mami-project
TCP options parsing doesn't support an option appearing more than once
If the TCP options parser sees the same option multiple times, the last one will win. This is not a problem for TFO as specified, but it may be for future things we want to observe with the same options parser (e.g. MPTCP, TCPENO).
# copy options data into hash
# FIXME doesn't handle multiples
opthash[optbytes[cp]] = optbytes[cp+2:ncp]
"multiples" here means "a TCP option that appears multiple times" -- if this parser sees the same option multiple times, the last one will win. This is not a problem for TFO as specified, but it may be for future things we want to observe with the same options parser (e.g. MPTCP, TCPENO).
Ok, now I've read the code I understand this a lot better. The option number is used as a hash index which then means that there can only be one. Instead, the option number can be used as a hash index for an array which contains the contents as long as this doesn't cause a massive decrease in performance. If it does, we can selectively do that for options that we think would have multiples.