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Message-Id: <4b813e5bcf8ae5ce1865a1c75e73eb2e5e8d2ac7.1624239422.git.lucien.xin@gmail.com>
Date: Sun, 20 Jun 2021 21:38:40 -0400
From: Xin Long <lucien.xin@...il.com>
To: network dev <netdev@...r.kernel.org>, davem@...emloft.net,
kuba@...nel.org,
Marcelo Ricardo Leitner <marcelo.leitner@...il.com>,
linux-sctp@...r.kernel.org
Subject: [PATCH net-next 05/14] sctp: add the probe timer in transport for PLPMTUD
There are 3 timers described in rfc8899#section-5.1.1:
PROBE_TIMER, PMTU_RAISE_TIMER, CONFIRMATION_TIMER
This patches adds a 'probe_timer' in transport, and it works as either
PROBE_TIMER or PMTU_RAISE_TIMER. At most time, it works as PROBE_TIMER
and expires every a 'probe_interval' time to send the HB probe packet.
When transport pl enters COMPLETE state, it works as PMTU_RAISE_TIMER
and expires in 'probe_interval * 30' time to go back to SEARCH state
and do searching again.
SCTP HB is an acknowledged packet, CONFIRMATION_TIMER is not needed.
The timer will start when transport pl enters BASE state and stop
when it enters DISABLED state.
Signed-off-by: Xin Long <lucien.xin@...il.com>
---
include/net/sctp/command.h | 1 +
include/net/sctp/constants.h | 1 +
include/net/sctp/sctp.h | 9 ++++++++-
include/net/sctp/sm.h | 2 ++
include/net/sctp/structs.h | 4 ++++
net/sctp/debug.c | 1 +
net/sctp/sm_sideeffect.c | 37 ++++++++++++++++++++++++++++++++++++
net/sctp/sm_statefuns.c | 17 +++++++++++++++++
net/sctp/sm_statetable.c | 20 +++++++++++++++++++
net/sctp/transport.c | 18 ++++++++++++++++++
10 files changed, 109 insertions(+), 1 deletion(-)
diff --git a/include/net/sctp/command.h b/include/net/sctp/command.h
index 5e848884ff61..2058fabffbf6 100644
--- a/include/net/sctp/command.h
+++ b/include/net/sctp/command.h
@@ -59,6 +59,7 @@ enum sctp_verb {
SCTP_CMD_HB_TIMERS_START, /* Start the heartbeat timers. */
SCTP_CMD_HB_TIMER_UPDATE, /* Update a heartbeat timers. */
SCTP_CMD_HB_TIMERS_STOP, /* Stop the heartbeat timers. */
+ SCTP_CMD_PROBE_TIMER_UPDATE, /* Update a probe timer. */
SCTP_CMD_TRANSPORT_HB_SENT, /* Reset the status of a transport. */
SCTP_CMD_TRANSPORT_IDLE, /* Do manipulations on idle transport */
SCTP_CMD_TRANSPORT_ON, /* Mark the transport as active. */
diff --git a/include/net/sctp/constants.h b/include/net/sctp/constants.h
index 85f6a105c59d..265fffa33dad 100644
--- a/include/net/sctp/constants.h
+++ b/include/net/sctp/constants.h
@@ -77,6 +77,7 @@ enum sctp_event_timeout {
SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD,
SCTP_EVENT_TIMEOUT_HEARTBEAT,
SCTP_EVENT_TIMEOUT_RECONF,
+ SCTP_EVENT_TIMEOUT_PROBE,
SCTP_EVENT_TIMEOUT_SACK,
SCTP_EVENT_TIMEOUT_AUTOCLOSE,
};
diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index 08347d3f004f..f7e083602c10 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -635,10 +635,14 @@ static inline void sctp_transport_pl_reset(struct sctp_transport *t)
t->pl.state = SCTP_PL_BASE;
t->pl.pmtu = SCTP_BASE_PLPMTU;
t->pl.probe_size = SCTP_BASE_PLPMTU;
+ sctp_transport_reset_probe_timer(t);
}
} else {
- if (t->pl.state != SCTP_PL_DISABLED)
+ if (t->pl.state != SCTP_PL_DISABLED) {
+ if (del_timer(&t->probe_timer))
+ sctp_transport_put(t);
t->pl.state = SCTP_PL_DISABLED;
+ }
}
}
@@ -647,6 +651,9 @@ static inline void sctp_transport_pl_update(struct sctp_transport *t)
if (t->pl.state == SCTP_PL_DISABLED)
return;
+ if (del_timer(&t->probe_timer))
+ sctp_transport_put(t);
+
t->pl.state = SCTP_PL_BASE;
t->pl.pmtu = SCTP_BASE_PLPMTU;
t->pl.probe_size = SCTP_BASE_PLPMTU;
diff --git a/include/net/sctp/sm.h b/include/net/sctp/sm.h
index 09c59154634d..45542e2bac93 100644
--- a/include/net/sctp/sm.h
+++ b/include/net/sctp/sm.h
@@ -151,6 +151,7 @@ sctp_state_fn_t sctp_sf_cookie_wait_icmp_abort;
/* Prototypes for timeout event state functions. */
sctp_state_fn_t sctp_sf_do_6_3_3_rtx;
sctp_state_fn_t sctp_sf_send_reconf;
+sctp_state_fn_t sctp_sf_send_probe;
sctp_state_fn_t sctp_sf_do_6_2_sack;
sctp_state_fn_t sctp_sf_autoclose_timer_expire;
@@ -311,6 +312,7 @@ int sctp_do_sm(struct net *net, enum sctp_event_type event_type,
