[457] | 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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