Motivation:
At the moment our AbstractSniHandler makes the assemption that Handshake messages are not fragmented. This is incorrect as it is completely valid to split these across multiple TLSPlaintext records.
Thanks to @sskrobotov for bringing this to my attentation and to @Lukasa for the help.
Modifications:
- Adjust logic in AbstractSniHandler to handle fragmentation
- Add unit tests
Result:
Correctly handle fragmented Handshake message in AbstractSniHandler (and so SniHandler).