1 /*
2 * Copyright (c) 2016, The OpenThread Authors.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * 3. Neither the name of the copyright holder nor the
13 * names of its contributors may be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 /**
30 * @file
31 * This file implements common methods for manipulating MLE TLVs.
32 */
33
34 #include "tlvs.hpp"
35
36 #include "common/code_utils.hpp"
37 #include "common/debug.hpp"
38 #include "common/message.hpp"
39
40 namespace ot {
41
GetSize(void) const42 uint32_t Tlv::GetSize(void) const
43 {
44 return IsExtended() ? sizeof(ExtendedTlv) + As<ExtendedTlv>(this)->GetLength() : sizeof(Tlv) + GetLength();
45 }
46
GetValue(void)47 uint8_t *Tlv::GetValue(void)
48 {
49 return reinterpret_cast<uint8_t *>(this) + (IsExtended() ? sizeof(ExtendedTlv) : sizeof(Tlv));
50 }
51
GetValue(void) const52 const uint8_t *Tlv::GetValue(void) const
53 {
54 return reinterpret_cast<const uint8_t *>(this) + (IsExtended() ? sizeof(ExtendedTlv) : sizeof(Tlv));
55 }
56
AppendTo(Message & aMessage) const57 Error Tlv::AppendTo(Message &aMessage) const
58 {
59 return aMessage.AppendBytes(this, static_cast<uint16_t>(GetSize()));
60 }
61
FindTlv(const Message & aMessage,uint8_t aType,uint16_t aMaxSize,Tlv & aTlv)62 Error Tlv::FindTlv(const Message &aMessage, uint8_t aType, uint16_t aMaxSize, Tlv &aTlv)
63 {
64 Error error;
65 uint16_t offset;
66 uint16_t size;
67
68 SuccessOrExit(error = Find(aMessage, aType, &offset, &size, nullptr));
69
70 if (aMaxSize > size)
71 {
72 aMaxSize = size;
73 }
74
75 aMessage.ReadBytes(offset, &aTlv, aMaxSize);
76
77 exit:
78 return error;
79 }
80
FindTlvOffset(const Message & aMessage,uint8_t aType,uint16_t & aOffset)81 Error Tlv::FindTlvOffset(const Message &aMessage, uint8_t aType, uint16_t &aOffset)
82 {
83 return Find(aMessage, aType, &aOffset, nullptr, nullptr);
84 }
85
FindTlvValueOffset(const Message & aMessage,uint8_t aType,uint16_t & aValueOffset,uint16_t & aLength)86 Error Tlv::FindTlvValueOffset(const Message &aMessage, uint8_t aType, uint16_t &aValueOffset, uint16_t &aLength)
87 {
88 Error error;
89 uint16_t offset;
90 uint16_t size;
91 bool isExtendedTlv;
92
93 SuccessOrExit(error = Find(aMessage, aType, &offset, &size, &isExtendedTlv));
94
95 if (!isExtendedTlv)
96 {
97 aValueOffset = offset + sizeof(Tlv);
98 aLength = size - sizeof(Tlv);
99 }
100 else
101 {
102 aValueOffset = offset + sizeof(ExtendedTlv);
103 aLength = size - sizeof(ExtendedTlv);
104 }
105
106 exit:
107 return error;
108 }
109
Find(const Message & aMessage,uint8_t aType,uint16_t * aOffset,uint16_t * aSize,bool * aIsExtendedTlv)110 Error Tlv::Find(const Message &aMessage, uint8_t aType, uint16_t *aOffset, uint16_t *aSize, bool *aIsExtendedTlv)
111 {
112 // This static method searches within a `aMessage` for a TLV type
113 // `aType` and outputs the TLV offset, size, and whether or not it
114 // is an Extended TLV.
115 //
116 // A `nullptr` pointer can be used for output parameters `aOffset`,
117 // `aSize`, or `aIsExtendedTlv` if the parameter is not required.
118 //
119 // Returns `kErrorNone` when found, otherwise `kErrorNotFound`.
