Receiving new messages for delivery

The first thing of interest that will occur after each node has rebooted is that one node's Application Layer will generate and announce a new message for delivery.

We handle the EV_APPLICATIONREADY event with our application_ready() function:

EVENT_HANDLER(application_ready)
{
    CnetAddr destaddr;

    lastlength  = sizeof(MSG);
    CHECK(CNET_read_application(&destaddr, &lastmsg, &lastlength));
    CNET_disable_application(ALLNODES);

    printf("down from application, seq=%d\n",nextdatatosend);

    transmit_frame(&lastmsg, DL_DATA, lastlength, nextdatatosend);

    nextdatatosend = 1 - nextdatatosend;
}

• Assignment statements such as  sequence = 1 - sequence;    are used to quickly toggle between the values 0 and 1.