/*
* 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 MATTHIAS
* RINGWALD 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
*
*/
/*
* l2cap.c
*
* Logical Link Control and Adaption Protocl (L2CAP)
*
* Created by Matthias Ringwald on 5/16/09.
*/
#include "l2cap.h"
#include "hci.h"
#include "hci_dump.h"
#include "btstack_debug.h"
#include "btstack_memory.h"
#include <stdarg.h>
#include <string.h>
#include <stdio.h>
// nr of buffered acl packets in outgoing queue to get max performance
#define NR_BUFFERED_ACL_PACKETS 3
// used to cache l2cap rejects, echo, and informational requests
#define NR_PENDING_SIGNALING_RESPONSES 3
// offsets for L2CAP SIGNALING COMMANDS
#define L2CAP_SIGNALING_COMMAND_CODE_OFFSET 0
#define L2CAP_SIGNALING_COMMAND_SIGID_OFFSET 1
#define L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET 2
#define L2CAP_SIGNALING_COMMAND_DATA_OFFSET 4
// internal table
#define L2CAP_FIXED_CHANNEL_TABLE_INDEX_ATTRIBUTE_PROTOCOL 0
#define L2CAP_FIXED_CHANNEL_TABLE_INDEX_SECURITY_MANAGER_PROTOCOL 1
#define L2CAP_FIXED_CHANNEL_TABLE_INDEX_CONNECTIONLESS_CHANNEL 2
#define L2CAP_FIXED_CHANNEL_TABLE_SIZE (L2CAP_FIXED_CHANNEL_TABLE_INDEX_CONNECTIONLESS_CHANNEL+1)
// prototypes
static void l2cap_finialize_channel_close(l2cap_channel_t *channel);
static inline l2cap_service_t * l2cap_get_service(uint16_t psm);
static void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status);
static void l2cap_emit_can_send_now(btstack_packet_handler_t packet_handler, uint16_t channel);
static void l2cap_emit_channel_closed(l2cap_channel_t *channel);
static void l2cap_emit_connection_request(l2cap_channel_t *channel);
static int l2cap_channel_ready_for_open(l2cap_channel_t *channel);
static void l2cap_hci_event_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
static void l2cap_acl_handler(uint8_t packet_type, uint8_t *packet, uint16_t size );
typedef struct l2cap_fixed_channel {
btstack_packet_handler_t callback;
uint8_t waiting_for_can_send_now;
} l2cap_fixed_channel_t;
static btstack_linked_list_t l2cap_channels;
static btstack_linked_list_t l2cap_services;
static btstack_linked_list_t l2cap_le_channels;
static btstack_linked_list_t l2cap_le_services;
// used to cache l2cap rejects, echo, and informational requests
static l2cap_signaling_response_t signaling_responses[NR_PENDING_SIGNALING_RESPONSES];
static int signaling_responses_pending;
static uint8_t require_security_level2_for_outgoing_sdp;
static btstack_packet_callback_registration_t hci_event_callback_registration;
static btstack_packet_handler_t l2cap_event_packet_handler;
static l2cap_fixed_channel_t fixed_channels[L2CAP_FIXED_CHANNEL_TABLE_SIZE];
static uint16_t l2cap_fixed_channel_table_channel_id_for_index(int index){
switch (index){
case L2CAP_FIXED_CHANNEL_TABLE_INDEX_ATTRIBUTE_PROTOCOL:
return L2CAP_CID_ATTRIBUTE_PROTOCOL;
case L2CAP_FIXED_CHANNEL_TABLE_INDEX_SECURITY_MANAGER_PROTOCOL:
return L2CAP_CID_SECURITY_MANAGER_PROTOCOL;
case L2CAP_FIXED_CHANNEL_TABLE_INDEX_CONNECTIONLESS_CHANNEL:
return L2CAP_CID_CONNECTIONLESS_CHANNEL;
default:
return 0;
}
}
static int l2cap_fixed_channel_table_index_for_channel_id(uint16_t channel_id){
switch (channel_id){
case L2CAP_CID_ATTRIBUTE_PROTOCOL:
return L2CAP_FIXED_CHANNEL_TABLE_INDEX_ATTRIBUTE_PROTOCOL;
case L2CAP_CID_SECURITY_MANAGER_PROTOCOL:
return L2CAP_FIXED_CHANNEL_TABLE_INDEX_SECURITY_MANAGER_PROTOCOL;
case L2CAP_CID_CONNECTIONLESS_CHANNEL:
return L2CAP_FIXED_CHANNEL_TABLE_INDEX_CONNECTIONLESS_CHANNEL;
default:
return -1;
}
}
static int l2cap_fixed_channel_table_index_is_le(int index){
if (index == L2CAP_CID_CONNECTIONLESS_CHANNEL) return 0;
return 1;
}
void l2cap_init(void){
signaling_responses_pending = 0;
l2cap_channels = NULL;
l2cap_services = NULL;
l2cap_le_services = NULL;
l2cap_le_channels = NULL;
l2cap_event_packet_handler = NULL;
memset(fixed_channels, 0, sizeof(fixed_channels));
require_security_level2_for_outgoing_sdp = 0;
//
// register callback with HCI
//
hci_event_callback_registration.callback = &l2cap_hci_event_handler;
hci_add_event_handler(&hci_event_callback_registration);
hci_register_acl_packet_handler(&l2cap_acl_handler);
hci_connectable_control(0); // no services yet
}
void l2cap_register_packet_handler(void (*handler)(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size)){
l2cap_event_packet_handler = handler;
}
static void l2cap_dispatch_to_channel(l2cap_channel_t *channel, uint8_t type, uint8_t * data, uint16_t size){
(* (channel->packet_handler))(type, channel->local_cid, data, size);
}
void l2cap_emit_channel_opened(l2cap_channel_t *channel, uint8_t status) {
log_info("L2CAP_EVENT_CHANNEL_OPENED status 0x%x addr %s handle 0x%x psm 0x%x local_cid 0x%x remote_cid 0x%x local_mtu %u, remote_mtu %u, flush_timeout %u",
status, bd_addr_to_str(channel->address), channel->handle, channel->psm,
channel->local_cid, channel->remote_cid, channel->local_mtu, channel->remote_mtu, channel->flush_timeout);
uint8_t event[23];
event[0] = L2CAP_EVENT_CHANNEL_OPENED;
event[1] = sizeof(event) - 2;
event[2] = status;
reverse_bd_addr(channel->address, &event[3]);
little_endian_store_16(event, 9, channel->handle);
little_endian_store_16(event, 11, channel->psm);
little_endian_store_16(event, 13, channel->local_cid);
little_endian_store_16(event, 15, channel->remote_cid);
little_endian_store_16(event, 17, channel->local_mtu);
little_endian_store_16(event, 19, channel->remote_mtu);
little_endian_store_16(event, 21, channel->flush_timeout);
hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
l2cap_dispatch_to_channel(channel, HCI_EVENT_PACKET, event, sizeof(event));
// if channel opened successfully, also send can send now if possible
if (status) return;
if (hci_can_send_acl_packet_now(channel->handle)){
l2cap_emit_can_send_now(channel->packet_handler, channel->local_cid);
} else {
channel->waiting_for_can_send_now = 1;
}
}
void l2cap_emit_channel_closed(l2cap_channel_t *channel) {
log_info("L2CAP_EVENT_CHANNEL_CLOSED local_cid 0x%x", channel->local_cid);
uint8_t event[4];
event[0] = L2CAP_EVENT_CHANNEL_CLOSED;
event[1] = sizeof(event) - 2;
little_endian_store_16(event, 2, channel->local_cid);
hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
l2cap_dispatch_to_channel(channel, HCI_EVENT_PACKET, event, sizeof(event));
}
void l2cap_emit_connection_request(l2cap_channel_t *channel) {
log_info("L2CAP_EVENT_INCOMING_CONNECTION addr %s handle 0x%x psm 0x%x local_cid 0x%x remote_cid 0x%x",
bd_addr_to_str(channel->address), channel->handle, channel->psm, channel->local_cid, channel->remote_cid);
uint8_t event[16];
event[0] = L2CAP_EVENT_INCOMING_CONNECTION;
event[1] = sizeof(event) - 2;
reverse_bd_addr(channel->address, &event[2]);
little_endian_store_16(event, 8, channel->handle);
little_endian_store_16(event, 10, channel->psm);
