netbuf.c

00001 /**
00002  * @file
00003  * Network buffer management
00004  *
00005  */
00006  
00007 /*
00008  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
00009  * All rights reserved. 
00010  * 
00011  * Redistribution and use in source and binary forms, with or without modification, 
00012  * are permitted provided that the following conditions are met:
00013  *
00014  * 1. Redistributions of source code must retain the above copyright notice,
00015  *    this list of conditions and the following disclaimer.
00016  * 2. Redistributions in binary form must reproduce the above copyright notice,
00017  *    this list of conditions and the following disclaimer in the documentation
00018  *    and/or other materials provided with the distribution.
00019  * 3. The name of the author may not be used to endorse or promote products
00020  *    derived from this software without specific prior written permission. 
00021  *
00022  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
00023  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
00024  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
00025  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
00026  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
00027  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
00028  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
00029  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
00030  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
00031  * OF SUCH DAMAGE.
00032  *
00033  * This file is part of the lwIP TCP/IP stack.
00034  * 
00035  * Author: Adam Dunkels <adam@sics.se>
00036  *
00037  */
00038 
00039 #include "lwip/opt.h"
00040 
00041 #if LWIP_NETCONN /* don't build if not configured for use in lwipopts.h */
00042 
00043 #include "lwip/netbuf.h"
00044 #include "lwip/memp.h"
00045 
00046 #include <string.h>
00047 
00048 /**
00049  * Create (allocate) and initialize a new netbuf.
00050  * The netbuf doesn't yet contain a packet buffer!
00051  *
00052  * @return a pointer to a new netbuf
00053  *         NULL on lack of memory
00054  */
00055 struct
00056 netbuf *netbuf_new(void)
00057 {
00058   struct netbuf *buf;
00059 
00060   buf = (struct netbuf *)memp_malloc(MEMP_NETBUF);
00061   if (buf != NULL) {
00062     buf->p = NULL;
00063     buf->ptr = NULL;
00064     ip_addr_set_any(&buf->addr);
00065     buf->port = 0;
00066 #if LWIP_NETBUF_RECVINFO || LWIP_CHECKSUM_ON_COPY
00067 #if LWIP_CHECKSUM_ON_COPY
00068     buf->flags = 0;
00069 #endif /* LWIP_CHECKSUM_ON_COPY */
00070     buf->toport_chksum = 0;
00071 #if LWIP_NETBUF_RECVINFO
00072     ip_addr_set_any(&buf->toaddr);
00073 #endif /* LWIP_NETBUF_RECVINFO */
00074 #endif /* LWIP_NETBUF_RECVINFO || LWIP_CHECKSUM_ON_COPY */
00075     return buf;
00076   } else {
00077     return NULL;
00078   }
00079 }
00080 
00081 /**
00082  * Deallocate a netbuf allocated by netbuf_new().
00083  *
00084  * @param buf pointer to a netbuf allocated by netbuf_new()
00085  */
00086 void
00087 netbuf_delete(struct netbuf *buf)
00088 {
00089   if (buf != NULL) {
00090     if (buf->p != NULL) {
00091       pbuf_free(buf->p);
00092       buf->p = buf->ptr = NULL;
00093     }
00094     memp_free(MEMP_NETBUF, buf);
00095   }
00096 }
00097 
00098 /**
00099  * Allocate memory for a packet buffer for a given netbuf.
00100  *
00101  * @param buf the netbuf for which to allocate a packet buffer
00102  * @param size the size of the packet buffer to allocate
00103  * @return pointer to the allocated memory
00104  *         NULL if no memory could be allocated
00105  */
00106 void *
00107 netbuf_alloc(struct netbuf *buf, u16_t size)
00108 {
00109   LWIP_ERROR("netbuf_alloc: invalid buf", (buf != NULL), return NULL;);
00110 
00111   /* Deallocate any previously allocated memory. */
00112   if (buf->p != NULL) {
00113     pbuf_free(buf->p);
00114   }
00115   buf->p = pbuf_alloc(PBUF_TRANSPORT, size, PBUF_RAM);
00116   if (buf->p == NULL) {
00117      return NULL;
00118   }
00119   LWIP_ASSERT("check that first pbuf can hold size",
00120              (buf->p->len >= size));
00121   buf->ptr = buf->p;
00122   return buf->p->payload;
00123 }
00124 
00125 /**
00126  * Free the packet buffer included in a netbuf
00127  *
00128  * @param buf pointer to the netbuf which contains the packet buffer to free
00129  */
00130 void
00131 netbuf_free(struct netbuf *buf)
00132 {
00133   LWIP_ERROR("netbuf_free: invalid buf", (buf != NULL), return;);
00134   if (buf->p != NULL) {
00135     pbuf_free(buf->p);
00136   }
00137   buf->p = buf->ptr = NULL;
00138 }
00139 
00140 /**
00141  * Let a netbuf reference existing (non-volatile) data.
