netbuf.c File Reference

Network buffer management.

#include "lwip/opt.h"
#include "lwip/netbuf.h"
#include "lwip/memp.h"
#include <string.h>

Functions
void *	netbuf_alloc (struct netbuf *buf, u16_t size)
	Allocate memory for a packet buffer for a given netbuf. More...
void	netbuf_chain (struct netbuf *head, struct netbuf *tail)
	Chain one netbuf to another (. More...
err_t	netbuf_data (struct netbuf *buf, void **dataptr, u16_t *len)
	Get the data pointer and length of the data inside a netbuf. More...
void	netbuf_delete (struct netbuf *buf)
	Deallocate a netbuf allocated by netbuf_new(). More...
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. More...
void	netbuf_free (struct netbuf *buf)
	Free the packet buffer included in a netbuf. More...
struct netbuf *	netbuf_new (void)
	Create (allocate) and initialize a new netbuf. More...
s8_t	netbuf_next (struct netbuf *buf)
	Move the current data pointer of a packet buffer contained in a netbuf to the next part. More...
err_t	netbuf_ref (struct netbuf *buf, const void *dataptr, u16_t size)
	Let a netbuf reference existing (non-volatile) data. More...

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

References pbuf::len, LWIP_ASSERT, LWIP_ERROR(), NULL, netbuf::p, pbuf::payload, pbuf_alloc(), pbuf_free(), PBUF_RAM, PBUF_TRANSPORT, and netbuf::ptr.

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

References LWIP_ERROR(), memp_free(), NULL, netbuf::p, pbuf_cat(), and netbuf::ptr.

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 retreived, ERR_BUF on error.

References ERR_ARG, ERR_BUF, ERR_OK, pbuf::len, LWIP_ERROR(), NULL, pbuf::payload, and netbuf::ptr.

Referenced by http_request().

void netbuf_delete

(

struct netbuf *

buf

)

Deallocate a netbuf allocated by netbuf_new().

Parameters

buf	pointer to a netbuf allocated by netbuf_new()

References memp_free(), NULL, netbuf::p, pbuf_free(), and netbuf::ptr.

Referenced by http_request(), netconn_drain(), and recv_udp().

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

References LWIP_ERROR(), NULL, netbuf::p, and netbuf::ptr.

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

References LWIP_ERROR(), NULL, netbuf::p, pbuf_free(), and netbuf::ptr.

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

References netbuf::addr, ip_addr_set_any, memp_malloc(), NULL, netbuf::p, netbuf::port, and netbuf::ptr.

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

References LWIP_ERROR(), pbuf::next, NULL, and netbuf::ptr.

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

References ERR_ARG, ERR_MEM, ERR_OK, pbuf::len, LWIP_ERROR(), NULL, netbuf::p, pbuf::payload, pbuf_alloc(), pbuf_free(), PBUF_REF, PBUF_TRANSPORT, netbuf::ptr, and pbuf::tot_len.