Network buffers

Functions
struct netbuf *	netbuf_new (void)
void	netbuf_delete (struct netbuf *buf)
void *	netbuf_alloc (struct netbuf *buf, u16_t size)
void	netbuf_free (struct netbuf *buf)
err_t	netbuf_ref (struct netbuf *buf, const void *dataptr, u16_t size)
void	netbuf_chain (struct netbuf *head, struct netbuf *tail)
err_t	netbuf_data (struct netbuf *buf, void **dataptr, u16_t *len)
s8_t	netbuf_next (struct netbuf *buf)
void	netbuf_first (struct netbuf *buf)

Detailed Description

Network buffer descriptor for Netconn API. Based on Packet buffers (PBUF) internally to avoid copying data around.
Buffers must not be shared across multiple threads, all functions except netbuf_new() and netbuf_delete() are not thread-safe.

Function Documentation

netbuf_alloc()

void * netbuf_alloc	(	struct netbuf *	buf,
		u16_t	size )

Allocate memory for a packet buffer for a given netbuf.

Parameters

buf	the netbuf for which to allocate a packet buffer
size	the size of the packet buffer to allocate

Returns

pointer to the allocated memory NULL if no memory could be allocated

netbuf_chain()

void netbuf_chain	(	struct netbuf *	head,
		struct netbuf *	tail )

Chain one netbuf to another (

See also

pbuf_chain)

Parameters

head	the first netbuf
tail	netbuf to chain after head, freed by this function, may not be reference after returning

netbuf_data()

err_t netbuf_data	(	struct netbuf *	buf,
		void **	dataptr,
		u16_t *	len )

Get the data pointer and length of the data inside a netbuf.

Parameters

buf	netbuf to get the data from
dataptr	pointer to a void pointer where to store the data pointer
len	pointer to an u16_t where the length of the data is stored

Returns

ERR_OK if the information was retrieved, ERR_BUF on error.

netbuf_delete()

void netbuf_delete

(

struct netbuf *

buf

)

Deallocate a netbuf allocated by netbuf_new().

Parameters

buf	pointer to a netbuf allocated by netbuf_new()

netbuf_first()

void netbuf_first

(

struct netbuf *

buf

)

Move the current data pointer of a packet buffer contained in a netbuf to the beginning of the packet. The packet buffer itself is not modified.

Parameters

buf	the netbuf to modify

netbuf_free()

void netbuf_free

(

struct netbuf *

buf

)

Free the packet buffer included in a netbuf

Parameters

buf	pointer to the netbuf which contains the packet buffer to free

netbuf_new()

struct netbuf * netbuf_new

(

void

)

Create (allocate) and initialize a new netbuf. The netbuf doesn't yet contain a packet buffer!

Returns

a pointer to a new netbuf NULL on lack of memory

netbuf_next()

s8_t netbuf_next

(

struct netbuf *

buf

)

Move the current data pointer of a packet buffer contained in a netbuf to the next part. The packet buffer itself is not modified.

Parameters

buf	the netbuf to modify

Returns

-1 if there is no next part 1 if moved to the next part but now there is no next part 0 if moved to the next part and there are still more parts

netbuf_ref()

err_t netbuf_ref	(	struct netbuf *	buf,
		const void *	dataptr,
		u16_t	size )

Let a netbuf reference existing (non-volatile) data.

Parameters

buf	netbuf which should reference the data
dataptr	pointer to the data to reference
size	size of the data

Returns

ERR_OK if data is referenced ERR_MEM if data couldn't be referenced due to lack of memory