[推荐文章三]Inside the Linux Packet Filter, Part II

In the last issue we started following a packet's journey from the wire up to the higher levels of network stack processing. We left the packet at the end of layer 3 processing, where IP has completely finished its work and is going to pass the packet to either TCP or UDP. In this article, we complete our analysis by considering layer 4, the PF_PACKET protocol implementation and the socket filter hooks.

Apart from the case of IGMP and ICMP processing, which is dealt with in the……