mesh_led_control_example.cpp

/*
 * Copyright (c) 2016 ARM Limited. All rights reserved.
 * SPDX-License-Identifier: Apache-2.0
 * Licensed under the Apache License, Version 2.0 (the License); you may
 * not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include "mbed.h"
#include "nanostack/socket_api.h"
#include "mesh_led_control_example.h"
#include "common_functions.h"
#include "ip6string.h"
#include "mbed-trace/mbed_trace.h"

static void init_socket();
static void handle_socket();
static void receive();
static void my_button_isr();
static void send_message();
static void blink();
static void update_state(uint8_t state);
static void handle_message(char* msg);

#define multicast_addr_str "ff15::810a:64d1"
#define TRACE_GROUP "example"
#define UDP_PORT 1234
#define MESSAGE_WAIT_TIMEOUT (30.0)
#define MASTER_GROUP 0
#define MY_GROUP 1

DigitalOut led_1(MBED_CONF_APP_LED, 1);
InterruptIn my_button(MBED_CONF_APP_BUTTON);
DigitalOut output(MBED_CONF_APP_RELAY_CONTROL, 1);

NetworkInterface * network_if;
UDPSocket* my_socket;
// queue for sending messages from button press.
EventQueue queue;
// for LED blinking
Ticker ticker;
// Handle for delayed message send
int queue_handle = 0;

uint8_t multi_cast_addr[16] = {0};
uint8_t receive_buffer[20];
// how many hops the multicast message can go
static const int16_t multicast_hops = 10;
bool button_status = 0;

void start_mesh_led_control_example(NetworkInterface * interface){
    tr_debug("start_mesh_led_control_example()");
    MBED_ASSERT(MBED_CONF_APP_LED != NC);
    MBED_ASSERT(MBED_CONF_APP_BUTTON != NC);

    network_if = interface;
    stoip6(multicast_addr_str, strlen(multicast_addr_str), multi_cast_addr);
    init_socket();
}

static void blink() {
    led_1 = !led_1;
}

void start_blinking() {
    ticker.attach(blink, 1.0);
}

void cancel_blinking() {
    ticker.detach();
    led_1=1;
}

static void send_message() {
    tr_debug("send msg %d", button_status);

    char buf[20];
    int length;

    /**
    * Multicast control message is a NUL terminated string of semicolon separated
    * <field identifier>:<value> pairs.
    *
    * Light control message format:
    * t:lights;g:<group_id>;s:<1|0>;\0
    */
    length = snprintf(buf, sizeof(buf), "t:lights;g:%03d;s:%s;", MY_GROUP, (button_status ? "1" : "0")) + 1;
    MBED_ASSERT(length > 0);
    tr_debug("Sending lightcontrol message, %d bytes: %s", length, buf);
    SocketAddress send_sockAddr(multi_cast_addr, NSAPI_IPv6, UDP_PORT);
    my_socket->sendto(send_sockAddr, buf, 20);
    //After message is sent, it is received from the network
}

// As this comes from isr, we cannot use printing or network functions directly from here.
static void my_button_isr() {
    button_status = !button_status;
    queue.call(send_message);
}

static void update_state(uint8_t state) {
    if (state == 1) {
       tr_debug("Turning led on\n");
       led_1 = 0;
       button_status=1;
       if (MBED_CONF_APP_RELAY_CONTROL != NC) {
          output = 0;
       } else {
          printf("Pins not configured. Skipping the RELAY control.\n");
       }
    }
    else {
       tr_debug("Turning led off\n");
       led_1 = 1;
       button_status=0;
       if (MBED_CONF_APP_RELAY_CONTROL != NC) {
          output = 1;
       } else {
          printf("Pins not configured. Skipping the RELAY control.\n");
       }
    }
}

static void handle_message(char* msg) {
    // Check if this is lights message
    uint8_t state=button_status;
    uint16_t group=0xffff;

    if (strstr(msg, "t:lights;") == NULL) {
       return;
    }

    if (strstr(msg, "s:1;") != NULL) {
        state = 1;
    }
    else if (strstr(msg, "s:0;") != NULL) {
        state = 0;
    }

    // 0==master, 1==default group
    char *msg_ptr = strstr(msg, "g:");
    if (msg_ptr) {
        char *ptr;
        group = strtol(msg_ptr, &ptr, 10);
    }

    // in this example we only use one group
    if (group==MASTER_GROUP || group==MY_GROUP) {
        update_state(state);
    }
}

static void receive() {
    // Read data from the socket
    SocketAddress source_addr;
    memset(receive_buffer, 0, sizeof(receive_buffer));
    bool something_in_socket=true;
    // read all messages
    while (something_in_socket) {
        int length = my_socket->recvfrom(&source_addr, receive_buffer, sizeof(receive_buffer) - 1);
        if (length > 0) {
            int timeout_value = MESSAGE_WAIT_TIMEOUT;
            tr_debug("Packet from %s\n", source_addr.get_ip_address());
            timeout_value += rand() % 30;
            tr_debug("Advertisiment after %d seconds", timeout_value);
            queue.cancel(queue_handle);
            queue_handle = queue.call_in((timeout_value * 1000), send_message);
            // Handle command - "on", "off"
            handle_message((char*)receive_buffer);
        }
        else if (length!=NSAPI_ERROR_WOULD_BLOCK) {
            tr_error("Error happened when receiving %d\n", length);
            something_in_socket=false;
        }
        else {
            // there was nothing to read.
            something_in_socket=false;
        }
    }
}

static void handle_socket() {
    // call-back might come from ISR
    queue.call(receive);
}

static void init_socket()
{
    my_socket = new UDPSocket();
    my_socket->open(network_if);
    my_socket->set_blocking(false);
    my_socket->bind(UDP_PORT);
    my_socket->setsockopt(SOCKET_IPPROTO_IPV6, SOCKET_IPV6_MULTICAST_HOPS, &multicast_hops, sizeof(multicast_hops));

    ns_ipv6_mreq_t mreq;
    memcpy(mreq.ipv6mr_multiaddr, multi_cast_addr, 16);
    mreq.ipv6mr_interface = 0;

    my_socket->setsockopt(SOCKET_IPPROTO_IPV6, SOCKET_IPV6_JOIN_GROUP, &mreq, sizeof mreq);

    if (MBED_CONF_APP_BUTTON != NC) {
        my_button.fall(&my_button_isr);
        my_button.mode(MBED_CONF_APP_BUTTON_MODE);
    }
    //let's register the call-back function.
    //If something happens in socket (packets in or out), the call-back is called.
    my_socket->sigio(callback(handle_socket));
    // dispatch forever
    queue.dispatch();
}