1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BLUEKITCHEN 24 * GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #define BTSTACK_FILE__ "att_dispatch.c" 39 40 41 /** 42 * Dispatcher for independent implementation of ATT client and server 43 */ 44 45 #include "ble/att_dispatch.h" 46 #include "ble/core.h" 47 #include "btstack_debug.h" 48 #include "l2cap.h" 49 #include "btstack_event.h" 50 51 #define ATT_SERVER 0u 52 #define ATT_CLIENT 1u 53 #define ATT_MAX 2u 54 55 struct { 56 btstack_packet_handler_t packet_handler; 57 bool waiting_for_can_send; 58 } subscriptions[ATT_MAX]; 59 60 // index of subscription that will get can send now first if waiting for it 61 static uint8_t att_round_robin; 62 63 // track can send now requests 64 static bool can_send_now_pending; 65 66 static void att_dispatch_handle_can_send_now(uint8_t *packet, uint16_t size){ 67 uint8_t i; 68 uint8_t index; 69 uint16_t l2cap_cid = l2cap_event_can_send_now_get_local_cid(packet); 70 #ifdef ENABLE_GATT_OVER_CLASSIC 71 if (l2cap_cid != L2CAP_CID_ATTRIBUTE_PROTOCOL){ 72 // lookup att_server in hci_connection for l2cap_cid 73 btstack_linked_list_iterator_t it; 74 hci_connections_get_iterator(&it); 75 while(btstack_linked_list_iterator_has_next(&it)) { 76 hci_connection_t *hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 77 att_server_t * att_server = &hci_connection->att_server; 78 if (att_server->l2cap_cid == l2cap_cid){ 79 for (i = 0u; i < ATT_MAX; i++) { 80 index = (att_round_robin + i) & 1u; 81 if (att_server->send_requests[index]) { 82 att_server->send_requests[index] = false; 83 // registered packet handlers from Unenhanced LE 84 subscriptions[index].packet_handler(HCI_EVENT_PACKET, l2cap_cid, packet, size); 85 // fairness: prioritize next service 86 att_round_robin = (index + 1u) % ATT_MAX; 87 // stop if client cannot send anymore 88 if (!l2cap_can_send_packet_now(l2cap_cid)) break; 89 } 90 } 91 // check if more can send now events are needed 92 bool send_request_pending = att_server->send_requests[ATT_CLIENT] 93 || att_server->send_requests[ATT_SERVER]; 94 if (send_request_pending){ 95 l2cap_request_can_send_now_event(att_server->l2cap_cid); 96 } 97 return; 98 } 99 } 100 } 101 #endif 102 can_send_now_pending = false; 103 for (i = 0u; i < ATT_MAX; i++){ 104 index = (att_round_robin + i) & 1u; 105 if ( (subscriptions[index].packet_handler != NULL) && subscriptions[index].waiting_for_can_send){ 106 subscriptions[index].waiting_for_can_send = false; 107 subscriptions[index].packet_handler(HCI_EVENT_PACKET, l2cap_cid, packet, size); 108 // fairness: prioritize next service 109 att_round_robin = (index + 1u) % ATT_MAX; 110 // stop if client cannot send anymore 111 if (!hci_can_send_acl_le_packet_now()) break; 112 } 113 } 114 // check if more can send now events are needed 115 if (!can_send_now_pending){ 116 for (i = 0u; i < ATT_MAX; i++){ 117 if ((subscriptions[i].packet_handler != NULL) && subscriptions[i].waiting_for_can_send){ 118 can_send_now_pending = true; 119 // note: con_handle is not used, so we can pass in anything 120 l2cap_request_can_send_fix_channel_now_event(0, L2CAP_CID_ATTRIBUTE_PROTOCOL); 121 break; 122 } 123 } 124 } 125 } 126 127 static void att_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 128 uint8_t opcode; 129 uint8_t method; 130 bool for_server; 131 bool invalid; 132 uint8_t index; 133 switch (packet_type){ 134 case ATT_DATA_PACKET: 135 // parse opcode 136 opcode = packet[0u]; 137 method = opcode & 0x03fu; 138 invalid = method > ATT_MULTIPLE_HANDLE_VALUE_NTF; 139 // odd PDUs are sent from server to client - even PDUs are sent from client to server, also let server handle invalid ones 140 for_server = ((method & 1u) == 0u) || invalid; 141 index = for_server ? ATT_SERVER : ATT_CLIENT; 142 if (!subscriptions[index].packet_handler) return; 143 subscriptions[index].packet_handler(packet_type, channel, packet, size); 