[457] | 1 | /**
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| 2 | * @file
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| 3 | * Network buffer management
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| 4 | *
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| 5 | * @defgroup netbuf Network buffers
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| 6 | * @ingroup netconn
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| 7 | * Network buffer descriptor for @ref netconn. Based on @ref pbuf internally
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| 8 | * to avoid copying data around.\n
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| 9 | * Buffers must not be shared accross multiple threads, all functions except
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| 10 | * netbuf_new() and netbuf_delete() are not thread-safe.
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| 11 | */
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| 12 |
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| 13 | /*
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| 14 | * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
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| 15 | * All rights reserved.
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| 16 | *
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| 17 | * Redistribution and use in source and binary forms, with or without modification,
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| 18 | * are permitted provided that the following conditions are met:
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| 19 | *
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| 20 | * 1. Redistributions of source code must retain the above copyright notice,
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| 21 | * this list of conditions and the following disclaimer.
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| 22 | * 2. Redistributions in binary form must reproduce the above copyright notice,
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| 23 | * this list of conditions and the following disclaimer in the documentation
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| 24 | * and/or other materials provided with the distribution.
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| 25 | * 3. The name of the author may not be used to endorse or promote products
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| 26 | * derived from this software without specific prior written permission.
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| 27 | *
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| 28 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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| 29 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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| 30 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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| 31 | * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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| 32 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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| 33 | * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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| 34 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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| 35 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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| 36 | * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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| 37 | * OF SUCH DAMAGE.
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| 38 | *
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| 39 | * This file is part of the lwIP TCP/IP stack.
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| 40 | *
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| 41 | * Author: Adam Dunkels <adam@sics.se>
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| 42 | *
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| 43 | */
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| 44 |
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| 45 | #include "lwip/opt.h"
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| 46 |
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| 47 | #if LWIP_NETCONN /* don't build if not configured for use in lwipopts.h */
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| 48 |
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| 49 | #include "lwip/netbuf.h"
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| 50 | #include "lwip/memp.h"
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| 51 |
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| 52 | #include <string.h>
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| 53 |
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| 54 | /**
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| 55 | * @ingroup netbuf
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| 56 | * Create (allocate) and initialize a new netbuf.
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| 57 | * The netbuf doesn't yet contain a packet buffer!
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| 58 | *
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| 59 | * @return a pointer to a new netbuf
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| 60 | * NULL on lack of memory
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| 61 | */
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| 62 | struct
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| 63 | netbuf *netbuf_new(void)
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| 64 | {
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| 65 | struct netbuf *buf;
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| 66 |
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| 67 | buf = (struct netbuf *)memp_malloc(MEMP_NETBUF);
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| 68 | if (buf != NULL) {
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| 69 | memset(buf, 0, sizeof(struct netbuf));
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| 70 | }
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| 71 | return buf;
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| 72 | }
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| 73 |
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| 74 | /**
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| 75 | * @ingroup netbuf
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| 76 | * Deallocate a netbuf allocated by netbuf_new().
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| 77 | *
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| 78 | * @param buf pointer to a netbuf allocated by netbuf_new()
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| 79 | */
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| 80 | void
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| 81 | netbuf_delete(struct netbuf *buf)
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| 82 | {
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| 83 | if (buf != NULL) {
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| 84 | if (buf->p != NULL) {
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| 85 | pbuf_free(buf->p);
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| 86 | buf->p = buf->ptr = NULL;
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| 87 | }
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| 88 | memp_free(MEMP_NETBUF, buf);
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| 89 | }
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| 90 | }
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| 91 |
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| 92 | /**
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| 93 | * @ingroup netbuf
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| 94 | * Allocate memory for a packet buffer for a given netbuf.
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| 95 | *
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| 96 | * @param buf the netbuf for which to allocate a packet buffer
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| 97 | * @param size the size of the packet buffer to allocate
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| 98 | * @return pointer to the allocated memory
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| 99 | * NULL if no memory could be allocated
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| 100 | */
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| 101 | void *
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| 102 | netbuf_alloc(struct netbuf *buf, u16_t size)
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| 103 | {
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| 104 | LWIP_ERROR("netbuf_alloc: invalid buf", (buf != NULL), return NULL;);
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| 105 |
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| 106 | /* Deallocate any previously allocated memory. */
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| 107 | if (buf->p != NULL) {
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| 108 | pbuf_free(buf->p);
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| 109 | }
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| 110 | buf->p = pbuf_alloc(PBUF_TRANSPORT, size, PBUF_RAM);
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| 111 | if (buf->p == NULL) {
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| 112 | return NULL;
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| 113 | }
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| 114 | LWIP_ASSERT("check that first pbuf can hold size",
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| 115 | (buf->p->len >= size));
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| 116 | buf->ptr = buf->p;
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| 117 | return buf->p->payload;
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| 118 | }
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| 119 |
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| 120 | /**
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| 121 | * @ingroup netbuf
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| 122 | * Free the packet buffer included in a netbuf
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| 123 | *
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| 124 | * @param buf pointer to the netbuf which contains the packet buffer to free
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| 125 | */
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| 126 | void
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| 127 | netbuf_free(struct netbuf *buf)
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| 128 | {
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| 129 | LWIP_ERROR("netbuf_free: invalid buf", (buf != NULL), return;);
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| 130 | if (buf->p != NULL) {
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| 131 | pbuf_free(buf->p);
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| 132 | }
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| 133 | buf->p = buf->ptr = NULL;
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| 134 | #if LWIP_CHECKSUM_ON_COPY
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| 135 | buf->flags = 0;
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| 136 | buf->toport_chksum = 0;
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| 137 | #endif /* LWIP_CHECKSUM_ON_COPY */
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| 138 | }
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| 139 |
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| 140 | /**
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| 141 | * @ingroup netbuf
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| 142 | * Let a netbuf reference existing (non-volatile) data.
