User Guide

Lua Support in Wireshark
164
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
11.6.2. 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