diff options
| author | Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> | 2017-06-23 19:59:35 -0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-06-25 14:43:53 -0400 |
| commit | 4ccbd0b0b9b8b09d87c7e7b0f868eda2bed03189 (patch) | |
| tree | eada21acf5a392e12a7a42fd5ec0fb64a6645780 /net/sctp | |
| parent | e56f777af82ebbdf8302164b040128d890f100d8 (diff) | |
sctp: adjust cwnd increase in Congestion Avoidance phase
RFC4960 Errata 3.26 identified that at the same time RFC4960 states that
cwnd should never grow more than 1*MTU per RTT, Section 7.2.2 was
underspecified and as described could allow increasing cwnd more than
that.
This patch updates it so partial_bytes_acked is maxed to cwnd if
flight_size doesn't reach cwnd, protecting it from such case.
See-also: https://tools.ietf.org/html/draft-ietf-tsvwg-rfc4960-errata-01#section-3.26
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sctp')
| -rw-r--r-- | net/sctp/transport.c | 26 |
1 files changed, 18 insertions, 8 deletions
diff --git a/net/sctp/transport.c b/net/sctp/transport.c index 9d3589451a96..e3ebf04ddbd0 100644 --- a/net/sctp/transport.c +++ b/net/sctp/transport.c @@ -405,13 +405,6 @@ void sctp_transport_raise_cwnd(struct sctp_transport *transport, TSN_lte(asoc->fast_recovery_exit, sack_ctsn)) asoc->fast_recovery = 0; - /* The appropriate cwnd increase algorithm is performed if, and only - * if the congestion window is being fully utilized. - * Note that RFC4960 Errata 3.22 removed the other condition. - */ - if (flight_size < cwnd) - return; - ssthresh = transport->ssthresh; pba = transport->partial_bytes_acked; pmtu = transport->asoc->pathmtu; @@ -434,6 +427,14 @@ void sctp_transport_raise_cwnd(struct sctp_transport *transport, if (asoc->fast_recovery) return; + /* The appropriate cwnd increase algorithm is performed + * if, and only if the congestion window is being fully + * utilized. Note that RFC4960 Errata 3.22 removed the + * other condition on ctsn moving. + */ + if (flight_size < cwnd) + return; + if (bytes_acked > pmtu) cwnd += pmtu; else @@ -451,6 +452,13 @@ void sctp_transport_raise_cwnd(struct sctp_transport *transport, * acknowledged by the new Cumulative TSN Ack and by Gap * Ack Blocks. (updated by RFC4960 Errata 3.22) * + * When partial_bytes_acked is greater than cwnd and + * before the arrival of the SACK the sender had less + * bytes of data outstanding than cwnd (i.e., before + * arrival of the SACK, flightsize was less than cwnd), + * reset partial_bytes_acked to cwnd. (RFC 4960 Errata + * 3.26) + * * When partial_bytes_acked is equal to or greater than * cwnd and before the arrival of the SACK the sender * had cwnd or more bytes of data outstanding (i.e., @@ -460,7 +468,9 @@ void sctp_transport_raise_cwnd(struct sctp_transport *transport, * increased by MTU. (RFC 4960 Errata 3.12) */ pba += bytes_acked; - if (pba >= cwnd) { + if (pba > cwnd && flight_size < cwnd) + pba = cwnd; + if (pba >= cwnd && flight_size >= cwnd) { pba = pba - cwnd; cwnd += pmtu; } |