ICMPv4 message

ICMPv4 message
1. Why is there a restriction on the generation of an ICMPv4 message in response to a failed ICMPv4 error message?
2. What is the purpose of including the IPv4 header and the first 8 bytes of datagram data in the error-reporting ICMPv4 messages?
3. Give an example of a situation in which a host would never receive a redirection message.
ICMPv4 message