Specify subsequent layers as ICMP payloads and add ICMPv6.Pointer

Moves specification of subsequent layers to the Payload field of the ICMP and
ICMPv6 layers.

Removes the need to manually encode type-specific ICMP or ICMPv6 headers, such
as the "pointer" header of parameter problem messages, in the payload. This is
necessary prework to enable matching of more type-specific headers, such as
"ident" of echo requests.

Fixes a bug where the "reserved" header defined by ICMPv6 RFC 4443 was being
incorrectly encoded by ToBytes. This change fixes the implementation by copying
the payload into Payload, instead of the MessageBody.

PiperOrigin-RevId: 376026420

0 files changed, 0 insertions, 0 deletions