1 files changed, 193 insertions, 51 deletions

diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index 033696e6f74f..0c56d9673cc1 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /* SCTP kernel implementation
  * Copyright (c) 1999-2000 Cisco, Inc.
  * Copyright (c) 1999-2001 Motorola, Inc.
@@ -7,26 +8,10 @@
  *
  * This file is part of the SCTP kernel implementation
  *
- * This module provides the abstraction for an SCTP tranport representing
+ * This module provides the abstraction for an SCTP transport representing
  * a remote transport address.  For local transport addresses, we just use
  * union sctp_addr.
  *
- * This SCTP implementation is free software;
- * you can redistribute it and/or modify it under the terms of
- * the GNU General Public License as published by
- * the Free Software Foundation; either version 2, or (at your option)
- * any later version.
- *
- * This SCTP implementation is distributed in the hope that it
- * will be useful, but WITHOUT ANY WARRANTY; without even the implied
- *                 ************************
- * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
- * See the GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with GNU CC; see the file COPYING.  If not, see
- * <http://www.gnu.org/licenses/>.
- *
  * Please send any bug reports or fixes you make to the
  * email address(es):
  *    lksctp developers <linux-sctp@vger.kernel.org>
@@ -52,14 +37,14 @@
 /* 1st Level Abstractions.  */
 
 /* Initialize a new transport from provided memory.  */
-static struct sctp_transport *sctp_transport_init(struct net *net,
-						  struct sctp_transport *peer,
-						  const union sctp_addr *addr,
-						  gfp_t gfp)
+static void sctp_transport_init(struct net *net,
+				struct sctp_transport *peer,
+				const union sctp_addr *addr,
+				gfp_t gfp)
 {
 	/* Copy in the address.  */
-	peer->ipaddr = *addr;
 	peer->af_specific = sctp_get_af_specific(addr->sa.sa_family);
+	memcpy(&peer->ipaddr, addr, peer->af_specific->sockaddr_len);
 	memset(&peer->saddr, 0, sizeof(union sctp_addr));
 
 	peer->sack_generation = 0;
@@ -90,6 +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);
 
@@ -97,8 +83,6 @@ static struct sctp_transport *sctp_transport_init(struct net *net,
 	get_random_bytes(&peer->hb_nonce, sizeof(peer->hb_nonce));
 
 	refcount_set(&peer->refcnt, 1);
-
-	return peer;
 }
 
 /* Allocate and initialize a new transport.  */
@@ -110,20 +94,13 @@ struct sctp_transport *sctp_transport_new(struct net *net,
 
 	transport = kzalloc(sizeof(*transport), gfp);
 	if (!transport)
-		goto fail;
+		return NULL;
 
-	if (!sctp_transport_init(net, transport, addr, gfp))
-		goto fail_init;
+	sctp_transport_init(net, transport, addr, gfp);
 
 	SCTP_DBG_OBJCNT_INC(transport);
 
 	return transport;
-
-fail_init:
-	kfree(transport);
-
-fail:
-	return NULL;
 }
 
 /* This transport is no longer needed.  Free up if possible, or
@@ -131,24 +108,29 @@ fail:
  */
 void sctp_transport_free(struct sctp_transport *transport)
 {
+	transport->dead = 1;
+
 	/* Try to delete the heartbeat timer.  */
-	if (del_timer(&transport->hb_timer))
+	if (timer_delete(&transport->hb_timer))
 		sctp_transport_put(transport);
 
 	/* Delete the T3_rtx timer if it's active.
 	 * There is no point in not doing this now and letting
 	 * structure hang around in memory since we know
-	 * the tranport is going away.
+	 * the transport is going away.
 	 */
-	if (del_timer(&transport->T3_rtx_timer))
+	if (timer_delete(&transport->T3_rtx_timer))
+		sctp_transport_put(transport);
+
+	if (timer_delete(&transport->reconf_timer))
 		sctp_transport_put(transport);
 
-	if (del_timer(&transport->reconf_timer))
+	if (timer_delete(&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_association_put(transport->asoc);
+	if (timer_delete(&transport->proto_unreach_timer))
+		sctp_transport_put(transport);
 
 	sctp_transport_put(transport);
 }
@@ -207,9 +189,8 @@ void sctp_transport_reset_hb_timer(struct sctp_transport *transport)
 
 	/* When a data chunk is sent, reset the heartbeat interval.  */
 	expires = jiffies + sctp_transport_timeout(transport);
-	if (time_before(transport->hb_timer.expires, expires) &&
-	    !mod_timer(&transport->hb_timer,
-		       expires + prandom_u32_max(transport->rto)))
+	if (!mod_timer(&transport->hb_timer,
+		       expires + get_random_u32_below(transport->rto)))
 		sctp_transport_hold(transport);
 }
 
@@ -221,6 +202,20 @@ void sctp_transport_reset_reconf_timer(struct sctp_transport *transport)
 			sctp_transport_hold(transport);
 }
 
