tcp::collect
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TCP::collect and large TLS v1.3 client hello packets
Is anyone using iRules successfully to parse SNI names from the new TLS 1.3 hybridized Kyber client hello packets? The problem is the these packets are larger than MTU(?) size, around ~1800 bytes. Normal hello packets are ~500 bytes. I'm using TCP profile for which iRule parses SNI name to pass the connection as is to correct destination pool. How to reproduce: when CLIENT_ACCEPTED { TCP::collect } when CLIENT_DATA { # [TCP::payload length] shows only 1352, rest of packet missing, CLIENT_DATA is never called again } It only ever gets the first ~1352 bytes from packet, CLIENT_DATA is only called once, seems there is no way to get rest of the packet. If I add argument to collect length >1500 with "TCP::collect 1600", then it will read the whole ~1800 byte packet in first CLIENT_DATA. But this will break all connections that send normal small ~500 byte hello packets, as it just keeps on waiting for data indefinitely. Is there any workaround? BIG-IP version 16.1.4.1.Solved145Views0likes4Comments