lib/liblwip/api/netbuf.c

   1 /**
   2  * @file
   3  * Network buffer management
   4  *
   5  */
   6
   7 /*
   8  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without modification,
  12  * are permitted provided that the following conditions are met:
  13  *
  14  * 1. Redistributions of source code must retain the above copyright notice,
  15  *    this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright notice,
  17  *    this list of conditions and the following disclaimer in the documentation
  18  *    and/or other materials provided with the distribution.
  19  * 3. The name of the author may not be used to endorse or promote products
  20  *    derived from this software without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  23  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  24  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
  25  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  26  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
  27  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  28  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  29  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  30  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
  31  * OF SUCH DAMAGE.
  32  *
  33  * This file is part of the lwIP TCP/IP stack.
  34  *
  35  * Author: Adam Dunkels <adam@sics.se>
  36  *
  37  */
  38
  39 #include "lwip/opt.h"
  40
  41 #if LWIP_NETCONN /* don't build if not configured for use in lwipopts.h */
  42
  43 #include "lwip/netbuf.h"
  44 #include "lwip/memp.h"
  45
  46 #include <string.h>
  47
  48 /**
  49  * Create (allocate) and initialize a new netbuf.
  50  * The netbuf doesn't yet contain a packet buffer!
  51  *
  52  * @return a pointer to a new netbuf
  53  *         NULL on lack of memory
  54  */
  55 struct
  56 netbuf *netbuf_new(void)
  57 {
  58   struct netbuf *buf;
  59
  60   buf = (struct netbuf *)memp_malloc(MEMP_NETBUF);
  61   if (buf != NULL) {
  62     buf->p = NULL;
  63     buf->ptr = NULL;
  64     ip_addr_set_any(&buf->addr);
  65     buf->port = 0;
  66 #if LWIP_NETBUF_RECVINFO || LWIP_CHECKSUM_ON_COPY
  67 #if LWIP_CHECKSUM_ON_COPY
  68     buf->flags = 0;
  69 #endif /* LWIP_CHECKSUM_ON_COPY */
  70     buf->toport_chksum = 0;
  71 #if LWIP_NETBUF_RECVINFO
  72     ip_addr_set_any(&buf->toaddr);
  73 #endif /* LWIP_NETBUF_RECVINFO */
  74 #endif /* LWIP_NETBUF_RECVINFO || LWIP_CHECKSUM_ON_COPY */
  75     return buf;
  76   } else {
  77     return NULL;
  78   }
  79 }
  80
  81 /**
  82  * Deallocate a netbuf allocated by netbuf_new().
  83  *
  84  * @param buf pointer to a netbuf allocated by netbuf_new()
  85  */
  86 void
  87 netbuf_delete(struct netbuf *buf)
  88 {
  89   if (buf != NULL) {
  90     if (buf->p != NULL) {
  91       pbuf_free(buf->p);
  92       buf->p = buf->ptr = NULL;
  93     }
  94     memp_free(MEMP_NETBUF, buf);
  95   }
  96 }
  97
  98 /**
  99  * Allocate memory for a packet buffer for a given netbuf.
 100  *
 101  * @param buf the netbuf for which to allocate a packet buffer
 102  * @param size the size of the packet buffer to allocate
 103  * @return pointer to the allocated memory
 104  *         NULL if no memory could be allocated
 105  */
 106 void *
 107 netbuf_alloc(struct netbuf *buf, u16_t size)
 108 {
 109   LWIP_ERROR("netbuf_alloc: invalid buf", (buf != NULL), return NULL;);
 110
 111   /* Deallocate any previously allocated memory. */
 112   if (buf->p != NULL) {
 113     pbuf_free(buf->p);
 114   }
 115   buf->p = pbuf_alloc(PBUF_TRANSPORT, size, PBUF_RAM);
 116   if (buf->p == NULL) {
 117      return NULL;
 118   }
 119   LWIP_ASSERT("check that first pbuf can hold size",
 120              (buf->p->len >= size));
 121   buf->ptr = buf->p;
 122   return buf->p->payload;
 123 }
 124
 125 /**
 126  * Free the packet buffer included in a netbuf
 127  *
 128  * @param buf pointer to the netbuf which contains the packet buffer to free
 129  */
 130 void
 131 netbuf_free(struct netbuf *buf)
 132 {
 133   LWIP_ERROR("netbuf_free: invalid buf", (buf != NULL), return;);
 134   if (buf->p != NULL) {
 135     pbuf_free(buf->p);
 136   }
 137   buf->p = buf->ptr = NULL;
 138 }
 139
 140 /**
 141  * Let a netbuf reference existing (non-volatile) data.
