1 /* 2 * l2cap_signaling.h 3 * 4 * Created by Matthias Ringwald on 7/23/09. 5 */ 6 7 #include "l2cap_signaling.h" 8 9 #include <string.h> 10 11 static char *l2cap_signaling_commands_format[] = { 12 "D", // 0x01 command reject: reason {cmd not understood (0), sig MTU exceeded (2:max sig MTU), invalid CID (4:req CID)}, data len, data 13 "22", // 0x02 connection request: PSM, Source CID 14 "2222", // 0x03 connection response: Dest CID, Source CID, Result, Status 15 "22D", // 0x04 config request: Dest CID, Flags, Configuration options 16 "222D", // 0x05 config response: Source CID, Flags, Result, Configuration options 17 "22", // 0x06 disconection request: Dest CID, Source CID 18 "22", // 0x07 disconection response: Dest CID, Source CID 19 "D", // 0x08 echo request: Data 20 "D", // 0x09 echo response: Data 21 "2", // 0x0a information request: InfoType {1=Connectionless MTU, 2=Extended features supported} 22 "22D", // 0x0b information response: InfoType, Result, Data 23 }; 24 25 uint8_t sig_seq_nr = 0xff; 26 uint16_t source_cid = 0x40; 27 28 uint8_t l2cap_next_sig_id(void){ 29 if (sig_seq_nr == 0xff) { 30 sig_seq_nr = 1; 31 } else { 32 sig_seq_nr++; 33 } 34 return sig_seq_nr; 35 } 36 37 uint16_t l2cap_next_source_cid(void){ 38 return source_cid++; 39 } 40 41 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){ 42 43 // 0 - Connection handle : PB=10 : BC=00 44 bt_store_16(acl_buffer, 0, handle | (2 << 12) | (0 << 14)); 45 // 6 - L2CAP channel = 1 46 bt_store_16(acl_buffer, 6, 1); 47 // 8 - Code 48 acl_buffer[8] = cmd; 49 // 9 - id (!= 0 sequentially) 50 acl_buffer[9] = identifier; 51 52 // 12 - L2CAP signaling parameters 53 uint16_t pos = 12; 54 const char *format = l2cap_signaling_commands_format[cmd-1]; 55 uint16_t word; 56 uint8_t * ptr; 57 while (*format) { 58 switch(*format) { 59 case '1': // 8 bit value 60 case '2': // 16 bit value 61 word = va_arg(argptr, int); 62 // minimal va_arg is int: 2 bytes on 8+16 bit CPUs 63 acl_buffer[pos++] = word & 0xff; 64 if (*format == '2') { 65 acl_buffer[pos++] = word >> 8; 66 } 67 break; 68 case 'D': // variable data. passed: len, ptr 69 word = va_arg(argptr, int); 70 ptr = va_arg(argptr, uint8_t *); 71 memcpy(&acl_buffer[pos], ptr, word); 72 pos += word; 73 break; 74 default: 75 break; 76 } 77 format++; 78 }; 79 va_end(argptr); 80 81 // Fill in various length fields: it's the number of bytes following for ACL lenght and l2cap parameter length 82 // - the l2cap payload length is counted after the following channel id (only payload) 83 84 // 2 - ACL length 85 bt_store_16(acl_buffer, 2, pos - 4); 86 // 4 - L2CAP packet length 87 bt_store_16(acl_buffer, 4, pos - 6 - 2); 88 // 10 - L2CAP signaling parameter length 89 bt_store_16(acl_buffer, 10, pos - 12); 90 91 return pos; 92 } 93