From: Marcelo Ricardo Leitner
> Sent: 20 September 2016 22:19
> sctp_acked() is using 32bit arithmetics on 16bits vars, via TSN_lte()
> macros, which is weird and confusing.
>
> Once the offset to ctsn is calculated, all wrapping is already handled
> and thus to verify the Gap Ack blocks we can just use pure
> less/big-or-equal than checks.
>
> Also, rename gap variable to tsn_offset, so it's more meaningful, as
> it doesn't point to any gap at all.
>
> Even so, I don't think this discrepancy resulted in any practical bug.
I think it might if gab.start/end are greater than 32767
...
> - gap = tsn - ctsn;
> - for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) {
> - if (TSN_lte(ntohs(frags[i].gab.start), gap) &&
> - TSN_lte(gap, ntohs(frags[i].gab.end)))
> + blocks = ntohs(sack->num_gap_ack_blocks);
> + tsn_offset = tsn - ctsn;
> + for (i = 0; i < blocks; ++i) {
> + if (tsn_offset >= ntohs(frags[i].gab.start) &&
> + tsn_offset <= ntohs(frags[i].gab.end))
...
David
