diff options
| -rw-r--r-- | net/dccp/ccids/Kconfig | 20 | ||||
| -rw-r--r-- | net/dccp/ccids/ccid3.c | 27 |
2 files changed, 35 insertions, 12 deletions
diff --git a/net/dccp/ccids/Kconfig b/net/dccp/ccids/Kconfig index dc973abe03b4..fb168be2cb43 100644 --- a/net/dccp/ccids/Kconfig +++ b/net/dccp/ccids/Kconfig @@ -74,6 +74,26 @@ config IP_DCCP_CCID3_DEBUG If in doubt, say N. +choice + prompt "Select method for measuring the packet size s" + default IP_DCCP_CCID3_MEASURE_S_AS_MPS + +config IP_DCCP_CCID3_MEASURE_S_AS_MPS + bool "Always use MPS in place of s" + ---help--- + This use is recommended as it is consistent with the initialisation + of X and suggested when s varies (rfc3448bis, (1) in section 4.1). +config IP_DCCP_CCID3_MEASURE_S_AS_AVG + bool "Use moving average" + ---help--- + An alternative way of tracking s, also supported by rfc3448bis. + This used to be the default for CCID-3 in previous kernels. +config IP_DCCP_CCID3_MEASURE_S_AS_MAX + bool "Track the maximum payload length" + ---help--- + An experimental method based on tracking the maximum packet size. +endchoice + config IP_DCCP_CCID3_RTO int "Use higher bound for nofeedback timer" default 100 diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c index d654264c5108..d77d3e664b7e 100644 --- a/net/dccp/ccids/ccid3.c +++ b/net/dccp/ccids/ccid3.c @@ -136,17 +136,18 @@ static void ccid3_hc_tx_update_x(struct sock *sk, ktime_t *stamp) } /* - * Track the mean packet size `s' (cf. RFC 4342, 5.3 and RFC 3448, 4.1) - * @len: DCCP packet payload size in bytes + * ccid3_hc_tx_measure_packet_size - Measuring the packet size `s' (sec 4.1) + * @new_len: DCCP payload size in bytes (not used by all methods) */ -static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hctx, int len) +static u32 ccid3_hc_tx_measure_packet_size(struct sock *sk, const u16 new_len) { - const u16 old_s = hctx->s; - - hctx->s = tfrc_ewma(hctx->s, len, 9); - - if (hctx->s != old_s) - ccid3_update_send_interval(hctx); +#if defined(CONFIG_IP_DCCP_CCID3_MEASURE_S_AS_AVG) + return tfrc_ewma(ccid3_hc_tx_sk(sk)->s, new_len, 9); +#elif defined(CONFIG_IP_DCCP_CCID3_MEASURE_S_AS_MAX) + return max(ccid3_hc_tx_sk(sk)->s, new_len); +#else /* CONFIG_IP_DCCP_CCID3_MEASURE_S_AS_MPS */ + return dccp_sk(sk)->dccps_mss_cache; +#endif } /* @@ -271,8 +272,6 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) /* Set t_0 for initial packet */ hctx->t_nom = now; - hctx->s = skb->len; - /* * Use initial RTT sample when available: recommended by erratum * to RFC 4342. This implements the initialisation procedure of @@ -294,6 +293,9 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) hctx->x = dp->dccps_mss_cache; hctx->x <<= 6; } + + /* Compute t_ipi = s / X */ + hctx->s = ccid3_hc_tx_measure_packet_size(sk, skb->len); ccid3_update_send_interval(hctx); } else { @@ -326,7 +328,8 @@ static void ccid3_hc_tx_packet_sent(struct sock *sk, unsigned int len) { struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); - ccid3_hc_tx_update_s(hctx, len); + /* Changes to s will become effective the next time X is computed */ + hctx->s = ccid3_hc_tx_measure_packet_size(sk, len); if (tfrc_tx_hist_add(&hctx->hist, dccp_sk(sk)->dccps_gss)) DCCP_CRIT("packet history - out of memory!"); |