| /* |
| * Copyright (c) 2016, The OpenThread Authors. |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * 3. Neither the name of the copyright holder nor the |
| * names of its contributors may be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
| * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE |
| * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| * POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| /** |
| * @file |
| * This file implements common methods for manipulating MLE TLVs. |
| */ |
| |
| #include "tlvs.hpp" |
| |
| #include "common/code_utils.hpp" |
| #include "common/message.hpp" |
| |
| namespace ot { |
| |
| otError Tlv::Get(const Message &aMessage, uint8_t aType, uint16_t aMaxLength, Tlv &aTlv) |
| { |
| otError error = OT_ERROR_NOT_FOUND; |
| uint16_t offset; |
| |
| SuccessOrExit(error = GetOffset(aMessage, aType, offset)); |
| aMessage.Read(offset, sizeof(Tlv), &aTlv); |
| |
| if (aMaxLength > sizeof(aTlv) + aTlv.GetLength()) |
| { |
| aMaxLength = sizeof(aTlv) + aTlv.GetLength(); |
| } |
| |
| aMessage.Read(offset, aMaxLength, &aTlv); |
| |
| exit: |
| return error; |
| } |
| |
| otError Tlv::GetOffset(const Message &aMessage, uint8_t aType, uint16_t &aOffset) |
| { |
| otError error = OT_ERROR_NOT_FOUND; |
| uint16_t offset = aMessage.GetOffset(); |
| uint16_t end = aMessage.GetLength(); |
| Tlv tlv; |
| |
| while (offset + sizeof(tlv) <= end) |
| { |
| uint32_t length = sizeof(tlv); |
| |
| aMessage.Read(offset, sizeof(tlv), &tlv); |
| |
| if (tlv.GetLength() != kExtendedLength) |
| { |
| length += tlv.GetLength(); |
| } |
| else |
| { |
| uint16_t extLength; |
| |
| VerifyOrExit(sizeof(extLength) == aMessage.Read(offset + sizeof(tlv), sizeof(extLength), &extLength)); |
| length += sizeof(extLength) + HostSwap16(extLength); |
| } |
| |
| VerifyOrExit(offset + length <= end); |
| |
| if (tlv.GetType() == aType) |
| { |
| aOffset = offset; |
| ExitNow(error = OT_ERROR_NONE); |
| } |
| |
| offset += static_cast<uint16_t>(length); |
| } |
| |
| exit: |
| return error; |
| } |
| |
| otError Tlv::GetValueOffset(const Message &aMessage, uint8_t aType, uint16_t &aOffset, uint16_t &aLength) |
| { |
| otError error = OT_ERROR_NOT_FOUND; |
| uint16_t offset = aMessage.GetOffset(); |
| uint16_t end = aMessage.GetLength(); |
| Tlv tlv; |
| |
| while (offset + sizeof(tlv) <= end) |
| { |
| uint16_t length; |
| |
| aMessage.Read(offset, sizeof(tlv), &tlv); |
| offset += sizeof(tlv); |
| length = tlv.GetLength(); |
| |
| if (length == kExtendedLength) |
| { |
| VerifyOrExit(offset + sizeof(length) <= end); |
| aMessage.Read(offset, sizeof(length), &length); |
| offset += sizeof(length); |
| length = HostSwap16(length); |
| } |
| |
| VerifyOrExit(length <= end - offset); |
| |
| if (tlv.GetType() == aType) |
| { |
| aOffset = offset; |
| aLength = length; |
| ExitNow(error = OT_ERROR_NONE); |
| } |
| |
| offset += length; |
| } |
| |
| exit: |
| return error; |
| } |
| |
| } // namespace ot |