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