1 | /**
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2 | * @file
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3 | * pbuf API
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4 | */
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5 |
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6 | /*
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7 | * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
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8 | * All rights reserved.
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9 | *
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10 | * Redistribution and use in source and binary forms, with or without modification,
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11 | * are permitted provided that the following conditions are met:
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12 | *
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13 | * 1. Redistributions of source code must retain the above copyright notice,
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14 | * this list of conditions and the following disclaimer.
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15 | * 2. Redistributions in binary form must reproduce the above copyright notice,
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16 | * this list of conditions and the following disclaimer in the documentation
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17 | * and/or other materials provided with the distribution.
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18 | * 3. The name of the author may not be used to endorse or promote products
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19 | * derived from this software without specific prior written permission.
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20 | *
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21 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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22 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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23 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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24 | * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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25 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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26 | * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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27 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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28 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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29 | * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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30 | * OF SUCH DAMAGE.
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31 | *
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32 | * This file is part of the lwIP TCP/IP stack.
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33 | *
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34 | * Author: Adam Dunkels <adam@sics.se>
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35 | *
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36 | */
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37 |
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38 | #ifndef LWIP_HDR_PBUF_H
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39 | #define LWIP_HDR_PBUF_H
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40 |
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41 | #include "lwip/opt.h"
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42 | #include "lwip/err.h"
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43 |
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44 | #ifdef __cplusplus
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45 | extern "C" {
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46 | #endif
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47 |
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48 | /** LWIP_SUPPORT_CUSTOM_PBUF==1: Custom pbufs behave much like their pbuf type
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49 | * but they are allocated by external code (initialised by calling
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50 | * pbuf_alloced_custom()) and when pbuf_free gives up their last reference, they
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51 | * are freed by calling pbuf_custom->custom_free_function().
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52 | * Currently, the pbuf_custom code is only needed for one specific configuration
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53 | * of IP_FRAG, unless required by external driver/application code. */
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54 | #ifndef LWIP_SUPPORT_CUSTOM_PBUF
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55 | #define LWIP_SUPPORT_CUSTOM_PBUF ((IP_FRAG && !LWIP_NETIF_TX_SINGLE_PBUF) || (LWIP_IPV6 && LWIP_IPV6_FRAG))
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56 | #endif
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57 |
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58 | /** @ingroup pbuf
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59 | * PBUF_NEEDS_COPY(p): return a boolean value indicating whether the given
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60 | * pbuf needs to be copied in order to be kept around beyond the current call
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61 | * stack without risking being corrupted. The default setting provides safety:
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62 | * it will make a copy iof any pbuf chain that does not consist entirely of
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63 | * PBUF_ROM type pbufs. For setups with zero-copy support, it may be redefined
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64 | * to evaluate to true in all cases, for example. However, doing so also has an
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65 | * effect on the application side: any buffers that are *not* copied must also
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66 | * *not* be reused by the application after passing them to lwIP. For example,
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67 | * when setting PBUF_NEEDS_COPY to (0), after using udp_send() with a PBUF_RAM
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68 | * pbuf, the application must free the pbuf immediately, rather than reusing it
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69 | * for other purposes. For more background information on this, see tasks #6735
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70 | * and #7896, and bugs #11400 and #49914. */
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71 | #ifndef PBUF_NEEDS_COPY
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72 | #define PBUF_NEEDS_COPY(p) ((p)->type_internal & PBUF_TYPE_FLAG_DATA_VOLATILE)
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73 | #endif /* PBUF_NEEDS_COPY */
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74 |
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75 | /* @todo: We need a mechanism to prevent wasting memory in every pbuf
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76 | (TCP vs. UDP, IPv4 vs. IPv6: UDP/IPv4 packets may waste up to 28 bytes) */
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77 |
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78 | #define PBUF_TRANSPORT_HLEN 20
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79 | #if LWIP_IPV6
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80 | #define PBUF_IP_HLEN 40
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81 | #else
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82 | #define PBUF_IP_HLEN 20
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83 | #endif
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84 |
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85 | /**
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86 | * @ingroup pbuf
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87 | * Enumeration of pbuf layers
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88 | */
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89 | typedef enum {
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90 | /** Includes spare room for transport layer header, e.g. UDP header.
