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 MATTHIAS 24 * RINGWALD 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 "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 command; 72 bool invalid; 73 switch (packet_type){ 74 case ATT_DATA_PACKET: 75 // parse opcode 76 opcode = packet[0u]; 77 method = opcode & 0x03f; 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) == 0) || 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 if (packet[0] != L2CAP_EVENT_CAN_SEND_NOW) break; 87 can_send_now_pending = 0; 88 for (i = 0; i < ATT_MAX; i++){ 89 index = (att_round_robin + i) & 1u; 90 if (subscriptions[index].packet_handler && subscriptions[index].waiting_for_can_send){ 91 subscriptions[index].waiting_for_can_send = 0; 92 subscriptions[index].packet_handler(packet_type, handle, packet, size); 93 // fairness: prioritize next service 94 att_round_robin = (index + 1u) % ATT_MAX; 95 // stop if client cannot send anymore 96 if (!hci_can_send_acl_le_packet_now()) break; 97 } 98 } 99 // check if more can send now events are needed 100 if (!can_send_now_pending){ 101 for (i = 0; i < ATT_MAX; i++){ 102 if (subscriptions[i].packet_handler && subscriptions[i].waiting_for_can_send){ 103 can_send_now_pending = 1; 104 // note: con_handle is not used, so we can pass in anything 105 l2cap_request_can_send_fix_channel_now_event(0, L2CAP_CID_ATTRIBUTE_PROTOCOL); 106 break; 107 } 108 } 109 } 110 break; 111 default: 112 break; 113 } 114 } 115 116 /** 117 * @brief reset att dispatchter 118 * @param packet_hander for ATT client packets 119 */ 120 void att_dispatch_register_client(btstack_packet_handler_t packet_handler){ 121 subscriptions[ATT_CLIENT].packet_handler = packet_handler; 122 l2cap_register_fixed_channel(att_packet_handler, L2CAP_CID_ATTRIBUTE_PROTOCOL); 123 } 124 125 /** 126 * @brief reset att dispatchter 127 * @param packet_hander for ATT server packets 128 */ 129 void att_dispatch_register_server(btstack_packet_handler_t packet_handler){ 130 subscriptions[ATT_SERVER].packet_handler = packet_handler; 131 l2cap_register_fixed_channel(att_packet_handler, L2CAP_CID_ATTRIBUTE_PROTOCOL); 132 } 133 134 /** 135 * @brief can send packet for client 136 * @param handle 137 */ 138 int att_dispatch_client_can_send_now(hci_con_handle_t con_handle){ 139 return l2cap_can_send_fixed_channel_packet_now(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL); 140 } 141 142 /** 143 * @brief can send packet for server 144 * @param handle 145 */ 146 int att_dispatch_server_can_send_now(hci_con_handle_t con_handle){ 147 return l2cap_can_send_fixed_channel_packet_now(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL); 148 } 149 150 /** 151 * @brief Request emission of L2CAP_EVENT_CAN_SEND_NOW as soon as possible for client 152 * @note L2CAP_EVENT_CAN_SEND_NOW might be emitted during call to this function 153 * so packet handler should be ready to handle it 154 * @param con_handle 155 */ 156 void att_dispatch_client_request_can_send_now_event(hci_con_handle_t con_handle){ 157 subscriptions[ATT_CLIENT].waiting_for_can_send = 1; 158 if (!can_send_now_pending){ 159 can_send_now_pending = 1; 160 l2cap_request_can_send_fix_channel_now_event(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL); 161 } 162 } 163 164 /** 165 * @brief Request emission of L2CAP_EVENT_CAN_SEND_NOW as soon as possible for server 166 * @note L2CAP_EVENT_CAN_SEND_NOW might be emitted during call to this function 167 * so packet handler should be ready to handle it 168 * @param con_handle 169 */ 170 void att_dispatch_server_request_can_send_now_event(hci_con_handle_t con_handle){ 171 subscriptions[ATT_SERVER].waiting_for_can_send = 1; 172 if (!can_send_now_pending){ 173 can_send_now_pending = 1; 174 l2cap_request_can_send_fix_channel_now_event(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL); 175 } 176 } 177 178 static void emit_mtu_exchange_complete(btstack_packet_handler_t packet_handler, hci_con_handle_t con_handle, uint16_t new_mtu){ 179 if (!packet_handler) return; 180 uint8_t packet[6]; 181 packet[0] = ATT_EVENT_MTU_EXCHANGE_COMPLETE; 182 packet[1] = sizeof(packet) - 2u; 183 little_endian_store_16(packet, 2, con_handle); 184 little_endian_store_16(packet, 4, new_mtu); 185 packet_handler(HCI_EVENT_PACKET, con_handle, packet, 6); 186 } 187 188 void att_dispatch_server_mtu_exchanged(hci_con_handle_t con_handle, uint16_t new_mtu){ 189 emit_mtu_exchange_complete(subscriptions[ATT_CLIENT].packet_handler, con_handle, new_mtu); 190 } 191 192 void att_dispatch_client_mtu_exchanged(hci_con_handle_t con_handle, uint16_t new_mtu){ 193 emit_mtu_exchange_complete(subscriptions[ATT_SERVER].packet_handler, con_handle, new_mtu); 194 } 195