Changed packet drivers from services to plain processes.
Now tcpip_output() is a function pointer that is supposed to be set via the macro tcpip_set_outputfunc(). Packet drivers do so on process startup. Thus if there are several packet drivers in a Contiki system the one started last is the one actually used. This behaviour is especially useful for the 'IP forwarding' "meta" packet driver.
This commit is contained in:
parent
3f4ec3cf44
commit
080ecc5488
6 changed files with 139 additions and 365 deletions
138
doc/example-packet-drv.c
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138
doc/example-packet-drv.c
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@ -0,0 +1,138 @@
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/*
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* This is an example of how to write a network device driver ("packet
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* driver") for Contiki. A packet driver is a regular Contiki process
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* that does two things:
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* # Checks for incoming packets and delivers those to the TCP/IP stack
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* # Provides an output function that transmits packets
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*
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* The output function is registered with the Contiki TCP/IP stack,
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* whereas incoming packets must be checked inside a Contiki process.
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* We use the same process for checking for incoming packets and for
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* registering the output function.
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*/
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/*
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* We include the "contiki-net.h" file to get all the network functions.
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*/
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#include "contiki-net.h"
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/*---------------------------------------------------------------------------*/
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/*
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* We declare the process that we use to register with the TCP/IP stack,
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* and to check for incoming packets.
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*/
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PROCESS(example_packet_driver_process, "Example packet driver process");
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/*---------------------------------------------------------------------------*/
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/*
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* Next, we define the function that transmits packets. This function
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* is called from the TCP/IP stack when a packet is to be transmitted.
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* The packet is located in the uip_buf[] buffer, and the length of the
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* packet is in the uip_len variable.
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*/
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u8_t
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example_packet_driver_output(void)
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{
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let_the_hardware_send_the_packet(uip_buf, uip_len);
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}
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/*---------------------------------------------------------------------------*/
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/*
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* This is the poll handler function in the process below. This poll
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* handler function checks for incoming packets and delivers them to
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* the TCP/IP stack.
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*/
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static void
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pollhandler(void)
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{
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/*
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* We assume that we have some hardware device that notifies us when
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* a new packet has arrived. We also assume that we have a function
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* that pulls out the new packet (here called
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* check_and_copy_packet()) and puts it in the uip_buf[] buffer. The
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* function returns the length of the incoming packet, and we store
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* it in the global uip_len variable. If the packet is longer than
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* zero bytes, we hand it over to the TCP/IP stack.
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*/
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uip_len = check_and_copy_packet();
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/*
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* The function tcpip_input() delivers the packet in the uip_buf[]
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* buffer to the TCP/IP stack.
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*/
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if(uip_len > 0) {
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tcpip_input();
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}
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/*
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* Now we'll make sure that the poll handler is executed repeatedly.
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* We do this by calling process_poll() with this process as its
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* argument.
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*
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* In many cases, the hardware will cause an interrupt to be executed
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* when a new packet arrives. For such hardware devices, the interrupt
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* handler calls process_poll() (which is safe to use in an interrupt
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* context) instead.
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*/
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process_poll(&example_packet_driver_process);
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}
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/*---------------------------------------------------------------------------*/
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/*
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* Here we shutdown the hardware in case the process exits.
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*/
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static void
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exithandler(void)
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{
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shutdown_the_hardware();
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}
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/*---------------------------------------------------------------------------*/
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/*
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* Finally, we define the process that does the work.
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*/
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PROCESS_THREAD(example_packet_driver_process, ev, data)
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{
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/*
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* This process has a poll handler, so we declare it here. Note that
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* the PROCESS_POLLHANDLER() macro must come before the PROCESS_BEGIN()
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* macro.
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*/
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PROCESS_POLLHANDLER(pollhandler());
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/*
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* This process has an exit handler, so we declare it here. Note that
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* the PROCESS_EXITHANDLER() macro must come before the PROCESS_BEGIN()
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* macro.
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*/
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PROCESS_EXITHANDLER(exithandler());
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/*
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* The process begins here.
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*/
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PROCESS_BEGIN();
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/*
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* We start with initializing the hardware.
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*/
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initialize_the_hardware();
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/*
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* Register the driver. This will cause any previously registered driver
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* to be ignored by the TCP/IP stack.
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*/
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tcpip_set_outputfunc(example_packet_driver_output);
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/*
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* Now we'll make sure that the poll handler is executed initially. We do
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* this by calling process_poll() with this process as its argument.