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91 | * Use this if you intend to pass the pbuf to functions like udp_send().
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92 | */
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93 | PBUF_TRANSPORT = PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN,
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94 | /** Includes spare room for IP header.
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95 | * Use this if you intend to pass the pbuf to functions like raw_send().
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96 | */
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97 | PBUF_IP = PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN + PBUF_IP_HLEN,
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98 | /** Includes spare room for link layer header (ethernet header).
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99 | * Use this if you intend to pass the pbuf to functions like ethernet_output().
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100 | * @see PBUF_LINK_HLEN
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101 | */
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102 | PBUF_LINK = PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN,
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103 | /** Includes spare room for additional encapsulation header before ethernet
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104 | * headers (e.g. 802.11).
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105 | * Use this if you intend to pass the pbuf to functions like netif->linkoutput().
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106 | * @see PBUF_LINK_ENCAPSULATION_HLEN
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107 | */
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108 | PBUF_RAW_TX = PBUF_LINK_ENCAPSULATION_HLEN,
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109 | /** Use this for input packets in a netif driver when calling netif->input()
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110 | * in the most common case - ethernet-layer netif driver. */
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111 | PBUF_RAW = 0
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112 | } pbuf_layer;
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113 |
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114 |
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115 | /* Base flags for pbuf_type definitions: */
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116 |
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117 | /** Indicates that the payload directly follows the struct pbuf.
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118 | * This makes @ref pbuf_header work in both directions. */
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119 | #define PBUF_TYPE_FLAG_STRUCT_DATA_CONTIGUOUS 0x80
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120 | /** Indicates the data stored in this pbuf can change. If this pbuf needs
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121 | * to be queued, it must be copied/duplicated. */
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122 | #define PBUF_TYPE_FLAG_DATA_VOLATILE 0x40
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123 | /** 4 bits are reserved for 16 allocation sources (e.g. heap, pool1, pool2, etc)
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124 | * Internally, we use: 0=heap, 1=MEMP_PBUF, 2=MEMP_PBUF_POOL -> 13 types free*/
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125 | #define PBUF_TYPE_ALLOC_SRC_MASK 0x0F
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126 | /** Indicates this pbuf is used for RX (if not set, indicates use for TX).
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127 | * This information can be used to keep some spare RX buffers e.g. for
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128 | * receiving TCP ACKs to unblock a connection) */
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129 | #define PBUF_ALLOC_FLAG_RX 0x0100
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130 | /** Indicates the application needs the pbuf payload to be in one piece */
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131 | #define PBUF_ALLOC_FLAG_DATA_CONTIGUOUS 0x0200
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132 |
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133 | #define PBUF_TYPE_ALLOC_SRC_MASK_STD_HEAP 0x00
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134 | #define PBUF_TYPE_ALLOC_SRC_MASK_STD_MEMP_PBUF 0x01
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135 | #define PBUF_TYPE_ALLOC_SRC_MASK_STD_MEMP_PBUF_POOL 0x02
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136 | /** First pbuf allocation type for applications */
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137 | #define PBUF_TYPE_ALLOC_SRC_MASK_APP_MIN 0x03
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138 | /** Last pbuf allocation type for applications */
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139 | #define PBUF_TYPE_ALLOC_SRC_MASK_APP_MAX PBUF_TYPE_ALLOC_SRC_MASK
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140 |
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141 | /**
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142 | * @ingroup pbuf
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143 | * Enumeration of pbuf types
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144 | */
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145 | typedef enum {
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146 | /** pbuf data is stored in RAM, used for TX mostly, struct pbuf and its payload
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147 | are allocated in one piece of contiguous memory (so the first payload byte
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148 | can be calculated from struct pbuf).
