Some hosts use iptables and are configured to respond an ICMP destination
unreachable message with a {host/net/admin}prohibited code instead of a RST.
Linux handles these codes correctly by aborting the handshake. This commit
adds handling of all possible codes of an ICMPv4 destination unreachable message
to bring gVisor to parity.
PiperOrigin-RevId: 496703813
ErrNoRoute gets translated to EHOSTUNREACH which causes some code paths to
produce different errors unexpectedly. Rename the error so we can clean up some
sites to return ENETUNREACH more clearly where needed.
Updates #8105
PiperOrigin-RevId: 482355099
This change implements AddMulticastRoute and the requisite routing logic.
Subsequent changes will still be needed to:
1. Emit events for missing route or unexpected input interface
2. Implement DelRoute
3. Implement GetRouteStats
Updates #7338.
PiperOrigin-RevId: 451026594
