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/*
* Copyright (C) 2014 BlueKitchen GmbH
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the copyright holders nor the names of
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
* 4. Any redistribution, use, or modification is done solely for
* personal benefit and not for any commercial purpose or for
* monetary gain.
*
* THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BLUEKITCHEN
* GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
* THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* Please inquire about commercial licensing options at
* contact@bluekitchen-gmbh.com
*
*/
#define BTSTACK_FILE__ "att_dispatch.c"
/**
* Dispatcher for independent implementation of ATT client and server
*/
#include "ble/att_dispatch.h"
#include "ble/core.h"
#include "btstack_debug.h"
#include "l2cap.h"
#include "btstack_event.h"
#define ATT_SERVER 0u
#define ATT_CLIENT 1u
#define ATT_MAX 2u
struct {
btstack_packet_handler_t packet_handler;
bool waiting_for_can_send;
} subscriptions[ATT_MAX];
// index of subscription that will get can send now first if waiting for it
static uint8_t att_round_robin;
// track can send now requests
static bool can_send_now_pending;
#ifdef ENABLE_GATT_OVER_CLASSIC
static att_server_t * att_dispatch_att_server_for_l2cap_cid(uint16_t l2cap_cid){
btstack_linked_list_iterator_t it;
hci_connections_get_iterator(&it);
while(btstack_linked_list_iterator_has_next(&it)) {
hci_connection_t *hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it);
att_server_t *att_server = &hci_connection->att_server;
if (att_server->l2cap_cid == l2cap_cid){
return att_server;
}
}
return NULL;
}
#endif
static void att_dispatch_handle_can_send_now(uint8_t *packet, uint16_t size){
uint8_t i;
uint8_t index;
uint16_t l2cap_cid = l2cap_event_can_send_now_get_local_cid(packet);
#ifdef ENABLE_GATT_OVER_CLASSIC
if (l2cap_cid != L2CAP_CID_ATTRIBUTE_PROTOCOL){
att_server_t * att_server = att_dispatch_att_server_for_l2cap_cid(l2cap_cid);
if (att_server != NULL){
for (i = 0u; i < ATT_MAX; i++) {
index = (att_round_robin + i) & 1u;
if (att_server->send_requests[index]) {
att_server->send_requests[index] = false;
// registered packet handlers from Unenhanced LE
subscriptions[index].packet_handler(HCI_EVENT_PACKET, l2cap_cid, packet, size);
// fairness: prioritize next service
att_round_robin = (index + 1u) % ATT_MAX;
// stop if client cannot send anymore
if (!l2cap_can_send_packet_now(l2cap_cid)) break;
}
}
// check if more can send now events are needed
bool send_request_pending = att_server->send_requests[ATT_CLIENT]
|| att_server->send_requests[ATT_SERVER];
if (send_request_pending){
l2cap_request_can_send_now_event(att_server->l2cap_cid);
}
return;
}
}
#endif
can_send_now_pending = false;
for (i = 0u; i < ATT_MAX; i++){
index = (att_round_robin + i) & 1u;
if ( (subscriptions[index].packet_handler != NULL) && subscriptions[index].waiting_for_can_send){
subscriptions[index].waiting_for_can_send = false;
subscriptions[index].packet_handler(HCI_EVENT_PACKET, l2cap_cid, packet, size);
// fairness: prioritize next service
att_round_robin = (index + 1u) % ATT_MAX;
// stop if client cannot send anymore
if (!hci_can_send_acl_le_packet_now()) break;
}
}
// check if more can send now events are needed
if (!can_send_now_pending){
for (i = 0u; i < ATT_MAX; i++){
if ((subscriptions[i].packet_handler != NULL) && subscriptions[i].waiting_for_can_send){
can_send_now_pending = true;
// note: con_handle is not used, so we can pass in anything
l2cap_request_can_send_fix_channel_now_event(0, L2CAP_CID_ATTRIBUTE_PROTOCOL);
break;
}
}
}
}
