mirror of
https://github.com/lwip-tcpip/lwip.git
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127 lines
4.6 KiB
C
127 lines
4.6 KiB
C
/**
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* @defgroup lwip lwIP
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*
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* @defgroup infrastructure Infrastructure
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*
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* @defgroup callbackstyle_api Callback-style APIs
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* Non thread-safe APIs, callback style for maximum performance and minimum
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* memory footprint.
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*
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* @defgroup sequential_api Sequential-style APIs
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* Sequential-style APIs, blocking functions. More overhead, but can be called
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* from any thread except TCPIP thread.
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*
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* @defgroup addons Addons
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*
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* @defgroup apps Applications
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*/
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/**
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* @mainpage Overview
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* @verbinclude "README"
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*/
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/**
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* @page upgrading Upgrading
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* @verbinclude "UPGRADING"
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*/
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/**
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* @page contrib How to contribute to lwIP
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* @verbinclude "contrib.txt"
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*/
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/**
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* @page pitfalls Common pitfalls
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*
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* Multiple Execution Contexts in lwIP code
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* ========================================
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*
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* The most common source of lwIP problems is to have multiple execution contexts
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* inside the lwIP code.
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*
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* lwIP can be used in two basic modes: @ref lwip_nosys (no OS/RTOS
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* running on target system) or @ref lwip_os (there is an OS running
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* on the target system).
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*
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* Mainloop Mode
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* -------------
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* In mainloop mode, only @ref callbackstyle_api can be used.
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* The user has two possibilities to ensure there is only one
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* exection context at a time in lwIP:
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*
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* 1) Deliver RX ethernet packets directly in interrupt context to lwIP
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* by calling netif->input directly in interrupt. This implies all lwIP
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* callback functions are called in IRQ context, which may cause further
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* problems in application code: IRQ is blocked for a long time, multiple
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* execution contexts in application code etc. When the application wants
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* to call lwIP, it only needs to disable interrupts during the call.
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* If timers are involved, even more locking code is needed to lock out
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* timer IRQ and ethernet IRQ from each other, assuming these may be nested.
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*
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* 2) Run lwIP in a mainloop. There is example code here: @ref lwip_nosys.
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* lwIP is _ONLY_ called from mainloop callstacks here. The ethernet IRQ
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* has to put received telegrams into a queue which is polled in the
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* mainloop. Ensure lwIP is _NEVER_ called from an interrupt, e.g.
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* some SPI IRQ wants to forward data to udp_send() or tcp_write()!
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*
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* OS Mode
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* -------
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* In OS mode, @ref callbackstyle_api AND @ref sequential_api can be used.
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* @ref sequential_api are designed to be called from threads other than
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* the TCPIP thread, so there is nothing to consider here.
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* But @ref callbackstyle_api functions must _ONLY_ be called from
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* TCPIP thread. It is a common error to call these from other threads
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* or from IRQ contexts. Ethernet RX needs to deliver incoming packets
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* in the correct way by sending a message to TCPIP thread, this is
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* implemented in tcpip_input().
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* Again, ensure lwIP is _NEVER_ called from an interrupt, e.g.
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* some SPI IRQ wants to forward data to udp_send() or tcp_write()!
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*
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* 1) tcpip_callback() can be used get called back from TCPIP thread,
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* it is safe to call any @ref callbackstyle_api from there.
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*
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* 2) Use @ref LWIP_TCPIP_CORE_LOCKING. All @ref callbackstyle_api
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* functions can be called when lwIP core lock is aquired, see
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* @ref LOCK_TCPIP_CORE() and @ref UNLOCK_TCPIP_CORE().
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* These macros cannot be used in an interrupt context!
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* Note the OS must correctly handle priority inversion for this.
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*/
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/**
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* @page bugs Reporting bugs
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* Please report bugs in the lwIP bug tracker at savannah.\n
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* BEFORE submitting, please check if the bug has already been reported!\n
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* https://savannah.nongnu.org/bugs/?group=lwip
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*/
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/**
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* @defgroup lwip_nosys Mainloop mode ("NO_SYS")
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* @ingroup lwip
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* Use this mode if you do not run an OS on your system. \#define NO_SYS to 1.
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* Feed incoming packets to netif->input(pbuf, netif) function from mainloop,
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* *not* *from* *interrupt* *context*. You can allocate a @ref pbuf in interrupt
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* context and put them into a queue which is processed from mainloop.\n
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* Call sys_check_timeouts() periodically in the mainloop.\n
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* Porting: implement all functions in @ref sys_time and @ref sys_prot.\n
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* You can only use @ref callbackstyle_api in this mode.\n
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* Sample code:\n
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* @include NO_SYS_SampleCode.c
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*/
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/**
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* @defgroup lwip_os OS mode (TCPIP thread)
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* @ingroup lwip
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* Use this mode if you run an OS on your system. It is recommended to
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* use an RTOS that correctly handles priority inversion and
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* to use @ref LWIP_TCPIP_CORE_LOCKING.\n
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* Porting: implement all functions in @ref sys_layer.\n
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* You can use @ref callbackstyle_api together with @ref tcpip_callback,
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* and all @ref sequential_api.
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*/
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/**
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* @page raw_api lwIP API
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* @verbinclude "rawapi.txt"
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*/
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