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149 | pbuf_alloc() allocates PBUF_RAM pbufs as unchained pbufs (although that might
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150 | change in future versions).
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151 | This should be used for all OUTGOING packets (TX).*/
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152 | PBUF_RAM = (PBUF_ALLOC_FLAG_DATA_CONTIGUOUS | PBUF_TYPE_FLAG_STRUCT_DATA_CONTIGUOUS | PBUF_TYPE_ALLOC_SRC_MASK_STD_HEAP),
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153 | /** pbuf data is stored in ROM, i.e. struct pbuf and its payload are located in
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154 | totally different memory areas. Since it points to ROM, payload does not
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155 | have to be copied when queued for transmission. */
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156 | PBUF_ROM = PBUF_TYPE_ALLOC_SRC_MASK_STD_MEMP_PBUF,
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157 | /** pbuf comes from the pbuf pool. Much like PBUF_ROM but payload might change
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158 | so it has to be duplicated when queued before transmitting, depending on
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159 | who has a 'ref' to it. */
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160 | PBUF_REF = (PBUF_TYPE_FLAG_DATA_VOLATILE | PBUF_TYPE_ALLOC_SRC_MASK_STD_MEMP_PBUF),
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161 | /** pbuf payload refers to RAM. This one comes from a pool and should be used
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162 | for RX. Payload can be chained (scatter-gather RX) but like PBUF_RAM, struct
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163 | pbuf and its payload are allocated in one piece of contiguous memory (so
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164 | the first payload byte can be calculated from struct pbuf).
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165 | Don't use this for TX, if the pool becomes empty e.g. because of TCP queuing,
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166 | you are unable to receive TCP acks! */
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167 | PBUF_POOL = (PBUF_ALLOC_FLAG_RX | PBUF_TYPE_FLAG_STRUCT_DATA_CONTIGUOUS | PBUF_TYPE_ALLOC_SRC_MASK_STD_MEMP_PBUF_POOL)
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168 | } pbuf_type;
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169 |
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170 |
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171 | /** indicates this packet's data should be immediately passed to the application */
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172 | #define PBUF_FLAG_PUSH 0x01U
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173 | /** indicates this is a custom pbuf: pbuf_free calls pbuf_custom->custom_free_function()
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174 | when the last reference is released (plus custom PBUF_RAM cannot be trimmed) */
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175 | #define PBUF_FLAG_IS_CUSTOM 0x02U
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176 | /** indicates this pbuf is UDP multicast to be looped back */
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177 | #define PBUF_FLAG_MCASTLOOP 0x04U
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178 | /** indicates this pbuf was received as link-level broadcast */
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179 | #define PBUF_FLAG_LLBCAST 0x08U
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180 | /** indicates this pbuf was received as link-level multicast */
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181 | #define PBUF_FLAG_LLMCAST 0x10U
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182 | /** indicates this pbuf includes a TCP FIN flag */
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183 | #define PBUF_FLAG_TCP_FIN 0x20U
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184 |
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185 | /** Main packet buffer struct */
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186 | struct pbuf {
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187 | /** next pbuf in singly linked pbuf chain */
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188 | struct pbuf *next;
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189 |
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190 | /** pointer to the actual data in the buffer */
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191 | void *payload;
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192 |
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193 | /**
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194 | * total length of this buffer and all next buffers in chain
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195 | * belonging to the same packet.
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196 | *
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197 | * For non-queue packet chains this is the invariant:
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198 | * p->tot_len == p->len + (p->next? p->next->tot_len: 0)
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199 | */
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200 | u16_t tot_len;
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201 |
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202 | /** length of this buffer */
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203 | u16_t len;
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204 |
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205 | /** a bit field indicating pbuf type and allocation sources
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206 | (see PBUF_TYPE_FLAG_*, PBUF_ALLOC_FLAG_* and PBUF_TYPE_ALLOC_SRC_MASK)
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207 | */
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208 | u8_t type_internal;
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209 |
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210 | /** misc flags */
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211 | u8_t flags;
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212 |
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213 | /**
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214 | * the reference count always equals the number of pointers
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215 | * that refer to this pbuf. This can be pointers from an application,
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216 | * the stack itself, or pbuf->next pointers from a chain.
