[AFS3-std] rxgk key version number of value zero

[Simon Wilkinson]

On 11 Dec 2012, at 20:05, Michael Meffie wrote:

>   The Checksum field allows for an optional packet checksum.  A zero=20=

>   checksum field value means that checksums are not being computed.  =
An
>   Rx security protocol (identified by the security field, described
>   below) may choose to use this field to transport some checksum of =
the
>   packet that is computed and verified by it (for example, rxkad uses=20=

>   this field for a cryptographic header checksum).  Rx itself makes no
>   use of the checksum field.

Technically, this is a "spare" field that rxkad hijacked to use for =
checksums. I don't think there's any particular problem with rxgk =
assigning it a different meaning. One possible consideration is that the =
OpenAFS RX stack notes the presence of non-zero values here, and the =
rx_IsUsingPktCksum() function will return true if it has seen any in the =
life of the connection. However, the only caller of this function in the =
OpenAFS code is rxkad, and I don't think it makes much sense outside of =
rxkad itself.

Cheers,

Simon.