diff options
Diffstat (limited to 'net/dccp/ccids/ccid2.c')
| -rw-r--r-- | net/dccp/ccids/ccid2.c | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/net/dccp/ccids/ccid2.c b/net/dccp/ccids/ccid2.c index 9c5b6c73f7c9..a901202ada64 100644 --- a/net/dccp/ccids/ccid2.c +++ b/net/dccp/ccids/ccid2.c @@ -224,8 +224,6 @@ static void ccid2_hc_tx_rto_expire(unsigned long data) hctx->ccid2hctx_sent = 0; /* clear ack ratio state. */ - hctx->ccid2hctx_arsent = 0; - hctx->ccid2hctx_ackloss = 0; hctx->ccid2hctx_rpseq = 0; hctx->ccid2hctx_rpdupack = -1; ccid2_change_l_ack_ratio(sk, 1); @@ -289,6 +287,26 @@ static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len) hctx->ccid2hctx_sent++; + /* + * FIXME: The code below is broken and the variables have been removed + * from the socket struct. The `ackloss' variable was always set to 0, + * and with arsent there are several problems: + * (i) it doesn't just count the number of Acks, but all sent packets; + * (ii) it is expressed in # of packets, not # of windows, so the + * comparison below uses the wrong formula: Appendix A of RFC 4341 + * comes up with the number K = cwnd / (R^2 - R) of consecutive windows + * of data with no lost or marked Ack packets. If arsent were the # of + * consecutive Acks received without loss, then Ack Ratio needs to be + * decreased by 1 when + * arsent >= K * cwnd / R = cwnd^2 / (R^3 - R^2) + * where cwnd / R is the number of Acks received per window of data + * (cf. RFC 4341, App. A). The problems are that + * - arsent counts other packets as well; + * - the comparison uses a formula different from RFC 4341; + * - computing a cubic/quadratic equation each time is too complicated. + * Hence a different algorithm is needed. + */ +#if 0 /* Ack Ratio. Need to maintain a concept of how many windows we sent */ hctx->ccid2hctx_arsent++; /* We had an ack loss in this window... */ @@ -316,6 +334,7 @@ static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len) hctx->ccid2hctx_arsent = 0; /* or maybe set it to cwnd*/ } } +#endif /* setup RTO timer */ if (!timer_pending(&hctx->ccid2hctx_rtotimer)) |