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217 | */
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218 | LWIP_PBUF_REF_T ref;
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219 |
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220 | /** For incoming packets, this contains the input netif's index */
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221 | u8_t if_idx;
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222 | };
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223 |
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224 |
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225 | /** Helper struct for const-correctness only.
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226 | * The only meaning of this one is to provide a const payload pointer
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227 | * for PBUF_ROM type.
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228 | */
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229 | struct pbuf_rom {
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230 | /** next pbuf in singly linked pbuf chain */
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231 | struct pbuf *next;
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232 |
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233 | /** pointer to the actual data in the buffer */
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234 | const void *payload;
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235 | };
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236 |
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237 | #if LWIP_SUPPORT_CUSTOM_PBUF
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238 | /** Prototype for a function to free a custom pbuf */
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239 | typedef void (*pbuf_free_custom_fn)(struct pbuf *p);
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240 |
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241 | /** A custom pbuf: like a pbuf, but following a function pointer to free it. */
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242 | struct pbuf_custom {
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243 | /** The actual pbuf */
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244 | struct pbuf pbuf;
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245 | /** This function is called when pbuf_free deallocates this pbuf(_custom) */
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246 | pbuf_free_custom_fn custom_free_function;
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247 | };
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248 | #endif /* LWIP_SUPPORT_CUSTOM_PBUF */
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249 |
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250 | /** Define this to 0 to prevent freeing ooseq pbufs when the PBUF_POOL is empty */
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251 | #ifndef PBUF_POOL_FREE_OOSEQ
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252 | #define PBUF_POOL_FREE_OOSEQ 1
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253 | #endif /* PBUF_POOL_FREE_OOSEQ */
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254 | #if LWIP_TCP && TCP_QUEUE_OOSEQ && NO_SYS && PBUF_POOL_FREE_OOSEQ
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255 | extern volatile u8_t pbuf_free_ooseq_pending;
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256 | void pbuf_free_ooseq(void);
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257 | /** When not using sys_check_timeouts(), call PBUF_CHECK_FREE_OOSEQ()
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258 | at regular intervals from main level to check if ooseq pbufs need to be
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259 | freed! */
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260 | #define PBUF_CHECK_FREE_OOSEQ() do { if(pbuf_free_ooseq_pending) { \
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261 | /* pbuf_alloc() reported PBUF_POOL to be empty -> try to free some \
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262 | ooseq queued pbufs now */ \
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263 | pbuf_free_ooseq(); }}while(0)
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264 | #else /* LWIP_TCP && TCP_QUEUE_OOSEQ && NO_SYS && PBUF_POOL_FREE_OOSEQ */
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265 | /* Otherwise declare an empty PBUF_CHECK_FREE_OOSEQ */
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266 | #define PBUF_CHECK_FREE_OOSEQ()
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267 | #endif /* LWIP_TCP && TCP_QUEUE_OOSEQ && NO_SYS && PBUF_POOL_FREE_OOSEQ*/
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268 |
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269 | /* Initializes the pbuf module. This call is empty for now, but may not be in future. */
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270 | #define pbuf_init()
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271 |
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272 | struct pbuf *pbuf_alloc(pbuf_layer l, u16_t length, pbuf_type type);
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273 | struct pbuf *pbuf_alloc_reference(void *payload, u16_t length, pbuf_type type);
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274 | #if LWIP_SUPPORT_CUSTOM_PBUF
