ext arguments

Functions
u8_t	tcp_ext_arg_alloc_id (void)
void	tcp_ext_arg_set_callbacks (struct tcp_pcb *pcb, uint8_t id, const struct tcp_ext_arg_callbacks *const callbacks)
void	tcp_ext_arg_set (struct tcp_pcb *pcb, uint8_t id, void *arg)
void *	tcp_ext_arg_get (const struct tcp_pcb *pcb, uint8_t id)

Detailed Description

Additional data storage per tcp pcb

See also

TCP

When LWIP_TCP_PCB_NUM_EXT_ARGS is > 0, every tcp pcb (including listen pcb) includes a number of additional argument entries in an array.

To support memory management, in addition to a 'void *', callbacks can be provided to manage transition from listening pcbs to connections and to deallocate memory when a pcb is deallocated (see struct tcp_ext_arg_callbacks).

After allocating this index, use tcp_ext_arg_set and tcp_ext_arg_get to store and load arguments from this index for a given pcb.

Function Documentation

tcp_ext_arg_alloc_id()

u8_t tcp_ext_arg_alloc_id

(

void

)

Allocate an index to store data in ext_args member of struct tcp_pcb. Returned value is an index in mentioned array. The index is global over all pcbs!

When LWIP_TCP_PCB_NUM_EXT_ARGS is > 0, every tcp pcb (including listen pcb) includes a number of additional argument entries in an array.

To support memory management, in addition to a 'void *', callbacks can be provided to manage transition from listening pcbs to connections and to deallocate memory when a pcb is deallocated (see struct tcp_ext_arg_callbacks).

After allocating this index, use tcp_ext_arg_set and tcp_ext_arg_get to store and load arguments from this index for a given pcb.

Returns

a unique index into struct tcp_pcb.ext_args

tcp_ext_arg_get()

void* tcp_ext_arg_get	(	const struct tcp_pcb *	pcb,
		uint8_t	id
	)

Set data for a given index of ext_args on the specified pcb.

Parameters

pcb	tcp_pcb for which to set the data
id	ext_args index to set (allocated via tcp_ext_arg_alloc_id)

Returns

data pointer at the given index

tcp_ext_arg_set()

void tcp_ext_arg_set	(	struct tcp_pcb *	pcb,
		uint8_t	id,
		void *	arg
	)

Set data for a given index of ext_args on the specified pcb.

Parameters

pcb	tcp_pcb for which to set the data
id	ext_args index to set (allocated via tcp_ext_arg_alloc_id)
arg	data pointer to set

tcp_ext_arg_set_callbacks()

void tcp_ext_arg_set_callbacks	(	struct tcp_pcb *	pcb,
		uint8_t	id,
		const struct tcp_ext_arg_callbacks *const	callbacks
	)

Set callbacks for a given index of ext_args on the specified pcb.

Parameters

pcb	tcp_pcb for which to set the callback
id	ext_args index to set (allocated via tcp_ext_arg_alloc_id)
callbacks	callback table (const since it is referenced, not copied!)