A new ICMPResponder interface is introduced to provide different
implementations of how the ICMP flows should return to the QUIC
connection muxer.
Improves usages of netip.AddrPort to leverage the embedded zone
field for IPv6 addresses.
Closes TUN-8640
Remove send and return methods from Funnel interface. Users of Funnel can provide their own send and return methods without wrapper to comply with the interface.
Move packet router to ingress package to avoid circular dependency
A funnel is an abstraction for 1 source to many destinations.
As part of this refactoring, shared logic between Darwin and Linux are moved into icmp_posix
Devin Carr
cthuang