 142  *
 143  * @param buf netbuf which should reference the data
 144  * @param dataptr pointer to the data to reference
 145  * @param size size of the data
 146  * @return ERR_OK if data is referenced
 147  *         ERR_MEM if data couldn't be referenced due to lack of memory
 148  */
 149 err_t
 150 netbuf_ref(struct netbuf *buf, const void *dataptr, u16_t size)
 151 {
 152   LWIP_ERROR("netbuf_ref: invalid buf", (buf != NULL), return ERR_ARG;);
 153   if (buf->p != NULL) {
 154     pbuf_free(buf->p);
 155   }
 156   buf->p = pbuf_alloc(PBUF_TRANSPORT, 0, PBUF_REF);
 157   if (buf->p == NULL) {
 158     buf->ptr = NULL;
 159     return ERR_MEM;
 160   }
 161   buf->p->payload = (void*)dataptr;
 162   buf->p->len = buf->p->tot_len = size;
 163   buf->ptr = buf->p;
 164   return ERR_OK;
 165 }
 166
 167 /**
 168  * Chain one netbuf to another (@see pbuf_chain)
 169  *
 170  * @param head the first netbuf
 171  * @param tail netbuf to chain after head, freed by this function, may not be reference after returning
 172  */
 173 void
 174 netbuf_chain(struct netbuf *head, struct netbuf *tail)
 175 {
 176   LWIP_ERROR("netbuf_ref: invalid head", (head != NULL), return;);
 177   LWIP_ERROR("netbuf_chain: invalid tail", (tail != NULL), return;);
 178   pbuf_cat(head->p, tail->p);
 179   head->ptr = head->p;
 180   memp_free(MEMP_NETBUF, tail);
 181 }
 182
 183 /**
 184  * Get the data pointer and length of the data inside a netbuf.
 185  *
 186  * @param buf netbuf to get the data from
 187  * @param dataptr pointer to a void pointer where to store the data pointer
 188  * @param len pointer to an u16_t where the length of the data is stored
 189  * @return ERR_OK if the information was retreived,
 190  *         ERR_BUF on error.
 191  */
 192 err_t
 193 netbuf_data(struct netbuf *buf, void **dataptr, u16_t *len)
 194 {
 195   LWIP_ERROR("netbuf_data: invalid buf", (buf != NULL), return ERR_ARG;);
 196   LWIP_ERROR("netbuf_data: invalid dataptr", (dataptr != NULL), return ERR_ARG;);
 197   LWIP_ERROR("netbuf_data: invalid len", (len != NULL), return ERR_ARG;);
 198
 199   if (buf->ptr == NULL) {
 200     return ERR_BUF;
 201   }
 202   *dataptr = buf->ptr->payload;
 203   *len = buf->ptr->len;
 204   return ERR_OK;
 205 }
 206
 207 /**
 208  * Move the current data pointer of a packet buffer contained in a netbuf
 209  * to the next part.
 210  * The packet buffer itself is not modified.
 211  *
 212  * @param buf the netbuf to modify
 213  * @return -1 if there is no next part
 214  *         1  if moved to the next part but now there is no next part
 215  *         0  if moved to the next part and there are still more parts
 216  */
 217 s8_t
 218 netbuf_next(struct netbuf *buf)
 219 {
 220   LWIP_ERROR("netbuf_free: invalid buf", (buf != NULL), return -1;);
 221   if (buf->ptr->next == NULL) {
 222     return -1;
 223   }
 224   buf->ptr = buf->ptr->next;
 225   if (buf->ptr->next == NULL) {
 226     return 1;
 227   }
 228   return 0;
 229 }
 230
 231 /**
 232  * Move the current data pointer of a packet buffer contained in a netbuf
 233  * to the beginning of the packet.
 234  * The packet buffer itself is not modified.
 235  *
 236  * @param buf the netbuf to modify
 237  */
 238 void
 239 netbuf_first(struct netbuf *buf)
 240 {
 241   LWIP_ERROR("netbuf_free: invalid buf", (buf != NULL), return;);
 242   buf->ptr = buf->p;
 243 }
 244
 245 #endif /* LWIP_NETCONN */