RTT_PACKAGE_BTSTACK/example/hid_host_demo.c

/*
 * Copyright (C) 2017 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
 *
 */

#define BTSTACK_FILE__ "hid_host_demo.c"

/*
 * hid_host_demo.c
 */

/* EXAMPLE_START(hid_host_demo): HID Host Demo
 *
 * @text This example implements an HID Host. For now, it connnects to a fixed device, queries the HID SDP
 * record and opens the HID Control + Interrupt channels
 */

#include <inttypes.h>
#include <stdio.h>

#include "btstack_config.h"
#include "btstack.h"

#define MAX_ATTRIBUTE_VALUE_SIZE 300

// SDP
static uint8_t            hid_descriptor[MAX_ATTRIBUTE_VALUE_SIZE];
static uint16_t           hid_descriptor_len;

static uint16_t           hid_control_psm;
static uint16_t           hid_interrupt_psm;

static uint8_t            attribute_value[MAX_ATTRIBUTE_VALUE_SIZE];
static const unsigned int attribute_value_buffer_size = MAX_ATTRIBUTE_VALUE_SIZE;

// L2CAP
static uint16_t           l2cap_hid_control_cid;
static uint16_t           l2cap_hid_interrupt_cid;

// MBP 2016
static const char * remote_addr_string = "F4-0F-24-3B-1B-E1";
// iMpulse static const char * remote_addr_string = "64:6E:6C:C1:AA:B5";

static bd_addr_t remote_addr;

static btstack_packet_callback_registration_t hci_event_callback_registration;

// Simplified US Keyboard with Shift modifier

#define CHAR_ILLEGAL     0xff
#define CHAR_RETURN     '\n'
#define CHAR_ESCAPE      27
#define CHAR_TAB         '\t'
#define CHAR_BACKSPACE   0x7f

/**
 * English (US)
 */
static const uint8_t keytable_us_none [] = {
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,             /*   0-3 */
    'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',                   /*  4-13 */
    'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',                   /* 14-23 */
    'u', 'v', 'w', 'x', 'y', 'z',                                       /* 24-29 */
    '1', '2', '3', '4', '5', '6', '7', '8', '9', '0',                   /* 30-39 */
    CHAR_RETURN, CHAR_ESCAPE, CHAR_BACKSPACE, CHAR_TAB, ' ',            /* 40-44 */
    '-', '=', '[', ']', '\\', CHAR_ILLEGAL, ';', '\'', 0x60, ',',       /* 45-54 */
    '.', '/', CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,   /* 55-60 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,             /* 61-64 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,             /* 65-68 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,             /* 69-72 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,             /* 73-76 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,             /* 77-80 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,             /* 81-84 */
    '*', '-', '+', '\n', '1', '2', '3', '4', '5',                       /* 85-97 */
    '6', '7', '8', '9', '0', '.', 0xa7,                                 /* 97-100 */
}; 

static const uint8_t keytable_us_shift[] = {
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,             /*  0-3  */
    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',                   /*  4-13 */
    'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',                   /* 14-23 */
    'U', 'V', 'W', 'X', 'Y', 'Z',                                       /* 24-29 */
    '!', '@', '#', '$', '%', '^', '&', '*', '(', ')',                   /* 30-39 */
    CHAR_RETURN, CHAR_ESCAPE, CHAR_BACKSPACE, CHAR_TAB, ' ',            /* 40-44 */
    '_', '+', '{', '}', '|', CHAR_ILLEGAL, ':', '"', 0x7E, '<',         /* 45-54 */
    '>', '?', CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,   /* 55-60 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,             /* 61-64 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,             /* 65-68 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,             /* 69-72 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,             /* 73-76 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,             /* 77-80 */
    CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL, CHAR_ILLEGAL,             /* 81-84 */
    '*', '-', '+', '\n', '1', '2', '3', '4', '5',                       /* 85-97 */
    '6', '7', '8', '9', '0', '.', 0xb1,                                 /* 97-100 */
}; 


/* @section Main application configuration
 *
 * @text In the application configuration, L2CAP is initialized 
 */

/* LISTING_START(PanuSetup): Panu setup */
static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
static void handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);

static void hid_host_setup(void){

    // Initialize L2CAP 
    l2cap_init();

    // register L2CAP Services for reconnections
    l2cap_register_service(packet_handler, PSM_HID_INTERRUPT, 0xffff, gap_get_security_level());
    l2cap_register_service(packet_handler, PSM_HID_CONTROL, 0xffff, gap_get_security_level());

    // Allow sniff mode requests by HID device
    gap_set_default_link_policy_settings(LM_LINK_POLICY_ENABLE_SNIFF_MODE);

