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 void null_event_handler(uint8_t *packet, uint16_t size); 17 static void null_data_handler(uint16_t source_cid, uint8_t *packet, uint16_t size); 18 19 static uint8_t * sig_buffer = NULL; 20 static linked_list_t l2cap_channels = NULL; 21 static uint8_t * acl_buffer = NULL; 22 static void (*event_packet_handler) (uint8_t *packet, uint16_t size) = null_event_handler; 23 static void (*data_packet_handler) (uint16_t source_cid, uint8_t *packet, uint16_t size) = null_data_handler; 24 static connection_t * capture_connection = NULL; 25 26 void l2cap_init(){ 27 sig_buffer = malloc( 48 ); 28 acl_buffer = malloc( 255 + 8 ); 29 30 // 31 // register callbacks with HCI 32 // 33 hci_register_event_packet_handler(&l2cap_event_handler); 34 hci_register_acl_packet_handler(&l2cap_acl_handler); 35 } 36 37 38 /** Register L2CAP packet handlers */ 39 static void null_event_handler(uint8_t *packet, uint16_t size){ 40 } 41 static void null_data_handler(uint16_t source_cid, uint8_t *packet, uint16_t size){ 42 } 43 void l2cap_register_event_packet_handler(void (*handler)(uint8_t *packet, uint16_t size)){ 44 event_packet_handler = handler; 45 } 46 void l2cap_register_data_packet_handler (void (*handler)(uint16_t source_cid, uint8_t *packet, uint16_t size)){ 47 data_packet_handler = handler; 48 } 49 50 int l2cap_send_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, ...){ 51 va_list argptr; 52 va_start(argptr, identifier); 53 uint16_t len = l2cap_create_signaling_internal(sig_buffer, handle, cmd, identifier, argptr); 54 va_end(argptr); 55 return hci_send_acl_packet(sig_buffer, len); 56 } 57 58 l2cap_channel_t * l2cap_get_channel_for_source_cid(uint16_t source_cid){ 59 linked_item_t *it; 60 l2cap_channel_t * channel; 61 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 62 channel = (l2cap_channel_t *) it; 63 if ( channel->source_cid == source_cid) { 64 return channel; 65 } 66 } 67 return NULL; 68 } 69 70 // open outgoing L2CAP channel 71 void l2cap_create_channel_internal(connection_t * connection, bd_addr_t address, uint16_t psm){ 72 73 // alloc structure 74 l2cap_channel_t * chan = malloc(sizeof(l2cap_channel_t)); 75 // TODO: emit error event 76 if (!chan) return; 77 78 // fill in 79 BD_ADDR_COPY(chan->address, address); 80 chan->psm = psm; 81 chan->handle = 0; 82 chan->connection = connection; 83 84 // set initial state 85 chan->state = L2CAP_STATE_CLOSED; 86 chan->sig_id = L2CAP_SIG_ID_INVALID; 87 88 // add to connections list 89 linked_list_add(&l2cap_channels, (linked_item_t *) chan); 90 91 // send connection request 92 // BD_ADDR, Packet_Type, Page_Scan_Repetition_Mode, Reserved, Clock_Offset, Allow_Role_Switch 93 hci_send_cmd(&hci_create_connection, address, 0x18, 0, 0, 0, 0); 94 } 95 96 void l2cap_disconnect_internal(uint16_t source_cid, uint8_t reason){ 97 // find channel for source_cid 98 l2cap_channel_t * channel = l2cap_get_channel_for_source_cid(source_cid); 99 if (channel) { 100 channel->sig_id = l2cap_next_sig_id(); 101 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_REQUEST, channel->sig_id, channel->dest_cid, channel->source_cid); 102 channel->state = L2CAP_STATE_WAIT_DISCONNECT; 103 } 104 } 105 106 107 void l2cap_event_handler( uint8_t *packet, uint16_t size ){ 108 // handle connection complete events 109 if (packet[0] == HCI_EVENT_CONNECTION_COMPLETE && packet[2] == 0){ 110 bd_addr_t address; 111 bt_flip_addr(address, &packet[5]); 112 113 linked_item_t *it; 114 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 115 l2cap_channel_t * chan = (l2cap_channel_t *) it; 116 if ( ! BD_ADDR_CMP( chan->address, address) ){ 117 if (chan->state == L2CAP_STATE_CLOSED) { 118 chan->handle = READ_BT_16(packet, 3); 119 chan->sig_id = l2cap_next_sig_id(); 120 chan->source_cid = l2cap_next_source_cid(); 121 122 l2cap_send_signaling_packet( chan->handle, CONNECTION_REQUEST, chan->sig_id, chan->psm, chan->source_cid); 123 124 chan->state = L2CAP_STATE_WAIT_CONNECT_RSP; 125 } 126 } 127 } 128 } 129 130 // handle disconnection complete events 131 if (packet[0] == HCI_EVENT_DISCONNECTION_COMPLETE) { 132 // send l2cap disconnect events for all channels on this handle 133 hci_con_handle_t handle = READ_BT_16(packet, 3); 134 linked_item_t *it; 135 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 136 l2cap_channel_t * channel = (l2cap_channel_t *) it; 137 if ( channel->handle == handle ){ 138 l2cap_finialize_channel_close(channel); 139 } 140 } 141 } 142 143 // HCI Connection Timeouts 144 if (packet[0] == HCI_EVENT_L2CAP_TIMEOUT_CHECK){ 145 hci_con_handle_t handle = READ_BT_16(packet, 2); 146 linked_item_t *it; 147 l2cap_channel_t * channel; 148 int used = 0; 149 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 150 channel = (l2cap_channel_t *) it; 151 if (channel->handle == handle) { 152 used = 1; 153 } 154 } 155 if (!used) { 156 hci_send_cmd(&hci_disconnect, handle, 0x13); // remote closed connection 157 } 158 } 159 160 (*event_packet_handler)(packet, size); 161 } 162 163 void l2cap_signaling_handler(l2cap_channel_t *channel, uint8_t *packet, uint16_t size){ 164 165 static uint8_t config_options[] = { 1, 2, 150, 0}; // mtu = 48 166 167 uint8_t code = READ_L2CAP_SIGNALING_CODE( packet ); 168 uint8_t identifier = READ_L2CAP_SIGNALING_IDENTIFIER( packet ); 169 170 switch (channel->state) { 171 172 case L2CAP_STATE_WAIT_CONNECT_RSP: 173 switch (code){ 174 case CONNECTION_RESPONSE: 175 if ( READ_BT_16 (packet, L2CAP_SIGNALING_DATA_OFFSET+3) == 0){ 176 // successfull connection 177 channel->dest_cid = READ_BT_16(packet, L2CAP_SIGNALING_DATA_OFFSET + 0); 178 channel->sig_id = l2cap_next_sig_id(); 179 l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->sig_id, channel->dest_cid, 0, 4, &config_options); 180 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP; 181 } else { 182 //@TODO: implement failed 183 } 184 break; 185 //@TODO: implement other signaling packets 186 } 187 break; 188 189 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP: 190 switch (code) { 191 case CONFIGURE_RESPONSE: 192 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ; 193 break; 194 } 195 break; 196 197 case L2CAP_STATE_WAIT_CONFIG_REQ: 198 switch (code) { 199 case CONFIGURE_REQUEST: 200 201 // accept the other's configuration options 202 l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, identifier, channel->dest_cid, 0, 0, size - 16, &packet[16]); 203 204 channel->state = L2CAP_STATE_OPEN; 205 l2cap_emit_channel_opened(channel); 206 break; 207 } 208 break; 209 210 case L2CAP_STATE_WAIT_DISCONNECT: 211 switch (code) { 212 case DISCONNECTION_RESPONSE: 213 l2cap_finialize_channel_close(channel); 214 break; 215 } 216 break; 217 } 218 } 219 220 // finalize closed channel 221 void l2cap_finialize_channel_close(l2cap_channel_t *channel){ 222 channel->state = L2CAP_STATE_CLOSED; 223 l2cap_emit_channel_closed(channel); 224 225 // discard channel 226 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 227 free (channel); 228 } 229 230 // 231 void l2cap_close_channels_for_connection(connection_t *connection){ 232 linked_item_t *it; 233 l2cap_channel_t * channel; 234 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 235 channel = (l2cap_channel_t *) it; 236 if ( channel->connection == connection) { 237 channel->sig_id = l2cap_next_sig_id(); 238 