i386/MIT/course/src/src.lab/net/lwip/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 #define PBUF_TRANSPORT_HLEN 20
  44 #define PBUF_IP_HLEN        20
  45
  46 typedef enum {
  47   PBUF_TRANSPORT,
  48   PBUF_IP,
  49   PBUF_LINK,
  50   PBUF_RAW
  51 } pbuf_layer;
  52
  53 typedef enum {
  54   PBUF_RAM, /* pbuf data is stored in RAM */
  55   PBUF_ROM, /* pbuf data is stored in ROM */
  56   PBUF_REF, /* pbuf comes from the pbuf pool */
  57   PBUF_POOL /* pbuf payload refers to RAM */
  58 } pbuf_type;
  59
  60
  61 /** indicates this packet's data should be immediately passed to the application */
  62 #define PBUF_FLAG_PUSH 0x01U
  63
  64 struct pbuf {
  65   /** next pbuf in singly linked pbuf chain */
  66   struct pbuf *next;
  67
  68   /** pointer to the actual data in the buffer */
  69   void *payload;
  70
  71   /**
  72    * total length of this buffer and all next buffers in chain
  73    * belonging to the same packet.
  74    *
  75    * For non-queue packet chains this is the invariant:
  76    * p->tot_len == p->len + (p->next? p->next->tot_len: 0)
  77    */
  78   u16_t tot_len;
  79
  80   /** length of this buffer */
  81   u16_t len;
  82
  83   /** pbuf_type as u8_t instead of enum to save space */
  84   u8_t /*pbuf_type*/ type;
  85
  86   /** misc flags */
  87   u8_t flags;
  88
  89   /**
  90    * the reference count always equals the number of pointers
  91    * that refer to this pbuf. This can be pointers from an application,
  92    * the stack itself, or pbuf->next pointers from a chain.
  93    */
  94   u16_t ref;
  95
  96 };
  97
  98 /* Initializes the pbuf module. This call is empty for now, but may not be in future. */
  99 #define pbuf_init()
 100
 101 struct pbuf *pbuf_alloc(pbuf_layer l, u16_t size, pbuf_type type);
 102 void pbuf_realloc(struct pbuf *p, u16_t size);
 103 u8_t pbuf_header(struct pbuf *p, s16_t header_size);
 104 void pbuf_ref(struct pbuf *p);
 105 void pbuf_ref_chain(struct pbuf *p);
 106 u8_t pbuf_free(struct pbuf *p);
 107 u8_t pbuf_clen(struct pbuf *p);
 108 void pbuf_cat(struct pbuf *head, struct pbuf *tail);
 109 void pbuf_chain(struct pbuf *head, struct pbuf *tail);
 110 struct pbuf *pbuf_dechain(struct pbuf *p);
 111 err_t pbuf_copy(struct pbuf *p_to, struct pbuf *p_from);
 112 u16_t pbuf_copy_partial(struct pbuf *p, void *dataptr, u16_t len, u16_t offset);
 113
 114 #ifdef __cplusplus
 115 }
 116 #endif
 117
 118 #endif /* __LWIP_PBUF_H__ */