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 50 #define ATT_SERVER 0 51 #define ATT_CLIENT 1 52 #define ATT_MAX 2 53 54 struct { 55 btstack_packet_handler_t packet_handler; 56 uint8_t waiting_for_can_send; 57 } subscriptions[ATT_MAX]; 58 59 // index of subscription that will get can send now first if waiting for it 60 static uint8_t att_round_robin; 61 62 // track can send now requests 63 static uint8_t can_send_now_pending; 64 65 static void att_packet_handler(uint8_t packet_type, uint16_t handle, uint8_t *packet, uint16_t size){ 66 uint8_t index; 67 uint8_t i; 68 uint8_t opcode; 69 uint8_t method; 70 bool for_server; 71 bool invalid; 72 switch (packet_type){ 73 case ATT_DATA_PACKET: 74 // parse opcode 75 opcode = packet[0u]; 76 method = opcode & 0x03f; 77 invalid = method > ATT_MULTIPLE_HANDLE_VALUE_NTF; 78 // odd PDUs are sent from server to client - even PDUs are sent from client to server, also let server handle invalid ones 79 for_server = ((method & 1u) == 0) || invalid; 80 index = for_server ? ATT_SERVER : ATT_CLIENT; 81 if (!subscriptions[index].packet_handler) return; 82 subscriptions[index].packet_handler(packet_type, handle, packet, size); 83 break; 84 case HCI_EVENT_PACKET: 85 if (packet[0] != L2CAP_EVENT_CAN_SEND_NOW) break; 86 can_send_now_pending = 0; 87 for (i = 0; i < ATT_MAX; i++){ 88 index = (att_round_robin + i) & 1u; 89 if (subscriptions[index].packet_handler && subscriptions[index].waiting_for_can_send){ 90 subscriptions[index].waiting_for_can_send = 0; 91 subscriptions[index].packet_handler(packet_type, handle, packet, size); 92 // fairness: prioritize next service 93 att_round_robin = (index + 1u) % ATT_MAX; 94 // stop if client cannot send anymore 95 if (!hci_can_send_acl_le_packet_now()) break; 96 } 97 } 98 // check if more can send now events are needed 99 if (!can_send_now_pending){ 100 for (i = 0; i < ATT_MAX; i++){ 101 if (subscriptions[i].packet_handler && subscriptions[i].waiting_for_can_send){ 102 can_send_now_pending = 1; 103 // note: con_handle is not used, so we can pass in anything 104 l2cap_request_can_send_fix_channel_now_event(0, L2CAP_CID_ATTRIBUTE_PROTOCOL); 105 break; 106 } 107 } 108 } 109 break; 110 default: 111 break; 112 } 113 } 114 115 /** 116 * @brief reset att dispatchter 117 * @param packet_hander for ATT client packets 118 */ 119 void att_dispatch_register_client(btstack_packet_handler_t packet_handler){ 120 subscriptions[ATT_CLIENT].packet_handler = packet_handler; 121 l2cap_register_fixed_channel(att_packet_handler, L2CAP_CID_ATTRIBUTE_PROTOCOL); 122 } 123 124 /** 125 * @brief reset att dispatchter 126 * @param packet_hander for ATT server packets 127 */ 128 void att_dispatch_register_server(btstack_packet_handler_t packet_handler){ 129 subscriptions[ATT_SERVER].packet_handler = packet_handler; 130 l2cap_register_fixed_channel(att_packet_handler, L2CAP_CID_ATTRIBUTE_PROTOCOL); 131 } 132 133 /** 134 * @brief can send packet for client 135 * @param handle 136 */ 137 int att_dispatch_client_can_send_now(hci_con_handle_t con_handle){ 138 return l2cap_can_send_fixed_channel_packet_now(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL); 139 } 140 141 /** 142 * @brief can send packet for server 143 * @param handle 144 */ 145 int att_dispatch_server_can_send_now(hci_con_handle_t con_handle){ 146 return l2cap_can_send_fixed_channel_packet_now(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL); 147 } 148 149 /** 150 * @brief Request emission of L2CAP_EVENT_CAN_SEND_NOW as soon as possible for client 151 * @note L2CAP_EVENT_CAN_SEND_NOW might be emitted during call to this function 152 * so packet handler should be ready to handle it 153 * @param con_handle 154 */ 155 void att_dispatch_client_request_can_send_now_event(hci_con_handle_t con_handle){ 156 subscriptions[ATT_CLIENT].waiting_for_can_send = 1; 157 if (!can_send_now_pending){ 158 can_send_now_pending = 1; 159 l2cap_request_can_send_fix_channel_now_event(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL); 160 } 161 } 162 163 /** 164 * @brief Request emission of L2CAP_EVENT_CAN_SEND_NOW as soon as possible for server 165 * @note L2CAP_EVENT_CAN_SEND_NOW might be emitted during call to this function 166 * so packet handler should be ready to handle it 167 * @param con_handle 168 */ 169 void att_dispatch_server_request_can_send_now_event(hci_con_handle_t con_handle){ 170 subscriptions[ATT_SERVER].waiting_for_can_send = 1; 171 if (!can_send_now_pending){ 172 can_send_now_pending = 1; 173 l2cap_request_can_send_fix_channel_now_event(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL); 174 } 175 } 176 177 static void emit_mtu_exchange_complete(btstack_packet_handler_t packet_handler, hci_con_handle_t con_handle, uint16_t new_mtu){ 178 if (!packet_handler) return; 179 uint8_t packet[6]; 180 packet[0] = ATT_EVENT_MTU_EXCHANGE_COMPLETE; 181 packet[1] = sizeof(packet) - 2u; 182 little_endian_store_16(packet, 2, con_handle); 183 little_endian_store_16(packet, 4, new_mtu); 184 packet_handler(HCI_EVENT_PACKET, con_handle, packet, 6); 185 } 186 187 void att_dispatch_server_mtu_exchanged(hci_con_handle_t con_handle, uint16_t new_mtu){ 188 emit_mtu_exchange_complete(subscriptions[ATT_CLIENT].packet_handler, con_handle, new_mtu); 189 } 190 191 void att_dispatch_client_mtu_exchanged(hci_con_handle_t con_handle, uint16_t new_mtu){ 192 emit_mtu_exchange_complete(subscriptions[ATT_SERVER].packet_handler, con_handle, new_mtu); 193 } 194