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 // handle disconnection complete events 129 //@TODO:... 130 131 // forward to higher layers 132 (*event_packet_handler)(packet, size); 133 134 // forward event to clients 135 socket_connection_send_packet_all(HCI_EVENT_PACKET, 0, packet, size); 136 } 137 138 void l2cap_signaling_handler(l2cap_channel_t *channel, uint8_t *packet, uint16_t size){ 139 140 static uint8_t config_options[] = { 1, 2, 150, 0}; // mtu = 48 141 142 uint8_t code = READ_L2CAP_SIGNALING_CODE( packet ); 143 uint8_t identifier = READ_L2CAP_SIGNALING_IDENTIFIER( packet ); 144 145 switch (channel->state) { 146 147 case L2CAP_STATE_WAIT_CONNECT_RSP: 148 switch (code){ 149 case CONNECTION_RESPONSE: 150 if ( READ_BT_16 (packet, L2CAP_SIGNALING_DATA_OFFSET+3) == 0){ 151 // successfull connection 152 channel->dest_cid = READ_BT_16(packet, L2CAP_SIGNALING_DATA_OFFSET + 0); 153 channel->sig_id = l2cap_next_sig_id(); 154 l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->sig_id, channel->dest_cid, 0, 4, &config_options); 155 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ_RSP; 156 } else { 157 //@TODO: implement failed 158 } 159 break; 160 //@TODO: implement other signaling packets 161 } 162 break; 163 164 case L2CAP_STATE_WAIT_CONFIG_REQ_RSP: 165 switch (code) { 166 case CONFIGURE_RESPONSE: 167 channel->state = L2CAP_STATE_WAIT_CONFIG_REQ; 168 break; 169 } 170 break; 171 172 case L2CAP_STATE_WAIT_CONFIG_REQ: 173 switch (code) { 174 case CONFIGURE_REQUEST: 175 176 // accept the other's configuration options 177 l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, identifier, channel->dest_cid, 0, 0, size - 16, &packet[16]); 178 179 channel->state = L2CAP_STATE_OPEN; 180 l2cap_emit_channel_opened(channel); 181 break; 182 } 183 break; 184 185 case L2CAP_STATE_WAIT_DISCONNECT: 186 switch (code) { 187 case DISCONNECTION_RESPONSE: 188 channel->state = L2CAP_STATE_CLOSED; 189 l2cap_emit_channel_closed(channel); 190 191 // discard channel 192 linked_list_remove(&l2cap_channels, (linked_item_t *) channel); 193 free (channel); 194 break; 195 } 196 break; 197 } 198 } 199 200 // notify client 201 void l2cap_emit_channel_opened(l2cap_channel_t *channel) { 202 uint8_t event[16]; 203 event[0] = HCI_EVENT_L2CAP_CHANNEL_OPENED; 204 event[1] = sizeof(event) - 2; 205 bt_flip_addr(&event[2], channel->address); 206 bt_store_16(event, 8, channel->handle); 207 bt_store_16(event, 10, channel->psm); 208 bt_store_16(event, 12, channel->source_cid); 209 bt_store_16(event, 14, channel->dest_cid); 210 socket_connection_send_packet(channel->connection, HCI_EVENT_PACKET, 0, event, sizeof(event)); 211 } 212 213 void l2cap_emit_channel_closed(l2cap_channel_t *channel) { 214 uint8_t event[4]; 215 event[0] = HCI_EVENT_L2CAP_CHANNEL_CLOSED; 216 event[1] = sizeof(event) - 2; 217 bt_store_16(event, 2, channel->source_cid); 218 socket_connection_send_packet(channel->connection, HCI_EVENT_PACKET, 0, event, sizeof(event)); 219 } 220 221 void l2cap_acl_handler( uint8_t *packet, uint16_t size ){ 222 223 // Get Channel ID and command code 224 uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet); 225 uint8_t code = READ_L2CAP_SIGNALING_CODE( packet ); 226 227 // Get Connection 228 hci_con_handle_t handle = READ_ACL_CONNECTION_HANDLE(packet); 229 230 // Signaling Packet? 231 if (channel_id == 1) { 232 233 if (code < 1 || code == 2 || code >= 8){ 234 // not for a particular channel 235 return; 236 } 237 238 // Get Signaling Identifier and potential destination CID 239 uint8_t sig_id = READ_L2CAP_SIGNALING_IDENTIFIER(packet); 240 uint16_t dest_cid = READ_BT_16(packet, L2CAP_SIGNALING_DATA_OFFSET); 241 242 // Find channel for this sig_id and connection handle 243 linked_item_t *it; 244 for (it = (linked_item_t *) l2cap_channels; it ; it = it->next){ 245 l2cap_channel_t * chan = (l2cap_channel_t *) it; 246 if (chan->handle == handle) { 247 if (code & 1) { 248 // match odd commands by previous signaling identifier 249 if (chan->sig_id == sig_id) { 250 l2cap_signaling_handler( chan, packet, size); 251 } 252 } else { 253 // match even commands by source channel id 254 if (chan->source_cid == dest_cid) { 255 l2cap_signaling_handler( chan, packet, size); 256 } 257 } 258 } 259 } 260 return; 261 } 262 263 // Find channel for this channel_id and connection handle 264 l2cap_channel_t * channel = l2cap_get_channel_for_source_cid(channel_id); 265 if (channel) { 266 socket_connection_send_packet(channel->connection, HCI_ACL_DATA_PACKET, 0, packet, size); 267 } 268 269 // forward to higher layers 270 (*data_packet_handler)(channel_id, packet, size); 271 } 272 273 274 void l2cap_send_internal(uint16_t source_cid, uint8_t *data, uint16_t len){ 275 // find channel for source_cid, construct l2cap packet and send 276 l2cap_channel_t * channel = l2cap_get_channel_for_source_cid(source_cid); 277 if (channel) { 278 // 0 - Connection handle : PB=10 : BC=00 279 bt_store_16(acl_buffer, 0, channel->handle | (2 << 12) | (0 << 14)); 280 // 2 - ACL length 281 bt_store_16(acl_buffer, 2, len + 4); 282 // 4 - L2CAP packet length 283 bt_store_16(acl_buffer, 4, len + 0); 284 // 6 - L2CAP channel DEST 285 bt_store_16(acl_buffer, 6, channel->dest_cid); 286 // 8 - data 287 memcpy(&acl_buffer[8], data, len); 288 // send 289 hci_send_acl_packet(acl_buffer, len+8); 290 } 291 } 292 293 294