Fd.io VPP Frame forwarding diagram

After Ip4-icmp-input and ip4-udp-input can register the subsequent processing function, Ip4-icmp-input according to

The message type of the ICMP chooses the corresponding processing function, and the ip4-udp-input chooses the corresponding processing function according to the port.

The registration functions are: Ip4_icmp_register_type udp_register_dst_port

L3 Featrues's registration can be seen in my previous blog: http://www.cnblogs.com/scottieyuyang/p/5911619.html

Fd.io VPP Frame forwarding diagram