include/lwip/pbuf.h

0001 /*
0002  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
0003  * All rights reserved.
0004  *
0005  * Redistribution and use in source and binary forms, with or without modification,
0006  * are permitted provided that the following conditions are met:
0007  *
0008  * 1. Redistributions of source code must retain the above copyright notice,
0009  *    this list of conditions and the following disclaimer.
0010  * 2. Redistributions in binary form must reproduce the above copyright notice,
0011  *    this list of conditions and the following disclaimer in the documentation
0012  *    and/or other materials provided with the distribution.
0013  * 3. The name of the author may not be used to endorse or promote products
0014  *    derived from this software without specific prior written permission.
0015  *
0016  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
0017  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
0018  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
0019  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
0020  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
0021  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0022  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0023  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
0024  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
0025  * OF SUCH DAMAGE.
0026  *
0027  * This file is part of the lwIP TCP/IP stack.
0028  *
0029  * Author: Adam Dunkels <adam@sics.se>
0030  *
0031  */
0032
0033 #ifndef __LWIP_PBUF_H__
0034 #define __LWIP_PBUF_H__
0035
0036 #include "lwip/opt.h"
0037 #include "lwip/err.h"
0038
0039 #ifdef __cplusplus
0040 extern "C" {
0041 #endif
0042
0043 #define PBUF_TRANSPORT_HLEN 20
0044 #define PBUF_IP_HLEN        20
0045
0046 typedef enum {
0047   PBUF_TRANSPORT,
0048   PBUF_IP,
0049   PBUF_LINK,
0050   PBUF_RAW
0051 } pbuf_layer;
0052
0053 typedef enum {
0054   PBUF_RAM, /* pbuf data is stored in RAM */
0055   PBUF_ROM, /* pbuf data is stored in ROM */
0056   PBUF_REF, /* pbuf comes from the pbuf pool */
0057   PBUF_POOL /* pbuf payload refers to RAM */
0058 } pbuf_type;
0059
0060
0061 /** indicates this packet's data should be immediately passed to the application */
0062 #define PBUF_FLAG_PUSH 0x01U
0063
0064 struct pbuf {
0065   /** next pbuf in singly linked pbuf chain */
0066   struct pbuf *next;
0067
0068   /** pointer to the actual data in the buffer */
0069   void *payload;
0070
0071   /**
0072    * total length of this buffer and all next buffers in chain
0073    * belonging to the same packet.
0074    *
0075    * For non-queue packet chains this is the invariant:
0076    * p->tot_len == p->len + (p->next? p->next->tot_len: 0)
0077    */
0078   u16_t tot_len;
0079
0080   /** length of this buffer */
0081   u16_t len;
0082
0083   /** pbuf_type as u8_t instead of enum to save space */
0084   u8_t /*pbuf_type*/ type;
0085
0086   /** misc flags */
0087   u8_t flags;
0088
0089   /**
0090    * the reference count always equals the number of pointers
0091    * that refer to this pbuf. This can be pointers from an application,
0092    * the stack itself, or pbuf->next pointers from a chain.
0093    */
0094   u16_t ref;
0095
0096 };
0097
0098 /* Initializes the pbuf module. This call is empty for now, but may not be in future. */
0099 #define pbuf_init()
0100
0101 struct pbuf *pbuf_alloc(pbuf_layer l, u16_t size, pbuf_type type);
0102 void pbuf_realloc(struct pbuf *p, u16_t size);
0103 u8_t pbuf_header(struct pbuf *p, s16_t header_size);
0104 void pbuf_ref(struct pbuf *p);
0105 void pbuf_ref_chain(struct pbuf *p);
0106 u8_t pbuf_free(struct pbuf *p);
0107 u8_t pbuf_clen(struct pbuf *p);
0108 void pbuf_cat(struct pbuf *head, struct pbuf *tail);
0109 void pbuf_chain(struct pbuf *head, struct pbuf *tail);
0110 struct pbuf *pbuf_dechain(struct pbuf *p);
0111 err_t pbuf_copy(struct pbuf *p_to, struct pbuf *p_from);
0112 u16_t pbuf_copy_partial(struct pbuf *p, void *dataptr, u16_t len, u16_t offset);
0113 err_t pbuf_take(struct pbuf *buf, const void *dataptr, u16_t len);
0114 struct pbuf *pbuf_coalesce(struct pbuf *p, pbuf_layer layer);
0115
0116 #ifdef __cplusplus
0117 }
0118 #endif
0119
0120 #endif /* __LWIP_PBUF_H__ */