little_endian_store_16(event, 12, channel->local_cid);
little_endian_store_16(event, 14, channel->remote_cid);
hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
l2cap_dispatch_to_channel(channel, HCI_EVENT_PACKET, event, sizeof(event));
}
static void l2cap_emit_can_send_now(btstack_packet_handler_t packet_handler, uint16_t channel) {
log_info("L2CAP_EVENT_CHANNEL_CAN_SEND_NOW local_cid 0x%x", channel);
uint8_t event[4];
event[0] = L2CAP_EVENT_CAN_SEND_NOW;
event[1] = sizeof(event) - 2;
little_endian_store_16(event, 2, channel);
hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
packet_handler(HCI_EVENT_PACKET, channel, event, sizeof(event));
}
static void l2cap_emit_connection_parameter_update_response(uint16_t handle, uint16_t result){
uint8_t event[6];
event[0] = L2CAP_EVENT_CONNECTION_PARAMETER_UPDATE_RESPONSE;
event[1] = 4;
little_endian_store_16(event, 2, handle);
little_endian_store_16(event, 4, result);
hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
if (!l2cap_event_packet_handler) return;
(*l2cap_event_packet_handler)(HCI_EVENT_PACKET, 0, event, sizeof(event));
}
static l2cap_channel_t * l2cap_get_channel_for_local_cid(uint16_t local_cid){
btstack_linked_list_iterator_t it;
btstack_linked_list_iterator_init(&it, &l2cap_channels);
while (btstack_linked_list_iterator_has_next(&it)){
l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it);
if ( channel->local_cid == local_cid) {
return channel;
}
}
return NULL;
}
int l2cap_can_send_packet_now(uint16_t local_cid){
l2cap_channel_t *channel = l2cap_get_channel_for_local_cid(local_cid);
if (!channel) return 0;
int can_send = hci_can_send_acl_packet_now(channel->handle);
if (!can_send){
channel->waiting_for_can_send_now = 1;
}
return can_send;
}
int l2cap_can_send_prepared_packet_now(uint16_t local_cid){
l2cap_channel_t *channel = l2cap_get_channel_for_local_cid(local_cid);
if (!channel) return 0;
int can_send = hci_can_send_prepared_acl_packet_now(channel->handle);
if (!can_send){
channel->waiting_for_can_send_now = 1;
}
return can_send;
}
int l2cap_can_send_fixed_channel_packet_now(uint16_t handle, uint16_t channel_id){
int can_send = hci_can_send_acl_packet_now(handle);
if (!can_send){
int index = l2cap_fixed_channel_table_index_for_channel_id(channel_id);
if (index >= 0){
fixed_channels[index].waiting_for_can_send_now = 1;
}
}
return can_send;
}
uint16_t l2cap_get_remote_mtu_for_local_cid(uint16_t local_cid){
l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid);
if (channel) {
return channel->remote_mtu;
}
return 0;
}
static l2cap_channel_t * l2cap_channel_for_rtx_timer(btstack_timer_source_t * ts){
btstack_linked_list_iterator_t it;
btstack_linked_list_iterator_init(&it, &l2cap_channels);
while (btstack_linked_list_iterator_has_next(&it)){
l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it);
if ( &channel->rtx == ts) {
return channel;
}
}
return NULL;
}
static void l2cap_rtx_timeout(btstack_timer_source_t * ts){
l2cap_channel_t * channel = l2cap_channel_for_rtx_timer(ts);
if (!ts) return;
log_info("l2cap_rtx_timeout for local cid 0x%02x", channel->local_cid);
// "When terminating the channel, it is not necessary to send a L2CAP_DisconnectReq
// and enter WAIT_DISCONNECT state. Channels can be transitioned directly to the CLOSED state."
// notify client
l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_RESPONSE_RESULT_RTX_TIMEOUT);
// discard channel
// no need to stop timer here, it is removed from list during timer callback
btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel);
btstack_memory_l2cap_channel_free(channel);
}
static void l2cap_stop_rtx(l2cap_channel_t * channel){
log_info("l2cap_stop_rtx for local cid 0x%02x", channel->local_cid);
btstack_run_loop_remove_timer(&channel->rtx);
}
static void l2cap_start_rtx(l2cap_channel_t * channel){
l2cap_stop_rtx(channel);
log_info("l2cap_start_rtx for local cid 0x%02x", channel->local_cid);
btstack_run_loop_set_timer_handler(&channel->rtx, l2cap_rtx_timeout);
btstack_run_loop_set_timer(&channel->rtx, L2CAP_RTX_TIMEOUT_MS);
btstack_run_loop_add_timer(&channel->rtx);
}
static void l2cap_start_ertx(l2cap_channel_t * channel){
log_info("l2cap_start_ertx for local cid 0x%02x", channel->local_cid);
l2cap_stop_rtx(channel);
btstack_run_loop_set_timer_handler(&channel->rtx, l2cap_rtx_timeout);
btstack_run_loop_set_timer(&channel->rtx, L2CAP_ERTX_TIMEOUT_MS);
btstack_run_loop_add_timer(&channel->rtx);
}
void l2cap_require_security_level_2_for_outgoing_sdp(void){
require_security_level2_for_outgoing_sdp = 1;
}
static int l2cap_security_level_0_allowed_for_PSM(uint16_t psm){
return (psm == PSM_SDP) && (!require_security_level2_for_outgoing_sdp);
}
static int l2cap_send_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, ...){
if (!hci_can_send_acl_packet_now(handle)){
log_info("l2cap_send_signaling_packet, cannot send");
return BTSTACK_ACL_BUFFERS_FULL;
}
// log_info("l2cap_send_signaling_packet type %u", cmd);
hci_reserve_packet_buffer();
uint8_t *acl_buffer = hci_get_outgoing_packet_buffer();
va_list argptr;
va_start(argptr, identifier);
uint16_t len = l2cap_create_signaling_classic(acl_buffer, handle, cmd, identifier, argptr);
va_end(argptr);
// log_info("l2cap_send_signaling_packet con %u!", handle);
return hci_send_acl_packet_buffer(len);
}
#ifdef ENABLE_BLE
static int l2cap_send_le_signaling_packet(hci_con_handle_t handle, L2CAP_SIGNALING_COMMANDS cmd, uint8_t identifier, ...){
if (!hci_can_send_acl_packet_now(handle)){
log_info("l2cap_send_signaling_packet, cannot send");
return BTSTACK_ACL_BUFFERS_FULL;
}
// log_info("l2cap_send_signaling_packet type %u", cmd);
hci_reserve_packet_buffer();
uint8_t *acl_buffer = hci_get_outgoing_packet_buffer();
va_list argptr;
va_start(argptr, identifier);
uint16_t len = l2cap_create_signaling_le(acl_buffer, handle, cmd, identifier, argptr);
va_end(argptr);
// log_info("l2cap_send_signaling_packet con %u!", handle);
return hci_send_acl_packet_buffer(len);
}
#endif
uint8_t *l2cap_get_outgoing_buffer(void){
return hci_get_outgoing_packet_buffer() + COMPLETE_L2CAP_HEADER; // 8 bytes
}
int l2cap_reserve_packet_buffer(void){
return hci_reserve_packet_buffer();
}
void l2cap_release_packet_buffer(void){
hci_release_packet_buffer();
}
int l2cap_send_prepared(uint16_t local_cid, uint16_t len){
if (!hci_is_packet_buffer_reserved()){
log_error("l2cap_send_prepared called without reserving packet first");
return BTSTACK_ACL_BUFFERS_FULL;
}
l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid);
if (!channel) {
log_error("l2cap_send_prepared no channel for cid 0x%02x", local_cid);
return -1; // TODO: define error
}
if (!hci_can_send_prepared_acl_packet_now(channel->handle)){
log_info("l2cap_send_prepared cid 0x%02x, cannot send", local_cid);
return BTSTACK_ACL_BUFFERS_FULL;
}
