246 lines
		
	
	
		
			6.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			246 lines
		
	
	
		
			6.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /**
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|  * @file
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|  * Network buffer management
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|  *
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|  */
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|  
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| /*
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|  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
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|  * All rights reserved. 
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|  * 
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|  * Redistribution and use in source and binary forms, with or without modification, 
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|  * are permitted provided that the following conditions are met:
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|  *
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|  * 1. Redistributions of source code must retain the above copyright notice,
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|  *    this list of conditions and the following disclaimer.
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|  * 2. Redistributions in binary form must reproduce the above copyright notice,
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|  *    this list of conditions and the following disclaimer in the documentation
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|  *    and/or other materials provided with the distribution.
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|  * 3. The name of the author may not be used to endorse or promote products
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|  *    derived from this software without specific prior written permission. 
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|  *
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|  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
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|  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
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|  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
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|  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
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|  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
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|  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
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|  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
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|  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
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|  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
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|  * OF SUCH DAMAGE.
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|  *
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|  * This file is part of the lwIP TCP/IP stack.
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|  * 
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|  * Author: Adam Dunkels <adam@sics.se>
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|  *
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|  */
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| 
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| #include "lwip/opt.h"
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| 
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| #if LWIP_NETCONN /* don't build if not configured for use in lwipopts.h */
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| 
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| #include "lwip/netbuf.h"
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| #include "lwip/memp.h"
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| 
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| #include <string.h>
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| 
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| /**
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|  * Create (allocate) and initialize a new netbuf.
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|  * The netbuf doesn't yet contain a packet buffer!
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|  *
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|  * @return a pointer to a new netbuf
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|  *         NULL on lack of memory
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|  */
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| struct
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| netbuf *netbuf_new(void)
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| {
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|   struct netbuf *buf;
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| 
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|   buf = (struct netbuf *)memp_malloc(MEMP_NETBUF);
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|   if (buf != NULL) {
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|     buf->p = NULL;
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|     buf->ptr = NULL;
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|     ipX_addr_set_any(LWIP_IPV6, &buf->addr);
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|     buf->port = 0;
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| #if LWIP_NETBUF_RECVINFO || LWIP_CHECKSUM_ON_COPY
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| #if LWIP_CHECKSUM_ON_COPY
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|     buf->flags = 0;
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| #endif /* LWIP_CHECKSUM_ON_COPY */
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|     buf->toport_chksum = 0;
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| #if LWIP_NETBUF_RECVINFO
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|     ipX_addr_set_any(LWIP_IPV6, &buf->toaddr);
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| #endif /* LWIP_NETBUF_RECVINFO */
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| #endif /* LWIP_NETBUF_RECVINFO || LWIP_CHECKSUM_ON_COPY */
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|     return buf;
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|   } else {
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|     return NULL;
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|   }
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| }
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| 
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| /**
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|  * Deallocate a netbuf allocated by netbuf_new().
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|  *
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|  * @param buf pointer to a netbuf allocated by netbuf_new()
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|  */
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| void
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| netbuf_delete(struct netbuf *buf)
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| {
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|   if (buf != NULL) {
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|     if (buf->p != NULL) {
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|       pbuf_free(buf->p);
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|       buf->p = buf->ptr = NULL;
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|     }
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|     memp_free(MEMP_NETBUF, buf);
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|   }
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| }
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| 
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| /**
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|  * Allocate memory for a packet buffer for a given netbuf.
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|  *
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|  * @param buf the netbuf for which to allocate a packet buffer
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|  * @param size the size of the packet buffer to allocate
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|  * @return pointer to the allocated memory
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|  *         NULL if no memory could be allocated
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|  */
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| void *
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| netbuf_alloc(struct netbuf *buf, u16_t size)
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| {
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|   LWIP_ERROR("netbuf_alloc: invalid buf", (buf != NULL), return NULL;);
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| 
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|   /* Deallocate any previously allocated memory. */
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|   if (buf->p != NULL) {
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|     pbuf_free(buf->p);
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|   }
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|   buf->p = pbuf_alloc(PBUF_TRANSPORT, size, PBUF_RAM);
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|   if (buf->p == NULL) {
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|      return NULL;
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|   }
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|   LWIP_ASSERT("check that first pbuf can hold size",
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|              (buf->p->len >= size));
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|   buf->ptr = buf->p;
