1 | /**
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2 | * @file
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3 | * SNMP pbuf stream wrapper implementation (internal API, do not use in client code).
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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: Martin Hentschel <info@cl-soft.de>
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35 | *
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36 | */
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37 |
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38 | #include "lwip/apps/snmp_opts.h"
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39 |
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40 | #if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */
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41 |
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42 | #include "snmp_pbuf_stream.h"
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43 | #include "lwip/def.h"
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44 | #include <string.h>
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45 |
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46 | err_t
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47 | snmp_pbuf_stream_init(struct snmp_pbuf_stream *pbuf_stream, struct pbuf *p, u16_t offset, u16_t length)
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48 | {
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49 | pbuf_stream->offset = offset;
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50 | pbuf_stream->length = length;
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51 | pbuf_stream->pbuf = p;
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52 |
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53 | return ERR_OK;
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54 | }
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55 |
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56 | err_t
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57 | snmp_pbuf_stream_read(struct snmp_pbuf_stream *pbuf_stream, u8_t *data)
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58 | {
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59 | if (pbuf_stream->length == 0) {
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60 | return ERR_BUF;
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61 | }
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62 |
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63 | if (pbuf_copy_partial(pbuf_stream->pbuf, data, 1, pbuf_stream->offset) == 0) {
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64 | return ERR_BUF;
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65 | }
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66 |
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67 | pbuf_stream->offset++;
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68 | pbuf_stream->length--;
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69 |
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70 | return ERR_OK;
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71 | }
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72 |
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73 | err_t
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74 | snmp_pbuf_stream_write(struct snmp_pbuf_stream *pbuf_stream, u8_t data)
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75 | {
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76 | return snmp_pbuf_stream_writebuf(pbuf_stream, &data, 1);
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77 | }
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78 |
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79 | err_t
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80 | snmp_pbuf_stream_writebuf(struct snmp_pbuf_stream *pbuf_stream, const void *buf, u16_t buf_len)
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81 | {
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82 | if (pbuf_stream->length < buf_len) {
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83 | return ERR_BUF;
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84 | }
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85 |
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86 | if (pbuf_take_at(pbuf_stream->pbuf, buf, buf_len, pbuf_stream->offset) != ERR_OK) {
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87 | return ERR_BUF;
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88 | }
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89 |
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90 | pbuf_stream->offset += buf_len;
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91 | pbuf_stream->length -= buf_len;
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92 |
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93 | return ERR_OK;
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94 | }
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95 |
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96 | err_t
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97 | snmp_pbuf_stream_writeto(struct snmp_pbuf_stream *pbuf_stream, struct snmp_pbuf_stream *target_pbuf_stream, u16_t len)
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98 | {
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99 |
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100 | if ((pbuf_stream == NULL) || (target_pbuf_stream == NULL)) {
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101 | return ERR_ARG;
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102 | }
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103 | if ((len > pbuf_stream->length) || (len > target_pbuf_stream->length)) {
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104 | return ERR_ARG;
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105 | }
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106 |
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107 | if (len == 0) {
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108 | len = LWIP_MIN(pbuf_stream->length, target_pbuf_stream->length);
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109 | }
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110 |
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111 | while (len > 0) {
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112 | u16_t chunk_len;
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113 | err_t err;
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114 | u16_t target_offset;
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115 | struct pbuf *pbuf = pbuf_skip(pbuf_stream->pbuf, pbuf_stream->offset, &target_offset);
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116 |
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117 | if ((pbuf == NULL) || (pbuf->len == 0)) {
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118 | return ERR_BUF;
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119 | }
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120 |
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121 | chunk_len = LWIP_MIN(len, pbuf->len);
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122 | err = snmp_pbuf_stream_writebuf(target_pbuf_stream, &((u8_t *)pbuf->payload)[target_offset], chunk_len);
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123 | if (err != ERR_OK) {
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124 | return err;
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125 | }
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126 |
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127 | pbuf_stream->offset += chunk_len;
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128 | pbuf_stream->length -= chunk_len;
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129 | len -= chunk_len;
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130 | }
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131 |
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132 | return ERR_OK;
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133 | }
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134 |
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135 | err_t
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136 | snmp_pbuf_stream_seek(struct snmp_pbuf_stream *pbuf_stream, s32_t offset)
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137 | {
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138 | if ((offset < 0) || (offset > pbuf_stream->length)) {
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139 | /* we cannot seek backwards or forward behind stream end */
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140 | return ERR_ARG;
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141 | }
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142 |
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143 | pbuf_stream->offset += (u16_t)offset;
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144 | pbuf_stream->length -= (u16_t)offset;
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145 |
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146 | return ERR_OK;
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147 | }
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148 |
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149 | err_t
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150 | snmp_pbuf_stream_seek_abs(struct snmp_pbuf_stream *pbuf_stream, u32_t offset)
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151 | {
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152 | s32_t rel_offset = offset - pbuf_stream->offset;
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153 | return snmp_pbuf_stream_seek(pbuf_stream, rel_offset);
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154 | }
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155 |
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156 | #endif /* LWIP_SNMP */
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