+void sctp_transport_reset_probe_timer(struct sctp_transport *transport)
+{
+	if (!mod_timer(&transport->probe_timer,
+		       jiffies + transport->probe_interval))
+		sctp_transport_hold(transport);
+}
+
+void sctp_transport_reset_raise_timer(struct sctp_transport *transport)
+{
+	if (!mod_timer(&transport->probe_timer,
+		       jiffies + transport->probe_interval * 30))
+		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.
@@ -236,7 +231,7 @@ void sctp_transport_set_owner(struct sctp_transport *transport,
 void sctp_transport_pmtu(struct sctp_transport *transport, struct sock *sk)
 {
 	/* If we don't have a fresh route, look one up */
-	if (!transport->dst || transport->dst->obsolete) {
+	if (!transport->dst || READ_ONCE(transport->dst->obsolete)) {
 		sctp_transport_dst_release(transport);
 		transport->af_specific->get_dst(transport, &transport->saddr,
 						&transport->fl, sk);
@@ -255,12 +250,150 @@ void sctp_transport_pmtu(struct sctp_transport *transport, struct sock *sk)
 		transport->pathmtu = sctp_dst_mtu(transport->dst);
 	else
 		transport->pathmtu = SCTP_DEFAULT_MAXSEGMENT;
+
+	sctp_transport_pl_update(transport);
+}
+
+void sctp_transport_pl_send(struct sctp_transport *t)
+{
+	if (t->pl.probe_count < SCTP_MAX_PROBES)
+		goto out;
+
+	t->pl.probe_count = 0;
+	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_BASE_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);
+		}
+	}
+
+out:
+	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);
+	t->pl.probe_count++;
+}
+
+bool sctp_transport_pl_recv(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);
+
+	t->pl.pmtu = t->pl.probe_size;
+	t->pl.probe_count = 0;
+	if (t->pl.state == SCTP_PL_BASE) {
+		t->pl.state = SCTP_PL_SEARCH; /* Base -> Search */
+		t->pl.probe_size += SCTP_PL_BIG_STEP;
+	} else if (t->pl.state == SCTP_PL_ERROR) {
+		t->pl.state = SCTP_PL_SEARCH; /* Error -> Search */
+
+		t->pl.pmtu = t->pl.probe_size;
+		t->pathmtu = t->pl.pmtu + sctp_transport_pl_hlen(t);
+		sctp_assoc_sync_pmtu(t->asoc);
+		t->pl.probe_size += SCTP_PL_BIG_STEP;
+	} else if (t->pl.state == SCTP_PL_SEARCH) {
+		if (!t->pl.probe_high) {
+			if (t->pl.probe_size < SCTP_MAX_PLPMTU) {
+				t->pl.probe_size = min(t->pl.probe_size + SCTP_PL_BIG_STEP,
+						       SCTP_MAX_PLPMTU);
+				return false;
+			}
+			t->pl.probe_high = SCTP_MAX_PLPMTU;
+		}
+		t->pl.probe_size += SCTP_PL_MIN_STEP;
+		if (t->pl.probe_size >= t->pl.probe_high) {
+			t->pl.probe_high = 0;
+			t->pl.state = SCTP_PL_COMPLETE; /* Search -> Search Complete */
+
+			t->pl.probe_size = t->pl.pmtu;
+			t->pathmtu = t->pl.pmtu + sctp_transport_pl_hlen(t);
+			sctp_assoc_sync_pmtu(t->asoc);
+			sctp_transport_reset_raise_timer(t);
+		}
+	} else if (t->pl.state == SCTP_PL_COMPLETE) {
+		/* Raise probe_size again after 30 * interval in Search Complete */
+		t->pl.state = SCTP_PL_SEARCH; /* Search Complete -> Search */
+		t->pl.probe_size = min(t->pl.probe_size + SCTP_PL_MIN_STEP, SCTP_MAX_PLPMTU);
+	}
+
+	return t->pl.state == SCTP_PL_COMPLETE;
+}
+
+static bool sctp_transport_pl_toobig(struct sctp_transport *t, u32 pmtu)
+{
+	pr_debug("%s: PLPMTUD: transport: %p, state: %d, pmtu: %d, size: %d, ptb: %d\n",
+		 __func__, t, t->pl.state, t->pl.pmtu, t->pl.probe_size, pmtu);
+
+	if (pmtu < SCTP_MIN_PLPMTU || pmtu >= t->pl.probe_size)
+		return false;
+
+	if (t->pl.state == SCTP_PL_BASE) {
+		if (pmtu >= SCTP_MIN_PLPMTU && pmtu < SCTP_BASE_PLPMTU) {
+			t->pl.state = SCTP_PL_ERROR; /* Base -> Error */
+
+			t->pl.pmtu = SCTP_BASE_PLPMTU;
+			t->pathmtu = t->pl.pmtu + sctp_transport_pl_hlen(t);
+			return true;
+		}
+	} else if (t->pl.state == SCTP_PL_SEARCH) {
+		if (pmtu >= SCTP_BASE_PLPMTU && pmtu < t->pl.pmtu) {
+			t->pl.state = SCTP_PL_BASE;  /* Search -> Base */
+			t->pl.probe_size = SCTP_BASE_PLPMTU;
+			t->pl.probe_count = 0;
+
+			t->pl.probe_high = 0;
+			t->pl.pmtu = SCTP_BASE_PLPMTU;
+			t->pathmtu = t->pl.pmtu + sctp_transport_pl_hlen(t);
+			return true;
+		} else if (pmtu > t->pl.pmtu && pmtu < t->pl.probe_size) {
+			t->pl.probe_size = pmtu;
+			t->pl.probe_count = 0;
+		}
+	} else if (t->pl.state == SCTP_PL_COMPLETE) {
+		if (pmtu >= SCTP_BASE_PLPMTU && pmtu < t->pl.pmtu) {
+			t->pl.state = SCTP_PL_BASE;  /* Complete -> Base */
+			t->pl.probe_size = SCTP_BASE_PLPMTU;
+			t->pl.probe_count = 0;
+
+			t->pl.probe_high = 0;
+			t->pl.pmtu = SCTP_BASE_PLPMTU;
+			t->pathmtu = t->pl.pmtu + sctp_transport_pl_hlen(t);
+			sctp_transport_reset_probe_timer(t);
+			return true;
+		}
+	}
+
+	return false;
 }
 
 bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu)
 {
-	struct dst_entry *dst = sctp_transport_dst_check(t);
 	struct sock *sk = t->asoc->base.sk;
+	struct dst_entry *dst;
 	bool change = true;
 
 	if (unlikely(pmtu < SCTP_DEFAULT_MINSEGMENT)) {
@@ -271,13 +404,17 @@ bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu)
 	}
 	pmtu = SCTP_TRUNC4(pmtu);
 
+	if (sctp_transport_pl_enabled(t))
+		return sctp_transport_pl_toobig(t, pmtu - sctp_transport_pl_hlen(t));
+
+	dst = sctp_transport_dst_check(t);
 	if (dst) {
 		struct sctp_pf *pf = sctp_get_pf_specific(dst->ops->family);
 		union sctp_addr addr;
 
 		pf->af->from_sk(&addr, sk);
 		pf->to_sk_daddr(&t->ipaddr, sk);
-		dst->ops->update_pmtu(dst, sk, NULL, pmtu);
+		dst->ops->update_pmtu(dst, sk, NULL, pmtu, true);
 		pf->to_sk_daddr(&addr, sk);
 
 		dst = sctp_transport_dst_check(t);
@@ -348,7 +485,8 @@ void sctp_transport_update_rto(struct sctp_transport *tp, __u32 rtt)
 		pr_debug("%s: rto_pending not set on transport %p!\n", __func__, tp);
 
 	if (tp->rttvar || tp->srtt) {
-		struct net *net = sock_net(tp->asoc->base.sk);
+		struct net *net = tp->asoc->base.net;
+		unsigned int rto_beta, rto_alpha;
 		/* 6.3.1 C3) When a new RTT measurement R' is made, set
 		 * RTTVAR <- (1 - RTO.Beta) * RTTVAR + RTO.Beta * |SRTT - R'|
 		 * SRTT <- (1 - RTO.Alpha) * SRTT + RTO.Alpha * R'
@@ -360,10 +498,14 @@ void sctp_transport_update_rto(struct sctp_transport *tp, __u32 rtt)
 		 * For example, assuming the default value of RTO.Alpha of
 		 * 1/8, rto_alpha would be expressed as 3.
 		 */
-		tp->rttvar = tp->rttvar - (tp->rttvar >> net->sctp.rto_beta)
-			+ (((__u32)abs((__s64)tp->srtt - (__s64)rtt)) >> net->sctp.rto_beta);
-		tp->srtt = tp->srtt - (tp->srtt >> net->sctp.rto_alpha)
-			+ (rtt >> net->sctp.rto_alpha);
+		rto_beta = READ_ONCE(net->sctp.rto_beta);
+		if (rto_beta < 32)
+			tp->rttvar = tp->rttvar - (tp->rttvar >> rto_beta)
+				+ (((__u32)abs((__s64)tp->srtt - (__s64)rtt)) >> rto_beta);
+		rto_alpha = READ_ONCE(net->sctp.rto_alpha);
+		if (rto_alpha < 32)
+			tp->srtt = tp->srtt - (tp->srtt >> rto_alpha)
+				+ (rtt >> rto_alpha);
 	} else {
 		/* 6.3.1 C2) When the first RTT measurement R is made, set
 		 * SRTT <- R, RTTVAR <- R/2.
@@ -685,7 +827,7 @@ void sctp_transport_reset(struct sctp_transport *t)
 void sctp_transport_immediate_rtx(struct sctp_transport *t)
 {
 	/* Stop pending T3_rtx_timer */
-	if (del_timer(&t->T3_rtx_timer))
+	if (timer_delete(&t->T3_rtx_timer))
 		sctp_transport_put(t);
 
 	sctp_retransmit(&t->asoc->outqueue, t, SCTP_RTXR_T3_RTX);