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 0u 51 #define ATT_CLIENT 1u 52 #define ATT_MAX 2u 53 54 struct { 55 btstack_packet_handler_t packet_handler; 56 bool 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 bool 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 & 0x03fu; 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) == 0u) || 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 = false; 87 for (i = 0u; i < ATT_MAX; i++){ 88 index = (att_round_robin + i) & 1u; 89 if ( (subscriptions[index].packet_handler != NULL) && subscriptions[index].waiting_for_can_send){ 90 subscriptions[index].waiting_for_can_send = false; 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 = 0u; i < ATT_MAX; i++){ 101 if ((subscriptions[i].packet_handler != NULL) && subscriptions[i].waiting_for_can_send){ 102 can_send_now_pending = true; 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 void att_dispatch_register_client(btstack_packet_handler_t packet_handler){ 116 subscriptions[ATT_CLIENT].packet_handler = packet_handler; 117 l2cap_register_fixed_channel(att_packet_handler, L2CAP_CID_ATTRIBUTE_PROTOCOL); 118 } 119 120 void att_dispatch_register_server(btstack_packet_handler_t packet_handler){ 121 subscriptions[ATT_SERVER].packet_handler = packet_handler; 122 l2cap_register_fixed_channel(att_packet_handler, L2CAP_CID_ATTRIBUTE_PROTOCOL); 123 } 124 125 int att_dispatch_client_can_send_now(hci_con_handle_t con_handle){ 126 return l2cap_can_send_fixed_channel_packet_now(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL); 127 } 128 129 int att_dispatch_server_can_send_now(hci_con_handle_t con_handle){ 130 return l2cap_can_send_fixed_channel_packet_now(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL); 131 } 132 133 void att_dispatch_client_request_can_send_now_event(hci_con_handle_t con_handle){ 134 subscriptions[ATT_CLIENT].waiting_for_can_send = true; 135 if (!can_send_now_pending){ 136 can_send_now_pending = true; 137 l2cap_request_can_send_fix_channel_now_event(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL); 138 } 139 } 140 141 void att_dispatch_server_request_can_send_now_event(hci_con_handle_t con_handle){ 142 subscriptions[ATT_SERVER].waiting_for_can_send = true; 143 if (!can_send_now_pending){ 144 can_send_now_pending = true; 145 l2cap_request_can_send_fix_channel_now_event(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL); 146 } 147 } 148 149 static void emit_mtu_exchange_complete(btstack_packet_handler_t packet_handler, hci_con_handle_t con_handle, uint16_t new_mtu){ 150 if (!packet_handler) return; 151 uint8_t packet[6]; 152 packet[0] = ATT_EVENT_MTU_EXCHANGE_COMPLETE; 153 packet[1] = sizeof(packet) - 2u; 154 little_endian_store_16(packet, 2, con_handle); 155 little_endian_store_16(packet, 4, new_mtu); 156 packet_handler(HCI_EVENT_PACKET, con_handle, packet, 6); 157 } 158 159 void att_dispatch_server_mtu_exchanged(hci_con_handle_t con_handle, uint16_t new_mtu){ 160 emit_mtu_exchange_complete(subscriptions[ATT_CLIENT].packet_handler, con_handle, new_mtu); 161 } 162 163 void att_dispatch_client_mtu_exchanged(hci_con_handle_t con_handle, uint16_t new_mtu){ 164 emit_mtu_exchange_complete(subscriptions[ATT_SERVER].packet_handler, con_handle, new_mtu); 165 } 166