log_debug("l2cap_send_prepared cid 0x%02x, handle %u, 1 credit used", local_cid, channel->handle);
uint8_t *acl_buffer = hci_get_outgoing_packet_buffer();
int pb = hci_non_flushable_packet_boundary_flag_supported() ? 0x00 : 0x02;
// 0 - Connection handle : PB=pb : BC=00
little_endian_store_16(acl_buffer, 0, channel->handle | (pb << 12) | (0 << 14));
// 2 - ACL length
little_endian_store_16(acl_buffer, 2, len + 4);
// 4 - L2CAP packet length
little_endian_store_16(acl_buffer, 4, len + 0);
// 6 - L2CAP channel DEST
little_endian_store_16(acl_buffer, 6, channel->remote_cid);
// send
int err = hci_send_acl_packet_buffer(len+8);
return err;
}
int l2cap_send_prepared_connectionless(uint16_t handle, uint16_t cid, uint16_t len){
if (!hci_is_packet_buffer_reserved()){
log_error("l2cap_send_prepared_connectionless called without reserving packet first");
return BTSTACK_ACL_BUFFERS_FULL;
}
if (!hci_can_send_prepared_acl_packet_now(handle)){
log_info("l2cap_send_prepared_connectionless handle 0x%02x, cid 0x%02x, cannot send", handle, cid);
return BTSTACK_ACL_BUFFERS_FULL;
}
log_debug("l2cap_send_prepared_connectionless handle %u, cid 0x%02x", handle, cid);
uint8_t *acl_buffer = hci_get_outgoing_packet_buffer();
int pb = hci_non_flushable_packet_boundary_flag_supported() ? 0x00 : 0x02;
// 0 - Connection handle : PB=pb : BC=00
little_endian_store_16(acl_buffer, 0, handle | (pb << 12) | (0 << 14));
// 2 - ACL length
little_endian_store_16(acl_buffer, 2, len + 4);
// 4 - L2CAP packet length
little_endian_store_16(acl_buffer, 4, len + 0);
// 6 - L2CAP channel DEST
little_endian_store_16(acl_buffer, 6, cid);
// send
int err = hci_send_acl_packet_buffer(len+8);
return err;
}
int l2cap_send(uint16_t local_cid, uint8_t *data, uint16_t len){
l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid);
if (!channel) {
log_error("l2cap_send no channel for cid 0x%02x", local_cid);
return -1; // TODO: define error
}
if (len > channel->remote_mtu){
log_error("l2cap_send cid 0x%02x, data length exceeds remote MTU.", local_cid);
return L2CAP_DATA_LEN_EXCEEDS_REMOTE_MTU;
}
if (!hci_can_send_acl_packet_now(channel->handle)){
log_info("l2cap_send cid 0x%02x, cannot send", local_cid);
return BTSTACK_ACL_BUFFERS_FULL;
}
hci_reserve_packet_buffer();
uint8_t *acl_buffer = hci_get_outgoing_packet_buffer();
memcpy(&acl_buffer[8], data, len);
return l2cap_send_prepared(local_cid, len);
}
int l2cap_send_connectionless(uint16_t handle, uint16_t cid, uint8_t *data, uint16_t len){
if (!hci_can_send_acl_packet_now(handle)){
log_info("l2cap_send cid 0x%02x, cannot send", cid);
return BTSTACK_ACL_BUFFERS_FULL;
}
hci_reserve_packet_buffer();
uint8_t *acl_buffer = hci_get_outgoing_packet_buffer();
memcpy(&acl_buffer[8], data, len);
return l2cap_send_prepared_connectionless(handle, cid, len);
}
int l2cap_send_echo_request(uint16_t handle, uint8_t *data, uint16_t len){
return l2cap_send_signaling_packet(handle, ECHO_REQUEST, 0x77, len, data);
}
static inline void channelStateVarSetFlag(l2cap_channel_t *channel, L2CAP_CHANNEL_STATE_VAR flag){
channel->state_var = (L2CAP_CHANNEL_STATE_VAR) (channel->state_var | flag);
}
static inline void channelStateVarClearFlag(l2cap_channel_t *channel, L2CAP_CHANNEL_STATE_VAR flag){
channel->state_var = (L2CAP_CHANNEL_STATE_VAR) (channel->state_var & ~flag);
}
// MARK: L2CAP_RUN
// process outstanding signaling tasks
static void l2cap_run(void){
// log_info("l2cap_run: entered");
// check pending signaling responses
while (signaling_responses_pending){
hci_con_handle_t handle = signaling_responses[0].handle;
if (!hci_can_send_acl_packet_now(handle)) break;
uint8_t sig_id = signaling_responses[0].sig_id;
uint16_t infoType = signaling_responses[0].data; // INFORMATION_REQUEST
uint16_t result = signaling_responses[0].data; // CONNECTION_REQUEST, COMMAND_REJECT
uint8_t response_code = signaling_responses[0].code;
// remove first item before sending (to avoid sending response mutliple times)
signaling_responses_pending--;
int i;
for (i=0; i < signaling_responses_pending; i++){
memcpy(&signaling_responses[i], &signaling_responses[i+1], sizeof(l2cap_signaling_response_t));
}
switch (response_code){
case CONNECTION_REQUEST:
l2cap_send_signaling_packet(handle, CONNECTION_RESPONSE, sig_id, 0, 0, result, 0);
// also disconnect if result is 0x0003 - security blocked
if (result == 0x0003){
hci_disconnect_security_block(handle);
}
break;
case ECHO_REQUEST:
l2cap_send_signaling_packet(handle, ECHO_RESPONSE, sig_id, 0, NULL);
break;
case INFORMATION_REQUEST:
switch (infoType){
case 1: { // Connectionless MTU
uint16_t connectionless_mtu = hci_max_acl_data_packet_length();
l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 0, sizeof(connectionless_mtu), &connectionless_mtu);
break;
}
case 2: { // Extended Features Supported
// extended features request supported, features: fixed channels, unicast connectionless data reception
uint32_t features = 0x280;
l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 0, sizeof(features), &features);
break;
}
case 3: { // Fixed Channels Supported
uint8_t map[8];
memset(map, 0, 8);
map[0] = 0x01; // L2CAP Signaling Channel (0x01) + Connectionless reception (0x02)
l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 0, sizeof(map), &map);
break;
}
default:
// all other types are not supported
l2cap_send_signaling_packet(handle, INFORMATION_RESPONSE, sig_id, infoType, 1, 0, NULL);
break;
}
break;
case COMMAND_REJECT:
l2cap_send_signaling_packet(handle, COMMAND_REJECT, sig_id, result, 0, NULL);
#ifdef ENABLE_BLE
case COMMAND_REJECT_LE:
l2cap_send_le_signaling_packet(handle, COMMAND_REJECT, sig_id, result, 0, NULL);
break;
#endif
default:
// should not happen
break;
}
}
uint8_t config_options[4];
btstack_linked_list_iterator_t it;
btstack_linked_list_iterator_init(&it, &l2cap_channels);
while (btstack_linked_list_iterator_has_next(&it)){
l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it);
// log_info("l2cap_run: channel %p, state %u, var 0x%02x", channel, channel->state, channel->state_var);
switch (channel->state){
case L2CAP_STATE_WAIT_INCOMING_SECURITY_LEVEL_UPDATE:
case L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT:
if (!hci_can_send_acl_packet_now(channel->handle)) break;
if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONN_RESP_PEND) {
channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONN_RESP_PEND);
l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid, 1, 0);
}
break;
case L2CAP_STATE_WILL_SEND_CREATE_CONNECTION:
if (!hci_can_send_command_packet_now()) break;
// send connection request - set state first
channel->state = L2CAP_STATE_WAIT_CONNECTION_COMPLETE;
// BD_ADDR, Packet_Type, Page_Scan_Repetition_Mode, Reserved, Clock_Offset, Allow_Role_Switch
hci_send_cmd(&hci_create_connection, channel->address, hci_usable_acl_packet_types(), 0, 0, 0, 1);
