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 /* Currently, the pbuf_custom code is only needed for one specific configuration
00044  * of IP_FRAG */
00045 #define LWIP_SUPPORT_CUSTOM_PBUF (IP_FRAG && !IP_FRAG_USES_STATIC_BUF && !LWIP_NETIF_TX_SINGLE_PBUF)
00046 
00047 #define PBUF_TRANSPORT_HLEN 20
00048 #define PBUF_IP_HLEN        20
00049 
00050 typedef enum {
00051   PBUF_TRANSPORT,
00052   PBUF_IP,
00053   PBUF_LINK,
00054   PBUF_RAW
00055 } pbuf_layer;
00056 
00057 typedef enum {
00058   PBUF_RAM, /* pbuf data is stored in RAM */
00059   PBUF_ROM, /* pbuf data is stored in ROM */
00060   PBUF_REF, /* pbuf comes from the pbuf pool */
00061   PBUF_POOL /* pbuf payload refers to RAM */
00062 } pbuf_type;
00063 
00064 
00065 /* indicates this packet's data should be immediately passed to the application */
00066 #define PBUF_FLAG_PUSH      0x01U
00067 /* indicates this is a custom pbuf: pbuf_free and pbuf_header handle such a
00068     a pbuf differently */
00069 #define PBUF_FLAG_IS_CUSTOM 0x02U
00070 /* indicates this pbuf is UDP multicast to be looped back */
00071 #define PBUF_FLAG_MCASTLOOP 0x04U
00072 
00073 struct pbuf {
00074   /* next pbuf in singly linked pbuf chain */
00075   struct pbuf *next;
00076 
00077   /* pointer to the actual data in the buffer */
00078   void *payload;
00079 
00080   /**
00081    * total length of this buffer and all next buffers in chain
00082    * belonging to the same packet.
00083    *
00084    * For non-queue packet chains this is the invariant:
00085    * p->tot_len == p->len + (p->next? p->next->tot_len: 0)
00086    */
00087   u16_t tot_len;
00088 
00089   /* length of this buffer */
00090   u16_t len;
00091 
00092   /* pbuf_type as u8_t instead of enum to save space */
00093   u8_t /*pbuf_type*/ type;
00094 
00095   /* misc flags */
00096   u8_t flags;
00097 
00098   /**
00099    * the reference count always equals the number of pointers
00100    * that refer to this pbuf. This can be pointers from an application,
00101    * the stack itself, or pbuf->next pointers from a chain.
00102    */
00103   u16_t ref;
00104 };
00105 
00106 #if LWIP_SUPPORT_CUSTOM_PBUF
00107 /* Prototype for a function to free a custom pbuf */
00108 typedef void (*pbuf_free_custom_fn)(struct pbuf *p);
00109 
00110 /* A custom pbuf: like a pbuf, but following a function pointer to free it. */
00111 struct pbuf_custom {
00112   /* The actual pbuf */
00113   struct pbuf pbuf;
00114   /* This function is called when pbuf_free deallocates this pbuf(_custom) */
00115   pbuf_free_custom_fn custom_free_function;
00116 };
00117 #endif /* LWIP_SUPPORT_CUSTOM_PBUF */
00118 
00119 /* Initializes the pbuf module. This call is empty for now, but may not be in future. */
00120 #define pbuf_init()
00121 
00122 struct pbuf *pbuf_alloc(pbuf_layer l, u16_t length, pbuf_type type);
00123 #if LWIP_SUPPORT_CUSTOM_PBUF
00124 struct pbuf *pbuf_alloced_custom(pbuf_layer l, u16_t length, pbuf_type type,
00125                                  struct pbuf_custom *p, void *payload_mem,
00126                                  u16_t payload_mem_len);
00127 #endif /* LWIP_SUPPORT_CUSTOM_PBUF */
00128 void pbuf_realloc(struct pbuf *p, u16_t size); 
00129 u8_t pbuf_header(struct pbuf *p, s16_t header_size);
00130 void pbuf_ref(struct pbuf *p);
00131 u8_t pbuf_free(struct pbuf *p);
00132 u8_t pbuf_clen(struct pbuf *p);  
00133 void pbuf_cat(struct pbuf *head, struct pbuf *tail);
00134 void pbuf_chain(struct pbuf *head, struct pbuf *tail);
00135 struct pbuf *pbuf_dechain(struct pbuf *p);
00136 err_t pbuf_copy(struct pbuf *p_to, struct pbuf *p_from);
00137 u16_t pbuf_copy_partial(struct pbuf *p, void *dataptr, u16_t len, u16_t offset);
00138 err_t pbuf_take(struct pbuf *buf, const void *dataptr, u16_t len);
00139 struct pbuf *pbuf_coalesce(struct pbuf *p, pbuf_layer layer);
00140 #if LWIP_CHECKSUM_ON_COPY
00141 err_t pbuf_fill_chksum(struct pbuf *p, u16_t start_offset, const void *dataptr,
00142                        u16_t len, u16_t *chksum);
00143 #endif /* LWIP_CHECKSUM_ON_COPY */
00144 
00145 u8_t pbuf_get_at(struct pbuf* p, u16_t offset);
00146 u16_t pbuf_memcmp(struct pbuf* p, u16_t offset, const void* s2, u16_t n);
00147 u16_t pbuf_memfind(struct pbuf* p, const void* mem, u16_t mem_len, u16_t start_offset);
00148 u16_t pbuf_strstr(struct pbuf* p, const char* substr);
00149 
00150 #ifdef __cplusplus
00151 }
00152 #endif
00153 
00154 #endif /* __LWIP_PBUF_H__ */