1 /**
2 * @file
3 * SNMP pbuf stream wrapper implementation (internal API, do not use in client code).
4 */
5
6 /*
7 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
8 * All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without modification,
11 * are permitted provided that the following conditions are met:
12 *
13 * 1. Redistributions of source code must retain the above copyright notice,
14 * this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright notice,
16 * this list of conditions and the following disclaimer in the documentation
17 * and/or other materials provided with the distribution.
18 * 3. The name of the author may not be used to endorse or promote products
19 * derived from this software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
22 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
23 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
24 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
25 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
26 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
29 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
30 * OF SUCH DAMAGE.
31 *
32 * This file is part of the lwIP TCP/IP stack.
33 *
34 * Author: Martin Hentschel <info@cl-soft.de>
35 *
36 */
37
38 #include "lwip/apps/snmp_opts.h"
39
40 #if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */
41
42 #include "snmp_pbuf_stream.h"
43 #include "lwip/def.h"
44 #include <string.h>
45
46 err_t
snmp_pbuf_stream_init(struct snmp_pbuf_stream * pbuf_stream,struct pbuf * p,u16_t offset,u16_t length)47 snmp_pbuf_stream_init(struct snmp_pbuf_stream* pbuf_stream, struct pbuf* p, u16_t offset, u16_t length)
48 {
49 pbuf_stream->offset = offset;
50 pbuf_stream->length = length;
51 pbuf_stream->pbuf = p;
52
53 return ERR_OK;
54 }
55
56 err_t
snmp_pbuf_stream_read(struct snmp_pbuf_stream * pbuf_stream,u8_t * data)57 snmp_pbuf_stream_read(struct snmp_pbuf_stream* pbuf_stream, u8_t* data)
58 {
59 if (pbuf_stream->length == 0) {
60 return ERR_BUF;
61 }
62
63 if (pbuf_copy_partial(pbuf_stream->pbuf, data, 1, pbuf_stream->offset) == 0) {
64 return ERR_BUF;
65 }
66
67 pbuf_stream->offset++;
68 pbuf_stream->length--;
69
70 return ERR_OK;
71 }
72
73 err_t
snmp_pbuf_stream_write(struct snmp_pbuf_stream * pbuf_stream,u8_t data)74 snmp_pbuf_stream_write(struct snmp_pbuf_stream* pbuf_stream, u8_t data)
75 {
76 return snmp_pbuf_stream_writebuf(pbuf_stream, &data, 1);
77 }
78
79 err_t
snmp_pbuf_stream_writebuf(struct snmp_pbuf_stream * pbuf_stream,const void * buf,u16_t buf_len)80 snmp_pbuf_stream_writebuf(struct snmp_pbuf_stream* pbuf_stream, const void* buf, u16_t buf_len)
81 {
82 if (pbuf_stream->length < buf_len) {
83 return ERR_BUF;
84 }
85
86 if (pbuf_take_at(pbuf_stream->pbuf, buf, buf_len, pbuf_stream->offset) != ERR_OK) {
87 return ERR_BUF;
88 }
89
90 pbuf_stream->offset += buf_len;
91 pbuf_stream->length -= buf_len;
92
93 return ERR_OK;
94 }
95
96 err_t
snmp_pbuf_stream_writeto(struct snmp_pbuf_stream * pbuf_stream,struct snmp_pbuf_stream * target_pbuf_stream,u16_t len)97 snmp_pbuf_stream_writeto(struct snmp_pbuf_stream* pbuf_stream, struct snmp_pbuf_stream* target_pbuf_stream, u16_t len)
98 {
99
100 if ((pbuf_stream == NULL) || (target_pbuf_stream == NULL)) {
101 return ERR_ARG;
102 }
103 if ((len > pbuf_stream->length) || (len > target_pbuf_stream->length)) {
104 return ERR_ARG;
105 }
106
107 if (len == 0) {
108 len = LWIP_MIN(pbuf_stream->length, target_pbuf_stream->length);
109 }
110
111 while (len > 0) {
112 u16_t chunk_len;
113 err_t err;
114 u16_t target_offset;
115 struct pbuf* pbuf = pbuf_skip(pbuf_stream->pbuf, pbuf_stream->offset, &target_offset);
116
117 if ((pbuf == NULL) || (pbuf->len == 0)) {
118 return ERR_BUF;
119 }
120
121 chunk_len = LWIP_MIN(len, pbuf->len);
122 err = snmp_pbuf_stream_writebuf(target_pbuf_stream, &((u8_t*)pbuf->payload)[target_offset], chunk_len);
123 if (err != ERR_OK) {
124 return err;
125 }
126
127 pbuf_stream->offset += chunk_len;
128 pbuf_stream->length -= chunk_len;
129 len -= chunk_len;
130 }
131
132 return ERR_OK;
133 }
134
135 err_t
snmp_pbuf_stream_seek(struct snmp_pbuf_stream * pbuf_stream,s32_t offset)136 snmp_pbuf_stream_seek(struct snmp_pbuf_stream* pbuf_stream, s32_t offset)
137 {
138 if ((offset < 0) || (offset > pbuf_stream->length)) {
139 /* we cannot seek backwards or forward behind stream end */
140 return ERR_ARG;
141 }
142
143 pbuf_stream->offset += (u16_t)offset;
144 pbuf_stream->length -= (u16_t)offset;
145
146 return ERR_OK;
147 }
148
149 err_t
snmp_pbuf_stream_seek_abs(struct snmp_pbuf_stream * pbuf_stream,u32_t offset)150 snmp_pbuf_stream_seek_abs(struct snmp_pbuf_stream* pbuf_stream, u32_t offset)
151 {
152 s32_t rel_offset = offset - pbuf_stream->offset;
153 return snmp_pbuf_stream_seek(pbuf_stream, rel_offset);
154 }
155
156 #endif /* LWIP_SNMP */
157