pbuf.h File Reference

#include "lwip/opt.h"
#include "lwip/err.h"

Data Structures
struct	pbuf
struct	pbuf_rom
struct	pbuf_custom

Macros
#define	LWIP_SUPPORT_CUSTOM_PBUF   ((IP_FRAG && !LWIP_NETIF_TX_SINGLE_PBUF) || (LWIP_IPV6 && LWIP_IPV6_FRAG))
#define	PBUF_NEEDS_COPY(p)   ((p)->type_internal & PBUF_TYPE_FLAG_DATA_VOLATILE)
#define	PBUF_TYPE_FLAG_STRUCT_DATA_CONTIGUOUS   0x80
#define	PBUF_TYPE_FLAG_DATA_VOLATILE   0x40
#define	PBUF_TYPE_ALLOC_SRC_MASK   0x0F
#define	PBUF_ALLOC_FLAG_RX   0x0100
#define	PBUF_ALLOC_FLAG_DATA_CONTIGUOUS   0x0200
#define	PBUF_TYPE_ALLOC_SRC_MASK_APP_MIN   0x03
#define	PBUF_TYPE_ALLOC_SRC_MASK_APP_MAX   PBUF_TYPE_ALLOC_SRC_MASK
#define	PBUF_FLAG_PUSH   0x01U
#define	PBUF_FLAG_IS_CUSTOM   0x02U
#define	PBUF_FLAG_MCASTLOOP   0x04U
#define	PBUF_FLAG_LLBCAST   0x08U
#define	PBUF_FLAG_LLMCAST   0x10U
#define	PBUF_FLAG_TCP_FIN   0x20U
#define	PBUF_POOL_FREE_OOSEQ   1

Typedefs
typedef void(*	pbuf_free_custom_fn) (struct pbuf *p)

Enumerations
enum	pbuf_layer {   PBUF_TRANSPORT = 0 + (14 + 0 ) + 40 + 20, PBUF_IP = 0 + (14 + 0 ) + 40, PBUF_LINK = 0 + (14 + 0 ), PBUF_RAW_TX = 0,   PBUF_RAW = 0 }
enum	pbuf_type { PBUF_RAM = ( 0x0200 | 0x80 | 0x00 ), PBUF_ROM = 0x01, PBUF_REF = ( 0x40 | 0x01 ), PBUF_POOL = ( 0x0100 | 0x80 | 0x02 ) }

Functions
struct pbuf *	pbuf_alloc (pbuf_layer l, u16_t length, pbuf_type type)
struct pbuf *	pbuf_alloc_reference (void *payload, u16_t length, pbuf_type type)
struct pbuf *	pbuf_alloced_custom (pbuf_layer l, u16_t length, pbuf_type type, struct pbuf_custom *p, void *payload_mem, u16_t payload_mem_len)
void	pbuf_realloc (struct pbuf *p, u16_t size)
u8_t	pbuf_header (struct pbuf *p, s16_t header_size)
u8_t	pbuf_header_force (struct pbuf *p, s16_t header_size)
u8_t	pbuf_add_header (struct pbuf *p, size_t header_size_increment)
u8_t	pbuf_add_header_force (struct pbuf *p, size_t header_size_increment)
u8_t	pbuf_remove_header (struct pbuf *p, size_t header_size)
struct pbuf *	pbuf_free_header (struct pbuf *q, u16_t size)
void	pbuf_ref (struct pbuf *p)
u8_t	pbuf_free (struct pbuf *p)
u16_t	pbuf_clen (const struct pbuf *p)
void	pbuf_cat (struct pbuf *head, struct pbuf *tail)
void	pbuf_chain (struct pbuf *head, struct pbuf *tail)
struct pbuf *	pbuf_dechain (struct pbuf *p)
err_t	pbuf_copy (struct pbuf *p_to, const struct pbuf *p_from)
u16_t	pbuf_copy_partial (const struct pbuf *p, void *dataptr, u16_t len, u16_t offset)
void *	pbuf_get_contiguous (const struct pbuf *p, void *buffer, size_t bufsize, u16_t len, u16_t offset)
err_t	pbuf_take (struct pbuf *buf, const void *dataptr, u16_t len)
err_t	pbuf_take_at (struct pbuf *buf, const void *dataptr, u16_t len, u16_t offset)
struct pbuf *	pbuf_skip (struct pbuf *in, u16_t in_offset, u16_t *out_offset)
struct pbuf *	pbuf_coalesce (struct pbuf *p, pbuf_layer layer)
struct pbuf *	pbuf_clone (pbuf_layer l, pbuf_type type, struct pbuf *p)
u8_t	pbuf_get_at (const struct pbuf *p, u16_t offset)
int	pbuf_try_get_at (const struct pbuf *p, u16_t offset)
void	pbuf_put_at (struct pbuf *p, u16_t offset, u8_t data)
u16_t	pbuf_memcmp (const struct pbuf *p, u16_t offset, const void *s2, u16_t n)
u16_t	pbuf_memfind (const struct pbuf *p, const void *mem, u16_t mem_len, u16_t start_offset)
u16_t	pbuf_strstr (const struct pbuf *p, const char *substr)

