DHCPv4 options as list

[scufre]

Changing to store DHCPv4 options as a list instead of map and allow inserting padding options.

This is to workaround this issue https://binaryfury.wann.net/2024/12/pxe-two-tftp-filenames-one-dhcp-offer-plus-weird-filenames/ where old hardware treats the boot filename option as a null terminated string instead of relying on the option length.

To do so, the Options type was changed to be a struct with a single field that is an array of a newly created struct (optionCodeValue) having the option code and option data. And then removed a couple of cases where padding options where filtered out.
Some disclaimer on the decision to use a struct with a single field being the array of options: I'm new to go and did a try on directly declaring the Options type as an array, but then couldn't find a way of declaring those methods that need to add or remove elements in the array as that in my understanding requires creating a new array.

With these changes, now a the bootfile option can be provided and right after it, a padding option can be added, which will null terminate the string for those buggy clients.

[pmazzini]

Initially the DHCPv4 library used to have a list of option but after @hugelgupf refactor it is now a map. This fits what the RFC specifies. I am not a great fan of changing the library behaviour to make non RFC compliant clients work.

[pmazzini]

comment