    // register for HCI events
    hci_event_callback_registration.callback = &packet_handler;
    hci_add_event_handler(&hci_event_callback_registration);

    // Allow sniff mode requests by HID device
    gap_set_default_link_policy_settings(LM_LINK_POLICY_ENABLE_SNIFF_MODE);

    // Disable stdout buffering
    setbuf(stdout, NULL);
}
/* LISTING_END */

/* @section SDP parser callback 
 * 
 * @text The SDP parsers retrieves the BNEP PAN UUID as explained in  
 * Section [on SDP BNEP Query example](#sec:sdpbnepqueryExample}.
 */

static void handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size) {

    UNUSED(packet_type);
    UNUSED(channel);
    UNUSED(size);

    des_iterator_t attribute_list_it;
    des_iterator_t additional_des_it;
    des_iterator_t prot_it;
    uint8_t       *des_element;
    uint8_t       *element;
    uint32_t       uuid;
    uint8_t        status;

    switch (hci_event_packet_get_type(packet)){
        case SDP_EVENT_QUERY_ATTRIBUTE_VALUE:
            if (sdp_event_query_attribute_byte_get_attribute_length(packet) <= attribute_value_buffer_size) {
                attribute_value[sdp_event_query_attribute_byte_get_data_offset(packet)] = sdp_event_query_attribute_byte_get_data(packet);
                if ((uint16_t)(sdp_event_query_attribute_byte_get_data_offset(packet)+1) == sdp_event_query_attribute_byte_get_attribute_length(packet)) {
                    switch(sdp_event_query_attribute_byte_get_attribute_id(packet)) {
                        case BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST:
                            for (des_iterator_init(&attribute_list_it, attribute_value); des_iterator_has_more(&attribute_list_it); des_iterator_next(&attribute_list_it)) {                                    
                                if (des_iterator_get_type(&attribute_list_it) != DE_DES) continue;
                                des_element = des_iterator_get_element(&attribute_list_it);
                                des_iterator_init(&prot_it, des_element);
                                element = des_iterator_get_element(&prot_it);
                                if (!element) continue;
                                if (de_get_element_type(element) != DE_UUID) continue;
                                uuid = de_get_uuid32(element);
                                des_iterator_next(&prot_it);
                                switch (uuid){
                                    case BLUETOOTH_PROTOCOL_L2CAP:
                                        if (!des_iterator_has_more(&prot_it)) continue;
                                        de_element_get_uint16(des_iterator_get_element(&prot_it), &hid_control_psm);
                                        printf("HID Control PSM: 0x%04x\n", (int) hid_control_psm);
                                        break;
                                    default:
                                        break;
                                }
                            }
                            break;
                        case BLUETOOTH_ATTRIBUTE_ADDITIONAL_PROTOCOL_DESCRIPTOR_LISTS:
                            for (des_iterator_init(&attribute_list_it, attribute_value); des_iterator_has_more(&attribute_list_it); des_iterator_next(&attribute_list_it)) {                                    
                                if (des_iterator_get_type(&attribute_list_it) != DE_DES) continue;
                                des_element = des_iterator_get_element(&attribute_list_it);
                                for (des_iterator_init(&additional_des_it, des_element); des_iterator_has_more(&additional_des_it); des_iterator_next(&additional_des_it)) {                                    
                                    if (des_iterator_get_type(&additional_des_it) != DE_DES) continue;
                                    des_element = des_iterator_get_element(&additional_des_it);
                                    des_iterator_init(&prot_it, des_element);
                                    element = des_iterator_get_element(&prot_it);
                                    if (!element) continue;
                                    if (de_get_element_type(element) != DE_UUID) continue;
                                    uuid = de_get_uuid32(element);
                                    des_iterator_next(&prot_it);
                                    switch (uuid){
                                        case BLUETOOTH_PROTOCOL_L2CAP:
                                            if (!des_iterator_has_more(&prot_it)) continue;
                                            de_element_get_uint16(des_iterator_get_element(&prot_it), &hid_interrupt_psm);
                                            printf("HID Interrupt PSM: 0x%04x\n", (int) hid_interrupt_psm);
                                            break;
                                        default:
                                            break;
                                    }
                                }
                            }
                            break;
                        case BLUETOOTH_ATTRIBUTE_HID_DESCRIPTOR_LIST:
                            for (des_iterator_init(&attribute_list_it, attribute_value); des_iterator_has_more(&attribute_list_it); des_iterator_next(&attribute_list_it)) {
                                if (des_iterator_get_type(&attribute_list_it) != DE_DES) continue;
                                des_element = des_iterator_get_element(&attribute_list_it);
                                for (des_iterator_init(&additional_des_it, des_element); des_iterator_has_more(&additional_des_it); des_iterator_next(&additional_des_it)) {                                    
                                    if (des_iterator_get_type(&additional_des_it) != DE_STRING) continue;
                                    element = des_iterator_get_element(&additional_des_it);
                                    const uint8_t * descriptor = de_get_string(element);
                                    hid_descriptor_len = de_get_data_size(element);
                                    memcpy(hid_descriptor, descriptor, hid_descriptor_len);
                                    printf("HID Descriptor:\n");
                                    printf_hexdump(hid_descriptor, hid_descriptor_len);
                                }
                            }                        
                            break;
                        default:
                            break;
                    }
                }
            } else {
                fprintf(stderr, "SDP attribute value buffer size exceeded: available %d, required %d\n", attribute_value_buffer_size, sdp_event_query_attribute_byte_get_attribute_length(packet));
            }
            break;
            