break;
case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE:
if (!hci_can_send_acl_packet_now(channel->handle)) break;
channel->state = L2CAP_STATE_INVALID;
l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid, channel->reason, 0);
// discard channel - l2cap_finialize_channel_close without sending l2cap close event
l2cap_stop_rtx(channel);
btstack_linked_list_iterator_remove(&it);
btstack_memory_l2cap_channel_free(channel);
break;
case L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT:
if (!hci_can_send_acl_packet_now(channel->handle)) break;
channel->state = L2CAP_STATE_CONFIG;
channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ);
l2cap_send_signaling_packet(channel->handle, CONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid, 0, 0);
break;
case L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST:
if (!hci_can_send_acl_packet_now(channel->handle)) break;
// success, start l2cap handshake
channel->local_sig_id = l2cap_next_sig_id();
channel->state = L2CAP_STATE_WAIT_CONNECT_RSP;
l2cap_send_signaling_packet( channel->handle, CONNECTION_REQUEST, channel->local_sig_id, channel->psm, channel->local_cid);
l2cap_start_rtx(channel);
break;
case L2CAP_STATE_CONFIG:
if (!hci_can_send_acl_packet_now(channel->handle)) break;
if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP){
uint16_t flags = 0;
channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP);
if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT) {
flags = 1;
} else {
channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP);
}
if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_INVALID){
l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, flags, L2CAP_CONF_RESULT_UNKNOWN_OPTIONS, 0, NULL);
} else if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_MTU){
config_options[0] = 1; // MTU
config_options[1] = 2; // len param
little_endian_store_16( (uint8_t*)&config_options, 2, channel->remote_mtu);
l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, flags, 0, 4, &config_options);
channelStateVarClearFlag(channel,L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_MTU);
} else {
l2cap_send_signaling_packet(channel->handle, CONFIGURE_RESPONSE, channel->remote_sig_id, channel->remote_cid, flags, 0, 0, NULL);
}
channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT);
}
else if (channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ){
channelStateVarClearFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ);
channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SENT_CONF_REQ);
channel->local_sig_id = l2cap_next_sig_id();
config_options[0] = 1; // MTU
config_options[1] = 2; // len param
little_endian_store_16( (uint8_t*)&config_options, 2, channel->local_mtu);
l2cap_send_signaling_packet(channel->handle, CONFIGURE_REQUEST, channel->local_sig_id, channel->remote_cid, 0, 4, &config_options);
l2cap_start_rtx(channel);
}
if (l2cap_channel_ready_for_open(channel)){
channel->state = L2CAP_STATE_OPEN;
l2cap_emit_channel_opened(channel, 0); // success
}
break;
case L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE:
if (!hci_can_send_acl_packet_now(channel->handle)) break;
channel->state = L2CAP_STATE_INVALID;
l2cap_send_signaling_packet( channel->handle, DISCONNECTION_RESPONSE, channel->remote_sig_id, channel->local_cid, channel->remote_cid);
// we don't start an RTX timer for a disconnect - there's no point in closing the channel if the other side doesn't respond :)
l2cap_finialize_channel_close(channel); // -- remove from list
break;
case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST:
if (!hci_can_send_acl_packet_now(channel->handle)) break;
channel->local_sig_id = l2cap_next_sig_id();
channel->state = L2CAP_STATE_WAIT_DISCONNECT;
l2cap_send_signaling_packet( channel->handle, DISCONNECTION_REQUEST, channel->local_sig_id, channel->remote_cid, channel->local_cid);
break;
default:
break;
}
}
#ifdef ENABLE_BLE
// send l2cap con paramter update if necessary
hci_connections_get_iterator(&it);
while(btstack_linked_list_iterator_has_next(&it)){
hci_connection_t * connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it);
if (connection->address_type != BD_ADDR_TYPE_LE_PUBLIC && connection->address_type != BD_ADDR_TYPE_LE_RANDOM) continue;
if (!hci_can_send_acl_packet_now(connection->con_handle)) continue;
switch (connection->le_con_parameter_update_state){
case CON_PARAMETER_UPDATE_SEND_REQUEST:
connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_NONE;
l2cap_send_le_signaling_packet(connection->con_handle, CONNECTION_PARAMETER_UPDATE_REQUEST, connection->le_con_param_update_identifier,
connection->le_conn_interval_min, connection->le_conn_interval_max, connection->le_conn_latency, connection->le_supervision_timeout);
break;
case CON_PARAMETER_UPDATE_SEND_RESPONSE:
connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_CHANGE_HCI_CON_PARAMETERS;
l2cap_send_le_signaling_packet(connection->con_handle, CONNECTION_PARAMETER_UPDATE_RESPONSE, connection->le_con_param_update_identifier, 0);
break;
case CON_PARAMETER_UPDATE_DENY:
connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_NONE;
l2cap_send_le_signaling_packet(connection->con_handle, CONNECTION_PARAMETER_UPDATE_RESPONSE, connection->le_con_param_update_identifier, 1);
break;
default:
break;
}
}
#endif
// log_info("l2cap_run: exit");
}
uint16_t l2cap_max_mtu(void){
return HCI_ACL_PAYLOAD_SIZE - L2CAP_HEADER_SIZE;
}
uint16_t l2cap_max_le_mtu(void){
return l2cap_max_mtu();
}
static void l2cap_handle_connection_complete(uint16_t handle, l2cap_channel_t * channel){
if (channel->state == L2CAP_STATE_WAIT_CONNECTION_COMPLETE || channel->state == L2CAP_STATE_WILL_SEND_CREATE_CONNECTION) {
log_info("l2cap_handle_connection_complete expected state");
// success, start l2cap handshake
channel->handle = handle;
// check remote SSP feature first
channel->state = L2CAP_STATE_WAIT_REMOTE_SUPPORTED_FEATURES;
}
}
static void l2cap_handle_remote_supported_features_received(l2cap_channel_t * channel){
if (channel->state != L2CAP_STATE_WAIT_REMOTE_SUPPORTED_FEATURES) return;
// we have been waiting for remote supported features, if both support SSP,
log_info("l2cap received remote supported features, sec_level_0_allowed for psm %u = %u", channel->psm, l2cap_security_level_0_allowed_for_PSM(channel->psm));
if (hci_ssp_supported_on_both_sides(channel->handle) && !l2cap_security_level_0_allowed_for_PSM(channel->psm)){
// request security level 2
channel->state = L2CAP_STATE_WAIT_OUTGOING_SECURITY_LEVEL_UPDATE;
gap_request_security_level(channel->handle, LEVEL_2);
return;
}
// fine, go ahead
channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST;
}
/**
* @brief Creates L2CAP channel to the PSM of a remote device with baseband address. A new baseband connection will be initiated if necessary.
