Evaluate olen implementation for IPv4 Options and IPv6 Extension Headers under the pnet Library

[biandratti]

In the p0f tool, the olen field is defined as: "length of IPv4 options or IPv6 extension headers. Usually zero for normal IPv4 traffic; always zero for IPv6 due to the limitations of libpcap."

The pnet library in Rust provides functionality to parse IPv4 and IPv6 packets, but it's unclear how IPv4 options (variable-length header) or IPv6 extension headers are handled and if the olen calculation can be implemented effectively.

Objective

1. Evaluate if the pnet library can provide:

• The IPv4 options length (olen) based on the IHL field.
• The total length of IPv6 extension headers.

2. Identify any limitations or gaps in the pnet implementation when compared to the behavior described in p0f.