        case SDP_EVENT_QUERY_COMPLETE:
            if (sdp_event_query_complete_get_status(packet) != ERROR_CODE_SUCCESS){
                printf("SDP Query failed\n");
                break;
            }
            if ((l2cap_hid_interrupt_cid != 0) && (l2cap_hid_control_cid != 0)){
                printf("HID device re-connected\n");
                break;
            }
            if (!hid_control_psm) {
                hid_control_psm = BLUETOOTH_PSM_HID_CONTROL;
                printf("HID Control PSM missing, using default 0x%04x\n", hid_control_psm);
            }
            if (!hid_interrupt_psm) {
                hid_interrupt_psm = BLUETOOTH_PSM_HID_INTERRUPT;
                printf("HID Interrupt PSM missing, using default 0x%04x\n", hid_interrupt_psm);
                break;
            }
            printf("Setup HID\n");
            status = l2cap_create_channel(packet_handler, remote_addr, hid_control_psm, 48, &l2cap_hid_control_cid);
            if (status){
                printf("Connecting to HID Control failed: 0x%02x\n", status);
            }
            break;
    }
}

/*
 * @section HID Report Handler
 * 
 * @text Use BTstack's compact HID Parser to process incoming HID Report
 * Iterate over all fields and process fields with usage page = 0x07 / Keyboard
 * Check if SHIFT is down and process first character (don't handle multiple key presses)
 * 
 */
#define NUM_KEYS 6
static uint8_t last_keys[NUM_KEYS];
static void hid_host_handle_interrupt_report(const uint8_t * report, uint16_t report_len){
    // check if HID Input Report
    if (report_len < 1) return;
    if (*report != 0xa1) return; 
    report++;
    report_len--;
    btstack_hid_parser_t parser;
    btstack_hid_parser_init(&parser, hid_descriptor, hid_descriptor_len, HID_REPORT_TYPE_INPUT, report, report_len);
    int shift = 0;
    uint8_t new_keys[NUM_KEYS];
    memset(new_keys, 0, sizeof(new_keys));
    int     new_keys_count = 0;
    while (btstack_hid_parser_has_more(&parser)){
        uint16_t usage_page;
        uint16_t usage;
        int32_t  value;
        btstack_hid_parser_get_field(&parser, &usage_page, &usage, &value);
        if (usage_page != 0x07) continue;   
        switch (usage){
            case 0xe1:
            case 0xe6:
                if (value){
                    shift = 1;
                }
                continue;
            case 0x00:
                continue;
            default:
                break;
        }
        if (usage >= sizeof(keytable_us_none)) continue;

        // store new keys
        new_keys[new_keys_count++] = usage;

        // check if usage was used last time (and ignore in that case)
        int i;
        for (i=0;i<NUM_KEYS;i++){
            if (usage == last_keys[i]){
                usage = 0;
            }
        }
        if (usage == 0) continue;

        uint8_t key;
        if (shift){
            key = keytable_us_shift[usage];
        } else {
            key = keytable_us_none[usage];
        }
        if (key == CHAR_ILLEGAL) continue;
        if (key == CHAR_BACKSPACE){ 
            printf("\b \b");    // go back one char, print space, go back one char again
            continue;
        }
        printf("%c", key);
    }
    memcpy(last_keys, new_keys, NUM_KEYS);
}

/*
 * @section Packet Handler
 * 
 * @text The packet handler responds to various HCI Events.
 */

/* LISTING_START(packetHandler): Packet Handler */
static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size)
{
    /* LISTING_PAUSE */
    uint8_t   event;
    bd_addr_t event_addr;
    uint8_t   status;
    uint16_t  l2cap_cid;