00142  *
00143  * @param buf netbuf which should reference the data
00144  * @param dataptr pointer to the data to reference
00145  * @param size size of the data
00146  * @return ERR_OK if data is referenced
00147  *         ERR_MEM if data couldn't be referenced due to lack of memory
00148  */
00149 err_t
00150 netbuf_ref(struct netbuf *buf, const void *dataptr, u16_t size)
00151 {
00152   LWIP_ERROR("netbuf_ref: invalid buf", (buf != NULL), return ERR_ARG;);
00153   if (buf->p != NULL) {
00154     pbuf_free(buf->p);
00155   }
00156   buf->p = pbuf_alloc(PBUF_TRANSPORT, 0, PBUF_REF);
00157   if (buf->p == NULL) {
00158     buf->ptr = NULL;
00159     return ERR_MEM;
00160   }
00161   buf->p->payload = (void*)dataptr;
00162   buf->p->len = buf->p->tot_len = size;
00163   buf->ptr = buf->p;
00164   return ERR_OK;
00165 }
00166 
00167 /**
00168  * Chain one netbuf to another (@see pbuf_chain)
00169  *
00170  * @param head the first netbuf
00171  * @param tail netbuf to chain after head, freed by this function, may not be reference after returning
00172  */
00173 void
00174 netbuf_chain(struct netbuf *head, struct netbuf *tail)
00175 {
00176   LWIP_ERROR("netbuf_ref: invalid head", (head != NULL), return;);
00177   LWIP_ERROR("netbuf_chain: invalid tail", (tail != NULL), return;);
00178   pbuf_cat(head->p, tail->p);
00179   head->ptr = head->p;
00180   memp_free(MEMP_NETBUF, tail);
00181 }
00182 
00183 /**
00184  * Get the data pointer and length of the data inside a netbuf.
00185  *
00186  * @param buf netbuf to get the data from
00187  * @param dataptr pointer to a void pointer where to store the data pointer
00188  * @param len pointer to an u16_t where the length of the data is stored
00189  * @return ERR_OK if the information was retreived,
00190  *         ERR_BUF on error.
00191  */
00192 err_t
00193 netbuf_data(struct netbuf *buf, void **dataptr, u16_t *len)
00194 {
00195   LWIP_ERROR("netbuf_data: invalid buf", (buf != NULL), return ERR_ARG;);
00196   LWIP_ERROR("netbuf_data: invalid dataptr", (dataptr != NULL), return ERR_ARG;);
00197   LWIP_ERROR("netbuf_data: invalid len", (len != NULL), return ERR_ARG;);
00198 
00199   if (buf->ptr == NULL) {
00200     return ERR_BUF;
00201   }
00202   *dataptr = buf->ptr->payload;
00203   *len = buf->ptr->len;
00204   return ERR_OK;
00205 }
00206 
00207 /**
00208  * Move the current data pointer of a packet buffer contained in a netbuf
00209  * to the next part.
00210  * The packet buffer itself is not modified.
00211  *
00212  * @param buf the netbuf to modify
00213  * @return -1 if there is no next part
00214  *         1  if moved to the next part but now there is no next part
00215  *         0  if moved to the next part and there are still more parts
00216  */
00217 s8_t
00218 netbuf_next(struct netbuf *buf)
00219 {
00220   LWIP_ERROR("netbuf_free: invalid buf", (buf != NULL), return -1;);
00221   if (buf->ptr->next == NULL) {
00222     return -1;
00223   }
00224   buf->ptr = buf->ptr->next;
00225   if (buf->ptr->next == NULL) {
00226     return 1;
00227   }
00228   return 0;
00229 }
00230 
00231 /**
00232  * Move the current data pointer of a packet buffer contained in a netbuf
00233  * to the beginning of the packet.
00234  * The packet buffer itself is not modified.
00235  *
00236  * @param buf the netbuf to modify
00237  */
00238 void
00239 netbuf_first(struct netbuf *buf)
00240 {
00241   LWIP_ERROR("netbuf_free: invalid buf", (buf != NULL), return;);
00242   buf->ptr = buf->p;
00243 }
00244 
00245 #endif /* LWIP_NETCONN */