diff options
| -rw-r--r-- | net/dccp/ccids/ccid3.c | 9 | ||||
| -rw-r--r-- | net/dccp/ccids/lib/tfrc.h | 1 | ||||
| -rw-r--r-- | net/dccp/ccids/lib/tfrc_equation.c | 17 |
3 files changed, 20 insertions, 7 deletions
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c index 4c422fb2189f..206204551f4d 100644 --- a/net/dccp/ccids/ccid3.c +++ b/net/dccp/ccids/ccid3.c @@ -410,10 +410,10 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) /* Update loss event rate (which is scaled by 1e6) */ pinv = opt_recv->ccid3or_loss_event_rate; - if (pinv == ~0U || pinv == 0) /* see RFC 4342, 8.5 */ + if (pinv == 0) hctx->p = 0; - else /* can not exceed 100% */ - hctx->p = scaled_div(1, pinv); + else + hctx->p = tfrc_invert_loss_event_rate(pinv); /* * Update allowed sending rate X as per draft rfc3448bis-00, 4.2/3 @@ -854,8 +854,7 @@ static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len, return -EINVAL; rx_info.tfrcrx_x_recv = hcrx->x_recv; rx_info.tfrcrx_rtt = hcrx->rtt; - rx_info.tfrcrx_p = hcrx->p_inverse == 0 ? ~0U : - scaled_div(1, hcrx->p_inverse); + rx_info.tfrcrx_p = tfrc_invert_loss_event_rate(hcrx->p_inverse); len = sizeof(rx_info); val = &rx_info; break; diff --git a/net/dccp/ccids/lib/tfrc.h b/net/dccp/ccids/lib/tfrc.h index ed9857527acf..bb47146ac7d1 100644 --- a/net/dccp/ccids/lib/tfrc.h +++ b/net/dccp/ccids/lib/tfrc.h @@ -58,6 +58,7 @@ static inline u32 tfrc_ewma(const u32 avg, const u32 newval, const u8 weight) extern u32 tfrc_calc_x(u16 s, u32 R, u32 p); extern u32 tfrc_calc_x_reverse_lookup(u32 fvalue); +extern u32 tfrc_invert_loss_event_rate(u32 loss_event_rate); extern int tfrc_tx_packet_history_init(void); extern void tfrc_tx_packet_history_exit(void); diff --git a/net/dccp/ccids/lib/tfrc_equation.c b/net/dccp/ccids/lib/tfrc_equation.c index 2f20a29cffe4..bc3dc2b2a849 100644 --- a/net/dccp/ccids/lib/tfrc_equation.c +++ b/net/dccp/ccids/lib/tfrc_equation.c @@ -658,7 +658,6 @@ u32 tfrc_calc_x(u16 s, u32 R, u32 p) result = scaled_div(s, R); return scaled_div32(result, f); } - EXPORT_SYMBOL_GPL(tfrc_calc_x); /** @@ -693,5 +692,19 @@ u32 tfrc_calc_x_reverse_lookup(u32 fvalue) index = tfrc_binsearch(fvalue, 0); return (index + 1) * 1000000 / TFRC_CALC_X_ARRSIZE; } - EXPORT_SYMBOL_GPL(tfrc_calc_x_reverse_lookup); + +/** + * tfrc_invert_loss_event_rate - Compute p so that 10^6 corresponds to 100% + * When @loss_event_rate is large, there is a chance that p is truncated to 0. + * To avoid re-entering slow-start in that case, we set p = TFRC_SMALLEST_P > 0. + */ +u32 tfrc_invert_loss_event_rate(u32 loss_event_rate) +{ + if (loss_event_rate == UINT_MAX) /* see RFC 4342, 8.5 */ + return 0; + if (unlikely(loss_event_rate == 0)) /* map 1/0 into 100% */ + return 1000000; + return max_t(u32, scaled_div(1, loss_event_rate), TFRC_SMALLEST_P); +} +EXPORT_SYMBOL_GPL(tfrc_invert_loss_event_rate); |