void sctp_generate_t3_rtx_event(struct timer_list *t);
void sctp_generate_heartbeat_event(struct timer_list *t);
void sctp_generate_reconf_event(struct timer_list *t);
+void sctp_generate_probe_event(struct timer_list *t);
void sctp_generate_proto_unreach_event(struct timer_list *t);
void sctp_ootb_pkt_free(struct sctp_packet *packet);
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 85d3566c2227..a3772f8ee7f6 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -936,6 +936,9 @@ struct sctp_transport {
/* Timer to handler reconf chunk rtx */
struct timer_list reconf_timer;
+ /* Timer to send a probe HB packet for PLPMTUD */
+ struct timer_list probe_timer;
+
/* Since we're using per-destination retransmission timers
* (see above), we're also using per-destination "transmitted"
* queues. This probably ought to be a private struct
@@ -1003,6 +1006,7 @@ void sctp_transport_free(struct sctp_transport *);
void sctp_transport_reset_t3_rtx(struct sctp_transport *);
void sctp_transport_reset_hb_timer(struct sctp_transport *);
void sctp_transport_reset_reconf_timer(struct sctp_transport *transport);
+void sctp_transport_reset_probe_timer(struct sctp_transport *transport);
int sctp_transport_hold(struct sctp_transport *);
void sctp_transport_put(struct sctp_transport *);
void sctp_transport_update_rto(struct sctp_transport *, __u32);
diff --git a/net/sctp/debug.c b/net/sctp/debug.c
index c4d9c7feffb9..ccd773e4c371 100644
--- a/net/sctp/debug.c
+++ b/net/sctp/debug.c
@@ -154,6 +154,7 @@ static const char *const sctp_timer_tbl[] = {
"TIMEOUT_T5_SHUTDOWN_GUARD",
"TIMEOUT_HEARTBEAT",
"TIMEOUT_RECONF",
+ "TIMEOUT_PROBE",
"TIMEOUT_SACK",
"TIMEOUT_AUTOCLOSE",
};
diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index ce15d590a615..b3815b568e8e 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -471,6 +471,38 @@ void sctp_generate_reconf_event(struct timer_list *t)
sctp_transport_put(transport);
}
+/* Handle the timeout of the probe timer. */
+void sctp_generate_probe_event(struct timer_list *t)
+{
+ struct sctp_transport *transport = from_timer(transport, t, probe_timer);
+ struct sctp_association *asoc = transport->asoc;
+ struct sock *sk = asoc->base.sk;
+ struct net *net = sock_net(sk);
+ int error = 0;
+
+ bh_lock_sock(sk);
+ if (sock_owned_by_user(sk)) {
+ pr_debug("%s: sock is busy\n", __func__);
+
+ /* Try again later. */
+ if (!mod_timer(&transport->probe_timer, jiffies + (HZ / 20)))
+ sctp_transport_hold(transport);
+ goto out_unlock;
+ }
+
+ error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT,
+ SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_PROBE),
+ asoc->state, asoc->ep, asoc,
+ transport, GFP_ATOMIC);
+
+ if (error)
+ sk->sk_err = -error;
+
+out_unlock:
+ bh_unlock_sock(sk);
+ sctp_transport_put(transport);
+}
+
/* Inject a SACK Timeout event into the state machine. */
static void sctp_generate_sack_event(struct timer_list *t)
{
@@ -1641,6 +1673,11 @@ static int sctp_cmd_interpreter(enum sctp_event_type event_type,
sctp_cmd_hb_timers_stop(commands, asoc);
break;
+ case SCTP_CMD_PROBE_TIMER_UPDATE:
+ t = cmd->obj.transport;
+ sctp_transport_reset_probe_timer(t);
+ break;
+
case SCTP_CMD_REPORT_ERROR:
error = cmd->obj.error;
break;
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 4f30388a0dd0..3b99eda50618 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -1095,6 +1095,23 @@ enum sctp_disposition sctp_sf_send_reconf(struct net *net,
return SCTP_DISPOSITION_CONSUME;
}
+/* send hb chunk with padding for PLPMUTD. */
+enum sctp_disposition sctp_sf_send_probe(struct net *net,
+ const struct sctp_endpoint *ep,
+ const struct sctp_association *asoc,
+ const union sctp_subtype type,
+ void *arg,
+ struct sctp_cmd_seq *commands)
+{
+ struct sctp_transport *transport = (struct sctp_transport *)arg;
+
+ /* The actual handling will be performed here in a later patch. */
+ sctp_add_cmd_sf(commands, SCTP_CMD_PROBE_TIMER_UPDATE,
+ SCTP_TRANSPORT(transport));
+
+ return SCTP_DISPOSITION_CONSUME;
+}
+
/*
* Process an heartbeat request.
