Introduction to Contiki hacking

1
Introduction to Contiki hacking

• Adam Dunkels
• Swedish Institute of Computer Science
• 2 December 2004

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Contiki, kernel, programs

• Kernel
• Contains the main loop of the system
• Calls programs when events occur
• Calls programs when no events occur (polling)
• Programs are loaded on top of kernel (core)
• All communication is made through µIP

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Contiki system control flow
4
A Contiki program consists of ...

• Init function, called by program loader
• LOADER_INIT_FUNC(function_name, arg)
• Eventhandler, called by kernel
• EK_EVENTHANDLER(eventhandler, ev, data)
• Pollhandler, called repetedly by kernel
• EK_POLLHANDLER(pollhandler)

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The hard life of a Contiki program
Kernel
LOADER_INIT_FUNC()
EK_EVENTHANDLER()
EK_POLLHANDLER()
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Example beeper
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Example beeper
/ Declaration of pollhandler function
/ EK_POLLHANDLER(pollhandler)
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Example beeper
/ Declaration of eventhandler function
/ EK_EVENTHANDLER(eventhandler, ev, data)
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Example beeper
/ Declaration of process / EK_PROCESS(p,
Beeper, EK_PRIO_NORMAL,
eventhandler, pollhandler, NULL)
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Example beeper
/ Implementation of init function.
/ LOADER_INIT_FUNC(init, arg)
arg_free(arg) timer_set(timer,
CLOCK_SECOND) ek_start(p)
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Example beeper
/ Implementation of eventhandler.
/ EK_EVENTHANDLER(eventhandler,
ev, data) if(ev EK_EVENT_REQUEST_EXIT)
ek_exit() LOADER_UNLOAD()
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Example beeper
/ Implementation of pollhandler.
/ EK_POLLHANDLER(pollhandler)
if(timer_expired(timer)) beep()
timer_reset(timer)
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Team building network ping pong

• A virtual ball, hopping between sensors
• Red LED shows where ball is
• Shake sensor to alter direction of the ball
• sensors_vib()
• Perhaps use PIR detector instead?
• Single line, lattice?

14
More information!

• Handouts!
• ssh user_at_10.0.0.1
• user contiki1,2,3, password cna
• cd contiki-esb-1.2-cna0/contiki-esb/build-app
• gmake blink.cprg
• ./send blink.cprg 172.16.1.2