* @param packet_handler
* @param address
* @param psm
* @param mtu
* @param local_cid
*/
uint8_t l2cap_create_channel(btstack_packet_handler_t channel_packet_handler, bd_addr_t address, uint16_t psm, uint16_t mtu, uint16_t * out_local_cid){
log_info("L2CAP_CREATE_CHANNEL addr %s psm 0x%x mtu %u", bd_addr_to_str(address), psm, mtu);
// alloc structure
l2cap_channel_t * chan = btstack_memory_l2cap_channel_get();
if (!chan) {
return BTSTACK_MEMORY_ALLOC_FAILED;
}
// Init memory (make valgrind happy)
memset(chan, 0, sizeof(l2cap_channel_t));
// limit local mtu to max acl packet length - l2cap header
if (mtu > l2cap_max_mtu()) {
mtu = l2cap_max_mtu();
}
// fill in
bd_addr_copy(chan->address, address);
chan->psm = psm;
chan->handle = 0;
chan->packet_handler = channel_packet_handler;
chan->remote_mtu = L2CAP_MINIMAL_MTU;
chan->local_mtu = mtu;
chan->local_cid = l2cap_next_local_cid();
// set initial state
chan->state = L2CAP_STATE_WILL_SEND_CREATE_CONNECTION;
chan->state_var = L2CAP_CHANNEL_STATE_VAR_NONE;
chan->remote_sig_id = L2CAP_SIG_ID_INVALID;
chan->local_sig_id = L2CAP_SIG_ID_INVALID;
chan->required_security_level = LEVEL_0;
// add to connections list
btstack_linked_list_add(&l2cap_channels, (btstack_linked_item_t *) chan);
// store local_cid
if (out_local_cid){
*out_local_cid = chan->local_cid;
}
// check if hci connection is already usable
hci_connection_t * conn = hci_connection_for_bd_addr_and_type(address, BD_ADDR_TYPE_CLASSIC);
if (conn){
log_info("l2cap_create_channel, hci connection already exists");
l2cap_handle_connection_complete(conn->con_handle, chan);
// check if remote supported fearures are already received
if (conn->bonding_flags & BONDING_RECEIVED_REMOTE_FEATURES) {
l2cap_handle_remote_supported_features_received(chan);
}
}
l2cap_run();
return 0;
}
void
l2cap_disconnect(uint16_t local_cid, uint8_t reason){
log_info("L2CAP_DISCONNECT local_cid 0x%x reason 0x%x", local_cid, reason);
// find channel for local_cid
l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid);
if (channel) {
channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST;
}
// process
l2cap_run();
}
static void l2cap_handle_connection_failed_for_addr(bd_addr_t address, uint8_t status){
btstack_linked_list_iterator_t it;
btstack_linked_list_iterator_init(&it, &l2cap_channels);
while (btstack_linked_list_iterator_has_next(&it)){
l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it);
if ( bd_addr_cmp( channel->address, address) != 0) continue;
// channel for this address found
switch (channel->state){
case L2CAP_STATE_WAIT_CONNECTION_COMPLETE:
case L2CAP_STATE_WILL_SEND_CREATE_CONNECTION:
// failure, forward error code
l2cap_emit_channel_opened(channel, status);
// discard channel
l2cap_stop_rtx(channel);
btstack_linked_list_iterator_remove(&it);
btstack_memory_l2cap_channel_free(channel);
break;
default:
break;
}
}
}
static void l2cap_handle_connection_success_for_addr(bd_addr_t address, hci_con_handle_t handle){
btstack_linked_list_iterator_t it;
btstack_linked_list_iterator_init(&it, &l2cap_channels);
while (btstack_linked_list_iterator_has_next(&it)){
l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it);
if ( ! bd_addr_cmp( channel->address, address) ){
l2cap_handle_connection_complete(handle, channel);
}
}
// process
l2cap_run();
}
static void l2cap_notify_channel_can_send(void){
btstack_linked_list_iterator_t it;
btstack_linked_list_iterator_init(&it, &l2cap_channels);
while (btstack_linked_list_iterator_has_next(&it)){
l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it);
if (!channel->waiting_for_can_send_now) continue;
if (!hci_can_send_acl_packet_now(channel->handle)) continue;
channel->waiting_for_can_send_now = 0;
l2cap_emit_can_send_now(channel->packet_handler, channel->local_cid);
}
int i;
for (i=0;i<L2CAP_FIXED_CHANNEL_TABLE_SIZE;i++){
if (!fixed_channels[i].callback) continue;
if (!fixed_channels[i].waiting_for_can_send_now) continue;
int can_send;
if (l2cap_fixed_channel_table_index_is_le(i)){
can_send = hci_can_send_acl_le_packet_now();
} else {
can_send = hci_can_send_acl_classic_packet_now();
}
if (!can_send) continue;
fixed_channels[i].waiting_for_can_send_now = 0;
l2cap_emit_can_send_now(fixed_channels[i].callback, l2cap_fixed_channel_table_channel_id_for_index(i));
}
}
static void l2cap_hci_event_handler(uint8_t packet_type, uint16_t cid, uint8_t *packet, uint16_t size){
bd_addr_t address;
hci_con_handle_t handle;
btstack_linked_list_iterator_t it;
int hci_con_used;
switch(packet[0]){
// handle connection complete events
case HCI_EVENT_CONNECTION_COMPLETE:
reverse_bd_addr(&packet[5], address);
if (packet[2] == 0){
handle = little_endian_read_16(packet, 3);
l2cap_handle_connection_success_for_addr(address, handle);
} else {
l2cap_handle_connection_failed_for_addr(address, packet[2]);
}
break;
// handle successful create connection cancel command
case HCI_EVENT_COMMAND_COMPLETE:
if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_create_connection_cancel)) {
if (packet[5] == 0){
reverse_bd_addr(&packet[6], address);
// CONNECTION TERMINATED BY LOCAL HOST (0X16)
l2cap_handle_connection_failed_for_addr(address, 0x16);
}
}
l2cap_run(); // try sending signaling packets first
break;
case HCI_EVENT_COMMAND_STATUS:
l2cap_run(); // try sending signaling packets first
break;
// handle disconnection complete events
case HCI_EVENT_DISCONNECTION_COMPLETE:
// send l2cap disconnect events for all channels on this handle and free them
handle = little_endian_read_16(packet, 3);
btstack_linked_list_iterator_init(&it, &l2cap_channels);
while (btstack_linked_list_iterator_has_next(&it)){
l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it);
if (channel->handle != handle) continue;
l2cap_emit_channel_closed(channel);
l2cap_stop_rtx(channel);
btstack_linked_list_iterator_remove(&it);
btstack_memory_l2cap_channel_free(channel);
}
break;
// Notify channel packet handler if they can send now
case DAEMON_EVENT_HCI_PACKET_SENT:
case HCI_EVENT_NUMBER_OF_COMPLETED_PACKETS:
l2cap_run(); // try sending signaling packets first
l2cap_notify_channel_can_send();
break;
// HCI Connection Timeouts
case L2CAP_EVENT_TIMEOUT_CHECK:
handle = little_endian_read_16(packet, 2);
if (gap_get_connection_type(handle) != GAP_CONNECTION_ACL) break;
if (hci_authentication_active_for_handle(handle)) break;
hci_con_used = 0;
btstack_linked_list_iterator_init(&it, &l2cap_channels);
while (btstack_linked_list_iterator_has_next(&it)){
l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it);
if (channel->handle != handle) continue;
hci_con_used = 1;
break;
}
if (hci_con_used) break;
if (!hci_can_send_command_packet_now()) break;
hci_send_cmd(&hci_disconnect, handle, 0x13); // remote closed connection
break;
case HCI_EVENT_READ_REMOTE_SUPPORTED_FEATURES_COMPLETE:
handle = little_endian_read_16(packet, 3);
btstack_linked_list_iterator_init(&it, &l2cap_channels);
while (btstack_linked_list_iterator_has_next(&it)){
l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it);
if (channel->handle != handle) continue;
l2cap_handle_remote_supported_features_received(channel);
break;
}
break;
case GAP_EVENT_SECURITY_LEVEL:
handle = little_endian_read_16(packet, 2);
log_info("l2cap - security level update");
btstack_linked_list_iterator_init(&it, &l2cap_channels);
while (btstack_linked_list_iterator_has_next(&it)){
l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it);
if (channel->handle != handle) continue;
log_info("l2cap - state %u", channel->state);
gap_security_level_t actual_level = (gap_security_level_t) packet[4];
gap_security_level_t required_level = channel->required_security_level;
switch (channel->state){
case L2CAP_STATE_WAIT_INCOMING_SECURITY_LEVEL_UPDATE:
if (actual_level >= required_level){
channel->state = L2CAP_STATE_WAIT_CLIENT_ACCEPT_OR_REJECT;
l2cap_emit_connection_request(channel);
} else {
channel->reason = 0x0003; // security block
channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE;
}
break;
case L2CAP_STATE_WAIT_OUTGOING_SECURITY_LEVEL_UPDATE:
if (actual_level >= required_level){
channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_REQUEST;
} else {
// disconnnect, authentication not good enough
hci_disconnect_security_block(handle);
}
break;
default:
break;
}
}
break;
default:
break;
}
l2cap_run();
}
static void l2cap_handle_disconnect_request(l2cap_channel_t *channel, uint16_t identifier){
channel->remote_sig_id = identifier;
channel->state = L2CAP_STATE_WILL_SEND_DISCONNECT_RESPONSE;
l2cap_run();
}
static void l2cap_register_signaling_response(hci_con_handle_t handle, uint8_t code, uint8_t sig_id, uint16_t data){
// Vol 3, Part A, 4.3: "The DCID and SCID fields shall be ignored when the result field indi- cates the connection was refused."
