[Nfd-dev] Please review the update of NDN-TLV spec, introducing implicit digest name component

[Alex Afanasyev]

Hi all,

Quick background.  After many discussions, we concluded that it is important to amend current Name TLV definition,  to allow implicit digest component.  After this change, Interest that specify implicit digest, must use implicit digest component at the end of the Name in order for the forwarder/applications to consider it as implicit digest.  This explicit knowledge would allow us to simplify implementation of on-demand implicit digest calculation in NFD (with the old definition, there are several problems that prevented to implement this/significantly complicate implementation logic).

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Please review the change to NDN-TLV spec: http://gerrit.named-data.net/#/c/1289/.  You can either leave comment in gerrit (+1 / -1) or give your feedback in this mailing list.

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The change slightly redefines what NameComponent TLV is:


    Name ::= NAME-TYPE TLV-LENGTH NameComponent*

    NameComponent ::= GenericNameComponent |
                      ImplicitSha256DigestComponent

    GenericNameComponent ::= NAME-COMPONENT-TYPE TLV-LENGTH BYTE*

    ImplicitSha256DigestComponent ::= IMPLICIT-SHA256-DIGEST-COMPONENT-TYPE TLV-LENGTH(=32)
                                        BYTE{32}


- ``GenericNameComponent`` is a generic name component, without any restrictions on the content of the value.

- ``ImplicitSha256DigestComponent`` is an implicit SHA256 digest component and it is required to contain a value of 32 octets.


---
Alex