next up previous
Next: ICMP Up: Design and implementation Previous: Tagging outgoing packets

Tagging incoming packets

Incoming packets are received without an immediate (processual) context, and therefore must first be contextualized. The context of a packet is a connection structure mantained by Netfilter. We have extended this structure to support xid values, which are recorded for both directions of the connection. During the rest of the process, the treatment of a packet depends on the protocol as part of which it is received.