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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