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| 143 | *
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| 144 | * @param buf netbuf which should reference the data
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| 145 | * @param dataptr pointer to the data to reference
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| 146 | * @param size size of the data
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| 147 | * @return ERR_OK if data is referenced
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| 148 | * ERR_MEM if data couldn't be referenced due to lack of memory
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| 149 | */
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| 150 | err_t
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| 151 | netbuf_ref(struct netbuf *buf, const void *dataptr, u16_t size)
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| 152 | {
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| 153 | LWIP_ERROR("netbuf_ref: invalid buf", (buf != NULL), return ERR_ARG;);
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| 154 | if (buf->p != NULL) {
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| 155 | pbuf_free(buf->p);
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| 156 | }
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| 157 | buf->p = pbuf_alloc(PBUF_TRANSPORT, 0, PBUF_REF);
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| 158 | if (buf->p == NULL) {
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| 159 | buf->ptr = NULL;
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| 160 | return ERR_MEM;
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| 161 | }
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| 162 | ((struct pbuf_rom *)buf->p)->payload = dataptr;
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| 163 | buf->p->len = buf->p->tot_len = size;
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| 164 | buf->ptr = buf->p;
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| 165 | return ERR_OK;
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| 166 | }
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| 167 |
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| 168 | /**
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| 169 | * @ingroup netbuf
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| 170 | * Chain one netbuf to another (@see pbuf_chain)
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| 171 | *
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| 172 | * @param head the first netbuf
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| 173 | * @param tail netbuf to chain after head, freed by this function, may not be reference after returning
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| 174 | */
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| 175 | void
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| 176 | netbuf_chain(struct netbuf *head, struct netbuf *tail)
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| 177 | {
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| 178 | LWIP_ERROR("netbuf_chain: invalid head", (head != NULL), return;);
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| 179 | LWIP_ERROR("netbuf_chain: invalid tail", (tail != NULL), return;);
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| 180 | pbuf_cat(head->p, tail->p);
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| 181 | head->ptr = head->p;
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| 182 | memp_free(MEMP_NETBUF, tail);
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| 183 | }
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| 184 |
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| 185 | /**
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| 186 | * @ingroup netbuf
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| 187 | * Get the data pointer and length of the data inside a netbuf.
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| 188 | *
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| 189 | * @param buf netbuf to get the data from
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| 190 | * @param dataptr pointer to a void pointer where to store the data pointer
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| 191 | * @param len pointer to an u16_t where the length of the data is stored
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| 192 | * @return ERR_OK if the information was retrieved,
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| 193 | * ERR_BUF on error.
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| 194 | */
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| 195 | err_t
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| 196 | netbuf_data(struct netbuf *buf, void **dataptr, u16_t *len)
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| 197 | {
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| 198 | LWIP_ERROR("netbuf_data: invalid buf", (buf != NULL), return ERR_ARG;);
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| 199 | LWIP_ERROR("netbuf_data: invalid dataptr", (dataptr != NULL), return ERR_ARG;);
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| 200 | LWIP_ERROR("netbuf_data: invalid len", (len != NULL), return ERR_ARG;);
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| 201 |
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| 202 | if (buf->ptr == NULL) {
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| 203 | return ERR_BUF;
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| 204 | }
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| 205 | *dataptr = buf->ptr->payload;
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| 206 | *len = buf->ptr->len;
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| 207 | return ERR_OK;
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| 208 | }
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| 209 |
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| 210 | /**
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| 211 | * @ingroup netbuf
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| 212 | * Move the current data pointer of a packet buffer contained in a netbuf
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| 213 | * to the next part.
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| 214 | * The packet buffer itself is not modified.
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| 215 | *
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| 216 | * @param buf the netbuf to modify
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| 217 | * @return -1 if there is no next part
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| 218 | * 1 if moved to the next part but now there is no next part
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| 219 | * 0 if moved to the next part and there are still more parts
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| 220 | */
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| 221 | s8_t
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| 222 | netbuf_next(struct netbuf *buf)
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| 223 | {
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| 224 | LWIP_ERROR("netbuf_next: invalid buf", (buf != NULL), return -1;);
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| 225 | if (buf->ptr->next == NULL) {
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| 226 | return -1;
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| 227 | }
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| 228 | buf->ptr = buf->ptr->next;
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| 229 | if (buf->ptr->next == NULL) {
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| 230 | return 1;
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| 231 | }
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| 232 | return 0;
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| 233 | }
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| 234 |
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| 235 | /**
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| 236 | * @ingroup netbuf
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| 237 | * Move the current data pointer of a packet buffer contained in a netbuf
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| 238 | * to the beginning of the packet.
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| 239 | * The packet buffer itself is not modified.
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| 240 | *
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| 241 | * @param buf the netbuf to modify
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| 242 | */
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| 243 | void
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| 244 | netbuf_first(struct netbuf *buf)
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| 245 | {
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| 246 | LWIP_ERROR("netbuf_first: invalid buf", (buf != NULL), return;);
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| 247 | buf->ptr = buf->p;
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| 248 | }
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| 249 |
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| 250 | #endif /* LWIP_NETCONN */
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