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|   return buf->p->payload;
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| }
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| 
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| /**
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|  * Free the packet buffer included in a netbuf
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|  *
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|  * @param buf pointer to the netbuf which contains the packet buffer to free
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|  */
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| void
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| netbuf_free(struct netbuf *buf)
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| {
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|   LWIP_ERROR("netbuf_free: invalid buf", (buf != NULL), return;);
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|   if (buf->p != NULL) {
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|     pbuf_free(buf->p);
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|   }
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|   buf->p = buf->ptr = NULL;
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| }
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| 
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| /**
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|  * Let a netbuf reference existing (non-volatile) data.
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|  *
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|  * @param buf netbuf which should reference the data
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|  * @param dataptr pointer to the data to reference
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|  * @param size size of the data
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|  * @return ERR_OK if data is referenced
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|  *         ERR_MEM if data couldn't be referenced due to lack of memory
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|  */
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| err_t
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| netbuf_ref(struct netbuf *buf, const void *dataptr, u16_t size)
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| {
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|   LWIP_ERROR("netbuf_ref: invalid buf", (buf != NULL), return ERR_ARG;);
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|   if (buf->p != NULL) {
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|     pbuf_free(buf->p);
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|   }
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|   buf->p = pbuf_alloc(PBUF_TRANSPORT, 0, PBUF_REF);
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|   if (buf->p == NULL) {
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|     buf->ptr = NULL;
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|     return ERR_MEM;
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|   }
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|   buf->p->payload = (void*)dataptr;
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|   buf->p->len = buf->p->tot_len = size;
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|   buf->ptr = buf->p;
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|   return ERR_OK;
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| }
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| 
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| /**
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|  * Chain one netbuf to another (@see pbuf_chain)
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|  *
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|  * @param head the first netbuf
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|  * @param tail netbuf to chain after head, freed by this function, may not be reference after returning
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|  */
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| void
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| netbuf_chain(struct netbuf *head, struct netbuf *tail)
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| {
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|   LWIP_ERROR("netbuf_ref: invalid head", (head != NULL), return;);
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|   LWIP_ERROR("netbuf_chain: invalid tail", (tail != NULL), return;);
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|   pbuf_cat(head->p, tail->p);
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|   head->ptr = head->p;
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|   memp_free(MEMP_NETBUF, tail);
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| }
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| 
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| /**
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|  * Get the data pointer and length of the data inside a netbuf.
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|  *
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|  * @param buf netbuf to get the data from
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|  * @param dataptr pointer to a void pointer where to store the data pointer
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|  * @param len pointer to an u16_t where the length of the data is stored
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|  * @return ERR_OK if the information was retreived,
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|  *         ERR_BUF on error.
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|  */
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| err_t
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| netbuf_data(struct netbuf *buf, void **dataptr, u16_t *len)
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| {
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|   LWIP_ERROR("netbuf_data: invalid buf", (buf != NULL), return ERR_ARG;);
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|   LWIP_ERROR("netbuf_data: invalid dataptr", (dataptr != NULL), return ERR_ARG;);
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|   LWIP_ERROR("netbuf_data: invalid len", (len != NULL), return ERR_ARG;);
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| 
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|   if (buf->ptr == NULL) {
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|     return ERR_BUF;
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|   }
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|   *dataptr = buf->ptr->payload;
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|   *len = buf->ptr->len;
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|   return ERR_OK;
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| }
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| 
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| /**
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|  * Move the current data pointer of a packet buffer contained in a netbuf
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|  * to the next part.
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|  * The packet buffer itself is not modified.
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|  *
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|  * @param buf the netbuf to modify
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|  * @return -1 if there is no next part
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|  *         1  if moved to the next part but now there is no next part
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|  *         0  if moved to the next part and there are still more parts
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|  */
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| s8_t
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| netbuf_next(struct netbuf *buf)
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| {
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|   LWIP_ERROR("netbuf_free: invalid buf", (buf != NULL), return -1;);
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|   if (buf->ptr->next == NULL) {
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|     return -1;
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|   }
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|   buf->ptr = buf->ptr->next;
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|   if (buf->ptr->next == NULL) {
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|     return 1;
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|   }
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|   return 0;
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| }
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| 
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| /**
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|  * Move the current data pointer of a packet buffer contained in a netbuf
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|  * to the beginning of the packet.
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|  * The packet buffer itself is not modified.
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|  *
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|  * @param buf the netbuf to modify
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|  */
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| void
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| netbuf_first(struct netbuf *buf)
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| {
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|   LWIP_ERROR("netbuf_free: invalid buf", (buf != NULL), return;);
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|   buf->ptr = buf->p;
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| }
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| 
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| #endif /* LWIP_NETCONN */
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