On 9/26/07, Gerrit Renker <gerrit@xxxxxxxxxxxxxx> wrote: > [DCCP]: Add (missing) option parsing to request_sock processing > > This adds option-parsing code to processing of Acks in the listening state > on request_socks on the server, serving two purposes > (i) resolves a FIXME (removed); > (ii) paves the way for feature-negotiation during connection-setup. > > There is an intended subtlety here with regard to dccp_check_req: > > Parsing options happens only after testing whether the received packet is > a retransmitted Request. Otherwise, if the Request contained (a possibly > large number of) feature-negotiation options, recomputing state would have to > happen each time a retransmitted Request arrives, which opens the door to an > easy DoS attack. Since in a genuine retransmission the options should not be > different from the original, reusing the already computed state seems better. > > The other point is - if there are timestamp options on the Request, they will > not be answered; which means that in the presence of retransmission (likely > due to loss and/or other problems), the use of Request/Response RTT sampling > is suspended, so that startup problems here do not propagate. > > Signed-off-by: Gerrit Renker <gerrit@xxxxxxxxxxxxxx> Signed-off-by: Ian McDonald <ian.mcdonald@xxxxxxxxxxx> -- 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