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*/
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process_poll(&example_packet_driver_process);
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/*
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* And we wait for the process to exit.
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*/
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PROCESS_WAIT_EVENT_UNTIL(ev == PROCESS_EVENT_EXIT);
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/*
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* Here ends the process.
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*/
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PROCESS_END();
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}
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/*---------------------------------------------------------------------------*/
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@ -1,148 +0,0 @@
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/*
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* This is an example of how to write a network device driver ("packet
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* service") for Contiki. A packet service is a regular Contiki
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* service that does two things:
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* # Checks for incoming packets and delivers those to the TCP/IP stack
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* # Provides an output function that transmits packets
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*
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* The output function is registered with the Contiki service
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* mechanism, whereas incoming packets must be checked inside a
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* Contiki process. We use the same process for checking for incoming
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* packets and for registering the service.
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*
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* NOTE: This example does not work with the uip-fw module (packet
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* forwarding with multiple interfaces). It only works with a single
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* interface.
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*/
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/*
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* We include the "contiki-net.h" file to get all the network
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* functions.
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*/
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#include "contiki-net.h"
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/*---------------------------------------------------------------------------*/
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/*
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* We declare the process that we use to register the service, and to
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* check for incoming packets.
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*/
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PROCESS(example_packet_service_process, "Example packet service process");
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/*---------------------------------------------------------------------------*/
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/*
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* This is the poll handler function in the process below. This poll
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* handler function checks for incoming packets and delivers them to
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* the TCP/IP stack.
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*/
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static void
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pollhandler(void)
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{
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/*
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* We assume that we have some hardware device that notifies us when
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* a new packet has arrived. We also assume that we have a function
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* that pulls out the new packet (here called
|
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* check_and_copy_packet()) and puts it in the uip_buf[] buffer. The
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* function returns the length of the incoming packet, and we store
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* it in the global uip_len variable. If the packet is longer than
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* zero bytes, we hand it over to the TCP/IP stack.
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*/
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uip_len = check_and_copy_packet();
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/*
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* The function tcpip_input() delivers the packet in the uip_buf[]
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* buffer to the TCP/IP stack.
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*/
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if(uip_len > 0) {
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tcpip_input();
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}
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/*
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* Now we'll make sure that the poll handler is executed
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* repeatedly. We do this by calling process_poll() with this
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* process as its argument.
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*
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* In many cases, the hardware will cause an interrupt to be
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* executed when a new packet arrives. For such hardware devices,
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* the interrupt handler calls process_poll() (which is safe to use
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* in an interrupt context) instead.
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*/
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process_poll(&example_packet_service_process);
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}
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/*---------------------------------------------------------------------------*/
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/*
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* Next, we define the function that transmits packets. This function
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* is called from the TCP/IP stack when a packet is to be
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* transmitted. The packet is located in the uip_buf[] buffer, and the
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* length of the packet is in the uip_len variable.
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*/
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static void
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send_packet(void)
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{
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let_the_hardware_send_the_packet(uip_buf, uip_len);
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}
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/*---------------------------------------------------------------------------*/
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/*
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* Now we declare the service. We call the service
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* example_packet_service because of the name of this file. The
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* service should be an instance of the "packet service" service, so
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* we give packet_service as the second argument. Finally we give our
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* send_packet() function as the last argument, because of how the
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* packet_service interface is defined.
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*
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* We'll register this service with the Contiki system in the process
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* defined below.
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*/
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SERVICE(example_packet_service, packet_service, { send_packet });
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/*---------------------------------------------------------------------------*/
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/*
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* Finally, we define the process that does the work.
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*/
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PROCESS_THREAD(example_packet_service_process, ev, data)
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{
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/*
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* This process has a poll handler, so we declare it here. Note that
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* the PROCESS_POLLHANDLER() macro must come before the
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* PROCESS_BEGIN() macro.
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*/
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PROCESS_POLLHANDLER(pollhandler());
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/*
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* The process begins here.
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*/
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PROCESS_BEGIN();
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/*
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* We start with initializing the hardware.
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*/
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initialize_the_hardware();
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/*
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* Register the service. This will cause any other instances of the
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* same service to be removed.
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*/
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SERVICE_REGISTER(example_packet_service);
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/*
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* Now we'll make sure that the poll handler is executed
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* initially. We do this by calling process_poll() with this
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* process as its argument.
