Diff: BTstack/l2cap_signaling.c

Revision:

0:1ed23ab1345f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/BTstack/l2cap_signaling.c	Tue Jun 26 14:27:45 2012 +0000
@@ -0,0 +1,128 @@
+/*
+ * Copyright (C) 2009-2012 by Matthias Ringwald
+ *
+ * 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.
+ * 3. Neither the name of the copyright holders nor the names of
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ * 4. Any redistribution, use, or modification is done solely for
+ *    personal benefit and not for any commercial purpose or for
+ *    monetary gain.
+ *
+ * THIS SOFTWARE IS PROVIDED BY MATTHIAS RINGWALD 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 MATTHIAS
+ * RINGWALD 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.
+ *
+ * Please inquire about commercial licensing options at btstack@ringwald.ch
+ *
+ */
+
+/*
+ *  l2cap_signaling.h
+ *
+ *  Created by Matthias Ringwald on 7/23/09.
+ */
+
+#include "l2cap_signaling.h"
+
+#include <string.h>
+
+static char *l2cap_signaling_commands_format[] = {
+"D",    // 0x01 command reject: reason {cmd not understood (0), sig MTU exceeded (2:max sig MTU), invalid CID (4:req CID)}, data len, data
+"22",   // 0x02 connection request: PSM, Source CID
+"2222", // 0x03 connection response: Dest CID, Source CID, Result, Status
+"22D",  // 0x04 config request: Dest CID, Flags, Configuration options
+"222D", // 0x05 config response: Source CID, Flags, Result, Configuration options
+"22",   // 0x06 disconection request: Dest CID, Source CID
+"22",   // 0x07 disconection response: Dest CID, Source CID
+"D",    // 0x08 echo request: Data
+"D",    // 0x09 echo response: Data
+"2",    // 0x0a information request: InfoType {1=Connectionless MTU, 2=Extended features supported}
+"22D",  // 0x0b information response: InfoType, Result, Data
+};
+
+uint8_t   sig_seq_nr  = 0xff;
+uint16_t  source_cid  = 0x40;
+
+uint8_t l2cap_next_sig_id(void){
+    if (sig_seq_nr == 0xff) {
+        sig_seq_nr = 1;
+    } else {
+        sig_seq_nr++;
+    }
+    return sig_seq_nr;
+}
+
+uint16_t l2cap_next_local_cid(void){
+    return source_cid++;
+}
+
+uint16_t l2cap_create_signaling_internal(uint8_t * acl_buffer, hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, va_list argptr){
+    
+    // 0 - Connection handle : PB=10 : BC=00 
+    bt_store_16(acl_buffer, 0, handle | (2 << 12) | (0 << 14));
+    // 6 - L2CAP channel = 1
+    bt_store_16(acl_buffer, 6, 1);
+    // 8 - Code
+    acl_buffer[8] = cmd;
+    // 9 - id (!= 0 sequentially)
+    acl_buffer[9] = identifier;
+    
+    // 12 - L2CAP signaling parameters
+    uint16_t pos = 12;
+    const char *format = l2cap_signaling_commands_format[cmd-1];
+    uint16_t word;
+    uint8_t * ptr;
+    while (*format) {
+        switch(*format) {
+            case '1': //  8 bit value
+            case '2': // 16 bit value
+                word = va_arg(argptr, int);
+                // minimal va_arg is int: 2 bytes on 8+16 bit CPUs
+                acl_buffer[pos++] = word & 0xff;
+                if (*format == '2') {
+                    acl_buffer[pos++] = word >> 8;
+                }
+                break;
+            case 'D': // variable data. passed: len, ptr
+                word = va_arg(argptr, int);
+                ptr  = va_arg(argptr, uint8_t *);
+                memcpy(&acl_buffer[pos], ptr, word);
+                pos += word;
+                break;
+            default:
+                break;
+        }
+        format++;
+    };
+    va_end(argptr);
+    
+    // Fill in various length fields: it's the number of bytes following for ACL lenght and l2cap parameter length
+    // - the l2cap payload length is counted after the following channel id (only payload) 
+    
+    // 2 - ACL length
+    bt_store_16(acl_buffer, 2,  pos - 4);
+    // 4 - L2CAP packet length
+    bt_store_16(acl_buffer, 4,  pos - 6 - 2);
+    // 10 - L2CAP signaling parameter length
+    bt_store_16(acl_buffer, 10, pos - 12);
+    
+    return pos;
+}