Connectionless MTU, 2=Extended features supported}
66             "22D",   // 0x0b information response: InfoType, Result, Data
67 #ifdef ENABLE_BLE
68             NULL,    // 0x0c non-supported AMP command
69             NULL,    // 0x0d non-supported AMP command
70             NULL,    // 0x0e non-supported AMP command
71             NULL,    // 0x0f non-supported AMP command
72             NULL,    // 0x10 non-supported AMP command
73             NULL,    // 0x11 non-supported AMP command
74             "2222",  // 0x12 connection parameter update request: interval min, interval max, slave latency, timeout multipler
75             "2",     // 0x13 connection parameter update response: result
76             "22222", // 0X14 le credit based connection request: le psm, source cid, mtu, mps, initial credits
77             "22222", // 0x15 le credit based connection respone: dest cid, mtu, mps, initial credits, result
78             "22",    // 0x16 le flow control credit: source cid, credits
79 #endif
80     };
81     static const unsigned int num_l2cap_commands = sizeof(l2cap_signaling_commands_format) / sizeof(const char *);
82 
83     const char *format = NULL;
84     if ((cmd > 0) && (cmd <= num_l2cap_commands)) {
85         format = l2cap_signaling_commands_format[cmd-1];
86     }
87     if (!format){
88         log_error("l2cap_create_signaling_internal: invalid command id 0x%02x", cmd);
89         return 0;
90     }
91 
92     int pb = hci_non_flushable_packet_boundary_flag_supported() ? 0x00 : 0x02;
93 
94     // 0 - Connection handle : PB=pb : BC=00
95     little_endian_store_16(acl_buffer, 0, handle | (pb << 12) | (0 << 14));
96     // 6 - L2CAP channel = 1
97     little_endian_store_16(acl_buffer, 6, cid);
98     // 8 - Code
99     acl_buffer[8] = cmd;
100     // 9 - id (!= 0 sequentially)
101     acl_buffer[9] = identifier;
102 
103     // 12 - L2CAP signaling parameters
104     uint16_t pos = 12;
105     uint16_t word;
106     uint8_t * ptr;
107     while (*format) {
108         switch(*format) {
109             case '1': //  8 bit value
110             case '2': // 16 bit value
111                 word = va_arg(argptr, int);
112                 // minimal va_arg is int: 2 bytes on 8+16 bit CPUs
113                 acl_buffer[pos++] = word & 0xff;
114                 if (*format == '2') {
115                     acl_buffer[pos++] = word >> 8;
116                 }
117                 break;
118             case 'D': // variable data. passed: len, ptr
119                 word = va_arg(argptr, int);
120                 ptr  = va_arg(argptr, uint8_t *);
121                 (void)memcpy(&acl_buffer[pos], ptr, word);
122                 pos += word;
123                 break;
124             default:
125                 break;
126         }
127         format++;
128     };
129     va_end(argptr);
130 
131     // Fill in various length fields: it's the number of bytes following for ACL lenght and l2cap parameter length
132     // - the l2cap payload length is counted after the following channel id (only payload)
133 
134     // 2 - ACL length
135     little_endian_store_16(acl_buffer, 2,  pos - 4);
136     // 4 - L2CAP packet length
137     little_endian_store_16(acl_buffer, 4,  pos - 6 - 2);
138     // 10 - L2CAP signaling parameter length
139     little_endian_store_16(acl_buffer, 10, pos - 12);
140 
141     return pos;
142 }
143 
144 uint16_t l2cap_create_signaling_classic(uint8_t * acl_buffer, hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, va_list argptr){
145     return l2cap_create_signaling_internal(acl_buffer, handle, 1, cmd, identifier, argptr);
146 }
147 
148 #ifdef ENABLE_BLE
149 uint16_t l2cap_create_signaling_le(uint8_t * acl_buffer, hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, va_list argptr){
150     return l2cap_create_signaling_internal(acl_buffer, handle, 5, cmd, identifier, argptr);
151 }
152 #endif
153