    /* LISTING_RESUME */
    switch (packet_type) {
		case HCI_EVENT_PACKET:
            event = hci_event_packet_get_type(packet);
            switch (event) {            
                /* @text When BTSTACK_EVENT_STATE with state HCI_STATE_WORKING
                 * is received and the example is started in client mode, the remote SDP HID query is started.
                 */
                case BTSTACK_EVENT_STATE:
                    if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){
                        printf("Start SDP HID query for remote HID Device %s.\n", bd_addr_to_str(remote_addr));
                        sdp_client_query_uuid16(&handle_sdp_client_query_result, remote_addr, BLUETOOTH_SERVICE_CLASS_HUMAN_INTERFACE_DEVICE_SERVICE);
                    }
                    break;

                /* LISTING_PAUSE */
                case HCI_EVENT_PIN_CODE_REQUEST:
					// inform about pin code request
                    printf("Pin code request - using '0000'\n");
                    hci_event_pin_code_request_get_bd_addr(packet, event_addr);
                    gap_pin_code_response(event_addr, "0000");
					break;

                case HCI_EVENT_USER_CONFIRMATION_REQUEST:
                    // inform about user confirmation request
                    printf("SSP User Confirmation Request with numeric value '%"PRIu32"'\n", little_endian_read_32(packet, 8));
                    printf("SSP User Confirmation Auto accept\n");
                    break;

                /* LISTING_RESUME */
                case L2CAP_EVENT_INCOMING_CONNECTION:
                    l2cap_cid = l2cap_event_incoming_connection_get_local_cid(packet);
                    switch (l2cap_event_incoming_connection_get_psm(packet)){
                        case PSM_HID_CONTROL:
                        case PSM_HID_INTERRUPT:
                            l2cap_accept_connection(l2cap_cid);
                            break;
                        default:
                            l2cap_decline_connection(l2cap_cid);
                            break;
                    }
                    break;
                case L2CAP_EVENT_CHANNEL_OPENED: 
                    status = packet[2];
                    if (status){
                        printf("L2CAP Connection failed: 0x%02x\n", status);
                        break;
                    }
                    l2cap_cid = l2cap_event_channel_opened_get_local_cid(packet);
                    switch (l2cap_event_channel_opened_get_psm(packet)){
                        case PSM_HID_CONTROL:
                            if (l2cap_event_channel_opened_get_incoming(packet) == 0) {
                                status = l2cap_create_channel(packet_handler, remote_addr, hid_interrupt_psm, 48, &l2cap_hid_interrupt_cid);
                                if (status){
                                    printf("Connecting to HID Interrupt failed: 0x%02x\n", status);
                                    break;
                                }
                            }
                            l2cap_hid_control_cid = l2cap_cid;
                            break;
                        case PSM_HID_INTERRUPT:
                            l2cap_hid_interrupt_cid = l2cap_cid;
                            break;
                        default:
                            break;
                    }

                    if ((l2cap_hid_control_cid != 0) && (l2cap_hid_interrupt_cid != 0)){
                        if (hid_descriptor_len == 0){
                            printf("Start SDP HID query to get HID Descriptor\n");
                            sdp_client_query_uuid16(&handle_sdp_client_query_result, remote_addr, BLUETOOTH_SERVICE_CLASS_HUMAN_INTERFACE_DEVICE_SERVICE);
                        } else {
                            printf("HID Connection established\n");
                        }
                    }
                    break;
                case L2CAP_EVENT_CHANNEL_CLOSED:
                    if ((l2cap_hid_control_cid != 0) && (l2cap_hid_interrupt_cid != 0)){
                        printf("HID Connection closed\n");
                        hid_descriptor_len = 0;
                    }
                    l2cap_cid = l2cap_event_channel_closed_get_local_cid(packet);
                    if (l2cap_cid == l2cap_hid_control_cid){
                        l2cap_hid_control_cid = 0;
                    }
                    if (l2cap_cid == l2cap_hid_interrupt_cid){
                        l2cap_hid_interrupt_cid = 0;
                    }
                default:
                    break;
            }
            break;
        case L2CAP_DATA_PACKET:
            // for now, just dump incoming data
            if (channel == l2cap_hid_interrupt_cid){
                hid_host_handle_interrupt_report(packet,  size);
            } else if (channel == l2cap_hid_control_cid){
                printf("HID Control: ");
                printf_hexdump(packet, size);
            } else {
                break;
            }
        default:
            break;
    }
}
/* LISTING_END */

int btstack_main(int argc, const char * argv[]);
int btstack_main(int argc, const char * argv[]){

    (void)argc;
    (void)argv;

    hid_host_setup();

    // parse human readable Bluetooth address
    sscanf_bd_addr(remote_addr_string, remote_addr);

    // Turn on the device 
    hci_power_control(HCI_POWER_ON);
    return 0;
}

/* EXAMPLE_END */