if (signaling_responses_pending < NR_PENDING_SIGNALING_RESPONSES) {
signaling_responses[signaling_responses_pending].handle = handle;
signaling_responses[signaling_responses_pending].code = code;
signaling_responses[signaling_responses_pending].sig_id = sig_id;
signaling_responses[signaling_responses_pending].data = data;
signaling_responses_pending++;
l2cap_run();
}
}
static void l2cap_handle_connection_request(hci_con_handle_t handle, uint8_t sig_id, uint16_t psm, uint16_t source_cid){
// log_info("l2cap_handle_connection_request for handle %u, psm %u cid 0x%02x", handle, psm, source_cid);
l2cap_service_t *service = l2cap_get_service(psm);
if (!service) {
// 0x0002 PSM not supported
l2cap_register_signaling_response(handle, CONNECTION_REQUEST, sig_id, 0x0002);
return;
}
hci_connection_t * hci_connection = hci_connection_for_handle( handle );
if (!hci_connection) {
//
log_error("no hci_connection for handle %u", handle);
return;
}
// alloc structure
// log_info("l2cap_handle_connection_request register channel");
l2cap_channel_t * channel = btstack_memory_l2cap_channel_get();
if (!channel){
// 0x0004 No resources available
l2cap_register_signaling_response(handle, CONNECTION_REQUEST, sig_id, 0x0004);
return;
}
// Init memory (make valgrind happy)
memset(channel, 0, sizeof(l2cap_channel_t));
// fill in
bd_addr_copy(channel->address, hci_connection->address);
channel->psm = psm;
channel->handle = handle;
channel->packet_handler = service->packet_handler;
channel->local_cid = l2cap_next_local_cid();
channel->remote_cid = source_cid;
channel->local_mtu = service->mtu;
channel->remote_mtu = L2CAP_DEFAULT_MTU;
channel->remote_sig_id = sig_id;
channel->required_security_level = service->required_security_level;
// limit local mtu to max acl packet length - l2cap header
if (channel->local_mtu > l2cap_max_mtu()) {
channel->local_mtu = l2cap_max_mtu();
}
// set initial state
channel->state = L2CAP_STATE_WAIT_INCOMING_SECURITY_LEVEL_UPDATE;
channel->state_var = L2CAP_CHANNEL_STATE_VAR_SEND_CONN_RESP_PEND;
// add to connections list
btstack_linked_list_add(&l2cap_channels, (btstack_linked_item_t *) channel);
// assert security requirements
gap_request_security_level(handle, channel->required_security_level);
}
void l2cap_accept_connection(uint16_t local_cid){
log_info("L2CAP_ACCEPT_CONNECTION local_cid 0x%x", local_cid);
l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(local_cid);
if (!channel) {
log_error("l2cap_accept_connection called but local_cid 0x%x not found", local_cid);
return;
}
channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_ACCEPT;
// process
l2cap_run();
}
void l2cap_decline_connection(uint16_t local_cid, uint8_t reason){
log_info("L2CAP_DECLINE_CONNECTION local_cid 0x%x, reason %x", local_cid, reason);
l2cap_channel_t * channel = l2cap_get_channel_for_local_cid( local_cid);
if (!channel) {
log_error( "l2cap_decline_connection called but local_cid 0x%x not found", local_cid);
return;
}
channel->state = L2CAP_STATE_WILL_SEND_CONNECTION_RESPONSE_DECLINE;
channel->reason = reason;
l2cap_run();
}
static void l2cap_signaling_handle_configure_request(l2cap_channel_t *channel, uint8_t *command){
channel->remote_sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET];
uint16_t flags = little_endian_read_16(command, 6);
if (flags & 1) {
channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT);
}
// accept the other's configuration options
uint16_t end_pos = 4 + little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET);
uint16_t pos = 8;
while (pos < end_pos){
uint8_t option_hint = command[pos] >> 7;
uint8_t option_type = command[pos] & 0x7f;
log_info("l2cap cid %u, hint %u, type %u", channel->local_cid, option_hint, option_type);
pos++;
uint8_t length = command[pos++];
// MTU { type(8): 1, len(8):2, MTU(16) }
if (option_type == 1 && length == 2){
channel->remote_mtu = little_endian_read_16(command, pos);
// log_info("l2cap cid 0x%02x, remote mtu %u", channel->local_cid, channel->remote_mtu);
channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_MTU);
}
// Flush timeout { type(8):2, len(8): 2, Flush Timeout(16)}
if (option_type == 2 && length == 2){
channel->flush_timeout = little_endian_read_16(command, pos);
}
// check for unknown options
if (option_hint == 0 && (option_type == 0 || option_type >= 0x07)){
log_info("l2cap cid %u, unknown options", channel->local_cid);
channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_INVALID);
}
pos += length;
}
}
static int l2cap_channel_ready_for_open(l2cap_channel_t *channel){
// log_info("l2cap_channel_ready_for_open 0x%02x", channel->state_var);
if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_RSP) == 0) return 0;
if ((channel->state_var & L2CAP_CHANNEL_STATE_VAR_SENT_CONF_RSP) == 0) return 0;
// addition check that fixes re-entrance issue causing l2cap event channel opened twice
if (channel->state == L2CAP_STATE_OPEN) return 0;
return 1;
}
static void l2cap_signaling_handler_channel(l2cap_channel_t *channel, uint8_t *command){
uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET];
uint8_t identifier = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET];
uint16_t result = 0;
log_info("L2CAP signaling handler code %u, state %u", code, channel->state);
// handle DISCONNECT REQUESTS seperately
if (code == DISCONNECTION_REQUEST){
switch (channel->state){
case L2CAP_STATE_CONFIG:
case L2CAP_STATE_OPEN:
case L2CAP_STATE_WILL_SEND_DISCONNECT_REQUEST:
case L2CAP_STATE_WAIT_DISCONNECT:
l2cap_handle_disconnect_request(channel, identifier);
break;
default:
// ignore in other states
break;
}
return;
}
// @STATEMACHINE(l2cap)
switch (channel->state) {
case L2CAP_STATE_WAIT_CONNECT_RSP:
switch (code){
case CONNECTION_RESPONSE:
l2cap_stop_rtx(channel);
result = little_endian_read_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4);
switch (result) {
case 0:
// successful connection
channel->remote_cid = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET);
channel->state = L2CAP_STATE_CONFIG;
channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ);
break;
case 1:
// connection pending. get some coffee, but start the ERTX
l2cap_start_ertx(channel);
break;
default:
// channel closed
channel->state = L2CAP_STATE_CLOSED;
// map l2cap connection response result to BTstack status enumeration