144 break; 145 case HCI_EVENT_PACKET: 146 switch (hci_event_packet_get_type(packet)) { 147 case L2CAP_EVENT_CAN_SEND_NOW: 148 att_dispatch_handle_can_send_now(packet, size); 149 break; 150 default: 151 break; 152 } 153 break; 154 default: 155 break; 156 } 157 } 158 159 void att_dispatch_register_client(btstack_packet_handler_t packet_handler){ 160 subscriptions[ATT_CLIENT].packet_handler = packet_handler; 161 l2cap_register_fixed_channel(att_packet_handler, L2CAP_CID_ATTRIBUTE_PROTOCOL); 162 } 163 164 void att_dispatch_register_server(btstack_packet_handler_t packet_handler){ 165 subscriptions[ATT_SERVER].packet_handler = packet_handler; 166 l2cap_register_fixed_channel(att_packet_handler, L2CAP_CID_ATTRIBUTE_PROTOCOL); 167 } 168 169 #ifdef ENABLE_GATT_OVER_CLASSIC 170 static uint16_t att_dispatch_classic_get_l2cap_cid(hci_con_handle_t con_handle){ 171 // get l2cap_cid from att_server in hci_connection 172 hci_connection_t * hci_connection = hci_connection_for_handle(con_handle); 173 if (hci_connection != NULL) { 174 return hci_connection->att_server.l2cap_cid; 175 } else { 176 return 0; 177 } 178 } 179 #endif 180 181 182 static bool att_dispatch_can_send_now(hci_con_handle_t con_handle) { 183 #ifdef ENABLE_GATT_OVER_CLASSIC 184 uint16_t l2cap_cid = att_dispatch_classic_get_l2cap_cid(con_handle); 185 if (l2cap_cid != 0){ 186 return l2cap_can_send_packet_now(l2cap_cid); 187 } 188 #endif 189 return l2cap_can_send_fixed_channel_packet_now(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL); 190 } 191 192 bool att_dispatch_client_can_send_now(hci_con_handle_t con_handle){ 193 return att_dispatch_can_send_now(con_handle); 194 } 195 196 bool att_dispatch_server_can_send_now(hci_con_handle_t con_handle){ 197 return att_dispatch_can_send_now(con_handle); 198 } 199 200 static void att_dispatch_request_can_send_now_event(hci_con_handle_t con_handle, uint8_t type) { 201 #ifdef ENABLE_GATT_OVER_CLASSIC 202 hci_connection_t * hci_connection = hci_connection_for_handle(con_handle); 203 if (hci_connection != NULL) { 204 att_server_t * att_server = &hci_connection->att_server; 205 if (att_server->l2cap_cid != 0){ 206 bool send_request_pending = att_server->send_requests[ATT_CLIENT] 207 || att_server->send_requests[ATT_SERVER]; 208 att_server->send_requests[type] = true; 209 if (send_request_pending == false){ 210 l2cap_request_can_send_now_event(att_server->l2cap_cid); 211 } 212 return; 213 } 214 } 215 #endif 216 subscriptions[type].waiting_for_can_send = true; 217 if (can_send_now_pending == false) { 218 can_send_now_pending = true; 219 l2cap_request_can_send_fix_channel_now_event(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL); 220 } 221 } 222 223 void att_dispatch_client_request_can_send_now_event(hci_con_handle_t con_handle){ 224 att_dispatch_request_can_send_now_event(con_handle, ATT_CLIENT); 225 } 226 227 void att_dispatch_server_request_can_send_now_event(hci_con_handle_t con_handle){ 228 att_dispatch_request_can_send_now_event(con_handle, ATT_SERVER); 229 } 230 231 static void emit_mtu_exchange_complete(btstack_packet_handler_t packet_handler, hci_con_handle_t con_handle, uint16_t new_mtu){ 232 if (!packet_handler) return; 233 uint8_t packet[6]; 234 packet[0] = ATT_EVENT_MTU_EXCHANGE_COMPLETE; 235 packet[1] = sizeof(packet) - 2u; 236 little_endian_store_16(packet, 2, con_handle); 237 little_endian_store_16(packet, 4, new_mtu); 238 packet_handler(HCI_EVENT_PACKET, con_handle, packet, 6); 239 } 240 241 void att_dispatch_server_mtu_exchanged(hci_con_handle_t con_handle, uint16_t new_mtu){ 242 emit_mtu_exchange_complete(subscriptions[ATT_CLIENT].packet_handler, con_handle, new_mtu); 243 } 244 245 void att_dispatch_client_mtu_exchanged(hci_con_handle_t con_handle, uint16_t new_mtu){ 246 emit_mtu_exchange_complete(subscriptions[ATT_SERVER].packet_handler, con_handle, new_mtu); 247 } 248