11.6.  Obtaining dissection data

Wireshark

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11.6.  Obtaining dissection data

11.6.1. Field

A Field extractor to to obtain field values.

11.6.1.1. Field.new(fieldname)

Create a Field extractor

11.6.1.1.1. Arguments
fieldname

The filter name of the field (e.g. ip.addr)

11.6.1.1.2. Returns

The field extractor

11.6.1.1.3. Errors

  • A Field extractor must be defined before Taps or Dissectors get called

11.6.1.2. field:__call()

Obtain all values (see FieldInfo) for this field.

11.6.1.2.1. Returns

All the values of this field

11.6.1.2.2. Errors

  • Fields cannot be used outside dissectors or taps

11.6.1.3. field:__tostring()

Obtain a string with the field name

11.6.2. FieldInfo

An extracted Field

11.6.2.1. fieldinfo:__len()

Obtain the Length of the field

11.6.2.2. fieldinfo:__unm()

Obtain the Offset of the field

11.6.2.3. fieldinfo:__call()

Obtain the Value of the field

11.6.2.4. fieldinfo:__tostring()

The string representation of the field

11.6.2.5. fieldinfo:__eq()

Checks whether lhs is within rhs

11.6.2.5.1. Errors

  • Data source must be the same for both fields

11.6.2.6. fieldinfo:__le()

Checks whether the end byte of lhs is before the end of rhs

11.6.2.7. fieldinfo:__lt()

Checks whether the end byte of rhs is before the beginning of rhs

11.6.2.7.1. Errors

  • Data source must be the same for both fields

11.6.2.8. fieldinfo.name

The name of this field

11.6.2.9. fieldinfo.label

The string representing this field

11.6.2.10. fieldinfo.value

The value of this field

11.6.2.11. fieldinfo.len

The length of this field

11.6.2.12. fieldinfo.offset

The offset of this field

11.6.2.13. fieldinfo.display

The string display of this field as seen in GUI

11.6.3. Non Method Functions

11.6.3.1. all_field_infos()

Obtain all fields from the current tree. Note this only gets whatever fields the underlying * dissectors have filled in for this packet at this time - there may be fields applicable to * the packet that simply aren't being filled in because at this time they're not needed for anything. * So this function only gets what the C-side code has currently populated, not the full list.

11.6.3.1.1. Errors

  • Cannot be called outside a listener or dissector

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