Description
Multiply the data offset, from 5 through 15, by four to obtain headerBytes.
A wire-format length may count headers, payload, padding, or only part of an enclosing message. Offsets and exclusive ends must use a clearly stated byte convention.
Multiply the data offset, from 5 through 15, by four to obtain headerBytes.
When to use this tool
Use Network: TCP Data Offset Header Bytes when you need a field-level byte count or boundary check.
How to use the tool and how it works
- Enter dataOffset. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read result. Expand result to inspect the returned fields.
Multiply the data offset, from 5 through 15, by four to obtain headerBytes. Subtract the five-word base header before multiplying to obtain optionBytes.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| dataOffset | Data Offset | Required. Safe integer. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| result | Result | Required. Object. |
| result.headerBytes | Header Bytes | Calculated result member: number. |
| result.optionBytes | Option Bytes | Calculated result member: number. |
{
"input": {
"dataOffset": 6
},
"output": {
"result": {
"headerBytes": 24,
"optionBytes": 4
}
}
}Limitations and assumptions
- Option bytes include any padding; their contents are not parsed.
- Outputs are nested inside result. Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Compare the computed span with the actual captured buffer and validate its contents separately.
References
Similar or alternative tools
- TCP Option Nop End Kind Token
Map kind 0 to end-of-option-list and 1 to no-operation; both are single octets.
- Network: IPv4 Ihl Option Byte Count
Multiply IHL in 5-15 by four for headerBytes and multiply IHL minus five by four for optionBytes.