120
121 Error error = kErrorNotFound;
122 uint16_t offset = aMessage.GetOffset();
123 uint16_t remainingLen = aMessage.GetLength();
124 Tlv tlv;
125 uint32_t size;
126
127 VerifyOrExit(offset <= remainingLen);
128 remainingLen -= offset;
129
130 while (true)
131 {
132 SuccessOrExit(aMessage.Read(offset, tlv));
133
134 if (tlv.mLength != kExtendedLength)
135 {
136 size = tlv.GetSize();
137 }
138 else
139 {
140 ExtendedTlv extTlv;
141
142 SuccessOrExit(aMessage.Read(offset, extTlv));
143
144 VerifyOrExit(extTlv.GetLength() <= (remainingLen - sizeof(ExtendedTlv)));
145 size = extTlv.GetSize();
146 }
147
148 VerifyOrExit(size <= remainingLen);
149
150 if (tlv.GetType() == aType)
151 {
152 if (aOffset != nullptr)
153 {
154 *aOffset = offset;
155 }
156
157 if (aSize != nullptr)
158 {
159 *aSize = static_cast<uint16_t>(size);
160 }
161
162 if (aIsExtendedTlv != nullptr)
163 {
164 *aIsExtendedTlv = (tlv.mLength == kExtendedLength);
165 }
166
167 error = kErrorNone;
168 ExitNow();
169 }
170
171 offset += size;
172 remainingLen -= size;
173 }
174
175 exit:
176 return error;
177 }
178
ReadUintTlv(const Message & aMessage,uint16_t aOffset,UintType & aValue)179 template <typename UintType> Error Tlv::ReadUintTlv(const Message &aMessage, uint16_t aOffset, UintType &aValue)
180 {
181 Error error;
182
183 SuccessOrExit(error = ReadTlv(aMessage, aOffset, &aValue, sizeof(aValue)));
184 aValue = Encoding::BigEndian::HostSwap<UintType>(aValue);
185
186 exit:
187 return error;
188 }
189
190 // Explicit instantiations of `ReadUintTlv<>()`
191 template Error Tlv::ReadUintTlv<uint8_t>(const Message &aMessage, uint16_t aOffset, uint8_t &aValue);
192 template Error Tlv::ReadUintTlv<uint16_t>(const Message &aMessage, uint16_t aOffset, uint16_t &aValue);
193 template Error Tlv::ReadUintTlv<uint32_t>(const Message &aMessage, uint16_t aOffset, uint32_t &aValue);
194
ReadTlv(const Message & aMessage,uint16_t aOffset,void * aValue,uint8_t aMinLength)195 Error Tlv::ReadTlv(const Message &aMessage, uint16_t aOffset, void *aValue, uint8_t aMinLength)
196 {
197 Error error = kErrorNone;
198 Tlv tlv;
199
200 SuccessOrExit(error = aMessage.Read(aOffset, tlv));
201 VerifyOrExit(!tlv.IsExtended() && (tlv.GetLength() >= aMinLength), error = kErrorParse);
202 VerifyOrExit(tlv.GetSize() + aOffset <= aMessage.GetLength(), error = kErrorParse);
203
204 aMessage.ReadBytes(aOffset + sizeof(Tlv), aValue, aMinLength);
205
206 exit:
207 return error;
208 }
209
FindUintTlv(const Message & aMessage,uint8_t aType,UintType & aValue)210 template <typename UintType> Error Tlv::FindUintTlv(const Message &aMessage, uint8_t aType, UintType &aValue)
211 {
212 Error error = kErrorNone;
213 uint16_t offset;
214
215 SuccessOrExit(error = FindTlvOffset(aMessage, aType, offset));
216 error = ReadUintTlv<UintType>(aMessage, offset, aValue);
217
218 exit:
219 return error;
220 }
221
222 // Explicit instantiations of `FindUintTlv<>()`
223 template Error Tlv::FindUintTlv<uint8_t>(const Message &aMessage, uint8_t aType, uint8_t &aValue);
224 template Error Tlv::FindUintTlv<uint16_t>(const Message &aMessage, uint8_t aType, uint16_t &aValue);
225 template Error Tlv::FindUintTlv<uint32_t>(const Message &aMessage, uint8_t aType, uint32_t &aValue);
226
FindTlv(const Message & aMessage,uint8_t aType,void * aValue,uint8_t aLength)227 Error Tlv::FindTlv(const Message &aMessage, uint8_t aType, void *aValue, uint8_t aLength)
228 {
229 Error error;
230 uint16_t offset;
231 uint16_t length;
232
233 SuccessOrExit(error = FindTlvValueOffset(aMessage, aType, offset, length));
234 VerifyOrExit(length >= aLength, error = kErrorParse);
235 aMessage.ReadBytes(offset, aValue, aLength);
236
237 exit:
238 return error;
239 }
240
AppendUintTlv(Message & aMessage,uint8_t aType,UintType aValue)241 template <typename UintType> Error Tlv::AppendUintTlv(Message &aMessage, uint8_t aType, UintType aValue)
242 {
243 UintType value = Encoding::BigEndian::HostSwap<UintType>(aValue);
244
245 return AppendTlv(aMessage, aType, &value, sizeof(UintType));
246 }
247
248 // Explicit instantiations of `AppendUintTlv<>()`
249 template Error Tlv::AppendUintTlv<uint8_t>(Message &aMessage, uint8_t aType, uint8_t aValue);
250 template Error Tlv::AppendUintTlv<uint16_t>(Message &aMessage, uint8_t aType, uint16_t aValue);
251 template Error Tlv::AppendUintTlv<uint32_t>(Message &aMessage, uint8_t aType, uint32_t aValue);
252
AppendTlv(Message & aMessage,uint8_t aType,const void * aValue,uint8_t aLength)253 Error Tlv::AppendTlv(Message &aMessage, uint8_t aType, const void *aValue, uint8_t aLength)
254 {
255 Error error = kErrorNone;
256 Tlv tlv;
257
258 OT_ASSERT(aLength <= Tlv::kBaseTlvMaxLength);
259
260 tlv.SetType(aType);
261 tlv.SetLength(aLength);
262 SuccessOrExit(error = aMessage.Append(tlv));
263
264 VerifyOrExit(aLength > 0);
265 error = aMessage.AppendBytes(aValue, aLength);
266
267 exit:
268 return error;
269 }
270
271 } // namespace ot
272