diff options
| -rw-r--r-- | include/net/tcp.h | 15 | ||||
| -rw-r--r-- | net/dccp/ccids/ccid2.c | 8 | ||||
| -rw-r--r-- | net/ipv4/tcp_input.c | 17 |
3 files changed, 19 insertions, 21 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h index df6a2eb..a640221 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -779,6 +779,21 @@ static inline __u32 tcp_current_ssthresh(const struct sock *sk) /* Use define here intentionally to get WARN_ON location shown at the caller */ #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out) +/* + * Convert RFC 3390 larger initial window into an equivalent number of packets. + * + * John Heffner states: + * + * The RFC specifies a window of no more than 4380 bytes + * unless 2*MSS > 4380. Reading the pseudocode in the RFC + * is a bit misleading because they use a clamp at 4380 bytes + * rather than a multiplier in the relevant range. + */ +static inline u32 rfc3390_bytes_to_packets(const u32 smss) +{ + return smss <= 1095 ? 4 : (smss > 1460 ? 2 : 3); +} + extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh); extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst); diff --git a/net/dccp/ccids/ccid2.c b/net/dccp/ccids/ccid2.c index 8c95813..b9c942a 100644 --- a/net/dccp/ccids/ccid2.c +++ b/net/dccp/ccids/ccid2.c @@ -641,12 +641,8 @@ static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk) /* RFC 4341, 5: initialise ssthresh to arbitrarily high (max) value */ hc->tx_ssthresh = ~0U; - /* - * RFC 4341, 5: "The cwnd parameter is initialized to at most four - * packets for new connections, following the rules from [RFC3390]". - * We need to convert the bytes of RFC3390 into the packets of RFC 4341. - */ - hc->tx_cwnd = clamp(4380U / dp->dccps_mss_cache, 2U, 4U); + /* Use larger initial windows (RFC 4341, section 5). */ + hc->tx_cwnd = rfc3390_bytes_to_packets(dp->dccps_mss_cache); /* Make sure that Ack Ratio is enabled and within bounds. */ max_ratio = DIV_ROUND_UP(hc->tx_cwnd, 2); diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index e663b78..1bc87a0 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -805,25 +805,12 @@ void tcp_update_metrics(struct sock *sk) } } -/* Numbers are taken from RFC3390. - * - * John Heffner states: - * - * The RFC specifies a window of no more than 4380 bytes - * unless 2*MSS > 4380. Reading the pseudocode in the RFC - * is a bit misleading because they use a clamp at 4380 bytes - * rather than use a multiplier in the relevant range. - */ __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst) { __u32 cwnd = (dst ? dst_metric(dst, RTAX_INITCWND) : 0); - if (!cwnd) { - if (tp->mss_cache > 1460) - cwnd = 2; - else - cwnd = (tp->mss_cache > 1095) ? 3 : 4; - } + if (!cwnd) + cwnd = rfc3390_bytes_to_packets(tp->mss_cache); return min_t(__u32, cwnd, tp->snd_cwnd_clamp); } |
