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[66.187.233.206]) by smtp.gmail.com with ESMTPSA id x12sm4387940qtr.22.2021.06.20.18.38.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 20 Jun 2021 18:38:58 -0700 (PDT) From: Xin Long To: network dev , davem@davemloft.net, kuba@kernel.org, Marcelo Ricardo Leitner , linux-sctp@vger.kernel.org Subject: [PATCH net-next 07/14] sctp: do state transition when PROBE_COUNT == MAX_PROBES on HB send path Date: Sun, 20 Jun 2021 21:38:42 -0400 Message-Id: <4195d17261dd4967de4ae4a19e442a11ead84cdf.1624239422.git.lucien.xin@gmail.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-sctp@vger.kernel.org The state transition is described in rfc8899#section-5.2, PROBE_COUNT == MAX_PROBES means the probe fails for MAX times, and the state transition includes: - Base -> Error, occurs when BASE_PLPMTU Confirmation Fails, pl.pmtu is set to SCTP_MIN_PLPMTU, probe_size is still SCTP_BASE_PLPMTU; - Search -> Base, occurs when Black Hole Detected, pl.pmtu is set to SCTP_BASE_PLPMTU, probe_size is set back to SCTP_BASE_PLPMTU; - Search Complete -> Base, occurs when Black Hole Detected pl.pmtu is set to SCTP_BASE_PLPMTU, probe_size is set back to SCTP_BASE_PLPMTU; Note a black hole is encountered when a sender is unaware that packets are not being delivered to the destination endpoint. So it includes the probe failures with equal probe_size to pl.pmtu, and definitely not include that with greater probe_size than pl.pmtu. The later one is the normal probe failure where probe_size should decrease back to pl.pmtu and pl.probe_high is set. pl.probe_high would be used on HB ACK recv path in the next patch. Signed-off-by: Xin Long --- include/net/sctp/structs.h | 1 + net/sctp/sm_statefuns.c | 2 ++ net/sctp/transport.c | 44 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 47 insertions(+) diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h index f7b056f5af37..31165720b28a 100644 --- a/include/net/sctp/structs.h +++ b/include/net/sctp/structs.h @@ -1023,6 +1023,7 @@ bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu); void sctp_transport_immediate_rtx(struct sctp_transport *); void sctp_transport_dst_release(struct sctp_transport *t); void sctp_transport_dst_confirm(struct sctp_transport *t); +void sctp_transport_pl_send(struct sctp_transport *t); /* This is the structure we use to queue packets as they come into diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c index 8edb9186112a..66c409e5b47c 100644 --- a/net/sctp/sm_statefuns.c +++ b/net/sctp/sm_statefuns.c @@ -1109,6 +1109,8 @@ enum sctp_disposition sctp_sf_send_probe(struct net *net, if (!sctp_transport_pl_enabled(transport)) return SCTP_DISPOSITION_CONSUME; + sctp_transport_pl_send(transport); + reply = sctp_make_heartbeat(asoc, transport, transport->pl.probe_size); if (!reply) return SCTP_DISPOSITION_NOMEM; diff --git a/net/sctp/transport.c b/net/sctp/transport.c index ca3343c2c80e..99620d86e317 100644 --- a/net/sctp/transport.c +++ b/net/sctp/transport.c @@ -261,6 +261,50 @@ void sctp_transport_pmtu(struct sctp_transport *transport, struct sock *sk) transport->pathmtu = SCTP_DEFAULT_MAXSEGMENT; } +void sctp_transport_pl_send(struct sctp_transport *t) +{ + pr_debug("%s: PLPMTUD: transport: %p, state: %d, pmtu: %d, size: %d, high: %d\n", + __func__, t, t->pl.state, t->pl.pmtu, t->pl.probe_size, t->pl.probe_high); + + if (t->pl.probe_count < SCTP_MAX_PROBES) { + t->pl.probe_count++; + return; + } + + if (t->pl.state == SCTP_PL_BASE) { + if (t->pl.probe_size == SCTP_BASE_PLPMTU) { /* BASE_PLPMTU Confirmation Failed */ + t->pl.state = SCTP_PL_ERROR; /* Base -> Error */ + + t->pl.pmtu = SCTP_MIN_PLPMTU; + t->pathmtu = t->pl.pmtu + sctp_transport_pl_hlen(t); + sctp_assoc_sync_pmtu(t->asoc); + } + } else if (t->pl.state == SCTP_PL_SEARCH) { + if (t->pl.pmtu == t->pl.probe_size) { /* Black Hole Detected */ + t->pl.state = SCTP_PL_BASE; /* Search -> Base */ + t->pl.probe_size = SCTP_BASE_PLPMTU; + t->pl.probe_high = 0; + + t->pl.pmtu = SCTP_BASE_PLPMTU; + t->pathmtu = t->pl.pmtu + sctp_transport_pl_hlen(t); + sctp_assoc_sync_pmtu(t->asoc); + } else { /* Normal probe failure. */ + t->pl.probe_high = t->pl.probe_size; + t->pl.probe_size = t->pl.pmtu; + } + } else if (t->pl.state == SCTP_PL_COMPLETE) { + if (t->pl.pmtu == t->pl.probe_size) { /* Black Hole Detected */ + t->pl.state = SCTP_PL_BASE; /* Search Complete -> Base */ + t->pl.probe_size = SCTP_BASE_PLPMTU; + + t->pl.pmtu = SCTP_BASE_PLPMTU; + t->pathmtu = t->pl.pmtu + sctp_transport_pl_hlen(t); + sctp_assoc_sync_pmtu(t->asoc); + } + } + t->pl.probe_count = 1; +} + bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu) { struct dst_entry *dst = sctp_transport_dst_check(t); -- 2.27.0