ot::Lowpan::FragmentHeader class

Implements Fragment Header generation and parsing.

Syntax

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Summary

Declaration

from lowpan.hpp:435

class FragmentHeader { public: OT_TOOL_PACKED_BEGIN class FirstFrag { public: void Init(uint16_t aSize, uint16_t aTag) { mDispatchSize = BigEndian::HostSwap16(kFirstDispatch | (aSize & kSizeMask)); mTag = BigEndian::HostSwap16(aTag); } private: static constexpr uint16_t kFirstDispatch = 0xc000; uint16_t mDispatchSize; uint16_t mTag; } OT_TOOL_PACKED_END; OT_TOOL_PACKED_BEGIN class NextFrag { public: void Init(uint16_t aSize, uint16_t aTag, uint16_t aOffset) { mDispatchSize = BigEndian::HostSwap16(kNextDispatch | (aSize & kSizeMask)); mTag = BigEndian::HostSwap16(aTag); mOffset = static_cast<uint8_t>(aOffset >> 3); } private: static constexpr uint16_t kNextDispatch = 0xe000; uint16_t mDispatchSize; uint16_t mTag; uint8_t mOffset; } OT_TOOL_PACKED_END; static bool IsFragmentHeader(const FrameData &aFrameData); Error ParseFrom(FrameData &aFrameData); Error ParseFrom(const Message &aMessage, uint16_t aOffset, uint16_t &aHeaderLength); uint16_t GetDatagramSize(void) const { return mSize; } uint16_t GetDatagramTag(void) const { return mTag; } uint16_t GetDatagramOffset(void) const { return mOffset; } private: static constexpr uint8_t kDispatch = 0xc0; static constexpr uint8_t kDispatchMask = 0xd8; static constexpr uint8_t kOffsetFlag = 1 << 5; static constexpr uint16_t kSizeMask = 0x7ff; static constexpr uint16_t kOffsetMask = 0xfff8; static constexpr uint8_t kSizeIndex = 0; static constexpr uint8_t kTagIndex = 2; static constexpr uint8_t kOffsetIndex = 4; static bool IsFragmentHeader(const uint8_t *aFrame, uint16_t aFrameLength); Error ParseFrom(const uint8_t *aFrame, uint16_t aFrameLength, uint16_t &aHeaderLength); uint16_t mSize; uint16_t mTag; uint16_t mOffset; };

Fields

Field

Declared as

ot::Lowpan::FragmentHeader::kDispatch

ot::Lowpan::FragmentHeader::kDispatchMask

ot::Lowpan::FragmentHeader::kOffsetFlag

ot::Lowpan::FragmentHeader::kSizeMask

ot::Lowpan::FragmentHeader::kOffsetMask

ot::Lowpan::FragmentHeader::kSizeIndex

ot::Lowpan::FragmentHeader::kTagIndex

ot::Lowpan::FragmentHeader::kOffsetIndex

ot::Lowpan::FragmentHeader::mSize

uint16_t

ot::Lowpan::FragmentHeader::mTag

uint16_t

ot::Lowpan::FragmentHeader::mOffset

uint16_t

Methods

IsFragmentHeader()

Indicates whether or not the header (in a given frame) is a Fragment Header.

ParseFrom()

Parses the Fragment Header from a given frame data. If the Fragment Header is parsed successfully the @p aFrameData is updated to skip over the parsed header bytes.

ParseFrom()

Parses the Fragment Header from a given frame data. If the Fragment Header is parsed successfully the @p aFrameData is updated to skip over the parsed header bytes.

GetDatagramSize() const

Returns the Datagram Size value.

GetDatagramTag() const

Returns the Datagram Tag value.

GetDatagramOffset() const

Returns the Datagram Offset value. The returned offset value is always multiple of 8.

IsFragmentHeader()

Indicates whether or not the header (in a given frame) is a Fragment Header.

ParseFrom()

Parses the Fragment Header from a given frame data. If the Fragment Header is parsed successfully the @p aFrameData is updated to skip over the parsed header bytes.