*
diff --git a/net/sctp/sm_statetable.c b/net/sctp/sm_statetable.c
index c82c4233ec6b..1816a4410b2b 100644
--- a/net/sctp/sm_statetable.c
+++ b/net/sctp/sm_statetable.c
@@ -967,6 +967,25 @@ other_event_table[SCTP_NUM_OTHER_TYPES][SCTP_STATE_NUM_STATES] = {
TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
}
+#define TYPE_SCTP_EVENT_TIMEOUT_PROBE { \
+ /* SCTP_STATE_CLOSED */ \
+ TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
+ /* SCTP_STATE_COOKIE_WAIT */ \
+ TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
+ /* SCTP_STATE_COOKIE_ECHOED */ \
+ TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
+ /* SCTP_STATE_ESTABLISHED */ \
+ TYPE_SCTP_FUNC(sctp_sf_send_probe), \
+ /* SCTP_STATE_SHUTDOWN_PENDING */ \
+ TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
+ /* SCTP_STATE_SHUTDOWN_SENT */ \
+ TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
+ /* SCTP_STATE_SHUTDOWN_RECEIVED */ \
+ TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
+ /* SCTP_STATE_SHUTDOWN_ACK_SENT */ \
+ TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
+}
+
static const struct sctp_sm_table_entry
timeout_event_table[SCTP_NUM_TIMEOUT_TYPES][SCTP_STATE_NUM_STATES] = {
TYPE_SCTP_EVENT_TIMEOUT_NONE,
@@ -978,6 +997,7 @@ timeout_event_table[SCTP_NUM_TIMEOUT_TYPES][SCTP_STATE_NUM_STATES] = {
TYPE_SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD,
TYPE_SCTP_EVENT_TIMEOUT_HEARTBEAT,
TYPE_SCTP_EVENT_TIMEOUT_RECONF,
+ TYPE_SCTP_EVENT_TIMEOUT_PROBE,
TYPE_SCTP_EVENT_TIMEOUT_SACK,
TYPE_SCTP_EVENT_TIMEOUT_AUTOCLOSE,
};
diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index bf0ac467e757..ca3343c2c80e 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -75,6 +75,7 @@ static struct sctp_transport *sctp_transport_init(struct net *net,
timer_setup(&peer->T3_rtx_timer, sctp_generate_t3_rtx_event, 0);
timer_setup(&peer->hb_timer, sctp_generate_heartbeat_event, 0);
timer_setup(&peer->reconf_timer, sctp_generate_reconf_event, 0);
+ timer_setup(&peer->probe_timer, sctp_generate_probe_event, 0);
timer_setup(&peer->proto_unreach_timer,
sctp_generate_proto_unreach_event, 0);
@@ -131,6 +132,9 @@ void sctp_transport_free(struct sctp_transport *transport)
if (del_timer(&transport->reconf_timer))
sctp_transport_put(transport);
+ if (del_timer(&transport->probe_timer))
+ sctp_transport_put(transport);
+
/* Delete the ICMP proto unreachable timer if it's active. */
if (del_timer(&transport->proto_unreach_timer))
sctp_transport_put(transport);
@@ -207,6 +211,20 @@ void sctp_transport_reset_reconf_timer(struct sctp_transport *transport)
sctp_transport_hold(transport);
}
+void sctp_transport_reset_probe_timer(struct sctp_transport *transport)
+{
+ int scale = 1;
+
+ if (timer_pending(&transport->probe_timer))
+ return;
+ if (transport->pl.state == SCTP_PL_COMPLETE &&
+ transport->pl.probe_count == 1)
+ scale = 30; /* works as PMTU_RAISE_TIMER */
+ if (!mod_timer(&transport->probe_timer,
+ jiffies + transport->probe_interval * scale))
+ sctp_transport_hold(transport);
+}
+
/* This transport has been assigned to an association.
* Initialize fields from the association or from the sock itself.
* Register the reference count in the association.
--
2.27.0
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