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*/
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process_poll(&example_packet_service_process);
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/*
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* And we wait for either the process to exit, or for the service to
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* be removed (by someone else).
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*/
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PROCESS_WAIT_EVENT_UNTIL(ev == PROCESS_EVENT_EXIT ||
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ev == PROCESS_EVENT_SERVICE_REMOVED);
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/*
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* And we always end with explicitly removing the service.
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*/
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SERVICE_REMOVE(example_packet_service);
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/*
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* Here endeth the process.
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*/
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PROCESS_END();
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}
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/*---------------------------------------------------------------------------*/
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@ -1,115 +0,0 @@
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/*
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* This file is an example of how to implement a service in
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* Contiki. The header file example-service.h defines a service called
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* "example_service", which we implement in this file.
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*
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* This example shows how to define an instance of a service, and how
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* to write the service's controlling process.
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*
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* See the file example-use-service.c for an example of how to call a
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* service.
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*/
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#include <stdio.h>
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#include "example-service.h"
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#include "contiki.h"
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/*---------------------------------------------------------------------------*/
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/*
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* We start by implementing all the functions that the service
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* offers. In this case, there is only a single function (called
|
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* example_function()) and we implement it here. We give it the name
|
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* example() and declare it with the "static" keyword to keep the
|
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* scope local to this file.
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||||
*/
|
||||
static void
|
||||
example(void) {
|
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printf("Example service called\n");
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}
|
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/*---------------------------------------------------------------------------*/
|
||||
/*
|
||||
* This is the instantiation of the service called
|
||||
* "example_service". The service interface is defined in the header
|
||||
* file example-service.h.
|
||||
*
|
||||
* This statement defines the name of this implementation of the
|
||||
* service - example_service_implementation - and defines the
|
||||
* functions that actually implement the functions offered by the
|
||||
* service. In this example, the service consists of a single function
|
||||
* called "example_function()". We implement this function in the
|
||||
* function called "example()" defined above.
|
||||
*
|
||||
*/
|
||||
SERVICE(example_service_implementation, /* The name of this instance
|
||||
of the service - used with
|
||||
SERVICE_REGISTER(). */
|
||||
example_service, /* The name of the serivce
|
||||
that is instantiated. */
|
||||
{ example }); /* The list of functions
|
||||
required by the
|
||||
service. In this case, we
|
||||
only have one function. */
|
||||
|
||||
/*
|
||||
* All services needs a controlling process. The controlling process
|
||||
* registers the service with the system when it starts, and is also
|
||||
* notified if the service is removed or replaced.
|
||||
*
|
||||
* We simply call the process "example_service_process" and gives it a
|
||||
* similar textual name.
|
||||
*/
|
||||
PROCESS(example_service_process, "Example service process");
|
||||
|
||||
/*
|
||||
* For this example, we use a timer to remove the service after a
|
||||
* certain time. We declare the timer here.
|
||||
*/
|
||||
static struct etimer timer;
|
||||
|
||||
/*
|
||||
* Finally, we implement the controlling process.
|
||||
*/
|
||||
PROCESS_THREAD(example_service_process, ev, data)
|
||||
{
|
||||
|
||||
/*
|
||||
* A process thread starts with PROCESS_BEGIN() and ends with
|
||||
* PROCESS_END().
|
||||
*/
|
||||
PROCESS_EXITHANDLER(goto exit);
|
||||
PROCESS_BEGIN();
|
||||
|
||||
/*
|
||||
* We register the service instance with a SERVICE_REGISTER()
|
||||
* statement.
|
||||
*/
|
||||
printf("Registering example service\n");
|
||||
SERVICE_REGISTER(example_service_implementation);
|
||||
|
||||
/*
|
||||
* We set a timer for four seconds and wait for it to expire - or
|
||||
* for the process to receive an event which requests it to exit.
|
||||
*
|
||||
* The only purpose for the timer is to demonstrate how a service is
|
||||
* removed - it is not something that is commonly done.
|
||||
*/
|
||||
etimer_set(&timer, 4 * CLOCK_SECOND);
|
||||
PROCESS_YIELD_UNTIL(ev == PROCESS_EVENT_SERVICE_REMOVED ||
|
||||
etimer_expired(&timer));
|
||||
|
||||
/*
|
||||
* And we remove the service before the process ends. This is a
|
||||
* *very* important step - if the process exits and is unloaded
|
||||
* without first removing its services, the system may crash!