Detailed Description

pbuf API

Macro Definition Documentation

LWIP_SUPPORT_CUSTOM_PBUF

#define LWIP_SUPPORT_CUSTOM_PBUF   ((IP_FRAG && !LWIP_NETIF_TX_SINGLE_PBUF) || (LWIP_IPV6 && LWIP_IPV6_FRAG))

LWIP_SUPPORT_CUSTOM_PBUF==1: Custom pbufs behave much like their pbuf type but they are allocated by external code (initialised by calling pbuf_alloced_custom()) and when pbuf_free gives up their last reference, they are freed by calling pbuf_custom->custom_free_function(). Currently, the pbuf_custom code is only needed for one specific configuration of IP_FRAG, unless required by external driver/application code.

PBUF_ALLOC_FLAG_DATA_CONTIGUOUS

#define PBUF_ALLOC_FLAG_DATA_CONTIGUOUS   0x0200

Indicates the application needs the pbuf payload to be in one piece

PBUF_ALLOC_FLAG_RX

#define PBUF_ALLOC_FLAG_RX   0x0100

Indicates this pbuf is used for RX (if not set, indicates use for TX). This information can be used to keep some spare RX buffers e.g. for receiving TCP ACKs to unblock a connection)

PBUF_FLAG_IS_CUSTOM

#define PBUF_FLAG_IS_CUSTOM   0x02U

indicates this is a custom pbuf: pbuf_free calls pbuf_custom->custom_free_function() when the last reference is released (plus custom PBUF_RAM cannot be trimmed)

PBUF_FLAG_LLBCAST

#define PBUF_FLAG_LLBCAST   0x08U

indicates this pbuf was received as link-level broadcast

PBUF_FLAG_LLMCAST

#define PBUF_FLAG_LLMCAST   0x10U

indicates this pbuf was received as link-level multicast

PBUF_FLAG_MCASTLOOP

#define PBUF_FLAG_MCASTLOOP   0x04U

indicates this pbuf is UDP multicast to be looped back

PBUF_FLAG_PUSH

#define PBUF_FLAG_PUSH   0x01U

indicates this packet's data should be immediately passed to the application

PBUF_FLAG_TCP_FIN

#define PBUF_FLAG_TCP_FIN   0x20U

indicates this pbuf includes a TCP FIN flag

PBUF_POOL_FREE_OOSEQ

#define PBUF_POOL_FREE_OOSEQ   1

Define this to 0 to prevent freeing ooseq pbufs when the PBUF_POOL is empty

PBUF_TYPE_ALLOC_SRC_MASK

#define PBUF_TYPE_ALLOC_SRC_MASK   0x0F

4 bits are reserved for 16 allocation sources (e.g. heap, pool1, pool2, etc) Internally, we use: 0=heap, 1=MEMP_PBUF, 2=MEMP_PBUF_POOL -> 13 types free

PBUF_TYPE_ALLOC_SRC_MASK_APP_MAX

#define PBUF_TYPE_ALLOC_SRC_MASK_APP_MAX   PBUF_TYPE_ALLOC_SRC_MASK

Last pbuf allocation type for applications

PBUF_TYPE_ALLOC_SRC_MASK_APP_MIN

#define PBUF_TYPE_ALLOC_SRC_MASK_APP_MIN   0x03

First pbuf allocation type for applications

PBUF_TYPE_FLAG_DATA_VOLATILE

#define PBUF_TYPE_FLAG_DATA_VOLATILE   0x40

Indicates the data stored in this pbuf can change. If this pbuf needs to be queued, it must be copied/duplicated.

PBUF_TYPE_FLAG_STRUCT_DATA_CONTIGUOUS

#define PBUF_TYPE_FLAG_STRUCT_DATA_CONTIGUOUS   0x80

Indicates that the payload directly follows the struct pbuf. This makes pbuf_header work in both directions.

