lib/liblwip/include/lwip/pbuf.h

   1 /*
   2  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without modification,
   6  * are permitted provided that the following conditions are met:
   7  *
   8  * 1. Redistributions of source code must retain the above copyright notice,
   9  *    this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright notice,
  11  *    this list of conditions and the following disclaimer in the documentation
  12  *    and/or other materials provided with the distribution.
  13  * 3. The name of the author may not be used to endorse or promote products
  14  *    derived from this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
  19  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  20  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
  21  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  22  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  23  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  24  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
  25  * OF SUCH DAMAGE.
  26  *
  27  * This file is part of the lwIP TCP/IP stack.
  28  *
  29  * Author: Adam Dunkels <adam@sics.se>
  30  *
  31  */
  32
  33 #ifndef __LWIP_PBUF_H__
  34 #define __LWIP_PBUF_H__
  35
  36 #include "lwip/opt.h"
  37 #include "lwip/err.h"
  38
  39 #ifdef __cplusplus
  40 extern "C" {
  41 #endif
  42
  43 /** Currently, the pbuf_custom code is only needed for one specific configuration
  44  * of IP_FRAG */
  45 #define LWIP_SUPPORT_CUSTOM_PBUF (IP_FRAG && !IP_FRAG_USES_STATIC_BUF && !LWIP_NETIF_TX_SINGLE_PBUF)
  46
  47 #define PBUF_TRANSPORT_HLEN 20
  48 #define PBUF_IP_HLEN        20
  49
  50 typedef enum {
  51   PBUF_TRANSPORT,
  52   PBUF_IP,
  53   PBUF_LINK,
  54   PBUF_RAW
  55 } pbuf_layer;
  56
  57 typedef enum {
  58   PBUF_RAM, /* pbuf data is stored in RAM */
  59   PBUF_ROM, /* pbuf data is stored in ROM */
  60   PBUF_REF, /* pbuf comes from the pbuf pool */
  61   PBUF_POOL /* pbuf payload refers to RAM */
  62 } pbuf_type;
  63
  64
  65 /** indicates this packet's data should be immediately passed to the application */
  66 #define PBUF_FLAG_PUSH      0x01U
  67 /** indicates this is a custom pbuf: pbuf_free and pbuf_header handle such a
  68     a pbuf differently */
  69 #define PBUF_FLAG_IS_CUSTOM 0x02U
  70 /** indicates this pbuf is UDP multicast to be looped back */
  71 #define PBUF_FLAG_MCASTLOOP 0x04U
  72
  73 struct pbuf {
  74   /** next pbuf in singly linked pbuf chain */
  75   struct pbuf *next;
  76
  77   /** pointer to the actual data in the buffer */
  78   void *payload;
  79
  80   /**
  81    * total length of this buffer and all next buffers in chain
  82    * belonging to the same packet.
  83    *
  84    * For non-queue packet chains this is the invariant:
  85    * p->tot_len == p->len + (p->next? p->next->tot_len: 0)
  86    */
  87   u16_t tot_len;
  88
  89   /** length of this buffer */
  90   u16_t len;
  91
  92   /** pbuf_type as u8_t instead of enum to save space */
  93   u8_t /*pbuf_type*/ type;
  94
  95   /** misc flags */
  96   u8_t flags;
  97
  98   /**
  99    * the reference count always equals the number of pointers
 100    * that refer to this pbuf. This can be pointers from an application,
 101    * the stack itself, or pbuf->next pointers from a chain.
 102    */
 103   u16_t ref;
 104 };
 105
 106 #if LWIP_SUPPORT_CUSTOM_PBUF
 107 /** Prototype for a function to free a custom pbuf */
 108 typedef void (*pbuf_free_custom_fn)(struct pbuf *p);
 109
 110 /** A custom pbuf: like a pbuf, but following a function pointer to free it. */
 111 struct pbuf_custom {
 112   /** The actual pbuf */
 113   struct pbuf pbuf;
 114   /** This function is called when pbuf_free deallocates this pbuf(_custom) */
 115   pbuf_free_custom_fn custom_free_function;
 116 };
 117 #endif /* LWIP_SUPPORT_CUSTOM_PBUF */
 118
 119 /* Initializes the pbuf module. This call is empty for now, but may not be in future. */
 120 #define pbuf_init()
 121
 122 struct pbuf *pbuf_alloc(pbuf_layer l, u16_t length, pbuf_type type);
 123 #if LWIP_SUPPORT_CUSTOM_PBUF
 124 struct pbuf *pbuf_alloced_custom(pbuf_layer l, u16_t length, pbuf_type type,
 125                                  struct pbuf_custom *p, void *payload_mem,
 126                                  u16_t payload_mem_len);
 127 #endif /* LWIP_SUPPORT_CUSTOM_PBUF */
 128 void pbuf_realloc(struct pbuf *p, u16_t size);
 129 u8_t pbuf_header(struct pbuf *p, s16_t header_size);
 130 void pbuf_ref(struct pbuf *p);
 131 u8_t pbuf_free(struct pbuf *p);
 132 u8_t pbuf_clen(struct pbuf *p);
 133 void pbuf_cat(struct pbuf *head, struct pbuf *tail);
 134 void pbuf_chain(struct pbuf *head, struct pbuf *tail);
 135 struct pbuf *pbuf_dechain(struct pbuf *p);
 136 err_t pbuf_copy(struct pbuf *p_to, struct pbuf *p_from);
 137 u16_t pbuf_copy_partial(struct pbuf *p, void *dataptr, u16_t len, u16_t offset);
 138 err_t pbuf_take(struct pbuf *buf, const void *dataptr, u16_t len);
 139 struct pbuf *pbuf_coalesce(struct pbuf *p, pbuf_layer layer);
 140 #if LWIP_CHECKSUM_ON_COPY
 141 err_t pbuf_fill_chksum(struct pbuf *p, u16_t start_offset, const void *dataptr,
 142                        u16_t len, u16_t *chksum);
 143 #endif /* LWIP_CHECKSUM_ON_COPY */
 144
 145 u8_t pbuf_get_at(struct pbuf* p, u16_t offset);
 146 u16_t pbuf_memcmp(struct pbuf* p, u16_t offset, const void* s2, u16_t n);
 147 u16_t pbuf_memfind(struct pbuf* p, const void* mem, u16_t mem_len, u16_t start_offset);
 148 u16_t pbuf_strstr(struct pbuf* p, const char* substr);
 149
 150 #ifdef __cplusplus
 151 }
 152 #endif
 153
 154 #endif /* __LWIP_PBUF_H__ */