On 10/3/07, Gerrit Renker <gerrit@xxxxxxxxxxxxxx> wrote: > ------------------------------> Patch v2 <----------------------------------------- > [DCCP]: Resolve dependencies of features on choice of CCID > > This provides a missing link in the code chain, as several features implicitly > depend and/or rely on the choice of CCID. Most notably, this is the Send Ack Vector > feature, but the patch also takes care of Ack Ratio and Send Loss Event Rate. > > For Send Ack Vector, the situation is as follows: > * since CCID2 mandates the use of Ack Vectors, there is no point in allowing endpoints > which use CCID2 to disable Send Ack Vector features on the corresponding half-connection; > > * a peer with a TX CCID of CCID2 will always expect Ack Vectors, and a peer with a RX CCID > of CCID2 must always send Ack Vectors (RFC 4341, sec. 4); > > * for all other CCIDs, the use of (Send) Ack Vector is optional and thus negotiable. However, > this implies that the code negotiating the use of Ack Vectors also supports it (i.e. is > able to supply and to either parse or ignore received Ack Vectors). Since this is not the > case (CCID3 has no Ack Vector support), the use of Ack Vectors is here disabled, with a > corresponding comment in the source code. > > An analogous consideration arises for the Send Loss Event Rate feature, since the CCID3 > implementation does not support the loss interval options of RFC 4342. To make such use explicit, > corresponding feature-negotiation options are inserted which signal the use of the loss event > rate option, as it is used by the CCID3 code. > > Lastly, the values of the Ack Ratio feature are matched to the choice of CCID. > > The patch implements this as a function which is called after the user has made all other > registrations for changing default values of features. > > The table is variable-length, the reserved (and hence for feature-negotiation invalid, confirmed > by considering section 19.4 of RFC 4340) feature number of 0 is used to mark the end of the table. > > Signed-off-by: Gerrit Renker <gerrit@xxxxxxxxxxxxxx> Acked-by: Ian McDonald <ian.mcdonald@xxxxxxxxxxx> (I have seen Arnaldo's/your later correspondence and happy enough that you'll resolve that) -- Web1: http://wand.net.nz/~iam4/ Web2: http://www.jandi.co.nz Blog: http://iansblog.jandi.co.nz - To unsubscribe from this list: send the line "unsubscribe dccp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