Typedef Documentation

pbuf_free_custom_fn

typedef void(* pbuf_free_custom_fn) (struct pbuf *p)

Prototype for a function to free a custom pbuf

Function Documentation

pbuf_add_header()

u8_t pbuf_add_header	(	struct pbuf *	p,
		size_t	header_size_increment
	)

Adjusts the payload pointer to reveal headers in the payload.

Adjusts the ->payload pointer so that space for a header appears in the pbuf payload.

The ->payload, ->tot_len and ->len fields are adjusted.

Parameters

p	pbuf to change the header size.
header_size_increment	Number of bytes to increment header size which increases the size of the pbuf. New space is on the front. If header_size_increment is 0, this function does nothing and returns successful.

PBUF_ROM and PBUF_REF type buffers cannot have their sizes increased, so the call will fail. A check is made that the increase in header size does not move the payload pointer in front of the start of the buffer.

Returns

non-zero on failure, zero on success.

pbuf_add_header_force()

u8_t pbuf_add_header_force	(	struct pbuf *	p,
		size_t	header_size_increment
	)

Same as pbuf_add_header but does not check if 'header_size > 0' is allowed. This is used internally only, to allow PBUF_REF for RX.

pbuf_clen()

u16_t pbuf_clen

(

const struct pbuf *

p

)

Count number of pbufs in a chain

Parameters

p	first pbuf of chain

Returns

the number of pbufs in a chain

pbuf_dechain()

struct pbuf* pbuf_dechain

(

struct pbuf *

p

)

Dechains the first pbuf from its succeeding pbufs in the chain.

Makes p->tot_len field equal to p->len.

Parameters

p	pbuf to dechain

Returns

remainder of the pbuf chain, or NULL if it was de-allocated.

Note

May not be called on a packet queue.

pbuf_free_header()

struct pbuf* pbuf_free_header	(	struct pbuf *	q,
		u16_t	size
	)

Similar to pbuf_header(-size) but de-refs header pbufs for (size >= p->len)

Parameters

q	pbufs to operate on
size	The number of bytes to remove from the beginning of the pbuf list. While size >= p->len, pbufs are freed. ATTENTION: this is the opposite direction as pbuf_header, but takes an u16_t not s16_t!

Returns

the new head pbuf

pbuf_header()

u8_t pbuf_header	(	struct pbuf *	p,
		s16_t	header_size_increment
	)

Adjusts the payload pointer to hide or reveal headers in the payload.

Adjusts the ->payload pointer so that space for a header (dis)appears in the pbuf payload.

The ->payload, ->tot_len and ->len fields are adjusted.

Parameters

p	pbuf to change the header size.
header_size_increment	Number of bytes to increment header size which increases the size of the pbuf. New space is on the front. (Using a negative value decreases the header size.) If header_size_increment is 0, this function does nothing and returns successful.

PBUF_ROM and PBUF_REF type buffers cannot have their sizes increased, so the call will fail. A check is made that the increase in header size does not move the payload pointer in front of the start of the buffer.

Returns

non-zero on failure, zero on success.

pbuf_header_force()

u8_t pbuf_header_force	(	struct pbuf *	p,
		s16_t	header_size_increment
	)

Same as pbuf_header but does not check if 'header_size > 0' is allowed. This is used internally only, to allow PBUF_REF for RX.

pbuf_remove_header()

u8_t pbuf_remove_header	(	struct pbuf *	p,
		size_t	header_size_decrement
	)

Adjusts the payload pointer to hide headers in the payload.

Adjusts the ->payload pointer so that space for a header disappears in the pbuf payload.

The ->payload, ->tot_len and ->len fields are adjusted.

Parameters

p	pbuf to change the header size.
header_size_decrement	Number of bytes to decrement header size which decreases the size of the pbuf. If header_size_decrement is 0, this function does nothing and returns successful.

Returns

non-zero on failure, zero on success.

pbuf_strstr()

u16_t pbuf_strstr	(	const struct pbuf *	p,
		const char *	substr
	)

Find occurrence of substr with length substr_len in pbuf p, start at offset start_offset WARNING: in contrast to strstr(), this one does not stop at the first \0 in the pbuf/source string!

Parameters

p	pbuf to search, maximum length is 0xFFFE since 0xFFFF is used as return value 'not found'
substr	string to search for in p, maximum length is 0xFFFE

Returns

0xFFFF if substr was not found in p or the index where it was found