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Network Buffer
[Network device drivers.]

Network buffer support. More...

Data Structures
struct	_NBDATA
	Data part of a network buffer structure. More...
struct	_NBDATA
	Data part of a network buffer structure. More...
struct	_NETBUF
	Network buffer structure. More...
struct	_NETBUF
	Network buffer structure. More...
Defines
#define	NBAF_DATALINK
	Datalink buffer allocated flag.
#define	NBAF_NETWORK
	Network buffer allocated flag.
#define	NBAF_TRANSPORT
	Transport buffer allocated flag.
#define	NBAF_APPLICATION
	Application buffer allocated flag.
#define	NBAF_ALL
	Masks allocated buffer flags flag.
Typedefs
typedef _NETBUF	NETBUF
	Network buffer type.
typedef _NBDATA	NBDATA
	Network buffer data type.
Functions
__BEGIN_DECLS NETBUF *	NutNetBufAlloc (NETBUF *nb, u_char type, u_short size)
	Allocate or re-allocate a network buffer part.
NETBUF *	NutNetBufClone (NETBUF *nb)
	Create a copy of an existing network buffer structure.
int	NutNetBufFree (NETBUF *nb)
	Release a network buffer structure.

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Detailed Description

Network buffer support.

The network buffer handling is designed to make life easy when it comes to handling ISO-layered communications. By this we're thinking about communications structures that are hierarchically organized.

The idea is that network buffer structures are allocated every time a new packet is either received or ready for sending. The various fields of the network buffer are then handled by matching layers within the appropriate protocol stack.

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Typedef Documentation

typedef struct _NBDATA NBDATA

Network buffer data type.

typedef struct _NETBUF NETBUF

Network buffer type.

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Function Documentation

__BEGIN_DECLS NETBUF* NutNetBufAlloc (  NETBUF *    nb, u_char    type, u_short    size )

Allocate or re-allocate a network buffer part. Parameters: nb  Points to an existing network buffer structure or NULL, if a new structure should be created. An existing buffer must not be used any further if this function returns a null pointer. type  Part of the buffer to be allocated. This can be any of the following: NBAF_DATALINK NBAF_NETWORK NBAF_TRANSPORT NBAF_APPLICATION size  Size of the part to be allocated. Returns: Pointer to the allocated network buffer structure. A null pointer is returned if not enough memory is available and the whole structure is released.

NETBUF* NutNetBufClone (  NETBUF *    nb )

Create a copy of an existing network buffer structure. Parameters: nb  Points to an existing network buffer structure, previously allocated by NutNetBufAlloc(). Returns: Pointer to a newly allocated copy.

int NutNetBufFree (  NETBUF *    nb )

Release a network buffer structure. Returns all memory previously allocated by a network buffer to the available heap space. Parameters: nb  Points to an existing network buffer structure, previously allocated by NutNetBufAlloc(). Returns: 0 if successfull or -1 if the structure contains previously released memory space.

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