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275 | struct pbuf *pbuf_alloced_custom(pbuf_layer l, u16_t length, pbuf_type type,
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276 | struct pbuf_custom *p, void *payload_mem,
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277 | u16_t payload_mem_len);
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278 | #endif /* LWIP_SUPPORT_CUSTOM_PBUF */
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279 | void pbuf_realloc(struct pbuf *p, u16_t size);
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280 | #define pbuf_get_allocsrc(p) ((p)->type_internal & PBUF_TYPE_ALLOC_SRC_MASK)
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281 | #define pbuf_match_allocsrc(p, type) (pbuf_get_allocsrc(p) == ((type) & PBUF_TYPE_ALLOC_SRC_MASK))
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282 | #define pbuf_match_type(p, type) pbuf_match_allocsrc(p, type)
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283 | u8_t pbuf_header(struct pbuf *p, s16_t header_size);
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284 | u8_t pbuf_header_force(struct pbuf *p, s16_t header_size);
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285 | u8_t pbuf_add_header(struct pbuf *p, size_t header_size_increment);
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286 | u8_t pbuf_add_header_force(struct pbuf *p, size_t header_size_increment);
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287 | u8_t pbuf_remove_header(struct pbuf *p, size_t header_size);
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288 | struct pbuf *pbuf_free_header(struct pbuf *q, u16_t size);
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289 | void pbuf_ref(struct pbuf *p);
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290 | u8_t pbuf_free(struct pbuf *p);
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291 | u16_t pbuf_clen(const struct pbuf *p);
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292 | void pbuf_cat(struct pbuf *head, struct pbuf *tail);
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293 | void pbuf_chain(struct pbuf *head, struct pbuf *tail);
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294 | struct pbuf *pbuf_dechain(struct pbuf *p);
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295 | err_t pbuf_copy(struct pbuf *p_to, const struct pbuf *p_from);
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296 | u16_t pbuf_copy_partial(const struct pbuf *p, void *dataptr, u16_t len, u16_t offset);
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297 | void *pbuf_get_contiguous(const struct pbuf *p, void *buffer, size_t bufsize, u16_t len, u16_t offset);
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298 | err_t pbuf_take(struct pbuf *buf, const void *dataptr, u16_t len);
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299 | err_t pbuf_take_at(struct pbuf *buf, const void *dataptr, u16_t len, u16_t offset);
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300 | struct pbuf *pbuf_skip(struct pbuf* in, u16_t in_offset, u16_t* out_offset);
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301 | struct pbuf *pbuf_coalesce(struct pbuf *p, pbuf_layer layer);
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302 | struct pbuf *pbuf_clone(pbuf_layer l, pbuf_type type, struct pbuf *p);
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303 | #if LWIP_CHECKSUM_ON_COPY
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304 | err_t pbuf_fill_chksum(struct pbuf *p, u16_t start_offset, const void *dataptr,
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305 | u16_t len, u16_t *chksum);
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306 | #endif /* LWIP_CHECKSUM_ON_COPY */
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307 | #if LWIP_TCP && TCP_QUEUE_OOSEQ && LWIP_WND_SCALE
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308 | void pbuf_split_64k(struct pbuf *p, struct pbuf **rest);
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309 | #endif /* LWIP_TCP && TCP_QUEUE_OOSEQ && LWIP_WND_SCALE */
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310 |
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311 | u8_t pbuf_get_at(const struct pbuf* p, u16_t offset);
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312 | int pbuf_try_get_at(const struct pbuf* p, u16_t offset);
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313 | void pbuf_put_at(struct pbuf* p, u16_t offset, u8_t data);
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314 | u16_t pbuf_memcmp(const struct pbuf* p, u16_t offset, const void* s2, u16_t n);
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315 | u16_t pbuf_memfind(const struct pbuf* p, const void* mem, u16_t mem_len, u16_t start_offset);
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316 | u16_t pbuf_strstr(const struct pbuf* p, const char* substr);
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317 |
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318 | #ifdef __cplusplus
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319 | }
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320 | #endif
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321 |
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322 | #endif /* LWIP_HDR_PBUF_H */
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