static void att_dispatch_handle_att_pdu(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
uint8_t index;
uint8_t opcode;
uint8_t method;
bool for_server;
bool invalid;
// parse opcode
opcode = packet[0u];
method = opcode & 0x03fu;
invalid = method > ATT_MULTIPLE_HANDLE_VALUE_NTF;
// odd PDUs are sent from server to client - even PDUs are sent from client to server, also let server handle invalid ones
for_server = ((method & 1u) == 0u) || invalid;
index = for_server ? ATT_SERVER : ATT_CLIENT;
if (!subscriptions[index].packet_handler) return;
subscriptions[index].packet_handler(packet_type, channel, packet, size);
}
static void att_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
#ifdef ENABLE_GATT_OVER_CLASSIC
hci_connection_t * hci_connection;
att_server_t * att_server;
hci_con_handle_t con_handle;
bool outgoing_active;
uint8_t index;
#endif
#if defined(ENABLE_GATT_OVER_CLASSIC) || defined(ENABLE_GATT_OVER_EATT)
bd_addr_t address;
uint16_t l2cap_cid;
uint8_t status;
#endif
switch (packet_type){
case ATT_DATA_PACKET:
att_dispatch_handle_att_pdu(packet_type, channel, packet, size);
break;
#ifdef ENABLE_GATT_OVER_CLASSIC
case L2CAP_DATA_PACKET:
att_dispatch_handle_att_pdu(packet_type, channel, packet, size);
break;
#endif
case HCI_EVENT_PACKET:
switch (hci_event_packet_get_type(packet)) {
case L2CAP_EVENT_CAN_SEND_NOW:
att_dispatch_handle_can_send_now(packet, size);
break;
#ifdef ENABLE_GATT_OVER_CLASSIC
case L2CAP_EVENT_INCOMING_CONNECTION:
l2cap_event_incoming_connection_get_address(packet, address);
l2cap_cid = l2cap_event_incoming_connection_get_local_cid(packet);
// reject if outgoing l2cap connection active, L2CAP/TIM/BV-01-C
con_handle = l2cap_event_incoming_connection_get_handle(packet);
hci_connection = hci_connection_for_handle(con_handle);
btstack_assert(hci_connection != NULL);
outgoing_active = hci_connection->att_server.l2cap_cid != 0;
if (outgoing_active) {
hci_connection->att_server.incoming_connection_request = true;
l2cap_decline_connection(l2cap_cid);
log_info("Decline incoming connection from %s", bd_addr_to_str(address));
} else {
l2cap_accept_connection(l2cap_cid);
log_info("Accept incoming connection from %s", bd_addr_to_str(address));
}
break;
case L2CAP_EVENT_CHANNEL_OPENED:
// store l2cap_cid in att_server
status = l2cap_event_channel_opened_get_status(packet);
con_handle = l2cap_event_channel_opened_get_handle(packet);
hci_connection = hci_connection_for_handle(con_handle);
if (status == ERROR_CODE_SUCCESS){
btstack_assert(hci_connection != NULL);
hci_connection->att_server.l2cap_cid = l2cap_event_channel_opened_get_local_cid(packet);
} else {
if (hci_connection != NULL){
hci_connection->att_server.l2cap_cid = 0;
}
}
// dispatch to all roles
for (index = 0; index < ATT_MAX; index++){
if (subscriptions[index].packet_handler != NULL){
subscriptions[index].packet_handler(packet_type, channel, packet, size);
}
}
break;
case L2CAP_EVENT_CHANNEL_CLOSED:
// clear l2cap_cid in att_server
l2cap_cid = l2cap_event_channel_closed_get_local_cid(packet);
att_server = att_dispatch_att_server_for_l2cap_cid(l2cap_cid);
att_server->l2cap_cid = 0;
// dispatch to all roles
for (index = 0; index < ATT_MAX; index++){
if (subscriptions[index].packet_handler != NULL){
subscriptions[index].packet_handler(packet_type, channel, packet, size);
}
}
break;
#endif
default:
break;
}
break;
default:
break;
}
}
void att_dispatch_register_client(btstack_packet_handler_t packet_handler){
subscriptions[ATT_CLIENT].packet_handler = packet_handler;
l2cap_register_fixed_channel(att_packet_handler, L2CAP_CID_ATTRIBUTE_PROTOCOL);
}
void att_dispatch_register_server(btstack_packet_handler_t packet_handler){
subscriptions[ATT_SERVER].packet_handler = packet_handler;
