Extension Header Option Length Is Single Byte

[hawkinsw]

Based on my reading of RFC8200, I think that the length of an option header is a single byte (Section 4.2). It would appear that ipv6toolkit treats it as two bytes. I have a PR for a fix (if my analysis is correct): #102

I hope that this feedback and PR helps!

[hawkinsw]

Again, @fgont , thank you for doing such great work with ipv6toolkit! I hope that this report and little PR is helpful!