|
||||
*/
|
||||
printf("Removing example service\n");
|
||||
|
||||
/*
|
||||
* And finally the process ends.
|
||||
*/
|
||||
exit:
|
||||
SERVICE_REMOVE(example_service_implementation);
|
||||
PROCESS_END();
|
||||
}
|
||||
/*---------------------------------------------------------------------------*/
|
|
@ -1,33 +0,0 @@
|
|||
/*
|
||||
* This file is an example of how to define a service in Contiki. The
|
||||
* example shows how to define a service interface, and how to give
|
||||
* the service a name.
|
||||
*/
|
||||
#ifndef __EXAMPLE_SERVICE_H__
|
||||
#define __EXAMPLE_SERVICE_H__
|
||||
|
||||
#include "sys/service.h"
|
||||
|
||||
/*
|
||||
* This is how we define the service interface, and give the service a
|
||||
* name. The name of this particular service is "example_service" and
|
||||
* the interface consists of a single function, called
|
||||
* example_function().
|
||||
*/
|
||||
SERVICE_INTERFACE(example_service,
|
||||
{
|
||||
void (* example_function)(void);
|
||||
/* More functions can be added here, line by line. */
|
||||
});
|
||||
|
||||
/*
|
||||
* We must also give the service a textual name. We do this by using a
|
||||
* special #define statment - we define a macro with the same name as
|
||||
* the service, but postfixed with "_name".
|
||||
*
|
||||
* The textual name is used when looking up services. The name must be
|
||||
* unique within the system.
|
||||
*/
|
||||
#define example_service_name "Example service"
|
||||
|
||||
#endif /* __EXAMPLE_SERVICE_H__ */
|
|
@ -1,65 +0,0 @@
|
|||
/*
|
||||
* This file contains an example of how to call a service.
|
||||
*
|
||||
* This program implements a process that calls the service defined in
|
||||
* example-service.h every second.
|
||||
*/
|
||||
|
||||
#include <stdio.h>
|
||||
|
||||
#include "contiki.h"
|
||||
|
||||
/*
|
||||
* We must include the header file for the service.
|
||||
*/
|
||||
#include "example-service.h"
|
||||
|
||||
/*
|
||||
* All Contiki programs must have a process, and we declare it here.
|
||||
*/
|
||||
PROCESS(example_use_service_process, "Use example");
|
||||
|
||||
/*
|
||||
* The program is to call the service once every second, so we use an
|
||||
* event timer in order to run every second.
|
||||
*/
|
||||
static struct etimer timer;
|
||||
|
||||
/*---------------------------------------------------------------------------*/
|
||||
/*
|
||||
* Here we implement the process.
|
||||
*/
|
||||
PROCESS_THREAD(example_use_service_process, ev, data)
|
||||
{
|
||||
/*
|
||||
* A process thread starts with PROCESS_BEGIN() and ends with
|
||||
* PROCESS_END().
|
||||
*/
|
||||
PROCESS_BEGIN();
|
||||
|
||||
/*
|
||||
* We loop for ever, calling the service once every second.
|
||||
*/
|
||||
while(1) {
|
||||
|
||||
/*
|
||||
* We set a timer that wakes us up once every second.
|
||||
*/
|
||||
etimer_set(&timer, CLOCK_SECOND);
|
||||
PROCESS_YIELD_UNTIL(etimer_expired(&timer));
|
||||
|
||||
/*
|
||||
* We call the service. If the service is not registered, the
|
||||
* SERVICE_CALL() statement does nothing. If we need to know if
|
||||
* the service exists, we can use the SERVICE_FIND() function.
|
||||
*/
|
||||
printf("use example: calling example\n");
|
||||
SERVICE_CALL(example_service, example_function());
|
||||
}
|
||||
|
||||
/*
|
||||
* And finally the process ends.
|
||||
*/
|
||||
PROCESS_END();
|
||||
}
|
||||
/*---------------------------------------------------------------------------*/
|
|
@ -1,10 +1,7 @@
|
|||
/** \example example-program.c */
|
||||
/** \example example-service.c */
|
||||
/** \example example-service.h */
|
||||
/** \example example-use-service.c */
|
||||
/** \example example-pollhandler.c */
|
||||
/** \example example-list.c */
|
||||
/** \example example-packet-service.c */
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/** \example example-packet-drv.c */
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/** \example example-psock-server.c */
|
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|
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/** \example test-abc.c */
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Reference in a new issue