pbuf.h

00001 /*
00002  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
00003  * All rights reserved. 
00004  * 
00005  * Redistribution and use in source and binary forms, with or without modification, 
00006  * are permitted provided that the following conditions are met:
00007  *
00008  * 1. Redistributions of source code must retain the above copyright notice,
00009  *    this list of conditions and the following disclaimer.
00010  * 2. Redistributions in binary form must reproduce the above copyright notice,
00011  *    this list of conditions and the following disclaimer in the documentation
00012  *    and/or other materials provided with the distribution.
00013  * 3. The name of the author may not be used to endorse or promote products
00014  *    derived from this software without specific prior written permission. 
00015  *
00016  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
00017  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
00018  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
00019  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
00020  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
00021  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
00022  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
00023  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
00024  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
00025  * OF SUCH DAMAGE.
00026  *
00027  * This file is part of the lwIP TCP/IP stack.
00028  * 
00029  * Author: Adam Dunkels <adam@sics.se>
00030  *
00031  */
00032 
00033 #ifndef __LWIP_PBUF_H__
00034 #define __LWIP_PBUF_H__
00035 
00036 #include "lwip/opt.h"
00037 #include "lwip/err.h"
00038 
00039 #ifdef __cplusplus
00040 extern "C" {
00041 #endif
00042 
00043 #define PBUF_TRANSPORT_HLEN 20
00044 #define PBUF_IP_HLEN        20
00045 
00046 typedef enum {
00047   PBUF_TRANSPORT,
00048   PBUF_IP,
00049   PBUF_LINK,
00050   PBUF_RAW
00051 } pbuf_layer;
00052 
00053 typedef enum {
00054   PBUF_RAM, /* pbuf data is stored in RAM */
00055   PBUF_ROM, /* pbuf data is stored in ROM */
00056   PBUF_REF, /* pbuf comes from the pbuf pool */
00057   PBUF_POOL /* pbuf payload refers to RAM */
00058 } pbuf_type;
00059 
00060 
00061 /** indicates this packet's data should be immediately passed to the application */
00062 #define PBUF_FLAG_PUSH 0x01U
00063 
00064 struct pbuf {
00065   /** next pbuf in singly linked pbuf chain */
00066   struct pbuf *next;
00067 
00068   /** pointer to the actual data in the buffer */
00069   void *payload;
00070   
00071   /**
00072    * total length of this buffer and all next buffers in chain
00073    * belonging to the same packet.
00074    *
00075    * For non-queue packet chains this is the invariant:
00076    * p->tot_len == p->len + (p->next? p->next->tot_len: 0)
00077    */
00078   u16_t tot_len;
00079   
00080   /** length of this buffer */
00081   u16_t len;  
00082 
00083   /** pbuf_type as u8_t instead of enum to save space */
00084   u8_t /*pbuf_type*/ type;
00085 
00086   /** misc flags */
00087   u8_t flags;
00088 
00089   /**
00090    * the reference count always equals the number of pointers
00091    * that refer to this pbuf. This can be pointers from an application,
00092    * the stack itself, or pbuf->next pointers from a chain.
00093    */
00094   u16_t ref;
00095   
00096 };
00097 
00098 /* Initializes the pbuf module. This call is empty for now, but may not be in future. */
00099 #define pbuf_init()
00100 
00101 struct pbuf *pbuf_alloc(pbuf_layer l, u16_t size, pbuf_type type);
00102 void pbuf_realloc(struct pbuf *p, u16_t size); 
00103 u8_t pbuf_header(struct pbuf *p, s16_t header_size);
00104 void pbuf_ref(struct pbuf *p);
00105 void pbuf_ref_chain(struct pbuf *p);
00106 u8_t pbuf_free(struct pbuf *p);
00107 u8_t pbuf_clen(struct pbuf *p);  
00108 void pbuf_cat(struct pbuf *head, struct pbuf *tail);
00109 void pbuf_chain(struct pbuf *head, struct pbuf *tail);
00110 struct pbuf *pbuf_dechain(struct pbuf *p);
00111 err_t pbuf_copy(struct pbuf *p_to, struct pbuf *p_from);
00112 u16_t pbuf_copy_partial(struct pbuf *p, void *dataptr, u16_t len, u16_t offset);
00113 
00114 #ifdef __cplusplus
00115 }
00116 #endif
00117 
00118 #endif /* __LWIP_PBUF_H__ */