xref: /btstack/src/l2cap_signaling.c (revision cd5f23a3250874824c01a2b3326a9522fea3f99f)
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, bool is_classic, 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 > 0u) && (cmd <= num_l2cap_commands)) {
85         format = l2cap_signaling_commands_format[cmd-1u];
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 = 0x00;  // First non-automatically-flushable packet of a higher layer message
93 #ifdef ENABLE_CLASSIC
94     if (is_classic){
95         pb = hci_non_flushable_packet_boundary_flag_supported() ? 0x00 : 0x02;
96     }
97 #else
98     UNUSED(is_classic);
99 #endif
100 
101     // 0 - Connection handle : PB=pb : BC=00
102     little_endian_store_16(acl_buffer, 0u, handle | (pb << 12u) | (0u << 14u));
103     // 6 - L2CAP channel = 1
104     little_endian_store_16(acl_buffer, 6, cid);
105     // 8 - Code
106     acl_buffer[8] = cmd;
107     // 9 - id (!= 0 sequentially)
108     acl_buffer[9] = identifier;
109 
110     // 12 - L2CAP signaling parameters
111     uint16_t pos = 12;
112     uint16_t word;
113     uint8_t * ptr;
114     while (*format) {
115         switch(*format) {
116             case '1': //  8 bit value
117             case '2': // 16 bit value
118                 word = va_arg(argptr, int);
119                 // minimal va_arg is int: 2 bytes on 8+16 bit CPUs
120                 acl_buffer[pos++] = word & 0xffu;
121                 if (*format == '2') {
122                     acl_buffer[pos++] = word >> 8;
123                 }
124                 break;
125             case 'D': // variable data. passed: len, ptr
126                 word = va_arg(argptr, int);
127                 ptr  = va_arg(argptr, uint8_t *);
128                 (void)memcpy(&acl_buffer[pos], ptr, word);
129                 pos += word;
130                 break;
131             default:
132                 break;
133         }
134         format++;
135     };
136     va_end(argptr);
137 
138     // Fill in various length fields: it's the number of bytes following for ACL lenght and l2cap parameter length
139     // - the l2cap payload length is counted after the following channel id (only payload)
140 
141     // 2 - ACL length
142     little_endian_store_16(acl_buffer, 2u,  pos - 4u);
143     // 4 - L2CAP packet length
144     little_endian_store_16(acl_buffer, 4u,  pos - 6u - 2u);
145     // 10 - L2CAP signaling parameter length
146     little_endian_store_16(acl_buffer, 10u, pos - 12u);
147 
148     return pos;
149 }
150 
151 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){
152     return l2cap_create_signaling_internal(acl_buffer, handle, true, 1, cmd, identifier, argptr);
153 }
154 
155 #ifdef ENABLE_BLE
156 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){
157     return l2cap_create_signaling_internal(acl_buffer, handle, false, 5, cmd, identifier, argptr);
158 }
159 #endif
160