l2cap_send_signaling_packet( channel->handle, DISCONNECTION_REQUEST, channel->sig_id, channel->dest_cid, channel->source_cid); 239 channel->state = L2CAP_STATE_WAIT_DISCONNECT; 240 } 241 } 242 } 243 244 // notify client 245 void l2cap_emit_channel_opened(l2cap_channel_t *channel) { 246 uint8_t event[16]; 247 event[0] = HCI_EVENT_L2CAP_CHANNEL_OPENED; 248 event[1] = sizeof(event) - 2; 249 bt_flip_addr(&event[2], channel->address); 250 bt_store_16(event, 8, channel->handle); 251 bt_store_16(event, 10, channel->psm); 252 bt_store_16(event, 12, channel->source_cid); 253 bt_store_16(event, 14, channel->dest_cid); 254 socket_connection_send_packet(channel->connection, HCI_EVENT_PACKET, 0, event, sizeof(event)); 255 } 256 257 void l2cap_emit_channel_closed(l2cap_channel_t *channel) { 258 uint8_t event[4]; 259 event[0] = HCI_EVENT_L2CAP_CHANNEL_CLOSED; 260 event[1] = sizeof(event) - 2; 261 bt_store_16(event, 2, channel->source_cid); 262 socket_connection_send_packet(channel->connection, HCI_EVENT_PACKET, 0, event, sizeof(event)); 263 } 264 265 void l2cap_acl_handler( uint8_t *packet, uint16_t size ){ 266 267 // Capturing? 268 if (capture_connection) { 269 socket_connection_send_packet(capture_connection, HCI_ACL_DATA_PACKET, 0, packet, size); 270 } 271 272 // forward to higher layers - not needed yet 273 // (*data_packet_handler)(channel_id, packet, size); 274 275 // Get Channel ID and command code 276 uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet); 277 uint8_t code = READ_L2CAP_SIGNALING_CODE( packet ); 278 279 // Get Connection 280 hci_con_handle_t handle = READ_ACL_CONNECTION_HANDLE(packet); 281 282 // Signaling Packet? 283 if (channel_id == 1) { 284 285 if (code < 1 || code == 2 || code >= 8){ 286 // not for a particular channel 287 return; 288 } 289 290 // Get Signaling Identifier and potential destination CID 291 uint8_t sig_id = READ_L2CAP_SIGNALING_IDENTIFIER(packet); 292 uint16_t dest_cid = READ_BT_16(packet, L2CAP_SIGNALING_DATA_OFFSET); 293 294 // Find channel for this sig_id and connection handle 295 linked_item_t *it; 296 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 297 l2cap_channel_t * chan = (l2cap_channel_t *) it; 298 if (chan->handle == handle) { 299 if (code & 1) { 300 // match odd commands by previous signaling identifier 301 if (chan->sig_id == sig_id) { 302 l2cap_signaling_handler( chan, packet, size); 303 } 304 } else { 305 // match even commands by source channel id 306 if (chan->source_cid == dest_cid) { 307 l2cap_signaling_handler( chan, packet, size); 308 } 309 } 310 } 311 } 312 return; 313 } 314 315 // Find channel for this channel_id and connection handle 316 l2cap_channel_t * channel = l2cap_get_channel_for_source_cid(channel_id); 317 if (channel) { 318 socket_connection_send_packet(channel->connection, L2CAP_DATA_PACKET, 0, packet, size); 319 } 320 } 321 322 323 void l2cap_send_internal(uint16_t source_cid, uint8_t *data, uint16_t len){ 324 // find channel for source_cid, construct l2cap packet and send 325 l2cap_channel_t * channel = l2cap_get_channel_for_source_cid(source_cid); 326 if (channel) { 327 // 0 - Connection handle : PB=10 : BC=00 328 bt_store_16(acl_buffer, 0, channel->handle | (2 << 12) | (0 << 14)); 329 // 2 - ACL length 330 bt_store_16(acl_buffer, 2, len + 4); 331 // 4 - L2CAP packet length 332 bt_store_16(acl_buffer, 4, len + 0); 333 // 6 - L2CAP channel DEST 334 bt_store_16(acl_buffer, 6, channel->dest_cid); 335 // 8 - data 336 memcpy(&acl_buffer[8], data, len); 337 // send 338 hci_send_acl_packet(acl_buffer, len+8); 339 } 340 } 341 342 void l2cap_set_capture_connection(connection_t * connection){ 343 capture_connection = connection; 344 } 345 346