pbuf.h File Reference

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

Go to the source code of this file.

Classes
struct	pbuf
struct	pbuf_rom

Macros
#define	LWIP_SUPPORT_CUSTOM_PBUF   ((IP_FRAG && !LWIP_NETIF_TX_SINGLE_PBUF) || (LWIP_IPV6 && LWIP_IPV6_FRAG))
#define	PBUF_TRANSPORT_HLEN   20
#define	PBUF_IP_HLEN   20
#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
#define	PBUF_CHECK_FREE_OOSEQ()
#define	pbuf_init()

Enumerations
enum	pbuf_layer {   PBUF_TRANSPORT, PBUF_IP, PBUF_LINK, PBUF_RAW_TX,   PBUF_RAW }
enum	pbuf_type { PBUF_RAM, PBUF_ROM, PBUF_REF, PBUF_POOL }

Functions
struct pbuf *	pbuf_alloc (pbuf_layer l, u16_t length, pbuf_type type)
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)
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)
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)
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_TRANSPORT_HLEN

#define PBUF_TRANSPORT_HLEN   20

PBUF_IP_HLEN

#define PBUF_IP_HLEN   20

PBUF_FLAG_PUSH

#define PBUF_FLAG_PUSH   0x01U

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

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_MCASTLOOP

#define PBUF_FLAG_MCASTLOOP   0x04U

indicates this pbuf is UDP multicast to be looped back

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_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_CHECK_FREE_OOSEQ

#define PBUF_CHECK_FREE_OOSEQ

(

)

pbuf_init

#define pbuf_init

(

)

Function Documentation

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 hdr_size_inc 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.

{
   return pbuf_header_impl(p, header_size_increment, 0);
}

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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.

{
   return pbuf_header_impl(p, header_size_increment, 1);
}

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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

{
  u16_t len;
 
  len = 0;
  while (p != NULL) {
    ++len;
    p = p->next;
  }
  return len;
}

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.

{
  struct pbuf *q;
  u8_t tail_gone = 1;
  /* tail */
  q = p->next;
  /* pbuf has successor in chain? */
  if (q != NULL) {
    /* assert tot_len invariant: (p->tot_len == p->len + (p->next? p->next->tot_len: 0) */
    LWIP_ASSERT("p->tot_len == p->len + q->tot_len", q->tot_len == p->tot_len - p->len);
    /* enforce invariant if assertion is disabled */
    q->tot_len = p->tot_len - p->len;
    /* decouple pbuf from remainder */
    p->next = NULL;
    /* total length of pbuf p is its own length only */
    p->tot_len = p->len;
    /* q is no longer referenced by p, free it */
    LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_dechain: unreferencing %p\n", (void *)q));
    tail_gone = pbuf_free(q);
    if (tail_gone > 0) {
      LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE,
                  ("pbuf_dechain: deallocated %p (as it is no longer referenced)\n", (void *)q));
    }
    /* return remaining tail or NULL if deallocated */
  }
  /* assert tot_len invariant: (p->tot_len == p->len + (p->next? p->next->tot_len: 0) */
  LWIP_ASSERT("p->tot_len == p->len", p->tot_len == p->len);
  return ((tail_gone > 0) ? NULL : q);
}

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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

{
  size_t substr_len;
  if ((substr == NULL) || (substr[0] == 0) || (p->tot_len == 0xFFFF)) {
    return 0xFFFF;
  }
  substr_len = strlen(substr);
  if (substr_len >= 0xFFFF) {
    return 0xFFFF;
  }
  return pbuf_memfind(p, substr, (u16_t)substr_len, 0);
}

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