1 /* 2 * l2cap.c 3 * 4 * Logical Link Control and Adaption Protocl (L2CAP) 5 * 6 * Created by Matthias Ringwald on 5/16/09. 7 */ 8 9 #include "l2cap.h" 10 11 #include <stdarg.h> 12 #include <string.h> 13 14 #include <stdio.h> 15 16 static char *l2cap_signaling_commands_format[] = { 17 "D", // 0x01 command reject: reason {cmd not understood (0), sig MTU exceeded (2:max sig MTU), invalid CID (4:req CID)}, data len, data 18 "22", // 0x02 connection request: PSM, Source CID 19 "2222", // 0x03 connection response: Dest CID, Source CID, Result, Status 20 "22D", // 0x04 config request: Dest CID, Flags, Configuration options 21 "222D", // 0x05 config response: Source CID, Flags, Result, Configuration options 22 "22", // 0x06 disconection request: Dest CID, Source CID 23 "22", // 0x07 disconection response: Dest CID, Source CID 24 "D", // 0x08 echo request: Data 25 "D", // 0x09 echo response: Data 26 "2", // 0x0a information request: InfoType {1=Connectionless MTU, 2=Extended features supported} 27 "22D", // 0x0b information response: InfoType, Result, Data 28 }; 29 30 static uint8_t * sig_buffer; 31 32 uint8_t sig_seq_nr; 33 uint16_t local_cid; 34 35 int l2cap_send_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, ...){ 36 37 // 0 - Connection handle : PB=10 : BC=00 38 bt_store_16(sig_buffer, 0, handle | (2 << 12) | (0 << 14)); 39 // 6 - L2CAP channel = 1 40 bt_store_16(sig_buffer, 6, 1); 41 // 8 - Code 42 sig_buffer[8] = cmd; 43 // 9 - id (!= 0 sequentially) 44 sig_buffer[9] = identifier; 45 46 // 12 - L2CAP signaling parameters 47 uint16_t pos = 12; 48 va_list argptr; 49 va_start(argptr, identifier); 50 const char *format = l2cap_signaling_commands_format[cmd-1]; 51 uint16_t word; 52 uint8_t * ptr; 53 while (*format) { 54 switch(*format) { 55 case '1': // 8 bit value 56 case '2': // 16 bit value 57 word = va_arg(argptr, int); 58 // minimal va_arg is int: 2 bytes on 8+16 bit CPUs 59 sig_buffer[pos++] = word & 0xff; 60 if (*format == '2') { 61 sig_buffer[pos++] = word >> 8; 62 } 63 break; 64 case 'D': // variable data. passed: len, ptr 65 word = va_arg(argptr, int); 66 ptr = va_arg(argptr, uint8_t *); 67 memcpy(&sig_buffer[pos], ptr, word); 68 pos += word; 69 break; 70 default: 71 break; 72 } 73 format++; 74 }; 75 va_end(argptr); 76 77 // Fill in various length fields: it's the number of bytes following for ACL lenght and l2cap parameter length 78 // - the l2cap payload length is counted after the following channel id (only payload) 79 80 // 2 - ACL length 81 bt_store_16(sig_buffer, 2, pos - 4); 82 // 4 - L2CAP packet length 83 bt_store_16(sig_buffer, 4, pos - 6 - 2); 84 // 10 - L2CAP signaling parameter length 85 bt_store_16(sig_buffer, 10, pos - 12); 86 87 return hci_send_acl_packet(sig_buffer, pos); 88 } 89 90 void l2cap_init(){ 91 sig_buffer = malloc( 48 ); 92 sig_seq_nr = 1; 93 local_cid = 0x40; 94 }