l2cap_emit_channel_opened(channel, L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result);
// drop link key if security block
if (L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL + result == L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_SECURITY){
hci_drop_link_key_for_bd_addr(channel->address);
}
// discard channel
btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel);
btstack_memory_l2cap_channel_free(channel);
break;
}
break;
default:
//@TODO: implement other signaling packets
break;
}
break;
case L2CAP_STATE_CONFIG:
result = little_endian_read_16 (command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+4);
switch (code) {
case CONFIGURE_REQUEST:
channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP);
l2cap_signaling_handle_configure_request(channel, command);
if (!(channel->state_var & L2CAP_CHANNEL_STATE_VAR_SEND_CONF_RSP_CONT)){
// only done if continuation not set
channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_REQ);
}
break;
case CONFIGURE_RESPONSE:
l2cap_stop_rtx(channel);
switch (result){
case 0: // success
channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_RCVD_CONF_RSP);
break;
case 4: // pending
l2cap_start_ertx(channel);
break;
default:
// retry on negative result
channelStateVarSetFlag(channel, L2CAP_CHANNEL_STATE_VAR_SEND_CONF_REQ);
break;
}
break;
default:
break;
}
if (l2cap_channel_ready_for_open(channel)){
// for open:
channel->state = L2CAP_STATE_OPEN;
l2cap_emit_channel_opened(channel, 0);
}
break;
case L2CAP_STATE_WAIT_DISCONNECT:
switch (code) {
case DISCONNECTION_RESPONSE:
l2cap_finialize_channel_close(channel);
break;
default:
//@TODO: implement other signaling packets
break;
}
break;
case L2CAP_STATE_CLOSED:
// @TODO handle incoming requests
break;
case L2CAP_STATE_OPEN:
//@TODO: implement other signaling packets, e.g. re-configure
break;
default:
break;
}
// log_info("new state %u", channel->state);
}
static void l2cap_signaling_handler_dispatch( hci_con_handle_t handle, uint8_t * command){
// get code, signalind identifier and command len
uint8_t code = command[L2CAP_SIGNALING_COMMAND_CODE_OFFSET];
uint8_t sig_id = command[L2CAP_SIGNALING_COMMAND_SIGID_OFFSET];
// not for a particular channel, and not CONNECTION_REQUEST, ECHO_[REQUEST|RESPONSE], INFORMATION_REQUEST
if (code < 1 || code == ECHO_RESPONSE || code > INFORMATION_REQUEST){
l2cap_register_signaling_response(handle, COMMAND_REJECT, sig_id, L2CAP_REJ_CMD_UNKNOWN);
return;
}
// general commands without an assigned channel
switch(code) {
case CONNECTION_REQUEST: {
uint16_t psm = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET);
uint16_t source_cid = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET+2);
l2cap_handle_connection_request(handle, sig_id, psm, source_cid);
return;
}
case ECHO_REQUEST:
l2cap_register_signaling_response(handle, code, sig_id, 0);
return;
case INFORMATION_REQUEST: {
uint16_t infoType = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET);
l2cap_register_signaling_response(handle, code, sig_id, infoType);
return;
}
default:
break;
}
// Get potential destination CID
uint16_t dest_cid = little_endian_read_16(command, L2CAP_SIGNALING_COMMAND_DATA_OFFSET);
// Find channel for this sig_id and connection handle
btstack_linked_list_iterator_t it;
btstack_linked_list_iterator_init(&it, &l2cap_channels);
while (btstack_linked_list_iterator_has_next(&it)){
l2cap_channel_t * channel = (l2cap_channel_t *) btstack_linked_list_iterator_next(&it);
if (channel->handle != handle) continue;
if (code & 1) {
// match odd commands (responses) by previous signaling identifier
if (channel->local_sig_id == sig_id) {
l2cap_signaling_handler_channel(channel, command);
break;
}
} else {
// match even commands (requests) by local channel id
if (channel->local_cid == dest_cid) {
l2cap_signaling_handler_channel(channel, command);
break;
}
}
}
}
static void l2cap_acl_handler(uint8_t packet_type, uint8_t *packet, uint16_t size ){
// Get Channel ID
uint16_t channel_id = READ_L2CAP_CHANNEL_ID(packet);
hci_con_handle_t handle = READ_ACL_CONNECTION_HANDLE(packet);
switch (channel_id) {
case L2CAP_CID_SIGNALING: {
uint16_t command_offset = 8;
while (command_offset < size) {
// handle signaling commands
l2cap_signaling_handler_dispatch(handle, &packet[command_offset]);
// increment command_offset
command_offset += L2CAP_SIGNALING_COMMAND_DATA_OFFSET + little_endian_read_16(packet, command_offset + L2CAP_SIGNALING_COMMAND_LENGTH_OFFSET);
}
break;
}
case L2CAP_CID_ATTRIBUTE_PROTOCOL:
if (fixed_channels[L2CAP_FIXED_CHANNEL_TABLE_INDEX_ATTRIBUTE_PROTOCOL].callback) {
(*fixed_channels[L2CAP_FIXED_CHANNEL_TABLE_INDEX_ATTRIBUTE_PROTOCOL].callback)(ATT_DATA_PACKET, handle, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER);
}
break;
case L2CAP_CID_SECURITY_MANAGER_PROTOCOL:
if (fixed_channels[L2CAP_FIXED_CHANNEL_TABLE_INDEX_SECURITY_MANAGER_PROTOCOL].callback) {
(*fixed_channels[L2CAP_FIXED_CHANNEL_TABLE_INDEX_SECURITY_MANAGER_PROTOCOL].callback)(SM_DATA_PACKET, handle, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER);
}
break;
case L2CAP_CID_CONNECTIONLESS_CHANNEL:
if (fixed_channels[L2CAP_FIXED_CHANNEL_TABLE_INDEX_CONNECTIONLESS_CHANNEL].callback) {
(*fixed_channels[L2CAP_FIXED_CHANNEL_TABLE_INDEX_CONNECTIONLESS_CHANNEL].callback)(UCD_DATA_PACKET, handle, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER);
}
break;
case L2CAP_CID_SIGNALING_LE: {
switch (packet[8]){
case CONNECTION_PARAMETER_UPDATE_RESPONSE: {
uint16_t result = little_endian_read_16(packet, 12);
l2cap_emit_connection_parameter_update_response(handle, result);
break;
}
case CONNECTION_PARAMETER_UPDATE_REQUEST: {
uint8_t event[10];
event[0] = L2CAP_EVENT_CONNECTION_PARAMETER_UPDATE_REQUEST;
event[1] = 8;
memcpy(&event[2], &packet[12], 8);
hci_connection_t * connection = hci_connection_for_handle(handle);
if (connection){
if (connection->role != HCI_ROLE_MASTER){
// reject command without notifying upper layer when not in master role
uint8_t sig_id = packet[COMPLETE_L2CAP_HEADER + 1];
l2cap_register_signaling_response(handle, COMMAND_REJECT_LE, sig_id, L2CAP_REJ_CMD_UNKNOWN);
break;
}
int update_parameter = 1;
le_connection_parameter_range_t existing_range;
gap_get_connection_parameter_range(existing_range);
