Re: [Sidrops] WGLC = draft-ietf-sidrops-aspa-verification - ENDS 03/22/2023 (Mar 22 2023)

[Job Snijders <[e-mail]>]

On Fri, Apr 28, 2023 at 09:56:07AM +0200, Martin Hoffmann wrote:
> > I've added an Appendix to the aspa-profile internet-draft showcasing
> > various eContent payloads and how they transform into RTR PDUs.
> > 
> > I also explicitly noted that a single eContent payload always
> > results in two RTR PDUs, and how multiple eContents payloads for the
> > same Customer ASID also result in exactly two RTR ASPA PDUs.
> 
> That is very helpful, indeed. Thanks!
> 
> Do you think it might be possible to somehow also show the decoded
> ASPA eContent content in the first column to make it easier to spot
> what is going one? I suspect that when an implementation converts from
> object payload to RTR payload, they longs since moved past the encoded
> formats.

I couldn't make that fit well enough with the way xml2rfc generates
tables. I was also concerned about loss of information if these
encodings are expressed in high level language. Of course a canonical
way of representing DER in human-readable format would be XER, but
that's very verbose. By providing the DER-encoded payload, my hope is
that potential for ambiguity is removed.

If people need help encoding/decoding ASN.1/DER/HEX/PEM always feel free
to ping me offlist.

Kind regards,

Job

ps. For the benefit of the group, the Base64-encoded blobs can be
decoded using openssl's asn1parse. First find the offset of the ASPA:

    $ cat << EOF | base64 -d | openssl asn1parse -inform DER
    > MDQGCyqGSIb3DQEJEAEx
    > oCUEIzAhAgMA/mMwGjAL
    > AgUA+lbqAQQCAAEwCwIF
    > APpW6gIEAgAC
    > EOF
        0:d=0  hl=2 l=  52 cons: SEQUENCE
        2:d=1  hl=2 l=  11 prim: OBJECT            :id-ct-ASPA
       15:d=1  hl=2 l=  37 cons: cont [ 0 ]
       17:d=2  hl=2 l=  35 prim: OCTET STRING      [HEX DUMP]:3021020300FE63301A300B020500FA56EA0104020001300B020500FA56EA0204020002

Then decode the ASPA at byte 17 itself:

    $ cat << EOF | base64 -d | openssl asn1parse -i -inform DER -strparse 17
    > MDQGCyqGSIb3DQEJEAEx
    > oCUEIzAhAgMA/mMwGjAL
    > AgUA+lbqAQQCAAEwCwIF
    > APpW6gIEAgAC
    > EOF
        0:d=0  hl=2 l=  33 cons: SEQUENCE
        2:d=1  hl=2 l=   3 prim:  INTEGER           :FE63
        7:d=1  hl=2 l=  26 cons:  SEQUENCE
        9:d=2  hl=2 l=  11 cons:   SEQUENCE
       11:d=3  hl=2 l=   5 prim:    INTEGER           :FA56EA01
       18:d=3  hl=2 l=   2 prim:    OCTET STRING      [HEX DUMP]:0001
       22:d=2  hl=2 l=  11 cons:   SEQUENCE
       24:d=3  hl=2 l=   5 prim:    INTEGER           :FA56EA02
       31:d=3  hl=2 l=   2 prim:    OCTET STRING      [HEX DUMP]:0002