l2cap_register_fixed_channel(att_packet_handler, L2CAP_CID_ATTRIBUTE_PROTOCOL);
}
#ifdef ENABLE_GATT_OVER_CLASSIC
static uint16_t att_dispatch_classic_get_l2cap_cid(hci_con_handle_t con_handle){
// get l2cap_cid from att_server in hci_connection
hci_connection_t * hci_connection = hci_connection_for_handle(con_handle);
if (hci_connection != NULL) {
return hci_connection->att_server.l2cap_cid;
} else {
return 0;
}
}
#endif
static bool att_dispatch_can_send_now(hci_con_handle_t con_handle) {
#ifdef ENABLE_GATT_OVER_CLASSIC
uint16_t l2cap_cid = att_dispatch_classic_get_l2cap_cid(con_handle);
if (l2cap_cid != 0){
return l2cap_can_send_packet_now(l2cap_cid);
}
#endif
return l2cap_can_send_fixed_channel_packet_now(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL);
}
bool att_dispatch_client_can_send_now(hci_con_handle_t con_handle){
return att_dispatch_can_send_now(con_handle);
}
bool att_dispatch_server_can_send_now(hci_con_handle_t con_handle){
return att_dispatch_can_send_now(con_handle);
}
static void att_dispatch_request_can_send_now_event(hci_con_handle_t con_handle, uint8_t type) {
#ifdef ENABLE_GATT_OVER_CLASSIC
hci_connection_t * hci_connection = hci_connection_for_handle(con_handle);
if (hci_connection != NULL) {
att_server_t * att_server = &hci_connection->att_server;
if (att_server->l2cap_cid != 0){
bool send_request_pending = att_server->send_requests[ATT_CLIENT]
|| att_server->send_requests[ATT_SERVER];
att_server->send_requests[type] = true;
if (send_request_pending == false){
l2cap_request_can_send_now_event(att_server->l2cap_cid);
}
return;
}
}
#endif
subscriptions[type].waiting_for_can_send = true;
if (can_send_now_pending == false) {
can_send_now_pending = true;
l2cap_request_can_send_fix_channel_now_event(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL);
}
}
void att_dispatch_client_request_can_send_now_event(hci_con_handle_t con_handle){
att_dispatch_request_can_send_now_event(con_handle, ATT_CLIENT);
}
void att_dispatch_server_request_can_send_now_event(hci_con_handle_t con_handle){
att_dispatch_request_can_send_now_event(con_handle, ATT_SERVER);
}
static void emit_mtu_exchange_complete(btstack_packet_handler_t packet_handler, hci_con_handle_t con_handle, uint16_t new_mtu){
if (!packet_handler) return;
uint8_t packet[6];
packet[0] = ATT_EVENT_MTU_EXCHANGE_COMPLETE;
packet[1] = sizeof(packet) - 2u;
little_endian_store_16(packet, 2, con_handle);
little_endian_store_16(packet, 4, new_mtu);
packet_handler(HCI_EVENT_PACKET, con_handle, packet, 6);
}
void att_dispatch_server_mtu_exchanged(hci_con_handle_t con_handle, uint16_t new_mtu){
emit_mtu_exchange_complete(subscriptions[ATT_CLIENT].packet_handler, con_handle, new_mtu);
}
void att_dispatch_client_mtu_exchanged(hci_con_handle_t con_handle, uint16_t new_mtu){
emit_mtu_exchange_complete(subscriptions[ATT_SERVER].packet_handler, con_handle, new_mtu);
}
#ifdef ENABLE_GATT_OVER_CLASSIC
void att_dispatch_classic_register_service(void){
l2cap_register_service(&att_packet_handler, PSM_ATT, 0xffff, gap_get_security_level());
}
uint8_t att_dispatch_classic_connect(bd_addr_t address, uint16_t l2cap_psm, uint16_t *out_cid) {
uint16_t l2cap_cid;
uint8_t status = l2cap_create_channel(&att_packet_handler, address, l2cap_psm, 0xffff, &l2cap_cid);
// store l2cap_cid in hci_connection
if (status == ERROR_CODE_SUCCESS){
hci_connection_t * hci_connection = hci_connection_for_bd_addr_and_type(address, BD_ADDR_TYPE_ACL);
if (hci_connection != NULL) {
hci_connection->att_server.l2cap_cid = l2cap_cid;
hci_connection->att_server.incoming_connection_request = false;
}
}
*out_cid = l2cap_cid;
return status;
}
#endif
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