uint16_t le_conn_interval_min = little_endian_read_16(packet,12);
uint16_t le_conn_interval_max = little_endian_read_16(packet,14);
uint16_t le_conn_latency = little_endian_read_16(packet,16);
uint16_t le_supervision_timeout = little_endian_read_16(packet,18);
if (le_conn_interval_min < existing_range.le_conn_interval_min) update_parameter = 0;
if (le_conn_interval_max > existing_range.le_conn_interval_max) update_parameter = 0;
if (le_conn_latency < existing_range.le_conn_latency_min) update_parameter = 0;
if (le_conn_latency > existing_range.le_conn_latency_max) update_parameter = 0;
if (le_supervision_timeout < existing_range.le_supervision_timeout_min) update_parameter = 0;
if (le_supervision_timeout > existing_range.le_supervision_timeout_max) update_parameter = 0;
if (update_parameter){
connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_SEND_RESPONSE;
connection->le_conn_interval_min = le_conn_interval_min;
connection->le_conn_interval_max = le_conn_interval_max;
connection->le_conn_latency = le_conn_latency;
connection->le_supervision_timeout = le_supervision_timeout;
} else {
connection->le_con_parameter_update_state = CON_PARAMETER_UPDATE_DENY;
}
connection->le_con_param_update_identifier = packet[COMPLETE_L2CAP_HEADER + 1];
}
hci_dump_packet( HCI_EVENT_PACKET, 0, event, sizeof(event));
if (!l2cap_event_packet_handler) break;
(*l2cap_event_packet_handler)( HCI_EVENT_PACKET, 0, event, sizeof(event));
break;
}
default: {
uint8_t sig_id = packet[COMPLETE_L2CAP_HEADER + 1];
l2cap_register_signaling_response(handle, COMMAND_REJECT_LE, sig_id, L2CAP_REJ_CMD_UNKNOWN);
break;
}
}
break;
}
default: {
// Find channel for this channel_id and connection handle
l2cap_channel_t * channel = l2cap_get_channel_for_local_cid(channel_id);
if (channel) {
l2cap_dispatch_to_channel(channel, L2CAP_DATA_PACKET, &packet[COMPLETE_L2CAP_HEADER], size-COMPLETE_L2CAP_HEADER);
}
break;
}
}
l2cap_run();
}
// finalize closed channel - l2cap_handle_disconnect_request & DISCONNECTION_RESPONSE
void l2cap_finialize_channel_close(l2cap_channel_t *channel){
channel->state = L2CAP_STATE_CLOSED;
l2cap_emit_channel_closed(channel);
// discard channel
l2cap_stop_rtx(channel);
btstack_linked_list_remove(&l2cap_channels, (btstack_linked_item_t *) channel);
btstack_memory_l2cap_channel_free(channel);
}
static l2cap_service_t * l2cap_get_service_internal(btstack_linked_list_t * services, uint16_t psm){
btstack_linked_list_iterator_t it;
btstack_linked_list_iterator_init(&it, services);
while (btstack_linked_list_iterator_has_next(&it)){
l2cap_service_t * service = (l2cap_service_t *) btstack_linked_list_iterator_next(&it);
if ( service->psm == psm){
return service;
};
}
return NULL;
}
static inline l2cap_service_t * l2cap_get_service(uint16_t psm){
return l2cap_get_service_internal(&l2cap_services, psm);
}
uint8_t l2cap_register_service(btstack_packet_handler_t service_packet_handler, uint16_t psm, uint16_t mtu, gap_security_level_t security_level){
log_info("L2CAP_REGISTER_SERVICE psm 0x%x mtu %u", psm, mtu);
// check for alread registered psm
// TODO: emit error event
l2cap_service_t *service = l2cap_get_service(psm);
if (service) {
log_error("l2cap_register_service: PSM %u already registered", psm);
return L2CAP_SERVICE_ALREADY_REGISTERED;
}
// alloc structure
// TODO: emit error event
service = btstack_memory_l2cap_service_get();
if (!service) {
log_error("l2cap_register_service: no memory for l2cap_service_t");
return BTSTACK_MEMORY_ALLOC_FAILED;
}
// fill in
service->psm = psm;
service->mtu = mtu;
service->packet_handler = service_packet_handler;
service->required_security_level = security_level;
// add to services list
btstack_linked_list_add(&l2cap_services, (btstack_linked_item_t *) service);
// enable page scan
hci_connectable_control(1);
return 0;
}
void l2cap_unregister_service(uint16_t psm){
log_info("L2CAP_UNREGISTER_SERVICE psm 0x%x", psm);
l2cap_service_t *service = l2cap_get_service(psm);
if (!service) return;
btstack_linked_list_remove(&l2cap_services, (btstack_linked_item_t *) service);
btstack_memory_l2cap_service_free(service);
// disable page scan when no services registered
if (!btstack_linked_list_empty(&l2cap_services)) return;
hci_connectable_control(0);
}
// Bluetooth 4.0 - allows to register handler for Attribute Protocol and Security Manager Protocol
void l2cap_register_fixed_channel(btstack_packet_handler_t the_packet_handler, uint16_t channel_id) {
int index = l2cap_fixed_channel_table_index_for_channel_id(channel_id);
if (index < 0) return;
fixed_channels[index].callback = the_packet_handler;
}
#ifdef ENABLE_BLE
#if 0
static inline l2cap_service_t * l2cap_le_get_service(uint16_t psm){
return l2cap_get_service_internal(&l2cap_le_services, psm);
}
/**
* @brief Regster L2CAP LE Credit Based Flow Control Mode service
* @param
*/
void l2cap_le_register_service(btstack_packet_handler_t packet_handler, uint16_t psm,
uint16_t mtu, uint16_t mps, uint16_t initial_credits, gap_security_level_t security_level){
log_info("L2CAP_LE_REGISTER_SERVICE psm 0x%x mtu %u connection %p", psm, mtu, connection);
// check for alread registered psm
// TODO: emit error event
l2cap_service_t *service = l2cap_le_get_service(psm);
if (service) {
log_error("l2cap_le_register_service_internal: PSM %u already registered", psm);
l2cap_emit_service_registered(connection, L2CAP_SERVICE_ALREADY_REGISTERED, psm);
return;
}
// alloc structure
// TODO: emit error event
service = btstack_memory_l2cap_service_get();
if (!service) {
log_error("l2cap_register_service_internal: no memory for l2cap_service_t");
l2cap_emit_service_registered(connection, BTSTACK_MEMORY_ALLOC_FAILED, psm);
return;
}
// fill in
service->psm = psm;
service->mtu = mtu;
service->mps = mps;
service->packet_handler = packet_handler;
service->required_security_level = security_level;
// add to services list
btstack_linked_list_add(&l2cap_le_services, (btstack_linked_item_t *) service);
// done
l2cap_emit_service_registered(connection, 0, psm);
}
void l2cap_le_unregister_service(uint16_t psm) {
log_info("L2CAP_LE_UNREGISTER_SERVICE psm 0x%x", psm);
l2cap_service_t *service = l2cap_le_get_service(psm);
if (!service) return;
btstack_linked_list_remove(&l2cap_le_services, (btstack_linked_item_t *) service);
btstack_memory_l2cap_service_free(service);
}
#endif
#endif