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_packet_handler(uint8_t packet_type, uint16_t handle, uint8_t *packet, uint16_t size){ 67 uint8_t index; 68 uint8_t i; 69 uint8_t opcode; 70 uint8_t method; 71 bool for_server; 72 bool invalid; 73 switch (packet_type){ 74 case ATT_DATA_PACKET: 75 // parse opcode 76 opcode = packet[0u]; 77 method = opcode & 0x03fu; 78 invalid = method > ATT_MULTIPLE_HANDLE_VALUE_NTF; 79 // odd PDUs are sent from server to client - even PDUs are sent from client to server, also let server handle invalid ones 80 for_server = ((method & 1u) == 0u) || invalid; 81 index = for_server ? ATT_SERVER : ATT_CLIENT; 82 if (!subscriptions[index].packet_handler) return; 83 subscriptions[index].packet_handler(packet_type, handle, packet, size); 84 break; 85 case HCI_EVENT_PACKET: 86 switch (hci_event_packet_get_type(packet)) { 87 case L2CAP_EVENT_CAN_SEND_NOW: 88 can_send_now_pending = false; 89 for (i = 0u; i < ATT_MAX; i++){ 90 index = (att_round_robin + i) & 1u; 91 if ( (subscriptions[index].packet_handler != NULL) && subscriptions[index].waiting_for_can_send){ 92 subscriptions[index].waiting_for_can_send = false; 93 subscriptions[index].packet_handler(packet_type, handle, packet, size); 94 // fairness: prioritize next service 95 att_round_robin = (index + 1u) % ATT_MAX; 96 // stop if client cannot send anymore 97 if (!hci_can_send_acl_le_packet_now()) break; 98 } 99 } 100 // check if more can send now events are needed 101 if (!can_send_now_pending){ 102 for (i = 0u; i < ATT_MAX; i++){ 103 if ((subscriptions[i].packet_handler != NULL) && subscriptions[i].waiting_for_can_send){ 104 can_send_now_pending = true; 105 // note: con_handle is not used, so we can pass in anything 106 l2cap_request_can_send_fix_channel_now_event(0, L2CAP_CID_ATTRIBUTE_PROTOCOL); 107 break; 108 } 109 } 110 } 111 break; 112 default: 113 break; 114 } 115 break; 116 default: 117 break; 118 } 119 } 120 121 void att_dispatch_register_client(btstack_packet_handler_t packet_handler){ 122 subscriptions[ATT_CLIENT].packet_handler = packet_handler; 123 l2cap_register_fixed_channel(att_packet_handler, L2CAP_CID_ATTRIBUTE_PROTOCOL); 124 } 125 126 void att_dispatch_register_server(btstack_packet_handler_t packet_handler){ 127 subscriptions[ATT_SERVER].packet_handler = packet_handler; 128 l2cap_register_fixed_channel(att_packet_handler, L2CAP_CID_ATTRIBUTE_PROTOCOL); 129 } 130 131 #ifdef ENABLE_GATT_OVER_CLASSIC 132 static uint16_t att_dispatch_classic_get_l2cap_cid(hci_con_handle_t con_handle){ 133 // get l2cap_cid from att_server in hci_connection 134 hci_connection_t * hci_connection = hci_connection_for_handle(con_handle); 135 if (hci_connection != NULL) { 136 return hci_connection->att_server.l2cap_cid; 137 } else { 138 return 0; 139 } 140 } 141 #endif 142 143 144 static bool att_dispatch_can_send_now(hci_con_handle_t con_handle) { 145 #ifdef ENABLE_GATT_OVER_CLASSIC 146 uint16_t l2cap_cid = att_dispatch_classic_get_l2cap_cid(con_handle); 147 if (l2cap_cid != 0){ 148 return l2cap_can_send_packet_now(l2cap_cid); 149 } 150 #endif 151 return l2cap_can_send_fixed_channel_packet_now(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL); 152 } 153 154 bool att_dispatch_client_can_send_now(hci_con_handle_t con_handle){ 155 return att_dispatch_can_send_now(con_handle); 156 } 157 158 bool att_dispatch_server_can_send_now(hci_con_handle_t con_handle){ 159 return att_dispatch_can_send_now(con_handle); 160 } 161 162 static void att_dispatch_request_can_send_now_event(hci_con_handle_t con_handle, uint8_t type) { 163 #ifdef ENABLE_GATT_OVER_CLASSIC 164 hci_connection_t * hci_connection = hci_connection_for_handle(con_handle); 165 if (hci_connection != NULL) { 166 att_server_t * att_server = &hci_connection->att_server; 167 if (att_server->l2cap_cid != 0){ 168 bool send_request_pending = att_server->send_requests[ATT_CLIENT] 169 || att_server->send_requests[ATT_SERVER]; 170 att_server->send_requests[type] = true; 171 if (send_request_pending == false){ 172 l2cap_request_can_send_now_event(att_server->l2cap_cid); 173 } 174 return; 175 } 176 } 177 #endif 178 subscriptions[type].waiting_for_can_send = true; 179 if (can_send_now_pending == false) { 180 can_send_now_pending = true; 181 l2cap_request_can_send_fix_channel_now_event(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL); 182 } 183 } 184 185 void att_dispatch_client_request_can_send_now_event(hci_con_handle_t con_handle){ 186 att_dispatch_request_can_send_now_event(con_handle, ATT_CLIENT); 187 } 188 189 void att_dispatch_server_request_can_send_now_event(hci_con_handle_t con_handle){ 190 att_dispatch_request_can_send_now_event(con_handle, ATT_SERVER); 191 } 192 193 static void emit_mtu_exchange_complete(btstack_packet_handler_t packet_handler, hci_con_handle_t con_handle, uint16_t new_mtu){ 194 if (!packet_handler) return; 195 uint8_t packet[6]; 196 packet[0] = ATT_EVENT_MTU_EXCHANGE_COMPLETE; 197 packet[1] = sizeof(packet) - 2u; 198 little_endian_store_16(packet, 2, con_handle); 199 little_endian_store_16(packet, 4, new_mtu); 200 packet_handler(HCI_EVENT_PACKET, con_handle, packet, 6); 201 } 202 203 void att_dispatch_server_mtu_exchanged(hci_con_handle_t con_handle, uint16_t new_mtu){ 204 emit_mtu_exchange_complete(subscriptions[ATT_CLIENT].packet_handler, con_handle, new_mtu); 205 } 206 207 void att_dispatch_client_mtu_exchanged(hci_con_handle_t con_handle, uint16_t new_mtu){ 208 emit_mtu_exchange_complete(subscriptions[ATT_SERVER].packet_handler, con_handle, new_mtu); 209 } 210